Operative Techniques in Orthopaedic Surgical Oncology [2 ed.] 9781451193275, 1451193270, 9781496344793, 1496344790

Table of contents :
Cover
Editors
Dedication
Foreword to the First Edition
Preface
Preface to the First Edition
Preface to Original Text
Acknowledgments
Chapter 1
Chapter 2
Chapter 3
Chapter 4
Chapter 5
Chapter 6
Chapter 7
Chapter 8
Chapter 9
Chapter 10
Chapter 11
Chapter 12
Chapter 13
Chapter 14
Chapter 15
Chapter 16
Chapter 17
Chapter 18
Chapter 19
Chapter 20
Chapter 21
Chapter 22
Chapter 23
Chapter 24
Chapter 25
Chapter 26
Chapter 27
Chapter 28
Chapter 29
Chapter 30
Chapter 31
Chapter 32
Chapter 33
Chapter 34
Chapter 35
Chapter 36
Chapter 37
Chapter 38

Citation preview

Editors Martin M. Malawer MD, FACS Director of Orthopedic Oncology Professor, Orthopedic Surgery George Washington University School of Medicine Professor (Clinical Scholar) of Orthopedics and Professor of Pediatrics (Hematology and Oncology) Georgetown University School of Medicine Washington, District of Columbia Consultant, Pediatric and Surgery Branch National Cancer Institute National Institutes of Health Bethesda, Maryland James C. Wittig MD Vice Chairman Chief, Orthopedic Oncology Department of Orthopedic Surgery Director, Sarcoma Division John Theurer Cancer Center Hackensack University Medical Center Hackensack, New Jersey Professor of Orthopedic Surgery Director of Orthopedic Oncology Department of Orthopedic Surgery Seton Hall University School of Health and Medical Sciences South Orange, New Jersey Jacob Bickels MD The National Unit of Orthopedic Oncology Tel-Aviv Sourasky Medical Center Professor of Orthopedic Surgery Sackler Faculty of Medicine Tel-Aviv University Tel-Aviv, Israel Sam W. Wiesel MD EDITOR-IN-CHIEF Chairman and Professor Department of Orthopaedic Surgery Georgetown University Medical School Washington, DC

Contributors

Adesegun Abudu, FRCS Orthopaedic Surgeon Oncology Service—Oncology Unit Royal Orthopaedic Hospital Birmingham, United Kingdom Jacob Bickels, MD The National Unit of Orthopedic Oncology Tel-Aviv Sourasky Medical Center Professor of Orthopedic Surgery Sackler Faculty of Medicine Tel-Aviv University Tel-Aviv, Israel Loretta B. Chou, MD Professor and Chief of Foot and Ankle Surgery Department of Orthopaedic Surgery Stanford University Stanford, California Ernest U. Conrad III, MD Professor, Director of Sarcoma Service Department of Orthopaedics and Sports Medicine University of Washington School of Medicine Director Department of Orthopaedics and Sports Medicine Seattle Children's Hospital Seattle, Washington Braden J. Criswell, MD Palo Alto Medical Foundation Research Institute Palo Alto, California Jeffrey J. Eckardt, MD Professor and Chair Department of Orthopaedic Surgery University of California, Los Angeles Attending Surgeon Department of Orthopaedic Surgery UCLA Medical Center Santa Monica & Ronald Reagan UCLA Medical Center

Los Angeles, California Yair Gortzak, MD Head of the Orthopedic Oncology Clinic Tel Aviv Sourasky Medical Center Tel Aviv, Israel Robert Grimer, MD Professor, Orthopedic Oncology Consultant Orthopaedic Surgeon The Oncology Unit Royal Orthopaedic Hospital Birmingham, United Kingdom Eyal Gur, MD Director, Unit of Microsurgery Head, Department of Reconstructive and Aesthetic Surgery Department of Plastic Surgery Tel Aviv Sourasky Medical Center Senior Lecturer Sackler School of Medicine, Tel Aviv University Tel Aviv, Israel Yvette Ho, MD Resident Physician Department of Orthopedic Surgery Maimonides Medical Center Brooklyn, New York Lee Jeys, MD Consultant Surgeon Department of Oncology Royal Orthopaedic Hospital Birmingham, United Kingdom Norio Kawahara, MD, PhD Clinical Professor Department of Orthopaedic Surgery Kanazawa University School of Medicine Ishikawa, Japan Kristen Kellar-Graney, MS Tumor Biologist and Clinical Researcher Washington Musculoskeletal Tumor Center Bethesda, Maryland

Piya Kiatisevi, MD Orthopaedic Oncology Unit Institute of Orthopaedics Lerdsin Hospital Bangkok, Thailand Yehuda Kollender, MD Department Director Attending Surgeon, National Unit of Orthopedic Oncology Tel Aviv Sourasky Medical Center Senior Lecturer Sackler School of Medicine, Tel Aviv University Tel Aviv, Israel Jennifer Lisle, MD Assistant Professor of Orthopedics and Rehabilitation Assistant Professor of Pediatrics University of Vermont College of Medicine The University of Vermont Children's Hospital Burlington, Vermont Martin M. Malawer, MD, FACS Director of Orthopedic Oncology Professor, Orthopedic Surgery George Washington University School of Medicine Professor (Clinical Scholar) of Orthopedics and Professor of Pediatrics (Hematology and Oncology) Georgetown University School of Medicine Washington, District of Columbia Consultant, Pediatric and Surgery Branch National Cancer Institute National Institutes of Health Bethesda, Maryland Hideki Murakami, MD Lecturer of Orthopaedic Surgery Department of Orthopaedic Surgery Kanazawa University School of Medicine Ishikawa, Japan Vincent Ng, MD

Senior Fellow Attending Department of Orthopaedics and Sports Medicine University of Washington School of Medicine University of Washington Medical Center Seattle, Washington Xiaohui Niu, MD Professor Department of Orthopedic Oncology Peking University Chief Department of Orthopedic Oncology Beijing Ji Shui Tan Hospital Beijing, China Tamir Pritsch, MD Department of Orthopaedic Surgery Tel Aviv Sourasky Medical Center Tel Aviv, Israel Amir Sternheim, MD Attending Orthopaedic Surgeon Specialist in Oncology, Hip and Knee Surgery National Unit of Orthopaedic Oncology Tel Aviv Sourasky Medical Center Tel Aviv, Israel Daria Brooks Terrell, MD Department of Orthopedic Surgery Vice Chairman of the Department of Surgery St. Bernard Hospital Chicago, Illinois Katsuro Tomita, MD, PhD Professor Emeritus Department of Orthopaedic Surgery Kanazawa University President Kanazawa University Hospital Ishikawa, Japan Jason Weisstein, MD, MPH, FACS Director of Total Joint Replacement Surgery and Musculoskeletal Oncology

Desert Orthopedic Center Rancho Mirage, California James C. Wittig, MD Vice Chairman Chief, Orthopedic Oncology Department of Orthopedic Surgery Director, Sarcoma Division John Theurer Cancer Center Hackensack University Medical Center Hackensack, New Jersey Professor of Orthopedic Surgery Director of Orthopedic Oncology Department of Orthopedic Surgery Seton Hall University School of Health and Medical Sciences South Orange, New Jersey Yehuda Wolf, MD Clinical Associate Professor Department of Surgery Tel Aviv University Department Head Department of Vascular Surgery Tel Aviv Sourasky Medical Center Tel Aviv, Israel Hairong Xu, MD Professor Department of Orthopedic Oncology Peking University Chief Department of Orthopedic Oncology Beijing Ji Shui Tan Hospital Beijing, China Ravit Yanko-Arzi, MD Attending Surgeon Department of Plastic Surgery Tel Aviv Sourasky Medical Center Tel Aviv, Israel Arik Zaretski, MD Head of the Micro-Surgery Division of the Plastic Surgery Department Tel Aviv Ichilov Hospital

Tel Aviv Sourasky Medical Center Tel Aviv, Israel

Dedication To three great innovators, pioneers, developers, and critical thinkers in the field of orthopedic oncology; All of whom I have had the distinct pleasure of working with. Although no longer with us, the legacy of these men remains steadfast. Dr. Kenneth C. Francis, Professor of Orthopedic Surgery at the New York University School of Medicine and the first orthopedic surgeon to be named as the Chief of the Bone Tumor Service (presently Orthopedic Oncology) at the Memorial Sloan Kettering Cancer Center. Dr. Ralph Marcove—the first and only fellow of Dr. Kenneth Francis, who became Chief of the Bone Tumor Service at Memorial Sloan Kettering Cancer Center. Both Dr. Francis and Dr. Marcove independently developed the original techniques for orthopedic oncology surgery and limb sparing surgery with prosthetic replacements—during the 1970s—which they helped to design. Both surgeons were forward thinkers and had exceptional surgical skills. They changed the ‘accepted’ treatment paradigm from amputation to limbsparing surgery for most patients with bone and soft tissue sarcomas.

They both—independently—developed prosthetic replacements for the shoulder, scapula, partial and total femur, as well as the proximal tibia; and each described and published their respective surgical techniques. And finally, to Dr. William F. Enneking, Professor and Chairman of Orthopedic Surgery at the University of Florida under whom I completed my fellowship education. He was an outstanding teacher and a leading thinker in the development and classification of the natural biology and growth of bone and soft tissue sarcomas. His description of the significance of the anatomic site and concept of tumor compartment and fascial borders gave a sound biological basis for limb-sparing surgery. Dr. Enneking spent the majority of his career in Gainesville. He developed the initial Musculoskeletal Tumor Staging System which is still in use today. He educated generations of orthopedic surgeons and specifically many fine orthopedic oncologists in practice today. MM I would like to dedicate this book to my loving parents, brother, sister, and nieces who have always provided me with the support I needed to succeed in medical school, residency, and my career as an orthopedic oncologist. I would also like to acknowledge my mentor and friend Dr. Martin Malawer who provided me with the strongest possible foundation in orthopedic oncology during my fellowship and who has always been a constant source of encouragement throughout the years! JW This book is dedicated with enormous love to my extraordinary wife Shelly, who supported me and raised our four darling children while I did what I did. My heartfelt wish is that these pages will help to bring at least a small ray of clarity and hope to the reader. JB

Foreword to the First Edition In the past two decades significant progress has occurred, in the management of patients with musculoskeletal cancers, that has improved both the survival and the quality of life of afflicted patients. Changes in the management of these patients have mirrored trends in the entire field of oncology. The most significant change has been improvement in the surgical techniques for the resection of musculoskeletal cancers based on a detailed understanding of the anatomic features of each particular tumor site, as well as an appreciation of the natural biology that affects the local spread of these tumors. Operative Techniques in Orthopaedic Surgical Oncology provides a detailed description of important changes in the surgical approach to these patients. Amputation, once the mainstay of treatment for patients with bony and soft-tissue extremity sarcomas, has now largely been replaced by limb-sparing surgery using innovative approaches to cancer resection and the advent of new reconstruction techniques that can restore function in ways not possible even a decade ago. Although debilitating amputations are still required for some patients with locally extensive cancers, most patients with these tumors can look forward to surgical procedures that will maximize their functional outcome. The sophistication of many of these limb-sparing surgical approaches has resulted in a shift in the expertise required to perform these procedures and, increasingly, specialists in the management of musculoskeletal tumors have arisen to provide these patients with the benefits of these advances. A second change in the management of these patients has been the introduction of combined modality treatment utilizing the concerted application of surgery, radiation therapy and chemotherapy in a carefully integrated fashion to maximize survival and quality of life. The use of local radiation therapy has had a profound impact on the ability to achieve local control. Cooperation between surgeons and radiation therapists often results in the tailoring of surgical procedures to maximize the combined application of these two effective treatment modalities. Although impact on overall survival has not been demonstrated due to the addition of radiation therapy, important advances in improving the quality of life of patients receiving this combined-modality treatment have been evident. A third change impacting on the survival of patients with musculoskeletal cancers has been the aggressive resection of metastatic deposits. Surgery remains the most effective treatment for adult patients with limited metastatic cancer, and durable disease-free and overall survival can be achieved by the vigorous resection of metastases arising from these cancers. Although the use of adjuvant chemotherapy has had dramatic impact on the treatment of many musculoskeletal cancers in children, the impact of chemotherapy on adults remains a controversial issue. Although transient responses can be seen in adults with many types of soft-tissue sarcomas, they are very rarely curative and the development of more effective systemic treatments for patients with softtissue sarcomas remains a major challenge in the future treatment of patients with this disease. The state-of-the-art surgical techniques described in this text, applied in the context of integrated cancer therapy, can provide great benefit to patients with musculoskeletal cancers. Steven A. Rosenberg, MD, PhD Chief, Surgery Branch National Cancer Institute National Institutes of Health Bethesda, Maryland

Foreword was originally published for Malawer M, Sugarbaker P. Musculoskeletal Cancer Surgery: Treatment of Sarcomas and Allied Diseases. Norwell, MA: Kluwer Academic Press; 2001.

Preface The purpose of the second edition of Operative Techniques in Orthopaedic Surgery remains the same as the first: to describe in a detailed, step-by-step manner the technical parts of “how to do” the majority of orthopaedic procedures. It is assumed that the surgeon understands the “why” and the “when,” although this information is covered in outline form at the beginning of each procedure. Each of the nine major sections has been carefully reviewed and updated in both its content and artwork. The second edition has given each section editor the ability to include additional procedures and has also placed more emphasis in creating online content which is easily accessible and fully searchable. The section editors and chapter authors have done an excellent job. Each has specific expertise and experience in their area and has given their time and effort most generously. It has again been stimulating to interact with these wonderful and talented people, and I am honored to have been able to play a part in this rewarding experience. I also would like to thank all of the people at Wolters Kluwer. Dave Murphy has been especially helpful and had a great deal of input into this edition, as with the first edition. I would like, as well, to acknowledge Bob Hurley, who was a driving force for the first edition and has been a great resource for this second one as well. Finally, special thanks goes to Brian Brown, the new acquisitions editor. It has been a wonderful experience to work with Brian who has done an excellent job of bringing this text to completion. Sam W. Wiesel, MD Washington, DC January 2, 2015

Preface to the First Edition This is the third book in a series that documents and details the progress and innovations made in surgical techniques in the field of Orthopaedic Oncology. In 1992, Drs. Sugarbaker and Malawer published Musculoskeletal Surgery for Cancer: Principles and Techniques. This book was comprised of 30 chapters in black and white, describing in detail the new procedures in Orthopaedic Oncology. This text was and is used internationally as a standard text in the field of Orthopaedic Oncology; it was translated into Chinese, Spanish, Russian, and Portuguese. In 2001, Malawer and Sugarbaker published a completely revised and updated textbook, Musculoskeletal Cancer Surgery: Treatment of Sarcomas and Allied Diseases. One of the first surgical texts published in color, including full color illustrations and schematics. This book was based on over 50 years of combined surgical and oncological experience. The 2001 text has recently been translated into Chinese by one of the outstanding medical publishing houses in China, Shanghai Scientific and Technical Publishers, and is widely used by the many of new and developing orthopaedic oncologists at some of the leading universities and teaching hospitals. This book, Operative Techniques in Orthopaedic Surgical Oncology, is the natural progression as a representative text of the current state of Orthopaedic Oncology today. The coauthors of this text are Drs. James C. Wittig and Jacob Bickels. This text represents a movement in the field toward Orthopaedic Oncology standing on its own as a true subspecialty in the field of Orthopaedics. They and Dr. Malawer represent over 60 years of surgical experience dedicated to the treatment of bone and soft tissue sarcomas. This book is a reprint of Part 4, Oncology, of Operative Techniques in Orthopaedic Oncology, Volume 2, edited by Sam W. Wiesel. It consists of 4 sections, and 42 chapters in total: Section 1, Surgical Management; Section 2, Shoulder Girdle and Upper Extremities; Section 3, Spine and Pelvis; and Section 4, Lower Extremities. In addition, for the first time, there are 25 surgical videos, edited and correlated with most chapters. Many of these videos have been shown at various national and international meetings. Thus, taken together with the text, the surgeon is given the most complete visual as well as didactic information to date. The purpose of this text, as with the previous ones, is to illustrate and detail the surgical techniques, indications, and anatomy of each procedure. From the Preface of the previous edition, it was stated that “surgery is a visual field, and that the surgeon works in three dimensions.” That concept holds just as true today, and has only been enhanced by digital, three-dimensional, navigational, and other real-time imaging techniques. The prior Preface continues on to say:

Therefore the majority of contents of this book are accompanied by photographs and illustrations of the surgical procedure, as well as preoperative studies that the authors feel are uniquely important. The surgical descriptions, anatomic depictions, and the significance of each imaging study to each operative procedure are emphasized … It was the purpose of the authors to present [this] data in a simple visual format. The authors of the current text hope that this book is helpful to all surgeons undertaking the care of sarcoma patients. Additionally, that this text both reinforces and builds upon the previous foundation of techniques in the field of Orthopaedic Oncology. Martin M. Malawer, MD

Preface to Original Text Preface to original textbook Malawer M. and Sugarbaker P. Musculoskeletal Cancer Surgery: Treatment of Sarcomas and Allied Diseases. Kluwer Academic Press; 2001. Musculoskeletal cancer surgery has undergone dramatic changes within the past two decades. Limb-sparing surgery is the hallmark of the surgical advances developed by this specialty. The role of the orthopaedic oncology surgeon in the 1970s was to perform high-level amputations. This is what distinguished the orthopaedic cancer surgeon from the general orthopaedic surgeon. The development of limb-sparing surgery, in conjunction with the dynamic advances in imaging and chemotherapy, created the specialty of musculoskeletal (orthopaedic) oncology. The operative procedures performed today barely existed two decades ago. Today, approximately 90-95% of all bone and soft-tissue sarcomas can be treated by limb-sparing surgery. The aim of this book is to present in a concise, organized and well-illustrated format, the surgical techniques involved with limb-sparing procedures of the entire musculoskeletal system, including the upper and lower extremities as well as the pelvic and shoulder girdle. These techniques are a combination of surgical procedures that used to be considered of interest only to the general surgeon, vascular surgeon, plastic surgeon and orthopaedic surgeon. The development of these multiple-treatment strategies and techniques has created the field of musculoskeletal cancer surgery as we know it today. The surgical experience of the two authors, Martin M. Malawer, MD, and Paul H. Sugarbaker, MD, spans more than two decades each. The combined experience of Dr. Malawer, Professor of Orthopaedic Surgery at George Washington University, Children's Hospital National Medical Center, and the Washington Cancer Institute Department of Orthopaedic Oncology, and Dr. Sugarbaker, who developed several of the techniques described in this book while at the National Cancer Institute, Bethesda, Maryland, forms the foundation for this book. The techniques described in these pages have been developed by both authors over the past two decades. The aim of this textbook is to illustrate well a step-by-step approach to limb-sparing procedures of the musculoskeletal system. These techniques, although not unique, are described specifically from the authors' experience, which began in the early 1970s and continues today. Dr. Malawer has extensively reported different techniques for limb-sparing resections and endoprosthetic reconstructions. The technique of allograft replacement was developed in the early 1970s and utilized widely until the 1980s. Such techniques are not utilized by the authors but are well described elsewhere. Surgery is a visual field, and the surgeon works in three dimensions. Therefore, the majority of the contents of this book are accompanied by photographs and illustrations of the surgical procedure as well as preoperative studies that the authors feel are uniquely important. The surgical descriptions, anatomic depictions, and the significance of each imaging study to each operative procedure are emphasized. Since the mid-1970s the two authors have provided surgical care for approximately 4000 patients with benign, malignant and metastatic lesions, in children and adults. Detailed files, including operative photographs, pathology slides, Kodachrome slides and slides of the significant imaging studies for all of the major cases have been kept on each operative procedure. This collection is housed at the Center for Orthopaedic Oncology and Musculoskeletal Research at the Washington Cancer Institute and is available to American and international surgeons and oncologists for study and research purposes. Despite the complexity of limb-sparing surgical procedures and the multiple imaging studies, it was the purpose of the authors to present these data in a simple visual format. The bibliography is limited in most chapters, because the techniques described were developed by the authors themselves. The general chapters are wellreferenced with the most up-to-date citations. This book contains 36 chapters, divided into four sections. It addresses the basic pathology, surgical technique

and management of all extremity and pelvic and shoulder girdle tumors as well as abdominal and truncal sarcoma surgery. P.xv Chapter 1 includes a discussion of bone and soft-tissue sarcomas, including their epidemiology, radiographic characteristics and pathology. Biopsy techniques are discussed in Chapter 2. In Chapter 3, chemotherapy is discussed, outlining the chemotherapeutic agents that are effective in the treatment of bone and soft-tissue sarcomas. Dr. Dennis Priebat details the chemotherapy strategy that has evolved over the past 20 years. The experience of isolated-limb perfusion, a new technique used to treat sarcomas, is described in Chapter 4. Dr. Brian Fuller chief of the Radiation Oncology Branch at the National Cancer Institute, in Chapter 5, describes the most current and comprehensive strategy for radiation therapy for extremity sarcomas. Chapter 6 discusses the use of cryosurgery in the treatment of certain bone tumors. This technique was developed by Dr. Ralph Marcove at Memorial Sloan Kettering Cancer Center and has been continued by the authors. Chapters 7 and 8 summarize the management of abdominal and pelvic sarcomas. The author, Dr. Paul Sugarbaker, has uniquely developed many techniques over the past 25 years. Chapters 9, 10 and 11 provide overviews of the treatment of tumors of the shoulder girdle, pelvic girdle and metastatic bone tumors, respectively. These chapters lay the foundation for the specific limb-sparing procedures in the remaining portion of the textbook. Section Two describes in detail the techniques for muscle group resections of the lower extremity including gluteus maximus, adductor muscle group, quadriceps muscle group, posterior thigh and popliteal space. Section Three discusses the surgical amputations utilized in orthopaedic oncology surgery. These tend to be high-level amputations with which orthopaedic and general surgeons tend not to be familiar. Forequarter amputation and the various types of hemipelvectomy are described. Dr. Sugarbaker developed the technique of an anterior myocutaneous flap for patients with massively contaminated pelvic and buttock structures that cannot be resected by the standard posterior flap hemipelvectomy. These operative procedures were often deemed difficult and radical, but are still used today to cure certain patients who cannot be treated by limb-sparing surgeries. Phantom pain, a complication following an amputation for cancer patients, is discussed in Chapter 24. Due to the neuropathic effects of the chemotherapeutic agents, as well as the young age of these patients, this problem occurs frequently. Dr. Lee Ann Rhodes described treatment considerations for phantom limb pain. Section Four describes in detail the limb-sparing procedures around the pelvis, proximal and distal femur, proximal tibia, fibula, proximal humerus and scapula. Although these procedures are performed at many centers throughout the world today, the techniques, morbidity and complications vary tremendously. The techniques as described by Dr. Malawer, which he has perfected over the past 20 years, are presented in detail. The required staging studies and unique anatomic considerations, from a surgeon's viewpoint, are outlined for each anatomic site, with special considerations for the evaluation of the imaging studies. The Appendix includes two chapters of interest to the musculoskeletal surgeon. Appendix A is a description of an abdominoinguinal incision developed by Dr. Constantine Karakousis for resection of pelvic tumors. This is a combined intra- and extraperitoneal approach. Canine osteosarcomas are discussed by Dr. Charles Kuntz. Osteosarcomas in dogs are extremely common, and the techniques and basis of limb-sparing surgical techniques in dogs offer an excellent orthopaedic animal model and are of interest to musculoskeletal cancer surgeons. Martin M. Malawer, MD

Acknowledgments Halstead once stated that “the operating room was the Laboratory for the surgeon.” This is as true today as it was a century ago. The surgical techniques described in this textbook were developed over a course of now 30 years in the treatment of over 6,000 patients. We would like to acknowledge our patients for their belief in us as surgeons and in our ability to restore the function to their extremities in lieu of an amputation. For those patients who did require an amputation, we acknowledge the tremendous will that they have had. Surgery and surgical training is a three-way communication between patients, fellows, and senior surgeons. This spoken and unspoken dialogue has been the foundation of many of these concepts, ideas, and motivations presented in this textbook. We would like to acknowledge all of the residents and fellows that we have trained. This textbook would not exist without the outstanding artistic skills of Joyce Hurwitz. Mrs. Hurwitz has spent 30 years in close cooperation with the senior authors, illustrating multiple publications, presentations, posters, and textbooks. Her utmost knowledge of surgical anatomy, combined with her interest and motivation in participating within the scientific community, sets her apart as a truly gifted individual. Finally, the authors would like to acknowledge the hard work and dedication of all of the contributors. We are especially appreciative of the long hours and days that our Senior Research Assistant, Kristen Kellar-Graney, has spent, without which this book never would have been completed. It goes without saying that a text of this magnitude took many long and hard hours of work by the authors but, more important, time away from our wives and families, whom we greatly appreciate and acknowledge. Martin M. Malawer, MD, FACS 2011

Chapter 1 Overview of Musculoskeletal Tumors and Preoperative Evaluation Martin M. Malawer Amir Sternheim

BACKGROUND An understanding of the basic biology and pathology of bone and soft tissue tumors is essential for appropriate planning of their treatment. This chapter reviews the unique biologic behavior of soft tissue and bone sarcomas, which provides the basis for their staging and resection and the use of appropriate adjuvant treatment modalities. A detailed description of the clinical, radiographic, and pathologic characteristics for the most common sarcomas is presented.

EPIDEMIOLOGY Soft tissue and bone sarcomas are a rare and heterogeneous group of tumors. These neoplasms represent less than 0.2% of all adult and 15% of pediatric malignancies. As of 2013, the annual incidence in the United States, which remains relatively constant, is approximately 11,400 soft tissue sarcomas (STS) and 3010 new bone sarcomas.1 About 4390 deaths from STS and 1440 deaths from bone cancers are expected in 2013. In adults, over 40% of primary bone cancers are chondrosarcomas. This is followed by osteosarcomas (OSs) (28%), chordomas (10%), Ewing tumors (8%), and malignant fibrous histiocytoma (MFH)/fibrosarcomas (4%). The remainder of cases are several rare types of bone cancers. In children and teenagers (those younger than 20 years), OS (56%) and Ewing tumors (34%) are much more common than chondrosarcoma (6%). In the United States, the 5-year survival rates for all bone sarcomas is about 70%. OS and Ewing sarcoma were comparable among 15 to 29 years old, about 60% for the most recent era. The U.S. bone cancer mortality was highest for males and females 15 to 19 years of age. The 5-year survival rates for localized STS is 83% in 2013. This drops to 16% for systemic disease.2

RISK FACTORS Risk factors for soft tissue and bone sarcomas include previous radiation therapy, exposure to chemicals (eg, vinyl chloride, arsenic); immunodeficiency; prior injury (scars, burns); chronic tissue irritation (foreign body implants, lymphedema, chronic infection); neurofibromatosis; Paget disease; bone infarcts; and genetic cancer syndromes (eg, hereditary retinoblastoma, Li-Fraumeni syndrome, Gardner syndrome, Rothmund-Thomson syndrome, Werner syndrome, Bloom syndrome), Maffucci syndrome, Ollier disease, multiple osteochondromatosis, and hereditary multiple exostoses. In most patients, however, no specific etiology can be identified.

PATHOPHYSIOLOGY AND BIOLOGIC BEHAVIOR Sarcomas originate primarily from elements of the mesodermal embryonic layer.

STS are classified according to the adult tissue that they resemble. Bone sarcomas usually are classified according to the type of matrix production: Osteoid-producing sarcomas are classified as OSs, and chondroid-producing sarcomas are classified as chondrosarcomas. Tumors arising in bone and soft tissues have characteristic patterns of biologic behavior because of their common mesenchymal origin and anatomic environment. Those unique patterns form the basis of the staging system and current treatment strategies. Histologically, sarcomas are graded as low, intermediate, or high grade. The grade is based on tumor morphology, extent of pleomorphism, atypia, mitosis, matrix production, and necrosis, with the two main factors being mitotic count and spontaneous tumor necrosis. Tumor grade represents the tumor's biologic aggressiveness and correlates with the likelihood of metastases. Low-grade lesions rarely metastasize. High-grade lesions metastasize in over 20% of patients. Sarcomas form a solid mass that grows centrifugally, with the periphery of the lesion being the least mature. In contradistinction to the true capsule that surrounds benign lesions, which is composed of compressed normal cells, sarcomas usually are enclosed by a reactive zone or pseudocapsule. This pseudocapsule consists of compressed tumor cells and a fibrovascular zone of reactive tissue with a variable inflammatory component that interacts with the surrounding normal tissues. The thickness of the reactive zone varies according to the histogenic type and grade of malignancy. Highgrade sarcomas have a poorly defined reactive zone that may be locally invaded by the tumor (FIG 1A). Tumor foci within the reactive zone are called satellite lesions. High grade, and occasionally low grade, may break through the pseudocapsule to form metastases, termed skip metastases, within the same anatomic compartment in which the lesion is located. By definition, these are locoregional micrometastases that have not passed through the circulation (FIG 1B). This phenomenon may be responsible for local recurrences that develop in spite of apparently negative margins after a resection. Although low-grade sarcomas regularly interdigitate into the reactive zone, they rarely form tumor skip nodules beyond that area (FIG 1C,D). P.2

FIG 1 • A. Gross specimen. A pseudocapsule of a high-grade STS (arrowheads) composed of compressed tumor cells and a fibrovascular zone of reactive inflammatory response. B. Pathology specimen. Multiple satellite nodules (arrows) associated with a high-grade MFH. Note the normal intervening tissue. C. Biologic behavior of bone and STS. Unique features are formation of reactive zone, intracompartmental growth, and, rarely, the presence of skip metastases. Skip nodules are tumor foci not in continuity with the main tumor mass that form outside the pseudocapsule. “Satellite” nodules, by contrast, form within the pseudocapsule. D. Gross specimen. Skip metastases (arrows) from an OS of the distal femur. This finding is documented preoperatively in less than 5% of patients. E. Sagittal section of a high-grade OS of the distal femur. The growth plate, although not invaded by the tumor in this case, is not considered an anatomic barrier to tumor extension, probably because of the numerous vascular channels that pass through the growth plate to the epiphysis. However, the articular cartilage is an anatomic barrier to tumor extension and very rarely is directly violated by a tumor. F. Coronal section of a high-grade OS of the distal femur. Although gross involvement of the epiphysis and medial cortical breakthrough and soft tissue extension are evident, the articular cartilage is intact. This phenomenon allows intra-articular resection of high-grade sarcomas of the distal femur in most cases. Thick fascial planes are barriers to tumor extension. G. Axial MRI, showing a high-grade

leiomyosarcoma of the vastus lateralis and vastus intermedius muscles. The tumor does not penetrate, looking in a clockwise direction, the lateral intermuscular septum, the adductor compartment, and the aponeuroses of the sartorius and rectus femoris muscles. (Courtesy of Martin M. Malawer.) P.3 Sarcomas respect anatomic borders. Local anatomy influences tumor growth by setting natural barriers to extension. In general, sarcomas take the path of least resistance and initially grow within the anatomic compartment in which they arose. It is only at a later stage that the walls of the compartment are violated (either the cortex of a bone or aponeurosis of a muscle), at which time, the tumor breaks into a surrounding compartment. Typical anatomic barriers are articular cartilage, cortical bone, and fascial borders. The growth plate is not considered an anatomic barrier because it has numerous vascular channels that run through it to the epiphysis (FIG 1E-G). Sarcomas are defined as intracompartmental if they are encased within an anatomic compartment. Extracompartmental tumors are those that grow out through the compartment barrier or tumors that have arisen in extracompartmental spaces (space tumors), that is, popliteal fossa, groin, sartorial canal, axilla, and antecubital fossa (FIG 2A,B). Most bone sarcomas are bicompartmental at the time of presentation; they destroy the overlying cortex and extend directly into the adjacent soft tissues through the Haversian system and Volkmann canals of the cortical bone.

FIG 2 • Extracompartmental extension. Ewing sarcoma of the distal two-thirds of the femur (A) and OS of the proximal tibia (B). Note the extraosseous component of the tumor. Most high-grade bone sarcomas are

bicompartmental at the time of presentation (ie, they involve the bone of origin as well as the adjacent soft tissues). Tumors at that extent are staged as IIB. C. Plain radiograph of the proximal femur revealed direct invasion through the cortical bone with a pathologic fracture of the lesser trochanter (arrowheads). D. Axial MRI, showing metastatic bladder carcinoma to the posterior thigh. E. In surgery, exploration of the sciatic nerve revealed direct tumor involvement with extension under the epineural sheath. (Courtesy of Martin M. Malawer.) Carcinomas, which typically present in the extremities as metastatic disease, directly invade the surrounding tissues, irrespective of compartmental borders (FIG 2C-E). Joint involvement in sarcoma is uncommon because direct tumor extension through the articular cartilage is rare. Mechanisms of joint involvement in sarcoma are as follows: Pathologic fracture with seeding of the joint cavity Pericapsular extension Structures that pass through the joint (eg, the cruciate ligaments) may act as a conduit for tumor growth (FIG 3). Transcapsular skip nodules: demonstrated in 1% of all OSs Direct articular extension

Metastatic Bone and Soft Tissue Sarcoma Unlike carcinomas, bone and STS disseminate almost exclusively through the blood. Hematogenous spread of extremity sarcomas is commonly manifested by pulmonary involvement and less commonly by bony involvement. Abdominal and pelvic STS, on the other hand, typically metastasize to the liver and lungs. Low-grade STS have a low (under 15%) rate of subsequent metastasis, whereas high-grade lesions have a significantly higher (over 20%) rate of metastasis. P.4

FIG 3 • A. The five major mechanisms of joint involvement by a bone sarcoma. The most common mechanisms are pathologic fracture and pericapsular extension. B. Pericapsular extension of an OS of the proximal humerus (arrowheads). C. Extension of an OS of the distal femur to the knee joint along the cruciate ligaments (arrow points to tumor); the articular cartilage is intact. Knee joint extension of a high-grade sarcoma of the distal femur is a rare event, necessitating extra-articular resection (ie, en bloc resection of the distal femur, knee joint, and a component of the proximal tibia). (Courtesy of Martin M. Malawer.)

Metastases from sarcomas to regional lymph nodes are uncommon; the condition is observed in only 13% of patients with STS and 7% of those with bone sarcomas at initial presentation. The prognosis is somewhat better than to that of distant metastasis (FIG 4). Most patients with high-grade primary bone sarcomas, unlike STS, have distant micrometastases at presentation; an estimated 80% of patients with OS have micrometastatic lung disease at the time of diagnosis. For this reason, in most cases, cure of a high-grade primary bone sarcoma can be achieved only with systemic chemotherapy and surgery.

FIG 4 • Metastatic sarcomas. Lateral plain radiograph of the lumbar spine, showing metastatic high-grade OS to the body of L3 vertebra (arrow). (Courtesy of Martin M. Malawer.) As mentioned, high-grade STS have a lower metastatic potential. Because of that difference in metastatic capability, the role of chemotherapy in the treatment of STS and its impact on survival are still matters of some controversy.

PROGNOSTIC FACTORS Prognostic factors for bone sarcomas include grade, size, extension of tumor beyond the bone cortex, regional and metastatic disease, and response of the tumor to chemotherapy (necrosis rate). Prognostic factors for STS include grade, tumor size, depth, age, margin status, location (proximal vs. distal), histologic subtypes, and metastatic disease.

Staging Staging is the process of classifying a tumor, especially a malignant tumor, with respect to its degree of differentiation, as well its local and distant extent, to plan the treatment and estimate the prognosis. Staging of a musculoskeletal tumor is based on the findings of the physical examination and the results of imaging studies. Biopsy and histopathologic evaluation are essential components of staging but should always be the final step. An important variable in any staging system for musculoskeletal tumors, unlike a staging system for carcinomas, is the grade of the tumor. The system most commonly used for the staging of STS is the one developed by the American Joint Committee on Cancer (Table 1).3 It is based primarily on the Memorial Sloan Kettering staging system and does not apply to rhabdomyosarcoma. Critics of this system point out that it is based largely on singleinstitution studies that were not subjected to multi-institutional tests of validity. The Musculoskeletal Tumor Society adopted staging systems that originally were described by Enneking et al4,5,6 for malignant soft tissue and bone tumors (Table 2), and the American Joint Committee P.5 P.6 on Cancer developed, with a few changes, a staging system for malignant bone tumors (Tables 3 and 4).

Table 1 System of the American Joint Committee on Cancer for the Staging of Soft Tissue Sarcomas Primary Tumor (T) TX

Primary tumor cannot be assessed

T0

No evidence of primary tumor

T1

Tumor ≤5 cm in greatest dimension (Size should be regarded as a continuous variable, and the measurement should be provided)

T1a

Superficial tumora

T1b

Deep tumora

T2

Tumor >5 cm in greatest dimensiona

T2a

T2b

Superficial tumora Deep tumor

Regional Lymph Nodes (N) NX

Regional lymph nodes cannot be assessed

N0

No regional lymph node metastasis

N1b

Regional lymph node metastasis

Distant Metastasis (M) M0

No distant metastasis

M1

Distant metastasis

Anatomic Stage/Prognostic Groups Stage IA

Stage IB

Stage IIA

Stage IIB

Stage III

Stage IV aSuperficial

T1a

N0

M0

G1, GX

T1b

N0

M0

G1, GX

T2a

N0

M0

G1, GX

T2b

N0

M0

G1, GX

T1a

N0

M0

G2, G3

T1b

N0

M0

G2, G3

T2a

N0

M0

G2

T2b

N0

M0

G2

T2a, T2b

N0

M0

G3

Any T

N1

M0

Any G

Any T

Any N

M1

Any G

tumor is located exclusively above the superficial fascia without invasion of the fascia; deep tumor is located either exclusively beneath the superficial fascia, superficial to the fascia with

invasion of or through the fascia, or both superficial yet beneath the fascia. bPresence of

positive nodes (N1) in M0 tumors is considered stage III.

Reprinted with permission from American Joint Committee on Cancer. Soft tissue sarcoma. In: Edge SB, Byrd DR, Compton CC, et al, eds. AJCC Cancer Staging Manual, ed 7. New York: Springer, 2010:291-298.

Table 2 System of Enneking et al for Staging of Bone Sarcomas Stage

Grade

Sitea

Metastasis

IA

Low grade

T1—intracompartmental

M0 (none)

IB

Low grade

T2—extracompartmental

M0 (none)

IIA

High grade

T1—intracompartmental

M0 (none)

IIB

High grade

T2—extracompartmental

M0 (none)

III

Metastatic

T1—intracompartmental

M1 (regional or distant)

III

Metastatic

T2—extracompartmental

M1 (regional or distant)

aIntracompartmental,

bone tumors are confined within the cortex of the bone; extracompartmental, bone tumors extend beyond the bone cortex. From Enneking WF. A system of staging musculoskeletal neoplasms. Clin Orthop Relat Res 1986; (204):9-24.

Table 3 System of the American Joint Committee on Cancer for the Staging of Bone Sarcomas Stage

Tumor Grade

Tumor Size

IA

Low

8 cm

IIA

High

8 cm

III

Any tumor grade, skip metastasesa

IV

Any tumor grade, any tumor size, distant metastases

aSkip metastases:

discontinuous tumors in the primary bone site.

Reprinted with permission from American Joint Committee on Cancer. Bone. In: Edge SB, Byrd DR, Compton CC, et al, eds. AJCC Cancer Staging Manual, ed 7. New York: Springer, 2010:281-290.

Enneking's classical staging system is based on three factors: histologic grade (G), site (T), and the presence or absence of metastases (M). The anatomic site (T) may be either intracompartmental (A) or extracompartmental (B). This information is obtained preoperatively on the basis of the data gained from the various imaging modalities. A tumor is classified as intracompartmental if it is bounded by natural barriers to extension, such as bone, fascia, synovial tissue, periosteum, or cartilage. An extracompartmental tumor may be either a tumor that has violated the borders of the compartment from which it originated, or a tumor that has originated and remained in the extracompartmental space. A tumor is assigned to stage III (M1) if a metastasis is present at a distant site or in a regional lymph node. Enneking's classification system is based on clinical data from an era in which chemotherapy was not given preoperatively and compartmental resections were much more common. Therefore, there was a clear correlation between the extent of the tumor at presentation, its relation to the boundaries of the compartment in which it is located, and the extent of surgery. A close correlation also was found between surgical stage of bone sarcoma and patient survival (FIG 5). Since that time, the use of neoadjuvant chemotherapy has been shown to decrease tumor size and facilitate limb-sparing surgery as well as reduce the local recurrence rate. As a result, compartmental resections have become rare. Nonetheless, Enneking's classification is based on the biologic behavior of soft tissue and bone sarcomas, and its underlying concept is as relevant today as it was in the early 1980s (see Tables 1,2,3 and 4).

Table 4 Enneking's System for the Staging of Benign Bone Tumors Typical Example Stage

Definition

Biologic Behavior

Soft Tissue Tumor

Bone Tumor

1

Latent

Remains static or heals spontaneously

Lipoma

Nonossifying fibroma

2

Active

Progressive growth, limited by natural barriers

Angiolipoma

Aneurysmal bone cyst

3

Aggressive

Progressive growth, invasive, not limited by natural barriers

Aggressive fibromatosis

Giant cell tumor

From Enneking WF, Spanier SS, Goodman MA. A system for the surgical staging of musculoskeletal sarcoma. Clin Orthop Relat Res 1980;153:106-120.

FIG 5 • Survival by Enneking's surgical stage of 219 patients with primary bone sarcoma. (Courtesy of Martin M. Malawer.) Approximate survival rates by stage for extremity STS are 90% for stage I, 70% for stage II, and 50% for stage III.

Staging Benign Bone Tumors Enneking also described a staging system for benign bone tumors, which remains the one that is most commonly used (see Table 4). That system is based on the biologic behavior of these tumors as suggested by their clinical manifestation and radiologic findings. Benign bone tumors grow in a centrifugal fashion, as do their malignant counterparts, and a rim of reactive bone typically is formed as a response of the host bone to the tumor. The extent of that reactive rim reflects the rate at which the tumor is growing: It usually is thick and well-defined around slowly growing tumors and barely detectable around fast-growing, aggressive tumors.

Latent benign bone tumors are classified as stage 1. Such tumors usually are asymptomatic and commonly are discovered as an incidental radiographic finding. Their natural history is P.7 of slow growth, and in most cases, they heal spontaneously. These lesions never become malignant and usually heal following simple curettage. Examples include fibrous cortical defects and nonossifying fibromas (NOF) (FIG 6A).

FIG 6 • A. NOF of the distal femur (arrow). As in most cases of NOF, the lesion was asymptomatic, and the plain radiographs were ordered because of a trauma to the knee. Aneurysmal bone cyst of the distal tibia as seen by plain radiographs: anteroposterior (AP) (B) and lateral (C) views. Plain radiographs of benign GCT of the proximal tibia: AP (D) and lateral (E) views. The tumor had been neglected for 18 months and necessitated proximal tibia resection and reconstruction with endoprosthesis. (Courtesy of Martin M. Malawer.) Active benign bone tumors are classified as stage 2 lesions. These tumors grow progressively but do not violate natural barriers. Associated symptoms may occur. Curettage and burr drilling are curative in most cases (FIG 6B-E). Aggressive benign bone tumors (stage 3) may cause destruction of surrounding bone and usually break through the cortex into the surrounding soft tissues. Local control can be achieved only by curettage and meticulous burr drilling with a local adjuvant such as liquid nitrogen, argon beam laser, or phenol. Wide resection of the lesion with a margin of normal tissue (FIG 6D,E) is another option.

EVALUATION OF THE PATIENT WITH A MUSCULOSKELETAL LESION Presenting Symptoms Bone sarcomas typically present with pain that starts out as intermittent and progresses to a constant pain. Night pain often is a component. Pain typically is deep-seated and dull and may resemble that of a toothache. Patients with high-grade tumors present with a history of several months of pain. Patients with low-grade tumors, by contrast, present with a history of mild pain, typically lasting more than half a year. Local soft tissue swelling is common. STS can arise anywhere in the body, but the lower extremities are the most common site. The incidence is as follows: Lower extremities: 46% Trunk: 19% Upper extremities: 13% Retroperitoneum: 12% Head and neck: 9% Other locations: 1% The presenting symptoms and signs of STS are nonspecific. These lesions commonly present as a painless, slow-growing mass, but in 20% of patients, they present as a painful, rapidly growing mass.

Physical Examination Patients with suspected musculoskeletal tumors should be examined thoroughly. The affected site is inspected for soft tissue mass or swelling, overlying skin changes, lymphadenopathy, neurologic deficit, and vascular deficiency.

Imaging and Other Staging Studies Plain Radiography Plain radiographs remain key in imaging bone tumors. Based on medical history, physical examination, and plain P.8 radiographs, bone tumors can be diagnosed accurately in over 80% of cases. Because of the fine trabecular detail revealed by plain radiographs, bone lesions of the extremities can be detected at an earlier stage; lesions of the spine and pelvis, however, are not diagnosed until a large volume of bone has been destroyed. Plain radiographs can show the location of the tumor in the bone, cortical destruction and thickening, periosteal response to the tumor (eg, Codman triangle, sunburst), type of matrix produced by the tumor (osteoid, chondroid, fibrous), and soft tissue calcifications. Computed Tomography Computed tomography (CT) is the imaging modality of choice to evaluate the extent of bone destruction. CT should be performed on a helical scanner that enables improved two-dimensional images and threedimensional (3-D) reconstruction capability. The field of view should be small enough to allow adequate

resolution, particularly of the lesion and the adjacent neurovascular bundle and muscle groups. A slice thickness of 1 mm or less through the tumor enables accurate 3-D reconstructions. Intravenous contrast dye should be employed to demonstrate the anatomic relation between the tumor and arterial vessels and to enhance soft tissue tumors, unless there is a clear contraindication for its use.

FIG 7 • A. 3-D CT angiogram. This is a new technique for evaluating the relation between bone tumors and the adjacent arteries. This radiograph demonstrates the relationship of the popliteal artery and trifurcation to a posterior tibial OS. Note the relation of the vessels to the tumor. B. CT scan showing lung metastases. C,D. Primary lymphoma of the distal femur. Plain radiographs suggest cortical integrity. This is confirmed by axial CT (E) and T2-weighted MRI (F), which demonstrates the intraosseous extent of the tumor. (continued)

FIG 7 • (continued) G. MRI of a large thigh, high-grade (stage IIB) STS. The thigh is the most common site for extremity STS. MRI evaluation is the most useful study in determining the extent of STS. H. Bone scan of a proximal humeral (right) OS. I. Limb-sparing surgery for a proximal humeral OS. The defect was reconstructed by a modular segmental prosthesis. J. Extensive GCT of the proximal tibia. Angiography performed prior to a proximal tibia resection documented an absent peroneal artery. A successful effort was made to preserve the anterior tibial artery during the resection; otherwise, the leg would have been dependent on a single vessel. K. Angiogram of a distal femoral (diaphyseal) OS following induction chemotherapy. Note that the tumor is avascular. The decrease of tumor vascularity is an extremely reliable finding in predicting tumor necrosis. L. Gross specimen of a diaphyseal OS following resection and induction chemotherapy. There was 100% tumor necrosis. M. Axillary venogram showing venous occlusion. Venography is especially useful in evaluating tumors of the pelvis and shoulder girdle. (C-F,J: Courtesy of Martin M. Malawer.) A 3-D CT reconstruction with intravenous contrast accurately demonstrates blood vessels that are likely to be distorted or, less commonly, incorporated directly into the tumor mass. This information helps the surgeon plan the anatomic approach and gauge the likelihood that a major blood vessel has to be resected en bloc with the

tumor (FIG 7A). Chest CT is the modality of choice when evaluating the patient for metastatic lung disease for both preoperative staging and postoperative follow-up (FIG 7B). P.9 P.10 Magnetic Resonance Imaging Magnetic resonance imaging (MRI) has been proven to be superior to CT in the evaluation of the intramedullary and extraosseous soft tissue extent of bone tumors (FIG 7C-F) and STS. Anatomic location and relation of the tumor can be defined accurately because the signal intensity of a tumor is assessed by comparing it with that of the adjacent soft tissues, specifically skeletal muscle and subcutaneous fat. MRI also make it possible to view a lesion in all three planes (ie, axial, sagittal, and coronal). Contrast-enhanced MRI is useful in evaluating the relation between a tumor and the adjacent blood vessels and in characterizing cystic lesions. The anatomic relation between the tumor and peripheral nerves may be assessed. The presence of orthopaedic hardware or surgical clips is not a contraindication to the performance of MRI; however, if a lesion is immediately adjacent to the location of the hardware, the local field may be distorted. MRI can accurately diagnose a variety of soft tissue tumors, including lipomas, liposarcomas, synovial cysts, pigmented villonodular synovitis, hemangiomas, and fibromatoses. Hematomas often have a characteristic appearance on MRI; however, high-grade sarcomas that have undergone significant intratumoral hemorrhage may resemble hematomas (FIG 7G). For this reason, the diagnosis of a simple hematoma should be made cautiously, and, once it is made, close clinical monitoring must be made until the condition has been resolved. The general guidelines regarding narrowing of the field and recommended number of slices per tumor are similar to those for CT. MRI allows accurate evaluation of the medullary extent of bone tumors to determine the level of bone resection with safe but narrow margins. Bone Scan Bone scan currently is used to determine the presence of metastatic and polyostotic bone disease and the involvement of a bone by an adjacent STS. This modality is more sensitive than plain radiographs for identifying bone lesions (FIG 7H,I). The appearance of a bone lesion in the flow and pool phases of a three-phase bone scan reflects its biologic activity and may be helpful in differentiating between benign and malignant lesions. This feature is known as tumor blush. Malignant tumors show uptake in the late flow phase. Response to chemotherapy can be evaluated by comparing the tumor blush before and after neoadjuvant chemotherapy. Other Studies Angiography Angiography is useful in demonstrating arterial displacement and occlusion, which are common in tumors that have a large extraosseous component. It also can detect vascular anomalies (FIG 7J) and establish patency of collateral vessels. Proximal femur resection, for example, often necessitates ligation of the profundus femoral artery (PFA). A patent superficial femoral artery (SFA) must be documented by

angiography prior to surgery; otherwise, the extremity will suffer severe ischemia following ligation of the PFA. CT angiography is an emerging modality that will likely replace angiography in preoperative tumor evaluation. Preoperative embolization may be useful in preparing for resection of metastatic vascular carcinomas if an intralesional procedure is anticipated. Metastatic hypernephroma is an extreme example of a vascular lesion that may bleed extensively and cause exsanguination without prior embolization. Serial angiographs may demonstrate reduced tumor vascularity as a result of chemotherapy treatment. Such a reduction has been shown to indicate a good response to preoperative chemotherapy (FIG 7K-L). Venography Contrast venography demonstrates partial occlusion or complete obliteration of major veins as a result of direct tumor invasion or indirect compression by the tumor mass. Venography is used for direct assessment of deep vein thrombosis. Venography also can indirectly assess tumor invasion into major nerves that lie in close proximity. Axillary tumors often are found to have invaded the brachial plexus when venography shows axillary vein occlusion (FIG 7M). Positron emission tomography (PET) CT PET is a functional diagnostic imaging technique that provides very different information from that obtainable with other imaging modalities. The most widely used radiotracer is F-18 fluoro-2-deoxy-D-glucose (FDG), which is an analog of glucose. The FDG uptake in cells is directly proportional to glucose metabolism, which is increased many times in malignant cells. FDG-PET now is the standard of care in initial staging, monitoring the response to therapy, and management of various cancers (eg, breast cancer, lung cancer, lymphoma). The introduction of combined PET-CT scanners, which provide not only functional but also structural information leading to a detection of subcentimeter lesions, has made this technique useful in the early detection of the disease process and in decreasing false-positive lesions. The FDG uptake is measured in standardized uptake value units, quantifying uptake and thereby differentiating malignant disease from other possible causes such as inflammatory or infectious processes. FIG 8 summarizes the use of the various imaging modalities in the staging process of a primary bone sarcoma.

Biopsy The concept and practice of biopsy of musculoskeletal tumors are discussed in Chapter 2.

Laboratory Studies Laboratory studies often are nonspecific. For patients younger than 40 years of age, they include a complete blood count with differential, peripheral blood smear, and erythrocyte sedimentation rate. Patients older than 40 years also need blood calcium and phosphate levels, serum and urine electrophoresis, and urinalysis. Serum alkaline phosphatase levels in primary OSs correlate with disease prognosis; therefore, pretreatment levels should be recorded. P.11

FIG 8 • Schematic of preoperative imaging studies for bony sarcomas. Bone scans, CT, MRI, and angiography are routinely required. (Courtesy of Martin M. Malawer.)

Formulating an Initial Assessment Age of the patient In younger patients (10 to 25 years), the common malignant bone tumors are OS, Ewing sarcoma, and leukemia. The common benign bone tumors are enchondroma, fibrous dysplasia, and eosinophilic granuloma. In the older age groups (40 to 80 years), the common malignant bone tumors are metastatic bone disease, myeloma, and lymphoma. Anatomic location of the tumor within the bone. Certain lesions have a predilection for occurring at particular locations: Adamantinoma: in the tibia Chondroblastoma: in the epiphysis of long bones Giant cell tumor (GCT): in the metaphysis and extending through the epiphysis to lie just below the cartilage, typically around the knee OS: in the metaphysis of the distal femur or proximal tibia Parosteal OS: in the distal femur (posterior cortex) Chondrosarcoma: in the pelvis Chordoma: in the sacrum Synovial sarcoma: in the foot and ankle Enchondroma and metastatic lung carcinoma: in the fingers

The effect of the lesion on the bone High-grade lesions spread rapidly, causing early cortical bone destruction and expansion. The typical lytic appearance is permeative or moth-eaten. Low-grade tumors spread at a slower pace but may still destroy cortical bone and produce a soft tissue mass. The response of the bone to the lesion High-grade lesions spread rapidly and give the bone little ability to contain the process. Cortical destruction, periosteal elevation (eg, Codman triangle, onion skin appearance), and soft tissue spread (sunburst appearance) often are seen. Matrix production Osteoid mineralization often is cloudlike and is typical of bone-forming tumors. Cartilage calcification often appears stippled and is characteristic of cartilage-forming tumors. Fibrous-forming tumors have a typical “ground-glass” appearance.

SURGICAL MANAGEMENT Classification of Surgical Procedures Four basic types of excisions are used, each of which is based on the relation between the dissection plane and the tumor and its pseudocapsule: intralesional, marginal, wide, and radical excisions (FIG 9). An intralesional excision is performed within the tumor mass and results in removal of only a portion of the tumor; the pseudocapsule and macroscopic tumors are left behind. In a marginal excision, the dissection plane passes through the pseudocapsule of the tumor. Such a resection may leave microscopic disease. Wide (en bloc) excision entails removal of the tumor, its pseudocapsule, and a cuff of normal tissue surrounding the tumor in all directions. This is the desired resection margin for sarcoma; however, the adequate thickness of the normal tissue cuff is a matter of some controversy. For both soft tissue and bone sarcomas, it generally is believed to be between 0.5 and 2 cm. Radical excision involves removal of the tumor and the entire anatomic compartment within which it arises. Although traditionally mentioned as the fourth excision type, it does not define the component of the tumor that is left behind. In other words, a radical excision can achieve a marginal or a wide margin, depending on how close the tumor is to the border of the compartment. However, radical excision excludes the possibility of skip metastases. P.12

FIG 9 • A. Multiple excision types for STS. B. Various excision types for bone sarcoma. (Courtesy of Martin M. Malawer.) In general, benign bone tumors are adequately treated by either an intralesional procedure (eg, curettage and burr drilling, cryosurgery) or by marginal excision. Primary bone sarcomas are treated with wide excision. Metastatic tumors are treated according to the general intent of the surgery. When a palliative surgery is performed, metastatic lesions are treated by an intralesional procedure. If a curative procedure is performed, as in the case of solitary breast metastasis, for example, the lesion is treated as if it was a primary bone sarcoma (ie, wide excision). Successful limb-sparing surgery consists of three phases: Resection of tumor. Resection follows the principles of oncologic surgery strictly. Avoiding local recurrence is the criterion of success and the main determinant of the amount of bone and soft tissue to be removed. Skeletal reconstruction. The average skeletal defect following adequate bone tumor resection measures 15 to 20 cm. Techniques of reconstruction (eg, prosthetic replacement [FIG 10], arthrodesis, allograft, or combination) vary and are independent of the resection, although the degree of resection may favor one technique over the other. Soft tissue and muscle transfers. Muscle transfers are performed to cover and close the resection site and to restore lost motor power. Adequate skin and muscle coverage is mandatory to decrease postoperative morbidity.

Guidelines for Surgical Resection The major neurovascular bundle must be free of tumor. Wide resection of the affected bone with a normal muscle cuff in all directions should be achieved. All previous biopsy sites and all potentially contaminated tissues should be removed en bloc. Bone should be resected 2 to 3 cm beyond abnormal uptake as determined by bone scan or MRI scan which indicates the level of marrow change by the tumor. (This is a safe margin to avoid intraosseous tumor extension.) The adjacent joint and joint capsule should be resected. Adequate motor reconstruction must be accomplished by regional muscle transfers. Adequate soft tissue coverage is needed to decrease the risk of skin flap necrosis and secondary infection.7

MALIGNANT BONE TUMORS Primary malignancies of bone arise from mesenchymal cells (sarcoma) and bone marrow cells (myeloma and lymphoma). Bone also is a common site of metastasis from a variety of carcinomas. OS and Ewing sarcoma, the most common malignant mesenchymal bone tumors, usually occur during childhood and adolescence. Other mesenchymal tumors (eg, MFH, fibrosarcoma, chondrosarcoma), while occasionally seen in childhood, are more common in adults. Multiple myeloma and metastatic carcinoma typically increase in frequency with increasing patient age and usually are seen in patients older than 40 years of age. This section describes the clinical, radiographic, and pathologic characteristics and treatment of the primary bone sarcomas. OS provides the model on which treatment of all other sarcomas is based. The effectiveness of multiagent chemotherapy regimens has been proven with the increase in overall survival rates from the bleak statistic of 15% to 20% with surgery alone in the 1970s to 55% to 80% today. In parallel with improved survival, dramatic advances in reconstructive surgery have made it possible for limb salvage to supplant amputation as the standard method of treatment.

Osteosarcoma OS is the most common primary bone sarcoma. OS is a high-grade malignant spindle cell tumor arising within a bone. Its distinguishing characteristic is the production of “tumor” osteoid, or immature bone, directly from a malignant spindle cell stroma. OS typically occurs during childhood and adolescence. In patients older than the age of 40 years, it usually is associated with a preexistent disease such as Paget disease, irradiated bones, multiple hereditary exostosis, or polyostotic fibrous dysplasia. The incidence of OS peaks to 8 per million per year between the ages of 10 and 20 years. Survival of OS patients has P.13 improved greatly over the past 30 years. The 5-year survival rate is 60%, except in patients older than the age of 45 years, where it is 40%.

FIG 10 • A. Various modular prostheses for limbsparing surgeries. B-D. Arthrodesis for a proximal tibial OS. B. Plain radiograph. C. Intraoperative photograph. D. Radiograph of a patient with 30 years follow-up following arthrodesis. (A: Courtesy of Stryker Orthopaedics, Inc., Mahwah, NJ.) The most common bone sites are the knee joint (50%) and the proximal humerus (25%). Between 80% and 90% of OSs occur in the long tubular bones; the axial skeleton rarely is affected (FIG 11). Pain, accompanied by a tender soft tissue swelling, is the most common complaint on presentation, with a firm, soft tissue mass fixed to the underlying bone found on physical examination. Systemic symptoms are rare. The incidence of pathologic fractures is less than 1%. Radiographic Characteristics Typical radiographic findings include increased intramedullary sclerosis due to tumor bone or calcified cartilage, an area of radiolucency due to nonossified tumor, a pattern of permeative destruction with poorly defined borders, cortical destruction, periosteal elevation, and extraosseous extension with soft tissue ossification. This combination of characteristics is not seen with any other lesion. Three broad categories are based on radiographic evaluation (FIG 12A-C): sclerotic OS (32%), osteolytic OS (22%), and mixed (46%). Although there is no statistically significant difference among overall survival rates of these types, it is important to recognize the patterns. The sclerotic and mixed types offer few diagnostic problems. Errors of diagnosis most often occur with pure osteolytic tumors. The differential diagnosis of osteolytic OS includes GCT, aneurysmal bone cyst, fibrosarcoma, and MFH.

FIG 11 • Skeletal locales of osteogenic sarcoma. P.14

FIG 12 • The three radiographic matrix types of OS: osteolytic (A; arrowheads indicate tumor), mixed (B), and sclerosing (C). There is no prognostic difference in survival based on the radiographic type of matrix formation. D. Classical high-grade OS reveals a population of pleomorphic spindle cells intimately associated with a mesh of immature lacy osteoid. The amount of osteoid can be minimal, or it may be a predominant element forming wide intersecting trabeculae lined by the malignant osteoblasts. Giant cells also can be present. E. Pathologic specimen. High-grade OS of the proximal humerus with cortical breakthrough and tumor extension into the soft tissues. F. CT scan demonstrating a large pelvic OS. (A-E: Courtesy of Martin M. Malawer.) P.15 Microscopic Characteristics The diagnosis of OS is based on the following findings: Identification of a malignant stroma that produces unequivocal osteoid matrix. The stroma consists of a haphazard arrangement of highly atypical cells. Pleomorphic cells that contain hyperchromatic, irregular nuclei. Mitotic figures, often atypical, usually are

easy to identify. Between these cells is a delicate, lacelike eosinophilic matrix, assumed to be malignant osteoid (FIG 12D). The predominance of one tissue type in many OSs has led to a histologic subclassification of this neoplasm. The term osteoblastic osteosarcoma is used for those tumors in which the production of malignant osteoid prevails. Calcification of the matrix is variable. Some tumors reveal a predominance of malignant cartilage production; hence, they are referred to as chondroblastic osteosarcoma. Even though the malignant cartilaginous elements may be overwhelming, the presence of a malignant osteoid matrix warrants the diagnosis of OS. Yet another variant is characterized by large areas of proliferating fibroblasts, arranged in intersecting fascicles. Such areas are indistinguishable from fibrosarcoma, and thorough sampling may be necessary to identify the malignant osteoid component. As the neoplasm permeates the cortex, the periosteum may be elevated. This stimulates reactive bone formation and accounts for a distinctive radiologic feature called Codman triangle. Longitudinal sectioning of the involved bone often reveals wide extension within the marrow cavity. Rarely, skip areas within the medullary canal can be demonstrated. There may be necrotic and hemorrhagic foci. At the time of diagnosis, most tumors already have caused substantial cortical destruction. Continued tumor growth results in involvement of the adjacent soft tissues (FIG 12E). Natural History and Chemotherapy Prior to the development of adjuvant chemotherapy, effective treatment was limited to radical margin amputation. Metastasis to the lungs and other bones generally occurred within 24 months. Overall survival rates 2 years after surgery ranged from 5% to 20%.10 No significant correlation between overall survival and histologic subtypes, tumor size, patient age, or degree of malignancy was seen. The most significant clinical variable was anatomic site: pelvic and axial lesions had a lower survival rate compared with extremity tumors, and tibial lesions had a better survival rate than femoral lesions (FIG 12F). The dismal outcome associated with OS has been altered dramatically by adjuvant chemotherapy and also by aggressive thoracotomy for pulmonary disease. No difference in local recurrence or overall survival was seen between patients undergoing amputation and those undergoing limbsparing surgery. Overall Treatment Strategy The patient with a primary tumor of the extremity without evidence of metastases requires surgery to control the primary tumor and chemotherapy to control micrometastatic disease. From 80% to 90% of all patients with OS fall into this category. Chemotherapy protocols typically have included various combinations and dosage schedules of high-dose methotrexate (HDMTX), doxorubicin hydrochloride (Adriamycin), and cisplatin. Ifosfamide, which is as effective as Adriamycin in single-agent studies, recently has supplanted methotrexate in many ongoing protocols. Multiagent chemotherapy using various dosing schedules is now considered standard treatment for OS. Success with adjuvant chemotherapy led to investigation of treatment in the neoadjuvant (preoperative) setting. When used in that setting, tumor response results in shrinkage of the soft tissue components, facilitating surgical excision and subsequent limb salvage. Tumor response is measured by tumor necrosis rate on microscopic pathology and is a significant prognostic factor. Limb salvage surgery is a safe surgical procedure for approximately 85% to 90% of patients. This technique may be used for all spindle cell sarcomas, regardless of histogenesis. The majority of OSs can be treated

safely by a limb-sparing resection combined with effective adjuvant treatments. The successful management of localized OS and other sarcomas requires careful coordination and timing of staging studies, biopsy, surgery, and preoperative and postoperative chemotherapy, radiation therapy, or both. The site of the lesion is evaluated as previously described. Preoperative studies allow the surgeon to understand the local anatomy and the volume of tissue to be resected and reconstructed. Surgery alone results in a cure rate of 15% to 20% at best. The choice between amputation and limb-sparing resection must be made by an experienced orthopaedic oncologist, taking into account tumor location, size, or extramedullary extent; the presence or absence of distant metastatic disease; and patient factors such as age, skeletal development, and lifestyle preference that might dictate the suitability of limb salvage or amputation. Routine amputations are no longer performed; all patients should be evaluated for limb-sparing options. Intensive, multiagent chemotherapeutic regimens have provided the best results to date. Patients who are judged unsuitable for limb-sparing options may be candidates for presurgical chemotherapy; those with a good response may then become suitable candidates for limb-sparing operations. The management of these patients mandates close cooperation between chemotherapist and surgeon. Variants of Osteosarcoma There are 11 recognizable variants of the classic OS. OS arising in the jaw bones is the most common of these. Parosteal and periosteal OS are the most common variants of the classic OS occurring in the extremities. In contrast to classic OS, which arises within a bone (intramedullary), parosteal and periosteal OS arise on the surface (juxtacortical) of the bone. Parosteal OS Parosteal OS is the most common of the unusual variants, representing about 4% of all OSs. Parosteal OS is a distinct variant of OS. Its prevalence is estimated to be 4%. It arises from the cortical bone and generally occurs in an older age group and has a better overall prognosis than OS. As in OS, the distal femur is the most common location; characteristically, the tumor attaches to its posterior aspect (FIG 13A-C). The proximal humerus and the proximal tibia are the next most common sites. P.16

FIG 13 • A. Gross specimen of a resection of a distal femoral OS. The average bony defect is 15 to 20 cm. Note how the biopsy site is removed en bloc with the tumor. The proximal tibia routinely is removed en bloc. The length of bone resected is determined by preoperative CT and MRI evaluation. B. CT scan of a typical parosteal OS. C. Gross specimen of a distal femoral parosteal OS. There is minimal intraosseous extension. D,E. Plain radiographs of the distal femur, AP (D) and lateral (E) views, show a dense, irregular, sclerotic lesion, attached to the posterior femoral cortex. The posterior aspect of the distal femur is a classic location for parosteal OSs and that diagnosis should be considered for any sclerotic lesion in that location. F. The relation of the parosteal OS to the medullary canal is better viewed on this CT scan, which shows no tumor extension to the canal. In contrast to osteochondromas, the medullary canal of the bone is not contiguous with that of the tumor. G. Gross pathologic specimen. H. Specimen shown illuminated with tetracycline fluorescence, which demonstrates minimal medullary tumor extension through the posterior cortex. I. Parosteal OS. There are parallel or intersecting osseous trabeculae (arrows) that may be either lamellar or woven-type bone matrix. The intervening fibrocollagenous tissue is composed of bland, widelyspaced fibroblastic cells. (D-I: Courtesy of Martin M. Malawer.)

P.17 Parosteal OSs usually present as a mass, occasionally associated with pain. The natural history is slow growth and late metastasis. The long-term survival rate is 75% to 85%. The tumor arises from the cortical surface and presents as a protuberant multinodular mass. The surface of the lesion may be covered in part by a cartilaginous cap resembling an osteochondroma; other areas may infiltrate into the adjacent soft tissues. The tumor usually encircles, partially or completely, the shaft of the underlying bone. In contrast to osteochondromas, the medullary canal of the bone is not contiguous with that of the neoplasm. Radiologically, parosteal OS presents as a large, dense, tabulated mass that is broadly attached to the underlying bone without involvement of the medullary canal (FIG 13D,E). If present long enough, the tumor may encircle the entire bone. The periphery of the lesion typically is less mature than the base. Despite careful evaluation, intramedullary extension is difficult to determine from plain radiographs. It is more accurately detected with CT scan. Diagnosis of parosteal OS, more than that of other bone tumors, must be based on the clinical, radiologic, and pathologic findings (FIG 13F-H). Most parosteal OSs are low grade; they do not require neoadjuvant and adjuvant chemotherapy and are best treated with wide excision. This tumor commonly is mislabeled by inexperienced clinicians and pathologists as osteochondroma, myositis ossificans, or conventional OS. In the classic low-grade lesion, irregularly formed osteoid trabeculae, usually of woven bone, are surrounded by a spindle cell stroma containing widely spaced, bland-appearing fibroblastic spindle cells (FIG 13I). There may be foci of atypical chondroid differentiation. With the higher grades, the likelihood of intramedullary involvement is increased. This, in turn, correlates well with the presence of distant metastases.

Chondrosarcomas (Central and Peripheral) Clinical Characteristics and Physical Examination Half of all chondrosarcomas occur in persons older than the age of 40 years. The most common sites are the pelvis, femur, and shoulder girdle. The clinical presentation varies. Peripheral chondrosarcomas may become quite large without causing pain, and local symptoms develop only because of mechanical irritation. Pelvic chondrosarcomas often are large and present with referred pain to the back or thigh, sciatica secondary to sacral plexus irritation, urinary symptoms from bladder neck involvement, unilateral edema due to iliac vein obstruction, or as a painless abdominal mass. Conversely, central chondrosarcomas present with dull pain. A mass is rarely present. Pain, which indicates active growth, is an ominous sign of a central cartilage lesion. This cannot be overemphasized. An adult with a plain radiograph suggestive of a “benign” cartilage tumor but who is experiencing pain most likely has a chondrosarcoma (FIG 14A). Radiographic Findings Central chondrosarcomas have two distinct radiologic patterns.4 One is a small, well-defined lytic lesion with a narrow zone of transition and surrounding sclerosis with faint calcification. This is the most common malignant bone tumor that may appear radiographically benign (FIG 14B,C). The second type has no sclerotic border and is difficult to localize. The key sign of malignancy is endosteal scalloping. This type is difficult to diagnose on plain radiographs and may go undetected for a long period of time. Peripheral chondrosarcoma is easily recognized as a large mass of characteristic calcification protruding from a bone. Correlation of the clinical, radiographic, and histologic data is essential for accurate diagnosis and evaluation of the aggressiveness of cartilage tumor. In general, proximal or axial location, skeletal maturity,

and pain point toward malignancy, even though the cartilage may appear benign. Grading and Prognosis Chondrosarcomas are graded 1, 2, and 3; most are either grade 1 or grade 2. The metastatic rate of moderate grade versus high grade is 15% to 40% versus 75%.3 Grade 3 lesions have the same metastatic potential as OSs.9 In general, peripheral chondrosarcomas are a lower grade than central lesions. Ten-year survival rates among those with peripheral lesions are 77% and 32% among those with central lesions. Secondary chondrosarcomas arising from osteochondromas (FIG 14D,E) also have a low malignant potential; 85% are grade 1. The multiple forms of benign osteochondromas or enchondromas have a higher rate of malignant transformation than the corresponding solitary lesions. The pelvis, shoulder girdle, and ribs are the most common sites of malignant transformation of osteochondromas. The risk of malignant transformation is approximately 20% to 25%. Microscopic Characteristics The histologic spectrum of chondrosarcomas varies tremendously. High-grade examples are easy to identify, whereas certain low-grade tumors are exceedingly difficult to distinguish from chondromas. Correlation between the histologic features (FIG 14F) and both the clinical setting and the radiographic changes is, therefore, of utmost importance in avoiding serious diagnostic error. The grade of malignant cartilaginous tumors correlates with clinical behavior. Grade 1 tumors are characterized by an increased number of chondrocytes set in a matrix that is chondroid to focally myxoid. Areas of increased cellularity with more marked variation in cell size, significant nuclear atypia, and frequent pleomorphic forms define a grade 2 lesion. Binuclear forms are more common in this group. Grade 3 chondrosarcomas, which are relatively uncommon, show even greater cellularity, often with spindle cell areas, and reveal prominent mitotic activity. Chondrocytes may contain large, bizarre nuclei. Areas of myxoid change are common.

Treatment The treatment of chondrosarcoma is surgical removal. Guidelines for resection for high-grade chondrosarcomas are similar to those for OSs. The sites of origin and the fact that chondrosarcomas tend to be low grade often make them amenable to limb-sparing procedures. The four most common sites are the pelvis, proximal femur, shoulder girdle, and diaphyseal portions of the long bones. P.18

FIG 14 • A. Pelvic CT scan of a patient with multiple hereditary exostosis. Note the large chondrosarcoma in the left hip and a normal-appearing osteochondroma in the right hip. The pelvis, shoulder girdle, and ribs are the most common sites of malignant transformation of osteochondromas. The risk of malignant transformation is approximately 20% to 25%. B-D. Secondary low-grade chondrosarcomas, arising from osteochondromas of the proximal humerus (B), proximal femur (C), and proximal tibia (D; arrowheads point to the region of the cartilage cap that has undergone malignant transformation). E,F. Secondary chondrosarcoma arising from the left proximal femur in a patient with multiple hereditary enchondromatosis. E. Plain radiograph shows a large, benign-appearing enchondroma arising from the right proximal femur and a large, poorly demarcated cartilage tumor, arising from the left. F. CT shows a marked difference between the two lesions. The destructive neoplastic tissue has completely replaced the enchondroma on the left, and it is almost fungating through the skin. The patient underwent modified hemipelvectomy and remains disease-free after more than 10 years of follow-up. (B-F: Courtesy of Martin M. Malawer.)

Variants of Chondrosarcoma

There are three less-common variants of classic chondrosarcoma. Each is briefly described in the following text (FIG 15). Clear cell chondrosarcoma, the rarest form of chondrosarcoma, is a slow-growing, locally recurrent tumor resembling a chondroblastoma but with some malignant potential that typically occurs in adults. The most difficult clinical problem is early recognition; it often is confused with chondroblastoma. Metastases occur only after multiple local recurrences. Primary treatment is wide excision. Systemic therapy is not required. Mesenchymal chondrosarcoma is a rare, aggressive variant of chondrosarcoma characterized by a biphasic histologic pattern, that is, small, compact cells intermixed with islands of cartilaginous matrix. This tumor has a predilection for P.19 P.20 flat bones; long tubular bones rarely are affected. It tends to occur in the younger age group and has a highmetastatic potential. The 10-year survival rate is 28%. This type responds favorably to radiation therapy.

FIG 15 • A,B. Plain radiographs of the proximal tibia: AP and lateral views show a central chondrosarcoma

(arrows). Macrosections of central chondrosarcomas of the proximal tibia (C) and proximal femur (D). E. Plain radiograph of the femoral shaft shows a central chondrosarcoma, presenting as a well-defined lytic lesion with a sharp transition zone, calcifications, and endosteal scalloping. Immunohistochemical stains, differentiation among these tumors has become simpler. F. Cross-section of an intramedullary chondrosarcoma discloses its lobular architecture and translucent, hyaline-like matrix. Note the characteristic endosteal erosions (arrows). G. Low-grade chondrosarcoma maintains a lobular architecture. There is slightly increased cellularity, occasional binucleate cells, and nuclear atypia. These cells typically are found in lacunae. The tumor tends to permeate between the normal osseous trabeculae. H. The juxtaposition of high-grade spindle sarcoma with lobules of low-grade chondrosarcoma is the hallmark of dedifferentiated chondrosarcoma. The spindle cell component usually reveals features of MFH, OS, or it may be unclassifiable. This neoplasm pursues an aggressive clinical course with very low long-term survival. (Courtesy of Martin M. Malawer.) Dedifferentiated chondrosarcoma. About 10% of chondrosarcomas may dedifferentiate into either a fibrosarcoma or an OS.3,9 They occur in older individuals and often are fatal. Surgical treatment is similar to that described for other high-grade sarcomas. Adjuvant therapy is warranted.

Ewing Sarcoma Ewing sarcoma is the second most common bone sarcoma of childhood; it is approximately one-half as common as OS. The lesion is characterized by poorly differentiated, small, round cells with marked homogeneity. The exact cell of origin is unknown. These mesenchymal cells are rich in glycogen and typically manifest a unique reciprocal chromosomal translocation, t(11;22)(q24;q12) that results in a chimeric protein, EWS/FLI-1. This translocation occurs in approximately 90% of these tumors. The clinical and biologic behavior is significantly different from that of spindle cell sarcomas. Within the past two decades, the prognosis of patients with Ewing sarcomas has been improved dramatically thanks to a combination of adjuvant chemotherapy, improved radiation therapy techniques, and the select use of limited surgical resection. Clinical Characteristics and Physical Examination Ewing sarcomas tend to occur in young children, although rarely in those younger than 5 years. The flat and axial bones are involved in 50% to 60% of cases. When a long (tubular) bone is involved, it most often is the proximal or diaphyseal area that is affected (FIG 16). In contrast, OSs occur in adolescence (average age, 15 years), most often around the knees, and involve the metaphysis of long bones.

FIG 16 • A. CT scan of a Ewing sarcoma of the scapula demonstrating a large soft tissue component. Ewing sarcomas often have a large soft tissue component, especially when a flat bone is involved. B. Gross photograph of a Ewing sarcoma of the scapula following resection. Note the large soft tissue extension both anterior and posterior to the glenoid. C. Ewing sarcoma belongs to the ever-expanding category of small, round, blue cell tumors. It is composed of round cells with scanty cytoplasm and round to oval nuclei. The nuclear chromatin tends to be fine and homogeneous. Differentiation from the other members of the round cell family may require the use of immunohistochemistry, electron microscopy, and cytogenetic and oncogene markers. (Courtesy of Martin M. Malawer.) Another unique finding with Ewing sarcomas is systemic signs, that is, fever, anorexia, weight loss, leukocytosis, and anemia.3 All may be a presenting sign of the disease and are seen in 20% to 30% of patients; this is in contrast to the distinct absence of systemic signs with OS until late in the disease process. The most common complaint is pain or a mass. Localized tenderness often is present with associated erythema and induration. These findings, in combination with systemic signs of fever and leukocytosis, closely mimic those of osteomyelitis. Radiographic Findings Ewing sarcoma is a highly destructive radiolucent lesion without evidence of bone formation. The typical pattern consists of a permeative or moth-eaten destruction associated with periosteal elevation. Multilaminated periosteal elevation (onion skin appearance) or a sunburst appearance is characteristic. When Ewing sarcoma occurs in flat bones, however, these findings usually are absent. Tumors of flat bones appear as a destructive lesion with a large soft tissue component. The ribs and pelvis are involved most often. Pathologic fractures occur secondary to extensive bony destruction and the absence of tumor matrix. The differential diagnosis is osteomyelitis, osteolytic OS, metastatic neuroblastoma, and eosinophilic granuloma. Natural History Ewing sarcoma is highly lethal and disseminates rapidly. Historically, fewer than 10% to 15% of patients

remained disease free at 2 years.3 Many patients present with metastatic disease. The most common sites for metastases are other bones and the lungs. P.21 Ewing sarcoma once was thought to be a multicentric disease because of the high incidence of multiple bone involvement. Unlike other bone sarcomas, Ewing sarcoma is associated with visceral, lymphatic, and meningeal involvement, and all of these areas must be investigated. Radiographic Evaluation and Staging No general staging system for Ewing sarcoma exists. The musculoskeletal staging system does not apply to the round cell sarcomas of the bone. Because these lesions have a propensity to spread to other bones, bone marrow, the lymphatic system, and the viscera, evaluation is more extensive than that for spindle cell sarcomas. It must include a careful clinical examination of regional and distal lymph nodes and radiographic evaluation for visceral involvement. Liverspleen scans and bone marrow aspirates are required in addition to CT of the lungs and the primary site. Angiography is required only if a primary resection is planned. Microscopic Characteristics Because accurate pathologic interpretation often is difficult, and bone heating is subject to several potential problems, the following guidelines have been established for the biopsy of suspected round cell tumors: Adequate material must be obtained for histologic evaluation and electron microscopy. Routine cultures should be made to aid in the differentiation from osteomyelitis. Biopsy of the bony component is not necessary. The soft tissue component usually provides adequate material. Bone biopsy should be through a small hole on the compressive side of the bone. Pathologic fracture through an irradiated bone often does not heal. Large nests and sheets of relatively uniform round cells are typical. The sheets often are compartmentalized by intersecting collagenous trabeculae. The cells contain round nuclei with a distinct nuclear envelope. Nucleoli are uncommon, and mitotic activity is minimal. Occasional rosette-like structures may be found, although neuroectodermal origin has never been confirmed. In the vicinity of necrotic tumor, small pyknotic cells may be observed. Vessels in these necrotic regions often are encircled by viable tumor cells. The cells often contain cytoplasmic glycogen. This neoplasm belongs to the category of small, blue round cell tumors, a designation that also includes neuroblastoma, lymphoma, metastatic OS, and, occasionally, osteomyelitis and histiocytosis. When confronted with this differential diagnosis, the pathologist may turn to electron microscopy or immunohistochemistry for additional information. Combined Multimodality Treatment Ewing sarcomas generally are considered radiosensitive. Radiation therapy to the primary site has been the traditional mode of local control. Within the past decade, surgical resection of selected lesions has become increasingly popular. Although detailed management is beyond the scope of this chapter, the following sections summarize some common aspects of the multimodality approach. Chemotherapy Doxorubicin, actinomycin D, cyclophosphamide, and vincristine are the most effective agents. A variety of

different combinations and schedules are used. All patients require intensive chemotherapy to prevent dissemination. Overall survival in patients with lesions of the extremities now ranges between 40% and 75%. Radiation Therapy Radiation must be administered to the entire bone at risk. The usual dose is 4500 to 6000 cGy, delivered over 6 to 8 weeks. To reduce the morbidity of radiation, it is recommended that between 4000 and 5000 cGy be delivered to the whole bone, with an additional 1000 to 1500 cGy given to the tumor site. Surgical Treatment The role of surgery in the treatment of Ewing sarcoma currently is changing. The Intergroup Ewing's Study recommends surgical removal of “expendable” bones such as the ribs, clavicle, and scapula. In general, surgery is reserved for tumors located in high-risk areas, for example, the ribs, ilium, and proximal femur. Risk is defined as an increased incidence of local recurrence and metastases. In general, surgery is considered an adjunct to the other treatment modalities. Interest recently has increased in primary resection of Ewing sarcoma following induction (neoadjuvant) chemotherapy, similar to the treatment of OS. When this resection is performed, radiation therapy is not given if the surgical margins are negative (ie, wide resection). The goal of this approach is to increase local control as well as minimize the complications and functional losses that are associated with high-dose radiation therapy given to a young patient.

Giant Cell Tumor of Bone GCT of bone is a benign aggressive, locally recurrent tumor with a low metastatic potential (4% to 8%). Giant cell sarcoma of bone refers to a de novo, malignant GCT, not to the tumor that arises from the transformation of a GCT previously thought to be benign. These two lesions are separate clinical entities. Clinical Characteristics and Physical Examination GCTs occur slightly more often in females than in males. Eighty percent of GCTs in the long bones occur after skeletal maturity; 75% of these develop around the knee joint. A joint effusion or pathologic fracture, uncommon with other sarcomas, is common with GCTs. GCTs occasionally occur in the distal radius, the vertebrae (2% to 5%), and the sacrum (10%).3 Natural History and Potential Malignancy Although GCTs rarely are malignant de novo (2% to 8%), they may undergo transformation and demonstrate malignant potential histologically and clinically after multiple local recurrences. Between 8% and 22% of known GCTs become malignant following local recurrence.3 This rate decreases to less than 10% if patients who have undergone radiation therapy are excluded. Approximately 40% of P.22 malignant GCTs become malignant at the first recurrence. The remainder typically become malignant by the second or third recurrence; thus, each recurrence increases the risk of malignant transformation. A recurrence after 5 years is extremely suspicious for a malignancy. Primary malignant GCT generally has a better prognosis than does secondary malignant transformation of typical GCT, especially if the transformation occurs after radiation therapy. Local recurrence of a GCT is determined by the adequacy of surgical removal rather than by histologic grade. Radiographic and Clinical Evaluation

GCTs are eccentric lytic lesions without matrix production occurring at the end of long bones. About 10% are axial. They have poorly defined borders with a wide area of transition. They are juxtaepiphyseal with a metaphyseal component. Although the cortex is expanded and appears destroyed, at surgery, it usually is found to be attenuated but intact. Periosteal elevation is rare; soft tissue extension is common. In the skeletally immature patient, GCT must be differentiated from aneurysmal bone cyst, although both lesions are closely related. GCTs are classified as type I, II, or III using the Enneking staging system. Microscopic Characteristics Two basic cell types constitute the typical GCT. The stroma is characterized by polygonal to somewhat spindled cells containing central round nuclei. Benign, multinucleated giant cells are scattered diffusely throughout the stroma. Small foci of osteoid matrix, produced by the benign stroma cells, can be observed; however, chondroid matrix never occurs.

Treatment Treatment of GCT of bone is surgical removal. In general, curettage of the bony cavity with “cleaning” of the walls with a high-speed burr drill and the use of a physical adjuvant will kill any cells remaining within the cavity wall. We prefer the combined use of cryosurgery (either liquid nitrogen or a closed system of argon and helium) to obtain temperatures of -40 °C. The cavity is then reconstructed with bone graft, polymethylmethacrylate, and internal fixation devices, which permit early mobilization. Cryosurgery has been used with more success for GCTs than for any other type of bone tumor. Cryosurgery is effective in eradicating the tumor while preserving joint motion and avoiding the need for resection or amputation. Liquid nitrogen is a very effective physical adjuvant and is recommended following curettage resection. Curettage alone is not recommended because of the associated high rate of local recurrence.

COMMON SOFT TISSUE SARCOMAS Treatment The treatment of high-grade STS has undergone fundamental changes within the past decade. Treatment of these patients requires a multimodality approach, and successful management requires cooperation among the surgeon, medical oncologist, and radiation oncologist. The appropriate role of each modality is continuously changing, but general descriptions are provided in the following sections.

Chemotherapy The impact of chemotherapy for high-grade STS on survival remains controversial. Combination chemotherapy has been shown to be more effective than single-agent therapy in preventing pulmonary dissemination from high-grade sarcomas. The most effective drugs in use today are doxorubicin hydrochloride (Adriamycin) and ifosfamide. Dacarbazine, methotrexate, and cisplatin also have activity against these tumors and are included in many current protocols. The various combinations traditionally are given in an adjuvant (postoperative) setting and are presumed effective against clinically undetectable micrometastases. Neoadjuvant (preoperative) chemotherapy is being evaluated in several institutions. Early results have indicated that significant reduction in tumor size can occur, thereby facilitating attempts at limb salvage. In patients with tumors deemed unresectable who are therefore destined for limb amputation, the tumors

may shrink drastically in response to preoperative chemotherapy, thereby making them candidates for wide resection and limb-sparing surgery.

Radiation Therapy Radiation typically is administered in a dose of 5000 to 6500 cGy over many fractions. This modality is effective in an adjuvant setting in decreasing local recurrence following nonablative resection. The degree to which the initial surgical volume should be decreased in these circumstances is controversial, although the rate of local recurrence following a wide excision and postoperative radiation therapy is 5% to 10%. Radiation therapy includes irradiating all the tissues at risk, shrinking fields, preserving a strip of unirradiated skin, and using filters and radiosensitizers. Local morbidity has been greatly decreased within the past decade. Preoperative radiation is effective in reducing tumor volume but is associated with increased morbidity resulting from significant wound-healing complications and, therefore, is not recommended as often as postoperative radiation.

Surgery Removal of the tumor is necessary to achieve local control, by either a nonablative resection (limb salvage) or an amputation. The procedure chosen depends on results of the preoperative staging studies. A prospective randomized National Cancer Institute (NCI) trial established that a multimodality approach employing limb salvage surgery combined with adjuvant radiation and chemotherapy offered local control and survival rates comparable to those of amputation plus chemotherapy while simultaneously preserving a functional extremity. The use of adjuvant therapy (chemotherapy or radiation) permits limb-sparing procedures for most extremity STS. Enneking et al5,6 have shown that a radical resection for an STS has a local recurrence rate of about 5% with surgery alone. Wide excision (without adjuvant radiation or chemotherapy) has a 50% rate of local failure. Results from the NCI showed that the rate of local recurrence decreased to 5% following local excision (either a marginal or wide excision) when combined with postoperative radiation therapy and chemotherapy. Others have reported similar good results from preoperative radiation, with or without preoperative P.23 chemotherapy. Contraindications to limb-sparing surgery are similar to those for the bony sarcomas. In general, nerve or major vascular involvement is a contraindication. Studies of referred patients show that approximately half of all patients with STS treated with attempted excisional biopsy by the referring surgeon will have microscopic or gross tumor remaining. As a result, referred patients undergo routine re-resection of the surgical site to ensure adequate local control prior to institution of adjuvant treatment.

GENERAL SURGICAL TECHNIQUE AND CONSIDERATIONS All tissue at risk should be removed with a wide, en bloc excision that includes the tumor, a cuff of normal muscle, and all potentially contaminated tissues. It is not necessary to remove the entire muscle group. The biopsy site should be removed with 3 cm of normal skin and subcutaneous tissue en bloc with the tumor. The tumor or pseudocapsule should never be visualized during the procedure (FIG 17). Contamination of the wound with tumor greatly increases the risk of local recurrence. Distant flaps should not be developed at the time of resection. This may contaminate a noninvolved area.

The margin surrounding the surgical wound should be marked with metallic staples to help the radiotherapist determine the high-risk area if radiation treatment is needed later. Reconstruction of the defect should include local muscle transfers to protect exposed neurovascular bundles and bone cortex. All dead space should be closed, and there should be adequate drainage to prevent hematoma. Perioperative antibiotics should be given. These procedures have a low but significant rate of postoperative infection. The risk of infection following preoperative adjuvant therapy is particularly high.

Undifferentiated Pleomorphic Sarcoma Undifferentiated pleomorphic sarcoma (UPS) is the most common STS in adults. UPSs are a heterogeneous collection of poorly differentiated sarcomas, many of which can be specifically classified with the application of DNA and protein analysis. It most commonly affects the lower extremity and has a predilection for originating in deep-seated skeletal muscles.

FIG 17 • Gross specimen of a STS arising within the anterior compartment of the leg treated by an amputation. Note the relation to the adjacent bone and related vessels of the popliteal (arrows) trifurcation. The reactive zone and pseudocapsule are shown. The tumor usually presents as a multinodular mass with wellcircumscribed or ill-defined infiltrative borders. The size and location at the time of diagnosis often correlate with the ease of clinical detection: Superficial variants, presenting as dermal or subcutaneous masses, may be only a few centimeters in diameter, whereas those arising in the retroperitoneum often attain a diameter of 15 cm or more. Color and consistency vary considerably and reflect, in part, the cellular composition. Red-brown areas of hemorrhage and necrosis are not uncommon. The myxoid variant of UPS contains a predominance of grayish white, soft, mucoid tumor lobules, created by the high content of myxoid ground substance.

About 5% of UPSs undergo extensive hemorrhagic cystification termed telangiectatic transformation, leading to a clinical and radiologic misdiagnosis of hematoma. A needle biopsy can result in a benign diagnosis if only the hemorrhagic center of the tumor is sampled. For these reasons, until proven otherwise, one should assume that an underlying STS is present in any adult patient with a deep-seated hematoma that does not resolve after a few weeks, even when there is a history of trauma to that site. The currently accepted broad histologic spectrum of UPS encompasses many variants that formerly were considered distinct clinicopathologic entities. These lesions, which had been named according to the predominant cell type, include fibroxanthoma, malignant fibroxanthoma, inflammatory fibrous histiocytoma, and GCT of soft parts. Immunohistochemical studies and electron microscopy can assist in the accurate diagnosis of a significant percentage of these tumors. The basic neoplastic cellular constituents of all fibrohistiocytic tumors include fibroblasts, histiocyte-like cells, and primitive mesenchymal cells (FIG 18). Both an acute and a chronic inflammatory cell component usually are present as well. The proportion of these malignant and reactive cell elements, the degree of pleomorphism of the neoplastic cells, and the predominant pattern account for the wide histologic variances. The histologic pattern most commonly associated with UPS is a storiform arrangement of the tumor cells, which is characterized by fascicles of spindle cells that intersect to form a “pinwheel” or “cartwheel” pattern (see FIG 18). Atypical and bizarre giant cells, often containing abnormal mitotic figures, may be present. The histologic grade (almost always intermediate to high) is a good prognosticator of metastatic P.24 disease. In the myxoid variant, the second most common histologic type, the tumor cells are dispersed in a richly myxoid matrix. The less common giant cell type (malignant giant cell of soft parts) is characterized by abundant osteoclast-like giant cells that are diffusely distributed among the malignant fibrohistiocytic elements.

FIG 18 • MFH, a high-grade sarcoma, is characterized by pleomorphic spindle cells forming fascicular or typical storiform patterns. Bizarre tumor giant cells are interspersed. (Courtesy of Martin M. Malawer.)

We recently analyzed our data of 150 UPS lesions. Our 5-year survival rates were 74%, the distant recurrence rate was 28%, and the local recurrence rate was 19%. A local recurrence, large tumor size, deep tumors, close margins, and proximal location in the extremity were found to have a significant negative prognostic influence on survival.

Liposarcoma Liposarcoma is the second most common STS in adults. It has a wide range of malignant potential that correlates well with the histologic classification of the individual tumor. The lower extremity is the most common site and accounts for over 40% of all cases. These tumors, particularly those arising in the retroperitoneum, can attain enormous size; specimens measuring 10 to 15 cm and weighing more than 5 kg are not uncommon (FIG 19A). Liposarcomas tend to be well circumscribed and multilobulated. Gross features usually correlate with the histologic composition. Well-differentiated liposarcomas contain variable proportions of relatively mature fat and fibrocollagenous tissues; vary from yellow to grayish white; and can be soft, firm, or rubbery. A tumor that is soft, is pinkish tan, and has a mucinous surface probably is a myxoid liposarcoma, the most common histologic type. The high-grade liposarcomas (ie, round cell and pleomorphic) vary from pinkish tan to brown and may disclose extensive hemorrhage and necrosis. Identification of typical lipoblasts is mandatory to establish the diagnosis of liposarcoma. This diagnostic cell contains one or more round, cytoplasmic fat droplets that form sharp, scalloped indentations on the central or peripheral nucleus. Well-differentiated liposarcomas often contain a predominance of mature fat cells and only a few, widely scattered lipoblasts. Inadequate sampling can, therefore, lead to a misdiagnosis of a benign lipoma (FIG 19B). Well-differentiated liposarcomas that arise in the superficial soft tissues have been called atypical lipomas. In the sclerosing variant of a well-differentiated liposarcoma, delicate collagen fibrils that encircle fat cells and lipoblasts make up a prominent part of the matrix. Treatment with wide excision and adjuvant radiation therapy is recommended only if marginal margins were achieved. We treat high-grade liposarcomas like any other high-grade STS, with neoadjuvant chemotherapy, wide excision, and adjuvant chemotherapy. Radiation therapy is indicated if wide margins were not achieved.

FIG 19 • A. Large, low-grade liposarcoma of the posterior thigh. B. The diagnosis of a well-differentiated liposarcoma depends on the identification of characteristic lipoblasts. These cells can be mono- or multivacuolated with hyperchromatic, scalloped nuclei. This variant can closely mimic ordinary lipoma. (Courtesy of Martin M. Malawer.) Sixty-five percent of liposarcomas arise in the extremities; the remaining 35% arise in the retroperitoneum. Negative prognostic factors for survival are retroperitoneal location, tumor size greater than 10 cm, and locally recurrent disease at initial presentation.

Synovial Sarcoma

Synovial sarcoma is the fourth most common STS. In spite of its name, this tumor rarely arises directly from a joint but, rather, arises in proximity to it, with a propensity for the distal portion of the extremities. Synovial sarcomas occur in a younger age group than do most other sarcomas: Most patients are younger than the age of 40 years. Typical findings of synovial sarcoma include a painful mass, soft tissue calcifications on radiography, and a malignant tumor of the foot. The tumor typically presents as a deep-seated, wellcircumscribed, multinodular, firm mass. Contiguity with a synovium-lined space is rare, and, occasionally, lymphatic spread occurs. Unlike most STS, synovial sarcomas may be present as a painless mass for a few years. Plain radiographs often show small calcifications within the mass. That finding should alert the physician to the diagnosis. Virtually, all synovial sarcomas are high grade. These poorly differentiated neoplasms usually present as illdefined, infiltrative lesions with a soft, somewhat gelatinous consistency. The classic histologic presentation of this tumor is a biphasic pattern, which implies the presence of coexisting but distinct cell populations, namely, spindle cells and epithelioid cells (FIG 20A). The plump spindle cells, usually the predominant component, form an interlacing fascicular pattern that is reminiscent of fibrosarcoma. Within the spindle cell portion of the tumor, areas resembling the acutely branching vascular pattern of hemangiopericytoma are common. The arrangement of epithelioid cells varies, ranging from merely solid nests to distinct, gland-like structures (FIG 20B). When they compose glandular spaces, the constituent cells range from cuboidal to tall columnar; they rarely undergo squamous metaplasia. Histochemical stains demonstrate that the P.25 glandular lamina contain epithelial-type acid mucins. The neoplasm may contain extensive areas of dense stromal hyalinization, and focal calcification is common. The presence of extensive areas of calcification, sometimes with modulation to benign osteoid, deserves recognition because this rare variant imparts a significantly more favorable prognosis than that for other forms of synovial sarcoma.

FIG 20 • A. Synovial sarcoma is characterized by a distinctive biphasic pattern that implies an admixture of spindle cell areas along with epithelioid cells forming gland-like structures. The proportions of these two components are variable. B. When only one of the elements of synovial sarcoma is present—almost invariably the spindle cell component—it is termed monophasic synovial sarcoma. (Courtesy of Martin M. Malawer.) The existence of a monophasic spindle cell synovial sarcoma has been recognized, although distinguishing it from fibrosarcoma can be difficult. In contrast to fibrosarcoma, the spindle cell variant of synovial sarcoma may contain cytokeratins, as demonstrated with immunohistochemical studies.

REFERENCES 1. American Cancer Society. Bone cancer: key statistics. American Cancer Society Web Site. Available at:

http://www.cancer.org/cancer/bonecancer/detailedguide/bone-cancer-key-statistics. Revised April 21, 2014. Accessed June, 2014. 2. American Cancer Society. Cancer Facts & Figures 2013. Atlanta, GA: American Cancer Society, 2013:1013. Available at: http://www.cancer.org/acs/groups/content/@epidemiologysurveilance/documents/document/acspc036845.pdf. Accessed June, 2014. 3. Dahlin DC. Bone Tumors: General Aspects and Data on 6,221 Cases, ed 3. Springfield, IL: Charles C Thomas, 1978. 4. Edeiken J. Bone tumors and tumor-like conditions. In: Edeiken J, ed. Roentgen Diagnosis and Disease of Bone. Baltimore: Williams & Wilkins, 1981:30. 5. Enneking WF, Spanier SS, Goodman MA. A system for the surgical staging of musculoskeletal sarcoma. Clin Orthop Relat Res 1980;153:106-120. 6. Enneking WF, Spanier SS, Malawer MM. The effect of the anatomic setting on the results of surgical procedures for soft parts sarcoma of the thigh. Cancer 1981;47:1005-1022. 7. Malawer M, Sugarbaker PH, eds. Musculoskeletal Cancer Surgery: Treatment of Sarcomas and Allied Diseases. Dordrecht: Kluwer Academic Publishers, 2000. 8. Mankin HJ, Lange TA, Spanier SS. The hazards of biopsy in patients with malignant primary bone and soft-tissue tumors. J Bone Joint Surg Am 1982;64:1121-1127. 9. Marcove RC. Chondrosarcoma: diagnosis and treatment. Orthop Clin North Am 1977;8:811-820. 10. Marcove RC, Miké V, Hajek JV, et al. Osteogenic sarcoma under the age of twenty-one. A review of one hundred and forty-five operative cases. J Bone Joint Surg Am 1970;52:411-423. 11. Rougraff BT, Simon MA, Kneisl JS, et al. Limb salvage compared with amputation for osteosarcoma of the distal end of the femur. A long-term oncological, functional, and quality-of-life study. J Bone Joint Surg Am 1994;76:649-656. 12. Sim FH, Bowman W, Chao E. Limb salvage surgery and reconstructive techniques. In: Sim FH, ed. Diagnosis and Treatment of Bone Tumors: A Team Approach. A Mayo Clinic Monograph. Thorofare, NJ: Slack, 1983.

Chapter 2 Biopsy of Musculoskeletal Tumors Jacob Bickels Yair Gortzak Martin M. Malawer

BACKGROUND Biopsy is a fundamental step in the diagnosis of a musculoskeletal tumor. It should be regarded as the final diagnostic procedure, not as a mere shortcut to diagnosis. Biopsy should be preceded by careful clinical evaluation and analysis of the imaging studies.2,6,10,11 Diagnosis of a musculoskeletal lesion is based on this triad of clinical, pathologic, and imaging findings, and all three must coincide or else the diagnosis should be questioned.2,6 Most biopsies are technically simple to perform. Decisions regarding the indication for biopsy, the specific region of the lesion for biopsy, and the anatomic approach and biopsy technique, however, can make the difference between a successful biopsy and a catastrophe. A poorly performed biopsy could become an obstacle to proper diagnosis and may impede the performance of adequate and safe tumor resection. Biopsies executed in a referring institution rather than in a specialized oncology center were shown to be often associated with an unacceptably high rates of devastating complications, unnecessary amputations, and major errors in diagnosis.8,9

BIOLOGIC BEHAVIOR OF MUSCULOSKELETAL TUMORS Tumors arising in bone and soft tissues share characteristic patterns of biologic behavior, stemming from their common mesenchymal origin and anatomic environment. Those unique patterns form the basis of the staging system and current treatment strategies. Histologically, sarcomas are categorized as being low, intermediate, or high grade based on tumor morphology, extent of pleomorphism, atypia, mitosis, and necrosis. Grading represents their biologic aggressiveness and correlates with the likelihood of metastases.

FIG 1 • A cut through a high-grade soft tissue sarcoma showing its thin pseudocapsule composed of compressed tumor cells and a fibrovascular zone of reactive inflammatory response. Sarcomas form a solid mass that grows centrifugally with the periphery of the lesion being the least mature part. Unlike the true capsule that surrounds benign lesions, which is composed of compressed normal cells, sarcomas are generally enclosed by a reactive zone or pseudocapsule. This consists of compressed tumor cells and a fibrovascular zone of reactive tissue with a variable inflammatory component that interacts with the surrounding normal tissues (FIG 1). In addition, these cells may break through the pseudocapsule to form metastases (“skip metastases”) within the same anatomic compartment in which the lesion is located. By definition, these are locoregional micrometastases that have not passed through the circulation (FIGS 2,3 and 4). This phenomenon P.27 may be responsible for local recurrences that develop in spite of apparently negative margins after a resection. Although low-grade sarcomas regularly interdigitate into the reactive zone, they rarely form tumor skip nodules beyond that area.

FIG 2 • Growth pattern of bone and soft tissue sarcomas. Sarcomas grow in a centripetal fashion, with the most immature part of the lesion at the growing edge. A reactive zone is formed between the tumor and the compressed surrounding normal tissues and may be invaded by tumor nodules that represent microextensions of the tumor (satellites) and not a metastatic phenomenon. High-grade sarcomas may present with tumor nodules that grow outside the reactive zone (skip lesions) but within the same anatomic compartment in which the lesion is located. This finding is documented preoperatively in less than 5% of patients. (Reprinted from Bickels J, Jelinek JS, Shmookler BM, et al. Biopsy of musculoskeletal tumors: current concepts. Clin Orthop Relat Res 1999;368:212-219.)

FIG 3 • High-grade sarcomas may break through the pseudocapsule to form skip metastases within the same anatomic compartment. Skip metastases (arrows) from an osteosarcoma of the distal femur.

FIG 4 • A 40-year-old female who presented with a rapidly enlarging mass that had developed in her calf. Physical examination revealed a deep-seated, firm mass, 10 cm in diameter, located at the proximal aspect of the calf. MRI demonstrated the primary lesion (A) as well as additional two skip metastases in the substance of the soleus muscle (B). C,D. Angiogram of the lower extremity clearly shows all three lesions. (Reprinted from Bickels J, Jelinek JS, Shmookler BM, et al. Biopsy of musculoskeletal tumors: current concepts. Clin Orthop Relat Res 1999;368:212-219.) Sarcomas respect anatomic borders. Local anatomy influences tumor growth by setting natural barriers to extension of the lesion. In general, sarcomas take the path of least resistance and initially grow within the anatomic compartment in which they arose. In a later stage, the walls of that compartment (either the cortex of a bone or aponeurosis of a muscle) are violated, and the tumor breaks into a surrounding compartment (FIGS 5 and 6). Most bone sarcomas are bicompartmental at the time of presentation; they destroy the overlying cortex and extend directly into the adjacent soft tissues (FIG 7). Soft tissue sarcomas may arise between compartments (extracompartmental) or in an anatomic site that is not walled off by anatomic barriers such as the intermuscular or subcutaneous planes. In the latter case, they remain extracompartmental and only at a later stage do they break into the adjacent compartment (FIG 8). Carcinomas, on the other hand, directly invade the surrounding tissues, irrespective of compartmental borders (FIG 9). Unlike carcinomas, bone and soft tissue sarcomas disseminate almost exclusively through the blood. Hematogenous spread of extremity sarcomas is manifested by pulmonary involvement in the early stages and by bony involvement in later stages (FIG 10). P.28

FIG 5 • High-grade osteosarcomas of the distal femur (A), proximal tibia (B), and proximal femur (C) showing tumor extension to the articular cartilage, which remains intact. This phenomenon allows intra-articular resection in most cases of juxtaarticular sarcomas of bone.

FIG 6 • Extension of an osteosarcoma of the distal femur to the knee joint along the cruciate ligaments. The articular cartilage is intact. Knee joint extension of a high-grade sarcoma of the distal femur is a rare event, necessitating extra-articular resection (ie, en bloc resection of the distal femur, knee joint, and a component of the proximal tibia) as shown here.

FIG 7 • Plain radiograph (A) and magnetic resonance images (B,C) showing a classical osteosarcoma of the distal femoral metaphysic breaking through the medial cortex into the adjacent soft tissues. P.29

FIG 8 • Clinical photograph (A) and plain radiograph (B) showing neglected soft tissue sarcoma of the leg eroding through the overlying skin and into the underlying tibia, causing a pathologic fracture.

FIG 9 • A. Liposarcoma of the posterior thigh extending to the sciatic nerve. Although the patient presented with sciatic pain, there was a clear plane of dissection between the tumor capsule and the nerve. B. Metastatic carcinoma at the same anatomic location penetrating directly into the nerve and causing an intractable agonizing sciatic pain.

FIG 10 • Plain radiographs showing metastatic osteosarcoma to the lungs (A) and L3 (B) (arrows). P.30

DIAGNOSTIC STUDIES AND CONSIDERATIONS Biopsy of a musculoskeletal lesion should be performed only at the conclusion of staging, which is the process

that entails performing the imaging studies required to determine local tumor extension, its relation to adjacent anatomic structures, and presence of metastatic spread. Staging studies for a high-grade sarcoma of bone include computed tomography (CT) and magnetic resonance imaging (MRI) scans of the affected bone in order to evaluate the local tumor extent, and chest CT and positron emission tomography (PET) scan to rule out the presence of metastatic disease. The CT scan provides anatomic data on the extent of bone involvement, and the MRI scan provides data on tumor extent within the medullary canal and in the surrounding soft tissues. As such, these two imaging studies provide complementary information and are both required to evaluate the full anatomic extent of a given bone tumor. A PET scan using fluorine-18-fluorodeoxyglucose (PET-FDG) was shown to be as effective as the conventional imaging modalities in detecting the primary tumor and superior to them in detecting bone manifestations and lymph node involvement of the disease.12 However, PET-FDG was shown to be less accurate than CT in detecting lung metastases.12 Data obtained from the staging process allow the surgeon to determine the region of the tumor that represents the underlying pathology and to plan the surgical approach for the definitive resection.1 When appropriately analyzed and combined with results of clinical evaluation, these data allow accurate diagnosis in most musculoskeletal lesions prior to biopsy. Thus, lesions that appear to be benign clinically and radiologically do not need a biopsy. In contrast, benign aggressive, malignant, and questionable lesions do require a biopsy for confirmation of the clinical diagnosis and for accurate classification before initiating definitive treatment (FIG 11). A final and compelling reason for deferring biopsy until staging is completed is that biopsy superimposes both real and artificial radiologic changes at the biopsy site, which can alter the interpretation of the imaging studies.

FIG 11 • A. Osteochondroma of the distal femur and (B) deep lipoma of the shoulder. These lesions have typical findings on clinical examination and classical appearance on imaging studies, and biopsy is therefore not required for their diagnosis or for decision making regarding their management.

PREOPERATIVE PLANNING Anatomic Location of the Biopsy Tract The questions that must be answered before performing a biopsy are as follows: What part of the lesion needs to be biopsied? What is the safest anatomic route to that location? The position of the biopsy site within the lesion is of major significance because soft tissue and bone sarcomas may have regional morphologic variations. As a result of that heterogeneity, a considerable volume of tumoral tissue or multiple samples when needle biopsy is done are required to establish a diagnosis. The term sampling error refers to an incorrect or inconclusive diagnosis that occurs because the biopsy specimen had been taken from a region that does not represent the underlying primary disease. In contrast, carcinomas are commonly homogeneous and a single core biopsy or needle aspirate is usually sufficient for diagnosis. The periphery of soft tissue sarcomas usually authentically represents the underlying malignancy and it should be the target of biopsy. Performing a biopsy from the center of this type of lesion may result in ambiguous findings because these sites may contain mostly necrotic tissue and blood. Similarly, the extraosseous component of a malignant bone tumor is as representative of the tumor as is the bony component, and it should be biopsied if present. Violating the cortex of a bone that harbors a malignant tumor predisposes the patient to a pathologic fracture and is acceptable only if there is no extraosseous extension of the tumor. In planning the definitive surgery, it was traditionally assumed that the biopsy tract is contaminated with tumor cells and that it should therefore be resected with the same safety margins as the primary tumor (ie, wide margins). Binitie et al3 reported 59 adult patients who had a deep and large soft tissue sarcoma of the extremities and for which a core needle biopsy was done. Definitive surgery in these patients did not include the biopsy tract and there P.31 was no increase in local tumor recurrence in those study patients compared with previously published data on local tumor recurrence when the biopsy tract was removed en bloc with the tumor.3

FIG 12 • Pathologic evaluation of a biopsy tract, resected en bloc with metastatic melanoma of the distal humerus, showing a viable tumor focus. Kaffenberger et al7 reported similar observations among their 388 patients who underwent fine needle aspiration biopsy for high-grade sarcoma. A reasonable policy, therefore, would be to remove only the biopsy tracts that remain following an open biopsy (FIG 12). For these reasons, the surgeon performing the biopsy must be familiar with the planned surgical technique, whether it is limb-sparing surgery or amputation. Importantly, the biopsy incision and the tract to the tumor must all be made within the planned surgical incision site so that they will be removed en bloc with the surgical specimen (FIGS 13 and 14). Despite serious concerns regarding the potential of accelerated growth or metastatic dissemination of a malignant tumor after biopsy, there is no well-founded objective evidence that biopsy promotes either adverse event. The real risk of open and needle biopsies is that they may spread tumor cells locally and facilitate local tumor recurrence when performed inadequately.

Open versus Closed Biopsy

A closed biopsy does not involve an incision. The specimen is obtained after skin puncture by a needle or trephine. An open biopsy, in contrast, does require an incision. It can be either “incisional,” in which case only a representative specimen is removed from the lesion, or “excisional,” in which case the lesion is completely removed. Open incisional biopsy remains the most reliable diagnostic technique to which all other biopsy modalities should be compared. It allows the pathologist to evaluate cellular morphologic features and tissue architecture from different sites of the lesion. Furthermore, it provides material for performing ancillary studies, such as immunohistochemistry, cytogenetics, molecular genetics, flow cytometry, and electron microscopy. These studies may help in the diagnosis and subclassification of bone and soft tissue tumors and therefore guide the choice of definitive treatment. Open biopsies are criticized because of the increased risk of complications that may include iatrogenic injury to blood vessels or nerves, complicated wound healing, wound infection, and tumor cell contamination along the biopsy tract and subsequent local recurrence. Furthermore, open biopsies are associated with considerably higher cost of hospitalization and operating room time. Refined techniques and accumulated experience with the interpretation of material obtained from needle biopsies as well as the use of CT- or ultrasound-guided trephine biopsies have made it possible for the accurate diagnosis of most musculoskeletal lesions. Thus, guided needle biopsies have become the standard technique in most orthopaedic oncology centers.13,14 Fine needle aspirations were also shown to have similar reliability in allowing accurate diagnosis in the majority of patients who have high-grade sarcomas.5 Open biopsies may be unavoidable in cases when needle aspiration has not provided a clear diagnosis or in cases where the clinical-radiologic diagnosis is inconsistent with a known histologic entity.

FIG 13 • A. An open incisional biopsy scar overlying osteosarcoma of the distal femur. B. During tumor resection, the scar and the biopsy tract to the tumor are kept intact over the tumor. C. The surgical specimen with the biopsy tract.

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FIG 14 • A. Planned biopsy incision around the proximal humerus. Because most primary bone sarcomas extend into the surrounding soft tissues, the overlying muscle should be removed en bloc with the tumor. In this case, the deltoid muscle should be removed with the tumor and the biopsy tract should be included within the surgical specimen, indicating the choice of a transdeltoid approach through the anterior third of the muscle. The traditional deltopectoral approach for such a biopsy would necessitate a wider resection of the pectoralis major muscle, compromise its subsequent use for soft tissue reconstruction, and possibly contaminate the main neurovascular bundle of the upper extremity. B. Biopsy tracts around the proximal and distal femur. A distinction is made between lateral and medial lesions. C. Biopsy tracts around the proximal tibia. A distinction is made between lateral and medial lesions. (Reprinted from Bickels J, Jelinek JS, Shmookler BM, et al. Biopsy of musculoskeletal tumors: current concepts. Clin Orthop Relat Res 1999;368:212-219.) P.33

TECHNIQUES

▪ Biopsy After adequate planning of the biopsy tract, biopsy should be executed according to the following guidelines: Use the smallest longitudinal incision that is compatible with obtaining an adequate specimen. Transverse incisions are contraindicated because they will require a wider soft tissue resection at the time of definitive surgery (TECH FIG 1). When a purely intraosseous bone lesion is being biopsied, make a cortical window and carefully consider what its shape should be. Clark et al4 evaluated the impact of three types of biopsy hole shapes (rectangular hole with square corners, rectangular hole with rounded corners, and oblong hole with rounded ends) on the breaking strength of human femora. They found that an oblong hole with rounded ends afforded the greatest residual strength.4 They also demonstrated that increasing the width of the hole caused a significant reduction in strength but increasing the length did not.4 Therefore, when the biopsy must be taken from the bone, a small circular hole should be made so that only minimal stress risers are created. If a larger window is needed, an oblong shape should be preferred (TECH FIG 2). Obtain enough tissue and use a knife or curette to avoid crushing or distorting the specimen's texture. As a general rule, culture what you biopsy and biopsy what you culture. A frozen section may preclude the need for biopsy.

TECH FIG 1 • A. The smallest longitudinal incision that allows an adequate specimen to be obtained should be used. B. A transverse biopsy incision requires a longer and curved incision to allow its incorporation at

the time of the definitive resection. These incisions frequently cross tension lines, compromise the blood supply to the myocutaneous flaps, and potentially contaminate a larger surgical field. As a result, postoperative radiation therapy, when indicated, will be administered to a wider field. C. Open biopsy of a high-grade soft tissue sarcoma of the left buttock by means of a transverse incision. D. A long and curved incision was used at the time of the definitive surgery to allow adequate resection as well as subsequent closure of skin flaps. E. Axial T2-weighted magnetic resonance image of the proximal thigh showing a highgrade soft tissue sarcoma of the adductor compartment. F. Open biopsy was done using a long transverse incision. G. Intersecting long incisions were required at the time of definitive surgery to remove the biopsy site en bloc with the tumor. All compartments of the thigh were grossly contaminated with tumoral tissue. P.34

TECH FIG 2 • A. An oblong cortical window with rounded ends affords the greatest residual strength and is recommended for biopsy of purely intraosseous lesions. B. Biopsy of the femoral diaphysis through a large rounded cortical window. C. A fracture that occurred upon patient's mobilization in bed. (A: Reprinted from Bickels J, Jelinek JS, Shmookler BM, et al. Biopsy of musculoskeletal tumors: current concepts. Clin Orthop Relat Res 1999;368:212-219.)

TECH FIG 3 • A. A drain must be positioned in proximity to and parallel to the site planned for incision of the definitive procedure. B. Biopsy of the acetabulum for a high-grade osteosarcoma. The drain was positioned in the flank, causing considerable contamination of the ipsilateral pelvic girdle. (A: Reprinted from Bickels J, Jelinek JS, Shmookler BM, et al. Biopsy of musculoskeletal tumors: current concepts. Clin Orthop Relat Res 1999;368:212-219.) Hemostasis Use meticulous hemostasis. Any hematoma around a tumor should be considered contaminated. A large hematoma may dissect the soft and subcutaneous tissues and contaminate the entire extremity, making limb-sparing surgery impossible. A tourniquet is rarely indicated for an open biopsy because bleeding vessels cannot be observed and adequate hemostasis is hard to achieve. If a tourniquet is used, the limb should not be exsanguinated by wrapping with an Esmarch bandage because this may propel tumor cells to the proximal aspect of the extremity. To allow hemostasis, the tourniquet must be removed before wound closure. Use drains if necessary. The port of entry must be in proximity with and a continuation of the skin incision, not at an angle to its sides (TECH FIG 3).

PEARLS AND PITFALLS ▪ Biopsy must be preceded by tumor staging. ▪ Plan the biopsy site and tract according to the planned incision and tract of the definitive surgery. ▪ Use the smallest longitudinal incision for an open biopsy. ▪ The periphery of musculoskeletal tumors is preferable to a central site for biopsy.

▪ Obtain enough material and avoid crushing or distorting the specimen's texture. ▪ Culture what you biopsy and biopsy what you culture. ▪ Use meticulous hemostasis. ▪ When biopsy results do not match the results of clinical and radiologic evaluations, carefully reassess all three.

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REFERENCES 1. Anderson MW, Temple HT, Dussault RG, et al. Compartmental anatomy: relevance to staging and biopsy of musculoskeletal tumors. AJR Am J Roentgenol 1999;173:1663-1671. 2. Bickels J, Jelinek JS, Shmookler BM, et al. Biopsy of musculoskeletal tumors: current concepts. Clin Orthop Relat Res 1999;368:212-219. 3. Binitie O, Tejiram S, Conway S, et al. Adult soft tissue sarcoma local recurrence after adjuvant treatment without resection of core needle biopsy tract. Clin Orthop Relat Res 2013;471:891-898. 4. Clark CR, Morgan C, Sontegard DA, et al. The effect of biopsy hole shape and size on bone strength. J Bone Joint Surg 1977;59(A):213-217. 5. Fleshman R, Mayerson J, Wakely PE Jr. Fine needle aspiration biopsy of high-grade sarcoma: a report of 107 cases. Cancer 2007;111(6):491-498. 6. Jaffe HL. Introduction: problems of classification and diagnosis. In: Jaffe HL, ed. Tumors and Tumorous Conditions of the Bones and Joints. Philadelphia: Lea & Febiger, 1958:9-17. 7. Kaffenberger BH, Wakely PE Jr, Mayerson JL. Local recurrence rate of fine-needle aspiration biopsy in primary high-grade sarcomas. J Surg Oncol 2010;101(7):618-621. 8. Mankin HJ, Lange TA, Spanier SS. The hazards of biopsy in patients with malignant primary bone and soft tissue tumors. J Bone Joint Surg 1982;64A:1121-1127. 9. Mankin HJ, Mankin CJ, Simon MA. The hazards of biopsy, revisited. J Bone Joint Surg 1996;78A:656-63. 10. Peabody TD, Simon MA. Making the diagnosis: keys to a successful biopsy in children with bone and soft-tissue tumors. Orthop Clin North Am 1996;27:453-459. 11. Scarborough MT. The biopsy. Instr Course Lect 2004;53:639-644. 12. Völker T, Denecke T, Steffen I, et al. Positron emission tomography for staging of pediatric sarcoma patients: results of a prospective multicenter trial. J Clin Oncol 2007;25(34):5435-5441. 13. Yang YJ, Damron TA. Comparison of needle core biopsy and fine-needle aspiration for diagnostic

accuracy in musculoskeletal lesions. Arch Pathol Lab Med 2004;128:759-764. 14. Yao L, Nelson SD, Seeger LL, et al. Primary musculoskeletal neoplasms: effectiveness of core-needle biopsy. Radiology 1999;212: 682-686.

Chapter 3 Overview of Endoprosthetic Reconstruction Martin M. Malawer Kristen Kellar-Graney

BACKGROUND Limb salvage—reconstruction following resection of malignant tumors of the extremities—has seen dramatic advances in a relatively brief period of time. The traditional surgical approach to the treatment of sarcoma, namely immediate amputation of the extremity, was advocated in the early 1960s and 1970s to ensure local control of disease. Early pioneers in orthopaedic oncology worked diligently to define the optimal level of amputation and developed techniques to manage wounds of the pelvis and shoulder girdle following hind- or forequarter amputation. However, such aggressive surgical management failed to impact overall patient survival, with most patients dying of metastatic disease. Only after the introduction of effective doxorubicin- and methotrexate-based chemotherapy protocols in the early 1970s could alternatives to amputation be considered. A handful of surgeons began to challenge the orthodoxy of amputation in children and adults with bone sarcomas. Marcove, Francis, and Enneking were among the pioneers who developed the rationale and basic techniques used in limb-sparing surgery. The former two surgeons were the first in the United States to develop endoprosthetic replacements for tumor patients. Starting with a very few highly selected patients with extremity osteosarcoma, limb-sparing surgery now is a treatment option for most bone and soft tissue sarcomas not only of the extremities but of the pelvis and shoulder girdles as well. Today, over 90% to 95% of tumor patients may be expected to undergo successful limb-sparing procedures when treated at a major center specializing in musculoskeletal oncology. This dramatic alteration in patient care required significant advances along many fronts, including the following: Better understanding of tumor growth and metastasis Determination of appropriate surgical margins Use of effective induction (neoadjuvant or preoperative) chemotherapy Development of improved approaches, preserving soft tissue vascularity Deeper understanding of skeletal biomechanics Advanced material engineering and manufacturing techniques Development of inherently stable modular prostheses The chapters in this section outline in specific detail many of the surgical approaches and techniques of oncologic resection and reconstruction currently used by leaders in the field of orthopaedic oncology. The importance of meticulous surgical technique cannot be overstated because this is vital to ensure an optimal oncologic and functional outcome for the patient. A successful limb-sparing surgery consists of three interdependent stages performed in sequence: 1. Tumor resection with appropriate oncologic margins

2. Reconstruction and stabilization of the involved bone and joints 3. Restoration of the soft tissue envelope for prosthetic coverage and function.

History of Endoprosthetic Reconstruction Austin Moore and Harold Bohlman,9 in 1943, were the first to publish an example of endoprosthetic reconstruction for a bone tumor, consisting of a custom-designed Vitallium proximal femur used for a patient with a giant cell tumor of bone. In the early 1970s, Francis and Marcove ushered in the current age of endoprosthetic reconstruction by developing prostheses to replace the distal femur and the entire femur for reconstruction following radical resection of osteosarcomas8 (FIG 1). A major drawback for these custom implants quickly became evident: Each implant would take 6 to 12 weeks to manufacture, during which time the patient's tumor could progress significantly. This led to the development of the concept of induction (initially called preoperative or neoadjuvant) chemotherapy, in which the newly proven drugs doxorubicin and methotrexate were administered during the interval between diagnosis and delivery of the manufactured custom implant.10 Both of these drugs had just been shown to have activity against bone sarcomas. Induction chemotherapy has since been adopted in the management of an increasingly large variety of other cancers. As the demand for endoprosthetic reconstruction grew, a wide variety of custom implants became available from a number of orthopaedic manufacturers. Many of these early implants, however, suffered from design flaws and errors in manufacturing, resulting in significant problems with implant failures (FIG 2A). However, improved material and manufacturing techniques developed for the profitable and ever-expanding market for total joint replacements eventually were applied to these “mega” prostheses. The adoption of the rotating hinge for implants around the knee and bipolar heads for the hip followed successful use of these designs for total joint replacement. Although these advances significantly improved the performance of custom implants, problems with the time required for manufacturing and the lack of flexibility at the time of implantation hampered the widespread acceptance of custom endoprosthetic reconstruction. Manufacturers responded to this problem by incorporating the concept of modularity, adapting concepts and designs from modular total hip and knee prostheses to develop P.37 interchangeable and easily assembled endoprosthetic systems (FIG 2B,C). Although modularity increased the complexity of the mechanical construct and carried a risk of failure associated with the sum of all of the components, these potential problems were easily outweighed by significant benefits.

FIG 1 • The first known distal femoral replacement was performed in the United States, by Kenneth Francis, at New York University in 1973. A. Distal femoral osteosarcoma treated with doxorubicin prior to surgical resection. B. Cemented distal femoral replacement with long intramedullary stems. This prosthesis used a modified Walldius fixed knee hinge. C. Scan of the front page of a historic Journal of Bone and Joint Surgery article. Original publication of the first prosthesis performed in the United States. D. Original prosthesis implanted by Drs. Bohlman and Moore for fibrous dysplasia of the proximal femur. E. Custom segmental prosthesis used during 1980s prior to the development of the MRS by Howmedica, Inc. (Rutherford, NJ). (A,B: Courtesy of Martin M. Malawer; C: From Moore AT, Bohlman HR. Metal hip joint: a case report. J Bone Joint Surg Am 1943;25[3]:688-692.) The primary advantage of a modular endoprosthesis is the system's flexibility: The surgeon can concentrate on performing the best possible oncologic resection knowing that any changes in the preoperative plan can be accommodated by selecting those components that fit the patient's anatomy and actual skeletal defect optimally. Modular trial components allow the surgeon to mix and match pieces and test the reconstruction prior to selection and assembly of the actual final prosthesis. Standardization of components permits the implant manufacturer to increase the level of quality control

greatly while reducing the overall cost of manufacturing through economies of scale. Modular systems reduce overall inventory and time to delivery while providing a large choice of prosthetic shapes and sizes. Modular systems permit hospitals to maintain an on-site inventory that has allowed these systems to be available immediately as a backup option for selected nononcologic patients, such as those undergoing difficult joint revision surgery or patients with significant periarticular fractures. A first-generation modular endoprosthetic system was the Howmedica Modular Replacement System (HMRS; Howmedica International, Limerick, Ireland), designed and manufactured in Europe. This system featured intramedullary cementless press-fit stems supported by external flanges and cortical transfixation screws while the knee mechanism P.38 P.39 consisted of a simple hinge design. Although the system truly was modular, in clinical practice, the long-term outcomes were disappointing. Significant problems encountered with this device included aseptic stem loosening (osteolysis), substantial stress shielding with bone resorption, screw fracture and migration, and a polyethylene failure rate higher than 40% for the knee mechanism.4,6 Consequently, this system rarely was used in the United States.

FIG 2 • A. Examples of failed, retrieved, custom endoprosthetic implants used during the 1980s. The most common mode of mechanical failure was stem breakage or bending, typically due to small stem diameter or from stress risers caused by the sharp transition from the prosthetic body to the stem. B. Modular implant design featuring a Kinematic rotating hinge knee. Interchangeable components permit easy offthe-shelf flexibility in the operating room, allowing the implant to match the patient's anatomy. C. Intraoperative assembly of the prosthesis requires impaction of locking Morse tapers to connect the stem, body segments, and joint modules. (Courtesy of Martin M. Malawer.)

FIG 3 • Modular saddle prosthesis (Waldemar-Link) for reconstruction of acetabular defects. A. Originally designed for revision total hip surgery, modular components of increasing size permit reconstruction of the pelvis after periacetabular resection. The prosthesis consists of the saddle portion, which articulates with the ilium (1); the base element, which provides lateral offset and allows for rotation (2,3); and the femoral stem (4). B. Postoperative radiograph 9 months after partial pelvic resection demonstrating preservation of leg length. C. Custom distal femoral replacement used in 1982. D. Custom prosthesis (1984 to 1988) now incorporating a porous collar to permit extracortical bone fixation. E. Modular distal femoral replacement introduced in 1988, featuring interchangeable off-the-shelf components. This system, with minor modifications, is still in use today. (A,B: Courtesy of Martin M. Malawer.) An example of a second-generation modular system is the saddle endoprosthesis (Waldemar-Link Mark II Endo-Model Modular Saddle Prosthesis; Waldemar-Link, Hamburg, Germany; FIG 3A,B). This prosthesis, originally designed for the treatment of infected failed total hip replacements, was modified to allow for reconstruction of the hip following resection of the pelvis. The unique feature of this system is the saddle itself, which is a U-shaped component that straddles the ilium, allowing motion in flexion-extension and abduction-adduction in the anteroposterior and lateral planes against the bone. The saddle is attached with a rotating polyethylene-lined ring, increasing the degree of freedom and allowing

for hip rotation. These are attached to a series of interchangeable modular bodies that, in turn, connect to a standard cemented femoral stem. This device preserves limb length following resection of the periacetabulum (eg, type II pelvic resection, modified internal hemipelvectomy) while functioning like a total hip prosthesis. The clinical and functional results following saddle reconstruction of the pelvis with this system have been promising.1 The first successful universal modular system was introduced in 1988 as the Modular Segmental Replacement System (MSRS; Howmedica, Inc., Rutherford, NJ), renamed the Modular Replacement System (MRS) and now available as P.40 the updated Global Modular Replacement System (GMRS; Stryker/Howmedica, Inc., Mahwah, NJ; FIG 3C-E). This system was designed to provide modular replacements for the proximal humerus, proximal femur, total femur, distal femur, and proximal tibia and has been instrumental in the widespread adoption of endoprosthetic reconstruction following segmental bone resection. The growing popularity of endoprosthetic reconstruction has led to the introduction of similar modular systems from several orthopaedic manufacturers (eg, Orthopaedic Salvage System [Biomet, Warsaw, IN], Guardian Limb Salvage System [Wright Medical Technology, Arlington, TN]). Current implant manufacturers still offer customized solutions for challenging anatomic issues. However, these custom implants often consist of a custom module mated to an existing modular system to ensure maximal flexibility.

FIG 4 • Proximal femoral replacement. A. MRS proximal femoral replacement featuring porous coating and a lateral loop to facilitate reconstruction of the hip abductors. B. Postoperative radiograph demonstrating proximal femoral replacement following tumor resection. Note that bipolar arthroplasty of the hip is performed routinely to improve hip stability, and trochanteric reconstruction using a claw with cables is used to restore hip abduction. C. Periacetabular and proximal femoral replacement using a Howmedica customized pelvic replacement for osteosarcoma of the femoral head involving the hip joint. D. Intraoperative view showing cemented fixation of pelvic implant to iliac wing. E. Postoperative radiograph demonstrating restoration of leg length and lateralization of hip. (A,B: Courtesy of Martin M. Malawer.)

TYPES OF ENDOPROSTHETIC RECONSTRUCTION Specific anatomic examples of endoprosthetic reconstruction are discussed in the following paragraphs.

Hip Tumors involving the proximal femur are extremely common and include both primary sarcomas and metastatic carcinomas. Replacement of the proximal femur (FIG 4) is readily accomplished following resection of a

primary tumor or fracture through a subtrochanteric metastatic lesion. A bipolar hemiarthroplasty is used for the hip joint, with soft tissue reconstruction of the hip capsule to minimize the risk of dislocation.2 Reconstruction of the hip abductors is accomplished directly via laterally placed holes or loops or, if a portion of the trochanter was saved, by use of a trochanteric P.41 claw with cerclage cables. Less common are resections of the entire hip joint (ie, type II pelvic resection and its modifications). This defect can be reconstructed with a saddle prosthesis or with the recently designed partial pelvic implants that attach to the remaining ilium. Stability is achieved by balancing the muscle tension between the medial iliopsoas and the lateral hip abductors.

FIG 5 • Distal femoral replacement. A,B. Kinematic rotating hinge mechanism featuring an all-polyethylene tibial component permits a full range of flexion, rotation, and axial motion while restraining the knee in the anteroposterior and medial-lateral planes, respectively. C. Intraoperative view of distal femoral replacement after final assembly of the components. D,E. Distal femoral and proximal tibia MRS. This system permits reconstruction of several segments of various bones simultaneously if required. (A,B: Courtesy of Martin M. Malawer.)

Distal Femur The distal femur is the single most common site for primary bone sarcomas. Endoprosthetic reconstruction

(FIG 5) requires a unique combination of flexibility combined with overall stability because the knee capsule and the cruciate and collateral ligaments are removed during the resection. The Kinematic rotating hinge knee (GMRS) and similar partially constrained hinged designs permit substantial flexion-extension as well as rotation at the anatomic axis of the knee while providing inherent stability in the varus-valgus and anteriorposterior planes. Reconstruction of the extensor mechanism rarely is necessary because the patella often can be saved during the resection. Resurfacing of the patella is possible but often unnecessary.

Total Femur Patients presenting with extensive intramedullary tumors (eg, Ewing sarcoma or the rare diaphyseal osteosarcoma), as well as patients with multiple failed total joints and little remaining bone stock, can be treated with a total femoral replacement (FIG 6). Modular systems provide a readily available solution by combining distal femoral and proximal femoral components by means of interbody segments. This type of reconstruction has proven to be extremely durable because of the combination of the high degree of freedom associated with the two separate but related joints.

Proximal Tibia The tibia is anatomically unique in its anterior subcutaneous border and patellar tendon insertion. Routine use of a gastrocnemius rotation flap has dramatically reduced the incidence of postoperative complications, and compound reconstruction of the tendon insertion and careful attention to postoperative rehabilitation can result in minimal extensor lag. Joint stability at the knee is ensured by using the same rotating hinge design used for distal femoral replacements (FIG 7). P.42

FIG 6 • Total femoral replacement for osteosarcoma of the femur. A. Implant and trial components consist of a modular proximal femoral replacement connected to a modular distal femoral replacement of means of a maleto-male interbody segment. B. Postoperative radiograph demonstrating bipolar hip and rotating hinge joints. Meticulous soft tissue reconstruction of the extensor mechanism is crucial for the postoperative function of this prosthesis.

Proximal Humerus High-grade sarcomas of the proximal humerus require extra-articular resection, including the entire rotator cuff and deltoid muscles, to minimize the risk of local recurrence (FIG 8). Accordingly, ultimate functional outcome may be greatly restricted. A combination of static and dynamic suspension, including transfer of the pectoralis muscle, stabilizes the proximal humerus to the scapula, permitting painless and functional use of the elbow, wrist, and hand.

FIG 7 • Proximal tibial replacement for fibrosarcoma of bone. A. Assembled prosthesis, featuring a Kinematic rotating hinge knee and a resurfacing component of the distal femur. B. Intraoperative view showing final implant, with gastrocnemius flap being rotated for coverage of the implant and reinforcement of the patellar tendon reconstruction. C. Intraoperative photograph of a proximal tibia MRS replacement. D. Soft tissue reconstruction and reestablishment of the extensor mechanism. Medial gastrocnemius transfer to cover the prosthesis is an essential step in the reconstruction portion of the surgery. Low-grade tumors can be treated with intra-articular resections; preservation of the rotator cuff and deltoid can lead to function comparable to that provided by total shoulder replacements.

Scapula Following scapulectomy, endoprosthetic replacement of the scapula and glenohumeral joint lateralizes the humerus and improves stability and function of the shoulder (FIG 9). New scapular designs feature a locking articulation to improve stability, whereas use of a large-diameter Gore-Tex (W. L. Gore Ltd., Flagstaff, AZ) vascular graft to restore a joint capsule helps to ensure optimal stability. P.43

FIG 8 • Proximal humeral replacement. A. Trial and actual implants compared to resection specimen. B. Intraoperative view demonstrating use of multiple woven Dacron tapes for reattachment of the rotator cuff

tendons. As with proximal humeral replacement, ultimate functional outcome depends on the amount of muscle that can be preserved during the resection. Multiple muscle transfers are necessary to stabilize and power the prosthesis as well as to provide adequate coverage.

Elbow The elbow joint is not often affected by sarcomas or metastatic disease. Customized, hinged implants with small-caliber stems to fit the ulna can be used provided that sufficient soft tissue remains to cover the prosthesis. Function depends on preservation of the biceps insertion.

Total Humerus As with the total femur, the total humerus implant is a combination of a proximal humeral implant and an elbow replacement. Indications for this procedure are rare, but preservation of a sensate, functional hand remains superior to any amputation prosthesis.

FIG 9 • Total scapular replacement. A. Modular system composed of lightweight scapular body with locking mechanism that captures a proximal humeral implant. B. Intraoperative view of total scapular replacement demonstrating use of Gore-Tex graft for reconstruction of capsule around the interlocked joint. C. Postoperative radiograph of total scapular replacement. The prosthesis lateralizes the arm, helping to improve stability and function following resection. D. Newest version (third generation) of a “snap fit” scapula prosthesis, which is

mated to an MRS proximal humeral prosthesis. The use of a scapula prosthesis is functionally superior to the older technique of a “hanging” shoulder. E. Intraoperative reconstruction to stabilize a scapula prosthesis. The latissimus, rhomboids, deltoid, and trapezius muscles are required. Most shoulder girdle, axillary, and scapula tumors can be treated by a scapular prosthesis if the scapula is involved. (C: Courtesy of Martin M. Malawer; E: From Pritsch T, Bickels J, Wu CC, et al. Is scapular endoprosthesis functionally superior to humeral suspension? Clin Orthop Relat Res 2007;456:188-95.) P.44

FIG 10 • Intercalary replacement of the distal tibia for osteosarcoma using a customized Compress prosthesis. A. Preoperative radiograph. B. Intraoperative view showing the implant; muscle coverage was obtained using the tibialis anterior. C. Postoperative view showing position of implant. The short distal intramedullary stem is augmented with bone cement for secure fixation.

Calcaneus One case has been reported of a total calcaneal prosthesis implanted for osteosarcoma in lieu of a belowknee amputation. Ten years after surgery, the patient remained fully ambulatory without assistive devices.

Intercalary Endoprostheses

Replacement of the central portion of a long bone following diaphyseal resection for tumor has the significant advantage of preserving the patient's native adjacent joints in the humerus, femur, and tibia. Traditional implants limited the indication for this type of reconstruction due to the amount of remaining bone required to fix the prosthetic stems securely. Customized stems using crosspin fixation and the newer Compress fixation method (Biomet) have greatly expanded the indications for this procedure (FIG 10).

Expandable Implants for Skeletally Immature Patients Reconstruction of the axial skeleton in immature patients remains challenging (FIG 11). Children older than 10 to 12 years of age often can be treated similarly to adults using smaller versions of the modular prostheses, occasionally in combination with contralateral epiphysiodesis to equalize leg lengths at skeletal maturity. P.45 For children younger than 5 years of age, primary amputation remains the preferred solution, given the difficulty in obtaining a proper oncologic margin around the critical neurovascular bundles.

FIG 11 • Repiphysis expandable endoprosthetic replacement. A. Distal femoral replacement for osteosarcoma in a skeletally immature child. B. Expansion of implant is accomplished using an external radiofrequency (RF) coil placed around the implant. Induced heating of the prosthesis melts the inner plastic, allowing the compressed spring to expand; removal of the RF field allows the plastic to harden, locking the implant into place. C,D. Fluoroscopic views of the implant during expansion, demonstrating a 1-cm lengthening. Between these two age groups, reconstruction is feasible, but limb length inequality becomes functionally disabling as the child grows. Use of implants that can be expanded multiple times during growth permits prosthetic reconstruction for these children. These custom-created implants have been used in both the upper and lower extremity with mixed results as mechanical failures of the expansion mechanism is not uncommon. Whereas traditional expandable implants would require multiple invasive procedures to achieve expansion (with some patients undergoing 10 or more surgeries), the recently introduced custom Repiphysis noninvasive expandable implant (Wright Medical Technology) features a unique method of expansion that does not require surgery.

PATIENT SELECTION FOR ENDOPROSTHETIC RECONSTRUCTION Appropriate patient selection for limb-sparing surgery is essential to ensure optimal outcomes. Although the

introduction of effective chemotherapy for osteosarcoma was a major impetus in the development of limbsparing techniques, increasing patient survival has placed greater emphasis on functional outcome and durability of reconstruction. Patients expect solutions that address their functional, cosmetic, and psychological needs and demands and often reject the option of amputation. Although tumor size and location often are the determining factors in selecting patients for limb salvage, neoadjuvant (preoperative) chemotherapy may convert formerly unsalvageable patients to candidates for limbsparing procedures by inducing significant tumor response. Consequently, a complete reevaluation of the patient following neoadjuvant treatment is necessary before an appropriate surgical plan is selected. For appropriate patients, endoprosthetic reconstruction offers a durable and functional option for skeletal reconstruction. Limb-sparing procedures should not be limited to patients with favorable response to treatment. Patients with poor prognostic factors, such as metastatic disease at time of initial presentation or tumor growth during chemotherapy, often require surgery for local control of disease and palliation of symptoms such as pain. Although amputation may be necessary for some, limb-sparing surgery can avoid the significant psychological impact associated with mutilative procedures. Endoprosthetic reconstruction offers immediate stability and rapid mobilization while avoiding the need for prolonged bracing, crutches, or inpatient rehabilitation. The proven success and durability of endoprosthetic reconstruction has led to its adoption for other challenging, nontumorous conditions in which restoration of a segmental skeletal defect is required.7 For example, patients with multiple failed total joint replacements around the hip and knee may develop significant bone loss that cannot be corrected readily with traditional revision total joint components. In this subset of patients, resection of the failed prosthetic joint and removal of all devascularized bone followed by reconstruction with a “tumor” endoprosthesis can lead to significant functional recovery. Similarly, severely comminuted periarticular fractures not amenable to internal fixation can be addressed by removal of the fragmented bone and replacement with a segmental endoprosthesis. This procedure is extremely valuable for the obese, elderly patient with osteoporotic bone (often with significant medical comorbidities) who trips and falls on the knee, resulting in a type C distal femur (or, if a total knee replacement is in place, periprosthetic) fracture. Endoprosthetic reconstruction can be performed in a fraction of the time necessary for meticulous internal fixation, and because the prosthesis is inherently stable, the patient can begin immediate weight bearing without functional bracing.

GUIDELINES FOR ENDOPROSTHETIC RECONSTRUCTION Regardless of the anatomic location, certain basic principles apply to all endoprosthetic reconstructions. Restoration of the normal axis of motion and extremity length depends on component selection. Careful attention to implant size and soft tissue reconstruction also can optimize functional outcomes. Proper stem selection, bone preparation, cementation technique, and use of extracortical fixation can reduce the risk of aseptic loosening and maximize implant longevity. Following resection of a bone tumor, careful measurement of the specimen is necessary to select the desired implant length. Trial components, available with all modular systems, permit easy comparison with the specimen and permit multiple trial reductions to determine optimal length and positioning for the final implant. Meticulous preparation of the intramedullary canal is done for stem insertion. Selection of the stem diameter depends on the anatomy of the canal, which should be sequentially reamed so that it can accommodate the largest diameter stem possible. Tendon and soft tissue reconstruction is determined by the anatomic site and the amount of residual tissue

following tumor resection. Again, functional outcome can be enhanced with meticulous attention to details and restoration of proper biomechanics. Rotational muscle flaps often are necessary to ensure adequate soft tissue coverage and also may serve to reinforce tendon attachments or capsular tissue. Frequently performed transfers include the following:

Shoulder. Transfer of the pectoralis major and latissimus dorsi muscles covers and dynamically stabilizes a proximal humeral prosthesis. Dacron tapes are used to suspend the prosthesis statically from the scapula. Hip. Transfer of the psoas and external rotators is performed to create a pseudocapsule around the prosthetic head. This capsule then is reinforced with circumferential Dacron tapes to prevent dislocation. Reattachment of the abductor muscles is necessary to minimize the Trendelenburg lurch in the postoperative phase. This limp improves over time with strengthening of the abductors. Knee. Twenty-five percent of distal femoral replacements and all proximal tibial replacements require rotation of a gastrocnemius muscle (typically the medial head) to repair the soft tissue defect following resection of a tumor around the knee. In addition, this local flap is incorporated into P.46 the reconstruction of the patellar tendon for proximal tibial replacements.5,7

Table 1 Long-term Survival of 242 Endoprosthetic Replacements from a Single Institution Based on Kaplan-Meier Survival Analysis

No. of Patients

Failuresa

Median F/U (mo)

MRS PH

36

4

30

0.89

0.89 (0.701.00)

0.76 (0.301.00)

MRS PF

22

0

25

1.00

1.00

1.00

MRS DF

78

11

29

0.94

0.86 (0.780.94)

0.76 (0.560.94)

MRS PT

31

7

33

0.94

0.86 (0.331.00)

0.65

All MRS

173

22

30

0.93

0.86 (0.820.91)

0.76 (0.640.88)

All custom implants

50

23

85

0.71

0.81 (0.770.87)

0.55 (0.470.62)

All limbs

242

55

37

0.92

0.88 (0.850.90)

0.85 (0.810.90)

Prosthesis Type

No. of

Survival at Median F/U

5-Y Survival (95% CI)

10-Y Survival (95% CI)

aFailure was defined as implant

removal for any reason; patients were censored at time of last follow-

up or at time of death. F/U, follow-up; MRS, modular replacement system; PH, proximal humerus; PF, proximal femur; DF, distal femur; PT, proximal tibia.

Final closure of the wound may be jeopardized by skin loss following resection of a biopsy tract. In general, patients with very large tumors often have redundant skin because the tumor has acted as an internal skin stretcher. This extra skin may be rotated or trimmed as needed to facilitate wound closure. Excess skin along the incision should be excised to avoid marginal wound necrosis related to disruption of the microvasculature from elevation of large subcutaneous flaps. Patients with tight skin closures are best served by leaving the skin open to avoid pressure-induced ischemia and performing a primary or secondary split-thickness skin graft. Limbs should be elevated maximally in the postoperative phase to reduce swelling that can jeopardize the wound closure. Use of large-bore closed suction drains and correction of any postoperative coagulopathies help prevent hematoma formation. Patients who develop hematomas or wound breakdowns require aggressive treatment in the operating room to prevent secondary infection of the endoprosthesis.

FIG 12 • A. Kaplan-Meier survival curve comparing all MRS by anatomic site. Proximal femur and proximal humerus replacements have the most superior survival results, followed by distal femur, and then proximal tibia. B. Kaplan-Meier survival curve showing superior results of MRS when compared to custom prostheses over all anatomic sites.

CLINICAL RESULTS FOLLOWING ENDOPROSTHETIC REPLACEMENT Prosthetic survival has improved dramatically as improved surgical techniques, advanced prosthetic designs, and modern manufacturing techniques have been adopted. Results of early custom prostheses were disappointing, leading many surgeons to use allografts or other methods of reconstruction. More recently, there has been increased interest in endoprosthetic reconstruction as multiple centers have reported improved outcomes. Informal polling of members of the Musculoskeletal Tumor Society has shown a significant swing from a majority of members using primarily allograft reconstructions to a majority of members using endoprosthetic reconstruction. Recently published results looking at long-term survival of 242 cemented endoprosthetic replacements10 demonstrated an overall survival of 88% at 5 years and 85% at 10 years (Table 1). Prosthetic survival varied

by type and location, with the poorest survival seen in patients with early custom-designed implants and in patients with proximal tibial replacements. Infection was the single most common cause of implant failure, with infected patients having an 83% risk of implant failure (FIG 12). P.47 Functional results vary by implant location. Outcomes following reconstruction of the distal femur in 110 patients were judged as good to excellent in 85% of patients.3

COMPLICATIONS Complications following any type of limb-sparing reconstruction are not uncommon. Most patients have depressed immune systems from chronic disease, chemotherapy, and malnutrition. Patients often are anemic and have clotting abnormalities, including thrombocytopenia. The presence of long-term indwelling catheters for the administration of chemotherapy may lead to unrecognized bacteremia and potential hematogenous seeding of the operative site. The anatomic location of a tumor and necessary resection may result in significant disruption of the venous and lymphatic drainage of the extremity during resection, leading to venous stasis, swelling, and lymphedema. This can lead quickly to flap necrosis during the postoperative period, secondary infection, and eventual amputation. Finally, oncologic complications, including local recurrence of tumor or tissue necrosis from radiation, may result in failure of a limb-sparing procedure. Complications specific to endoprosthetic reconstruction may be related to mechanical or biologic factors. Prosthetic fracture, disassociation of modular components, fatigue failure, and polyethylene wear have been described. Improved implant designs, metallurgy, and manufacturing techniques can reduce the incidence of these problems significantly. Our institutional experience with more than 200 MRS (Materials Research Society, Warrendale, PA) implants over the past 18 years have revealed no stem fractures, body fractures, or taper disassociations to date. Polyethylene bushing failure occurs in fewer than 5% of patients with the Kinematic rotating hinge mechanism. Biologic failure of an endoprosthesis may occur as a result of joint instability, aseptic loosening, or periprosthetic fracture of bone around the prosthesis. Meticulous attention to soft tissue reconstruction has virtually eliminated joint instability as a problem. The use of circumferential porous coating, properly sized large-diameter stems, and third-generation cementation techniques has helped to prevent aseptic loosening in our patients. Surgical technique and the use of polished cemented stems have prevented periprosthetic fractures during surgery. Several patients with secondary, late fractures as a result of blunt trauma (eg, falls, auto accidents) have been treated successfully with casting and protected weight bearing.

FUTURE TRENDS FOR ENDOPROSTHETIC RECONSTRUCTION Current modular endoprosthetic reconstruction has greatly facilitated limb-sparing surgery following resection of bone sarcomas. Its success also has expanded the indications to include bone defects for nononcologic problems. Increasing experience in the salvage of failed total joint replacements, chronic nonunions of fractures, and reconstruction following radical resection of osteomyelitis has shown that the proven concepts of limb-sparing surgery can be applied to many different clinical situations. Today, more endoprosthetic

reconstructions are performed for nononcologic reconstructions than for osteosarcomas. Ongoing research continually strives to improve the outcome following endoprosthetic reconstruction. Continued work on improved metallurgy and polymers, particularly with the introduction of cross-linked polyethylene, promises improved long-term durability. Routine use of premixed antibiotic cement and experimentation with antimicrobial implant surfaces may help to reduce the risk of periprosthetic infection. New techniques for tendon attachment to the prosthesis include novel clamps and ingrowth surfaces to promote improved junctional strength. New implant technologies such as the Repiphysis noninvasive expandable prosthesis offer hope to younger children with few alternative options. New fixation methods, including hydroxyapatite stems with porous-coated surfaces, may be of great value in nononcologic patients. The recently introduced Compress system represents the first new method of prosthetic fixation in decades. We have already adapted this system to expand the applicability of intercalary endoprosthetic reconstruction. Although future advances in tissue engineering hold the promise of artificially engineered living bone, we expect that endoprosthetic reconstruction will remain the preferred choice of orthopedists for many years to come.

REFERENCES 1. Aboulafia AJ, Buch R, Mathews J, et al. Reconstruction using the saddle prosthesis following excision of primary and metastatic periacetabular tumors. Clin Orthop 1995;314:203-213. 2. Bickels J, Meller I, Henshaw RM, et al. Reconstruction of hip joint stability after proximal and total femur resections. Clin Orthop 2000; 375:218-230. 3. Bickels J, Wittig J, Kollender Y, et al. Distal femur resection with endoprosthetic reconstruction: a long term followup study. Clin Orthop 2002;400:225-235. 4. Capanna R, Morris HG, Campanacci D, et al. Modular uncemented prosthetic reconstruction after resection of tumours of the distal femur. J Bone Joint Surg Br 1994;76B:178-186. 5. Henshaw RM, Bickels J, Malawer MM. Modular endoprosthetic reconstruction for lower extremity skeletal defects: oncologic and reconstructive indications. Semin Arthroplasty 1999;10:180-187. 6. Kawai A, Muschler GF, Lane JM, et al. Prosthetic knee replacement after resection of a malignant tumor of the distal part of the femur. J Bone Joint Surg Am 1998;80A:636-647. 7. Malawer MM, Price WM. Gastrocnemius transposition flap in conjunction with limb-sparing surgery for primary bone sarcomas around the knee. Plast Reconstr Surg 1984;73:741. 8. Marcove RC, Lewis MM, Rosen G, et al. Total femur and total knee replacement. A preliminary report. Clin Orthop 1977;126:147-152. 9. Moore AT, Bohlman HR. Metal hip joint: a case report. J Bone Joint Surg Am 1943;25(3):688-692. 10. Rosen G, Marcove RC, Caparros B, et al. Primary osteogenic sarcoma. The rationale for preoperative

chemotherapy and delayed surgery. Cancer 1979;43:2163-2177.

Chapter 4 Expandable Prostheses Lee Jeys Adesegun Abudu Robert Grimer

BACKGROUND The two most common primary malignant bone tumors, osteosarcoma and Ewing sarcoma, are principally diseases of childhood and adolescence, with 45% of patients younger than 16 years and 17% younger than 12 years at diagnosis. In the last 30 years, the 5-year survival rate has increased from 10% to 70%. Even in patients with metastases at diagnosis, the 5-year survival rate has reached 20% to 30% due to chemotherapy and surgery for metastases as well as the primary tumor.11 Bone tumors in children occur predominantly in the metaphyseal region, close to the growth plate, so that sacrifice of a major physis often is necessary when the tumor is excised. Children who have primary bone sarcoma often require chemotherapy, which may have a subsequent suppressive effect on bone growth. Limb salvage surgery for bone tumors in the immature skeleton creates unique problems. Maintenance of limb length after resection of one or more major growth plates High functional and recreational demands of young patients, which require a durable reconstruction At the knee, a constrained endoprosthesis is required (most commonly a fixed or rotating hinge implant), making it necessary for the prosthesis stem to breach the physeal plate on the side of the joint opposite to the tumor. Reconstruction with expandable endoprostheses allows the maintenance of limb length equality, allows early weight bearing, results in predictable function, has a low risk of early complications, and is readily available. Disadvantages include the expense of the prostheses and the complications that are expected to increase with time in surviving patients.

ANATOMY About 60% to 70% of lower limb growth occurs around the knee (distal femur and proximal tibia physes), and about 80% of total growth of the humerus occurs in the proximal physis of the humerus. Terminal branches of the diaphyseal nutrient artery form tight loops near the physis, and the epiphysis is invaded by juxtaarticular vessels. During childhood, the physis becomes an avascular structure that lies between two vascular beds, one epiphyseal and the other metaphyseal. The epiphyseal vessels supply oxygen and nutrients; an intact epiphyseal vasculature is essential, therefore, to sustain the chondrocytes. The metaphyseal vessels interact with the physeal chondrocytes in the hypertrophic zone and must be intact to sustain normal ossification.10 Excessive periosteal stripping must be avoided at surgery to maintain subsequent growth.

INDICATIONS When the estimated leg length discrepancy at skeletal maturity is more than 3 cm or when the arm length discrepancy is more than 5 cm When the estimated arm length discrepancy at skeletal maturity is less than 5 cm, a prosthesis made up to 2 to 3 cm longer can be inserted. The operated upper limb initially is longer, but the opposite limb soon catches up. The main problem with a slight arm length discrepancy is cosmetic. Problems with bimanual tasks occur only when the difference is significant. Patients whose estimated leg length discrepancy is less than 3 cm can be treated with conventional “adult-type” prostheses made longer by up to 1.5 cm, and a “sliding” prosthetic component can be used across the remaining open physis. Girls older than 11 years or boys older than 13 years rarely require expandable prostheses because the estimated growth discrepancy after these ages is less than 3 cm (FIG 1).

IMAGING AND OTHER STAGING STUDIES Pediatric patients with suspected malignancy require the usual staging imaging studies (ie, plain radiograph and magnetic resonance imaging [MRI] scan of affected bone, chest computed tomography [CT] scan, and isotope bone scan). In addition, they require the following: Measured full-length radiograph of the affected and contralateral limb (FIG 2) Hand radiograph to estimate bone age based on Greulich and Pyle's atlas6 The estimated limb length discrepancy at skeletal maturity traditionally has been estimated using the charts devised by Anderson et al2 or Pritchett et al14,15 for upper and lower extremities. Recently, the validated multiplier method has been shown to be a simple and accurate predictor of discrepancy. It can be computed using chronologic, not bone, age and requires only a single measurement.1,13

SURGICAL MANAGEMENT In our center, the most common sites for the use of expandable endoprostheses are the distal femur (52%), proximal tibia (24%), proximal humerus (10%), and proximal femur (6%). Surgical techniques for excision of the sarcoma are similar to those for adult tumors, which are discussed in later chapters P.49 (see Chaps. 9, 10, and 24,25 and 26). This chapter deals primarily with factors that must be considered with the use of expandable prostheses.

FIG 1 • A,B. Charts show growth remaining for major physes. (Data from Pritchett JW, Bortel DT. Single bone straight line graphs for the lower extremity. Clin Orthop Relat Res 1997;342:132-140 and Tupman GS. A study of bone growth in normal children and its relationship to skeletal maturation. J Bone Joint Surg Br 1962;44B:42-67.) We currently use two main methods of lengthening expandable endoprostheses in our center. Their advantages and disadvantages are outlined in the following paragraphs (Table 1):

FIG 2 • Measured films of the whole femur with engineer's annotations. The minimally invasive expandable prosthesis has been in use since 1993. It is lengthened using a worm drive mechanism (FIG 3A,B). The mechanism is encased within the prosthesis shaft, and the telescopic implant is extended using an Allen key. The operative technique for lengthening is described later in this chapter. The noninvasive expandable prosthesis has been in use since 2002. Surgery is not required to lengthen the prosthesis. A sealed motor unit inside the prosthesis contains a powerful magnet that can be activated by an external power source (eg, a rotating electromagnetic field). This causes the magnet to turn, and the motor works using a very-low-ratio gearing system (13061:1) to lengthen the prosthesis. The rate of lengthening is directly proportional to the length of time that the power source is applied: Lengthening of 4.6 mm takes 20 minutes (FIG 3C-E). The physis on the opposite side of the joint can be either preserved using a sliding prosthesis or sacrificed and replaced with a fixed cemented prosthesis.

The sliding component is an uncemented, smooth component placed through a canal made centrally in the remaining preserved physis. In larger children, it is fitted inside a plastic sleeve inside the bone, which acts as a centralizer. This sleeve allows the component to slide inside the bone as the remaining open physis grows (FIG 3F,G). Care must be taken to minimize damage to the proximal growth plate by avoiding excessive periosteal stripping and carefully drilling out a cylindrical hole in the bone and, preferably, the center of the physis. Insertion of the sliding component destroys no more than 13% of the growth plate in the distal femur and proximal tibia. There is no correlation between the surface area destroyed and continued growth of the physes.3,4,7 Animal models of transphyseal pediatric anterior cruciate ligament reconstruction have shown similar results.8 P.50

Table 1 Methods of Lengthening Expandable Endoprostheses Minimally Invasive Prosthesis

JTS Noninvasive Prosthesis

Advantages

Prosthesis relatively inexpensive ($14,100) Can have subsequent MRI scans Reliable, with published longterm results for all sites (used since 1993) Available in uncemented versions Can revise easily to another expandable prosthesis without disturbing bone implant interface

No surgery required for lengthening No risk of infection No anesthesia risk Reduced scarring Painless Outpatient procedure with reduced hospital costs

Disadvantages

Requires percutaneous operation to lengthen Increased risk of infection Increased anesthesia risk Requires day case admission with increased hospital costs Scarring with slight pain after procedure

Prosthesis is expensive ($26,500). Cannot have subsequent MRI scans (will damage magnet of both prosthesis and MRI) Recent advance; therefore, no longterm results available Not available in uncemented version (forceful impaction damages motor) Currently unable to exchange lengthening module without removing whole prosthesis (development in progress)

MRI, magnetic resonance imaging.

FIG 3 • Minimally invasive prosthesis showing the port used for lengthening (A) and demonstrating the worm drive mechanism (B). C. Internal design of the shaft of the JTS noninvasive prosthesis (Stanmore Implants Worldwide, Hertfordshire, United Kingdom). D. Gearbox and magnet component of a noninvasive prosthesis. E. Patient undergoing lengthening using an electromagnetic coil. Lengthening of 4.6 mm will take 20 minutes but can be done in the outpatient department. F. Schematic illustration of a sliding component in the proximal tibia. The proximal tibial physis is preserved, and the uncemented smooth prosthesis slides within the polyethylene sleeve as the physis grows. G. Illustration of the amount of growth of the proximal tibial physis 6 years after a distal femoral replacement with a sliding tibial component. The amount of growth can be seen by the growth arrest line formed at the time of chemotherapy. Growth on the affected side is only slightly less than that on the normal side. H. The use of hydroxyapatite-coated collars has been shown to reduce the rate of aseptic loosening by encouraging bone ongrowth. P.51 Physes with “sliders” grow at a slower rate, achieving about 80% of normal growth in the proximal tibia and about 60% of normal growth in the distal femur compared with the contralateral limb4 (see FIG 3G). Other methods of lengthening prostheses are in use worldwide. A device developed by Kotz et al9 allows the prosthesis to be lengthened by a ratchet system that uses knee movement to cause it to lengthen. The Phenix system (Phenix Medical, Paris, France) is a noninvasive system that relies on a coiled spring located inside the prosthesis, contained within a shield of wax. When a power source is applied to the

prosthesis, the wax melts and the spring extends. When the power source is removed, the wax solidifies and the spring is fixed in its new position.12 The following factors are important when using expandable prostheses: Resect the tumor with a wide margin and divide the bone at the predetermined level of transection. When an expandable replacement is being used, plan to replace the exact amount of bone that has been removed. If cement is being used, the intramedullary canal must be prepared adequately. We advocate the use of antibioticimpregnated cement. The use of hydroxyapatite-coated collars and preservation of periosteal sleeve significantly reduces the long-term risk of aseptic loosening by encouraging bony ingrowth to the prosthesis and also avoids the risk of stress shielding seen in some uncemented types of implants (FIG 3H).

Preoperative Planning Calculate estimated limb length discrepancy at skeletal maturity. Allow for reduced growth from any growth plates disturbed by surgery. Consider whether any surgical options other than an expandable prosthesis are feasible. These include the following: The use of a shoe lift if the difference is less than 2 cm Inserting an adult prosthesis (with or without a sliding component) longer than the resected bone at the time of initial surgery Planned epiphysiodesis of the opposite limb Decide whether to use an invasive or noninvasive prosthesis based on factors described previously (see Table 1). Accurately measured radiographs of the bones to be resected are sent to the engineers, together with clear information about the planned level of transection of the bone (from MRI scan or, in complex cases, crosssectional imaging of the resection level). Screen and treat patients for potential infective foci: dental hygienist review; methicillin-resistant Staphylococcus aureus (MRSA) screening; inspection for common sites of infection such as central venous lines, throat, ingrown toenails, and fungal skin infections. Ensure adequate neutrophil and platelet counts prior to surgery if patient has had recent chemotherapy (our unit requires a neutrophil count >1000/mm3 and platelet count of 75,000/mm3 or higher).

Positioning Positioning is chosen according to the usual technique and approach that the surgeon is familiar with for adult prostheses. We favor double skin preparation with chlorhexidine followed by an alcohol-based solution. The limb should be draped in such a way as to be left free and mobile during the procedure. The standard positions we use for common sites of reconstruction are as follows: Distal femur: supine with removable sterile leg support

Proximal tibia: supine with removable sterile leg support Proximal humerus: “beach-chair” position with arm supported on small side table and head turned away supported on head ring Proximal femur: lateral position

Approach Resection of the tumor should be carried out by the usual technique and approach that the surgeon is familiar with for adult prostheses. We favor an anteromedial approach to tumors around the knee. We routinely open the knee joint and reflect the extensor mechanism laterally unless there is evidence of frank knee joint invasion (which is a relative contraindication to limb salvage). If the knee joint is involved, consider an extra-articular resection if sufficient soft tissue will be left to cover the prosthesis. For tumors around the hip, we favor a direct lateral approach, and for tumors of the proximal humerus, we favor the expansile approach of Henry.

TECHNIQUES Surgical technique for the implantation of expandable prostheses is described for each common anatomic site—in greater detail for the distal femur but with only the salient specific points for each of the other sites.

▪ Distal Femoral Expandable Prosthesis Tumor is excised at a predetermined level via an anteromedial incision and medial parapatellar approach, preserving a short periosteal sleeve to cover the hydroxyapatite collar to promote bony ongrowth to the prosthesis (TECH FIG 1). A bone marrow sample is sent from the resection level for histologic review. The proximal femoral canal is prepared using flexible reamers, bushes, irrigation, and cement restrictors, as appropriate. The tibial osteotomy should be done perpendicular to the long axis of the tibia so as to be parallel with the ankle joint, removing 1 cm of bone from the proximal tibia. P.52

TECH FIG 1 • A. MRI scan of distal femoral osteosarcoma. Although the tumor appears to stop short of the physis, subperiosteal extension is present below the physis. The proximal limit of tumor will be more clearly visible on T1-weighted images. B. Anteromedial approach to the distal femur, showing excision of the biopsy tract and incision of the tendon of the rectus femoris. C,D. Dissection through the knee joint, dissecting the popliteal vessels from the posterior femur. E. Resected tumor with components. F. Tibial plateau resected 10 mm below joint line and perpendicular to the ankle joint. A central hole is reamed carefully to accept a sliding component. (continued) P.53

TECH FIG 1 • (continued) G,H. A polyethylene sleeve is inserted, uncemented, into the tibial plateau, and the metallic stemmed tibial implant is trialed. I. The distal femoral component is cemented into place and the two prostheses secured with the bushes. J. The range of flexion is tested on the table. K. The resected specimen showing the extent of the tumor, with closest margin indicated by the inked circle. Following neoadjuvant chemotherapy, 98% of the tumor was necrotic. Great care must be taken to minimize damage to the proximal growth plate by avoiding excessive periosteal stripping and carefully drilling out a cylindrical hole in the bone, of sufficient size to accept the intramedullary stem, which is then inserted uncemented into the bone. In some cases, a plastic tube is placed inside the bone to allow the stem to be centralized and to encourage sliding. This sometimes causes the stem to take a different path from that previously reamed; in such cases, the stem should be retrialed. A trial reduction should be performed to check the soft tissue tension because acute overlengthening may cause neurologic impairment and fixed flexion deformities with subsequent stiffness. Once the prosthesis is cemented into place, the site of the screw mechanism can be marked on the skin by a stab incision to make subsequent percutaneous lengthening easier if a minimally invasive prosthesis is being used. The skin is closed in layers over a drain, and dressings are applied.

▪ Proximal Tibial Expandable Prosthesis The proximal tibia is a challenging site for limb salvage, with an above average incidence of complications. The tumor is excised in a manner similar to that used with adult prostheses, with thick fasciocutaneous flaps to prevent skin necrosis. The distal femur is cut to accept the prosthesis, avoiding excessive periosteal stripping. A central drill hole is made carefully to accept the sliding component and distal femoral stem.

The medial gastrocnemius muscle is mobilized on a pedicle based on the medial sural artery and is used to cover the prosthesis and sutured to the anterior muscles. The tibial implant is cemented into place, and the sliding femoral component is inserted. The medial gastrocnemius flap replaces the extensor mechanism. Some surgeons have advocated using Dacron grafts attached to the prosthesis and the patella tendon. P.54

▪ Expandable Prosthesis for the Proximal Humerus Resection of the proximal humerus leaves a weak shoulder and rotator cuff but functioning elbow and hand. If there is a well-innervated deltoid, the humeral replacement head can be placed deep to it. If the deltoid is damaged in any way, we often use Mersilene mesh (Ethicon, Inc., Somerville, NJ) to provide a false capsule extending from the edge of the glenoid around the humeral head to prevent upward subluxation. Other authors have advocated using a polyethylene terephthalate (Trevira; Sans Fibres [Proprietary] Limited Sacks Circle, Bellville, South Cape Province, South Africa, South Africa) tube to allow soft tissue attachments to prostheses.5 Attempts are made to preserve the coracoacromial ligament to reduce the risk of proximal subluxation with lengthening. Care must be taken to prevent proximal migration of the humeral head when carrying out lengthening procedures.

▪ Proximal Femoral Expandable Prosthesis Inserting an expandable prosthesis into the proximal femur is a challenge because the hip abductors must be detached from the greater trochanter. They can be reattached to the fascia lata with the leg in slight abduction, which results in reasonable abduction power. The type of femoral head to use is the subject of ongoing debate. Uni- or bipolar femoral head replacements are used most frequently. Both have high failure rates, with a significant risk of late head subluxation in children. Small-sized femoral heads have a significant risk of dislocation. Consider a large bearing total hip arthroplasty once the patient has reached skeletal maturity. We currently favor a large bearing metal-on-metal articulation for the increased wear characteristics and reduced dislocation rates.

▪ Percutaneous Lengthening for Minimally Invasive Prostheses The patient is placed in the supine position with access to the lengthening port. In older children, the lengthening can be performed under a local anesthetic, but general anesthesia is preferred in younger children. The procedure is performed under radiographic control to keep the incision as small as possible. After double skin preparation and intravenous antibiotic prophylaxis, a stab incision is made over the jack point down to the prosthesis cavity. The jack point is identified radiologically, and the Allen key engaged into the mechanism. Soft tissue occasionally may need to be cleared from the jack point with a small periosteal elevator. The screwdriver is rotated to lengthen the prosthesis: 10 revolutions of the screw driver lengthen the

prosthesis by 0.1 cm; therefore, 100 revolutions are required to lengthen by 1 cm. Intermittent single-shot images are taken to confirm lengthening. Most lengthening procedures are done 10 mm at a time. If lengthening of much more than this is attempted, it can lead to complications such as the development of a fixed flexion deformity or, occasionally, a neurapraxia (eg, a foot drop).

PEARLS AND PITFALLS Growth potential

▪ Adequately estimate expected growth potential. ▪ If family members are very tall, the use of standard growth charts may not be adequate. ▪ Do not forget that chemotherapy causes a delay of normal growth. ▪ Is it possible to use a longer adult prosthesis and slider?

Soft tissue handling for sliders

▪ Avoid excessive surgical insult to the physis and periosteum.

How much to lengthen?

▪ Usually, 10 mm will be sufficient. More may cause stiffness and neurologic compromise.

How often to lengthen?

▪ Most patients notice when leg length discrepancy reaches more than 15 mm. ▪ Children receiving chemotherapy rarely need lengthening. ▪ Children who are having a growth spurt may require lengthening every 6 weeks.

Joint subluxation

▪ Proximal humerus: Use Mersilene mesh as pseudocapsule. ▪ Proximal femur: Convert unipolar head to total joint replacement when triradiate cartilage is fused.

Pathologic fractures

▪ Increased risk of femoral fracture above sliding component with tibial prostheses ▪ Internal fixation is best treatment. ▪ If prosthesis is loose, revise to longer stem, bypassing the fracture at time of internal fixation.

Infection

▪ Dreaded complication of minimally invasive prostheses ▪ Recorded infection rate is 1% per lengthening procedure. Noninvasive procedure should reduce risk of infection. ▪ Treat acute infection with washout and 6 weeks intensive antibiotics. Chance of cure is only 20%, however. ▪ Two-stage revision is needed for chronic infection.

Fixed flexion deformities

▪ Joint stiffness can be a problem after lengthening, especially with tibial prostheses. ▪ Try to lengthen in smaller increments and more frequently than used to correct large limb discrepancies. ▪ May be due to low-grade infection

P.55

POSTOPERATIVE CARE We advocate 24 hours of intravenous broad-spectrum prophylactic antibiotics postoperatively. We advocate early removal of surgical drains (within 48 hours). Patients with distal femoral replacements Are allowed to mobilize partial weight bearing at 48 hours Are begun on both active and passive knee exercises Usually can achieve active straight-leg raise by day 5 and knee flexion to 90 degrees within 10 days prior to discharge Patients with proximal tibial replacements Are allowed to mobilize partial weight bearing at 48 hours but can wear an extension brace to protect the

extensor mechanism for 4 weeks During that time, they are allowed to flex to about 45 degrees but are not permitted to perform active knee extension. Patients with proximal femoral replacements are kept on bed rest with the leg abducted for 5 to 7 days before getting up, after which they are permitted partial weight bearing for 6 weeks. Patients with humeral replacements are kept in a sling for 6 weeks but with active exercises of the elbow, wrist, and hand. At 6 weeks, all patients start intensive physical therapy and hydrotherapy, at which time they commence full weight bearing and active exercises to maximize functional recovery.

Patient Information Warn patients that they have an artificial implant, which can fail. Caution them to avoid contact sports. Walking, swimming, cycling, and other noncontact sports are encouraged.

Any infective process in the body can lead to infection of the prosthesis, and early treatment with antibiotics is recommended. Antibiotics for prophylaxis during dental procedures is required only if infection is present. Patients with noninvasive endoprostheses cannot have an MRI scan.

OUTCOMES Over the past 30 years, our unit has operated on 615 children younger than 16 years with primary malignant bone tumors. Seventy-four patients (12%) required amputation and the remainder (408 patients) had limb salvage using a prosthesis. Of the 176 patients with an expandable prosthesis, 117 are still alive and 89 have reached skeletal maturity. Sixty patients never had a lengthening procedure carried out either because they developed recurrent disease (metastases or local recurrence) or a complication such as infection. One hundred sixteen patients had one or more lengthening procedures, with a mean of 5.3 lengthening procedures per patient (range, 0 to 17 procedures) with an average total length increase of 32 mm (range, 0 to 120 mm). Nineteen patients needed an amputation either because of local recurrence (11 cases) or infection (8 cases). The overall limb salvage using Kaplan-Meier survival curves was 83.9% at 20 years from insertion.

COMPLICATIONS Infection Deep prosthetic infection is a major concern in children who have expandable prostheses because of the need for multiple operative procedures.

The cumulative risk of infection in our series was 21% at 10 years. It was related to site (proximal tibia) and previous highly invasive prosthesis designs. The use of gastrocnemius flaps and minimally invasive implants has reduced the infection rate to 8% at 10 years. The risk of infection has decreased from 3% per lengthening to about 1% with minimally invasive prostheses. Noninvasive prostheses should decrease the risk of infection over time.

Loosening The use of hydroxyapatite collars has significantly reduced the incidence of aseptic loosening. Revision usually is fairly straightforward, and the prosthesis is changed to an adult model (FIG 4A,B). Always consider the possibility that the loosening may be caused by low-grade infection.

Unplanned Shortening or Lengthening An unusual complication due to mechanism failures, which usually requires revision of the implant (FIG 4C).

Stiffness Stiffness is a common problem in younger children with prostheses around the knee, or if the prosthesis inserted is longer than the resected bone to try to gain some extra length. P.56 In some children, excessive scar tissue builds up around the prosthesis; in such cases, removal of the scar tissue can be helpful, combined with intensive physical therapy. In cases of fixed flexion deformities, intensive physical therapy, including the use of serial plaster casting, may be useful.

FIG 4 • A,B. Aseptic and rotational loosening in the distal femur after 14 years. C. Acute shortening due to displacement of a lengthening ring medially, which required revision to an adult prosthesis. D. Hip subluxation has been a problem in young patients receiving proximal femoral replacements.

Subluxation of Hip or Shoulder

Subluxation at the shoulder can be reduced by the use of Mersilene mesh. Femoral head subluxation is far more of a problem in younger children with proximal femoral replacements. We have found that in children younger than 12 years, there is an increasing tendency for the superior margin of the acetabulum not to develop properly, and in these children, the femoral head will sublux. We have tried several techniques to prevent subluxation, without success, and now revise the unipolar head to a large bearing surface uncemented cup when the triradiate cartilage is fused or subluxation is apparent (FIG 4D).

Outgrowing the Available Extension The maximum lengthening available in a prosthesis is 120 mm, but in many cases, less than that is needed. Revision usually involves replacing only one component of the prosthesis.

Implant Breakage Implant breakage is rare in patients who have reached maturity with a child's prosthesis still in place. The most common site for a fracture is at the junction of the thinner lengthening portion with the main component. Revision is required in all cases.

Periprosthetic Fractures Periprosthetic fractures are rare, but there seems to be an increased risk of femoral fractures above a sliding femoral prosthesis used in conjunction with a proximal tibial growing prosthesis.

REFERENCES 1. Aguilar JA, Paley D, Paley J, et al. Clinical validation of the multiplier method for predicting limb length at maturity. Part I. J Pediatr Orthop 2005;25:186-191. 2. Anderson M, Green WT, Messner MB. Growth and predictions of growth in the lower extremities. Clin Orthop Relat Res 1978;136:7-21. 3. Cool WP, Carter SR, Grimer RJ, et al. Growth after extendible endoprosthetic replacement in the distal femur. J Bone Joint Surg Br 1997;79B:938-942. 4. Cool WP, Grimer RJ, Carter SR, et al. Passive growth at the sliding component following endoprosthetic replacement in skeletally immature children with primary bone tumour around the knee. J Bone Joint Surg Br 1996;78B(suppl 1):33. 5. Gosheger G, Hillmann A, Lindner N, et al. Soft tissue reconstruction of megaprostheses using a Trevira tube. Clin Orthop Relat Res 2001;393:264-271. 6. Greulich WW, Pyle SI. Radiographic Atlas of Skeletal Development of the Hand and Wrist, ed 2. Stanford, CA: Stanford University Press, 1959. 7. Grimer RJ, Belthur M, Carter SR, et al. Extendible replacements of the proximal tibia for bone tumours. J Bone Joint Surg Br 2000;82B: 255-260. 8. Guzzanti V, Falciglia F, Gigante A, et al. The effect of intra-articular ACL reconstruction on the growth

plates of rabbits. J Bone Joint Surg Br 1994;76B:960-963. P.57 9. Kotz RL, Windhager R, Dominkus M. A self-extending paediatric leg implant. Nature 2000;406:143-144. 10. Laor T, Jaramillo D, Oestreich AE. Musculoskeletal system. In: Kirks DR, ed. Practical Pediatric Imaging. Diagnostic Radiology of Infants and Children, ed 3. Philadelphia: Lippincott-Raven, 1998:327-510. 11. Longhi A, Errani C, De Paolis M, et al. Primary bone osteosarcoma in the pediatric age: state of the art. Cancer Treat Rev 2006;32:423-436. 12. Neel MD, Wilkins RM, Rao BN, et al. Early multicenter experience with a noninvasive expandable prosthesis. Clin Orthop Relat Res 2003;415:72-81. 13. Paley D, Bhave A, Herzenberg JE, et al. Multiplier method for predicting limb-length discrepancy. J Bone Joint Surg Am 2000;82A: 1432-1446. 14. Pritchett JW. Growth plate activity in the upper extremity. Clin Orthop Relat Res 1991;268:235-242. 15. Pritchett JW, Bortel DT. Single bone straight line graphs for the lower extremity. Clin Orthop Relat Res 1997;342:132-140. 16. Tupman GS. A study of bone growth in normal children and its relationship to skeletal maturation. J Bone Joint Surg Br 1962;44B: 42-67.

Chapter 5 Surgical Management of Metastatic Bone Disease: General Considerations Jacob Bickels Martin M. Malawer

BACKGROUND The skeleton, after the lungs and liver, is the third most common site of metastatic disease.4,11 Prostate, breast, lung, kidney, and thyroid cancers account for 80% of skeletal metastases.4,11 The prolonged survival with disease of more cancer patients has led to continuously growing numbers of patients with metastatic bone disease (MBD). The exact incidence of bone metastases is unknown, but it is estimated that in the United States alone, 350,000 people die with bone metastases from primary carcinomas.13 MBD is a major factor contributing to deterioration of the quality of life in patients with cancer. These patients may require surgical intervention for the management of impending or present pathologic fracture or for the alleviation of intractable pain associated with a locally progressive lesion. Those skeletal crises are associated with a considerable loss of function, pain, and the associated impairment of quality of life. Surgery may also be performed to remove a solitary bone metastasis with the intent of improving long-term survival in selected patients,1,9 but other than this rare exception, these surgical interventions are mainly palliative and aimed at achieving local tumor control, structural stability of the surgically treated site, and restoration of normal function as quickly as possible. Failure to achieve one of these goals usually necessitates a second surgical intervention, and this is associated with additional impairment of an already compromised quality of life. Reports show failure rates of surgeries done for MBD as high as 40% and occurring as the result of a poor initial fixation, improper implant selection, and progression of disease in the operative field.3,8,14,15 An attempt to treat a pathologic fracture as one would treat a traumatic fracture will fail in most cases because the underlying disease impedes the fracture healing process. The prognosis for union of a pathologic fracture is also determined to some extent by the tumor type: Those associated with metastatic adenocarcinomas of breast and prostate, multiple myeloma, and lymphoma successfully unite far more frequently than do those associated with malignancies of the lung, kidney, and gastrointestinal tract.5,6,7 Even when healing does occur, it does so after an unreasonably long period of time and is of a less than satisfactory quality. Reduction and immobilization used in the management of traumatic fractures are, therefore, not applicable in the management of pathologic fractures due to MBD. Gainor and Buchert5 analyzed 129 pathologic fractures and found that the long bone fractures that healed most predictably were those which had been internally fixed and irradiated and were in patients who survived for more than 6 months postoperatively. Similar observations were made by Harrington et al.7 Cemented hardware or prostheses are preferentially used for fixation to achieve immediate stability, and reconstruction techniques that rely on a biologic process of bone healing (such as autologous bone grafts, allografts, or allografts prosthetic composites) are inappropriate for the surgical management of MBD.2,6,7,10

INDICATIONS

Existing pathologic fracture Impending pathologic fracture Intractable pain associated with locally progressive disease that had shown inadequate response to narcotics and preoperative radiation therapy Solitary bone metastasis in selected tumor types It is agreed that surgical intervention for MBD is appropriate for patients who are expected to survive longer than 3 months. Patients who are expected to survive less than 3 months are less likely to benefit from an operation because they usually do not have the physical strength required for rehabilitation or the time needed for its completion. Those patients are treated with nonoperative approaches, such as sling and arm brace for the upper extremities or protected weight bearing for the lower extremities.

PREOPERATIVE EVALUATION Although planned surgery for patients with MBD should not be delayed, preoperative evaluation and staging must not be compromised but rather thoroughly mapped out. This evaluation allows the understanding of the morphology of the lesion and its relation to adjacent structures, determining the overall skeletal staging of the patient, and detecting any other metastases that may require simultaneous surgery. Because most patients who present with skeletal metastases have an established diagnosis of cancer, clinical and radiologic evaluations are usually aimed at evaluating the extent of the disease and the presence of its complications rather than at identifying its site of origin.

Patient History and Physical Findings Medical history should include current oncologic status and related treatments and medications. It is crucial to question the patient and/or family members about his or her overall functional status and, specifically, about the status of the P.59 affected extremity prior to the occurrence of the metastatic lesion. For example, a surgeon would be justifiably reluctant to perform major surgery on a lower extremity in a patient who was bedridden or wheelchair-bound, given that stabilization of the extremity for greater ease in maintaining pain-free personal hygiene in that patient would require a less extensive procedure. The orthopaedic surgeon should also inform the responsible medical oncologist of the impending operation, verify the oncologic information given to him or her, and be provided with the patient's estimated life expectancy. The physical examination should include evaluation of the principal symptomatic area as well as other symptomatic sites. Examination should focus on the extent of soft tissue tumor extension and its relation to the neurovascular bundle of the extremity, muscle strength and range of motion of the adjacent joints, neurovascular status of the affected extremity, and limb edema.

Laboratory Studies A complete blood count and blood chemistries should be ordered. Of specific concern in those studies is the calcium level because hypercalcemia may be a life-threatening complication of MBD. Acquiring an ionized calcium level is helpful in the diagnosis of hypercalcemia because low albumin levels may lower total calcium levels. Hypercalcemia should be treated prior to any surgical intervention. Levels of specific tumor markers should be evaluated if applicable to the specific tumor type.

Imaging Studies Plain radiographs and computed tomography (CT) of the affected site should be done as well as plain radiographs of any additional site in which the patient reports of a joint or bone pain. The combined results of these studies will define the extent of bone destruction and soft tissue extension (FIG 1). If the investigated metastasis is located in a long bone, plain radiographs of reasonable quality of its entire extent should also be done to exclude additional metastases because these data are crucial for surgical planning: Missed metastases could cause pathologic fractures upon weight bearing postoperatively and require an extensive surgery for their repair (FIG 2).

FIG 1 • A. Plain radiograph showing a metastatic tumor of the right acetabulum in a 72-year-old male with a known history of thyroid carcinoma. B. CT scan shows an extensive bone destruction and soft tissue extension. Attempt at resection based on the radiographic findings alone would probably result in intralesional debulking and potential exsanguination due to the extensive vascularity of this tumor. Given these radiologic findings, this patient underwent preoperative angiographic embolization that diminished blood loss in surgery and allowed successful resection. A total body bone scintigraphic evaluation using technetium 99m methylene diphosphonate (99mTc MDP) should be done prior to any surgical intervention: It provides information for entire skeletal staging for additional metastases as well as the means to detect metastases that may require simultaneous surgery. Bone scanning is highly sensitive for bone pathology. Tracer uptake, however, is not specific for MBD and may spuriously display a large variety of inflammatory, infectious, posttraumatic, and other benign conditions. Therefore, plain radiography of any positive site on bone scan should also be done. It should be borne in mind that bone scanning is not a substitute for plain radiographs of the entire affected bone or other sites with bone pain because some tumors (such as multiple

myeloma, metastatic melanoma, and thyroid carcinoma) may not show up on a bone scan (FIG 3). Chest radiographs should also be routinely done as a screening study to rule out lung metastases, considering that the lungs may be involved in the majority of common cancers. Table 1 summarizes the list of recommended studies for patients with bone metastases whose primary site of disease is unknown.

Impending Pathologic Fractures Patients with MBD who have a pathologic fracture experience a sudden onset of debilitating pain and loss of function. They require urgent hospitalization, and this may interrupt the course of an ongoing oncologic treatment. Surgery for these fractures is frequently complicated by the presence of a substantial hematoma, soft tissue edema, and difficulties P.60 P.61 in obtaining appropriate reduction and alignment because of extensive bone destruction. For these reasons, it is important to identify those metastatic bone lesions that are likely to cause a pathologic fracture (ie, “impending” pathologic fractures) and to stabilize them prophylactically.

FIG 2 • A. Plain radiograph showing a pathologic hip fracture in a 69-year-old female with a known history of breast cancer. Hip hemiarthroplasty was performed within 24 hours of fracture occurrence (B), but postoperative radiographs showed an additional metastasis just below the tip of the prosthetic stem (C) that was missed because of the poor quality of the preoperative radiographs and because whole bone radiographs were not done before surgery. D. While she was still in hospital, she suffered a pathologic fracture through that lesion as she was being shifted from her bed to a reclining chair.

FIG 3 • A. Plain radiograph showing a pathologic fracture of the proximal femur in a 59-year-old female with multiple myeloma. B. Bone scintigraphy revealed no additional bone lesion, and she was treated with open reduction (without tumor removal) and uncemented internal fixation. She reported unrelenting ipsilateral knee pain and was clinically diagnosed as having degenerative joint disease and associated pain. (continued)

FIG 3 • (continued) C,D. Two weeks after the reduction surgery, she reported an acute onset of severe knee pain and swelling upon weight bearing: A pathologic fracture of the distal femur was demonstrated on plain radiographs. E. This patient underwent total femur resection with endoprosthetic reconstruction. Although there is a consensus that impending fractures require prophylactic fixation, there are numerous reports describing varying concepts and methods of evaluation of these lesions as well as criteria for defining them. The agreed to and most commonly used criteria include a lytic bone lesion that measures 2.5 cm, causes circumferential destruction of 50% or more of the adjacent cortical bone, and is associated with increasing pain on weight bearing which has not responded to treatment with radiation therapy.

Table 1 Studies Required for the Preliminary Evaluation of a Patient with a Metastatic Disease with an Undetermined Primary Site of Disease Physical examination

Focus on evaluation of skin, lymphadenopathy, breast, thyroid, prostate, rectal examination

Laboratory studies

Complete blood count, blood chemistries, liver function tests, erythrocyte sedimentation rate, serum and urine protein electrophoresis, prostate-specific antigen, urinalysis, and stool guaiac study

Imaging studies

CT of chest, abdomen, and pelvis

Because of the complex anatomy of the acetabulum, a simple definition of impending or pathologic fracture is neither possible nor useful for planning surgical reconstruction at those sites. Instead, the location and extent of cortical destruction are used to evaluate the biomechanical impact on function (FIGS 4,5 and 6).6,7,12

Biopsy The mere presence of a bone lesion with a presumed diagnosis of metastasis does not mandate a biopsy. Such a lesion in a patient with an established history of malignancy and with radiologic evidence of other bone metastases does not require a biopsy prior to surgical intervention. A solitary bone metastasis in a patient with a known history of malignancy or a lesion with atypical radiologic or clinical manifestations, even in the presence of other bone metastases, must be biopsied prior to any intervention. P.62

FIG 4 • A bone lesion measuring greater than 2.5 cm, occupying more than 50% of the cortical diameter, and associated with pain on weight bearing is considered as being an impending pathologic fracture.

FIG 5 • Metastatic breast carcinoma of the proximal femur in a 59-year-old patient. The lesion was asymptomatic and had been noted on a follow-up bone scan that showed increased uptake at that site. The lesion was greater than 2.5 cm, but because it had a sclerotic rim, occupied less than 50% of the cortical diameter at that region, and did not reach the cortices to violate their integrity, it did not require surgical intervention and the patient was successfully treated with radiation therapy and bisphosphonates.

FIG 6 • Plain radiograph (A) showing a large metastasis occupying the entire proximal femoral metaphysis (B) and metastatic lung carcinoma of the femoral diaphysis in a 70-year-old male, both symptomatic upon weight bearing and both evidencing a large lytic lesion occupying more than 50% of the cortical diameter with cortical destruction ranging from endosteal scalloping to frank breakthrough. Both lesions required prophylactic surgical intervention. C. CT scan showing an impending fracture of the left acetabulum. The femoral head is facing a large lytic lesion, occupying the entire acetabular cavity. The mechanical support to the joint is provided only by the thin layer of the remaining articular cartilage. P.63

FIG 7 • A. Plain radiograph showing metastatic renal cell carcinoma of the distal femoral diaphysis. This patient was treated with closed (ie, without tumor exposure and removal) retrograde intramedullary nailing and referred to postoperative radiation therapy. B,C. Radiographs taken 3 months after surgery show considerable local tumor progression that required additional and extensive surgical intervention.

PRINCIPLES OF SURGERY The primary goals of surgery for MBD are to achieve local tumor control and structural stability of the surgically treated site. Surgery has no effect on the overall progression of disease or on patient survival. Most failures of these surgeries are attributed to inadequate tumor removal and improper reconstruction. It should be emphasized that radiation therapy is most effective when applied to microscopic disease and that it is considerably less effective when applied to large tumor volume. Surgeries done for impending or present pathologic fractures should, therefore, follow identical steps: first, removal of the tumor, and only then, reconstruction (FIG 7). The decision to perform intralesional tumor removal or proceed with a resection of the affected bone segment depends on the local extent of bone loss and proximity to the adjacent joint (FIGS 8,9,10 and 11). Because bone metastases usually have less soft tissue extension than primary sarcomas of bone, resection of bone metastases usually does not require en bloc removal of the surrounding soft tissues (FIG 12). Reconstruction must provide immediate stability that must not rely on biologic healing processes. Therefore, the use of autologous bone grafts, allografts, or allograft prosthetic composites is inappropriate in surgery for MBD. Similarly, cementless prosthetic implants have no place in this setting. Reconstruction should include the combined use of hardware/prosthetic implants and bone cement (polymethylmethacrylate [PMMA]). The latter is used to reinforce the hardware by increasing the diameter of the construct through which the mechanical load is transmitted and improving its attachment to the neighboring bone, thereby allowing the construct to withstand the mechanical stresses of immediate weight bearing and function. Stiffness and P.64 P.65 strength are related to the diameter of the intramedullary construct: The amount of stiffness in the act of bending is proportional to the diameter raised to the fourth power, and the strength in bending varies with the third power of the diameter (FIGS 13,14 and 15).

FIG 8 • A metastatic lesion of the proximal femur. Lesions such as this that do not extend to the head may be treated with intralesional tumor removal and reconstruction with cemented intramedullary nailing. On the other hand, lesions that cause extensive destruction of the femoral head may require proximal femur resection and reconstruction with cemented prosthetic implant.

FIG 9 • A. A metastatic lesion of the femoral diaphysis. Lesions such as this that have enough residual cortex to allow continuity may be treated with intralesional tumor removal and reconstruction with cemented intramedullary nailing. B. On the other hand, lesions that have caused extensive destruction and violated that continuity require intercalary resection of the femoral diaphysis.

FIG 10 • Plain radiographs (A,B) and CT scan (C) showing multiple myeloma involving the distal femur with extensive bone destruction. D. Most of the cortical diameter was destroyed and even the remaining posterior cortex had been infiltrated and thinned by the disease, and so distal femur resection with endoprosthetic reconstruction was carried out. E. The surgical specimen.

FIG 11 • Extensive and destructive metastasis of proximal femur which leaves no option but resection of the proximal femur and reconstruction with prosthesis.

REHABILITATION Full weight bearing and passive and active range-of-motion exercises of the adjacent joints should be practiced as soon as possible upon wound healing and patient ability.

ADJUVANT RADIATION THERAPY Postoperative external beam radiation therapy of 3000 to 3500 Gy is routinely administered to the entire surgical field to control remaining microscopic disease. That dose of radiation does not impede callus formation if it is feasible, as determined by underlying fracture characteristics and the patient's overall status.5,6,7 Radiation treatment is given to the patients upon healing of the surgical wound, usually 3 to 4 weeks after surgery.

FIG 12 • A. Primary bone sarcomas usually have considerable extension into the soft tissues. Resection of such tumor at the proximal humerus would require en bloc removal of the overlying deltoid muscle, rotator cuff tendons, and the joint capsule. B. Bone metastases, however, usually present with less soft tissue involvement, and their resection involves removal of bony elements with only a thin layer of surrounding soft tissues. P.66

FIG 13 • A metastatic bone lesion treated by a closed nailing. A. This procedure is simple to perform, but it may fail because tumor progression leaves the nail as the only load-transmitting component of the lower extremity, and this ultimately results in hardware failure and breakage. B. Plain radiograph showing an impending fracture of the femoral diaphysis due to multiple myeloma. Tumor removal, cemented nailing, and postoperative radiation would most likely have resulted in local tumor control and durable reconstruction. C. Closed nailing was done in

this patient, however, and tumor progression (despite radiation) resulted in unavoidable hardware breakage. D. Similar outcome of uncemented fixation of metastatic renal cell carcinoma of the subtrochanteric region.

FIG 14 • Subtrochanteric fracture following intercalary resection of a diaphyseal femoral metastasis. The use of a thin intramedullary nail, minimal cuff of cement, and supporting side plate were unable to withstand the axial forces of mechanical load. It is likely that the combination of a thick intramedullary nail and thicker cuff of cement would have prevented this fracture. P.67

FIG 15 • A. Surgery should include meticulous tumor removal and filling of the entire tumor cavity with bone cement. Plain radiograph showing renal cell carcinoma (RCC) metastasis to the proximal femur treated with only partial removal and cemented intramedullary fixation (B). RCCs are commonly unresponsive to radiation therapy, and the remaining tumor in this patient progressed and resulted in hardware failure at the hardware-cement interface.

PEARLS AND PITFALLS History and physical examination

▪ Obtain data regarding pre-MBD functional status. ▪ Consult the patient's medical oncologist for current oncologic status and estimated survival.

Laboratory studies

▪ General assessment, rule out hypercalcemia

Imaging studies

▪ Plain radiographs of the entire affected bone ▪ Total body bone scan prior to surgical intervention ▪ Evidence of painful lytic long bone metastasis >2.5 cm diameter, occupying >50% of the cortical diameter defines an impending fracture that requires prophylactic surgical intervention.

Surgical technique

▪ Tumor resection is done first. ▪ Reconstruction should include cemented internal fixation; biologic reconstruction is inappropriate.

Postoperative treatment

▪ Immediate weight bearing and range-of-motion exercises ▪ External beam radiation therapy

REFERENCES 1. Althausen P, Althausen A, Jennings LC, et al. Prognostic factors and surgical treatment of osseous metastases secondary to renal cell carcinoma. Cancer 1997;80(6):1103-1109. 2. Bickels J, Kollender Y, Wittig JC, et al. Function after resection of humeral metastases. Analysis of 59

consecutive patients. Clin Orthop Relat Res 2005;437:201-208. 3. Dijstra S, Wiggers T, van Geel BN, et al. Impending and actual pathological fractures in patients with bone metastases of the long bones. A retrospective study of 233 surgically treated fractures. Eur J Surg 1994;160(10):535-542. 4. Dorfman HD. Metastatic tumors in bone. In: Dorfman HD, Czerniak B, eds. Bone Tumors. St. Louis: Mosby, 1998:1009-1040. 5. Gainor BJ, Buchert P. Fracture healing in metastatic bone disease. Clin Orthop Relat Res 1983;178:297302. 6. Harrington KD. Impending pathologic fractures from metastatic malignancy: evaluation and management. Instr Course Lect 1986;35:357-381. 7. Harrington KD, Sim FH, Enis JE, et al. Methylmethacrylate as an adjunct in internal fixation of pathological fractures. J Bone Joint Surg 1976;58(A):1047-1055. 8. Healey JH, Brown HK. Complications of bone metastases: surgical management. Cancer 2000;88(suppl 12):2940-2951. 9. Koizumi M, Yoshimoto M, Kasumi F, et al. Comparison between solitary and multiple skeletal metastatic lesions of breast cancer patients. Ann Oncol 2003;14(8):1234-1240. 10. Kollender Y, Bickels J, Price WM, et al. Metastatic renal cell carcinoma of bone. Indications and techniques of surgical intervention. J Urol 2000;164:1505-1508. 11. Manoso MW, Healey JH. Metastatic cancer to the bone. In: DeVita VT, Hellman S, Rosenberg SA, eds. Cancer: Principles and Practice of Oncology, ed 7. Philadelphia: Lippincott Williams & Wilkins, 2005:23682380. 12. Mirels H. Metastatic disease in long bones: a proposed scoring system for diagnosing impending pathologic fractures. Clin Orthop Relat Res 1989;249:256-264. 13. Roodman DG. Mechanisms of bone metastasis. N Engl J Med 2004;350:1655-1664. 14. Wedin R, Bauer HC. Surgical treatment of skeletal metastatic lesions of the proximal femur: endoprosthesis or reconstruction nail? J Bone Joint Surg Br 2005;87(12):1653-1657. 15. Yawaza Y, Frassica FJ, Chao EY, et al. Metastatic bone disease. A study of the surgical treatment of 166 pathological humeral and femoral fractures. Clin Orthop Relat Res 1990;251:213-219.

Chapter 6 Cryosurgical Ablation of Bone Tumors Jacob Bickels Yair Gortzak Yehuda Kollender Martin M. Malawer

BACKGROUND Cryoablation is the therapeutic application of cold in situ to induce tissue necrosis with curative intent. Cryoablation of bone tumors by direct pour of liquid nitrogen is an effective adjuvant to curettage in the management of a large variety of bone tumors including benign aggressive, metastatic, and primary malignant lesions. It is an intralesional procedure, which enables the avoidance of major resection and associated loss of function. It is a very powerful technique that weakens the bone surrounding the tumor cavity and may, when not used judiciously, cause additional soft tissue injuries. Awareness of these potential complications has led to refinement of surgical practices to include soft tissue protection, stable reconstruction, and the use of perioperative antibiotics and enhancement of rehabilitation protocols for gradual weight bearing. Those guidelines resulted in a gratifying low rate of complications and rendered this treatment a safe and reliable modality. It may be expected that cryoablation will no longer be the exclusive practice of a relatively small group of surgeons and that it will eventually enjoy greater popularity in the not too distant future.

Historical Aspects and Physiologic Background Although it had been used in the 1850s for the management of locally advanced carcinoma of the cervix, the applicability of cryoablation in the management of bone tumors was not assessed until more than a century later, in the classic 1966 animal study by Gage et al13 in which the femora of living mongrel dogs were frozen by perfusing liquid nitrogen through encircling latex coils. Liquid nitrogen, which has a boiling temperature of 196 °C, allowed rapid freezing of a 2-cm rim of bone around these coils. Using histopathologic studies and plain radiographs, the authors documented the occurrence of tissue necrosis and bone resorption that was associated with mechanical weakening and spontaneous fractures.13 These changes, however, were followed by new bone formation that developed slowly, starting from the vital bone at the periphery: It was first observed at 2 months and reached its peak at 6 months after freezing.13 Although only normal bone was investigated in their experiment, Gage et al13 speculated that cold allows for nonspecific cell destruction and may induce tumor kill as well. They further suggested the use of intralesional cryoablation in lieu of tumor resection or amputation. The use of this technique in the management of human bone tumors was first reported in 1969.33 Following curettage of a metastatic bone lesion, those authors poured liquid nitrogen into the tumor cavity with the intent of inducing tumor necrosis and avoiding the need for extensive resection and reported having achieved both goals. Further studies confirmed and refined the initial findings of Gage et al13 and showed that temperatures between -21 °C and -60 °C are needed to obtain cell necrosis, whereas temperatures below -60 °C exerted no

further lethality.18,28,33 It also emerged that a number of mechanisms are responsible for the tissue necrosis induced by cryoablation.12,15,22,26,28,41,42 These mechanisms can be grouped into two categories: immediate and delayed. Four mechanisms are involved in the immediate cytotoxicity produced by cryoablation: (1) formation of ice crystals and membrane disruption, (2) thermal shock, (3) dehydration and toxic effects of electrolyte changes, and (4) denaturation of cellular proteins. The formation of intracellular ice crystals is considered as being the main mechanism of immediate cellular necrosis. The two mechanisms most likely responsible for the delayed, progressive necrosis that is observed following cryoablation and for the problems associated with subsequent repair of frozen tissue are the damage to the microvascular circulation and vascular stasis.12,28 During cryoablation, ice crystals first occur in the extracellular spaces. The withdrawal of water from the system into these crystals creates a hyperosmotic extracellular environment, which, in turn, draws water from the cells. As the process continues, these crystals grow, the cells shrink and dehydrate, electrolyte concentration is increased, and membranes and cell constituents are damaged.12,17,41 Rapid freezing, such as that achieved by direct pour of liquid nitrogen, does not allow sufficient time for the withdrawal of water from the cells and so intracellular ice crystals are formed simultaneously. Conversely, a slow thaw will cause intracellular recrystallization of the already formed crystals and membrane disruption, whereas a rapid thaw will not.2,7,41,48 Repeated freeze-thaw cycles will also increase the extent of tissue necrosis because of the improved cold conductivity following the first cycle.11,12,15 Therefore, repeated cycles of rapid freezing and spontaneous thaw will achieve the maximal effect of cell necrosis. Histologically, the most dramatic effect of cryoablation is on the appearance of the bone marrow: a rim of 1 to 2 cm of extensive necrosis with minimal inflammatory response appears, following direct pour of liquid nitrogen.13,29,39,41 This is followed by liquefaction and progressive fibrosis. Large, thickened, and thrombosed vessels are occasionally seen as well. P.69

INDICATIONS Histologic Diagnoses Benign aggressive bone tumors Giant cell tumor Aneurysmal bone cyst Simple bone cyst Fibrous dysplasia Enchondroma Chondroblastoma Eosinophilic granuloma Osteoblastoma Chondromyxoid fibroma Low-grade sarcomas of bone

Low-grade chondrosarcoma Metastatic tumors

Morphologic Criteria Cryoablation is appropriate for periarticular and sacral lesions in which the circumferential rim of the cortex that remained after tumor removal could hold liquid material and was sufficient for ensuring a mechanically stable reconstruction.

SURGICAL MANAGEMENT There are five stages in carrying out cryosurgical ablation5,6,27: Tumor exposure Thorough curettage High-speed burr drilling of the tumor cavity Cryoablation Mechanical reconstruction Cryoablation using direct pour of liquid nitrogen has several technical drawbacks. First, after it has been poured, there is no control of the overall freezing time or of the temperature at different sites within the tumor cavity. Second, it is a gravity-dependent procedure, that is, the poured liquid cannot reach corners of the tumor cavity that are positioned above the fluid level. To solve these problems, closed cryoablation using argon gas was developed and became available in the late 1990s.4 Both techniques are considered in the following text.

TECHNIQUES ▪ Direct Pour of Liquid Nitrogen Exposure When technically possible, a pneumatic tourniquet is used during the procedure to decrease local bleeding and prevent blood from acting as a heat sink and posing as a thermal barrier to cryoablation. A large cortical window the size of the longest longitudinal dimension of the tumor is made after exposure of the involved bone. It has to be elliptical with its axis parallel to the long axis of bone to reduce the stress rising effect (TECH FIG 1). Curettage and Burr Drilling All gross tumor material is removed with hand curettes (TECH FIG 2A,B). This is followed by high-speed burr drilling of all remaining macroscopic disease and the walls of the tumor cavity (TECH FIG 2C,D). Bony perforations are identified and sealed with Gelfoam (Upjohn, Kalamazoo, MI) before introduction of the liquid nitrogen. Neurovascular bundle and fasciocutaneous flaps are protected by mobilization and by

shielding (with surgical pads) from direct contact with the liquid nitrogen, after which cryoablation is performed.

TECH FIG 1 • Plain radiograph (A) and magnetic resonance imaging (MRI) showing (B) giant cell tumor of the proximal tibia. (continued) P.70

TECH FIG 1 • (continued) C. A large incision is planned to allow wide exposure of the tumor cavity. D. Fasciocutaneous flaps are mobilized and the cortical bone overlying the tumor cavity is exposed.

TECH FIG 2 • A. A large cortical window the size of the longest longitudinal dimension of the tumor is made and the tumor is first removed with hand curettes. B. Illustration showing tumor curettage. This should be meticulously performed, leaving only residual microscopic disease in the tumor cavity. C. Curettage is followed by high-speed burr drilling. D. Illustration showing high-speed burr drilling of a tumor cavity. P.71 Cryoablation The traditional technique of cryoablation entails direct pour of liquid nitrogen through a stainless steel funnel into the tumor cavity, taking care to fill the entire cavity (TECH FIG 3A,B). Thermocouples are used to monitor the freeze within the cavity, cavity wall, adjacent soft tissues, and an area 1 to 2 mm from the periphery of the cavity. The surrounding soft tissues are continuously irrigated with warm saline solution to decrease the possibility of thermal injury. Freezing (boiling of liquid nitrogen) lasts 1 to 2 minutes and is proportional to the volume of poured liquid nitrogen. It is followed by spontaneous thaw that occurs over 3 to 5 minutes. The cycle is considered complete once the temperature of the cavity rises more than 0°C. The cavity is irrigated with saline after two freeze-thaw cycles have been carried out (TECH FIG 3C-E). At this point, the process of reconstructing the tumor cavity begins.

TECH FIG 3 • The traditional technique of cryoablation using direct pour of liquid nitrogen. A. Stainless steel can and funnels. B. The surrounding soft tissues are protected with surgical pads. C. Direct pour of liquid nitrogen into the tumor cavity, which is continuously irrigated with warm saline throughout the freezing and thawing processes (˜5 minutes altogether). D. Illustration showing direct pour of liquid nitrogen and protection of the surrounding soft tissues. E. Intraoperative photograph following curettage, high-speed burr, and cryosurgery. Reconstruction Reconstruction includes the use of internal fixation and the use of polymethylmethacrylate (PMMA). Subchondral surfaces are reinforced with autologous bone graft before cementation (TECH FIG 4). P.72

TECH FIG 4 • Reconstruction includes cemented hardware and reinforcement of subchondral surfaces with autologous bone graft. This principle of reconstruction is applied in all anatomic locations: Intraoperative photos (A) and (B) showing intramedullary rods and then rods with cementation, and postoperative radiographs of fixation for (C) proximal femur, (D) distal femur, (E) proximal tibia, (F) distal tibia, (G) proximal ulna, and (H) distal radius. P.73

▪ Closed Cryoablation with Argon Gas This approach entails filling the tumor cavity with a gel medium, inserting metal probes into the gel (TECH FIG 5), and executing computer-controlled delivery of argon gas through the metal probes. Argon gas serves as the freezing agent and the surrounding gel acts as a conducting medium, which distributes the low temperature equally throughout the tumor cavity (TECH FIGS 6 and 7).

TECH FIG 5 • A. Different sizes of metal probes used for delivery of argon gas. B. Illustration showing the tumor cavity filled with gel medium and the metal probe within it. C. The gel freezes and creates an ice ball within a few seconds after perfusion of the argon gas through the probe.

TECH FIG 6 • A. Plain radiograph showing giant cell tumor of the proximal tibia. B. Curved incision along the lateral tibial metaphysis. C. Curettage. D. High-speed burr drilling. E. An ice ball is formed around the tip of the probes upon perfusion of argon gas.

Computer-controlled delivery of argon gas allows determination of the desired temperature throughout the tumor cavity as well as of the overall freezing time, and the use of a viscous gel enables filling of any shape of tumor cavity, regardless of gravity considerations (TECH FIG 8). P.74

TECH FIG 7 • A. Photograph showing recurrent low-grade chondrosarcoma of the distal radius. B. Tumor curettage. C. High-speed burr drilling. D. The tumor cavity is filled with gel. E. Cryoablation.

TECH FIG 8 • Cryoablation of the fourth toe using the closed, argonbased system. It would have been difficult to freeze these sites with direct pour of liquid nitrogen due to the relatively large size of the funnels.

P.75

PEARLS AND PITFALLS Surgical considerations

▪ Mobilization of the neurovascular bundle and surrounding soft tissues ▪ Adequately large cortical window ▪ Meticulous curettage followed by high-speed burr ▪ Soft tissue protection and warming throughout cryoablation ▪ Reconstruction of the tumor cavity with cemented hardware and of the subchondral surface with autologous bone graft

Rehabilitation

▪ Protected weight bearing postoperatively

POSTOPERATIVE CARE Routine perioperative prophylactic antibiotics are administered for 3 to 5 days. Patients with lesions of the lower extremities are kept non-weight bearing for 6 weeks. Plain radiographs are then obtained to rule out fracture and establish bone graft incorporation. Gradual weight bearing is allowed if healing had progressed satisfactorily.

OUTCOMES By far, the most extensive experience with cryoablation has involved giant cell tumor of bone, a benign aggressive primary bone tumor. Two-thirds of these lesions occur in the third or fourth decades of life and, in most cases, are located in the metaphyseal-epiphyseal region of long bones around the articular cartilage.19 Because wide excision of such tumors would cause major loss of function due to their proximity to the joint, it had been common practice to opt for intralesional procedures, but it emerged that the rate of local recurrence, mainly after curettage, was unacceptably high, that is, 40% to 55%.8,16,21,43 The use of cryoablation with liquid nitrogen as an adjuvant to curettage and high-speed burr drilling substantially lowered the recurrence rate. Malawer et al27 reported a 2.3% recurrence rate among 86 patients treated primarily with cryoablation. Good to excellent functional outcome was reported in 92% of the patients (FIG 1).27 Because cryoablation provides a nonselective mechanism for cell destruction, it is not surprising that similar rates of local tumor control and associated good functions were reported with other benign aggressive and malignant tumors.3,4,9,14,23,24,25,28,30,31,34,35,37,38,40,44,45,46,49

COMPLICATIONS The observation made by Gage et al13 that cryoablation is a double-edged sword, that is, that it induces tumor necrosis with similar injury to the surrounding normal tissues, was initially underestimated by surgeons who pioneered the application of this technique in clinical practice. Inadequate protection of soft tissues, lack of mechanical fixation, and failure to use perioperative antibiotics resulted in unacceptably high rates of fractures, soft tissue injury, infections, and neurapraxias.32 Those complications gave cryoablation its bad reputation and motivated refinements of the surgical technique to include concomitant soft tissue mobilization and protection, stable reconstruction with cemented internal fixation devices, and the use of perioperative antibiotics. As a result, the same authors reported a later series of patients with a significantly reduced rate of those complications.39,52 Postoperative fractures have been a devastating complication of cryoablation (FIG 2). They were considered pathologic because they occurred through a mechanically weakened bone and following a minor trauma.4,20,27,33,39 These fractures healed slowly (over a period of 3 to 9 months) and were associated with a significant loss of function. Lack of stable fixation and early weight bearing were shown to be the important determinants of these fractures, and the treatment protocol was changed accordingly: The consensus was that cryoablation must be followed by stable reconstruction that includes internal fixation reinforced with PMMA and a strict rehabilitation protocol of gradual weight bearing.27,32,39 This regimen resulted in a minimal rate of postoperative fractures, as reported in the series published from the 1990s to date.4,24,27,44,46,49,50

When such postoperative fractures do occur, surgical intervention is generally not required because the fracture lines are invariably along the internal fixation device and so are not significantly displaced, whereupon immobilization and avoidance of weight bearing are usually sufficient. Infections and flap necrosis have also become rare complications due to mobilization and protection of soft tissues prior to freezing and to the use of perioperative antibiotics.

FIG 1 • Full flexion of the knee in a 54-year-old male 3 months following cryoablation of a chondrosarcoma of the lateral femoral condyle. It would have been difficult to achieve such a range and muscle strength after the distal femur resection that would have otherwise been offered to this patient. P.76

FIG 2 • A. Plain radiograph showing pathologic fracture of the proximal tibia following cryoablation and upon weight bearing. Reconstruction following cryoablation in that patient consisted solely of autologous bone graft only. B. The wide collapse and destruction of the articular surface made resection of the proximal tibia and reconstruction with endoprosthesis inevitable. Mobilization of the neurovascular bundle and surrounding soft tissues away from the tumor site, as well as the use of perioperative antibiotics, resulted in low rates of infections, thermal injuries, and nerve palsies (FIG 3). When the latter do occur, the neurologic damage is usually transient and heals spontaneously. Cryoablation was also shown to be associated with a minimal damage to the adjacent articular cartilage with degenerative changes having occurred in less than 3% in a large series of patients (FIG 4).27 Cryoablation achieves best local tumor control when applied on microscopic disease and in tumors, which have not caused major cortical destruction and invasion into the surrounding soft tissues. Any compromise of one of these criteria may ultimately result in a local tumor recurrence. Better case selection, adequate curettage, and meticulous burr drilling have led to a drop in local recurrence rates to less than 5% in most series.4,24,27,44,46,47,49,51 A second cryoablative procedure is curative in most cases of local recurrence.1,25,27,33,36,44,49,50,51

FIG 3 • Thermal injury to the leg due to spillage of liquid nitrogen. The soft tissues were apparently not well protected in this patient during freezing. This complication is rare when adequate padding and warming with saline are carried out. It is even rarer when using the closed argon-based system that does not involve any poured fluid whatsoever.

FIG 4 • (A) Anteroposterior and (B) lateral radiographs of the knee joint showing considerable degenerative changes of the tibial articular cartilage eight years following cryoablation of giant cell tumor occupying the proximal tibia. Venous gas embolism is a rare complication of open cryoablation with liquid nitrogen, having been reported in only four cases.10,46,47 Liquid nitrogen rapidly produces nitrogen bubbles (N2) at room temperature. Although most of the gas exits into the atmosphere through the surgical wound, a considerable amount is nevertheless pushed into the pulmonary circulation under the influence of the pressure due to boiling of liquid nitrogen in the bony cavity and exhaled.10,47 It is usually manifested intraoperatively with decreased oxygen saturation level and end-tidal carbon dioxide (CO2), associated with a drop in blood pressure and a rise in the heart rate.47 These emboli usually resolve completely with early detection, discontinuation of nitrous oxide administration, and support with oxygen.47

REFERENCES 1. Aboulafia AJ, Rosenbaum DH, Sicard-Rosenbaum L, et al. Treatment of large subchondral tumors of the knee with cryosurgery and composite reconstruction. Clin Orthop Relat Res 1994;307:189-199. 2. Adam M, Hu JF, Lange P, et al. The effect of liquid nitrogen submersion on cryopreserved human heart

valves. Cryobiology 1990;27: 605-614. 3. Athanasian EA, McCormack RR. Recurrent aneurysmal bone cyst of the proximal phalanx treated with cryosurgery: a case report. J Hand Surg 1999;24(A):405-412. 4. Bickels J, Kollender Y, Merimsky O, et al. Closed argon-based cryoablation of bone tumors. J Bone Joint Surg 2004;86(B):714-718. 5. Bickels J, Meller I, Shmookler BM, et al. The role and biology of cryosurgery in the treatment of bone tumors. A review. Acta Orthop Scand 1999;70:308-315. 6. Bickels J, Rubert CK, Meller I, et al. Cryosurgery in the treatment of bone tumors. Oper Techn Orthop 1999;9:79-83. 7. Bischof JC, Rubinsky B. Large ice crystals in the nucleus of rapidly frozen liver cells. Cryobiology 1993;30:597-603. 8. Campanacci M, Baldini N, Boriani S, et al. Giant cell tumor of bone. J Bone Joint Surg Am 1987;69:106114. 9. De Vries J, Oldhoff J, Hadders HN. Cryosurgical treatment of sacrococcygeal chordoma. Report of four cases. Cancer 1986;58:2348-2354. 10. Dwyer DM, Thorne AC, Healey JH, et al. Liquid nitrogen instillation can cause venous gas embolism. Anesthesiology 1990;73:181-183. P.77 11. Gage AA, Augustynowicz S, Montes M, et al. Tissue impedence and temperature measurements in relation to necrosis in experimental cryosurgery. Cryobiology 1985;22:282-288. 12. Gage AA, Baust J. Mechanisms of tissue injury in cryosurgery. Cryobiology 1998;37:171-186. 13. Gage AA, Greene GW, Neiders ME, et al. Freezing bone without excision. An experimental study of bone cell destruction and manner of regrowth in dogs. JAMA 1966;196:770-774. 14. Gartsman GM, Ranawat CS. Treatment of osteoid osteoma of the proximal phalanx by use of cryosurgery. J Hand Surg 1984;9(A):275-277. 15. Gill W, Fraser J, Carter DC. Repeated freeze-thaw cycles in cryosurgery. Nature 1968;219:410-413. 16. Goldenberg R, Campbell C, Bonfiglio M. Giant cell tumor. An analysis of 219 cases. J Bone Joint Surg Am 1970;52:619-664. 17. Griffiths JB. Effect of hypertonic stress on mammalian cell lines and its relevance to freeze-thaw injury. Cryobiology 1978;15:517-529.

18. Heard BE. The histological appearances of some normal tissues at low temperatures. Br J Surg 1955;42:430-437. 19. Huvos GA. Giant cell tumor of bone. In: Huvos GA, ed. Bone Tumors: Diagnosis, Treatment, and Prognosis, ed 2. Baltimore: W.B. Saunders 1991:429-467. 20. Jacobs PA, Clemency RE. The closed cryosurgical treatment of giant cell tumor. Clin Orthop Relat Res 1985:192:149-158. 21. Johnson EW, Dahlin DC. Treatment of giant cell tumor of bone. J Bone Joint Surg Am 1959;41:895-904. 22. Keijser LC, Schreuder HW, Buma P, et al. Cryosurgery in long bones; an experimental study of necrosis and revitalization in rabbits. Arch Orthop Trauma Surg 1999;119:440-444. 23. Keijser LC, van Tienen TG, Schreuder HW, et al. Fibrous dysplasia of bone: management and outcome of 20 cases. J Surg Oncol 2001;76:157-166. 24. Kollender Y, Bickels J, Price WM, et al. Metastatic renal cell carcinoma of bone: indications and technique of surgical intervention. J Urol 2000;164:1505-1508. 25. Kollender Y, Meller I, Bickels J, et al. Role of adjuvant cryosurgery in intralesional treatment of sacral tumors. Results of a 3 11-year follow-up. Cancer 2003;97:2830-2838. 26. Kuylenstierna R, Lundquist PG. Bone destruction by direct cryoapplication: a temperature study in rabbits. Cryobiology 1982;19:231-236. 27. Malawer MM, Bickels J, Meller I, et al. Cryosurgery in the treatment of giant cell tumor. A long-term follow-up study. Clin Orthop Relat Res 1999;359:176-188. 28. Malawer MM, Dunham W. Cryosurgery and acrylic cementation as surgical adjuncts in the treatment of aggressive (benign) bone tumors. Analysis of 25 patients below the age of 21. Clin Orthop Relat Res 1991;262:42-57. 29. Malawer MM, Marks MR, McChesney D, et al. The effect of cryosurgery and polymethylmethacrylate in dogs with experimental bone defects comparable to tumor defect. Clin Orthop Relat Res 1988;226:299-310. 30. Malawer MM, Vance R. Giant cell tumor and aneurysmal bone cyst of the talus: clinicopathological review and two case reports. Foot Ankle 1981;1:235-244. 31. Marcove RC. A 17-year review of cryosurgery in the treatment of bone tumors. Clin Orthop Relat Res 1982;163:231-234. 32. Marcove RC, Lyden JP, Huvos AG, et al. Giant cell tumors treated by cryosurgery. A report of twenty-five cases. J Bone Joint Surg Am 1973;55:1633-1644.

33. Marcove RC, Miller TR. Treatment of primary and metastatic bone tumors by cryosurgery. JAMA 1969;207:1890-1894. 34. Marcove RC, Sadrieh J, Huvos AG, et al. Cryosurgery in the treatment of solitary or multiple bone metastases from renal cell carcinoma. J Urol 1972;108:540-547. 35. Marcove RC, Searfoss RC, Whitmore WF, et al. Cryosurgery in the treatment of bone metastases from renal cell carcinoma. Clin Orthop Relat Res 1977;127:220-227. 36. Marcove RC, Sheth DS, Brien EW, et al. Conservative surgery for giant cell tumors of the sacrum. The role of cryosurgery as a supplement to curettage and partial excision. Cancer 1994;74:1253-1260. 37. Marcove RC, Sheth DS, Takemoto S, et al. The treatment of aneurysmal bone cyst. Clin Orthop Relat Res 1995;311:157-163. 38. Marcove RC, Stovell PB, Huvos AG, et al. The use of cryosurgery in the treatment of low and medium grade chondrosarcoma. Clin Orthop Relat Res 1977;122:147-156. 39. Marcove RC, Weis LD, Vaghaiwalla MR, et al. Cryosurgery in the treatment of giant cell tumor of bone. A report of 52 consecutive cases. Cancer 1978;41:957-969. 40. Marcove RC, Zahr KA, Huvos AG, et al. Cryosurgery in osteogenic sarcoma: report of three cases. Cancer 1984;10:52-60. 41. Mazur P. Cryobiology: the freezing of biological systems. Science 1970;168:939-949. 42. Mazur P. Freezing of living cells: mechanisms and implications. Am J Physiol 1984;143:125-142. 43. McDonald DJ, Sim FH, McLeod RA, et al. Giant cell tumor of bone. J Bone Joint Surg Am 1986;68:235242. 44. Schreuder HW, Conrad EU III, Bruckner JD, et al. Treatment of simple bone cysts in children with curettage and cryosurgery. J Pediatr Orthop 1997;17:814-820. 45. Schreuder HW, Pruszczynski M, Lemmens JA, et al. Eosinophilic granuloma of bone: results of treatment with curettage, cryosurgery, and bone grafting. J Pediatr Orthop 1998;7(B):253-256. 46. Schreuder HW, Pruszczynski M, Veth RP, et al. Treatment of benign and low-grade malignant intramedullary chondroid tumours with curettage and cryosurgery. Eur J Surg Oncol 1998;24:120-126. 47. Schreuder HW, van Beem HB, Veth RP. Venous gas embolism during cryosurgery for bone tumors. J Surg Oncol 1995;60:196-200. 48. Schreuder HW, van Egmond J, van Beem HB, et al. Monitoring during cryosurgery of bone tumors. J

Surg Oncol 1995;65:40-45. 49. Schreuder HW, Veth RP, Pruszczynski M, et al. Aneurysmal bone cysts treated by curettage, cryotherapy and bone grafting. J Bone Joint Surg Br 1997;79:20-25. 50. Segev E, Kollender Y, Bickels J, et al. Cryosurgery in fibrous dysplasia. Good result of a multimodality protocol in 16 patients. Acta Orthop Scand 2002;73:483-486. 51. Sheth DS, Healey JH, Sobel M, et al. Giant cell tumor of the distal radius. J Hand Surg 1995;20(A):432440. 52. Willert HG. Clinical results of the temporary acrylic bone cement plug in the treatment of bone tumors: a multicentric study. In: Enneking WF, ed. Limb-Sparing Surgery in Musculoskeletal Oncology. New York: Churchill Livingstone, 1987:445-448.

Chapter 7 Photodynamic Ablation of Musculoskeletal Tumors Jacob Bickels Yair Gortzak Yehuda Kollender

BACKGROUND Malignant tumors of the musculoskeletal system, as many other solid tumors, require a true and wide surgical resection for their complete removal. The term wide margins currently used by orthopaedic and surgical oncologist refers to the margins of normal tissue surrounding a visible tumor mass, usually a few centimeters in thickness. However, such resection does not guarantee cure as microscopic disease is left throughout the surgical field beyond this wide cuff of tissue. Adjuvant treatments for surgery are, therefore, required, and patients who undergo resection of malignant musculoskeletal tumors are usually referred for treatment with radiation therapy and/or chemotherapy upon their recovery from surgery. These adjuvant treatment modalities were shown to be effective in lowering the likelihood of local tumor recurrence. However, they are associated with a most considerable rate of complications, local and systemic, as they are not tissue specific and harm healthy tissues and organs as well.

INDICATIONS Photodynamic ablation (PDA) allows specific tumor kill and therefore may provide a treatment option for the microscopic disease remaining in the surgical field following tumor removal. It is defined as the administration of a nontoxic drug or dye, known as a photosensitizer (PS), either systemically, locally, or topically to a patient bearing a tumor. The PS has specific affiliation to the tumoral tissue, and following its accumulation within the tumor cells, the tumor site is illuminated with a visible light, which excites the PS to generate cytotoxic species and consequently cause tumor cell death and destruction of tumor. The realization that the combination of nontoxic dyes and visible light could kill cells was first made by Oscar Raab, a medical student working with Professor Herman Von Tappeiner in Munich in 1900. While investigating the effects of acridine dyes on the protozoa that causes malaria, he made an incidental discovery that the combination of acridine red and light resulted in protozoal death.12 He postulated that the effect was caused by the transfer of energy from light to the chemical, similar to the process of photosynthesis seen in plants after the absorption of light by chlorophyll. This discovery led to the first therapeutic medical application in which topical eosin, combined with white light illumination, were used to treat various skin tumors. It was soon realized that oxygen is required to allow this chain of reactions, and the term photodynamic action was used to describe this phenomenon.

ANATOMIC CONSIDERATIONS Over the last few decades, PDA has been studied and used in a large variety of tumors. However, the use of PDA in the field of orthopaedic oncology was practiced only by a small group of enthusiastic surgeons. Matsubara et al10 reported on eight patients who had either bone or soft tissue sarcomas of the forearm and underwent intralesional resection of their tumor followed by PDA using topical administration of acridine

orange (AO). Destruction of the microscopic disease that was left in the surgical field was done in three consecutive steps: 1. The surgical field is illuminated with blue light, which excites the AO within the residual tumoral tissue to emit green fluorescence. The tissue emitting this green fluorescence is detected with a designated surgical microscope and removed using an ultrasonic surgical scalpel. 2. Illumination of the surgical field with unfiltrated light from a xenon lamp 3. Single session of radiation therapy at a dose of 5 Gy, given immediately after surgery This group of 8 patients was compared to another group of 10 patients who underwent wide tumor resection with adjuvant radiation therapy. The rates of local tumor recurrence were 12.5% and 20%, respectively, and patients who underwent marginal tumor resection with PDA had considerably better function.2 We are currently studying the use of PDA with 5-aminolevulinic acid (5-ALA) in the management of desmoid tumor and other benign and malignant soft tissue tumors, which have fibrous element in their structure. Desmoid tumors, also known as fibromatoses, are locally aggressive, soft tissue lesions. Extra-abdominal lesions appear between puberty and the sixth decade of life, with the peak incidence between 25 and 35 years of age. These lesions are located in a variety of anatomic sites, with the shoulder girdle, chest wall, back, and thighs being the most frequent locations in descending order.7 Although desmoid tumors do not metastasize, they are locally infiltrative and their propensity for local recurrence following wide resection is well documented. Although wide local resection still remains the treatment of choice for the majority of patients, the postoperative local recurrence rates were reported to be as high as 30% and 33% at the 5- and 10-year posttreatment follow-ups, respectively.1 Rock et al13 reported 194 patients with desmoid tumor who were treated at the Mayo Clinic, of whom 132 (68%) had a local tumor recurrence. Positive margins of the resection are considered a strong predictor for local tumor recurrence.1,6 A locally recurrent desmoid tumor is a devastating clinical event. It usually requires extensive surgery for its removal and usually mandates adjunctive treatment (radiation therapy and/or chemotherapy). It is also associated with a P.79 considerable loss of function and impaired quality of life. Because recurrence rates are so closely related to residual tumor tissue and positive margins of the resection, elimination of the microscopic disease left in the surgical field following wide tumor resection is key to lowering these high rates of tumor recurrence (FIG 1).

FIG 1 • Recurrent tumors are related to the presence of microscopic disease left in the surgical field following wide resection of the main tumoral mass. The formation of 5-ALA from glycine and succinyl coenzyme A (CoA) is the first step of the heme biosynthetic pathway, which ends with the incorporation of iron into protoporphyrin IX (PpIX). Due to enzymatic abnormalities occurring along this pathway in some tumors, exogenous administration of 5-ALA results in the accumulation of PpIX, which is an efficient PS (FIG 2).11 When cells and tissue specimens that had been photosensitized with 5-ALA-induced PpIX are exposed to blue light at a wavelength of 420 nm, pink fluorescence can be detected—a finding which allows intraoperative identification and enhanced resection of these tumors.11 This effect was used to improve the margins of resection in ovarian carcinomas and glioblastomas.8,14 Furthermore, exposure of cells that have accumulated PpIX to red light (635 nm) achieved a cytotoxic effect, which can be exploited for photodynamic therapy (FIG 3).11 This 5-ALA characteristic has already been implemented in the management of skin tumors, bladder cancer, tumors of the oral cavity, and high-grade dysplasias and carcinomas of the esophagus.3,4,5,9

FIG 2 • Due to enzymatic abnormalities, exogenous administration of 5-aminolevulinic (5-ALA) to tumor cells results in intracellular accumulation of protoporphyrin IX (PpIX), a potent PS. GLY, Glycine; SCoA, SuccinylCoenzyme A; PBG, Porphobilinogen; URO, Uroporphyrinogen; PROTO, Protoporphyrinogen; COPRO, Coproporphyrinogen.

FIG 3 • Exposure of intracellular protoporphyrin IX (PpIX) to blue light at a wavelength of 420 nm results in pink fluorescence. Its exposure to red light (635 nm), however, induces a cytotoxic effect, which can be exploited for photodynamic therapy.

OUTCOMES The results of our recent pilot clinical study revealed that preoperative administration of 5-ALA (20 mg/kg) to five patients diagnosed as having desmoid tumor resulted in a considerable intracellular accumulation of PpIX. Pink fluorescence was clearly evident in all the study patients upon the illumination of the resected tumor with a blue light. Pink fluorescence, however, was not evident within the surgical field probably due to the microscopic size of the residual disease. At their most recent follow-up, all study patients had local tumor recurrence. The results of this study were presented at several international meetings. Based on our earlier findings, we applied for approval to run a second clinical study with the aim of

treating desmoid tumors with 5-ALA-based photoablation. Briefly, the proposed study protocol includes oral administration of 5-ALA (60 mg/kg) 3 hours before surgery (FIG 4). The tumor is resected according to standard procedures. After tumor removal, the surgical specimen is illuminated with blue light (420 nm) to verify the presence of PpIX within the tumoral tissue (FIG 5). The surgical field is then illuminated with red light (635 nm, light dose of 150 J/cm2), which induces the killing of the remaining microscopic disease (FIGS 6,7 and 8). P.80

FIG 4 • 5-ALA (60 mg/kg) is given orally 3 hours before surgery.

FIG 5 • The resected tumor is illuminated with blue light (420 nm) to verify the presence of PpIX within the tumoral tissue.

FIG 6 • The surgical field is illuminated with red light (635 nm, light dose of 150 J/cm2) to induce the killing of the remaining microscopic disease. P.81

FIG 7 • A. Magnetic resonance scan showing desmoid tumor of the lateral arm. B. Intraoperative photograph showing the surgical field following resection of the tumoral mass; the humeral diaphysis is exposed. C. The tumor is opened to expose the neoplastic tissue. D. A strong pink fluorescence is evident following illumination with blue light. E. A designated red light source is positioned in front of the surgical field. F. The surgical field is illuminated with red light (635 nm, light dose of 150 J/cm2) for approximately 30 minutes to induce the killing of the remaining microscopic disease. P.82

FIG 8 • A,B. Medium-grade fibrosarcoma of the right flank. C. The tumor is opened to expose the neoplastic tissue. D. A strong pink fluorescence is evident following illumination with blue light. As in the case shown in FIG 7, following the detection of pink fluorescence in the resected tumor, the surgical field was illuminated with red light. The use of 5-ALA-based photoablation of desmoid tumor is an ongoing study, the preliminary results of which will be published in 2 years. We similarly use 5-ALA-based photoablation in the management of chondromyxoid fibroma, dermatofibrosarcoma protuberans, solitary fibrous tumors, and fibrosarcomas.

REFERENCES 1. Ballo MT, Zagars GK, Pollack A, et al. Desmoid tumor: prognostic factors and outcome after surgery, radiation therapy, or combined surgery and radiation therapy. J Clin Oncol 1999;17:158-167. 2. Blume JE, Oseroff AR. Aminolevulinic acid photodynamic therapy for skin cancers. Dermatol Clin 2007;25:5-14.

3. Denzinger S, Burger M, Walter B, et al. Clinically relevant reduction in risk of recurrence of superficial bladder cancer using 5-aminolevulinic acid-induced fluorescence diagnosis: 8-year results of prospective randomized study. Urology 2007;69:675-679. 4. Fan KF, Hopper C, Speight PM, et al. Photodynamic therapy using 5-aminolevulinic acid for premalignant and malignant lesions of the oral cavity. Cancer 1996;78:1374-1383. 5. Gossner L, May A, Sroka R, et al. Photodynamic destruction of high-grade dysplasia and early carcinoma of the esophagus after the oral administration of 5-aminolevulinic acid. Cancer 1999;86; 1921-1928. 6. Gronchi A, Casali PG, Mariani L, et al. Quality of surgery and outcome in extra-abdominal aggressive fibromatosis: a series of patients surgically treated at a single institution. J Clin Oncol 2003;21:1390-1397. 7. Hosalkar HS, Torbert JT, Fox EJ, et al. Musculoskeletal desmoid tumors. J Am Acad Orthop Surg 2008;16:188-198. 8. Löning M, Diddens H, Küpker W, et al. Laparoscopic fluorescence detection of ovarian carcinoma metastases using 5-aminolevulinic acid-induced protoporphyrin IX. Cancer 2004;100:1650-1656. 9. Mackenzie GD, Dunn JM, Selvasekar CR, et al. Optimal conditions for successful ablation of high-grade dysplasia in Barrett's esophagus using aminolaevulinic acid photodynamic therapy. Laser Med Sci 2009;24:729-734. 10. Matsubara T, Kusuzaki K, Matsumine A, et al. Clinical outcome of minimally invasive surgery using acridine orange for musculoskeletal sarcomas around the forearm, compared with conventional limb salvage surgery after wide resection. J Surg Oncol 2010;102:271-275. 11. Peng Q, Warloe T, Berg K, et al. 5-Aminolevulinic acid-based photodynamic therapy. Clinical research and future challenges. Cancer 1997;79:2282-2308. 12. Raab O. Uber die wirkung fluoreszierender stoffe auf infusorien. Z. Biol 1900;39:524-526. 13. Rock MG, Pritchard DJ, Reiman HM, et al. Extra-abdominal desmoid tumors. J Bone Joint Surg Am 1984;66:1369-1374. 14. Stummer W, Pichlmeier U, Meinel T, et al. Fluorescence-guided surgery with 5-aminolevulinic acid for resection of malignant glioma: a randomized controlled multicenter phase III trial. Lancet Oncol 2006;7:392401.

Chapter 8 Overview of Resections around the Shoulder Girdle James C. Wittig Martin M. Malawer Kristen Kellar-Graney

BACKGROUND The upper extremity is involved by bone and soft tissue neoplasms only one-third as often as the lower extremity.3 The scapula and proximal humerus are common sites of primary sarcoma, including osteosarcoma and Ewing sarcoma in children and chondrosarcoma in adults. Metastatic tumors, especially hypernephroma, also have a propensity for the proximal humerus. When soft tissue tumors occur in the upper extremity, they tend to favor the shoulder girdle and may secondarily involve the scapula, proximal humerus, or clavicle. The axilla is another site around the shoulder girdle where primary soft tissue tumors may develop or where metastases can spread to and replace the local lymph nodes. The axilla is a relatively “silent” area, where tumors may grow to large sizes before they become symptomatic and are detected. The shoulder girdle consists of the proximal humerus, the scapula, and the distal third of the clavicle as well as the surrounding soft tissues. Each bone may be involved by a primary malignant bone tumor or metastases, with or without soft tissue extension. The bones of the shoulder girdle also may be secondarily involved by a soft tissue sarcoma, which requires resection and reconstruction techniques similar to those of a primary bone tumor (FIG 1). Until the mid-20th century, forequarter amputation was the treatment for malignant tumors of the shoulder girdle. Today, about 95% of patients with sarcomas of the shoulder girdle can be treated safely by limbsparing resection such as the Tikhoff-Linberg resection and its modifications.6 The relation of the neurovascular bundle to the tumor and other structures of the shoulder girdle is the most significant anatomic factor in determining resectability, removal of the tumor, and reconstruction. The resection and reconstruction of tumors of the shoulder girdle consists of three components: Surgical resection of the tumor following oncologic principles Reconstruction of the skeletal defect (ie, endoprosthetic replacement) Soft tissue reconstruction using multiple muscle transfers to cover the skeletal reconstruction and provide a functional extremity The goals of all shoulder girdle reconstructions are to provide a stable shoulder and to preserve normal elbow and hand function. The extent of tumor resection and remaining motor groups available for reconstruction dictate the degree of shoulder motion and function that are retained.

Historical Background Some of the earliest discussions concerning limb-sparing surgery focused on techniques for resection of tumors about the scapula. Initial reports of shoulder girdle resections were confined to the individual bones or portions of the scapula. The first reported scapular resection was a partial scapulectomy performed by Liston in 18197 for an ossified aneurysmal tumor. Between this time and the mid-1960s, several other authors discussed limb-sparing resections about the shoulder girdle.4,11,12,13,14,15,16,19 In 1965, Papioannou and

Francis17 reported 26 scapulectomies and discussed the indications and limitations of the procedure. The Tikhoff-Linberg interscapulothoracic resection or triple-bone resection was described in the Russian literature by Baumann1 in 1914. He referred to a 1908 report by Pranishkov that described the removal of the scapula, the head of the humerus, the outer one-third of the clavicle, and the surrounding soft tissue for a sarcoma of the scapula. The shoulder was suspended from the remaining clavicle by metal sutures. Tikhoff and Baumann performed three such operations between 1908 and 1913, and Tikhoff was named as the originator of the procedure. The technique became established in the Western surgical community only after Linberg's English publication in 1926.6 Classically, most shoulder girdle resections were done for low-grade tumors of the scapula and for periscapular soft tissue sarcomas. Before 1970, most patients with high-grade spindle cell sarcomas (eg, osteosarcoma, chondrosarcoma) involving the shoulder girdle were treated with a forequarter amputation. In 1977, Marcove et al12 were the first to report limb-sparing surgery for high-grade sarcomas arising from the proximal humerus. These authors reported performing an en bloc extra-articular resection that included the proximal humerus, glenoid, overlying rotator cuff, lateral two-thirds of the clavicle, deltoid, coracobrachialis, and proximal biceps. Local tumor control and survival rates were similar to those achieved with a forequarter amputation. Resection, however, preserved a functional hand and elbow. These early results were confirmed by other surgeons.5,18 After the 1980s, osteosarcoma, chondrosarcoma, and Ewing sarcoma of the proximal humerus became the tumors most commonly treated with a Tikhoff-Linberg resection. A variety of new techniques and modifications of shoulder girdle resections have been developed. Most have been reported as Tikhoff-Linberg or modified Tikhoff-Linberg resections. These eponyms are not accurate descriptions, however, because the Tikhoff-Linberg procedure was not intended to refer to sarcomas of the humerus. As the popularity of limb-sparing surgery for shoulder girdle sarcomas grew, the extent of resection necessary for various tumors, particularly indications for an extra-articular resection, remained a matter of debate. The best method for reconstruction also came under considerable discussion. P.84 In response, Malawer et al developed a surgical classification system (FIG 2) based on tumor location, extent, grade, and pathologic type. This system was intended to provide guidelines regarding the extent of resection necessary for primary bone sarcomas and soft tissue sarcomas that secondarily involve the bones of the shoulder girdle.

FIG 1 • Three-dimensional schematic drawing of the shoulder girdle and axillary contents. The brachial plexus and axillary artery and vein are demonstrated coursing through the axillary space. The proximal humerus, clavicle, and scapula are seen here. The musculature of the axillary space forms the borders of the compartment, including the pectoralis major, latissimus dorsi, short head of the biceps, and clavicle. (Courtesy of Martin M. Malawer.)

SURGICAL CLASSIFICATION SYSTEM The current surgical classification system was described by Malawer and associates2,8,9,10 in 1991 (see FIG 2). It is based on the current concepts of surgical margins, the relation of the tumor to anatomic compartments (ie, intracompartmental vs. extracompartmental), the status of the glenohumeral joint, the magnitude of the individual surgical procedure, and precise considerations of the functionally important soft tissue components. It includes six categories: Type I: intra-articular proximal humeral resection Type II: partial scapular resection Type III: intra-articular total scapulectomy

Type IV: extra-articular total scapulectomy and humeral head resection (classic Tikhoff-Linberg resection) Type V: extra-articular humeral and glenoid resection Type VI: extra-articular humeral and total scapular resection Each type is subdivided according to the status of the abductor mechanism (the deltoid muscle and rotator cuff): Abductors intact Abductors partially or completely resected Type A resections, in which the abductors are preserved, usually are recommended for high-grade spindle cell bone sarcomas that are entirely intracompartmental (ie, contained within either the proximal humerus or scapula bone). This is a rare situation, however. This type of resection also is recommended for low-grade bone sarcomas, selected metastatic carcinomas, and, often, round cell sarcomas. Type B resections, in which the abductors are resected, are extracompartmental resections and are the most common type of resection performed for high-grade spindle cell sarcomas. All six of these types of shoulder girdle resections and their indications are described briefly in the following section. The surgical techniques for each resection and reconstruction are described in Chapters 9, 10, and 11,12 and 13 in this section.

GUIDELINES FOR SHOULDER GIRDLE RESECTION Local Growth and Transarticular Involvement by Shoulder Girdle Tumors The shoulder joint appears to be more prone than other joints to intra-articular or pericapsular (ligamentous) involvement by high-grade bone sarcomas. Four basic mechanisms underlie tumor spread across the shoulder joint: direct capsular extension, tumor extension along the long head of the biceps tendon, fracture hematoma from a pathologic fracture, and poorly planned biopsy (FIG 3). These mechanisms place patients undergoing intra-articular resections for high-grade sarcomas at greater risk for local recurrence than those undergoing extra-articular resections. Therefore, it often is necessary to perform an extra-articular resection for high-grade bone sarcomas of the proximal humerus or scapula. Most tumors arise from the metaphyseal portion of the proximal humerus. They extend beyond the cortices and spread underneath the deltoid muscle, subscapularis muscle, and remaining rotator cuff muscles. As the tumor grows, the extraosseous component spreads along the long head of the biceps tendon, along the glenohumeral ligaments, and underneath the rotator cuff, heading toward the glenoid or directly crossing the glenohumeral joint. The deltoid, subscapularis, and remaining rotator cuff muscles are compressed into a pseudocapsular layer. These muscles form compartmental boundaries around the tumor. The axillary nerve and circumflex vessels enter this compartment. The major neurovascular bundle is displaced by the tumor; however, in most instances, the fascia overlying the subscapularis muscle as well as the axillary sheath that contains the blood vessels and nerves protect the major neurovascular bundle from tumor involvement or encasement. Similarly, most scapular sarcomas originate from the metaphyseal portion of the scapula or the scapula neck and grow centripetally into the soft tissues. They form a soft tissue mass that extends outward and usually is contained by the subscapularis and other rotator cuff muscles. These tumors follow the path of least resistance and are directed toward the glenohumeral joint and proximal humerus. Eventually, the tumor

contaminates these structures. The subscapularis muscle and its investing fascia function as a barrier and protect the axillary vessels and brachial plexus from tumor invasion. These neurovascular structures usually are displaced by the adjacent tumor that lies deep to the subscapularis muscle. P.85

FIG 2 • Classification of shoulder girdle resections as reported by Malawer in 1991. (Reprinted with permission from Malawer MM, Meller I, Dunham WK. A new surgical classification system for shoulder-girdle resections. Analysis of 38 patients. Clin Orthop Relat Res 1991;267:33-44.)

Functional Anatomic Compartment of the Shoulder Girdle Sarcomas grow locally in a centripetal manner and compress surrounding tissues (muscles) into a pseudocapsular layer. The pseudocapsular layer contains microscopic fingerlike projections of tumor, which are referred to as satellite nodules.

FIG 3 • Biopsy site. Anatomic drawing illustrating the preference for a core needle biopsy for tumors of the proximal humerus. The biopsy sample should betaken through the anterior third of the deltoid. Great care should be taken to avoid the pectoralis major muscle, the deltopectoral interval, and the axillary vessels. The deltoid is innervated by the axillary nerve posteriorly, so a portion of the anterior deltoid can be resected if necessary without significant compromise to the nerve. (Courtesy of Martin M. Malawer. From Bickels J, Jellnek S, Shmookler BM, et al. Biopsy of musculoskeletal tumors. Current concepts. Clin Orthop Relat Res 1999;368:212-219.) Sarcomas spread locally along the path of least resistance. Surrounding fascial layers resist tumor penetration and, therefore, provide boundaries to local sarcoma growth. These boundaries form a compartment around the tumor (FIG 4). A sarcoma will grow to fill the compartment in which it arises, and only rarely will an extremely large sarcoma P.86 extend beyond its compartmental borders. In discussing bony sarcomas that extend beyond the cortices into the surrounding soft tissues, the term functional anatomic compartment refers to the investing muscles that are compressed into a pseudocapsular layer (see FIG 4).

FIG 4 • Schematic diagram of the compartment of the proximal humerus. A true compartmental site includes the muscles of origin and insertion of a specific group as well as a major feeding vessel and nerve. This is a conceptual consideration for tumors around the proximal humerus, which does not fit the classic definition of an anatomic compartment. Surgically, however, this area is considered as the shoulder girdle compartment, which consists of the deltoid, the rotator cuff muscles, a portion of the pectoralis major muscle, the latissimus dorsi, and the teres major. The major neurovascular pedicle is the axillary nerve and the circumflex vessels. (Courtesy of Martin M. Malawer. From Wittig JC, Bickels J, Kellar-Graney KL, et al. Osteosarcoma of the proximal humerus: long-term results with limb-sparing surgery. Clin Orthop Relat Res 2002;[397]:156-176.) These muscles provide the fascial borders of the compartment, a fact that has important surgical implications. A wide resection of a bone sarcoma removes the entire tumor and pseudocapsular layer and must, therefore, encompass the investing muscle layers (compartmental resection). The functional compartment surrounding the proximal humerus consists of the deltoid, subscapularis, and remaining rotator cuff, latissimus dorsi (more distally), brachialis, and portions of the triceps muscles. The glenoid and scapular neck also reside within the functional compartment of the proximal humerus because they are contained by the rotator cuff and capsule and the subscapularis muscle. Sarcomas that arise from the proximal humerus and extend beyond the cortices compress these muscles into a pseudocapsular layer. The fascial layers surrounding these muscles resist tumor penetration. The only neurovascular structures that enter this compartment are the axillary nerve and humeral circumflex vessels. The main neurovascular bundle (ie, brachial plexus and axillary vessels) to the upper extremity passes anterior to the subscapularis and latissimus dorsi muscles. These muscles and their investing fascial layers are particularly important, therefore, for protecting the neurovascular bundle from tumor involvement. They also protect the pectoralis major muscle, which must be preserved during surgical resection for soft tissue coverage. High-grade sarcomas that extend beyond the bony cortices of the proximal humerus expand the investing

muscles that form the compartmental borders and pseudocapsular layer. These sarcomas grow along the path of least resistance and, therefore, are directed toward the glenoid and scapular neck by the rotator cuff and glenohumeral joint capsule. Anteriorly, the tumor is covered by the subscapularis, which bulges into and displaces the neurovascular bundle. Only rarely does a very large proximal humerus sarcoma extend beyond the compartmental borders. In these instances, the tumor usually protrudes through the rotator interval. A wide (compartmental) resection for a high-grade sarcoma must, therefore, include the surrounding muscles that form the pseudocapsular layer (ie, deltoid, lateral portions of the rotator cuff), the axillary nerve, humeral circumflex vessels, and the glenoid (extra-articular resection of the proximal humerus). Most high-grade scapular sarcomas arise from the region of the scapular neck. The compartmental borders surrounding the scapular neck consist of the rotator cuff muscles and portions of the teres major and latissimus dorsi muscles. The compartment consists of all of the muscles that originate on the anterior and posterior surfaces of the scapula: the subscapularis, infraspinatus, and teres muscles. The deltoid, although it is not typically considered one of the compartmental borders because it attaches to a narrow region of the scapular spine and acromion, may be involved secondarily by a large soft tissue extension. In most instances, the deltoid is protected by the rotator cuff muscles because the anatomic origin of most tumors is from the neck and body region. Similar to the proximal humerus, the rotator cuff muscles are compressed into a pseudocapsular layer by sarcomas that arise from the scapula. The subscapularis also protects the neurovascular bundle from tumor involvement. The head of the proximal humerus is contained within the compartment surrounding the scapula by the rotator cuff muscles. Wide resection of a high-grade scapular sarcoma must, therefore, include the rotator cuff and, in most instances, the humeral head. The axillary nerve is not contained within the compartment and therefore can be spared from resection. Additionally, because the deltoid is not compressed into a pseudocapsular layer, it usually can be preserved.

INDICATIONS Indications for Limb Sparing Surgery Selection of patients for limb-sparing surgery is based on the anatomic location of the tumor and a thorough understanding of the natural history of sarcomas and other malignancies: High-grade and some low-grade bone sarcomas Soft tissue sarcomas arising from the shoulder girdle Metastatic carcinomas: isolated metastasis or metastatic lesions that have caused significant bony destruction Occasionally, benign aggressive tumors also may require these treatment techniques. P.87

Contraindications for Limb Sparing Surgery Absolute contraindications for limb-sparing procedures include tumor involvement of the neurovascular bundle or a patient's inability or unwillingness to tolerate a limb-sparing operation. Relative contraindications may include chest wall extension; pathologic fracture around the shoulder girdle; previous infection; lymph node involvement; or a complicated, inappropriately placed biopsy that has resulted in extensive hematoma, which has resulted in tissue contamination. Biopsy Site

One of the most common causes for forequarter amputation is an inappropriately placed biopsy site that has resulted in contamination of the pectoralis muscles, neurovascular structures, and chest wall. Extreme care must be taken with biopsy placement and technique (see FIG 3). Vascular Involvement Fortunately, most tumors of the proximal humerus are separated from the anterior vessels by the subscapularis, latissimus dorsi, and coracobrachialis muscles. It is rare for the axillary or brachial artery to be involved with tumor, although a large soft tissue component may cause displacement and compression. In general, if the vessels appear to be involved with tumor, the adjacent brachial plexus also is involved, and a limbsparing procedure may be contraindicated. Nerve Involvement The three major cords of the brachial plexus follow the artery and vein and rarely are involved with tumor. The axillary nerve may be involved by neoplasm as it passes from anterior to posterior along the inferior glenohumeral joint capsule. Resection of the axillary nerve usually is required for stage IIB tumors of the proximal humerus. The musculocutaneous and radial nerves rarely are involved. The deficit created by resecting the radial nerve is greater than that for the musculocutaneous nerve, but this should not be an indication for amputation. If resection will lead to a major functional loss and a close margin (increasing the risk of local recurrence), amputation should be considered. Direct tumor extension into or encasement of the brachial plexus necessitates a forequarter amputation. Lymph Nodes Bone sarcomas rarely involve adjacent lymph nodes; nevertheless, axillary nodes should be evaluated and may require biopsy. In the rare incidence of lymph node involvement documented by biopsy, a forequarter amputation may be the best method for removing all gross disease. Alternatively, a lymph node dissection in conjunction with a limb-sparing procedure may be considered. Malawer (unpublished data, 2009) has found, based on two cases, that local control and long-term survival can be obtained by this method. Chest Wall Involvement Tumors of the shoulder girdle with large extraosseous components occasionally may involve the chest wall, ribs, and intercostal muscles. Chest wall involvement should be evaluated preoperatively with physical examination and imaging studies; however, such involvement often is not determined until the time of surgery. It is not an absolute indication for forequarter amputation; a limb-sparing procedure combined with a chest wall resection may be performed, depending on the involvement of adjacent soft tissues and neurovascular structures. Previous Resection The local recurrence rate is increased in cases in which a wide resection is attempted (1) following a previous inadequate resection around the shoulder girdle or (2) when a tumor already has recurred locally. This possibility must be a consideration especially with tumors of the scapula and clavicle and of soft tissue tumors that involve the proximal humerus. Infection In patients with high-grade sarcomas, limb-sparing procedures performed in an area of infection are

extremely risky because these patients must receive postoperative adjuvant chemotherapy. If an infection cannot be eradicated with the primary resection, amputation is advisable.

SURGICAL MANAGEMENT Preoperative Planning Physical Examination The physical examination is essential for assessing tumor resectability and for estimating the extent of resection that may be required. Physical examination is important in determining tumor extension into the glenohumeral joint, neurovascular involvement, or tumor invasion of the chest wall. If tumor has invaded the joint, shoulder range of motion usually is reduced, and the patient may complain about discomfort and pain. Neurovascular involvement or compression may be suggested by an abnormal neurologic examination or by decreased or absent pulses. Distal edema in the upper extremity means a probable tumoral infiltration in neurovascular structures. Tumors that move freely with respect to the chest wall usually are separated from it by at least a thin tissue plane through which it is safe to dissect. Determining Tumor Resectability High-grade tumors arising from the shoulder girdle region often are large and encroach on the neurovascular bundle. Tumors that encase or invade the brachial plexus are considered unresectable. In many cases, it is difficult to determine, both clinically and radiologically, which tumors involve or encase the neurovascular structures directly as opposed to merely displacing these structures. Although most tumors that displace the neurovascular structures are resectable, some are unresectable, and it can be difficult to determine clinically which are in this category. We have found the clinical triad of intractable pain, motor deficit, and a venogram showing obliteration of the axillary vein to be very reliable in predicting brachial plexus invasion. No single imaging study is available that accurately visualizes the brachial plexus. Magnetic resonance imaging (MRI) and computed tomography (CT) scans typically show a large tumor juxtaposed to the neurovascular bundle (FIG 5). P.88

FIG 5 • Imaging studies of the shoulder girdle and axillary space demonstrating bony and soft tissue findings. A. CT scan showing a tumor arising from the glenoid and involving the glenohumeral joint. CT scans are the best modality for observing bony detail. B. Coronal MRI scan showing direct tumor extension. C,D. A large soft tissue axillary tumor (arrows) protruding anteriorly through the pectoralis major and the skin. This is a highgrade fungating soft tissue sarcoma. MRI is the best scan for evaluation of soft tissue masses in relation to other soft tissue structures. E. MRI scan of the axillary space (coronal view) showing a secondary skipped lesion along the axillary vein, coming from a high-grade soft tissue sarcoma lower in the axilla. Metastatic lesions of the axilla and lymph nodes are a common source of large axillary masses and are best evaluated by MRI scans. F. Angiography and embolization of metastatic renal cell carcinoma (hypernephroma) to the distal clavicle. Following embolization, there is no evidence of a tumor blush. Embolization often is performed for large high-grade soft tissue sarcomas prior to a resection. (continued) P.89

FIG 5 • (continued) G. On this axillary venogram, the axillary vein is occluded by thrombosis, and there is a small backward filling from the innominate vein. This is the most pathognomonic finding of brachial plexus involvement seen during the time of surgery. Brachial plexus involvement often correlates with the clinical findings of neurologic deficits, numbness, or muscle weakness of the affected extremity. H. Three-dimensional angiogram demonstrating the arteries of the shoulder girdle. Angiograms are particularly useful in determining patency of the vessels and local anatomy or anatomic anomalies within the surgical field as well as angiogenesis to particularly vascular tumors. Venography, however, is extremely accurate in predicting brachial plexus invasion. The axillary vein, axillary artery, and brachial plexus travel in intimate association within a single fascial sheath, the axillary sheath. The major nerves and cords travel along the periphery of the sheath; therefore only complete obliteration—not just compression—of the brachial or axillary vein denotes direct tumor extension in and around the nerves and also indicates secondary involvement of the venous wall. This progression also explains the clinical triad of pain, motor loss, and venous obstruction. Tumors that invade or encase the brachial plexus obliterate the axillary vein because of that vein's thin walls and low intraluminal pressure. In these instances, arteriography demonstrates displacement of the axillary artery; however, the axillary artery remains patent because of its thick walls and high intraluminal pressures. The final decision regarding the need for a forequarter amputation should be reserved until surgical exploration of the brachial plexus has been performed.

Prosthetic Reconstruction When endoprosthetic reconstruction was developed in the 1940s, attention initially was focused on reconstruction of skeletal defects of the lower extremity. Use of the technique was broadened gradually to include defects of the upper extremity and shoulder girdle. The Modular Replacement System (MRS) shoulder prosthesis has undergone several design changes and improvements since that time. The current components for proximal humerus and scapular replacement are shown in Chapters 9 and 10, respectively. The MRS is used in conjunction with both intra- and extra-articular resections, and results are highly predictable and successful. Reported rates of fracture, infection, nonunion, reoperation, and tumor recurrence are lower, and length of immobilization is shorter with extremity endoprosthetic reconstruction than with allograft, composite reconstruction, or arthrodesis.

Survival of the MRS proximal humeral prosthesis is reported to be 95% to 100% at 10 years.

TECHNIQUES ▪ Skeletal Reconstruction following Humerus and Scapular Resections Special prosthetic replacements are recommended for skeletal reconstruction following proximal humerus and total scapular resections, although the utilitarian approach may be used with any method of reconstruction (TECH FIG 1). Soft tissue reconstruction is accomplished using a dual suspension technique that employs static and dynamic methods of prosthetic stabilization and soft tissue and motor reconstruction. Static methods of stabilization include the use of heavy nonabsorbable sutures, Dacron tapes, or GoreTex grafts, depending on the site of tumor resection and the prosthesis that is being used. This method offers secure fixation and stabilization of the prosthesis until the soft tissues heal and scar to each other. Dynamic methods of stabilization and reconstruction include multiple muscle rotation flaps and muscle transfers that eventually heal, scar to each other and the prosthesis, and provide the necessary motor units for a functional extremity. Soft tissue reconstruction follows skeletal reconstruction and static stabilization. The short head of the biceps is attached with a tenodesis proximally to the coracoid (intra-articular proximal humerus reconstruction), the clavicle (extra-articular proximal humerus reconstruction), or pectoralis major (total scapula reconstruction). The pectoralis minor also is tenodesed back to its origin, when possible, or to the scapula to protect the neurovascular structures. The pectoralis major is repaired to its humeral insertion or, in P.90 P.91 cases requiring extra-articular proximal humerus reconstruction, transferred to cover the prosthesis with soft tissues. The latissimus dorsi may be transferred laterally to function as an external rotator following extra-articular proximal humerus resection.

TECH FIG 1 • A. Utilitarian incision. This incision has been developed based on the extensive experience of surgeons performing resections around the shoulder girdle. It consists of three components. Dashed line A indicates the anterior approach, an extended deltopectoral incision coming from the midclavicle through the deltopectoral interval and distally over the medial aspect of the arm, curving in a posterior direction. Dashed line B is a posterior incision that is somewhat curved in nature to allow development of a large posterior fasciocutaneous flap for exposure of the entire scapula and rhomboid region. Dashed line C is an incision that connects A and B through the axillary folds. This permits resection of large axillary tumors or performance of forequarter amputations. B. The initial steps of the anterior approach of the utilitarian shoulder girdle incision. The key to this approach is the release of the pectoralis major from its insertion on the humerus (1 to 2 cm away). With the pectoralis major now reflected onto the chest wall, the entire axillary space can be exposed. This is termed the first layer of musculature of the axillary space. The second muscular layer of the axillary space is then visualized. With the pectoralis major layer retracted, the axillary space is completely covered by fascia, similar to the peritoneum. This covers two muscles, the short head of the biceps and the pectoralis minor, which attach to the coracoid process, which must be released. With these two muscles released, the axillary space and infraclavicular

component of the brachial plexus (ie, the axillary vein and artery through its entire length) can be explored completely. If necessary, a portion of the clavicle can be resected to expose the subclavian artery and vein. (continued)

TECH FIG 1 • (continued) C. Intraoperative photograph demonstrating the axillary exposure following the utilitarian shoulder girdle incision. Once the pectoralis major and deltoid muscles have been retracted, the infraclavicular component of the axillary vessels can be visualized. The biopsy tract will be removed in situ to prevent contamination of the compartment. (Courtesy of Martin M. Malawer.) In total scapula reconstruction, the periscapular muscles are tenodesed to the prosthesis with heavy nonabsorbable sutures or tapes in a manner that covers the entire prosthesis with muscle. Following isolated axillary tumor resection, the distal (humeral) transected edge of the latissimus dorsi muscle is rotated into the defect and sutured to the superficial surface of the subscapularis muscle to fill the dead space. Large-bore closed suction drains are routinely placed prior to skin closure.

PEARLS AND PITFALLS Preoperative evaluation

▪ Physical examination and radiologic imaging modalities are useful for predicting whether a tumor is resectable. The scapula and proximal humerus should move freely from the chest wall. Chronic swelling in the distal extremity, intractable pain, motor loss, and a venogram that demonstrates obliteration of the axillary vein strongly suggest that the tumor is

unresectable. The final determination regarding the need for a forequarter amputation is made intraoperatively, after anterior exposure and exploration of the brachial plexus and neurovascular structures. Neurovascular exploration and mobilization

▪ The key to a safe and adequate resection of all types of neoplasms around the shoulder girdle lies in adequate visualization, exposure, dissection, mobilization, and preservation of all vital neurovascular structures. Full exposure is facilitated by releasing the pectoralis major muscle from its humoral insertion and the strap muscle from the coracoid process.

Type of resection

▪ High-grade sarcomas that arise from the proximal humerus or scapula are likely to contaminate or cross the glenohumeral joint, either grossly or microscopically. An extra-articular type of resection is used for most high-grade sarcomas arising from the scapula or proximal humerus. Clavicular tumors, although less common, require a slightly different surgical approach (FIG 6).

Soft tissue reconstruction

▪ Soft tissue reconstruction is just as important as skeletal reconstruction during limb-sparing surgery if a functional extremity is to be provided. Static and dynamic methods of soft tissue reconstruction and stabilization are used. Static methods rely on heavy nonabsorbable sutures, Dacron tapes, and Gore-Tex grafts. Dynamic methods rely on multiple muscle transfers and rotational muscle flaps.

P.92

FIG 6 • Example of a safe exposure of a clavicular tumor. The tumor arising from the distal clavicle is a solitary metastasis. The trapezius has been mobilized. The pectoralis major has been detached from the clavicle, and the deltoid has been detached from the acromion.

FIG 7 • A. Results of 134 shoulder girdle resections classified as type of resection versus function as measured by the Musculoskeletal Tumor Society (MSTS) scale. B. Composite photograph demonstrating head, body, and stem components for humeral resections. C. Proximal humerus modular replacement system options from Stryker Orthopaedics. D. Proximal humerus and scapular prosthesis system. E. Plain radiograph following reconstruction using a constrained total scapula replacement.

OUTCOMES The types of tumors, anatomic locations, and types of shoulder girdle resections performed in 134 patients treated at the authors' institutions from 1980 to 1998 are shown in FIG 7A. Experience in these patients with endoprosthetic reconstruction of the proximal humerus and scapula demonstrates that this is a reliable and durable technique of reconstruction (FIG 7B-E). In the same publication, the function after the surgery was estimated to be good to excellent in 101 patients (75.4%), moderate in 23 patients (17.1%), and poor in 10 patients (7.5%). Overall, patients with intra-articular resection and reconstruction have better functional outcomes than patients who underwent extra-articular resections and reconstruction. Survival rates based on Kaplan-Meier analysis demonstrate a 9-year survival rate of 98% to 99% for proximal humeral replacements. No mechanical failures or dislocations occurred. Other groups have reported a significant incidence of dislocation following endoprosthetic reconstruction of the shoulder girdle, but this has not been our experience, attributable to the soft tissue reconstruction. The results shown in FIG 7A reflect the use of “dual suspension” (ie, both static and dynamic) or capsular reconstruction techniques and meticulous attention to soft tissue reconstruction. P.93

FIG 8 • Clinical photograph of a patient 2 years postoperatively demonstrating the anterior incision scar as well as a custom right shoulder orthosis. She is able to wear regular undergarments with the use of the orthosis and has an approximately anatomic contour to the shoulder. Normal hand dexterity and complete range of motion of the elbow is expected after limb-sparing surgery of the shoulder girdle. Good cosmetic appearance is gained through the use of a custom shoulder orthosis (FIG 8).

COMPLICATIONS The utilitarian shoulder approach ensures safe mobilization of major neurovascular structures. Optimal surgical margins are facilitated, and unnecessary complications and local recurrences are minimized. Nerve complications after shoulder girdle resection can occur rarely but are transient. Typically, they occur as a result of nerve traction during surgery or secondary to the immediate postoperative swelling. Normally, 6 months after the surgery, all nerve palsies were resolved. Wound infection is described in approximately 2.5% of the patients who were treated with limb-sparing surgery.

REFERENCES 1. Baumann PK. Resection of the upper extremity in the region of the shoulder joint. Khirurgh Arkh

Velyaminova 1914;30:145. 2. Bickels J, Wittig JC, Kollander Y, et al. Limb-sparing resection of the shoulder girdle. J Am Coll Surg 2002;194(4):422-435. 3. Dahlin DC. Bone Tumors: General Aspects and Data on 6,221 Cases, ed 3. Springfield, IL: Charles C Thomas, 1978. 4. Francis KC, Worcester JN. Radical resection for tumors of the shoulder with preservation of a functional extremity. J Bone Joint Surg Am 1962;44A:1423-1430. 5. Guerra A, Capanna R, Biagini R, et al. Extra-articular resection of the shoulder (Tikhoff-Linberg). Ital J Orthop Traumatol 1985; 11:151-157. 6. Henshaw RM, Jones V, Malawer MM. Endoprosthetic replacement with the modular replacement system: survival analysis of the first 100 implants with a minimum 2-year follow-up. Presented at the Combined Meeting of the American and European Musculoskeletal Tumor Societies, May 6-10, 1998, Washington, DC. 7. Linberg BE. Interscapulo-thoracic resection for malignant tumors of the shoulder girdle region. J Bone Joint Surg 1928;10:344. 8. Liston R. Ossified aneurysmal tumor of the subscapular artery. Eduil Med J 1820;16:66-70. 9. Malawer MM. Tumors of the shoulder girdle: technique of resection and description of a surgical classification. Orthop Clin N Am 1991;22:7-35. 10. Malawer MM, Link M, Donaldson S. Sarcomas of bone. In: DeVita VT, Hellman S, Rosenberg SA, eds. Cancer: Principles and Practice of Oncology, ed 3. Philadelphia: JB Lippincott, 1984:1418-1468. 11. Malawer MM, Sugarbaker PH, Lambert MH, et al. The Tikhoff-Linberg procedure and its modifications. In: Sugarbaker PH, ed. Atlas of Sarcoma Surgery. Philadelphia: JB Lippincott, 1984. 12. Marcove RC. Neoplasms of the shoulder girdle. Orthop Clin N Am 1975;6:541-552. 13. Marcove RC, Lewis MM, Huvos AG. En-bloc upper humeral interscapulothoracic resection. The TikhoffLinberg procedure. Clin Orthop 1977;124:219-228. 14. Mussey RD. Removal by dissection of the entire shoulder blade and collar bone. Am J Med Sci 1837;21:390-394. 15. Pack GT, Baldwin JC. The Tikhoff-Linberg resection of the shoulder girdle. Case report. Surgery 1955;38:755-757. 16. Pack GT, Crampton RS. The Tikhoff-Linberg resection of the shoulder girdle. Clin Orthop 1961;19:148161.

17. Papioannou AN, Francis KC. Scapulectomy for the treatment of primary malignant tumors of the scapula. Clin Orthop 1965;41:125. 18. Rosenberg SA, Suit FD, Baker LH. Sarcomas of soft tissue. In: Devita VT, Hellman S, Rosenberg SA, eds. Cancer: Principles and Practice of Oncology, ed 2. Philadelphia: JB Lippincott; 1985:1243-1293. 19. Samilson RL, Morris JM, Thompson RW. Tumors of the scapula: a review of the literature and an analysis of 31 cases. Clin Orthop 1968;58:105-115. 20. Syme J. Excision of the Scapula. Edinburgh: Edmonston and Douglas, 1864. 21. Wittig JC, Bickels J, Wodajo F, et al. Utilitarian shoulder approach for malignant tumor resection. Orthopedics 2002;5:479-484.

Chapter 9 Total Scapular Resections with Endoprosthetic Reconstruction Martin M. Malawer Kristen Kellar-Graney James C. Wittig

BACKGROUND Tumors arising from the scapula may become very large before diagnosis. Initially, they are often contained by muscle, which protects other tissues within the shoulder girdle. Patients with scapular tumors often present with pain, a mass, or both. Chondrosarcomas are the most common primary malignancy of the scapula in adults; in children, the most common primary malignancy of the scapula is Ewing sarcoma. Soft tissue tumors may involve the periscapular musculature and secondarily invade the scapula. Indications for limb-sparing surgeries of the shoulder girdle include most high-grade bone sarcomas and some soft tissue sarcomas, depending on the tumor extension. Scapular tumors, such as tumors of the proximal humerus, require careful preoperative staging, appropriate imaging studies, and a thorough knowledge of local anatomy. Selection of patients whose tumor does not involve the neurovascular bundle, thoracic outlet, or adjacent chest wall is required. It is rare when forequarter amputation is indicated. It is mainly reserved for patients with large, fungating tumors or infected tumors; those in whom limb-sparing resection has failed; and those with tumors invading the major nerves and vessels or the chest wall. Before 1970, most patients with high-grade sarcomas arising from the scapula were treated with a forequarter amputation.2,3,4,7 The first limb-sparing surgeries for high-grade sarcomas arising from the shoulder girdle were reported by Marcove et al6 in 1977. They reported that the Tikhoff-Linberg resection (FIG 1A) achieved local tumor control and survival similar to that achieved with a forequarter amputation. Most importantly, a functional hand and elbow were preserved. Limb-sparing surgery for patients with high-grade sarcomas in this location soon became standard treatment. Today, the majority of malignancies arising from or involving the scapula can be treated safely with limbsparing surgery in lieu of a forequarter amputation. Shoulder motion and strength are nearly normal after a partial scapular resection (type II). However, there is significant loss of shoulder motion, predominantly shoulder abduction, after a total scapular resection (type III), alone or in conjunction with an extra-articular resection of the shoulder joint and proximal humerus (types IV and VI).5 Suspension of the proximal humerus and meticulous soft tissue reconstruction are the keys to providing shoulder stability and a functional extremity. If significant periscapular muscles remain after tumor resection (especially the trapezius and deltoid muscles), a total shoulder-scapula prosthesis may be the optimal reconstructive option (FIG 1B-F).

ANATOMY The local anatomy of a scapular tumor determines the type of scapular resection and subsequent reconstruction. Because these tumors become quite large before diagnosis, the surgeon should thoroughly inspect the chest wall, axillary vessels, proximal humerus and rotator cuff, and periscapular tissue to ensure

that an appropriate procedure is planned. Sarcomas involving the glenoid, scapular neck, or supraspinatus musculature usually involve the glenohumeral joint and adjacent capsule. Therefore, an extra-articular resection through a combined anterior and posterior approach should be performed for tumors in this location. Large sarcomas of the scapula with soft tissue extension can involve the axillary vessels and the brachial plexus. Likewise, lymph nodes in the surrounding region should be evaluated to determine resectability. Suprascapular tumors are difficult to palpate on physical examination. Even sophisticated imaging modalities may incorrectly estimate the extent of these tumors. Tumors in this location can extend into the anterior and posterior triangles of the neck, making resection impossible except in the cases of palliation.

Key Anatomic Structures of the Scapular Region Neurovascular Bundle The subclavian artery and vein join the cords of the brachial plexus as they pass underneath the clavicle. Beyond this point, the nerves and vessels are surrounded by a fibrous sheath and can be considered one structure (ie, the neurovascular bundle). The suprascapular, dorsal scapular, and circumflex scapular vessels form an extensive vascular network around the posterior scapula. Each of these vessels must be ligated and transected to resect the scapula. Axillary Vessels The axillary blood vessels are a continuation of the subclavian vessels as they pass underneath the middle third of the clavicle and are called the brachial vessels once they pass the inferior border of the latissimus dorsi muscle. The axillary vessels pass medial and inferior to the coracoid process en route to the proximal humerus. They are surrounded by the brachial plexus throughout their entire course. The artery yields several branches during its course. The first branch arises as the artery passes over the first rib and is called the supreme thoracic artery. While the artery is deep to the pectoralis minor muscle, the thoracoacromial artery arises followed by the lateral thoracic artery and then the P.95 subscapular artery. The thoracoacromial artery gives rise to four branches, one of which supplies the area around the acromion.

FIG 1 • A. Plain radiograph showing the traditional resection of the shoulder girdle after a Tikhoff-Linberg resection. The Tikhoff-Linberg resection includes the entire scapula and the proximal humerus en bloc extraarticularly. B. The original scapular prosthesis designed by Howmedica, Inc. (Rutherford, NJ, 1991). This prosthesis is quite solid and large and contains fenestrated holes for reattachment. The humeral head articulated with a polyethylene glenoid but was held in place only by muscle transfers and/or the use of a Gore-Tex sleeve. C. The second generation of the scapula that was used in the late 1990s. This prosthesis offered fenestrations within the body of the scapula to allow the adjacent muscles to tenodese to give the recreated shoulder a new and more stable attachment. The proximal humeral component could, at this point, be mated with the Modular Replacement System for resections of the proximal humerus. This greatly increased the surgeon's ability to reconstruct the proximal humerus and shoulder girdle. D. Plain radiograph showing a 13-year follow-up of this prosthesis in a patient with hemangiosarcoma of the scapula. E. The thirdgeneration scapular prosthesis that was developed by Howmedica, Inc. (now Stryker Orthopaedics, Mahwah, NJ). This prosthesis is the first articulating scapular prosthesis. The bipolar proximal humeral head fits into the glenoid with a polyethylene retaining rim. F. Gross specimen after an extended Tikhoff-Linberg resection (type IV) that included the entire scapula, an extra-articular resection of the glenohumeral joint, and a portion of the proximal humerus with all of the muscles attached. The subscapular artery divides into the thoracodorsal artery and the circumflex scapular artery that wraps around the lateral border of the scapula and tethers the axillary vessels to the scapula. The anterior and posterior humeral circumflex arteries are the final branches of the axillary artery. They arise at the level of the inferior border of the subscapularis muscle and wrap circumferentially around the humeral neck. The axillary nerve runs with the posterior humeral circumflex vessels. The humeral circumflex vessels tether the neurovascular structures down to the proximal humerus and hence to any neoplasm that arises from this site. Early ligation of the circumflex vessels is a key maneuver in resection of scapular sarcomas because it permits mobilization of the axillary and brachial vessels and brachial plexus away from the tumor mass. Likewise, ligation of the subscapular artery, or circumflex scapular artery if possible, allows mobilization of the neurovascular structures away from the scapula. Occasionally, there is anatomic variability in the location of the branches of the axillary artery that leads to difficulty in identification and exploration if not previously recognized. A preoperative angiogram can help determine vascular displacement by neoplasm and anatomic variability.

Suprascapular Nerve The suprascapular nerve arises from the superior trunk of the brachial plexus as it passes over the first rib. It travels posterior through the scapular notch deep to the transverse scapular ligament and supplies the supraspinatus and infraspinatus muscles. Musculocutaneous and Axillary Nerves These two nerves are often in close proximity to or in contact with tumors around the scapula. The musculocutaneous nerve is the first nerve to arise from the brachial plexus. It arises from the lateral cord just distal to the coracoid process, passes through the coracobrachialis, and runs between the brachialis and biceps. It should be preserved, if possible, to maintain elbow flexion. The path of this nerve may vary extensively. It usually passes 2 to 7 cm inferior to the coracoid process. Tumors that arise from the scapula often displace this nerve anteriorly so that it occupies a position only 1 to 2 mm deep to the fascia. Care should be taken when opening the fascia overlying this nerve in the interval between the coracobrachialis and pectoralis minor muscles. The nerve should be identified and P.96 protected before releasing any muscles from the coracoid process because it can be easily injured during the resection. The axillary nerve arises from the posterior cord of the brachial plexus and courses, along with the posterior humeral circum-flex vessels, inferior to the distal border of the subscapularis. It then passes between the teres major and minor muscles to innervate the deltoid muscle posteriorly. Tumors of the scapula usually displace and stretch the axillary nerve. The nerve is usually protected from the tumor by the subscapularis muscle. Radial Nerve The radial nerve arises from the posterior cord of the brachial plexus. It passes anterior to the latissimus dorsi —teres major insertion on the humerus. Just distal to the latissimus dorsi insertion, the nerve courses into the posterior aspect of the arm, just lateral to the long head of the triceps, to run in the spiral groove between the medial and lateral heads of the triceps. The radial nerve must be isolated and protected before resection. Upper and Lower Subscapular Nerves and Thoracodorsal Nerve The upper and lower subscapular nerves and the thoracodorsal nerve arise from the posterior cord of the brachial plexus near where the subscapular artery and humeral circumflex vessels arise from the axillary artery. The upper and lower subscapular nerves descend and enter directly into the substance of the subscapularis muscle. These nerves are routinely ligated during a scapulectomy. The thoracodorsal nerve passes with the thoracodorsal artery distally, directly anterior to the subscapularis muscle, to supply the latissimus dorsi muscle. The thoracodorsal nerve can usually be spared during most scapular resections.

FIG 2 • Indications for scapulectomy. A. MRI (T2-weighted signal) shows an extensive tumor arising from the coracoid and involving the scapula and the glenohumeral joint. B. Bone scan of a large giant cell tumor of the scapula with complete scapular involvement. This study revealed that there was minimal bone remaining. C. An extremely large periscapular soft tissue sarcoma arising adjacent to the scapula and scapular musculature and also involving the musculature of the proximal humerus. The initial procedures performed by Tikhoff and Linberg (reported in 1928) were resections for periscapular soft tissue sarcomas and not primary or metastatic bony sarcomas. D. Angiography of an osteosarcoma of the scapula before induction chemotherapy. There is marked vascularity and displacement of the axillary artery as well as the circumflex vessels.

INDICATIONS Limb-sparing surgery is indicated for most sarcomas of the scapula (FIG 2). Soft tissue sarcomas that extend into the scapula can usually be resected with a limb-sparing surgery. Metastatic carcinoma, myeloma, or lymphoma that has completely destroyed the scapula and has either failed to respond to radiation therapy or chemotherapy or may be treated by limb-sparing surgery Certain key muscles, along with the axillary nerve, must be capable of being preserved if the shoulder girdle is to be reconstructed with a total scapula prosthesis: the trapezius, deltoid, rhomboids, serratus anterior, and latissimus dorsi. These muscles provide the soft tissue coverage necessary to suspend the prosthesis and allow it to function. If these muscles cannot be preserved, the humerus is suspended from the clavicle. Static and dynamic methods of soft tissue reconstruction are used to stabilize the humerus. This involves the use of 3-mm Dacron tapes, heavy nonabsorbable sutures, and multiple muscle rotations and transfers.

Contraindications for Limb-Sparing Surgery for Scapular Tumors Tumors that extend into the axilla with vessel involvement or invasion of the brachial plexus or those that have extensive involvement with the chest wall typically cannot be safely resected using limb-sparing techniques. Tumor invasion or encasement of the brachial plexus and axillary vessel requires amputation. Involvement of a single nerve is not an absolute contraindication to limb salvage.

Extensive chest wall involvement P.97 Relative contraindications include the following: An inappropriately placed biopsy that has resulted in extensive contamination of the surrounding soft tissues An active or previous infection A recurrent sarcoma that cannot be adequately resected without performing a forequarter amputation Presence of a displaced pathologic fracture secondary to a sarcoma, which does not heal after preoperative chemotherapy

IMAGING AND OTHER STAGING STUDIES Plain Radiography Plain radiography is often the first imaging modality in the diagnosis of tumors of the scapula. This will reveal most bony and some soft tissue involvement. The scapula can sometimes be difficult to visualize on plain radiographs because it is often obscured by the rib cage. Mineralization shown on plain radiographs may help categorize a bone sarcoma as either an osteosarcoma or chondrosarcoma.

Computed Tomography and Magnetic Resonance Imaging Computed tomography (CT) and magnetic resonance imaging (MRI) are the most valuable means of determining the size and extent of extraosseous disease and its relationship to the axillary vessels, glenohumeral joint, and chest wall (see FIG 2D). CT is extremely important for evaluating the rib cage. Subtle erosion of the rib cage by an adjacent scapula tumor is best visualized on a CT scan. It is the best test for detecting subtle mineralization within tumors as well as for detecting subtle areas of scapular involvement by adjacent soft tissue sarcomas. Contrastenhanced CT is particularly helpful for determining the proximity of the tumor to the axillary and brachial vessels and brachial plexus. MRI is most accurate for determining intraosseous and extraosseous tumor extent as well as for detecting skip metastases. An appreciation of the intraosseous extent is necessary for determining the length of bone resection. The proximal humerus is usually transected approximately 2 to 3 cm distal to the intramedullary extent of the neoplasm as visualized on a T1-weighted MRI image. MRI is extremely useful to evaluate the proximity of the extraosseous tumor component to the axillary and brachial vessels and brachial plexus.

FIG 3 • Proper biopsy technique for tumors in the shoulder compartment. (Reprinted with permission from Bickels J, Jelinek JS, Shmookler BM. Biopsy of musculoskeletal tumors. Current concepts. Clin Orthop Relat Res 1999;368: 212-219.)

Bone Scan A bone scan is helpful in identifying bony involvement of the proximal humerus or ribs in the regional area, looking for local extension and metastatic disease in the entire bony skeleton. Because the scapula is very thin throughout the major part of its body, the bone scan may not be as accurate as when evaluating the long bones for tumor extent. The bone scan should be correlated with an MRI.

Angiography and Other Studies Angiography can determine vascular involvement and reveal any anomalies of the vascular anatomy. Displacement of the axillary vessels is indicative of anterior tumor extension into the axilla. Axillary venography is performed if there is any clinical suspicion of brachial plexus involvement, such as nerve pain or distal edema, the hallmarks of invasion of the brachial plexus. Occluded axillary veins seen on venography correlate with brachial plexus infiltration.

Biopsy We recommend fine needle or core biopsies be performed under CT or fluoroscopic guidance in an attempt to protect the neurovascular bundle. One puncture site is required. The needle is then reintroduced through that site at various angles to obtain cores from several different regions of the tumor. The biopsy site should be placed along the intended incision site of the resection (FIG 3). A posterior needle biopsy is recommended for tumors arising within the body of the scapula; the anterior approach should be avoided to minimize the risk of soft tissue contamination by tumor.

Scapular Biopsies Biopsies of the scapular body are more difficult to perform than biopsies of the proximal humerus. They should be P.98 performed along the lateral or axillary aspect of the scapula and not along the vertebral (medial) border or directly posterior through any potential skin flaps. The biopsy site should be along the intended incision site of the resection. A posterior needle biopsy is recommended for tumors arising within the body of the scapula; the anterior approach should be avoided. Biopsies of tumors in the lateral aspect of the scapula or glenoid region should be performed along the lateral or axillary aspect of the posterior scapula directly through the infraspinatus or teres minor muscles.

SURGICAL MANAGEMENT Preoperative Planning All imaging studies, particularly CT, MRI, and angiography or venography, are reviewed before surgery to determine surgical resection type and feasibility. The patient is examined for distal edema and motor loss, which may indicate brachial plexus infiltration, an unresectable situation. The scapula should also move free from the chest wall, indicating that gross chest wall invasion is unlikely. Distal pulses are checked before surgery to ensure adequacy; fainter distal pulses are correlated with arterial invasion. The MRI and CT are reviewed to determine the proximity of the neoplasm to the brachial plexus and axillary vessels as well as to the chest wall. The soft tissue extent of the lesion is determined and a judgment is made about preservation of important periscapular muscles, essential for prosthetic reconstruction of the scapula. The arteriogram and venogram are also reviewed. Final determination of resectability and the use of a total scapula prosthesis, if the tumor is deemed resectable, is made intraoperatively.

Positioning The patient is placed in a lateral or semilateral position that permits access to the posterior aspect of the shoulder girdle all the way to the spinous processes. The affected extremity is prepared and draped free (FIG 4A).

FIG 4 • A. Patient positioning. B. Utilitarian incision of the shoulder girdle. Occasionally, a scapular resection can be performed completely through the posterior incision; however, if there is a large anterior tumor extension with displacement of the axillary vessels or an extraosseous soft tissue component, it is much safer to proceed with an anterior approach similar to the proximal humeral resections.

Approach Most tumors of the scapula or periscapular soft tissues that require a total scapular resection are resected through a combined anterior and posterior approach. Most of these tumors have a large anterior soft tissue component that is juxtaposed to or that displaces the axillary vessels and brachial plexus. The anterior approach is crucial in these instances to explore and mobilize these structures away from the neoplasm so that a safe and adequate resection can be performed. The procedure uses both anterior extended deltopectoral incision and posterior incision of the utilitarian shoulder girdle incision (incision A and B in FIG 4B, respectively). Occasionally, a total scapular resection can be performed solely through a posterior approach for neoplasms that do not have an anterior soft tissue component. The surgeon must have a thorough knowledge of the course of axillary vessels, brachial plexus, and all of its branches to perform this procedure safely entirely through a posterior approach. If there are any uncertainties, then the procedure is most safely performed through a combined anterior and posterior approach. The axillary vessels and plexus are explored and mobilized anteriorly. This requires the pectoralis major to be detached and reflected for adequate exposure. The posterior incision permits the release of all muscles attaching to the scapula. The glenohumeral joint is removed extra-articularly. The osteotomy is performed below the level of the joint capsule. A scapular prosthesis is used if sufficient musculature remains; specifically, the deltoid, trapezius, rhomboids, and latissimus dorsi muscles. If there is not sufficient musculature after the resection, the remaining humerus is supported from the clavicle with Dacron tape (static suspension), and the conjoin tendon (dynamic suspension) and a pectoralis major rotational flap is also performed.

P.99

TECHNIQUES ▪ Extra-articular Total Scapula and Humeral Head Resection (Type IV): The Tikhoff-Linberg Procedure This procedure is an extra-articular en bloc resection of the scapula, glenohumeral joint and humeral head, and distal clavicle. A utilitarian anteroposterior approach is used. A large posterior fasciocutaneous flap is developed. The rhomboids and trapezius muscles are released from the vertebral border of the scapula, and the latissimus dorsi muscle is mobilized but not transected. If the tumor does not involve the deltoid or the trapezius, the muscles are preserved and are reflected off the scapular spine and acromion. The classic Tikhoff-Linberg resection does not preserve the deltoid or trapezius muscles. An osteotomy below the humeral head (ie, a scapulectomy and extra-articular resection of the glenohumeral joint in conjunction with the scapula) is performed. Prosthetic reconstruction: If there are significant remaining muscles after a type IV shoulder girdle resection, then a scapula prosthesis is used9 (TECH FIG 1A).

TECH FIG 1 • A. Scapula prosthesis in place with a proximal humeral prosthesis seated. The proximal humeral prosthesis is cemented in place before suturing the scapula to the chest wall. B-D. Technique of Gore-Tex capsule reconstruction. Reconstruction of an artificial capsule is essential for appropriate function and stability. Even though the third-generation scapular prosthesis offers a “snap-fit,” it can dislocate due to the continuous traction forces caused by the weight of the arm. Muscle reconstruction is

completed by rotating the latissimus dorsi over to the rhomboids and the trapezius to the deltoid. All of these muscles are then tenodesed to themselves. The scapula prosthesis is fenestrated to permit the muscles to tenodese to themselves. It has holes drilled along the axillary and vertebral borders for fixation with Dacron tapes. The scapula prosthesis is sutured first to the rhomboid muscles with Dacron tape, and then the latissimus dorsi is rotated over the body of the scapula prosthesis and sutured along the vertebral border. The humeral component is then inserted into the osteotomized proximal humerus. A Gore-Tex graft is used to reconstruct the capsular mechanism (TECH FIG 1B). The Gore-Tex is sutured to the proximal humerus prosthesis and the glenoid neck on the scapula prosthesis with 3-mm Dacron tape (TECH FIG 1C,D). The muscle closure consists of tenodesis of the deltoid to the trapezius and the latissimus over the rhomboids and to the serratus anterior muscles. The scapula prosthesis fits between the serratus anterior and the latissimus dorsi and rhomboid muscles. The deltoid and trapezius muscles have been preserved and are tenodesed together. The latissimus dorsi is rotated up to the lower border of the deltoid and to the rhomboid muscles. The latissimus is sutured to the holes in the axillary border of the scapula prosthesis and the adjacent musculature using Dacron tape and Ethibond sutures, respectively. P.100

▪ Intra-articular Scapular Resection (Type III) This resection is an intra-articular total scapulectomy. It is most commonly performed for soft tissue sarcomas that secondarily invade the scapula. A posterior and anterior incision is used, respectively. The posterior deltoid is released from the acromion and scapular spine. The trapezius muscle is released and retracted. The rhomboid muscles are released starting at the inferior angle of the scapula. The tip is then elevated and the scapula is retracted away from the chest wall as muscle release continues medially, laterally, and then superiorly to permit visualization of the axilla and chest wall. The inferior tip of the scapula is rotated, and traction is applied with the arm abducted. The axillary contents are gently retracted. The neurovascular structures are approached from the back, unless the tumor has an anterior extraosseous component. The neurovascular structures are visualized as the scapula is retracted away from the chest wall. The infraspinatus and supraspinatus muscles are transected and the joint is entered. The anterior capsule and the subscapularis tendon are transected. The long head of the biceps is identified, tagged with suture, and divided.

TECH FIG 2 • A. A scapula prosthesis in place with a proximal humeral prosthesis seated. The proximal humeral prosthesis is cemented in place before suturing the scapula to the chest wall. This allows for correct positioning and retroversion of the humeral component. B. Muscle reconstruction. The acromioclavicular joint is entered and released or the distal portion of the clavicle is resected with the specimen. As the scapula is gently elevated, the short head of the biceps and the coracobrachialis and pectoralis minor muscles are released from the coracoid. The musculocutaneous nerve must be protected as it passes near the coracoid. The dual suspension technique using Dacron tape to suspend the proximal humerus from the clavicle can be used. Dacron tape (3 mm) is used to suspend the remaining humerus from the distal clavicle. The biceps, coracobrachialis, and triceps are reattached through drill holes in the distal clavicle. If the deltoid muscle has been preserved, it is tenodesed anteriorly to the pectoralis major and trapezius muscles to further reconstruct the anterior aspect of the shoulder girdle. If adequate musculature remains, a total scapular prosthesis (see Tikhoff-Linberg techniques) can be used to reconstruct the defect (TECH FIG 2). There are two major pairs of muscles that must be reconstructed: the trapezius muscle to the remaining portion of the deltoid (this is tenodesed over the superior third of the prosthesis and glenohumeral joint) and then the rhomboid muscles to the prosthesis (covered by the transfer of the latissimus dorsi from its origin). This forms a nice pocket for the prosthesis to sit in between the latissimus dorsi and rhomboids and against the serratus anterior and chest wall.

P.101

PEARLS AND PITFALLS Preoperative evaluation

▪ MRI and CT are important for evaluating the proximity of the tumor to the neurovascular structures, chest wall invasion, and involvement of other key muscles around the scapula.

Resection

▪ Most total scapular resections (extra-articular and intra-articular) are performed through an anterior and posterior approach. This is the safest method when a large anterior soft tissue component exists.

Exposure of neurovascular structures

▪ The axillary vessels and brachial plexus are best exposed through an anterior approach (extended deltopectoral incision) that involves releasing the pectoralis major muscle from its humeral insertion and the coracobrachialis muscle and the short head of biceps and pectoralis minor muscle from their coracoid attachments.

Posterior exposure and exploration

▪ During the posterior portion of the resection, it is important to preserve the periscapular muscles, which are crucial for prosthetic reconstruction, if possible. These muscles include the rhomboids, trapezius, deltoid, serratus anterior, and latissimus dorsi muscles. The axillary nerve must also be preserved.

Prosthetic reconstruction

▪ A small scapular component is used if it will facilitate better soft tissue coverage. The humeral component is chosen to allow for up to 2 cm of shortening of the extremity, which also facilitates soft tissue closure. A constrained total scapula is preferred. A Gore-Tex aortic graft is used to reconstruct the glenohumeral joint capsule. The scapula prosthesis is positioned as medial as possible (1-2 cm away from the spine) in a pocket between the rhomboids and serratus anterior muscles. The deltoid and trapezius muscles are retensioned as they are sutured to each other and to the prosthesis. The latissimus provides final coverage of the prosthesis. At the conclusion of the procedure, the entire prosthesis must be thoroughly covered with muscle.

Postoperative care

▪ Placement of temporary epineural catheter within the brachial plexus nerve sheath for pain control ▪ The patient is kept in a brace for 6 weeks with the arm abducted 45-60 degrees and the elbow flexed 45 degrees.

POSTOPERATIVE CARE Epineural catheters are routinely used with a continuous bupivacaine (4 to 8 mL of 0.25% bupivacaine) infusion for 3 to 5 days. A special brace is recommended for 6 weeks postoperatively that will hold the arm in 45 to 60 degrees of abduction and the elbow flexed 45 degrees. Postoperatively, a sling is required for 4 to 6 weeks. In the immediate postoperative period, the patient is instructed on motion exercises for the wrist and hand, and elbow flexion is encouraged within the confines of the sling. Neck motion and shoulder elevation exercises are instituted within 1 to 2 days after surgery. Once the incision has healed and the sutures are removed, at 2 to 4 weeks after surgery, pendulum exercises and gentle shoulder motion (flexion, extension, internal and external rotation) are done with the help of a family member or physical therapist. Elbow flexion, extension, supination, and pronation are also performed. Gentle strengthening is instituted once motion has returned, with the use of active motion and isometric exercises and light weights (2 to 10 pounds). At 12 weeks postoperatively, strengthening is initiated with Thera-Bands and other resistance exercises up to a 10-pound weight limit. Ultimately, the patient is restricted to a 15- to 20-pound weight limit. Long-term weightlifting restrictions of less than 20 pounds are generally recommended.

OUTCOMES Prosthetic reconstruction of the scapula is a very reliable method of reconstruction after an intra-articular or extraarticular resection of the scapula. All patients have a painless, stable shoulder girdle and functional use of the hand and elbow. Rotation below the shoulder is preserved and ranges from −10 degrees of external rotation to T6 for internal rotation.1,8 Internal rotation, adduction, and extension strength are virtually normal. Active forward elevation and abduction (combined glenohumeral and scapulothoracic motion) range from 25 to 45 degrees and are grade 3 to 4 in terms of motor strength. Scapular protraction, retraction, and elevation are restored. These muscles participate in stabilizing the upper extremity when lifting objects. Patients can lift and carry objects up to 20 pounds. Most patients can perform push-ups. Upper extremity strength is better than when the shoulder is left flail or the remaining humerus is suspended from the clavicle. The Musculoskeletal Tumor Society Score for upper extremity function ranges from 24 to 27 out of 30 points (80% to 90%) (FIG 5). Elbow, wrist, and grip strength are normal in all patients. All patients can reach the tops of their heads, opposite shoulder and armpit, and perineal area with their hand. There are no limitations in activities of daily living, including feeding, dressing, and personal hygiene. Lifting ability is normal with the arm at the side of the body. Cosmesis is acceptable. The major limitations have been with recreational activities and other activities that require the arm to be lifted above the shoulder level.

COMPLICATIONS Complications from a prior biopsy with extensive contamination of tissues may make a limb-sparing scapular resection inadvisable; therefore, an appropriately placed and performed biopsy must occur. If the deltoid muscle cannot be preserved, a scapular prosthesis may not be used. Loss of function of activities above the level of the shoulder girdle should be anticipated: The goal of this surgery is to permit good use of the hand and elbow. P.102

FIG 5 • A. Wound closure with good approximation and no tension. The perineural catheter is placed into the brachial plexus sheath before wound closure. This provides excellent postoperative anesthesia with minimal sensory deficit when 0.25% bupivacaine is used. B. Posterior view of a scapular prosthesis 13 years after reconstruction. Quite impressive symmetry has been attained when comparing the operative and contralateral sides. C. Push test, which is designed to test the rhomboids, serratus anterior, and latissimus dorsi. There is minimal winging of the scapula. In addition, the cosmetic effect of retaining the trapezius and the deltoid is impressive and evident. D. Patient performing a push-up. Great strength and stability of the shoulder girdle is seen here. This stability permits the patient to place the hand in three dimensions in space, the anatomic function of the normal shoulder girdle. Hand and elbow function is normal after these resections. It is extremely rare to have to resect any chords of the brachial plexus, which would result in loss of function of the distal portion of the arm. Skin necrosis occurs rarely. Dislocation of the reconstructed scapular mechanism is rare. In less than 5% of patients, glenohumeral dissociation occurs; it can usually be treated conservatively. Traction neurapraxia is also described in very low percentage of the cases, with the majority of those being transient.

REFERENCES 1. Bickels J, Wittig JC, Kollender Y, et al. Limb-sparing resections of the shoulder girdle: a long-term followup study. J Am Coll Surg 2002;194:422-435. 2. De Nancrede CBG. The end results after total excision of the scapula for sarcoma. Ann Surg 1909;50:1. 3. Linberg BE. Interscapulo-thoracic resection for malignant tumors of the shoulder girdle region. J Bone

Joint Surg 1928;10:344. 4. Liston R. Ossified aneurysmal tumor of the subscapular artery. Edinb Med J 1820;16:66-70. 5. Malawer MM. Tumors of the shoulder girdle: technique of resection and description of a surgical classification. Orthop Clin North Am 1991;22:7-35. 6. Marcove RC, Lewis MM, Huvos AG. En bloc upper humeral interscapulothoracic resection. Clin Orthop Relat Res 1977;124:219-228. 7. Syme J. Excision of the Scapula. Edinburgh: Edmonston & Douglas, 1864. 8. Ward B, McGarvey C, Loetz M. Excellent shoulder function is attainable after partial or total scapulectomy. Arch Surg 1990;125:537-542. 9. Wittig JC, Bickels J, Wodajo F, et al. Constrained total scapula reconstruction after resection of a highgrade sarcoma. Clin Orthop Relat Res 2002;397:143-155.

Chapter 10 Proximal Humerus Resection with Endoprosthetic Replacement: Intra-articular and Extra-articular Resections Martin M. Malawer James C. Wittig Kristen Kellar-Graney

BACKGROUND The proximal humerus is a common site for both primary osteosarcomas and chondrosarcomas and is the second most common site of metastatic disease involving long bones. Metastatic tumors occasionally involve the shoulder girdle and often are treated using the same resection and reconstruction techniques (FIG 1A). Limb-sparing resection of the proximal humerus is challenging. Despite their complexity, these resections can be performed in about 95% of patients with high- or low-grade sarcomas. Amputations rarely are required. Endoprosthetic reconstruction is the most common technique for reconstructing large proximal humeral defects. It is used following both intra-articular (type I) and extraarticular (type V) resections. This type of reconstruction is combined with local muscle transfers to create shoulder stability; cover the prosthesis; and provide a functional elbow, wrist, and hand (FIG 1B). The surgical and anatomic considerations of limb-sparing procedures of the proximal humerus and the specific surgical techniques for type I and type V resection and reconstruction are described in this chapter. Total humeral replacement is described briefly. The proximal humerus is one of the most common sites for high-grade malignant bone tumors in the adult, and it is the third most common site for osteosarcoma.2 Tumors in this location tend to have a significant extraosseous component. The proximal humerus also may be involved by metastatic cancer (especially renal cell carcinoma) and secondarily by soft tissue sarcomas, which require a resection similar to that used for primary bone sarcomas with extraosseous extension. About 95% of patients with tumors of the shoulder girdle can be treated with limb-sparing resections. The Tikhoff-Linberg resection and its modifications are limb-sparing surgical options for bone and soft tissue tumors in and around the proximal humerus and shoulder girdle. Portions of the scapula, clavicle, and proximal humerus are resected in conjunction with all muscles inserting onto and originating from the involved bones. Careful preoperative staging and selection of patients whose tumor does not encase the neurovascular bundle or invade the chest wall are required. A classification system for resection of tumors in this location is described in FIG 1B. The most common procedure for high-grade sarcomas of the proximal humerus, type VB, is described. We do not recommend type I resection for high-grade tumors due to the increased risk of local recurrence. Optimal function is achieved with muscle transfers and skeletal reconstruction. A prosthesis is used to maintain length and stabilize the shoulder and distal humerus following resection. A stable shoulder with normal function of the elbow, wrist, and hand should be achieved following most shoulder girdle resections and reconstructions performed using the techniques described.

INDICATIONS Indications for limb-sparing procedures of the proximal humerus and shoulder girdle include high-grade and some lowgrade bone sarcomas as well as some soft tissue sarcomas that secondarily invade bone. Occasionally, solitary metastatic carcinomas to the proximal humerus and multiple metastatic carcinoma to the proximal humerus with no option of stabilization and fixation are best treated by a wide excision (ie, type I resection). The decision to proceed with limb-sparing surgery is based on the location of the tumor and a thorough understanding of its natural history. Recently, we have treated patients with pathologic fractures with induction chemotherapy, immobilization, and limb-sparing surgery if there is a good clinical response and fracture healing.

CONTRAINDICATIONS Absolute contraindications include tumor involvement of the neurovascular bundle or extensive invasion of the adjacent chest wall (FIG 2). Extensive invasion of the muscles around shoulder girdle Relative contraindications include chest wall extension, tumor contamination of the operative site from hematoma following a poorly performed biopsy or pathologic fracture, a previous infection, or lymph node involvement.

UNIQUE ANATOMIC CONSIDERATIONS Resection and reconstruction of the proximal humerus and shoulder girdle is a technically demanding procedure. The local anatomy of the tumor often determines the extent of the operation required. The surgeon should be experienced with all aspects of shoulder girdle anatomy and the unique considerations it may present.

Proximal Humerus Malignant tumors often present with large soft tissue components (stage IIB) underneath the deltoid that extend P.104 P.105 medially and displace the subscapularis and coracobrachialis muscles.3 Pericapsular and rotator cuff involvement occur early and must be evaluated.

FIG 1 • A. Anatomy of the shoulder girdle. B. Surgical classification of shoulder girdle resections. This system was initially proposed by Malawer in 1991. Types I through III are intra-articular resections, whereas types IV through VI are extra-articular. (A: Courtesy of Martin M. Malawer; B: From Malawer MM, Meller I, Dunham WK. A new surgical classification system for shoulder-girdle resections: analysis of 38 patients. Clin Orthop Relat Res 1991;267:A 7:33-44.)

FIG 2 • A. Schematic drawing showing a resectable tumor. The tumor is compressing and displacing the neurovascular bundle; however, there is no invasion or encasement. This situation commonly arises in the treatment of a sarcoma. An angiogram or venogram would show patency of the axillary vessels. B. Schematic drawing showing an unresectable tumor. The tumor is infiltrating the neurovascular structures and obliterating the axillary vein. Venography would show a nonpatent axillary vein, whereas angiography would show a displaced but patent artery. (Courtesy of Martin M. Malawer.)

Glenohumeral Joint The shoulder joint appears to be more prone to intraarticular or pericapsular involvement by high-grade bone sarcomas than are other joints. Four basic mechanisms exist for tumor spread: direct capsular extension, tumor extension along the long head of the biceps tendon, fracture hematoma from a pathologic fracture, and poorly planned biopsy. These mechanisms place patients undergoing intra-articular resections for high-grade sarcomas at greater risk for local recurrence than those undergoing extra-articular resections. Therefore, it often is necessary to http://e-surg.com

perform an extra-articular resection for high-grade bone sarcomas of the proximal humerus or scapula.

Neurovascular Bundle The subclavian artery and vein join the cords of the brachial plexus as they pass underneath the clavicle. Beyond this point, the nerves and vessels can be considered as one structure (ie, the neurovascular bundle). Large tumors involving the upper scapula, clavicle, and proximal humerus may displace the infraclavicular components of the plexus and axillary vessels.

Musculocutaneous and Axillary Nerves The musculocutaneous and axillary nerves often are in close proximity or contact with tumors around the proximal humerus. The musculocutaneous nerve is the first nerve that leaves between the teres major and minor to innervate the deltoid muscle posteriorly. Tumors of the proximal humerus are likely to involve the axillary nerve as it passes adjacent to the inferior aspect of the humeral neck, just distal to the joint. Therefore, the axillary nerve and deltoid almost always are sacrificed during proximal humerus resections.

Radial Nerve The radial nerve comes off the posterior cord of the plexus and continues anterior to the latissimus dorsi and teres major. Just distal to the teres major, the nerve courses into the posterior aspect of the arm to run between the medial and long head of the triceps. Although most sarcomas of the proximal humerus do not involve the radial nerve, it must be isolated and protected prior to resection. Axillary and Brachial Arteries The axillary artery is a continuation of the subclavian artery and is called the brachial artery after it passes the inferior border of the axilla. The axillary vessels are surrounded by the three cords of the brachial plexus. The axillary artery typically leaves the lateral cord just distal to the coracoid process, passes through the coracobrachialis, and runs between the brachialis and biceps. Preservation of the musculocutaneous nerve and short head of the biceps muscle is important to ensure normal elbow function. The path of this nerve may vary extensively (within 2 to 8 cm of the coracoid) and should be identified before any resection is performed because the nerve can easily be injured. The axillary nerve arises from the posterior cord and courses, along with the circumflex vessels, inferior to the distal border of the subscapularis. It then is tethered to the proximal humerus by the anterior and posterior circumflex vessels. Early ligation of the circumflex vessels is a key maneuver in resection of proximal humeral sarcomas because it allows the entire axillary artery and vein to fall away from the tumor mass. Occasionally, anatomic variability in the location of the branches of the nerve may lead to difficulty in identification and exploration if the variation has not previously been recognized. A preoperative angiogram is helpful in determining vascular displacement and anatomic variability. P.106 Final determination of tumor resectability is made at surgery. Early exploration of the neurovascular structures is performed following division of the pectoralis major muscle. This approach does not jeopardize subsequent http://e-surg.com

formation of an anterior flap in patients who require forequarter amputation.

FIG 3 • A. Osteosarcoma of the proximal humerus showing typical intramedullary ossification and an extraosseous soft tissue ossification. In general, a sarcoma of the proximal humerus involves one-third to onehalf of the length of the bone. This length of bone must be resected in addition to the adjacent joint. B. Bone scan showing the amount of uptake corresponding to the radiograph shown in A. In general, a resection is performed 3 to 4 cm distal to the area of uptake, as correlated with findings on an MRI scan, which is the imaging modality that best shows intramedullary extension of the tumor. C. Plain radiograph showing a radiolucent tumor of the proximal humerus. A needle biopsy confirmed that this was a giant cell tumor (GCT). CT shows minute fractures through the cortices, and the tumor was determined to be a stage III GCT. This patient was treated by primary resection of the proximal humerus. The procedure was classified as a type IA resection, and the humerus was reconstructed with an endoprosthetic modular prosthesis. Intra-articular resections are unusual for the proximal humerus because most tumors are high grade with soft tissue components. D,E. Postoperative imaging studies are useful to determine response to induction chemotherapy. D. The CT scan shows complete reossification of a lesion of the proximal humerus without any major soft tissue component. The plain radiograph shows healing at the site of a former pathologic fracture without any evidence of extraosseous formation. In general, CT scanning and plain radiography are reliable to demonstrate a good clinical response. E. Osteosarcoma of the proximal humerus, which does not show any evidence of an extraosseous component or http://e-surg.com

any joint involvement. F. Schematic diagram of biopsy technique for tumors of the proximal humerus. The biopsy should be performed through the anterior one-third of the deltoid, and the deltopectoral groove must be avoided. A core biopsy is recommended. (F: From Bickels J, Jellnek S, Shmookler BM, et al. Biopsy of musculoskeletal tumors: current concepts. Clin Orthop Relat Res 1999;368:212-219.)

IMAGING AND OTHER STAGING STUDIES Appropriate imaging studies are key to successful resections of tumors of the proximal humerus and shoulder girdle (FIG 3A-E). The most useful imaging studies are plain radiography, computed tomography (CT) scans, magnetic resonance imaging (MRI), P.107 arteriography, and bone scan. Venography is only occasionally required.

Computed Tomography CT is most useful for evaluating cortical bone changes and is considered complementary to MRI in evaluating the chest wall, clavicle, and axilla for tumor extension (FIG 3D).

Magnetic Resonance Imaging MRI is useful to identify intraosseous tumor extent, which is necessary for determining the length of bone resection. It is the best imaging modality for evaluation of soft tissue tumor involvement, especially around the glenohumeral joint, suprascapular region, and chest wall.

Bone Scintigraphy Bone scintigraphy is used to determine the intraosseous tumor extent and to detect metastases (see FIG 3B).

Angiography Angiography is useful for evaluation of tumor vascularity and tumor response to neoadjuvant chemotherapy. It also is essential for determining the relation of the brachial vessels to the tumor or the presence of anatomic anomalies. A brachial venogram also may be necessary if there is evidence of distal venous obstruction suggesting a tumor thrombus. It is also relevant in cases where the decision to amputate is conflictive. Repeat staging studies are typically performed following surgical resection to determine patient response to chemotherapy.

Biopsy Needle or incisional biopsies of tumors of the proximal humerus should be performed through the anterior onethird of the deltoid muscle, not through the deltopectoral interval (FIG 3F). A biopsy through the anterior one-third of the deltoid results in a limited hematoma that is confined by the deltoid muscle. This portion of the muscle and any biopsy hematoma are easily removed at the definitive resection. A biopsy taken through the deltopectoral interval will contaminate the major pectoralis muscle, which is necessary for reconstruction; increase the risk of hematoma spread along the axillary vessels to the chest wall; and make a local resection difficult, if not impossible. If an open biopsy is required, a short longitudinal incision should be made just lateral to the deltopectoral interval. The dissection should be directly into the deltoid muscle and proximal humerus. http://e-surg.com

The bone should be exposed lateral to the long head of the biceps. No flaps should be developed, and the glenohumeral joint should not be entered.

TECHNIQUES ▪ Resection Techniques It is important to be extremely familiar with shoulder girdle anatomy and axillary and vascular structures. A utilitarian incision is used (TECH FIG 1A-D). The anterior component is an extended deltopectoral incision that exposes the pectoralis major muscle, which is then released and retracted toward the chest wall. This exposes the axillary contents and permits exploration and safe dissection of the vascular structures and infraclavicular plexus (TECH FIG 1E). An extra-articular resection is performed. Thus, the axillary nerve is identified and transected. The musculocutaneous nerve is identified and preserved (TECH FIG 1F). The radial nerve, which crosses the humerus posteriorly at the level of the deltoid insertion, is preserved. Approximately one-half to two-thirds of the humerus is resected (TECH FIG 1G). An extra-articular resection is performed by exposing the glenohumeral joint both anteriorly and posteriorly. The scapula is osteotomized medial to the coracoid along with the distal portion of the clavicle. The resected specimen consists of the proximal one-half of the humerus, the glenohumeral joint, and the distal clavicle en bloc. A modular replacement proximal humeral prosthesis is used to reconstruct the skeletal defect (TECH FIG 2). Attention must be paid to the reconstruction of the muscles for soft tissue coverage of the prosthesis. Static suspension is performed with Dacron tape, and the muscle reconstruction is performed with the pectoralis major muscle sutured to the remaining scapula. The remaining muscles are then tenodesed to the pectoralis major muscle. This technique permits immediate stability and restores motor power to the upper extremity (TECH FIG 3A,B). An epineural axillary sheath catheter is used to control postoperative pain. A 28-gauge chest tube is used for drainage through a Pleurovac (TECH FIG 3C). Postoperatively, the patient uses a sling for 2 weeks. Endoprosthetic Replacement of the Proximal Humerus The Modular Replacement System (MRS; Stryker Orthopaedics, Mahwah, NJ), which is used for reconstruction of the shoulder girdle, is shown. Results of the MRS are predictable and successful, and the device is used for both intra- and extra-articular resections. Endoprosthetic reconstruction following tumor resection entails the following steps: Fixation of the endoprosthesis in the remaining distal humerus Fixation and stabilization of the prosthetic humeral head to the scapula to provide a stable shoulder joint Soft tissue reconstruction to cover the prosthesis completely and optimize postoperative function P.108

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TECH FIG 1 • A. Utilitarian incision used by the authors for exposure of the proximal humerus, scapula, or shoulder girdle. B. The utilitarian approach is used for extra-articular resections of the shoulder girdle. Exposure of the anterior aspect and the axillary space routinely is performed by releasing two layers of muscle. The pectoralis major is released from its insertion onto the proximal humerus and reflected back onto the chest wall. This step exposes the entire axillary area, including the infraclavicular portion of the brachial plexus, the axillary artery and vein, the coracoid and scapula, and the corresponding muscles. C. Following reflection of the pectoralis major, the second muscle layer must be developed and detached and retracted. This layer consists of the pectoralis minor and the short head of the biceps. Each of these muscles has attachments to the coracoid. It is important to dissect the musculocutaneous nerve from around the coracoid as it enters the short head of the biceps to avoid nerve injury. These muscles are detached and retracted medially and distally, respectively, to expose the entire axillary fascia, which then can be opened to accomplish the following dissection. It is important to dissect the musculocutaneous nerve from around the coracoid as it enters the short head of the biceps. (continued) P.109 http://e-surg.com

TECH FIG 1 • (continued) D. Position and incision. Antibiotics are begun preoperatively and continued until suction drains are removed. The patient is placed in an anterolateral position that allows some mobility of the upper torso. A Foley catheter is placed in the bladder, and an intravenous line is secured in the opposite extremity. The skin is prepared down to the level of the operating table, to the umbilicus, and cranially past the hairline. The incision starts over the junction of the inner and middle thirds of the clavicle. It continues along the deltopectoral groove and then down the arm over the medial border of the biceps muscle. The biopsy site is excised, leaving a 3-cm margin of normal skin. The posterior incision is not opened until the anterior dissection is complete. E. Exploration of the axilla to determine resectability. The skin is opened through the superficial fascia, but care is taken to preserve the deep fascia of muscles. Anteriorly, the skin flap is dissected off the pectoralis major muscle to expose its distal third, and the short head of the biceps muscle is uncovered. The pectoralis major muscle overlying the axilla is dissected free of axillary fat so that its insertion on the humerus can be visualized; this muscle is divided just proximal to its tendinous insertion on the humerus, and the portion of the muscle remaining with the patient is tagged with a suture. Next, the axillary sheath is identified and the coracoid process visualized. To expose the axillary sheath along its full extent, the pectoralis minor short head of the biceps and coracobrachialis muscles are divided at their http://e-surg.com

insertion on the coracoid process. All proximal muscles are tagged with sutures for later identification and use in the reconstruction. (continued) P.110

TECH FIG 1 • (continued) F. Dissection of the neurovascular bundle. Vessel loops are passed around the neurovascular bundle near the proximal and distal ends of the dissection. Medial traction on the neurovascular bundle allows visualization of the axillary nerve, posterior circumflex artery, and anterior circumflex artery. These structures are ligated and then divided. If the neurovascular bundle is found to be free of tumor extension, dissection for the limb salvage procedure proceeds. The musculocutaneous nerve is isolated and carefully preserved, although this nerve sometimes must be sacrificed to preserve tumor-free margins. Its loss results in lack of elbow flexion following surgery. The deep fascia between the short and long heads of the biceps muscle is divided below the tumor mass to separate the short and long heads of the biceps maximally, permitting easy visualization of the musculocutaneous nerve. The radial nerve is identified at the lower border of the latissimus dorsi muscle, passing around and behind the humerus into the triceps muscle group. The profunda brachialis artery that accompanies this nerve may be ligated. The radial nerve passes posterior to the humerus in its midportion (spiral groove). To dissect it free of the bone, http://e-surg.com

a finger is passed around the humerus to bluntly move the nerve away from the bone. G. Division of the muscle groups anteriorly to expose the neck of the scapula. The short and long heads of the biceps are widely separated to expose the humerus. The site for the humeral osteotomy is determined, and then the long head of the biceps and brachialis muscles are transected at this level. The inferior border of the latissimus dorsi muscle is identified, and a fascial incision is made that allows one to pass a finger behind the latissimus dorsi and teres major muscles several centimeters from their insertion into the humerus or scapula. The latissimus dorsi and teres major muscles are transected using electrocautery. External rotation of the humerus exposes the subscapularis muscle, which is transected at the level of the coracoid process. Care must be taken not to enter the joint space. The portions of these muscles that are not to be removed during the resection are tagged for future reconstruction. By transecting these muscles, the anterior portion of the neck of the scapula has been exposed. (C,D,F,G: Courtesy of Martin M. Malawer; E: From Malawer MM. Tumors of the shoulder girdle: technique of resection and description of a surgical classification. Orthop Clin North Am 1991;22:7-35.) P.111

TECH FIG 2 • Various methods used for reconstruction of the proximal humerus following resection for highgrade sarcomas between 1960 and 1990. A. The first attempts to regain length used the Kirschner rod fixated into the distal humerus and sutured to the clavicle with wires or heavy sutures. This failed and often caused proximal protrusion through the skin. B. The long-stemmed Neer prosthesis was developed to reestablish humerus length and to avoid the problem of proximal migration. C. The first custom prosthesis developed in the mid-1970s to reconstruct the proximal humerus in an anatomic format. This had both external phalanges and a small stem. D. The MRS is the type of prosthesis currently used. An MRS has a head, body, and stem of various diameters and lengths so that it can be modified intraoperatively for each http://e-surg.com

patient's anatomic needs. No waiting period for a custom prosthesis to be made is required, as formerly was the situation. The first proximal humerus prosthesis of the MRS type was implanted in Washington, DC in 1988. (A-D: Courtesy of Martin M. Malawer.) Dual Suspension Technique A dual suspension (ie, static and dynamic) technique is used to create shoulder stability (TECH FIG 4). In the static reconstruction, drill holes are made in the distal portion of the osteotomized clavicle and through the remaining scapula at the level of the spine. The head of the prosthesis is secured to the remaining portion of the scapula with 3-mm Dacron tape so that the prosthesis is suspended mediolaterally to provide horizontal stability. It then is suspended, using more Dacron tape, in a craniocaudal direction from the end of the clavicle to provide vertical stability. Dynamic suspension is provided by transfer of the short head of the biceps muscle to the stump of the clavicle (as described in the next section), which allows elbow flexion. Soft Tissue Reconstruction The remaining muscle groups are tenodesed to the pectoralis major and osteomized border of the scapula with Dacron tape. This mechanism offers dynamic support, assists in the suspension of the prosthesis, and provides soft tissue coverage. Soft tissue coverage is essential to cover the prosthesis and prevent skin problems and secondary infections. Type I Resection Intra-articular resection of the proximal humerus is indicated for low-grade sarcomas or high-grade sarcomas confined to the bone without extraosseous extension (stage IIA; TECH FIG 5A,B). The abductor mechanism and axillary nerve usually are preserved. This procedure is not recommended for high-grade sarcomas with soft tissue extension. The prosthesis is suspended from the glenoid with a Gore-Tex graft, which is reinforced by any remaining capsule (TECH FIG 5C-E). Anterior utilitarian shoulder incision is not required. The posterior component is not used. The axillary nerve is explored early and preserved. If there is tumor extension to the nerve, then the procedure is converted to a type V resection. P.112

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TECH FIG 3 • A. Securing the prosthesis. If a prosthesis is to be used, 5 to 7 cm of distal humerus must be preserved. A power reamer is used to widen the medullary canal of the remaining humerus; it is reamed until it is 1 mm larger than the stem of the prosthesis. The bony specimen is measured so that a prosthesis of appropriate length is used. Methylmethacrylate cement is injected into the medullary canal, and the prosthesis is positioned. The head of the prosthesis should be oriented so that it lies anterior to the transected portion of scapula while the arm is in neutral position. The radial nerve should be positioned anterior to the prosthesis so it does not become entrapped between muscle and prosthesis during the reconstruction. Drill holes are made through the scapula at the level of its spine and also through the distal portion of the transected clavicle. The head of the prosthesis is secured by 3-mm Dacron tape to the remaining portion of the scapula so that the prosthesis is suspended mediolaterally, providing horizontal stability. It is suspended in a craniocaudal direction by a second 3-mm Dacron tape from the end of the clavicle for vertical stability. B. Reconstruction. The pectoralis minor muscle is sutured to the subscapularis muscle over the neurovascular bundle to protect it from the prosthesis. The pectoralis major muscle is closed over the prosthesis to the cut edge of the scapula and secured with nonabsorbable sutures through drill holes. Following this, the trapezius, supraspinatus, infraspinatus, and http://e-surg.com

teres minor muscles are secured to the superior and lateral borders of the transected pectoralis major muscle. The teres major and latissimus dorsi muscles are secured to the inferior border of the pectoralis major muscle. The tendinous portion of the short head of the biceps is secured anteriorly under appropriate tension to the remaining clavicle. The long head of the biceps and the brachialis muscles are sutured to the short head of the biceps muscle under appropriate tension so that these two muscles can work through the short biceps tendon. The remaining triceps muscle is secured anteriorly along the lateral border of the biceps to cover the lower and lateral portion of the shaft of the prosthesis. Ideally, when the proximal and distal muscular reconstruction is complete, the prosthesis is covered in its entirety by muscle. C. Closure. Large-bore suction catheter drainage is secured. The superficial fascia is closed with absorbable suture, and the skin is closed with clips. Povidone-iodine ointment is applied to the incision along with a dry sterile dressing. A sling and swathe are applied in the operating room. (A,B: From Rubert CK, Malawer MM, Kellar KL. Modular endoprosthetic replacement of the proximal humerus: indications, surgical technique, and results. Semin Arthroplasty 1999;10:142-153; C: Courtesy of Martin M. Malawer.) P.113

TECH FIG 4 • Reconstruction of the proximal humerus. A. The initial reconstruction is performed by suspending the humeral prosthesis from the subscapular fossa by transverse and horizontal tapes. These are brought through the prosthesis and the holes in the scapula and clavicle, providing for immediate stability. B. The prosthesis being placed anterior (not lateral) to the scapula and into the subscapular fossa. The pectoralis major and subscapularis muscle are sutured with 3-mm Dacron tape through drill holes of the axillary border of the scapula, providing immediate and excellent stability. C. Gore-Tex graft is used to reconstruct the capsule if an intra-articular resection is performed. http://e-surg.com

The humeral prosthesis is suspended from the glenoid labrum with 32-mm Gore-Tex. The remaining capsule is sutured to the new Gore-Tex capsule. This step avoids glenohumeral joint subluxation and dislocation. Total Humeral Resection and Prosthetic Reconstruction Total humeral replacement is unusual but is indicated when the tumor involves a large portion of the diaphysis, such as in Ewing sarcoma, or when an extremely short segment of distal humerus remains following adequate tumor resection. The surgical technique is a combination of that used for proximal and distal humerus resections. Reconstruction provides stability of both shoulder and elbow joints. Exposure and Extension of Type V Procedure The surgical approach is similar to that used for a type V resection (ie, anterior utilitarian approach), but it requires additional distal exposure and identification and mobilization of the brachial artery and vein and the radial, ulnar, and median nerves (TECH FIG 6). The incision and exposure are continued down the anteromedial aspect of the arm, across the antecubital fossa, and, if necessary, down the anterior aspect of the forearm. The brachial vessels, along with the median and ulnar nerves, are identified medially in the arm. The medial intermuscular septum is transected to allow further dissection and mobilization of the ulnar nerve so that it can be retracted medially with the brachial vessels and median nerve. The biceps is retracted medially with the neurovascular bundle. The radial nerve is identified where it passes around the humerus and into the interval between the brachialis and brachioradialis muscles and continues into the forearm. The pronator teres and common flexor origins are transected medially, and the brachioradialis, extensor carpi radialis longus, and common extensor origins are released laterally to expose the distal humerus. A small cuff of muscle is left around the tumor as needed. The medial triceps muscle usually is resected with the tumor, but the lateral and long heads are retained. The triceps tendon is kept attached to the olecranon. The olecranon is not osteotomized. The elbow joint is opened anteriorly and the capsule released circumferentially. The humeroulnar and radiohumeral joints are then disarticulated. Prosthetic Reconstruction, Muscle Reconstruction, and Postoperative Management Reconstruction of the total humerus is similar to that of the proximal humerus. Distally, an ulnar endoprosthetic component with an intramedullary stem is cemented, with the olecranon left intact. Several articulating elbow devices are available. The reconstruction technique is similar to that used for the proximal humerus, with the addition of distal soft tissue and joint capsule reconstruction. The brachioradialis, pronator teres, and flexor carpi radialis muscles are sutured to the remaining biceps and triceps muscles to secure soft tissue around the flared distal portion of the humeral endoprosthesis. The remaining muscles are closed in layers in an attempt to cover the entire prosthesis. A posterior splint is used to protect the elbow reconstruction for 7 to 10 days. The surgical incision and wounds are examined on the fourth to fifth postoperative day. P.114

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TECH FIG 5 • Intraoperative photographs of an intra-articular resection. A. The tumor has been removed, demonstrating the relation of the axillary nerve to the capsule and the glenoid. The brachial vessels have been mobilized and are seen in the vessel loop. The structures around the proximal humerus are in close proximity to the subscapularis muscle and the joint capsule. These vessels are initially identified and retracted prior to resection. B. Reconstruction of the proximal humerus is performed with the MRS. It is essential to reconstruct the capsule because soft tissue reconstruction alone will not maintain any stability either of the humeral head or to the shallow glenoid. Therefore, a Gore-Tex graft is used and is sutured to the rim of the glenoid. The humeral head then is reduced within this sleeve and sutured, using Dacron tape, through holes in the humeral head. This is the technique routinely used for intra-articular resections of the proximal humerus. C-E. Schematic of a proximal humerus reconstruction with static and dynamic transfers as well as a proximal humeral prosthesis. This technique, which has been used by Malawer since 1988, provides excellent coverage of the prosthesis and stability with active motion of the new glenohumeral joint. The prosthesis is suspended from the remaining axillary border of the scapula with two Dacron tapes and with additional tapes from the prosthesis to the clavicle. Therefore, both longitudinal and horizontal stabilizing forces are in place. The soft tissue reconstruction consists of the long head of the biceps being attached to either the clavicle or the transferred pectoralis major muscle. The prosthesis is covered with four muscles. The pectoralis major and subscapularis muscles are sutured over the prosthesis to the remaining border of the scapula through drill holes using Dacron tape. This provides immediate stability and http://e-surg.com

good coverage of the prosthesis. The prosthetic head is placed anterior to the scapula, not at the lateral border, and is then placed in the subscapular fossa. The remaining muscles of the teres and the infraspinatus are brought anteriorly and sutured, and the trapezius muscle is mobilized at the base of the neck to the area of muscle reconstruction. (C-E: From Rubert CK, Malawer MM, Kellar KL. Modular endoprosthetic replacement of the proximal humerus: indications, surgical technique, and results. Semin Arthroplasty 1999;10:142-153.) P.115

TECH FIG 6 • A. Operative specimen of the resection of a proximal humeral osteosarcoma. This is classified as a stage VB resection, that is, an extra-articular proximal humeral and glenohumeral resection. Most large sarcomas of the proximal humerus involve the deltoid and surrounding tissues as well as the axillary nerve, with a high propensity of cancellar tumor involvement; therefore, we routinely recommend an extra-articular resection. B. Radiograph of the same specimen showing the scapula where it was osteotomized medial to the coracoid. The entire joint was removed en bloc along with the proximal third of the humerus. C. Gross specimen of an osteosarcoma showing involvement of the soft tissues and extending into the capsule (arrow).

PEARLS AND PITFALLS Nonablative

▪ This chapter contains a complete description of the technique for a modified Tikhoff-Linberg procedure in patients with

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extirpation rare

sarcomas of the proximal humerus. Modifications of the procedure also have been used for tumors at other anatomic sites. Proximal humeral lesions require resection of about two-thirds of the humerus. ▪ The technique of resection and reconstruction requires a thorough knowledge of the regional anatomy and technique of musculoskeletal reconstruction. Essential aspects of the treatment plan should be emphasized.

Biopsy

▪ The initial biopsy should be performed through the anterior portion of the deltoid muscle for a lesion of the proximal humerus. The deltopectoral interval should not be used because biopsy here would contaminate the deltopectoral fascia, the subscapularis, and the pectoralis major muscles and would jeopardize the possibility of performing an adequate resection through uninvolved tissue planes.

Incision

▪ For the definitive resection, the initial incision extends along the medial aspect of the biceps muscle, divides the pectoralis major, and exposes the neurovascular structures, thereby enabling the surgeon to determine resectability early in the dissection. ▪ This incision does not jeopardize construction of an anterior skin flap in patients who will require forequarter amputation.

Resection

▪ The length of bone resection is determined preoperatively from a bone scan and MRI. To avoid a positive margin at the site of humeral transection, the distal osteotomy is performed 3-5 cm distal to the area of abnormality on the scan. ▪ Alternatively, other surgeons use autografts (usually fibulas) or allografts as spacers in obtaining an arthrodesis. We do not recommend osteoarticular allografts or intra-articular resections for high-grade bone sarcomas; those techniques were developed during the 1960s and 1970s and are inferior to current standards. Superior results routinely are obtained with modular prosthetic replacements combined with reconstruction of the soft tissues (FIG 4).

Reconstruction

▪ Segmental reconstruction of the resultant humeral defect is necessary to create shoulder stability. We do not leave a flail extremity. Reconstruction is necessary to maintain length of the arm and to create a fulcrum for elbow flexion. We recommend a custom or modular prosthesis. ▪ The key to success is reconstruction of the stability of the joint and soft tissue coverage of the prosthesis.

FIG 4 • Original photograph taken following an extra-articular resection of a large section of the proximal humerus and scapula involved by an osteosarcoma during the late 1960s. This was one of the first shoulder http://e-surg.com

girdle resections performed in the United States. Notice the marked shortening of the limb but the fairly normal functioning of the hand and elbow. Subsequently, multiple techniques have been used to maintain the length and function of the shoulder girdle. (Courtesy of Ralph C. Marcove, MD.)

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OUTCOMES The proximal humerus resection, the prosthetic reconstruction and muscle plasty, is a very reliable procedure with good oncologic and functional results.4 Pain is well controlled in the majority of patients. The motor dexterity of the hand and the range of motion (ROM) of the elbow and wrist generally are preserved. The Musculoskeletal Tumor Society upper extremity functional scores ranged from 24 to 27 (80% to 90%) with stable shoulders in the vast majority of the patients. Normally, all patients could do activities of daily life with the involved extremity. Some restrictions in activities can be seen, but most patients are capable of participating in some recreational activities. Most restrictions are seen in high-level athletes.1,4 Prosthetic survival is optimal with extremely low percentages of loosening and revisions. The rate of dislocation is minimal if static and dynamic reconstruction technique is followed.

COMPLICATIONS Neurologic complications are infrequent and transient. Normally, 6 to 12 months after the surgery, all the nerve palsies are resolved. Neurapraxias due to late traction from the weight of the upper extremity occurs rarely. Loss of function is contingent on the extent of the muscle resection. Patients who present with extensive tumors around the shoulder girdle tend to have decreased ROM. Skin necrosis and superficial infections are uncommon. Dislocation of the shoulder is seen in less than 5% of the cases and no surgery is required.

REFERENCES 1. Cannon CP, Paraliticci GU, Lin PP, et al. Functional outcome following endoprosthetic reconstruction of the proximal humerus. J Shoulder Elbow Surg 2009;18(5):705-710. 2. Malawer MM, Link M, Donaldson S. Sarcomas of bone. In: Devita VT, Hellman S, Rosenberg SA, eds. Cancer: Principles and Practice of Oncology, ed 3. Philadelphia: JB Lippincott, 1989. 3. Malawer MM, Sugarbaker PH, Lambert MH, et al. The Tikhoff-Linberg procedure and its modifications. In: Sugarbaker PH, ed. Atlas of Sarcoma Surgery. Philadelphia: JB Lippincott, 1984. 4. Wittig JC, Bickels J, Kellar-Graney KL, et al. Osteosarcoma of the proximal humerus: long-term results with limb-sparing surgery. Clin Orthop Relat Res 2002;(397):156-176. http://e-surg.com

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Chapter 11 Distal Humeral Resection with Prosthetic Reconstruction James C. Wittig Martin M. Malawer

BACKGROUND The distal humerus is a relatively rare site for primary bone sarcomas. It is more commonly involved by neoplasm through metastatic spread. The distal humerus or elbow joint also can be secondarily involved by soft tissue sarcomas arising from the adjacent musculature or intermuscular soft tissues. Sarcomas that arise from the most proximal portions of the flexor-pronator group or common forearm extensor muscles may involve the distal humerus by direct invasion or by growing around the circumference of the distal humerus. Sarcomas that arise from the distal brachialis muscle or triceps muscle also may secondarily involve the distal humerus. Tumors arising in this area that involve the soft tissues are technically challenging to resect. These tumors usually are juxtaposed to and displace the adjacent neurovascular structures that lie in immediate proximity to the distal humerus and within the antecubital fossa. The key to a safe and successful resection lies in identifying and mobilizing all important neurovascular structures (eg, brachial artery and vein, median nerve, ulnar nerve, and radial nerve) away from the neoplasm and distal humerus. The biceps muscle must be preserved in order to restore elbow flexion after reconstruction. Each of the neurovascular structures is identified proximal to the tumor, in normal tissue, in the distal one-third of the arm. These structures are dissected in a proximal to distal direction, separated from the neoplasm, and mobilized across the elbow joint. Once these structures are mobilized and protected, it is safe to proceed with removing the distal humerus and tumor en bloc. In most cases, even the most extreme cases, the neurovascular structures are displaced and not encased by neoplasm, making limb-sparing surgery an option in lieu of an amputation (FIG 1). Gross tumor involvement of a single nerve is not an absolute indication for an above-the-elbow amputation. Involvement of more than one major nerve or the main vascular supply is an indication for an above-the-elbow amputation when treating a sarcoma with curative intention. In cases of metastatic carcinomas, where treatment is palliative, adjuvant treatments such as radiation or chemotherapy should be considered before proceeding with an amputation. Prosthetic reconstruction of the distal humerus and elbow joint with a modular, segmental, tumor prosthesis including a semiconstrained, hinged elbow joint is a reliable means of skeletal reconstruction following resection. Multiple muscle rotation flaps, retensioning the biceps muscle, and flexorplasty of the forearm musculature are key steps to restoring elbow flexion power.

ANATOMY To resect tumors involving the distal humerus safely and adequately, the major neurovascular structures around the distal humerus should be exposed and identified. In the middle one-third of the arm, most of the important neurovascular structures lie within a fibrous sheath, in the groove between the biceps and triceps muscles, along the medial side of the arm, just medial to the brachialis muscle. These structures include the following: The brachial artery, which is surrounded by two small brachial veins http://e-surg.com

The median nerve, which lies directly anterior to the brachial artery The cephalic vein and medial antecubital cutaneous nerve, which lie superficial to the brachial artery The ulnar nerve, which is surrounded by the superior ulnar recurrent artery and two veins that lie just medial and posterior to the brachial artery The medial brachial cutaneous nerve, which lies in the superficial subcutaneous tissue at this level At this level, the radial nerve lies within the spiral groove of the humerus along the posterolateral aspect of the arm. The brachial artery and veins are the continuation of the axillary artery and vein at the level of the lower border of the subscapularis muscle. The brachial artery and veins travel distally along the medial side of the arm, deep to the fascia, in the interval between the biceps and triceps muscles, medial to the brachialis muscle. The profunda brachii artery arises proximally from the brachial artery at the lower border of the latissimus dorsi P.118 muscle. It traverses dorsally and laterally with the radial nerve and enters the spiral groove.

FIG 1 • Postoperative radiograph showing a distal humeral prosthesis and elbow joint. This prosthesis was inserted to avoid an amputation. The brachial artery gives off several branches along its course to the biceps, brachialis, and triceps muscles. In the antecubital fossa, the brachial artery lies on the anterior surface of the brachialis muscle, immediately http://e-surg.com

adjacent and lateral to the median nerve. The brachial artery passes just deep to the bicipital aponeurosis to enter the forearm. The inferior ulnar collateral artery arises from the brachial artery just proximal to the bicipital aponeurosis and passes medially just along the proximal aspect of the medial condyle of the humerus. After the brachial artery passes underneath the bicipital aponeurosis, it branches into the ulnar artery, radial recurrent artery, and radial artery. The median nerve travels distally in the arm, closely applied to the anterior aspect of the brachial artery. As the median nerve approaches the antecubital fossa, it crosses over medially so that it occupies a position immediately medial to the brachial artery and lateral to the pronator teres muscle in the antecubital fossa. The ulnar nerve occupies a position slightly more medial and posterior to the brachial artery in the midarm. In the distal one-third of the arm, the ulnar nerve travels posteriorly and pierces the medial intermuscular septum. It travels along the medial side of the triceps muscle and enters a groove (cubital tunnel) along the posterior aspect of the medial epicondyle of the humerus. The ulnar nerve is tethered within this groove by ligamentous tissue. It then travels distally and enters the forearm by passing through the humeral and ulnar heads of the pronator teres muscle. In the forearm, the ulnar nerve lies along the deep surface of the flexor carpi ulnaris muscle. The medial antebrachial cutaneous nerve is a small nerve that lies deep to the fascia between the median and ulnar nerves at the midarm level. In the distal one-third of the arm, the nerve occupies a more superficial position in the subcutaneous tissue. The radial nerve arises from the posterior cord of the brachial plexus. At the inferior border of the latissimus dorsi muscle, the radial nerve passes posteriorly, along with the profunda brachii artery, through the interval between the long head of the triceps and the humerus. The radial nerve enters the spiral groove of the humerus and travels distally, wrapping around the posterior aspect of the humerus, in the interval between the medial and lateral heads of the triceps muscle. In the distal one-third of the arm, the radial nerve passes through the lateral intermuscular septum and enters the anterior compartment of the arm, where it resides in the interval between the brachioradialis muscle and brachialis muscle. The radial nerve continues distally into the forearm. At the lower, lateral border of the brachialis muscle, just proximal to the supinator muscle, the radial nerve divides into the posterior interosseous nerve and the superficial radial nerve. The posterior interosseous nerve passes through the substance of the supinator muscle. The superficial radial nerve travels distally along the deep surface of the brachioradialis muscle.

INDICATIONS AND CONTRAINDICATIONS Indications High-grade and some low-grade bone sarcomas Soft tissue sarcomas that surround or invade the distal humerus or elbow joint secondarily Solitary metastatic carcinomas to the distal humerus Metastatic carcinomas that have destroyed a significant portion of the distal humerus, which precludes other methods of resection and fixation Local complications resulting from other treatments for tumors involving the distal humerus (eg, nonunion of a pathologic fracture following radiation, untreatable infection of bone after prior surgery)

Contraindications Absolute contraindications include tumor involvement of the neurovascular bundle. http://e-surg.com

Involvement of a single major nerve is not an absolute contraindication. The nerve can be resected with the neoplasm. Encasement of the brachial artery and veins or two or more major nerves usually precludes a limb-sparing resection. Final determination regarding the need for an amputation is made at the time of surgery, after the neurovascular structures are explored. Adjuvant treatments such as radiation and chemotherapy should be considered for palliation of metastatic carcinomas prior to proceeding with an amputation. Relative contraindications include tumor contamination of the operative site from hematoma following a poorly performed biopsy or pathologic fracture or a previous or active infection. Recently, we have successfully treated patients with pathologic fractures with induction chemotherapy, immobilization, and limb-sparing surgery if there is a good clinical response and fracture healing; survival has not been compromised, and local recurrence is less than 10%.

IMAGING AND DIAGNOSTIC STUDIES The most useful imaging studies are plain radiography, computed tomography (CT), magnetic resonance imaging (MRI), arteriography, and bone scan. These studies are useful for diagnosis; evaluating local and distant extent of disease; and, for select sarcomas, gauging the response to preoperative chemotherapy. Radiologic studies are necessary to determine the exact anatomic extent of the neoplasm so that the surgical procedure can be planned accurately.

Plain Radiographs Plain radiographs of the humerus and elbow are used to localize the anatomic origin of the tumor, formulate a differential diagnosis, and estimate tumor extent (FIG 2A). After preoperative chemotherapy for an osteosarcoma, plain radiographs can be used to estimate the response of the tumor to the chemotherapeutic agents. A good response (>90% tumor necrosis) is indicated by extensive tumor calcification, periosteal new bone formation, and healing of pathologic fractures.

Computed Tomography CT is most useful for evaluating cortical bone changes and extent of cortical destruction by tumor. In the case of a metastatic carcinoma, it aids with decision making regarding the indication for a resection and prosthetic reconstruction versus curettage and internal fixation. Extensive cortical destruction throughout a significant circumference of the bone is an indication to proceed with a resection of the distal humerus and prosthetic reconstruction. CT also is useful for detecting subtle mineralization, calcification, or ossification within the neoplasm that may assist in diagnosis. P.119

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FIG 2 • A. Plain radiograph of a mesenchymal chondrosarcoma (arrows) of the distal humerus. Primary bone sarcomas are rare in this location. B. MRI scan showing the extent of the tumor. A distal humeral resection and reconstruction with a segmental prosthesis was performed. CT is considered complementary to MRI in evaluating the soft tissue component of the neoplasm and proximity to the neurovascular structures, particularly a contrast-enhanced CT scan. CT also assists with detection of subtle cortical erosion and frank invasion of the distal humerus by adjacent soft tissue sarcomas that may not be clearly delineated on MRI or plain radiographs. After preoperative chemotherapy of an osteosarcoma, CT characteristically shows a rimlike calcification in those tumors that have had a good response. Chest CT is most sensitive for detecting lung metastases.

Magnetic Resonance Imaging MRI is most accurate for determining intra- and extraosseous tumor extent as well as for detecting skip metastases. An appreciation of intraosseous extent is necessary for determining the length of bone resection. A post-chemotherapy MRI is fundamental in the preoperative plan. The humerus usually is transected approximately 2 to 3 cm proximal to the intramedullary extent of the neoplasm as visualized on a T1-weighted MRI scan. Proximity of the extraosseous component to the brachial vessels, median nerve, ulnar nerve, and radial nerve also can be evaluated, as can secondary involvement of the distal humerus and elbow joint by adjacent soft tissue sarcomas. Standard T1-weighted, T2-weighted, fat-suppressed, and gadolinium-enhanced images are recommended (FIG 2B).

Bone Scintigraphy http://e-surg.com

Bone scintigraphy is used to determine intraosseous tumor extent and is compared to the MRI scan to ensure accuracy. It also is used to detect bony metastases and skip metastases.

Positron Emission Tomography/Computed Tomography Positron emission tomography (PET)/CT is an imaging technique that allows measurement of the level of metabolic activity and perfusion in different organs. The most frequent radioactive substance used is fluorodeoxyglucose (FDG). PET/CT is used to detect the primary or metastatic tumors and recurrences after tumor treatment.

Thallium Scintigraphy Thallium 201 is a potassium analog that is actively transported by the sodium-potassium adenosine triphosphatase pump. A quantitative thallium scan has been useful for determining viability of bone tumors, particularly osteosarcomas. The affected side is compared to the unaffected side; a ratio below 4:1 is consistent with tumor necrosis greater than 90% (a good response).

Angiography Angiography is extremely useful for evaluation of tumor vascularity and is considered the gold standard for evaluating tumor response to neoadjuvant chemotherapy but is rarely used. High-grade sarcomas, such as osteosarcoma, demonstrate a tumor blush on an arteriogram when viable (fill with contrast dye because of extensive neovascularization of the tumor). The neovascularization and hence the tumor blush disappear when the tumor has had a good response to a preoperative chemotherapy regimen. It is also essential for determining the relationship of the brachial vessels to the tumor or the presence of anatomic anomalies. The soft tissue component of distal humeral tumors routinely displaces the brachial vessels. Soft tissue sarcomas that arise around the distal humerus also usually routinely displace the brachial vessels. The direction in which these structures are displaced can be determined with a biplanar arteriogram.

Biopsy Needle or incisional biopsies of tumors of the distal humerus should be performed through the brachialis muscle in line with the proposed skin incision so the biopsy tract can be excised at the time of the definitive procedure. The biopsy should never be performed through the biceps muscle; it should, rather, be performed along either side of the muscle. The biceps must be spared in order to be able to reconstruct the distal humerus and preserve elbow flexion. In general, the biopsy is best made directly anterior, just lateral to the biceps tendon or distal biceps muscle, close to the antecubital crease. In this manner, the biopsy tract can be excised with the transverse portion of the incision that crosses the antecubital crease. P.120 Occasionally, a very large soft tissue component that protrudes anteriorly and medially will displace the neurovascular structures medially. In these instances, it may be possible to biopsy the tumor under CT guidance for visualization of the neurovascular structures, just medial to the medial margin of the distal biceps muscle or biceps tendon. The tumor will occupy a subcutaneous position in this location and is easily biopsied. With either approach, it is important to perform the biopsy through the brachialis muscle and to avoid contaminating the biceps muscle. The portion of the brachialis muscle and biopsy hematoma are easily http://e-surg.com

removed at the definitive resection. Biopsy of a tumor arising from the brachioradialis or common extensor muscle origin is performed anteriorly, directly over the mass, along the lateralmost 1 to 2 cm of the antecubital crease. Extreme care is taken to avoid contaminating the radial and posterior interosseous nerves. Biopsy of a tumor arising from the flexor-pronator muscle group is performed at the most medial extent of the antecubital crease, directly over the mass and at a distance from the median nerve and brachial artery.

SURGICAL MANAGEMENT Preoperative Planning Staging studies are thoroughly reviewed before the surgical procedure. The T1-weighted coronal MRI scan of the entire humerus is reviewed. The length of the bone resection is based primarily on this study. The transection level is determined so that it will permit a 2- to 3-cm margin proximal to the intraosseous tumor extent. In the case of an adjacent soft tissue sarcoma, the bone is transected 2 to 3 cm proximal to the soft tissue involvement of the humerus. Surgical resection is modified to account for skip metastases, both intraosseous and transarticular. The length of the resection can be determined preoperatively to ensure all components of the prosthesis needed for reconstruction will be present. Nowadays, modular segmental prostheses are used that are assembled intraoperatively. The size can be adjusted intraoperatively to accommodate for the resection. The MRI and CT scans are reviewed to evaluate the exact degree of soft tissue extension and proximity to the neurovascular structures. CT and MRI results are evaluated to determine areas of the distal humerus or elbow joint that may be directly involved by an adjacent soft tissue sarcoma. The arteriogram provides a “road map” showing the direction of displacement of the neurovascular structures and also alerts the physician to any anomalies that may be encountered during surgery. Flexible reamers, sagittal saw, drill or high-speed burr, osteotomes, cement, cement gun, ball-tip guide wire, no. 5 nonabsorbable sutures, vessel loops, and ¼-inch Penrose drain will be required.

Positioning The patient is placed in a supine position with the arm abducted and placed on a padded and draped Mayo stand. A small bump is placed under the ipsilateral scapula to elevate the shoulder girdle slightly off the bed. The entire upper extremity, from the middle of the clavicle and shoulder girdle through the fingertips, is prepped and draped in a sterile manner.

Approach A limb-sparing distal humeral resection has three major components: Oncologic resection Skeletal reconstruction Soft tissue reconstruction or coverage (or both) The goal of the resection is to remove the entire tumor en bloc or, in other words, in one piece with the distal humerus. The key to the resection involves meticulously dissecting, separating, and mobilizing the important neurovascular structures away from the neoplasm. Skeletal reconstruction is done with a modular, segmental replacement that can be assembled and have its http://e-surg.com

size adjusted intraoperatively. The length of the prosthesis may be downsized as much as a few centimeters to facilitate soft tissue coverage of the prosthesis, if necessary. Soft tissue reconstruction that involves rotating and reattaching muscles and restoring the length-tension relationship of the forearm muscles and biceps is most important for achieving a good functional result and for protecting the prosthesis from infection.

TECHNIQUES ▪ Distal Humeral Resection The S-shaped incision begins in the middle of the arm along the medial side of the biceps muscle (TECH FIG 1A,B). It is extended distally along the medial border of the biceps muscle to the antecubital crease; the biopsy tract is included in the incision in an elliptical manner. At the antecubital crease, the incision curves laterally along the volar aspect of the elbow to the volar margin of the brachioradialis muscle, where it then turns distally and is extended distally along the forearm for a short distance. Medial and lateral cutaneous flaps are raised (TECH FIG 1C,D). Wherever possible, fasciocutaneous flaps are raised. Medial and lateral antebrachial cutaneous nerves are preserved. Proximally in the arm (proximal to the neoplasm in normalappearing tissues), in the interval between the biceps and triceps muscles, the neurovascular structures are identified within their sheath. The deep investing fascia of the arm (superficial layer of the sheath) is opened longitudinally directly over these structures. While protecting the underlying structures, the fascia is opened from proximally to distally all the way down to the neoplasm or antecubital fossa. The neurovascular structures can be visualized easily, and the brachial artery can be palpated once the sheath is opened. Proximally, the brachial artery and accompanying veins are isolated and surrounded with a vessel loop. Likewise, the median, ulnar, and medial antebrachial cutaneous nerves are each identified, isolated, and individually surrounded with a vessel loop. P.121

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TECH FIG 1 • A. An anterior surgical incision is routinely used for resection and prosthetic replacement of the elbow joint and distal humerus. The surgeon can palpate the normal anatomic structures. The longitudinal incision is made along the biceps-triceps interval. The joint is exposed through an S extension of the proximal incision. B. Schematic drawing of the anterior exposure. The neurovascular structures are identified (ie, brachial artery, median nerve, radial nerve, ulnar nerve) and retracted. This is essential for a safe procedure. (continued) P.122

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TECH FIG 1 • (continued) C. Wide medial and lateral flaps are required for adequate exposure. D. The biceps as well as the neurovascular structures are retracted. The brachial artery and veins are meticulously dissected away from the surrounding tissues and from the pseudocapsule of the neoplasm down to and across the antecubital fossa. The biceps aponeurosis is incised to permit visualization of the brachial artery to the point where the ulnar and radial arteries arise. The radial and ulnar arteries are each identified and surrounded with a vessel loop. The inferior ulnar collateral vessels, as well as muscular branches to the biceps, brachialis, or triceps muscle, may require ligation to mobilize the brachial vessels away from the neoplasm, depending on the location and position of the tumor. Once the artery is freed from the neoplasm, attention is turned to mobilizing the major nerves. The median nerve is dissected from a proximal to distal direction across the antecubital fossa, where it lies just medial to the brachial artery. It is dissected distally to where the anterior interosseous nerve arises from it and the median nerve continues deep to the flexor digitorum superficialis muscle. The ulnar nerve also is isolated and dissected from a proximal to distal direction. The medial http://e-surg.com

intermuscular septum is opened to allow further dissection and mobilization of the ulnar nerve to the cubital tunnel along the medial epicondyle of the distal humerus. The fascia or ligamentous tissue overlying the cubital tunnel is opened longitudinally, and the ulnar nerve is gently mobilized from the tunnel all the way to where the nerve passes between the humeral and ulnar heads of the pronator teres muscle. This enables the ulnar nerve to be retracted medially with the brachial vessels and median nerve. The radial nerve is identified in the interval between the brachioradialis and brachialis muscles. It is dissected distally across the elbow joint to the juncture where the posterior interosseous P.123 nerve originates from the radial nerve. It also is dissected proximally as it passes through the lateral intermuscular septum around the posterior aspect of the humerus in the spiral groove. The lateral intermuscular septum is opened, and the radial nerve is mobilized away from the posterior aspect of the humerus up to the latissimus dorsi muscle insertion. The biceps muscle is isolated, dissected away from neoplasm and the underlying brachialis muscle. Usually, the biceps is not involved by any neoplasm. If it is involved, a portion may require removal. (Be aware that the biceps or brachialis muscle is required for elbow flexion; removal of both in entirety prohibits elbow flexion postoperatively.) The biceps muscle is isolated so it can be retracted medially and laterally when necessary. The pronator teres and common flexor muscles are released from their origins from the distal humerus medially. The brachioradialis, extensor carpi radialis longus, and common extensor muscles are released laterally from the distal humerus. A small cuff of muscle is left around the tumor as needed. Occasionally, a distal humerus resection is performed for a soft tissue sarcoma that originates from one of these muscle groups. In such a case, the muscle or muscles that are involved by neoplasm are transected distal to the tumor in such a manner that an adequate margin is maintained. When resecting the flexor-pronator group, the branch of the median nerve that supplies the flexor digitorum superficialis is identified and protected, if possible. On the lateral side of the elbow, if the brachioradialis and common extensor muscles require resection, the posterior interosseous nerve is identified and protected to preserve wrist and digit extension.

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TECH FIG 2 • A. The appropriate length of resection is determined preoperatively from the MRI scan. In general, a 2- to 3-cm margin of normal bone is removed. B. Schematic drawing of the resection defect. C. Operative photograph of the surgical defect. Note the wide exposure. This is required for accurate positioning of the prosthesis and reaming of the ulnar canal. The triceps remains attached to the surrounding soft tissues. A portion of the brachialis muscle, or even the entire brachialis muscle, may require resection, depending on the extent of the tumor. If there is no soft tissue component arising from a distal humerus tumor or if the brachialis muscle is not involved by an adjacent soft tissue sarcoma, then the brachialis muscle is incised longitudinally along the anterior aspect of the distal humerus. The brachialis muscle is then elevated off the distal humerus and preserved. If there is a soft tissue component arising from a tumor of the distal humerus or if the brachialis muscle is involved by an adjacent soft tissue sarcoma, then the brachialis muscle is released in a subperiosteal manner from its insertion on the ulna or simply transected distal to the elbow joint. The triceps muscle is elevated off the distal humerus and may require partial or complete resection of the medial head, depending on tumor extent. The lateral and long heads usually can be preserved. The triceps tendon is kept attached to the olecranon. The olecranon is not osteotomized. The elbow joint is opened anteriorly and the capsule released circumferentially from the ulna-olecranon and radial head. The humeroulnar and radiohumeral joints are then disarticulated. The humerus is osteotomized at a level approximately 2 to 3 cm proximal to the intramedullary extent of the neoplasm (TECH FIG 2A). The area where the humerus will be osteotomized is cleared of overlying brachialis muscle and triceps muscle. The radial nerve is identified and protected before cutting the bone. The bone usually is transected with a sagittal saw (TECH FIG 2B,C). P.124 http://e-surg.com

▪ Prosthetic Reconstruction Reconstruction of the distal humerus and elbow joint is performed with a modular segmental distal humerus tumor prosthesis. The distal humeral component consists of a semiconstrained hinge component that is attached to an ulnar component to recreate the elbow joint. Proximally, the distal humeral component can be fit to a body segment via a Morse taper. The body segment is available in different lengths, so the size can be adjusted intraoperatively. The body segment is fit to a stem via a Morse taper. The stem then is cemented into the more proximal remaining humeral canal. The ulnar component consists of a stem that is cemented into the olecranon and proximal ulna. The ulnar component is available in two lengths. The length of the prosthesis is chosen. It may be downsized 2 to 3 cm to help facilitate soft tissue closure. The prosthesis is assembled on the field. The remaining humerus is flexibly reamed to accommodate as wide a stem as possible. It is overreamed 1 to 2 mm to accommodate for a cement mantle. The olecranon fossa is opened with a small high-speed burr (TECH FIG 3) to enter into the medullary canal of the proximal ulna. The proximal tip of the olecranon is shaved slightly to accommodate the ulnar stem so that it can be inserted directly into the ulnar canal without being inserted on an angle. The canal of the ulna is reamed with hand reamers. Trial components are available to be used to ensure that the ulnar component will sit properly within the medullary canal of the proximal ulna. Both components are cemented into place separately. The distal humerus is cemented so the hinge will face anteriorly. It is important to identify the anterior surface of the humerus before the distal humeral component is inserted. The ulnar component is placed so that it sits as deep as possible within the olecranon fossa without damaging the posterior cortex of the bone. After the cement cures, both components are attached to each other with the appropriate hinge.

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TECH FIG 3 • Technique of preparing the ulnar notch. A highspeed burr is recommended.

▪ Soft Tissue and Muscle Reconstruction The brachioradialis and extensor carpi radialis muscles are sutured to the remaining biceps and triceps muscles to secure soft tissue around the flared distal portion of the humeral endoprosthesis. A flexorplasty is performed. With the elbow held in 60 degrees of flexion and the forearm fully supinated, these muscles are transferred to as proximal a position as possible and sutured to the biceps muscle with no. 5 nonabsorbable sutures. The biceps is pulled distally and placed under tension while these muscles are sutured to it. This step is especially important if the prosthesis has been shortened because it restores the length-tension relation of the biceps muscle. The elbow is kept in 60 degrees of flexion and fully supinated for the remainder of the procedure. The origin of the flexor-pronator forearm muscles also is transferred as far proximal as possible and sutured to the medial border of the biceps and triceps muscles. At this time, for postoperative analgesia, an epidural catheter can be threaded proximally along the median nerve, deep to the vascular sheath, to a level where it can bathe the entire brachial plexus with bupivacaine. A drain is also placed at this time. The remaining muscles, usually the biceps-brachialis muscles and triceps muscles, are sutured to each other to close over the entire prosthesis and neurovascular structures (TECH FIG 4).

TECH FIG 4 • Soft tissue closure. A. It is important for the prosthesis to be completely covered by muscle. The flexors (from the medial condyle) and the brachioradialis (mobile wad of 3) from the lateral condyle are reattached to the adjacent soft tissue. It is not necessary to attempt reattachment to the prosthesis. B. Reattachment of the elbow flexors. An ulnar nerve transposition may be performed, although this is not done routinely. (continued) P.125

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TECH FIG 4 • (continued) C. The passive range of motion of the elbow is tested prior to closure. If there is any restriction, the radial head should be examined or removed. Sometimes, depending on the amount of soft tissue that is resected with the neoplasm, it is useful to shorten the prosthesis an additional 2 to 3 cm to facilitate soft tissue coverage. The biceps requires retensioning with sutures if this situation arises. Likewise, proximal transfer (ie, tensioning) of the brachioradialis and forearm flexor origins (ie, flexorplasty) is beneficial for restoring elbow flexion power.

PEARLS AND PITFALLS Evaluating intraosseous tumor extent

▪ T1-weighted MRI scans are the most accurate for determining intraosseous tumor extent. The T2-weighted image often is associated with significant peritumoral edema, which overestimates tumor extent.

Biopsy

▪ The biopsy should be taken through the brachialis muscle and in line with the proposed skin incision that would be used for definitive resection. The biceps must not be penetrated or contaminated. Preservation of the biceps muscle is crucial for restoring elbow flexion following reconstruction.

Neurovascular structures

▪ The major neurovascular structures are all identified in normal tissue proximal to the neoplasm along the medial side of the midarm. Dissection is initiated in a proximal to distal direction. All important structures (ie, brachial vessels, median nerve, ulnar nerve, and radial nerve) are identified, separated, and mobilized away from the neoplasm and distal humerus. Once all vital structures are preserved and protected, the resection can begin. Care is taken to

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preserve the nerve to the flexor digitorum superficialis when tumors of the flexor-pronator group are resected. Likewise, care is taken to preserve the branches of the posterior interosseous nerve when tumors of the brachioradialis and common extensor muscle group are resected. Skeletal/endoprosthetic reconstruction

▪ The endoprosthesis is downsized 2-3 cm to facilitate soft tissue coverage, if necessary. The elbow flexors are retensioned to accommodate for the shortening. The prosthesis is cemented so that the hinge faces anteriorly. The ulnar component must be seated as deep as possible within the olecranon.

Soft tissue reconstruction

▪ It is important to maintain the elbow in 60 degrees of flexion and fully supinated when performing the soft tissue reconstruction. Proximal transfer under tension of both the common extensor muscle origin and the flexor- pronator origin to either side of the biceps muscle accomplishes a flexorplasty of the elbow that assists with restoring elbow flexion power. It may be necessary to restore the length-tension relation of the biceps by pulling the biceps distally and suturing it to the forearm musculature under tension.

POSTOPERATIVE CARE Edema control is essential in the early postoperative period. Patients are covered from hand to shoulder with a bulky dressing and a splint that maintains the elbow in 60 degrees of flexion. Elastic bandages are applied for light compression. The extremity is elevated and the patient remains primarily at bed rest for 3 to 4 days. Drains and the perineural catheter are removed at this time. The dressings are changed approximately 4 days postoperatively, and the splint is reapplied to maintain the elbow in 60 degrees of flexion. The extremity is kept in a splint for a total of 6 weeks to allow for sufficient muscle healing and scarring. Elbow motion is prohibited for 6 weeks. Immediately after surgery, active and passive range of motion of the wrist, hand, and digits, along with hand strengthening, is initiated and continued for 6 weeks while the arm is in the splint. Hand and wrist strengthening is continued throughout the entire rehabilitation process. At 6 weeks, the patient is placed in a hinged elbow brace and permitted active, active assisted, and passive range of motion from 30 degrees of flexion to 130 degrees of flexion. The patient is not permitted to extend the elbow for the next 6 weeks past approximately 30 degrees of flexion. At 12 weeks after surgery, the brace is adjusted to allow full motion of the elbow. Strengthening of the elbow is initiated at this time, with a 2-pound weight limit. The brace is worn P.126 for 6 more weeks, usually until approximately week 18. The patient can wear a sling after week 18 when necessary for comfort. At week 18, resistance strengthening can be increased to a 5-pound weight limit if the patient is now able to handle 2 pounds. At 6 months after surgery, the weight limit for resistance strengthening is increased to 10 pounds. Patients are advised not to lift more than 10 pounds with the extremity.

OUTCOMES Oncologic results: Local recurrence is less than 5%. In our series of 16 patients, there was one local recurrence in a patient with a previous elbow arthroscopy. Prosthetic survival: In our small series of 16 patients, there was one instance of septic prosthetic loosening (FIG 3). Function: All patients are pain free and have stable elbows. Patients do not require a brace. Elbow, wrist, and hand function are virtually normal. All patients could flex their elbows up to 110 to 130 degrees, and it will depend of the biceps muscle continuity. In general, patients lacked 10 to 30 degrees of terminal extension. All patients could carry out activities of daily living. The Musculoskeletal Tumor Society score ranged from 24 to 27 of 30 possible points (80% to 90%). The main restrictions are in recreational http://e-surg.com

activities. Most patients can flex their elbows against 10 pounds of resistance.

FIG 3 • Postoperative radiograph showing the prosthesis and its components.

COMPLICATIONS The authors favor the use of the anterior approach of the elbow as a way to reduce the number of soft tissue and bone complications. Soft tissue flaps are possible to make with the anterior approach, and in all cases, a close without tension is doable. Transient nerve palsies (1 out of 16 patients); resolved within 6 months Skin necrosis and wound infections (1 out of 16 patients); resolved with débridement and closure Aseptic loosening (0 out of 16 patients) Septic loosening (1 out of 16 patients), prosthesis revision Local recurrence (1 out of 16 patients). In one instance, the axle broke and was replaced.

SUGGESTED READINGS 1. Malawer MM, Link M, Donaldson S. Sarcomas of bone. In: Devita VT, Hellman S, Rosenberg SA, eds. Cancer: Principles and Practice of Oncology, ed 3. Philadelphia: JB Lippincott; 1989. 2. Malawer MM, Sugarbaker PH, Lambert MH, et al. The Tikhoff-Linberg procedure and its modifications. In: Sugarbaker PH, ed. Atlas of Sarcoma Surgery. Philadelphia: JB Lippincott, 1984.

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Chapter 12 Surgical Management of Metastatic Bone Disease: Humeral Lesions Jacob Bickels Martin M. Malawer

BACKGROUND The humerus is a common site of metastatic bone disease requiring surgery. A metastasis at that site, and especially one involving the dominant extremity, has an immediate and profound impact on the affected individual's ability to perform activities of daily living. The quality of surgery, therefore, is an important determinant in restoring vital function. A detailed preoperative clinical and imaging evaluation is mandatory for defining the morphologic characteristics of the lesion and, in turn, establishing the indication for surgical intervention as well as distinguishing between lesions that can be managed with curettage and cemented fixation and those which require resection with endoprosthetic reconstruction.2,3,5,6 Unlike primary sarcomas of the humerus, metastatic tumors usually have a small soft tissue component, even in the presence of extensive bone destruction. This characteristic allows resection of bony elements only and the sparing of the extracortical structures, such as the joint capsule, overlying muscles, and muscle attachments, and affords the opportunity for using them to reconstruct and preserve function (FIG 1). To this end, exposure of the proximal humerus is done by splitting the deltoid muscle rather than using the deltopectoral interval, as is done in the case of a primary sarcoma of bone, which necessitates en bloc resection of the deltoid muscle with the tumor. Moreover, a few centimeters of upper limb shortening following resection of bone segment has minimal impact on function because a slight difference in positioning of that extremity in space can easily compensate for such limb length discrepancy.

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FIG 1 • A. Primary bone sarcomas usually have considerable extension into the soft tissues. Resection of such tumors at the proximal humerus would require en bloc removal of the overlying deltoid muscle, rotator cuff tendons, and the joint capsule. B. Bone metastases, however, usually present with less soft tissue involvement, and their resection involves removal of bony elements with only a thin layer of surrounding soft tissues. In contrast, a similar discrepancy in the lower extremities that require almost equal length for normal gait would result in an inevitable limp, the extent of which would be proportional to the shortening of the operated extremity.2 Because of different anatomic and surgical considerations, surgeries around the proximal humerus (type I), humeral diaphysis (type II), and distal humerus (type III) will be discussed separately (FIG 2).1

ANATOMY Proximal humerus: type I metastasis Covered anteriorly and laterally by the deltoid muscle Joint capsule encircles the humeral head and attaches to the base of anatomic neck. Attachment site for the rotator cuff muscles. Long head of the biceps muscle crosses the anterior aspect within the bicipital groove. Humeral diaphysis: type II metastasis http://e-surg.com

Upper half is occupied by muscle insertions: Medial aspect—teres major, latissimus dorsi, coracobrachialis Lateral aspect—pectoralis major, deltoid P.128

FIG 2 • Illustrations and plain radiographs showing a type I humeral metastasis (A,B) extending across the anatomic neck to the humeral head, a type II humeral metastasis (C,D) involving the humeral diaphysis between the anatomic neck and the supracondylar ridges of the humerus, and a type III humeral metastasis (E,F) extending to the humeral condyles below the supracondylar ridges. Radial nerve curves at the back from medial to lateral at the midarm level Lower half is occupied by muscle origins: Medial aspect—brachialis Lateral aspect—brachioradialis Neurovascular bundle along its medial aspect Distal humerus: type III metastasis Neurovascular bundle along its medial aspect between the biceps and brachialis muscles http://e-surg.com

Radial nerve along its lateral aspect between the brachialis and brachioradialis muscles

INDICATIONS Pathologic fracture Impending pathologic fracture Intractable pain associated with locally progressive disease that had shown inadequate response to narcotics and preoperative radiation therapy Solitary bone metastasis in selected patients

IMAGING AND OTHER STAGING STUDIES Plain radiographs of the entire humerus are mandatory to rule out synchronous metastases that may change the extent and technique of surgery. Computed tomography of the lesion will clearly define the extents of bone destruction and soft tissue component. Total body bone scintigraphy is done to detect synchronous metastases elsewhere in the skeleton. At the conclusion of imaging, the surgeon should be able to answer the following questions: Are there additional humeral metastases and, if there are, can they be managed by nonoperative techniques or do they require surgery? Are there additional skeletal metastases and, if there are, can they be managed by nonoperative techniques or do they require surgery? What is the appropriate surgery? As a rule, the tumor curettage and cemented fixation approach is used for lesions in which the remaining cortices allow containment of the fixation device; otherwise, surgery involves resection of the affected bone segment with prosthetic reconstruction. P.129

TECHNIQUES ▪ Types I and II Metastases Position and Incision The patient is placed in a semilateral position, and an anterior utilitarian shoulder girdle incision is made. The incision begins at the junction of the inner and middle third of the clavicle and continues over the coracoid process, along the deltopectoral groove, and down the arm over the medial border of the biceps muscle (TECH FIG 1).

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TECH FIG 1 • A,B. The utilitarian shoulder incision is used for exposure of types I and II metastases. It begins at the junction of the inner and middle third of the clavicle and continues over the coracoid process, along the deltopectoral groove, and down the arm over the medial border of the biceps muscle up to the distal arm, if required.

TECH FIG 2 • A,B. The deltoid and brachialis muscles are divided longitudinally to expose the humeral head and humeral diaphysis. The periosteum is similarly divided and reflected with muscle to expose the http://e-surg.com

underlying cortex. Exposure The deltoid muscle is divided longitudinally to expose the humeral head and proximal third of the humeral diaphysis. Exposure of the remaining diaphysis is achieved by similarly dividing the brachialis muscle. Electrocautery and rasps are used to detach and reflect the periosteum and muscle attachments from the underlying cortex (TECH FIG 2). P.130 Tumor Removal Type I Metastasis Using electrocautery, the rotator cuff tendons are detached from the humerus, the long head of the biceps is cut at its insertion site around the glenoid, and the joint capsule is opened. Osteotomy is carried out at the required level below the surgical neck, 1 to 2 cm below the distal margin of the tumor, and the proximal humerus can now be removed (TECH FIG 3). Type II Metastasis A longitudinal cortical window with oval edges is made just above the lesion (TECH FIG 4A). Gross tumor is removed with hand curettes (TECH FIG 4B,C). Curettage should be meticulous and leave only microscopic disease in the tumor cavity. It is followed by high-speed burr drilling of walls of the tumor cavity (TECH FIG 4D-F). Occasionally, the cortices of the involved segment are completely destroyed, leaving no option but an intercalary resection of the affected segment. This is achieved by an osteotomy 1 to 2 cm above and below the segment (TECH FIG 4G-I). Mechanical Reconstruction Type I Metastasis A cemented tumor prosthesis is used for reconstruction (TECH FIG 5). The prosthetic design should allow the reattachment of rotator cuff tendons.

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TECH FIG 3 • A-C. Resection of the type I metastatic renal cell carcinoma in the plain radiograph in FIG 2B is executed by detaching the rotator cuff tendons and the long head of the biceps and opening the joint capsule. An osteotomy is performed, and the proximal humeral segment is removed. D. Surgical specimen. Type II Metastasis An intramedullary nail is introduced. After proper position and length are verified, the nail is partially pulled back, and the entire tumor cavity is filled with cement (TECH FIG 6A,B). The nail is then pushed back into the medullary canal and fixed with interlocking screws. Alternatively, a side plate can be used for reinforcement (TECH FIG 6C,D). If an intercalary resection had been done, the remaining bone defect is filled with cement (TECH FIG 6EG). Soft Tissue Reconstruction and Wound Closure Type I Metastasis The rotator cuff tendons are attached to the prosthetic head using 3-mm Dacron tapes (Deknatel, Falls River, MA) or no. 5 Ethibond sutures (Ethicon, Somerville, NJ) (TECH FIG 7). The pectoralis major, teres major, latissimus dorsi, and coracobrachialis are similarly attached. Using the same technique, the prosthetic head is also secured to the drill holes within the bony elements around the shoulder joint, acromion, clavicle, and glenoid. The second, overlying muscular layer includes the deltoid and brachialis muscles, which are sutured to cover the implant. Type II Metastasis http://e-surg.com

The deltoid and brachialis muscles are sutured to cover the humeral diaphysis. P.131

TECH FIG 4 • A. A longitudinal cortical window with oval edges is made just above the lesion. B,C. Gross tumor is removed with hand curettes. Curettage should be meticulous and leave only microscopic disease in the tumor cavity. (continued) P.132

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TECH FIG 4 • (continued) D,E. Curettage is followed by high-speed burr drilling of walls of the tumor cavity. F. Tumor cavity following curettage and burr drilling G. Plain radiograph of type II thyroid carcinoma metastases. The extent of cortical destruction does not allow curettage and burr drilling and so intercalary resection of the affected segment is indicated. H-I. Intercalary resection is achieved by proximal and distal osteotomies 1 to 2 cm above and below the tumor margin. P.133

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TECH FIG 5 • Intraoperative photograph (A) and plain radiograph (B) showing a proximal humeral tumor prosthesis used for reconstruction after resection of a type I metastasis.

TECH FIG 6 • A. An intramedullary nail is introduced. B. After proper position and length are verified, the nail is partially pulled back, and the entire tumor cavity is filled with cement. The nail is then pushed back into the medullary canal and fixed with interlocking screws. Intraoperative photograph (C) and plain http://e-surg.com

radiograph (D) showing side plate reinforcement of a cemented intramedullary humeral nail. Intraoperative photographs (E,F) and plain radiograph (G) showing side plate reinforcement of a cemented intramedullary humeral nail following intercalary resection of a type II metastasis. The remaining bone defect is filled with cement. (continued) P.134

TECH FIG 6 • (continued)

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TECH FIG 7 • A. Three-millimeter Dacron tapes or (B) no. 5 Ethibond sutures are used for securing the prosthetic head to the neighboring acromion, clavicle, and glenoid and for reattachment of the rotator cuff tendons. C. Rotator cuff tendons are sutured to the prosthetic head. P.135

▪ Type III Metastasis These tumors extend to the humeral condyles below the supracondylar ridges. In most of these cases, the extent of bone destruction allows tumor curettage and reconstruction with cemented hardware (the technique will be described in the following section). Rarely will extensive destruction of the distal humerus necessitate formal resection with endoprosthetic reconstruction. Position and Incision The patient is placed supine on the operating table with the ipsilateral arm lying across the chest. A slightly curved incision is made on the lateral aspect of the arm over the supracondylar ridge of the elbow (TECH FIG 8). http://e-surg.com

TECH FIG 8 • To expose a lesion at the distal humerus, the patient is placed supine on the operating table with the ipsilateral arm lying across the chest. A slightly curved incision is made on the lateral aspect of the arm over the supracondylar ridge of the elbow.

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TECH FIG 9 • The distal humerus and radial head are exposed using the plane between the brachioradialis and triceps muscles.

TECH FIG 10 • A. Gross tumor is removed with hand curettes. B. Curettage is followed by high-speed burr drilling. Exposure The distal humerus is exposed using the plane between the brachioradialis and triceps muscles. The brachioradialis is reflected anteriorly and the triceps posteriorly. Further posterior reflection of the anconeus muscle combined with detachment and anterior reflection of the common extensor origin exposes the radial head (TECH FIG 9). Tumor Removal http://e-surg.com

A longitudinal cortical window with oval edges is made just above the lesion. Gross tumor is removed with hand curettes (TECH FIG 10A), and this is followed by high-speed burr drilling (TECH FIG 10B). P.136 Mechanical Reconstruction An intramedullary rod is introduced through the tumor cavity, which is then filled with cement. A reconstruction plate along the lateral supracondylar ridge is used to reinforce the reconstruction (TECH FIG 11).

TECH FIG 11 • A cemented intramedullary rod that is reinforced by a reconstruction plate along the supracondylar ridge is used for reconstruction. Wound Closure The wound is closed over suction drains. Continuous suction is required for 3 to 5 days, and perioperative intravenous antibiotics are continued until the drainage tubes are removed. http://e-surg.com

PEARLS AND PITFALLS Type II metastasis

▪

Adequate imaging of the entire humerus—decision on tumor curettage, intercalary resection, or resection with endoprosthetic reconstruction

▪

Use the utilitarian shoulder incision.

▪

Wide exposure of the tumor cavity using properly positioned and large cortical window

▪

Meticulous curettage and burr drilling

▪

Reconstruction with cemented hardware

▪

If endoprosthetic reconstruction was done ▪ Secure the prosthetic head to the surrounding bony elements to ensure shoulder stability. ▪ Reattach the rotator cuff tendons to the prosthetic head to allow shoulder function. ▪ Immobilize the shoulder for 3 weeks and only then allow ROM exercises.

Type III metastasis

▪

Adequate exposure of the distal humerus

▪

Meticulous curettage and burr drilling

▪

Reconstruction with cemented hardware

▪

Early postoperative mobilization of the elbow joint

POSTOPERATIVE CARE AND REHABILITATION Types I and II Metastases Continuous suction is required for 3 to 5 days, and perioperative intravenous antibiotics are continued until the drainage tubes are removed. If endoprosthetic reconstruction had been done, the shoulder is immobilized in a sling for 3 weeks. During that time, the rehabilitation program emphasizes range of motion (ROM) of the elbow, wrist, and fingers with gravity assistance. Gradual passive and active ROM of the shoulder is then started, with emphasis on forward flexion, abduction, and shrugging. If tumor curettage had been carried out, ROM exercises should be practiced without delay. Upon wound healing, usually 3 to 4 weeks after surgery, patients are referred to adjuvant radiation therapy. Radiation therapy is usually not required in patients who had undergone proximal humerus resection with endoprosthetic reconstruction. P.137

Type III Metastasis Passive and active ROM exercises of the elbow joint are initiated when the suction drains are removed. Upon wound healing, usually 3 to 4 weeks after surgery, the patients are referred to adjuvant radiation therapy. Radiation therapy is usually not required for patients who had undergone distal humerus resection with endoprosthetic reconstruction. http://e-surg.com

OUTCOMES Most patients who undergo resection of a humeral metastasis experience immediate relief of their metastasis-related pain. Patients who had a type II metastasis and who underwent either curettage or intercalary resection have better ROMs and superior functional outcome than the ones who underwent proximal or distal humeral resection with endoprosthetic reconstruction. Bickels et al2 reported that overall total function in their 56 patients (95%) who had undergone resection of a humeral metastasis was greater than 68% of full normal upper extremity function, which is the mean functional outcome score after reconstruction of the upper extremity.4

COMPLICATIONS Thromboembolic complications, deep wound infections, and prosthetic loosening (rare) Proximal humeral prosthetic dislocation (poor securing to the adjacent bones and inadequate soft tissue coverage) Decreased ROM around the shoulder (poor attachment of the rotator cuff tendons to the prosthesis) Decreased elbow ROM after surgery around distal humerus lesions Local tumor recurrence of less than 5% if adjuvant tumor removal was done adequately and adjuvant radiation therapy had been administered.

REFERENCES 1. Bickels J, Kollender Y, Wittig JC, et al. Function after resection of humeral metastases. Analysis of 59 consecutive patients. Clin Orthop Relat Res 2005;137:201-208. 2. Bickels J, Wittig JC, Kollender Y, et al. Limb-sparing resections of the shoulder girdle. J Am Coll Surg 2002;194:422-435. 3. Eckardt JJ, Kabo JM, Kelly CM, et al. Endoprosthetic reconstructions for bone metastases. Clin Orthop Relat Res 2003;415(suppl):s254-s262. 4. Enneking WF, Dunham W, Gebhardt MC, et al. A system for functional evaluation of reconstructive procedures after surgical treatment of tumors of the musculoskeletal system. Clin Orthop Relat Res 1993;286:241-246. 5. Flemming JE, Beals RK. Pathologic fractures of the humerus. Clin Orthop 1986;203:258-260. 6. Harrington KD, Sim FH, Enis JE, et al. Methylmethacrylate as an adjuvant in internal fixation of pathological fractures: experience with three hundred and seventy-five cases. J Bone Joint Surg 1976;58A:1047-1055.

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Chapter 13 Axillary Space Exploration and Resections James C. Wittig Martin M. Malawer Kristen Kellar-Graney

BACKGROUND The axilla is a common site for primary soft tissue sarcomas as well as for metastatic disease that involves the axillary lymph nodes, such as advanced breast cancer or melanoma. Sarcomas typically arise from the muscles defining the axillary space (FIG 1). Occasionally, however, they may arise directly from the brachial plexus or axillary vessels (eg, malignant peripheral nerve sheath tumors, neurosarcoma, leiomyosarcoma). Several types of malignant tumors may involve the axillary space and may require surgical resection. Primary sarcomas occur within the muscles (ie, the pectoralis major, latissimus dorsi, teres major, and subscapularis muscles) that make up the borders of the axillary space. Rarely do they develop within the axillary fat itself. More commonly, large metastatic deposits to the regional lymph nodes create large, matted masses that may require resection. The most common of these are metastatic melanoma and recurrent breast carcinoma. In addition, there are primary tumors that arise from the brachial plexus, either the nerves or the vessels. These include leiomyosarcomas of the axillary vein and neurofibrosarcomas of the adjacent nerves.

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FIG 1 • Anatomy of the axillary space. A. Schematic of the shoulder girdle and axilla showing the bony and soft tissue contents. The axillary artery enters from the clavicle and exits at the lower portion of the axilla at the level of the pectoralis major and latissimus dorsi muscles. The overlying pectoralis major muscle forming the anterior wall and the latissimus dorsi muscle forming the posterior wall is visualized. B. MRI scan of a normal axilla. All of the muscles of the anterior and posterior wall as well as the deltoid are shown. Small masses may be clinically silent, but large masses inevitably will result in significant pain or loss of function due to involvement of the brachial plexus. Venous occlusion may be seen in neglected, massive tumors and is a harbinger of loss of limb and possibly even of life due to gangrene. Historically, surgical management of tumors in this location consisted of forequarter amputation; advances in radiographic imaging, adjuvant therapies, and surgical techniques have greatly improved our ability to perform limb-sparing resections in this location.4 The key to adequate and safe surgical resection of axillary tumors is the complete visualization and mobilization of the infraclavicular portion of the brachial plexus and the axillary http://e-surg.com

artery and vein and the cords that surround them.1,2 In general, imaging studies of the axillary space are not reliable for determining vascular or nerve sheath involvement. Multiple imaging studies are required, but the ultimate decision to proceed with a limbsparing surgery is based on the intraoperative findings at the time of exploration.1,2,4,5 Axillary tumors extending along the chest wall often can be elevated off the underlying ribs; however, tumor extension into the intercostal spaces may require thoracotomy and rib resection to ensure adequate margins.

ANATOMY The axilla is a pyramid-shaped space between the chest wall and the arm defined by its surrounding muscles; it appears triangular when seen from either the coronal or axial views. The superior apex of the pyramid is formed by the junction of the clavicle and the first rib, approximately 1 to 2 cm medial to the coracoid process. The muscular boundaries of the axilla consist of the pectoralis major muscle anteriorly; the subscapularis, teres major, and latissimus dorsi muscles posteriorly; and the coracobrachialis, short head of the biceps, and triceps muscles laterally. Vital structures in the axilla include the major branches of the infraclavicular portion of the brachial plexus and the P.139 axillary vessels. Any surgery in this region requires detailed knowledge of and familiarity with these structures. Infraclavicular brachial plexus The lateral, posterior, and medial cords of the infraclavicular brachial plexus are found at the level of the pectoralis minor muscle, where they then give rise to five major branches: the median, ulnar, radial, musculocutaneous, and axillary nerves. The cords and branches run along the axillary vascular sheath as it passes through the axilla. The lateral cord gives rise to the musculocutaneous nerve, which travels along the medial aspect of the conjoint tendon, where it innervates the coracobrachialis and short head of the biceps. This nerve is the first to be identified during the exploration because it is located in the superficial axillary fat inferior to the coracoid process. The largest portion of the lateral cord combines with the medial cord to create the median nerve. The posterior cord gives rise to the axillary nerve, which travels deep in the space and passes inferior to the glenohumeral joint and subscapularis muscle, where it innervates the deltoid muscle. The main portion of the posterior cord becomes the radial nerve, which travels posterior to the sheath and exits the axillary space along with the axillary sheath. The medial cord gives rise to the ulnar nerve, which travels along the most medial aspect of the sheath and exits distally along with the sheath. Because of its medial position along the sheath, the ulnar nerve is the nerve most commonly involved by tumors arising inferior to the brachial plexus, which can present with symptoms of either weakness or neuropathic pain. The median nerve, formed by a combination of the lateral and medial cords, is found on the lateral aspect of the sheath and exits the inferior aspect of the axillary space along the sheath. Axillary vessels The axillary artery and vein are the continuation of the subclavian vessels, changing name as they enter the apex of the axilla below the clavicle and first rib. These vessels run in a single sheath, surrounded by the http://e-surg.com

cords of the brachial plexus. The vessels pass through the axillary space medial to the coracoid to the medial aspect along the humeral shaft. Distal to the teres major, the vessels are renamed the brachial vessels. Major vascular branches in the axillary space include the thoracoacromial artery (with its pectoral, deltoid, clavicular, and acromial branches), the lateral thoracic artery, the subscapular artery, and the anterior and posterior humeral circumflex vessels. Lymphatics A substantial amount of fat surrounds the vascular sheath as it runs through the axilla along with the lymphatics and lymph nodes. Major clusters of lymph nodes are found along the brachial and axillary vessels, the lateral thoracic vessels (anterior axillary nodes), and the subscapular vessels (posterior axillary nodes). Axillary tumors may arise from lymph node metastases anywhere along the axillary vessels; the most common sites are nodes along the distal portion of the axillary vessels.

INDICATIONS Any mass in the axillary space should be considered for biopsy or resection given the propensity for malignant tumors to develop in the axilla and the predictability of neurogenic pain arising from continued tumor growth. Palpate radial and ulnar pulses and inspect for venous congestion or swelling. Consider venography to evaluate loss of venous drainage indicative of tumor involving the brachial plexus. Diminution of arterial flow is a late sign indicative of potential loss of limb—consider forequarter amputation. Test sensation and strength of the axillary, radial, median, and ulnar nerves. Loss of nerve function typically is a very late finding indicative of major tumor involvement of the brachial plexus—consider forequarter amputation. Infraclavicular brachial plexus and vascular exploration is mandatory before resection is attempted. Tumor involvement of these structures usually indicates that a forequarter amputation is required.4

IMAGING AND OTHER STAGING STUDIES Three-dimensional imaging of the axillary space is important for accurate anatomic tumor localization and surgical planning. Computed tomography (CT), magnetic resonance imaging (MRI), angiography, and threephase bone scans are used in the same manner as in other anatomic sites. In addition, we have found that venography (of the axillary and brachial veins) is essential to the evaluation of tumors of the axilla and brachial plexus in patients where the decision regarding limb-sparing surgery is conflictive.8

Plain Radiography Careful inspection of posterior-anterior chest, anterior shoulder, and axillary view radiographs may reveal the presence of increased soft tissue density corresponding to an axillary mass. Bone involvement and the presence of calcifications in the soft tissues should be noted.

Computed Tomography and Magnetic Resonance Imaging Multiplanar MRI is extremely helpful in visualizing the anatomic contents of the axillary space and defining the anatomic extent of the tumor (FIG 2A-C). http://e-surg.com

Axial CT imaging, with administration of intravenous (IV) contrast, demonstrates the major vascular structures, outlines the major muscle planes, and can detect subtle matrix formation within the tumor. CT is most useful in evaluating the bony walls of the axilla, specifically the humerus, glenohumeral joint, and scapula (FIG 2D). Certain tumors, such as lipomas or hemangiomas, may have characteristic findings on T1- and T2-weighted MRI sequences suggestive of the proper histologic diagnosis. The presence or absence of lymphatic involvement should be noted, particularly in patients with a history of metastatic carcinoma. Although the brachial plexus may be difficult to visualize, particularly when tumors distort or compress the surrounding fatty planes, the anatomic relationship of the nerve sheath to the vessels helps pinpoint their location. Although CT imaging of the lungs is routinely performed as part of patient staging, the chest wall should always be inspected carefully to rule out tumor involvement of the rib cage and pleural cavity.

Nuclear Imaging Positron emission tomography (PET) imaging, particularly when fused with MRI or CT imaging data, may significantly P.140 improve the ability to detect lymphatic spread of tumor in and around the axilla. Standardized uptake values (SUV) correlate with tumor metabolism and may help to distinguish between benign and malignant lesions.

FIG 2 • Imaging studies of the axillary space. A. T2-weighted MRI scan showing a large mass (arrow) occupying the axillary space. B. Coronal T2-weighted MRI scan showing a large tumor below the pectoralis major that fills the entire axillary space, from the clavicle to the lower end of the base of the pyramid that forms the axillary http://e-surg.com

space. C. Axial MRI scan of a large fungating tumor from the axillary space. There are no muscle or skin components adjacent to the tumor, which protrudes anteriorly. D. CT scan of a primary bony sarcoma with a large extraosseous component that extends into the axilla. This finding is an excellent indication for the use of the anterior portion of the utilitarian incision for resections of large tumors of the proximal humerus. It demonstrates that the axillary space must be completely visualized and that the vessels must be mobilized.

Angiography and Other Studies Angiography remains a valuable method of imaging the axilla, particularly for preoperative planning, because tumors may significantly distort the regional vascular anatomy through mass effect as well as through angiogenesis (ie, formation of abnormal vessels feeding the tumor; FIG 3). Venography, either alone or in conjunction with angiography, can demonstrate venous compression from surrounding tumors. The axillary arterial wall is thick and rarely shows signs of occlusion, whereas the axillary vein is a thin-walled structure that is easily compressed and infiltrated by tumor. Therefore, occlusion is almost synonymous with involvement of the vascular sheath and brachial plexus. Venous occlusion, visualized as absent filling of the axillary vein, is characteristic of significant tumor involvement of the brachial plexus and warrants careful thought whether a limb-sparing procedure is possible. The triad of axillary venous occlusion, distal motor weakness, and neuropathic pain is a very reliable predictor of tumor infiltration of the brachial plexus sheath.

Biopsy Core needle biopsy is the preferred method of diagnosis because it minimizes risk of injury and contamination of the axillary contents. If a metastatic lesion is suspected, fine needle aspiration is the most appropriate means to identify carcinoma cells. Large or superficial palpable masses are amenable to needle biopsy in the clinic, whereas deep lesions are best approached with radiographic guidance using CT or ultrasound. The biopsy tract should be positioned after consultation with the treating surgeon to ensure proper location along the path of planned resection. The biopsy should be performed through the base of the axillary space, not through the pectoralis major muscle or near the vascular sheath. It can easily be performed under CT guidance. Deep-seated lesions near the chest wall also can be approached in this manner. Anterior lesions, on occasion, can be approached through the lower portion of the pectoralis major muscle. The biopsy site must be removed in its entirety during resection of the tumor. Open biopsy should be reserved for those patients in whom core needle biopsy was nondiagnostic or in those cases when additional samples of tumor are necessary for research purposes. Great care must be taken to avoid contamination of critical structures and otherwise uninvolved tissue planes. A small laterally placed incision, avoiding the pectoralis major muscle and the axillary sheath, is recommended. Although small tumors are amenable to excisional biopsy, care must be taken to remove the entire pseudocapsule in the event that the tumor is found to be a sarcoma.

SURGICAL MANAGEMENT Although many patients can safely undergo limb-sparing resections of the axillary space, extremely large or neglected tumors may present with significant involvement of the axillary vessels and brachial plexus. Evidence of vascular involvement and, therefore, nerve sheath invasion should raise the question whether the patient is suitable for a limb-sparing resection; forequarter amputation may be necessary. Proper placement of the biopsy tract is critical in limiting potential injury or contamination of the axillary space; http://e-surg.com

large, poorly planned open biopsy tracts may necessitate forequarter amputation. Adjuvant radiation to the axilla carries an increased risk of significant lymphedema, which can be functionally disabling, as well as potential wound complications, which increase the level of difficulty of the procedure. P.141

FIG 3 • Schematic representation of an axillary tumor with its relationship to the axillary sheath. A. The tumor does not involve the sheath but it displaces the artery, vein, and accompanying nerves. B. The tumor has invaded the axillary sheath, occluding the axillary vein. This is a significant finding on venography that almost always indicates vascular infiltration. C. Axillary venogram performed and shows complete occlusion of the axillary vein (red line). Collateral filling is seen around the mass. Obliteration of the vein almost always indicates infiltration of the infraclavicular plexus. D. Gross specimen following forequarter amputation showing tumor infiltration around the nerves and cords of the brachial plexus and surrounding the axillary artery and vein.

Preoperative Planning Careful review of preoperative imaging studies is necessary to formulate a surgical plan. Extent of resection is determined by tumor size and stage and whether a palliative or curative option exists. Consideration should be given to preoperative angiography or venography when vascular involvement is suspected on the basis of CT or MRI scans. A double-lumen endotracheal tube should be used whenever preoperative imaging suggests significant rib involvement. Deflation of the underlying lung protects the lung during the rib resection.

Positioning Positioning of the patient for axillary resection is determined by the size and anatomic extent of the tumor to be removed. Most axillary tumors are best approached via an extensile anterior incision with the patient in the supine http://e-surg.com

position. The patient is brought to the edge of the table, and a large padded bump is placed under the medial portion of the scapula to facilitate exposure. After prepping and draping the arm, axilla, and anterior shoulder girdle, the arm is placed over a padded Mayo stand, and the surgeon stands inside the axilla for the procedure. The surgical assistant is best placed superior to the arm to facilitate retraction Less commonly, the posterior or inferior portion of the axilla is involved, requiring access to the back of the axilla and shoulder girdle. When this is the case, the patient should be placed in the lateral decubitus position so that the entire shoulder girdle may be easily accessed. The arm is elevated over the patient's head and supported by an assistant to permit access to the axilla. The surgeon should stand anterior to the patient, closest to the brachial plexus.

Approach Anterior/medial utilitarian approach. The most commonly used approach for axillary resections is the common extensile approach to the shoulder girdle and arm, running along the deltopectoral groove. As the pectoralis major comprises the anterior anatomic boundary of the axilla, release of its broad tendon insertion into the humerus is vital to proper exposure of the axillary contents (FIG 4). The traditional incision along the inferior boundary of the axilla offers a very limited view of the axillary contents and makes identification of the brachial plexus difficult. This incision is best used only for patients with tumor limited to the chest wall (inferior axillary resection) or posterior (latissimus) axilla. A combination of the traditional axillary incision with the anterior extensile incision may be performed by extending the skin incision across the pectoralis muscle, meeting the anterior incision near the coracoid process (FIG 5). This is useful in the salvage of patients having attempted resections or open biopsies through the inferior axilla. P.142

FIG 4 • Incisions. A. The typical axillary incision, used primarily by general surgeons for lymph node dissection. This incision is inadequate for resections of sarcomas or large bulky tumor masses. B. Anterior portion of the utilitarian shoulder girdle incision. This is used for large axillary tumors. A large mass was palpated (T). By detaching the pectoralis major, the entire axillary space can be visualized. C. A patient with a large metastatic lesion arising from the coracoid. The anterior portion of the utilitarian shoulder girdle incision is used to mobilize the axillary vessels prior to resection of the tumor. D. Operative photograph showing release and medial retraction of the pectoralis major muscle. The fascia covering the entire axillary space contents is seen (arrow). http://e-surg.com

FIG 5 • Surgical technique of exposure and resection of axillary tumors. A. The anterior portion of the utilitarian shoulder girdle incision is used. This is an extended deltopectoral incision, which may be curved in a posterior direction toward the axilla. The pectoralis major is then released 1 cm from its insertion onto the humerus. This is the first layer of axillary space musculature. B. Operative photograph showing the second muscle layer. The short head of the biceps and the pectoralis minor attach to the coracoid. The axillary contents with the vessels and nerves are not seen because they are enclosed within the axillary fat and fascia. C. The musculocutaneous nerve is found 1 to 2 cm distal to the coracoid, below the insertion of the pectoralis minor and adjacent to the short head of the biceps. This nerve must be identified before the second layer of muscles is released. (continued) P.143

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FIG 5 • (continued) D,E. Resection bed following removal of the tumor of the axillary space. It is necessary to begin at the level of the clavicle and ligate all branches that pass distal and inferior to the tumor mass. Most tumors arise inferior to the neurovascular bundle.

TECHNIQUES ▪ Axillary Exploration through Anterior Approach Exposure Palpate and mark the bony landmarks: coracoid process, acromion, acromioclavicular joint. Palpate the groove between the deltoid and pectoralis muscles. The skin incision should extend along the deltopectoral groove to the coracoid process and may curve into the axilla as needed. Open this interval, sparing or ligating the cephalic vein as necessary. Identify the pectoralis major insertion into the humeral shaft and release using the electrocautery approximately 1 cm from the bone to preserve enough insertion for later repair (TECH FIG 1). After the pectoralis major is fully released from the humerus, retract the muscle medially over the anterior chest wall, preserving its vascular pedicles and exposing the serratus anterior. Develop the anterior axillary fascial plane along the clavipectoral fascia, which is a thick, well-defined layer that contains the axillary space and structures. Palpate the conjoint tendon insertion at the coracoid process and release. Protect the musculocutaneous nerve inserting into the muscle belly just distal to the tendon from the underlying brachial plexus by limiting distal retraction. http://e-surg.com

Release of these muscles is key to exposing the vascular sheath and brachial plexus. Neurologic and Vascular Exploration Identify the sheath of the brachial plexus and axillary vessels underneath the detached conjoint tendon. The musculocutaneous nerve comes around the lower border of the coracoid under the pectoralis minor muscle. The axillary nerve comes off deeper from the posterior cord and travels toward the shoulder joint. Both must be identified at this stage. Completely expose and control the axillary vessels and brachial plexus proximally by opening the pedicle sheath and placing loops around the major structures; careful dissection is then used to mobilize these structures distally into the arm. Mobilization often is necessary to facilitate adequate exposure prior to tumor resection. Tumor Resection All of the feeding branches entering into the mass are serially ligated and transected.1,2 Axillary fat is left around the tumor mass as the only true margin. The tumor is removed, tagged for orientation, and sent to pathology for margins and histologic evaluation. P.144

TECH FIG 1 • A. Schematic diagram of the muscles of the anterior aspect of the axillary space being released to expose a large underlying axillary tumor. Two layers of muscles are encountered: the pectoralis major muscle and the pectoralis minor with the short head of the biceps. Both layers attach to the coracoid. The musculocutaneous nerve must be mobilized before the second layer of muscle is detached. B. Operative photograph taken following removal of a large axillary tumor shows all of the muscles of the axillary space, the axillary sheath, and corresponding cords of the brachial plexus.

▪ Resection of Anterior Axillary and Chest Wall Tumors Tumors involving the pectoralis and serratus anterior can be resected safely following identification and mobilization of the critical neurovascular structures; these muscles may be elevated directly off the underlying chest wall. Resection of high-grade sarcomas may require sacrifice of one or more major branches of the brachial plexus to achieve an adequate oncologic margin. Loss of the median nerve results in the greatest loss of hand function. http://e-surg.com

Chest wall involvement requires thoracotomy and resection of contiguous ribs; the underlying lung is deflated before opening the chest cavity to protect it. Intrathoracic extent of tumor is determined by palpation of the pleural surface following thoracotomy; osteotomy of the ribs using a rib cutter under direct visualization permits en bloc removal of the involved chest wall. Lymphatic involvement, frequently seen in patients with breast cancer extending into the axilla, requires meticulous dissection of the axillary and subclavian vessels proximally; sampling of lymph nodes is crucial in patients with carcinomas or melanoma.

▪ Resection of Posterior Axillary Tumors Further exposure of the axilla is achieved by extending the vascular and neurologic exploration further down the arm, widening the area to reach posterior or distal tumors (TECH FIG 2). Identify the latissimus insertion into the humerus, which defines the posterior aspect of the axilla distal and posterior to the pectoralis insertion. Before performing tendon release, identify and protect the axillary nerve proximal to and the radial nerve distal to the tendon; both nerves serve to tether the brachial plexus and reduce the ability to retract the plexus. Tumor involvement of the latissimus may require sacrifice of one or both of these nerves. The latissimus muscle may be elevated off the chest wall as necessary for tumor resection. Chest wall involvement may require thoracotomy and resection of contiguous ribs; deflate the lung before opening the chest cavity to protect the underlying lung. Intrathoracic extent of tumor may be determined by palpation of the pleural surface following thoracotomy. Osteotomy of the ribs using a rib cutter under direct visualization permits en bloc removal of the involved chest wall. P.145

TECH FIG 2 • A. Extremely large, low-grade, fibrosarcoma of the axilla extending from the thoracic outlet to the posterior axillary line and to the level of the breast (arrow). All tissues were removed through a combination of the anterior and posterior portions of the utilitarian shoulder girdle incision. B. Intraoperative photograph taken before reconstruction and reattachment of the muscles of the back and anterior pectoralis major. This photograph demonstrates the advantage of a transpectoralis approach anteriorly combined with a posterior approach.

▪ Reconstruction following Tumor Resection http://e-surg.com

Repair and reconstruction of the axilla is necessary following tumor resection. Insertion of an epineural catheter into the sheath of the brachial plexus permits postoperative administration of local anesthetics such as bupivacaine (Marcaine) to minimize postoperative pain. Reattachment of the conjoint tendon and pectoralis minor to the coracoid with the use of mattressed, nonabsorbable sutures covers the brachial plexus and axillary vessels. Defects of the chest wall can be covered with local rotation flaps using the latissimus dorsi or pectoralis major muscle, which may be tenodesed to the subscapularis tendon as needed.3 Careful wound closure over closed suction drains and placement of absorptive padding in the axilla reduce the risk of skin maceration and wound infection. Use of a sling or shoulder immobilizer permits early mobilization of the patient. Functional deficits resulting from resection of portions of the brachial plexus may require delayed reconstruction after completion of adjuvant treatment.

PEARLS AND PITFALLS Preoperative angiogram and venogram

▪ In addition to mapping out the course of the vessels, loss of flow through the brachial or axillary vein is a worrisome sign that tumor involves the brachial sheath. This often is the first sign of an unresectable tumor (FIG 6) for which forequarter amputation should be considered.

FIG 6 • Unresectable sarcoma of the axilla. A. Multiple recurrences with a large soft tissue mass. B. Operative view through the anterior incision showing a large tumor surrounding the axillary sheath. Axillary incision

▪ The axillary incision is not easily extended and severely restricts the ability to dissect out the neurovascular bundle. This incision is rarely indicated.

Pectoralis major

▪ Detachment of the humeral insertion is key to opening up the entire axilla and permits exploration of all important structures. It is not necessary to reattach the pectoralis to its insertion; rotation of this muscle is valuable for reconstruction of defects around the shoulder.

Musculocutaneous nerve

▪ Injury due to overretraction of the conjoint tendon may occur, leading to loss of elbow flexion and resulting disability. This may be unavoidable for tumors involving the conjoint tendon.

P.146

POSTOPERATIVE CARE Postoperatively, a sling or shoulder immobilizer is applied to support the arm. Closed suction drains are removed after output slows. http://e-surg.com

Patients are mobilized on postoperative day 1 from bed to chair. Ambulation is begun as tolerated to improve pulmonary function. A sling is used until the skin wound is sufficiently healed. Early shoulder motion with assistance is started as soon as the wound permits. Aggressive wrapping of the arm and use of customfitted compression gloves is started if there is evidence of lymphedema.

OUTCOMES Oncologic outcomes are similar with soft tissue tumor resection in other localization. The main consideration in the preoperative plan is the chest wall compromise or neurovascular infiltration. Both of these circumstances make impossible a limb-sparing surgery in the majority of the cases.7 Functional outcome is determined by the amount of muscle resection, loss of particular nerves, and the use of pre-/postoperative radiotherapy.6 Loss of shoulder motion results in mild disability, which is easily compensated for by use of the other arm for overhead activities. The range of motion (ROM) and functional parameters are satisfactory in the majority of patients after the tumoral resection around the axilla. Prompt rehabilitation is directly related with the final ROM and function.2,6

COMPLICATIONS Although uncommon, the complication most often seen following axillary resection is the accumulation of third-space fluid with secondary wound problems. Previous radiation therapy increases this probability. Use of suction drains and compressive dressings helps mitigate this complication. Nerve palsies are not frequent in axillary tumor resection, and when they are present, the majority of the cases resolve 6 months postoperatively. Traction and manipulation in the surgery and swelling after explain this low percentage of nerve complications. Chronic pain may occur following nerve resection, especially after radiation. Use of nerve sheath catheters with postoperative infusion of local anesthetics may reduce the incidence of neuropathic pain and helps with the prompt rehabilitation. Lymphedema may result in significant disability and chronic pain; early aggressive treatment may lessen the severity or duration of swelling. The risk is greatest following surgery and radiation therapy. Infections and flap necrosis following axillary tumor resections rarely occur because of the substantial network of subcutaneous blood vessels perfusing the shoulder girdle.

REFERENCES 1. Kim JY, Subramanian V, Yousef A, et al. Upper extremity limb salvage with microvascular reconstruction in patients with advanced sarcoma. Plast Reconstr Surg 2004;114:400-408. http://e-surg.com

2. Kim JY, Youssef A, Subramanian V, et al. Upper extremity reconstruction following resection of soft tissue sarcomas: a functional outcomes analysis. Ann Surg Oncol 2004;11:921-927. 3. Lohman RF, Nabawi AS, Reece GP, et al. Soft tissue sarcoma of the upper extremity: a 5-year experience at two institutions emphasizing the role of soft tissue flap reconstruction. Cancer 2002;94:2256-2264. 4. Maman E, Malawer MM, Kollender Y, et al. Large tumors of the axilla: limb-sparing resection versus amputation in 27 patients. Clin Orthop Relat Res 2007;461:189-196. 5. Murray PM. Soft tissue sarcoma of the upper extremity. Hand Clin 2004;20:325-333. 6. Nelson AA, Frassica FJ, Gordon TA, et al. Cost analysis of functional restoration surgery for extremity softtissue sarcoma. Plast Reconstr Surg 2006;117:277-283. 7. Popov P, Tukiainen E, Asko-Seljavaara S, et al. Soft-tissue sarcomas of the upper extremity: surgical treatment and outcome. Plast Reconstr Surg 2004;113:222-230. 8. Toomayan GA, Robertson F, Major N, et al. Upper extremity compartmental anatomy: clinical relevance to radiologists. Skeletal Radiol 2006;35:195-201.

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Chapter 14 Forequarter Amputation Jacob Bickels Yehuda Kollender Martin M. Malawer

BACKGROUND Forequarter amputation (interscapulothoracic amputation) entails en bloc removal of the upper extremity together with the scapula and the lateral aspect of the clavicle (FIG 1). This mutilating amputation of the upper extremity was traditionally done for high-grade sarcomas around the proximal humerus and scapula.1,3,6,7,8,9 Tumor response to chemotherapy and radiation therapy and the option of endoprosthetic reconstruction have made these procedures rare, and limb-sparing resections are safe alternatives in 90% to 95% of these cases.2

ANATOMY The upper extremity and scapula are attached to the upper torso and chest wall by soft tissue elements (rhomboid, levator scapulae, trapezius, pectoralis major and minor, latissimus dorsi, teres major, and serratus anterior muscles) and a single bone (clavicle). They all must be transected to allow the performance of a forequarter amputation. The axillary vessels and infraclavicular portion of the brachial plexus pass just inferiorly to the coracoid process, which is easily palpable, and lie below the deltopectoral fascia. These structures should be evaluated prior to surgery in order to determine the segment that can be safely transected and ligated, especially because large tumors may come close to the thoracic outlet. Large tumors of the periscapular area may easily extend into the posterior triangle of the neck, the adjacent paraspinal muscles, and the underlying chest wall. Tumor extension into these anatomic sites must be carefully evaluated prior to surgery because en bloc resection of a chest wall segment or a concomitant neck dissection may be required.

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FIG 1 • Forequarter amputation entails en bloc removal of the upper extremity together with the scapula and the lateral aspect of the clavicle.

INDICATIONS Large soft tissue tumor around the proximal arm/axilla with neurovascular encasement and compromise and extension across the joint (FIG 2) Large bone tumor (primary bone sarcoma or metastatic lesion) of the proximal humerus and scapula with extensive soft tissue component and invasion into the shoulder joint and surrounding muscles (FIG 3) Extensive locoregional tumor recurrence around the shoulder girdle (FIG 4) Palliation of intractable pain or tumor fungation, associated with a rapidly enlarging lesion that has not responded to chemotherapy and/or radiation therapy Forequarter amputation is usually contraindicated when the tumor extends to the chest wall or to the posterior triangle of the neck and paraspinal muscles. This surgery can be considered in selected cases with no metastases, in which concomitant chest wall resection or neck dissection can achieve negative margins and patients can withstand the physiologic impact of these combined major surgeries.4,5 http://e-surg.com

IMAGING AND OTHER STAGING STUDIES The combined use of computerized tomography (CT) and magnetic resonance imaging (MRI) allows determination of the extent of bone and soft tissue tumor involvement and P.148 thus estimation of the potential size of the soft tissue margins, that is, at the neck, paraspinal muscles, and chest wall.

FIG 2 • A. Illustration showing high-grade sarcoma of the proximal arm extending into the axilla, encasing the neurovascular bundle of the upper extremity and crossing the shoulder joint. B. Intraoperative photograph and (C) coronal MRI of a 63-year-old female who presented with a fungating sarcoma of the axilla with extension to the proximal arm and scapula. The neurovascular bundle was encased and compressed by the tumor, and the patient had overt edema of the upper extremity and compromised radial and median nerve functions. Angiography is extremely helpful in locating the anatomic position of the axillary and/or brachial vessels and in evaluating whether these structures are involved by tumor. Physical anomalies (eg, a duplicate axillary artery) can occasionally be identified as well. Angiography also makes it possible to accurately determine the best level of ligation of the axillary vessels. http://e-surg.com

No imaging studies can precisely distinguish whether the brachial plexus is infiltrated by tumor or whether the vessels and plexus are simply displaced, and they provide only indirect evidence of tumor extension to the nerves. On the other hand, we have found venography of the axillary veins to be a simple and accurate method of determining brachial plexus involvement. A brachial venogram will show complete obstruction of the main axillary veins when tumor is infiltrating the brachial plexus, whereas it will show venous patency and displacement when a tumor is adjacent to, but not infiltrating, the plexus.

SURGICAL MANAGEMENT Position The patient is placed in a full lateral position and is secured to the operating table at the hips with tape. Alternatively, a VAC pack can be used to secure the torso. An axillary roll is placed under the axilla to allow full excursion of the chest, and a sponge-rubber pad is placed under the hip to prevent ischemic damage to the skin in this area. The skin is prepared in the usual manner, and the tumorbearing extremity is draped free (FIG 5). P.149

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FIG 3 • A. Illustration showing high-grade sarcoma of the proximal humerus with tumor extension across the joint and around the scapula. B. Intraoperative photograph of a 15-year-old patient who was diagnosed with Ewing sarcoma of the proximal humerus and treated with preoperative chemotherapy and radiation therapy. The tumor grew considerably despite treatment, causing extensive destruction of bone and extension into the surrounding soft tissues as evidenced by the (C) plain radiograph and (D) CT.

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FIG 4 • Intraoperative photographs showing (A) a locally recurrent osteosarcoma at the proximal arm and axilla in a 34-year-old patient and (B) a 59-year-old female with a locally recurrent malignant melanoma extensively involving the arm, axilla, and shoulder that grew rapidly despite chemo-therapy, immunotherapy, and radiation. P.150

FIG 5 • A. The patient is placed in a full lateral position and is secured to the operating table at the hips with tape. Alternatively, a VAC pack can be used to secure the torso. An axillary roll is placed under the axilla to allow full excursion of the chest, and a sponge-rubber pad is placed under the hip to prevent ischemic damage to the skin in this area. The skin is prepared, and the tumor-bearing extremity is draped free. B,C. Positioning of a 35year-old female patient with a recurrent sarcoma of the axilla. Note the scar from the previous surgery at the deltopectoral groove.

TECHNIQUES http://e-surg.com

▪ Incision The anterior component of the incision starts over the clavicle about 2 cm lateral to the sternoclavicular joint. Caudally, the incision line is in or near the deltopectoral groove; superiorly, it crosses the tip of the acromion. These two lines meet below the axilla to include the skin bearing axillary hair and hematoma that results from the biopsy (TECH FIG 1). The final shape of the flaps and position of the lines of incision vary according to the individual tumor extent. Because of the excellent blood supply to the skin in this region, long anterior or posterior flaps generally survive even though they are closed under considerable tension. Occasionally, large tumors extend to the overlying skin and require en bloc resection with a substantial area of skin. This results in a wound defect that cannot be closed primarily and will require a skin graft or be left for a delayed wound closure. The anterior skin flap, which can be extended to the midsternum, is usually constructed first, with the surgeon standing in front of the patient. The surgeon then switches position to stand behind the patient and constructs the posterior flap to the medial border of the scapula.

TECH FIG 1 • A. The anterior component of the incision starts over the clavicle about 2 cm lateral to the sternoclavicular joint. Caudally, the incision line is in or near the deltopectoral groove; superiorly, the incision line crosses the tip of the acromion. Intraoperative photographs showing the anterior (B) and posterior (C) arms of the incision. These two lines meet below the axilla to include the skin bearing axillary hair. (continued) P.151 http://e-surg.com

TECH FIG 1 • (continued)

▪ Removal of the Affected Limb and Scapula Anterior vascular exploration is performed by detaching the pectoralis major muscle from the clavicle. A clavicular osteotomy is performed at the proximal one-third junction, and the underlying brachial plexus and subclavian vessels are identified (TECH FIG 2). A Satinsky clamp can be placed high along the vessels and surgery can then proceed as planned. The posterior approach is used to detach the scapula from the rhomboid, trapezius, levator scapulae, and latissimus dorsi muscles (TECH FIG 3). The scapula is lifted from the chest wall by detaching the serratus anterior muscle from its inner plate and the latissimus dorsi at its lowest point (TECH FIG 4). This exposes the posterior chest wall and allows the surgeon to place his or her hand into the axillary space to check for chest wall or intercostal muscle involvement (TECH FIG 5), whereupon the planned amputation can proceed. If there is chest wall involvement, a combined chest wall/forequarter amputation can be performed. An axillary incision is made to connect the anterior and posterior incisions. The entire forequarter is removed after ligation and transection of the brachial plexus and subclavian vessels (TECH FIG 6).

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TECH FIG 2 • Most of the forequarter amputation operation is performed anteriorly. A,B. The anterior flap is elevated, exposing the clavicle, acromion, and the overlying origin of the pectoralis major muscle. (continued) P.152

TECH FIG 2 • (continued) C. Intraoperative photograph of the posterior deltoid pectoralis myocutaneous flap (elevated). D. The origin of the muscle is detached from the clavicle and an osteotomy is performed. E. http://e-surg.com

The underlying brachial plexus and subclavian vessels are identified and clamped.

TECH FIG 3 • A-C. Detachment of the scapular attachments of the rhomboids, trapezius, levator scapulae, and latissimus dorsi muscles. (continued) P.153

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TECH FIG 3 • (continued) P.154

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TECH FIG 4 • A,B. Lifting of the scapula from the chest wall by detaching the serratus anterior muscle from its inner plate and the latissimus dorsi at its lowest point. P.155

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TECH FIG 5 • A,B. Exposure of the posterior chest wall. This allows the surgeon to palpate the surface of the chest wall and axilla for tumor detection and determine if amputation can proceed as planned or if additional chest wall resection is required. P.156

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TECH FIG 6 • A. The subclavian vessels are ligated and the brachial plexus transected. B. This allows removal of the forequarter. C. Note the use of epineural catheters in the brachial plexus. These silastic catheters are used to deliver postoperative analgesics, particularly 0.25% Marcaine.

▪ Soft Tissue Reconstruction and Wound Closure The area is copiously irrigated. The large posterior flap is closed over the remaining chest wall defect (TECH FIG 7). Marked redundancy of the skin may present an unacceptable cosmetic appearance, so every effort should be made to ensure that the skin flaps are carefully approximated. The midportion of the long posterior skin flap is approximated to the midportion of the anterior flap. Carrying out the closure in this way pleats the longer posterior skin flap and prevents unsightly folds of skin. A two-layered closure, first of superficial fascia and then of skin, is used. Generous suction drainage under the anterior and posterior skin flaps is secured (TECH FIG 8). http://e-surg.com

Suction drains are removed when serous drainage is minimal. P.157

TECH FIG 7 • A. Illustration showing the exposed chest wall and fasciocutaneous flaps remaining after forequarter amputation. B,C. Intraoperative photographs showing mobilization of the large posterior flap anteriorly over the chest wall. P.158

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TECH FIG 8 • Wound closure over suction drains.

PEARLS AND PITFALLS Indications

▪ Mandatory preoperative detailed radiologic assessment of the soft tissue extents of the tumor, its vascular anatomy, and determination of neck and chest wall invasion. If the latter exists and amputation is feasible, make the necessary preparations for concomitant chest wall resection or neck dissection.

Positioning and resection

▪ Patient is placed in a full lateral position. Clavicular osteotomy and clamping of the subclavian vessels are done first. ▪ Intraoperative palpation of the chest wall to assess tumor extension ▪ Trimming of the posterior flap to avoid redundancy and formation of skin folds

Analgesia

▪ Marcaine infusion through an epineural catheter in the nerve sheath in an effort to decrease postoperative pain and causalgia

Postoperative care

▪ Assisted postoperative ambulation to avoid loss of balance; early occupational therapy

POSTOPERATIVE CARE AND REHABILITATION Continuous suction is usually required for 5 to 7 days, and perioperative intravenous antibiotics are continued until the drainage tubes are removed. Phantom pain (causalgia) is a major problem following high-level amputations. We use an epineural catheter placed into the axillary sheath at the time of surgery and infuse 0.25% Marcaine for 3 to 5 days postoperatively. This decreases postoperative pain and may lessen late causalgia syndromes. Patients initially have difficulties in keeping their balance because of the acute weight inequality of their upper torso and tend to fall toward the contralateral side. This problem typically resolves itself after a few days of assisted walking. It is crucial to have an occupational therapist involved early in the postoperative period to teach the patient how to perform the activities of daily living with a single upper extremity. This is even more critical when the http://e-surg.com

amputated extremity is the dominant one. A cosmetic prosthesis can be fitted upon wound healing and resolution of wound edema, usually 4 to 6 weeks after surgery.

OUTCOMES Forequarter amputation is a mutilating procedure that has a profound aesthetic, psychological, and functional impact on the patients. It is done for large and aggressive tumors, which bear high risk of metastatic dissemination. Most patients who undergo forequarter amputation gain local control over their tumor but still face the likelihood of distant metastases. P.159

FIG 6 • A,B. Photograph of a 65-year-old female patient who underwent forequarter amputation for a large recurrent sarcoma of the axilla, showing the typical deformity of the shoulder girdle. C,D. A custommade prosthesis provides a reasonable cosmetic appearance. E. Forequarter amputation is often a curative procedure. This clinical photograph shows the incision of a patient who underwent forequarter amputation 5 years ago. Pain relief and improved quality of life are pronounced in patients who had undergone palliative amputation to control intractable pain associated with a rapidly enlarging tumor that had not responded to chemotherapy and radiation therapy. Most patients who undergo forequarter amputation regain reasonable function and are able to perform http://e-surg.com

most daily activities (FIG 6). For some yet undefined reason, phantom limb pain is less common and disturbing than that associated with high amputation of the lower extremities.

COMPLICATIONS Flap ischemia, which is usually superficial and marginal because of the good blood supply of the shoulder girdle (FIG 7), typically resolves spontaneously. Occasionally, there is full-thickness necrosis of the posterior flap. A clear demarcation line appears after 4 to 7 days, after which débridement of the necrotic segment and primary closure are carried out. Phantom limb pain Local tumor recurrence P.160

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FIG 7 • Superficial flap ischemia occurring 3 days after surgery in a 37-year-old patient who underwent forequarter amputation for locally progressive malignant melanoma. The ischemic changes resolved spontaneously after 5 days.

REFERENCES 1. Bhagia SM, Elek EM, Grimer RJ, et al. Forequarter amputation for high-grade malignant tumours of the shoulder girdle. J Bone Joint Surg Br 1997;79:924-926. 2. Bickels J, Wittig JC, Kollender Y, et al. Limb-sparing resections of the shoulder girdle. J Am Coll Surg 2002;194:422-435. 3. Ferrario T, Palmer P, Karakousis CP. Technique of forequarter (interscapulothoracic) amputation. Clin Orthop Relat Res 2004;423:191-195. 4. Fianchini A, Bertani A, Greco F, et al. Transthoracic forequarter amputation and left pneumonectomy. Ann Thorac Surg 1996;62: 1841-1843. 5. Kuhn JA, Wagman LD, Lorant JA, et al. Radical forequarter amputation with hemithoracectomy and free extended forearm flap: technical and physiologic considerations. Ann Surg Oncol 1994;1: 353-359. 6. Levine EA, Warso MA, McCoy DM, et al. Forequarter amputation for soft tissue tumors. Am Surg 1994;60:367-370. 7. Merimsky O, Kollender Y, Inbar M, et al. Is forequarter amputation justified for palliation of intractable cancer symptoms? Oncology 2001;60:55-59. 8. Roth JA, Sugarbaker PH, Baker AR. Radical forequarter amputation with chest wall resection. Ann Thorac Surg 1984;37:423-427. 9. Wittig JC, Bickels J, Kollender Y, et al. Palliative forequarter amputation for metastatic carcinoma to the shoulder girdle region: indications, preoperative evaluation, surgical technique, and results. J Surg Oncol 2001;77:105-113.

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Chapter 15 Above-Elbow and Below-Elbow Amputations Jacob Bickels Yair Gortzak Yehuda Kollender Martin M. Malawer

BACKGROUND Tumors of the upper extremity may cause extensive soft tissue and bone destruction and extend into the main neurovascular bundle. In those extreme situations, limb sparing may not be feasible, and amputation is required to achieve wide margins of resection and local tumor control. Above-elbow amputations may be required for advanced soft tissue and bone sarcomas of the forearm and around the elbow (FIG 1A); below-elbow amputations are performed for such tumors of the forearm and the hand (FIG 1B). Above- and below-elbow amputations are rarely done because the upper arm, elbow, and forearms are rare location for musculoskeletal tumors and because tumors at that site are noticed in relatively early stages and in most cases are resectable. Furthermore, administration of preoperative chemotherapy and availability of isolated limb perfusion have allowed to control the majority of patients that present with a large tumor. Nonetheless, above- and below-elbow amputations retain a definitive role in the management of soft tissue and bone tumors of the upper extremity.

ANATOMIC CONSIDERATIONS Above-elbow amputations can be metaphyseal (high), diaphyseal, or supracondylar (see FIG 1A).

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FIG 1 • A. Above-elbow amputations are done for advanced soft tissue and bone sarcomas of the forearm. Skin incisions and osteotomy sites for metaphyseal (high), diaphyseal, and supracondylar aboveelbow amputations. B. Below-elbow amputations are done for advanced soft tissue and bone tumors of the forearm and hand. Skin incision and osteotomy site for below-elbow amputation. High above-elbow amputations are those proximal to the deltoid tuberosity. Patients who undergo amputation proximal to the insertions of the deltoid and pectoralis major muscles have far greater difficulties adjusting to their prosthesis than do those who have undergone a more distal amputation. Below-elbow amputations should preserve the maximal length of both radius and ulna. Although tumors of the hand are treated by a standard below-elbow amputation, performed through the distal third of the forearm, tumors of the distal forearm require a higher amputation and warrant special consideration. A minimum of 2.5 to 3 cm of bony stump, measured from the radial tuberosity, is required to preserve function. Additional length in a very short stump can be obtained by releasing the biceps tendon; adequate flexion of the stump will be provided by the brachialis muscle.

INDICATIONS Extensive soft tissue and bone tumor extension with no option for reconstruction and reasonable function following resection (FIGS 2,3 and 4) Local recurrence was once considered a primary indication for amputation. The mere presence of a recurrent sarcoma is no longer an immediate indication for an amputation. P.162 P.163 P.164 http://e-surg.com

The capability to resect the recurrent tumor without compromising the function of the extremity is the determining factor on which the decision to amputate is based (FIG 5).

FIG 2 • A. Clinical picture and (B) plain radiograph showing metastatic carcinoma of lung to the mid-ulna with extensive bone destruction and soft tissue extension. C,D. Plain radiographs showing high-grade sarcoma of the proximal radius associated with extensive soft tissue extension. These tumors necessitate above-elbow amputation to achieve local tumor control and palliate pain.

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FIG 3 • A. Clinical picture and (B) plain radiograph showing high-grade sarcoma of the first metacarpus. C. Fungating soft tissue sarcoma of the hand. D. Extensive necrotic and fungating sarcoma of the wrist. These tumors necessitate below-elbow amputation to achieve local tumor control.

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FIG 4 • Extensive squamous cell carcinomatosis of the forearm. Above-elbow amputation was done.

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FIG 5 • Recurrent high-grade sarcoma of the distal forearm. The recurrent disease is diffused and wide resection would result in loss of neurovascular structures and all flexor tendons and would end with an extensive soft tissue defect in a previously irradiated surgical field. Belowelbow amputation was, therefore, done (planned incision is outlined). Major vascular involvement. The neurovascular bundle within the arm is tightly integrated in a closed anatomic space. The cephalic vein usually provides sufficient collateral flow if the brachial or the axillary vein has to be sacrificed. However, although occasionally the tumor mass can be delicately dissected off the brachial artery, in most cases of vascular involvement, the brachial artery is extensively encased and amputation is inevitable (FIG 6). The compact nature of the vascular supply to the wrist makes involvement of the radial and ulnar arteries likely when a large tumor invades the volar aspect of the distal forearm. In this instance, the incidence of morbidity and failure associated with resection and reconstruction using a vascular graft of one of these vessels is prohibitively high. Major nerve involvement. In general, one nerve around the arm can be sacrificed and a two-nerve deficit is tolerated. Sacrifice of the three major nerves leaves the patient with a functionless extremity that is better off amputated. Nerve grafting for replacement of a section of the median, radial, or ulnar nerves is still not associated with satisfactory function.

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FIG 6 • MRI demonstrating tendon and neurovascular involvement, a true indication for amputation.

IMAGING AND OTHER STAGING STUDIES Patients requiring above- or below-elbow amputations for a soft tissue or primary bone sarcoma must undergo complete staging in order to allow the surgeon to determine the level of amputation and extent of soft tissue resection. Complete staging allows determination of full tumor extent and, as a result, the site for skin incision, shape of the flaps, and site of osteotomy. The combined use of plain radiography, computerized tomography (CT), and magnetic resonance imaging (MRI) is necessary to determine the proximal extent of the intraosseous and soft tissue components of the tumor. In general, the more proximal of the two levels of involvement (ie, bone or soft tissue) determines the level of amputation.

SURGICAL MANAGEMENT http://e-surg.com

Positioning The patient is supine with the ipsilateral shoulder slightly elevated.

TECHNIQUES ▪ Amputations at the Elbow Standard anterior/posterior “fish-mouth” flaps are used. However, medial-lateral flaps may occasionally be needed because of local tumor anatomy. Because of the excellent blood supply to the upper extremity, wound healing is rarely a problem, regardless of flap configuration. The skin and superficial fascia are divided perpendicular to the skin surface (TECH FIG 1). Large blood vessels are ligated in continuity and then suture ligated. The nerves are handled delicately. They are pulled approximately 2 cm from their muscular bed, doubly ligated with nonabsorbable monofilament suture, and cut with a knife. Muscles are transected according to the flap design and the humerus or the radius and ulna are cut at the appropriate location, as determined by the preoperative imaging studies (TECH FIG 2). The radius and ulna are transected at equal lengths. For optimal function and mobility of the stump, it is important that muscle groups will be positioned tightly and securely over the cut ends of the bones (TECH FIG 3). Myodesis is reinforced by Dacron tapes passed through drill holes made in the cut end of the bone. Superficial fascia and skin are closed over closed suction drains (TECH FIG 4). P.165

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TECH FIG 1 • A. Anterior/posterior fish-mouth flaps are used. B. The skin and superficial fascia are divided perpendicular to the skin surface. C-E. Intraoperative photographs representing the flap development and exposure of the soft tissues and neurovasculature prior to osteotomy. P.166

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TECH FIG 2 • Osteotomies are performed at the appropriate location, as determined by the preoperative imaging studies: (A) above-elbow amputation and (B) below-elbow amputation. For above-elbow amputation, the osteotomy is done at the distal third of the humerus; for below-elbow amputation, the radius and ulna are transected at equal lengths at the appropriate level.

TECH FIG 3 • Muscle groups are positioned tightly and securely over the transected bone ends: (A) aboveelbow amputation and (B) below-elbow amputation.

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TECH FIG 4 • Superficial fascia and skin are closed over closed suction drains: (A) above-elbow amputation and (B) below-elbow amputation. Final closure for above-elbow amputation (C) and belowelbow amputation (D) with closed suction drains. (continued) P.167

TECH FIG 4 • (continued) E. Closed surgical wound over an epineural catheter which provides continuous flow of local analgesics was installed into the nerve sheath to control postoperative pain. http://e-surg.com

PEARLS AND PITFALLS Radiology

▪ Detailed preoperative imaging for evaluation of tumor extent

Operative procedure

▪ Functional and tight myodesis over the cut ends of the bones

Postoperative care and rehabilitation

▪ Rigid dressing and early range-of-motion exercises

POSTOPERATIVE CARE A rigid dressing is applied immediately postoperatively to decrease pain and edema and facilitate maturation of the stump (FIG 7). Care must be taken to adequately protect the skin that directly overlies the bone. Stump edema is rarely a significant problem in the upper extremity, and prosthesis training should begin as soon as possible after surgery. Continuous suction is required for 3 to 5 days, and perioperative intravenous antibiotics are continued until the drainage tubes are removed. Active and passive ranges of motion around the shoulder and elbow (if exists) are practiced as tolerated.

COMPLICATIONS Wound dehiscence Deep infection Loss of elbow motion (when above-elbow amputation is done) Phantom limb pain

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FIG 7 • A rigid dressing is used to decrease postoperative pain and edema: (A) above-elbow amputation and (B) below-elbow amputation.

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Chapter 16 Primary and Metastatic Tumors of the Spine: Total En Bloc Spondylectomy Hideki Murakami Norio Kawahara Katsuro Tomita

BACKGROUND Conventionally, curettage or piecemeal excision has been the usual approach to vertebral tumors. These approaches have clear disadvantages, however, including high risk of tumor cell contamination to the surrounding structures and residual tumor tissue at the site due to difficulty in demarcating tumor from healthy tissue. These contribute to incomplete resection of the tumor as well as high local recurrence rates of the spinal malignant tumor. To reduce local recurrence and to increase survival, we have developed total en bloc spondylectomy (TES).10,11,14 In this method, the entire vertebra or vertebrae containing the malignant tumor are resected, together with en bloc laminectomy, en bloc corpectomy, and bilateral pediculotomy using a T-saw through the posterior approach.9 Using this technique, we are able to excise the tumor mass together with a wide or marginal margin.

ANATOMY The following tissues serve as barriers to spinal tumor progression: the anterior longitudinal ligament (ALL), the posterior longitudinal ligament (PLL), the periosteum abutting the spinal canal, the ligamentum flavum (LF), the periosteum of the lamina and spinous process, the interspinous ligament (ISL), the supraspinous ligament (SSL), the cartilaginous endplate, and the cartilaginous annulus fibrosus. However, both the PLL and the periosteum on the lateral side of the vertebral body are “weak” anatomic barriers. In contrast, the ALL, cartilaginous endplate, and annulus fibrosus are “strong” barriers. In the spine, one vertebra could be regarded as a single oncologic compartment and the surrounding tissues as barriers to tumor spread (FIG 1).5

FIG 1 • Compartment and barrier. SSL, supraspinous ligament; LF, ligamentum flavum; PLL, posterior longitudinal ligament; ALL, anterior longitudinal ligament; CL, capsular ligament; ISL, interspinous ligament.

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INDICATIONS Surgical indication for primary tumors The surgical strategy for primary spinal tumors used at the authors' institution is based on Enneking's concept of musculoskeletal tumors3 (Table 1). Surgical indication for metastatic tumors Surgical strategy for spinal metastases (Table 2) consists of three prognostic factors12: Grade of malignancy Visceral metastases Bone metastases The extent of the spinal metastases is stratified using the surgical classification of spinal tumors (Table 3), and technically appropriate and feasible surgery is employed, such as en bloc spondylectomy, piecemeal thorough excision, curettage, or palliative surgery. P.169

Table 1 Surgical Strategy for Primary Spinal Tumors

Surgical Staging

Contamination/Residual Tumor

Surgical Margin

Spinal Cord Salvage Surgery

Benign tumor 1. Latent

Don't touch!

2. Active

OK/OK

Intralesional

Debulking (piecemeal)

3. Aggressive

No/no

Intralesional or marginal

Thorough excision (piecemeal/en bloc)

Total en bloc excision

Malignant tumor I. Low grade

No/no

II. High grade

No/no

Marginal or wide

III. With metastases

No/no

(Radical: impractical)

Table 2 Surgical Strategy for Spinal Metastases

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Table 2 Appendix Points for Each Primary Tumor 1 point = slow growth

4 points = rapid growth

Breast cancer*

Lung cancer

Thyroid cancer*

Gastric cancer, esophageal cancer

Prostatic cancer, testicular cancer

Nasopharyngeal cancer

2 points = moderate growth

Hepatocellular cancer

Renal cell cancer*

Pancreas cancer, etc.

Uterus cancer, ovarian cancer

Bladder cancer

Colorectal cancer

Melanoma Sarcoma (osteosarcoma, Ewing sarcoma, leiomyosarcoma, etc.) Primary unknown metastasis Other rare cancers … etc.

*Rare types of

the following cancers should be given 4 points as rapidly growing cancers: breast cancer, inflammatory type; thyroid cancer, undifferentiated type; renal cell cancer, inflammatory type.

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Table 3 Surgical Classification of Spinal Tumors Intracompartmental Type 1 Vertebral body

Extracompartmental Type 4 Spinal canal extension

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Multiple Type 7

Type 2 Pedicle extension

Type 5 Paravertebral extension

Type 3 Body lamina extension

Type 6 Adjacent vertebral extension

IMAGING AND OTHER STAGING STUDIES Plain radiography Computed tomography/magnetic resonance imaging Bone scan Angiography and other studies Biopsy

SURGICAL MANAGEMENT The TES operation was designed to achieve complete tumor resection en bloc, including main and satellite microlesions in a vertebral compartment to avoid local recurrence. The primary candidates for TES are primary malignant tumor (stage 1, 2), aggressive benign tumor (stage 3), and isolated metastasis in a patient with long life expectancy (see Tables 1 and 2). From the viewpoint of tumor growth (see Table 3), TES is recommended for types 3, 4, and 5 lesions and relatively indicated for types 1, 2, and 6 lesions. Type 1 or 2 still can be a candidate for radiation therapy, chemotherapy, corpectomy, or hemivertebrectomy.

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TES is not recommended for type 7 lesions. Systemic treatment or hospice care may be the treatment choice for these lesions.10,11,13 However, the final decision can be made individually based on discussion among the patient and his or her family and doctors.

Preoperative Embolization Segmental arteries above and below the feeding artery, as well as the feeding artery itself, should be embolized preoperatively. This embolization technique dramatically reduces intraoperative bleeding without compromising spinal cord function.4,8,15

Positioning The patient is placed prone over the Relton-Hall four-poster frame for the posterior approach to avoid compression to the vena cava.

Approach The surgical approach is decided based on the degree of tumor development or affected spinal level. Single posterior approach For TES above L4, a single posterior approach is preferred rather than a posteroanterior combined approach as long as the tumor does not involve major vessels or segmental arteries. Anteroposterior double approach In type 5 or 6 tumors that involve major vessels or segmental arteries, anterior dissection followed by posterior TES is indicated. Currently, a thoracoscopic or mini-open approach is preferred for anterior dissection. Posteroanterior double approach Posterior laminectomy and stabilization followed by anterior en bloc corpectomy and placement of a vertebral prosthesis is indicated in spinal tumors at the level of L5 or L4 because of the technical challenge presented by the iliac wing and lumbosacral plexus nerves. P.171

TECHNIQUES ▪ Exposure A straight vertical midline incision is made over the spinous processes and is extended three vertebrae above and below the involved segment(s). The paraspinal muscles are dissected from the spinous processes and the laminae and then retracted laterally. If the patient underwent a posterior route biopsy, the tracts are carefully resected in a manner similar to that used in limbsalvaging procedures. After a careful dissection of the area around the facet joints, a large retractor, the articulated spinal retractor, which has a uniaxial joint in each limb and was designed for this surgery, is applied.

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TECH FIG 1 • A. Exposure. B. Ribs on the affected level are transected 3 to 4 cm lateral to the costotransverse joint. By spreading the retractor and detaching the muscles around the facet joints, a wider exposure is then obtained. The operative field must be wide enough on both sides to allow dissection under the surface of the transverse processes. In the thoracic spine, the ribs on the affected level are transected 3 to 4 cm lateral to the costotransverse joint, and the pleura is bluntly separated from the vertebra (TECH FIG 1). To expose the superior articular process of the uppermost vertebra, the spinous and inferior articular processes of the neighboring vertebra are osteotomized and removed with dissection of the attached soft tissues, including the ligamentum flavum.

▪ Introduction of the T-Saw Guide To make an exit for the T-saw guide through the nerve root canal, the soft tissue attached to the inferior aspect of the pars interarticularis is dissected and removed using utmost care so as not to damage the corresponding nerve root. A C-curved malleable T-saw guide is then introduced through the intervertebral foramen in a cephalocaudal direction. In this procedure, the tip of the T-saw guide should be introduced along the medial cortex of the lamina and the pedicle so as not to injure the spinal cord and the nerve root (TECH FIG 2).

TECH FIG 2 • A. Schematic diagram depicting introduction of the T-saw guide. B. A C-curved malleable guidewire is introduced through the right intervertebral foramen in a cephalocaudal direction. After passing the T-saw guide, its tip at the exit of the nerve root canal can be found beneath the inferior border of the pars interarticularis. A T-saw is passed through the hole in the wire guide and is clamped with a T-saw holder at each end. The T-saw guide is removed, and tension on the T-saw is maintained. P.172

▪ Cutting the Pedicles and En Bloc Laminectomy While tension is maintained, the T-saw is placed beneath the superior articular and transverse processes with a specially designed T-saw manipulator. With this procedure, the T-saw placed around the lamina is wrapped around the pedicle.

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With a reciprocating motion of the T-saw, the pedicles are cut, and then the whole posterior element of the spine (the spinous process, the superior and inferior articular processes, the transverse process, and the pedicle) is removed in one piece (TECH FIG 3). The cut surface of the pedicle is sealed with bone wax to reduce bleeding and to minimize contamination by tumor cells.1

TECH FIG 3 • A,B. Right pedicle is cut with a reciprocating motion of the T-saw. C. Schematic drawing of the pediculotomy. To maintain stability after segmental resection of the anterior column, a temporary posterior instrumentation (“two above and two below” segmental fixation) is performed. Blunt Dissection around the Vertebral Body The spinal branch of the segmental artery, which runs along the nerve root, is ligated and divided. In the thoracic spine, the nerve root is cut on the side from which the affected vertebra is removed. The blunt dissection is done on both sides through the plane between the pleura (or the iliopsoas muscle) and the vertebral body (TECH FIG 4). Usually, the lateral aspect of the body is easily dissected with a curved vertebral spatula. Then the segmental artery should be dissected from the vertebral body. P.173 By continuing dissection of both lateral sides of the vertebral body anteriorly, the aorta is carefully dissected posteriorly from the anterior aspect of the vertebral body with a spatula and the surgeon's fingers. When the surgeon's fingertips meet with each other anterior to the vertebral body, a series of spatulas, starting from the smallest size, are inserted sequentially to extend the dissection. A pair of the largest spatulas is kept in the dissection site to prevent the surrounding tissues and organs from iatrogenic injury and to make the surgical field wide enough for the surgeon to manipulate the anterior column.

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TECH FIG 4 • A. Schematic drawing of anterior dissection around the vertebral body. Segmental arteries on the right (B) and left (C) sides. D,E. Schematic drawings of anterior finger dissection around the vertebral body show the posterior (D) and axial (E) views. (continued) P.174

TECH FIG 4 • (continued) F. Anterior finger dissection around the vertebral body. G. A pair of spatulas is kept around the affected vertebral body to protect the surrounding tissues and organs from iatrogenic injury and to make the surgical field wide enough for manipulation of the anterior column.

▪ Dissection of the Spinal Cord and En Bloc Corpectomy Using a cord spatula, the spinal cord (dura mater) is mobilized from the surrounding venous plexus and the ligamentous

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tissue. T-saws are inserted at the proximal and distal cutting levels of the vertebral bodies after confirmation of the disc levels with needles. Recently, a diamond T-saw is now available for corpectomy. The teeth-cord protector, which has teeth on both edges to prevent the T-saw from slipping, is then applied. The anterior column of the vertebra is cut by the T-saw, together with the anterior and posterior longitudinal ligaments (TECH FIG 5). The freed anterior column is rotated around the spinal cord and removed carefully to avoid injury to the spinal cord. With this procedure, a complete anterior and posterior decompression of the spinal cord (circumspinal decompression) and total en bloc resection of the vertebral tumor are achieved.

TECH FIG 5 • A. A temporary posterior instrumentation is performed to maintain stability after segmental resection of the anterior column. B,C. The anterior column of the vertebra is cut by the T-saw, together with the anterior and posterior longitudinal ligaments. The teeth-cord protector, which has teeth on both edges to prevent the T-saw from slipping, is then applied. (continued) P.175

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TECH FIG 5 • (continued) D. Schematic drawing of cutting the anterior column. E. Diagram of en bloc corpectomy. F. Intraoperative photograph of specimen from the resected T7 vertebra. G. Specimens resected along with the compartment and barrier concept. H,I. Radiographs of resected specimens from metastatic tumor of T7 showing the complete vertebra in horizontal (H) and lateral (I) views. P.176

▪ Anterior Reconstruction and Posterior Instrumentation An anchor hole on the cut end of the remaining vertebra is made on each side to seat the graft. A vertebral spacer such as a titanium mesh cylinder cage with autograft, allograft, or cement (TECH FIG 6) is properly inserted to the anchor holes within the remaining healthy vertebrae. After checking the appropriate position of the vertebral spacer radiographically, the posterior instrumentation is adjusted to slightly compress the inserted vertebral spacer. By this “spinal shortening” procedure, the block cylinder is caught tightly, and the anteroposterior 360-degree spinal reconstruction is completed. 2,7 If two or three vertebrae are resected, it is recommended that the connector device be applied between the posterior rods and anterior spacer (artificial pedicle).

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TECH FIG 6 • A. A vertebral spacer is properly inserted to the anchor holes within the remaining healthy vertebrae. B. Schema of reconstruction (lateral view). C,D. After checking the appropriate position of the vertebral spacer radiographically, the posterior instrumentation is adjusted to slightly compress (10 mm in this case) the inserted vertebral spacer. E,F. Postoperative radiograph after spinal column shortening shows three pairs of preoperative embolization coils. (continued) P.177

TECH FIG 6 • (continued) G-I. Resection of two vertebrae. G. Bilateral artificial pedicles are placed. H,I. Postoperative radiographs of reconstruction with artificial pedicle.

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PEARLS AND PITFALLS Bleeding from the epidural venous plexus12

▪ Fibrin glue 1.5 mL that is injected manually into the epidural space in both the cranial and caudal direction of the targeted vertebra after en bloc laminectomy helps reduce oozing from the epidural venous plexus.

Blunt dissection around the vertebral body

▪ Careful step-by-step dissection with anatomic consideration is an important fundamental. ▪ Preceding TES by a posterior approach, vessels around the vertebral body are managed anteriorly using thoracoscopy or a minimally open approach. This is safer than performing TES by a single posterior approach in a patient in whom the segmental artery(ies) may be involved by the tumor. ▪ At lesions of L1 and L2, the diaphragm insertions should be dissected from the vertebral body before the lumbar arteries are dissected because the segmental arteries run between the vertebral body and diaphragm insertion. 6

Ligation of the segmental arteries

▪ Ligation of the segmental arteries up to three vertebral levels, even including a branch of the artery of Adamkiewicz, may not affect the spinal cord evoked potentials and spinal cord function.4,8,15

Spinal cord injury

▪ Mechanical damage to the neural structures, especially shifting aside, twisting, and hanging down or upward of the cord, should be avoided. ▪ Spinal cord stretching causes irreversible mechanical damage. Excessive nerve root traction also damages the cord due to the root avulsion mechanism.

Risk of tumor cell contamination13

▪ Double rinsing with distilled water and highly concentrated cisplatinum is recommended to eradicate contaminated cancer cells.

Spinal shortening

▪ The posterior instrumentation is adjusted to compress the inserted vertebral prosthesis slightly (5-10 mm) to secure it as a final step of spinal reconstruction using TES. ▪ This process of spinal shortening provides two important advantages: (1) increased spinal stability of the anterior and posterior spinal column and (2) increased spinal cord blood flow, which is desirable to improve spinal cord function. 7

P.178

POSTOPERATIVE CARE Suction drainage is used for 3 to 5 days after surgery. The patient is allowed to start walking within 1 week after surgery. The patient wears a thoracolumbosacral orthosis for 3 to 6 months until bony union is attained.

OUTCOMES From 1989 to 2003, 284 patients with spinal tumors (primary, 86 patients; metastasis, 198 patients) were surgically treated and followed for a minimum of 2 years. TES was performed in 33 of the 86 patients with a primary tumor; 17 patients with malignant tumors (3 osteosarcoma, 3 Ewing sarcoma, 3 plasmocytoma, 2 chondrosarcoma, and 1 case each of 6 other tumors) and 16 patients with aggressive benign tumors (4 patients with giant cell tumor, 3 patients with osteoblastoma, 3 patients with symptomatic hemangioma, and 1 case each of 6 other tumors). Five-year survival of the 17 patients with primary malignant spinal tumors (stages 1 and 2) who underwent TES was 67% and that of the 16 patients with aggressive benign tumors (stages 2 and 3) was 100%. In the same periods, TES was performed in 64 of 198 patients with spinal metastases. Of the 64 cases with a metastatic tumor, the primary organs were as follows: kidney, 18 cases; breast, 15 cases; thyroid, 9 cases; lung, 4 cases; liver, 4 cases; and other carcinoma, 14 cases. Forty-three patients with the 2, 3, and 4 points out of 64 patients who underwent TES resulted in 2-year survival of 66.6% and 5-year survival of 46.6%. Ninety-two of 97 patients (95%) had no tumor recurrence until death or last follow-up. Five of 97 patients (5%) had local recurrence; the mean length of the recurrence was 22.1 months after operation. In all five patients with local recurrence, the recurrence arose from residual tumor tissue.

COMPLICATIONS http://e-surg.com

Excessive bleeding Injury of the major vessels during blunt dissection of the vertebral body Spinal cord injury Injury of lung or pleura Postoperative hematoma Liquorrhea Pleural effusion Chylothorax Instrumentation failure Infection, especially after preoperative radiation therapy

REFERENCES 1. Abdel-Wanis ME, Tsuchiya H, Kawahara N, et al. Tumor growth potential after tumoral and instrumental contamination: an in-vivo comparative study of T-saw, Gigli saw, and scalpel. J Orthop Sci 2001;6:424-429. 2. Akamaru T, Kawahara N, Sakamoto J, et al. The transmission of stress to grafted bone inside a titanium mesh cage used in anterior column reconstruction after total spondylectomy: a finite-element analysis. Spine 2005;30:2783-2787. 3. Enneking WF, Spanier SS, Goodmann MA. A system for the surgical staging of musculoskeletal sarcoma. Clin Orthop 1980;153:106-120. 4. Fujimaki Y, Kawahara N, Tomita K, et al. How many ligations of bilateral segmental arteries cause ischemic spinal cord dysfunction? An experimental study using a dog model. Spine 2006;31: E781-E789. 5. Fujita T, Ueda Y, Kawahara N, et al. Local spread of metastatic vertebral tumors. A histologic study. Spine 1997;22:19051912. 6. Kawahara N, Tomita K, Baba H, et al. Cadaveric vascular anatomy for total en bloc spondylectomy in malignant vertebral tumors. Spine 1996;21:1401-1407. 7. Kawahara N, Tomita K, Kobayashi T, et al. Influence of acute shortening on the spinal cord: an experimental study. Spine 2005;30:613-620. 8. Numbu K, Kawahara N, Murakami H, et al. Interruption of bilateral segmental arteries at several levels. Influence on vertebral blood flow. Spine 2004;29:1530-1534. 9. Tomita K, Kawahara N. The threadwire saw: a new device for cutting bone. J Bone Joint Surg Am 1996;78A:1915-1917. 10. Tomita K, Kawahara N, Baba H, et al. Total en bloc spondylectomy. A new surgical technique for primary malignant vertebral tumors. Spine 1997;22:324-333. 11. Tomita K, Kawahara N, Baba H, et al. Total en bloc spondylectomy for solitary spinal metastasis. Int Orthop 1994;18:291-298. 12. Tomita K, Kawahara K, Kobayashi T, et al. Surgical strategy for spinal metastases. Spine 2001;26:298-306. 13. Tomita K, Kawahara N, Murakami H, et al. Total en bloc spondylectomy for spinal tumors: improvement of the technique and its associated basic background. J Orthop Sci 2006;11:3-12.

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14. Tomita K, Toribatake Y, Kawahara N, et al. Total en bloc spondylectomy and circumspinal decompression for solitary spinal metastasis. Paraplegia 1994;32:36-46. 15. Ueda Y, Kawahara N, Tomita K, et al. Influence on spinal cord blood flow and spinal cord function by interruption of bilateral segmental arteries at up to three levels: experimental study in dogs. Spine 2005;30:2239-2243.

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Chapter 17 Surgical Management of Sacral Tumors Xiaohui Niu Hairong Xu

BACKGROUND Tumors involving the sacrum mainly include primary and metastatic tumors. Metastatic tumors are more common than primary ones. The most common benign sacral tumor is giant cell tumor. The most common primary malignant sacral tumor is chordoma followed by chondrosarcoma. Schwannoma, arising from the neural elements and not the sacrum, is categorized into the sacral tumors because it is clinically similar to other sacral tumors and treated the same way as well. The symptoms, which are usually either nonspecific or similar to that of lumbar disc herniation, develop insidiously for months to years due to the potentially large presacral space. The tumors may become very huge before diagnosis. A primary tumor often involving the sacrum is chordoma.1 Tumors in this anatomic location are of low grade and unlikely result in metastatic disease. Problem of local control may be made worse by tumor spill resulting from incomplete excision. Local spill of tumor cells with biopsy, or partial resection by an inexperienced surgeon, may severely compromise the opportunity for a complete recovery. Surgical management of sacral tumors is challenging due to the rich blood supplies and complex anatomic structures (ie, nerves, vessels). It is frequently associated with high risk of local recurrence and complications. Resections of the sacrum are not commonly performed. Operation can be performed safely and deliberately through knowledge of the anatomy in this area and a full knowledge of the principles of dissection. Nerve roots and inferior border of the sacroiliac joints are both the risky locations for positive margins. In rare conditions, tumors may require en bloc resection of the rectum or annal canal plus rectum. The perioperative complications may include massive intraoperative and postoperative bleeding; injury of rectum, bladder, etc.; wound complications; and neurologic dysfunction postoperatively. In the recent years, the computer-assisted navigation technology has shown promise in aiding in optimal preoperative planning and in providing more precise and accurate tumor resection. Potentially, local recurrence may be reduced and neurologic function may be preserved at its best by applying this technology. Radiation for residual may be helpful.

ANATOMY Sacral Plexus and the Coccygeal Plexus Lumbosacral trunk (L4, L5) courses over the sacral ala. The caudal parts of the ventral branches of L4 and L5 combine to form the lumbosacral trunk (FIG 1). Together with the ventral branches of the first three sacral nerves and the upper part of the ventral branch of the fourth sacral nerve, the lumbosacral trunk forms the sacral plexus. http://e-surg.com

S1-S3 roots issue through the upper three anterior sacral foramina, the lumbosacral trunk is joined by S1 at the level of the sacroiliac joint, and S1-S5 exits the foramina sacralia pelvina. The tip of the sacral plexus comes toward the greater sciatic foramen, lying in front of the sacrum and piriformis. The coccygeal plexus arises from the lower part of the ventral branches of the fourth and fifth sacral nerves as well as the coccygeal nerves. The sacral plexus provides motor and sensory nerves for the pelvic, buttocks, perineal region, the posterior thigh, most of the lower leg, the entire foot, and part of the hip joint. Except many short muscle branches for piriformis, musculus obturator internus, and quadratus femoris, the sacral plexus and the coccygeal plexus divide into the following branches. The superior gluteal nerve (L4-L5, S1). The superior gluteal nerve, along with the superior gluteal artery and vein, departs from the pelvis via the suprapiriformis foramen. The nerve supplies the tensor fasciae latae, the gluteus minimus, and the gluteus medius muscles. The inferior gluteal nerve (L5, S1-S2). The inferior gluteal nerve, along with the inferior gluteal artery and vein, departs from the pelvis via the infrapiriformis foramen. The nerve supplies the gluteus maximus. The pudendal plexus. The pudendal plexus is formed by S3-S4 and portions of anterior division of S1-S2. Deep of the origin of the gluteus maximus muscle from the sacral edge, the pudendal nerve must be spared because it courses posterior to the ischial spine and then on the surface of the obturator internus in the ischiorectal fossa. It is in anterior inferior of the sacral plexus but not sharply marked off from it. It gives off the following branches. The muscular branches are derived from the fourth sacral and supply the levator ani, coccygeus, and sphincter ani externus. The visceral branches arise from the third and fourth, and sometimes from the second, sacral nerves and are distributed to the bladder and rectum and, in the female, to the vagina; they communicate with the pelvic plexuses of the sympathetic nervous system. The perineal nerve, the inferior and larger of the two terminal branches of the pudendal nerve, is situated below the internal pudendal artery. Some of the nerve fibers are distributed to the skin of the scrotum and communicate with the perineal branch of the posterior femoral cutaneous nerve. These nerves supply the labium majus in the female. The perineal nerve gives off from the nerve to the bulbocavernosus, pierces this muscle, and supplies the corpus cavernosum urethrae, ending in the P.180 mucous membrane of the urethra. The dorsal nerve of the penis is the deepest division of the pudendal nerve. It gives a branch to the corpus cavernosum penis and passes forward, in company with the dorsal artery of the penis, between the layers of the suspensory ligament, on to the dorsum of the penis, and ends on the glans penis. In the female, this nerve is very small and supplies the clitoris. The fifth sacral nerve receives a communicating filament from the fourth and unites with the coccygeal nerve to form the coccygeal plexus. From this plexus, the anococcygeal nerves take origin; they consist of a few fine filaments that pierce the sacrotuberous ligament to supply the skin in the region of the coccyx.

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FIG 1 • The sacral plexus (A) and the coccygeal plexus (B) distribution. The posterior femoral cutaneous nerve (S1-S3). It leaves the pelvis through the suprapiriformis foramen. It accompanies the inferior gluteal artery to the gluteus maximus and supplies the skin of the back thigh and the popliteal fossa. The sciatic nerve (L4-L5, S1-S3). It is the longest and widest single nerve in the human body. The relationship between the piriformis muscle and the sciatic nerve is close and may be changing. In most instances, the sciatic nerve exits the pelvis via the suprapiriformis foramen. It then lies posterior (superficial) to the short external rotators (superior gemellus, inferior gemellus, and obturator internus). It then runs down the buttocks and the back of the thigh, giving rise to motor branches for the hamstring muscles. When the sciatic nerve reaches the apex of the popliteal fossa, it terminates by bifurcating into the tibial and common fibular nerves. The dural sac ends at the S2-S3 junction. When dural sac is injured, cerebrospinal fluid leak will occur. Radical resection of the entire sacrum would result, in addition to sphincteric incontinence, in considerable denervation of both lower extremities in the distribution of the sciatic nerves. Resections below the body of S3 vertebra do not endanger continence of the anal and bladder functions.

Vascular Anatomy The blood supplies of sacral tumors mainly include internal iliac artery, internal pudendal artery, the superior http://e-surg.com

gluteal artery, the inferior gluteal artery, the vesical artery, the rectal artery, the iliolumbar artery, and the lateral sacral artery (FIG 2). The pertinent blood supplies of sacral tumors, which might be dealt with during operation, mainly include the superior gluteal artery, the lateral sacral artery, and the median sacral artery. There are communications among the superior gluteal artery, the subcostal artery, and the intercostal artery from the abdominal aorta. The superior and inferior arteries also have anastomosis with the femoral profound artery from the lateral iliac artery. There are anastomosis between lateral sacral artery and median sacral artery as well. Venous anatomy generally parallels arterial anatomy but is subject to a high degree of variability and could develop proliferation and enlargement due to the tumors.

Anatomy and Biomechanics of the Sacroiliac Joint The sacroiliac joint is a synovial structure formed between the articular surfaces of the sacrum and ilium. The articular P.181 surface of the sacrum that conjoins with ilium is ear-shaped with complementary irregularities between the articular surfaces, which offer mechanical stability to the joint. The interosseous, anterior, and posterior sacroiliac ligaments are the strongest in this region and function to strengthen the joint.

FIG 2 • The main blood supplies in the sacral area. http://e-surg.com

When the transverse partial sacrectomy is performed just cephalad to the S1 neural foramina and the average resection of the sacroiliac joint is 25%, the bearing capacity of the joint reduces to 35% of the normal. When the transverse partial sacrectomy is performed just caudal to the S1 neural foramina and the average resection of the joint is 16%, the bearing capacity of the joint reduces to 72% of the normal.3 Reconstruction is not needed when performing the transverse partial sacrectomy caudal to the S1 neural foramina. Reconstruction should be considered when performing the transverse partial sacrectomy above the S1 nerve root.

Muscles and Ligaments The gluteus maximus originates from the posterior aspect of dorsal ilium, posterior superior iliac crest, posterior inferior aspect of sacrum and coccyx, and the sacrotuberous ligament. As it passes from the sacrum to the femur, the gluteus maximus covers the sacroiliac joint and the sacrospinous and sacrotuberous ligaments as well as a portion of the ischiorectal fossa. It inserts primarily in fascia lata at the iliotibial band and also into the gluteal tuberosity on posterior femoral surface. The arterial supplies are inferior and superior gluteal arteries and the first perforating branch of the profunda femoris artery. The piriformis is also a very important structure for sacral tumor resection. It originates from the anterior part of the sacrum, the part of the spine in the gluteal region, and from the superior margin of the greater sciatic notch. It exits the pelvis through the greater sciatic foramen to insert on the greater trochanter of the femur. The erector spinae muscle arises from the anterior surface of a broad and thick tendon, which is attached to the medial crest of the sacrum, to the spinous processes of the lumbar, and the supraspinous ligament, to the back part of the inner lip of the iliac crests and to the lateral crests of the sacrum, where it blends with the sacrotuberous and posterior sacroiliac ligaments. Some of its fibers are continuous with the fibers of origin of the gluteus maximus. The sacrotuberous ligament is situated at the lower and back part of the pelvis (FIG 3). It runs from the sacrum (the lower transverse sacral tubercles, the inferior margins sacrum, and the upper coccyx) to the tuberosity of the ischium. The sacrospinous ligament is a narrow ligament attached to the ischial spine and the lateral region sacrum and coccyx. Together with the sacrotuberous ligament, it converts the greater sciatic notch into the greater sciatic foramen and the lesser sciatic notch into the lesser sciatic foramen.

INDICATIONS Surgical indications for primary benign/intermediate tumors such as giant cell tumor of bone, schwannoma, etc. Tumor resection, curettage, or a mixture is recommended. Intralesional margin is acceptable. Surgical indications for primary malignant tumors such as chordoma, chondrosarcoma and Ewing sarcoma, etc. Tumor resection is required with wide or marginal margin. Surgical indications for metastatic tumors. Surgical treatments should be evaluated on a case-by-case basis. Resection, curettage, and ablation are options. Surgical indications for adjacent soft tissue sarcomas involving the sacrum. It is recommended that the tumor and the involved sacrum should be resected en bloc.

PATIENT HISTORY AND PHYSICAL FINDINGS Chronic, dull, lower back or coccygeal pain due to chronic nerve compression is one of the most common presenting symptoms. It could be misdiagnosed as lumbar disc herniation. Some patients are diagnosed http://e-surg.com

incidentally with benign tumors, although asymptomatic. The typical symptom of sacrum tumors is chronic lower back pain with an alteration of bowel or urinary habits due to its mass effect and compression. Ambulation dysfunction and bowel and bladder incontinence may rarely happen. Lower sacral tumors can grow large enough for their anterior portion to be palpated during a rectal examination. Some large sacral tumors such as chordoma and chondrosarcoma present large bumps in the buttock. Those patients with high-grade malignant tumors may suffer severe pain for weeks or months with difficulty in ambulation. Patients usually have to stay in one fixed position to alleviate the pain. The mass is frequently small even if it is palpable during a rectal examination.

IMAGING AND OTHER STAGING STUDIES Plain Radiography Images are often obscure and confusing especially during the early days of the disease. It is hard to arrive at a definite diagnosis with only the plain radiography in most instances. Chordoma usually locates in the lower part of the sacrum and may be diagnosed with plain radiography in the early P.182 days. Lesions of giant cell tumor, simple bone cyst, and aneurysmal bone cyst, usually large and totally lytic, locate in the upper part of the sacrum and may also be diagnosed with plain radiography.

FIG 3 • Anterior (A) and posterior (B) views of the ligaments of the sacrum. Schwannoma in the sacrum almost exclusively originates from the anterior division of the sacral nerve. The enlarged anterior sacral foramina could be easily identified through plain radiography. http://e-surg.com

One should be aware that the diagnosis could be missed or delayed if only the plain radiography is taken. However, plain radiography is necessary with the value of overview on the tumor, correlations with other images, and postoperative follow-up (FIG 4).

Computed Tomography and Magnetic Resonance Imaging Computed tomography (CT) with intravenous contrast is the optimal technique for assessing the extent of bone involvement and destruction, possible ossification or calcification of the P.183 matrix, the anatomic location, the blood supply, and the relation between the tumor and the visceral organs (FIG 5). It is helpful in differential diagnosis of benign and malignant tumors.

FIG 4 • A,B. Chordoma of the sacrum. (continued)

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FIG 4 • (continued) C,D. Giant cell tumor of the sacrum. E,F. Schwannoma of the sacrum. Chest CT is essential for staging purposes in evaluation for pulmonary metastases of malignant tumors. Magnetic resonance imaging (MRI) with contrast is critical for imaging soft tissue mass involvement and the relation between the tumor and the surrounding tissues (ie, vessels, nerves, muscles, visceral organs). MRI is the optimal modality for imaging soft tissue due to its superior discrimination ability than CT. MRI with contrast may be helpful for the serial assessments of neoadjuvant therapy.

Bone Scan Bone scan may sometimes detect small sacral lesions, which are not clearly identified by other radiographs. Bone scan is usually used to rule out systemic disease (ie, metastasis)

Angiography Angiography is necessary for malignant sacral tumors. http://e-surg.com

It is essential to clearly determine the blood supplies of the tumor and the pertinent vascular anatomy with angiography for evaluation of the risk of surgical management. Selective embolization of the tumor blood supplies before surgery is significant in minimizing blood loss during surgery (FIG 6). It has taken the place of ligation and temporary block of arteries in our institution. However, it should be recognized that excessive and large areas of embolization may increase the risks of flap complications.

Positron Emission Tomography-Computed Tomography Positron emission tomography-computed tomography (PET-CT) may be used in assessing malignant sacral tumors, especially metastatic disease. P.184

FIG 5 • A,B. CT scans of a chordoma with contrast. C. MRI of a chordoma. It is helpful for detecting multifocal lesions and monitoring for local recurrence. It is of limited value in the process of preoperative plan.

Biopsy Biopsy is of significant value to the definitive surgical intervention. The purpose is to yield a valid tumor diagnosis (benign vs. malignant), tumor grade (high vs. low grade), and the specific tumor type. The most commonly used technique is core needle biopsy. Open biopsy is not needed in most circumstances. The biopsy with a posterior midline entry portal at the appropriate level is most commonly performed. Biopsy should be well planned and follow established guidelines, such as incision placement within the line of eventual resection, thus minimizing contamination of normal tissues.

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FIG 6 • Angiograph of a chordoma patient showed blood supply before (A) and after (B) embolism of the tumor.

SURGICAL MANAGEMENT Preoperative Planning Careful review of every preoperative imaging including x-ray, CT, MRI, and angiography is crucial to formulate a surgical plan and evaluate the indications and risks. Upper extent of the resection should be well determined to achieve an accurate resection. The goal is to save as many sacral nerves as possible with good margins. Because the coccygeal tip could be easily exposed during operation and the exposure will not compromise the surgical margin, one recommended way of accurate resection is to measure the distance between the coccygeal tip and the level of sacral osteotomy based on the sagittal CT or MRI. Arterial embolization is recommended within 12 to 24 hours before surgery. The vessels that were selectively embolized P.185 mainly include the internal iliac, the lateral sacral, the iliolumbar, and the median sacral arteries. These vessels were identified by angiography and usually embolized by Gelfoam. Anesthetic techniques including controlled hypotension and controlled low temperature may be used to control the intraoperative blood loss for large and high-level sacral tumors. It is never wrong to get enough blood well prepared including red blood cell, plasma, and platelet. An alternative route of blood transfusion and fluid replacement is essential to the surgery. It is important to keep monitoring the estimated intraoperative blood loss and maintain adequate communication with the anesthetist. It is suggested that oral antibiotics are given 24 hours before surgery and cleaning enema is done 12 hours before surgery. In addition, at the time of surgery, all patients should have a Foley catheter and a rectal tube placed to provide protection for ureter, bladder, and rectum during operation. Intensive care unit (ICU) reservation should be considered. Appropriate communications with urologists and general surgeons are important if there is colon or bladder involvement.

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FIG 7 • A. Posterior position with Y-shaped approach. B. Posterior position with transversely placed H-shaped approach. C. Lateral position with an extended McBurney incision. Everything that might be needed during operation, including internal fixation materials, disposable hemostasis device, and other implants, should be well prepared. Possible image fusion of CT with MRI and subsequent detailed design of surgery should be performed if computer navigation-assisted surgery is planned.

Positioning Patient is placed in the prone position for the posterior approach. Patient is placed in the lateral position for the anterior-posterior approach (combined abdominosacral approach).

Approach The posterior approach: A longitudinal incision is performed through the midline from L5 to the coccyx. If the tumor is quite large, one or two transversal incisions could be added and the entire incision simulates a Y (FIG 7A) or a transversely placed H (FIG 7B). http://e-surg.com

The anterior-posterior approach (combined abdominosacral approach): It is a combination of the posterior incision and an extended McBurney incision, which starts from the lateral lowest rib and ends at the top of the pubic tubercle (FIG 7C). P.186

TECHNIQUES ▪ Sacral Tumor Resection via the Anterior-Posterior Approach The patient is placed in the lateral position (combined abdominolateral sacral position). Usually, the left side is up, but this may be revised depending on the soft tissue component of the tumor lateral to the sacrum. Anterior Approach An extended McBurney incision is performed first. Through this incision, the retroperitoneal space is explored by dissecting the abdominal wall musculature. The abdominal contents are pushed to the contralateral side of the abdomen. The ureters should be well protected during this process. Then, the abdominal aorta, the iliac vessels, and the median sacral vessels are exposed. In most cases, schwannoma could be excised with only this incision. This incision makes it possible to reduce the risk of bleeding by ligating the internal iliac artery of the same side and temporarily block the aorta. To ligate the median sacral vessels. The median veins are accompanied by the sacral nerve, and in front of the sacrum, they anastomose with each other to form the presacral venous plexus. It is suggested that suture ligation of the presacral venous plexus should be right above the sacral resection level. Then the venous plexus below the resection level is resected together with the sacrum. Through this management, excessive blood loss is usually avoided. When large tumors extend anteriorly into the pelvis, careful blunt dissection of tumors from the vital vessels is essential via this incision to avoid unnecessary vessel injuries and excessive blood loss. For those complex dumbbell schwannomas, if the osseous outlet is not big enough to resect the tumor in one piece via one incision, it is recommended to resect the tumor in the sacrum via the posterior incision first, while the tumor out of the sacrum should be well protected with gauze. For total sacrectomy, to free the anterior surface of the first two sacral vertebrae, because their complete resection involves considerable difficulty, S1-S3 nerve roots are cut off ventrally and the accompanying arteries and veins should be ligated. There are some arteries and veins on the surface of the sacroiliac joint, going up from below. These vessels should be ligated as well to avoid uncontrolled bleeding when performing the osteotomy of sacrum posteriorly. It is not easy to disarticulate the sacroiliac joint. So it is recommended that the ventral sacroiliac osteotomy is performed 1.5 cm laterally away from the joint. A deep groove is made with high-speed burr in the ventral sacrum. After the dorsal cortex of the sacrum is broken, the sacrum is divided finally and the tumor is removed en bloc. It is essential to protect the gluteal vessels and the sciatic nerve while working in the greater sciatic notch. If there are dense adhesions between the rectum and the anterior surface of the sacrum, the rectum should be resected with the sacrum. Posterior Approach The posterior incision starts from the lumbar spinous process and extends to 3 cm above the coccyx. However, the incision could be modified as a transversely placed H or Y. In the presence of a previous open biopsy, an elliptical incision should be made to get the entire biopsy track resected. http://e-surg.com

The incision is carried down to the deep fascia, and then the flaps are raised beyond the posterior superior iliac spine. The fibers of the gluteus maximus are divided along the sacral edge below S3 and the lumbodorsal fascia above S3. The lumbodorsal fascia is longitudinally open and a transversal incision is done at S3 level to expose and push the erector spinae muscles laterally. After the soft tissue is removed from the surface of the coccyx, the coccyx is exposed. Sacral Osteotomy The sacrum is marked with electrotome by measuring the distance between the coccyx and the preoperatively planned sacral osteotomy level (TECH FIG 1A,B). The gluteus maximus muscles are cut off 1 cm away from the insertion in the sacrum (TECH FIG 1C,D). The vessels in the gluteus muscles should be ligated carefully. If the erector spinae muscles are not involved, they are detached from the insertions in the sacrum and pulled proximally. However, if they are involved, they are cut at the level of the sacral resection level, not the insertions. After the ligaments are cut off from the ventral and bilateral aspects of the coccyx (TECH FIG 1E,F), some yellow adipose tissue is present in front of the sacrum. By pushing the adipose tissue anteriorly, some space is saved to cut the insertions of the pelvic floor muscle in the sacrum. Then the sacrotuberous ligament can be touched anterolateral to the sacrum and cut off subsequently. The sacrospinous ligament can be touched a little upper, accompanied by some vessels from the front. The vessels should be ligated when cutting off the sacrospinous ligament. Then the piriformis are exposed. Only some of the piriformis can be cut off because some of the muscles are hidden behind the sacroiliac joint (TECH FIG 1G,H). The sacroiliac ligaments are cut off until the lower rim of the sacroiliac joint. Some wet gauzes are applied in the presacral space to bluntly dissect the pseudocapsule of the tumor from the rectum. Following division of the anococcygeal raphe, gentle, blunt finger dissection is performed for a short distance on the anterior surface of the bowel until the level of the transabdominal dissection is reached. After the dissection is finished, wet gauze pads are used to protect the viscera. The electrotome is used to expose the back aspect of the sacrum. After the sacral osteotomy level is confirmed, the dorsal sacral nerves below the osteotomy level are divided. It is important to save the preserved nerves above the osteotomy level and ligate the vessels that are accompanying the nerves. The posterior foramen is enlarged by removing some of the upper and lower bone around the foramen with varied sizes of maxillary punch cutting forceps. Then the nerve roots and the dura are clearly exposed. The right upper nerve root is anterolateral to the present nerve root, and the right lower nerve root locates inside the present nerve and outside the dura. The dural sac is cut off and ligated caudally at this level as well as the lower nerve roots (TECH FIG 1IL). P.187 Through the open window of the posterior foramen, the anterior foramen could be identified ventrally. One http://e-surg.com

nerve dissector is placed between the anterior foramen and the sacral nerve so the lateral sacrum is safely removed horizontally until the level of ilium. The osteotomy is done from the bottom up in the ilium side of the sacroiliac joint to meet the previous osteotomy. At this point, only the sacrum body is still connected. Two nerve dissectors are placed between the anterior foramen and the sacral nerve. The anterior cortex of the sacrum is exposed by removing the cancellous bone with small curette. Then it is broken by an osteotome very carefully (TECH FIG 1M,N). It is essential not to cut through the cortex of the sacrum to avoid unnecessary bleeding of the anterior soft tissue. The anterior soft tissue is detached and ligated with hemostatic forceps while pulling the resected but still connected sacrum caudally. The insertion of the rectal ligament in the ventral sacrum is cut off after turning the sacrum over. The sacral nerves below the osteotomy level are resected in front of the anterior foramen. However, it is encouraged to anastomose the sacral nerves above S3 from the anterior foramen to the nerve ends at the osteotomy level. Nerve functions are expected to recover in a way. Then the sacrum with tumor is removed en bloc (TECH FIG 1O,P). Wound Closure After meticulous hemostasis, the wound is then irrigated and two closed-system drainages are used. The erector spinae muscles and gluteus maximus are sutured together. Finally, the incisions are closed in a routine fashion.

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TECH FIG 1 • A,B. If there is no navigation system available, the sacral osteotomy level is suggested to be marked with an electrotome before further procedures are taken. C,D. The gluteus maximus muscles are cut off 1 cm away from the insertion in the sacrum. The biopsy track should be resected together with the tumor. (continued) P.188

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TECH FIG 1 • (continued) E,F. The ligaments connecting the coccyx and others are cut off ventrally and bilaterally. G,H. Some of the piriformis are exposed and subsequently divided. I,J. The dural sac should be cut off and ligated carefully to avoid unnecessary leakage of cerebrospinal fluid. (continued) P.189

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TECH FIG 1 • (continued) K,L. The root nerves should be well protected when ligating the dural sac and cutting the sacrum. M,N. The anterior cortex of the sacrum is very carefully broken by an osteotome. Potential excessive bleeding is due to vessels in the soft tissues of the anterior surface of the sacrum. O,P. After the sacrum with tumor was removed, the saved sacral nerves and some anterior yellow presacral tissues were clearly seen. P.190

▪ Computer-Assisted Navigation in Sacral Tumor Resection The posterior incision starts from L5 and extends to the coccyx (TECH FIG 2A). The erector spinae muscles and the gluteus maximus muscles are adequately exposed laterally to the sacroiliac joint. The patient tracker is placed relatively far away from the tumor (ie, the ilium, the proximal spinal process). It emits infrared light, from which the navigation system determines where the tumor and the surrounding osseous anatomic structures are (TECH FIG 2B-D). Involvement of the erector spinae muscles and gluteus maximus is evaluated on preoperative imaging. If no, the image-to-patient registration could be pointbased (sometimes surface-based). After raising the http://e-surg.com

flap of erector spinae muscles and the gluteus maximus muscles, the spinal process and vertebral are exposed, which serve as the anatomic landmarks for registration. Surgeons are required to specify the positions of the paired points and feed this information into the system for calculation of the transformation matrix. After registration, it is important to verify the accuracy of registration by placing a navigator tool over the exposed topographic landmarks. If yes, the image-to-patient registration would be Iso-C based. The erector spinae muscles and gluteus maximus are cut off 1 to 2 cm away from the soft tissue mass. So those anatomic landmarks used in point registration are not exposed. Images were acquired by Iso-C three-dimensional (3-D) C-arm with automated orbital rotation of 190 degrees. The images were reconstructed in processor unit of Iso-C and transferred automatically to computer workstation. Preoperative CT/MRI in Digital Imaging and Communications in Medicine (DICOM) format is imported to the navigation system. Fusion of CT/MRI with Iso-C is performed using “surface matching image correlation,” and this automatically registers the bone with MRI/CT (TECH FIG 2E). The fused images are then ready for 3-D navigation procedures. The sacral osteotomy is guided by the computer-assisted navigation system. After the en bloc resection, the navigation system could be used to verify if the surgical margin is adequate by placing a navigator tool over the remaining sacrum (TECH FIG 2F). Then, after meticulous hemostasis, the wound is irrigated and closed-system drainages were used. The incision is closed in a routine fashion.

TECH FIG 2 • A. The Stryker computer navigation system. The patient was laterally positioned to facilitate the navigation process. The surgeon knows exactly where the tumor and the surrounding structures are via the system. Preoperative CT (B) shows the bone destructions very well and MRI (C) demonstrates the involved soft tissues. D. The good points of both CT and MRI are united when the imaging fusion technique is applied. (continued) P.191 http://e-surg.com

TECH FIG 2 • (continued) E. Preoperative surgical plan with detailed sacral resection design. F. After the tumor was removed, the navigation was used to verify the accuracy of the resection. In part B to D, the blue arrow indicates the bone margin of the tumor while the red arrow indicates the soft tissue margin of the tumor. P.192 Total Sacrectomy and Screw-Rod System Reconstruction Surgical plan is well planned based on CT and MRI, and the surgery is practiced preoperatively on sawbones (TECH FIG 3A-D). Navigation system is encouraged to facilitate the accurate resection and reconstruction as well (TECH FIG 3E,F). The patient is in the prone position with the posterior approach. The posterior incision extends from L3 to the coccyx. The posterior iliac crests, greater sciatic foramina, and sciatic nerves are exposed bilaterally as well as the L3-L5 spinal processes, facet joints, and transverse processes. After L5 laminectomy is done, the sacral nerve roots are then cut off, and the dural sac is ligated caudally. The sacroiliac osteotomy is performed 1.5 cm laterally away from the sacroiliac joint. Then the entire http://e-surg.com

sacrum with the tumor is removed en bloc as described previously (TECH FIG 3G). Two vertical L-shaped rods are positioned bilaterally in a manner allowing fixation to the L4-L5 pedicles on each side (TECH FIG 3H). One cross-connecting rod is used to secure the vertical rods to each other. Two screws in each side are placed to fix the iliac bones to each other and thereby prevent axial rotation of the lumboiliac union (TECH FIG 3I-L).2

TECH FIG 3 • A. Preoperative CT scan shows S5 involvement by malignant tumors. B. MRI shows the malignant tumor involvements more clearly. Total sacrectomy was planned. C. The posterior view of the sacrum shows the bone destruction in the sacrum and the planned screw in S4-S5. D. Two screws were preoperatively planned to nail the iliac bones to strengthen the sacroiliac joint stability. (continued) P.193

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TECH FIG 3 • (continued) E. Navigation was used to design the resection of the tumor. F. Navigation was used to nail the screw in the spine as well. G. After the tumor was removed, the remaining S1 nerve could be clearly seen. H. How the screw and rod was used to construct the sacroiliac joint stability. AP (I) and lateral (J) views of the resected entire sacrum with tumors. (continued) P.194

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TECH FIG 3 • (continued) AP (K) and lateral (L) postoperative radiographs.

PEARLS AND PITFALLS Preoperative

▪ Careful review of preoperative imaging studies, well-planned surgical design, and adequate preoperative preparations are crucial to the success of surgery. ▪ Embolization within 24 hours before surgery is significant in minimizing blood loss during surgery. Selective embolization and avoiding embolization of superior gluteal artery are helpful to prevent flap necrosis.

Intraoperative

▪ The posterior midline approach is the most common approach for sacral tumor resection. If the tumor is pretty large, two transversal incisions could be added to formulate a transversely placed H incision. The flap should be raised deep into the deep fascia to reduce risks of necrosis. ▪ If the tumor is well circumscribed in the sacrum and the erector spinae muscles are not involved, the cavity after tumor resection may be filled with these muscles. ▪ The insertions of the gluteus maximus, the piriformis, the sacrotuberous ligament, and the sacrospinous ligament are vulnerable to be involved by tumors. It is recommended to cut those structures at least 1 cm away from the insertions to ensure adequate surgical margin and thereby reduce the risks of local recurrences. ▪ There is a layer of loose tissue in the presacral area, from which the rectum could be easily bluntly detached to avoid unnecessary injury.

Postoperative

▪ Efficient drains are securely kept in place until 24-hour drainage is less than 20 mL because a large hematoma may develop in the cavity and result in severe infections. The position of lying down for long periods of time should be avoided to prevent flap necrosis. ▪ Vital signs as well as drainage should be closely monitored postoperatively. ▪ A heavy blood loss should be considered when one or more of the following happen: rapidly increased drainage during a short period of time, abdominal distension with dull percussion sounds, symptoms of shock, and progressively decreased hemoglobin. ▪ Fluid therapy, blood transfusion, temporary clamping of the drainage tube, emergency angiography, and embolization are possible managements for blood loss. Surgical exploration is not recommended due to its high risks for further bleeding and infections. ▪ The cavity easily gets infected. Skin necrosis and wound infections should be closely monitored. Early débridement and closure are usually associated with a better outcome.

POSTOPERATIVE CARE Regular repositioning is required to prevent flap necrosis if the patient is supine postoperatively. Lateral position should be applied once the patient has stable vital signs. Patients should stay in the ICU to get the vital signs and the drainage closely monitored. Special attention http://e-surg.com

should be given to the observation of possible heavy postoperative bleeding. Continuous perioperative intravenous antibiotics are continued until the drainage is less than 20 mL and the tubes are removed. The patient may begin ambulation 10 to 14 days postoperatively if no reconstruction surgery is performed. However, P.195 progressive ambulation is not encouraged until 4 to 6 weeks postoperatively if reconstruction surgery is performed. All postoperative patients should have a sacral radiograph and CT scan as the baseline for the possible followup comparisons (FIG 8). Serial evaluations of the specimen are used to verify whether the surgical resection matches the preoperative design. (FIG 9)

OUTCOMES Todd et al4 retrospectively analyzed the bowel and bladder function in 53 patients with major sacral resection. In patients who had bilateral S2-S5 nerve roots sacrificed, all had abnormal bowel and bladder function. In patients who had bilateral S3-S5 resection, normal bowel and bladder function was retained in 40% and 25%, respectively. In patients who had bilateral S4-S5 resection, with preservation of the S3 nerves bilaterally, normal bowel and bladder function was retained in 100% and 69%, respectively.

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FIG 8 • Postoperative anteroposterior (AP) (A) and lateral (B) radiograph and coronal (C) and sagittal (D) CT scans. In patients who had asymmetric sacral resections, with preservation of at least one S3 nerve root, normal bowel and bladder function was retained in 67% and 60%, respectively. In patients who had unilateral sacrectomy, in whom the contralateral sacral nerves were preserved, normal bowel and bladder function was retained in 87% and 89%, respectively.

COMPLICATIONS Intraoperative excessive blood loss is the most common complication. It is believed that angiography and subsequent embolization could significantly reduce the intraoperative blood loss, especially for those sacral tumors with high risks of mortality (ie, high-level or pretty large). Infection is another significant complication, and it is devastating when any implants are placed. Use of antibiotics by combinations during the perioperative phase is extremely important. Preoperative bowel preparation is also necessary. P.196 http://e-surg.com

FIG 9 • A. The formalin-fixed specimen was shown in four pictures. The posterior view of the sacrum showed there is no tumor exposed posteriorly. B. The anterior view of the sacrum showed there is no tumor exposed anteriorly. C. The sagittal view of the split specimen showed the resection of the sacrum was well performed. D. The axial view of the specimen showed the margin of the resection was macroscopically negative. Wound problems including infections, skin or muscle necrosis, nonhealing wounds, and wounds dehiscence are very challenging complications. The large cavity after resection, lacking muscles covering the wound, and possible hematoma in the wound are known risk factors of infections. Rectal injury during sacral tumor resection has been reported in the literature. The reasons could be either direct damage to the rectum or compromised blood supplies to the rectum. The rectal necrosis usually aggravates the infections. Nerve injury is a common complication, especially when the nerve is involved or the tumor has locally recurred. Special attention should be given to the sciatic nerve when the tumor is very large with extensive soft tissue involvement. The leakage of cerebrospinal fluid is a rare complication. No ligation after cutting off the dural sac and http://e-surg.com

being hard to ligate it in recurred high-level sacral tumors are the main two possible reasons, which should be clinically paid more attention to.

REFERENCES 1. Fourney DR, Gokaslan ZL. Current management of sacral chordoma. Neurosurg Focus 2003;15(2):1-5. 2. Gokaslan ZL, Romsdahl MM, Kroll SS, et al. Total sacrectomy and Galveston L-rod reconstruction for malignant neoplasms. Technical note. J Neurosurg 1997;87(5):781-787. 3. Hugate RR, Dickey ID, Phimolsarnti R, et al. Mechanical effects of partial sacrectomy: when is reconstruction necessary? Clin Orthop Relat Res 2006;450:82-88. 4. Todd LT, Yaszemski MJ, Currier BL, et al. Bowel and bladder function after major sacral resection. Clin Orthop Relat Res 2002; (397):36.

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Chapter 18 Overview of Pelvic Resections: Surgical Considerations and Classifications Ernest U. Conrad III Vincent Ng Jason Weisstein Jennifer Lisle Amir Sternheim Martin M. Malawer

BACKGROUND The pelvis is a relatively common anatomic location for metastatic and primary musculoskeletal tumors. Surgical resection is more challenging in the pelvis than in other locations because of the complex anatomy and the proximity to vital abdominal viscera and major blood vessels and nerves. Making decisions about surgical resectability of a tumor involves the assessment of possible osseous or neurovascular involvement, in addition to the possible involvement of adjacent viscera (ie, bowel, ureter, and bladder). Therefore, preoperative evaluation and extensive imaging are critical. Osseous resection and reconstruction usually are carried out adjacent to major nerves, beneath the iliac vessels, or adjacent to the bladder or bowel. Tumor surgery around the pelvis has the highest rate of complications, infections, and mechanical failure of all anatomic sites.

ANATOMY Pelvic Nerves Sciatic Nerve The sciatic nerve arises from L4, L5, S1, S2, and S3. The nerve emerges from the pelvis through the greater sciatic notch inferior to the piriformis muscle and enters the thigh lateral to the ischial tuberosity. In 10% of patients, the sciatic nerve penetrates the substance of the piriformis muscle. The sciatic nerve is accompanied by the inferior gluteal artery. It is essential to protect the sciatic nerve early in most procedures. Inside the pelvis, the nerve should be identified distally at the greater sciatic notch. Proximally, it should be picked up below the psoas muscle. The sciatic nerve is formed at the junction of the lumbar sacral plexus where these two trunks come together. Great care must be taken, as the nerve exits the pelvis at the level of the greater sciatic notch, not to injure the accompanying inferior and superior gluteal nerves and arteries because these supply the abductors as well as the gluteus maximus muscle. The gluteus maximus muscle is essential for closure of most pelvic resections. Femoral Nerve The femoral nerve arises from posterior divisions of the ventral rami of L2 and L3 and passes inferolaterally between the psoas and iliacus muscles. It passes over the superficial iliacus muscle to enter the proximal thigh underneath the inguinal ligament, just lateral to the superficial femoral artery. This nerve is almost always preserved during pelvic resections. It should be identified early during most procedures. The femoral nerve is identified in the space between the iliacus and psoas muscles as they exit the pelvis. The femoral nerve lies just below the fascia, bridging the interval between the two muscles, lateral to the femoral artery and vein. Obturator Nerve The obturator nerve, formed from the anterior branches of L2, L3, and L4, is the largest nerve formed from anterior divisions of the lumbar plexus. The nerve descends thru the iliopsoas muscle and courses distally over the sacral ala into the lesser pelvis, lying lateral to the ureter and under the internal iliac vessels. It then traverses the obturator foramen into the medial thigh, under the superior pubic ramus, dividing into anterior and posterior branches. This nerve is routinely transected during pelvic floor resections (type III) due to its intimate proximity to the tumor. Lumbar Plexus Sensory Nerves The iliohypogastric (L1), ilioinguinal (L1), genitofemoral (L1, L2) and lateral femoral cutaneous nerves, which arises from L2 and L3, travel downward laterally along the iliopsoas muscle, pass underneath the lateral aspect of the inguinal ligament, and pass just distal and medial to the anterior superior iliac crest to innervate the anterolateral thigh. This nerve is sacrificed during most pelvic surgical procedures.

Pelvic Vessels

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Aortic Bifurcation Descending the abdomen to the left of the vena cava, the aorta bifurcates at the level of L4 into common iliac vessels at the level of L4-L5. The common iliac bifurcates into internal and external iliacus vessels at the level of S1, the ala sacralis. The level of these bifurcations may vary, especially if the vessels are pushed by a large adjacent tumor mass (FIG 1A). It is essential to identify two levels of bifurcations before any ligation: the aortic bifurcation and the common iliac bifurcation. Even the best surgeons have ligated the wrong vessels due to distorted anatomy. Such a misstep is especially possible with tumors that cross the midline. Preoperative evaluation with angiography is required for a comprehensive evaluation. Common Iliac Artery The common iliac artery must be identified early to correctly identify the aorta as well as the internal iliac (hypogastric) P.198 P.199 artery (FIG 1B). To the surgeon, the major anatomic features of the common iliac artery are as follows:

FIG 1 • A. The bony pelvis and its relation to the major blood vessels, nerves, and visceral organs. B. Surgical illustration demonstrating critical vascular anatomy of the pelvis. Specific attention must be paid regarding common iliac and internal/external iliac vessels and requires achieving vascular control during pelvic resection. (A: Courtesy of Martin M. Malawer.) No arterial branches arise from the artery (although the common iliac vein does have a major branch joining in, the iliolumbar vein). The bifurcation of the common iliac artery into the external and internal iliac arteries is at the exact level at which the ureter crosses on the adjacent peritoneal surface. The ureter is routinely identified at this location early in the retroperitoneal dissection. Failure to achieve vascular control of the common external or internal iliac artery or vein can result in uncontrolled blood loss as a consequence. External Iliac Artery The external iliac artery contributes to the inferior epigastric artery and extends distally, as the superficial femoral artery, into the femoral triangle, where it is a useful landmark in identifying neighboring structures.

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Internal Iliac Artery The internal iliac (hypogastric) artery descends from the lumbosacral articulation to the greater sciatic notch and branches into several arteries. The internal iliac artery and vein often are difficult to identify or ligate. The internal iliac artery lies on top of its vein, which often is large and is easily injured. The hypogastric vessels are routinely ligated in performing modified hemipelvectomies as well as many pelvic resections. Anterior branches The obturator artery exits the pelvis via the obturator canal (beneath the superior pubic ramus). The inferior gluteal artery curves posteriorly between the first and second or second and third sacral nerves, then runs between the piriformis and coccygeus muscles or through the greater sciatic foramen into the gluteal region below the piriformis muscle. Posterior branches The iliolumbar artery ascends posterior to the obturator nerve and external iliac vessels to the medial border of the psoas. It then divides into the lumbar branch, to the psoas and quadratus lumborum muscles and to the spinal cord, and an iliac branch, to the iliac, gluteal, and abdominal musculature. The iliac branch often is ligated during surgery. The superior gluteal artery runs posteriorly between the lumbosacral trunk and first sacral nerve and leaves the pelvis through the greater sciatic foramen superior and posterior to the piriformis muscle. Great care must be taken to preserve the gluteal vessels and nerves when performing types I and II pelvic resections. Ureter The ureter originates from the renal pelvis at the level of L1 and courses in the retroperitoneum to the medial surface of the psoas major muscle, crossed by spermatic or ovarian vessels. The ureter crosses from lateral to medial on the surface of the peritoneum at the level of the common iliac bifurcation. This is a good landmark to identify the ureter during the initial retroperitoneal dissection. The ureter then courses medially at the level of the sciatic notch to insert into the trigone of the bladder. Corona Mortis The corona mortis is an anastomosis of the external iliac, inferior epigastric, and obturator vessels located in the retropubic region approximately 3 cm from the symphysis pubis. Laceration during an ilioinguinal approach can lead to extensive bleeding. The retroperitoneal space between pubis and bladder is called the space of Retzius. Inguinal Canal The anatomic confines of the inguinal canal are described as 4 cm from the deep inguinal ring to the subcutaneous ring. This “deep ring” is the “direct” inguinal space originating lateral to the epigastric vessels. Hesselbach triangle is the “indirect” hernia space originating medial to the epigastric vessels. The inguinal contents vary by gender: In males, the spermatic cord contains the ductus deferens, testicular artery, pampiniform plexus, lymphatics, autonomic nerves, the ilioinguinal and genital branches of the genitofemoral nerve, the cremasteric artery and muscle, and the internal spermatic fascia. In females, the inguinal contents include the round ligament and the ilioinguinal nerve. The anterior inguinal wall is formed by the aponeurosis of the external oblique and internal oblique (lateral) muscles. The posterior inguinal wall runs medial to lateral and is formed by the reflected inguinal ligament, the inguinal falx, and the transversalis fascia. The superior or cephalic inguinal wall is formed by arched fibers of the internal oblique muscle and the transverse muscle of the abdomen. The inferior or caudal inguinal wall is formed by the inguinal and lacunar ligaments.

Boundaries The sciatic notch should be identified early in surgery, both internally and externally, to protect the sciatic nerve and gluteal pedicles. The superior cephalad margin of the pelvis is defined by the ilium and the rim of the great sciatic notch. The posterior margin of the pelvis is bounded by the piriformis muscle and the superior gluteal vessels and nerve. Posterior to the piriformis muscle, the internal pudendal vessels and nerve course medially off the sciatic nerve and the posterior femoral cutaneous nerve, anterior to the piriformis. Inferior margin: The sacrospinous and sacrotuberous ligaments are released during types I and II pelvic resections.

INDICATIONS Recurrent Benign Tumors

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Major pelvic resections rarely are performed for benign bony tumors. Occasionally, following multiple recurrences or when tumors are limited to either the superior or inferior pubic rami, pelvic resection is indicated. Such benign tumors include large solitary osteochondromas or any osteochondroma associated with multiple hereditary exostosis due to the high risk of secondary chondrosarcoma. Osteoblastoma occurring in the ilium or periacetabulum Giant cell tumors or aneurysmal bone cysts have a predilection for the superior pubic ramus and supra-acetabulum. P.200

Primary Malignant Osseous Tumors Osteosarcoma Five percent of all osteosarcomas occur in the pelvis. Partial pelvic resection or hemipelvectomy (amputation) is required, usually following induction chemotherapy. Ewing sarcoma About 25% of all Ewing sarcomas occur in the pelvis. Surgical resection is required. Adjuvant radiation therapy is recommended in treating pelvic Ewing sarcoma with surgical resection. Resection should be performed only following induction chemotherapy. Chondrosarcoma Chondrosarcomas are the most common primary malignant bony tumors of the pelvis. They often are much larger than plain radiographs indicate. Further imaging with magnetic resonance imaging (MRI) demonstrates the cartilaginous component of the tumor.

Metastatic Adenocarcinoma: Breast, Prostate, Renal, Lung, Colon Metastatic adenocarcinoma most commonly involves iliac or periacetabular sites. Most metastatic tumors to the pelvis are treated adequately with radiation therapy. Occasionally, there may be significant acetabular destruction with an impending pathologic fracture that requires surgical reconstruction. Renal cell carcinoma (hypernephroma) metastases are an exception. These metastases often require surgical removal, either by resection or by curettage and cryosurgery. Preoperative embolization always is required for these vascular tumors to avoid severe bleeding during surgery.

Soft Tissue Sarcomas Retroperitoneal soft tissue sarcomas are more common than intraperitoneal sarcomas and must be evaluated carefully; preoperatively for gastrointestinal, genitourinary, vascular, or peripheral nerve involvement.

IMAGING AND OTHER STAGING STUDIES Plain Radiography Plain radiography (FIG 2) is of limited value in the assessment of pelvic girdle lesions. Images often are obscure and confusing. The pelvis, particularly the sacrum, is a difficult structure in which to recognize early bone lesions, and major bone lesions initially may be overlooked. For these reasons, there should be a low threshold for performing further imaging, especially for initial screening and the postoperative evaluation of reconstructions.

Computed Tomography and Magnetic Resonance Imaging As a general rule, both computed tomography (CT) and MRI are well indicated for the initial evaluation of most pelvic tumors. CT with intravenous contrast and three-dimensional reconstruction is the optimal technique for assessing the extent of bone involvement and destruction, the osseous anatomy, and the relation between the tumor and the major blood vessels of the pelvis (FIG 3). It is valuable for depicting any distortion of the pelvic anatomy and aiding in the evaluation of the tumor to decide whether it is resectable. Chest CT is essential for staging purposes in evaluation for pulmonary metastases. MRI with contrast is critical for imaging soft tissue (ie, vessels, nerve, muscle) and osseous involvement. MRI is the optimal modality for imaging soft tissue and marrow involvement. It is attractive for assessment of osseous disease and sacral involvement and may be helpful with the serial assessment of neoadjuvant (induction) therapy.

Bone Scanning Three-phase bone scan is used to rule out systemic metastasis and to assess the focal osseous involvement and tumor vascularity in the initial flow phase. A decrease in vascularity after induction chemotherapy may indicate response to treatment.

Angiography Angiography is mandatory for determining the distal vascular anatomy that often is distorted by large pelvic tumors (FIG 4). It is essential to

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determine the level of the various bifurcations preoperatively and to rule out vascular involvement by the tumor. Embolization of the tumor blood supply before surgery is helpful in minimizing blood loss, especially with vascular tumors and tumors with sacral involvement.

Venography The pelvic veins always are much larger than their arterial counterparts. Preoperative venography is used to rule out tumor (mural) thrombi, a common finding in chondrosarcomas and osteosarcomas. Their presence may change the planned surgical approach. Postoperative venous Doppler is recommended routinely in all postoperative pelvic resection patients.

Fluorine-18 2-fluoro-2-deoxy-D-glucose-Positron Emission Tomography Fluorine-18 2-fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) may be useful in assessing the “grade” of malignancy, evaluating response to neoadjuvant chemotherapy, and monitoring for local recurrence. Positron emission tomography (PET) combined with CT or MRI is useful for evaluating tumor response. PET-CT scans are useful in early detection of small recurrences. It plays only a minimal role in preoperative planning in determining the extent of surgical resection.

Biopsy The purpose of biopsy is to yield a valid tumor diagnosis (benign vs. malignant), tumor grade (high vs. low grade), and tumor subtype (eg, leiomyosarcoma vs. malignant fibrous histiocytoma). Biopsies may be performed by either open or needle technique. Because open biopsy for pelvic tumors is an extensive procedure, needle biopsy—especially CT-guided needle biopsy—is recommended initially for both metastatic and primary pelvic tumors. P.201

FIG 2 • A. Plain radiograph revealing a large lytic lesion (arrowheads) of the right periacetabular region. On the basis of this radiograph, it appears that the cortices are intact. B. Anteroposterior (AP) plain radiograph of the pelvis, read as normal. C. Plain radiograph revealing a cartilage-forming lesion in the left ilium. On the basis of this study alone, it seems that this is an intraosseous lesion. Plain radiographs performed 24 hours after a CT-guided core needle biopsy of a sacral lesion (note the coil; D) and after 6 weeks (E).

FIG 3 • A. CT showed extensive bone destruction and extension of the tumor to the pelvis and the right gluteal region. B. CT of the pelvis revealed a large destructive lesion of the sacrum. C. CT shows an extensive tumor on the medial aspect of the ilium with destruction of the inner

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table and extension of the pelvis. (A,B: Courtesy of Martin M. Malawer; C: From DeVita VT, Hellman S, Rosenberg SA, eds. Cancer: Principles and Practice of Oncology, ed 5. Philadelphia: Lippincott Williams & Wilkins, 1997:1789-1852.) P.202

FIG 4 • Preoperative angiography and embolization of the metastatic lesion shown in FIG 3A. (Courtesy of Martin M. Malawer.) Biopsy technique should follow established guidelines for incision placement within the line of eventual resection, minimize contamination of normal tissues (eg, achieve adequate hemostasis at biopsy closure), and retrieve an adequate specimen for frozen section diagnosis. The biopsy should avoid the gluteal and groin areas because they are potential sources for flaps for skin closure after anterior and posterior hemipelvectomy, if necessary. The biopsy incision can also be placed transversely, in the line of the iliac or inguinal incision.

Anatomic Considerations Evaluation of the full anatomic extent of a pelvic tumor cannot be based on a single imaging modality. Combined data, gained from two or more imaging modalities, allow a realistic appreciation of the exact anatomic extent. Even when that information is available, however, the full extent of a pelvic tumor often is underestimated preoperatively. Review of any imaging study of the pelvis, because of the numerous anatomic details, must be performed very methodically. The authors review the structures from the back (midsacral region) and follow the pelvic girdle to the front (symphysis pubis), as described in the following paragraphs. Sacrum, Sacral Alae, and Sacroiliac Joint Most patients who undergo extended hemipelvectomy, which necessitates transection of the sacrum through the ipsilateral neural foramina, regain function of the gastrointestinal and genitourinary tracts. Adding a contralateral compromise of the sacral nerve root will create a severe dysfunction. Tumors that penetrate the sacrum and cross the midline are considered unresectable because of the involvement of bilateral sacral nerve roots (FIG 5). The tumor can be resected but the morbidity of bilateral sacral nerve root loss usually outweighs the questionable oncologic benefit from surgery. The common iliac vessels are just anterior to the sacral ala, and any cortical breakthrough by a tumor in that site may be expected to extend directly to the blood vessels. The sacroiliac (SI) joint is a key anatomic landmark. The major nerves and blood vessels are medial to it; therefore, any tumor or pelvic resection lateral to the SI joint may be expected not to violate the major neurovascular bundle. Tumor transgression through the SI joint should be documented prior to surgery by using the combination of CT, MRI, and bone scan.

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FIG 5 • High-grade chondrosarcoma of the right sacrum, ilium, and periacetabular region, encasing the ipsilateral sacral foramina. Wide excision would necessitate resection through the contralateral sacral foramina, resulting in an unacceptable functional impairment. (Courtesy of Martin M. Malawer.) Major Pelvic Blood Vessels and Structures The common iliac artery bifurcates along the sacral ala, and the ureter crosses the bifurcation on its ventral side. Large tumors around the sacral ala commonly displace and occasionally invade these structures. The mere presence of major blood vessel or pelvic viscus involvement by tumor is not an indicator of unresectability and demands preoperative planning. If necessary and curative resection is planned, both structures can be excised en bloc with the tumor and then can be repaired with a graft. However, when a complex resection (bony pelvis and viscus resection) is anticipated, the patient must be informed, and surgical assistance and necessary equipment must be prepared in advance. Sacral Plexus Current MRI imaging techniques cannot accurately identify nerve involvement by tumor. Clinical evidence of femoral, sacral, or sciatic nerve dysfunction usually suggests direct tumor involvement. In most cases, the presence and extent of nerve involvement is established only at the time of surgery. Sacral plexus invasion by tumor has the same significance in terms of resectability as tumor invasion of the sacrum; bilateral involvement is an indicator of probable unresectability. Sciatic Notch and Nerve The sciatic notch is the site of pelvic osteotomy in resections of the ilium or periacetabular region and in modified hemipelvectomy. CT establishes tumor extension to the sciatic notch, a tight space through which the sciatic nerve and superior gluteal vessels and nerve pass (FIG 6). The piriformis muscle, which divides the sciatic notch, is a key structure because the sciatic nerve exits the pelvis underneath it and the superior gluteal artery exits the pelvis above it. The patency of the superior and inferior gluteal arteries, which supply the gluteal vasculature, is established by angiography. Adequate blood supply of the gluteal region is a major preoperative consideration in flap design, and the artery must be P.203 preserved in any pelvic resection, if oncologically feasible. The artery is located only a few millimeters from the periosteum of the sciatic notch roof, and it should be dissected carefully.

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FIG 6 • The sciatic notch is a tight space through which the sciatic nerve and superior and inferior gluteal vessels and nerves pass. The sciatic nerve exits the notch underneath the piriformis muscle, and the superior gluteal vessels exit the notch above it. (Courtesy of Martin M. Malawer.) Ilium The inner aspect of the bone is covered by the iliacus muscle, which originates from the iliac crest. The iliacus is “pushed” by a growing bone sarcoma and serves as a major barrier to direct extension of tumor to the anatomic structures of the pelvis. Therefore, the iliacus can be used as an oncologic margin for resection. In contrast, metastatic carcinomas to the pelvis tend to invade the covering muscle layer early in their growth stage, and a surgical plane between the tumor and nearby structures cannot be easily defined (FIG 7). Although any pelvic organ can be infiltrated by a tumor, structures that are anterior and posterior to the flare of the muscle (ie, sacral plexus, sciatic notch and nerve, femoral vessels and nerve, bladder, and prostate) are at greater risk for direct tumor extension. Extension to Pelvic Viscera Direct involvement of a pelvic viscus by a pelvic girdle tumor is rare. Left-sided tumors are more likely to involve a component of the gastrointestinal tract because of its close proximity to the pelvic girdle at that point. A rectal tube is inserted preoperatively during any pelvic resection to facilitate identification of the rectum during dissection. Acetabulum and Hip Joint Wide resection of any bone tumor in the periacetabular region, unlike a resection of the ilium or the pubis, imposes a major impairment on the function of the hip joint. It usually necessitates en bloc resection of the proximal femur and a complex prosthetic reconstruction.

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FIG 7 • A. The iliacus muscle (arrowheads) is “pushed” by a growing bone sarcoma and serves as a barrier to direct extension of the tumor to the pelvic viscera. High-grade sarcoma of the left ilium “pushing” the iliacus muscle toward the midline. B. Metastatic carcinomas (arrows) to the pelvis tend to invade the covering muscle layer. (Courtesy of Martin M. Malawer.) Pubis The neurovascular bundle passes within the femoral triangle just superficial to the superior pubic ramus. Tumors extending to or arising from the pubic ramus are in close proximity to the femoral artery, vein, and nerve. In addition, the urethra passes straight underneath the symphysis pubis. Vulnerable structures such as a major blood vessel, nerve, or a viscus must be identified and mobilized before resection. By identifying and isolating crucial structures, the surgeon avoids iatrogenic injury during dissection. Establishing the relation of these vulnerable structures to the tumor allows the surgeon to decide whether to proceed with a limbsparing procedure or perform an amputation, make the necessary preparations for a vascular graft (if needed), and perform a safe resection.

SURGICAL MANAGEMENT Preoperative Planning Restaging Studies Preoperative planning is crucial to obtain an optimal oncologic and functional surgical result. Imaging studies are crucial in addressing the following questions: location and extent of the tumor, the type of pelvic resection that is necessary for adequate removal of the tumor, involvement of critical adjacent structures in the tumor mass (ie, ureter, aorta, inferior vena cava, bladder), and the type of reconstruction that can be achieved. Plain radiographs, CT scans, MRI scans, bone scans, and three dimensional-computed tomography (3-D-CT) P.204 angiographs are obtained to access the extent of osseous and soft tissue involvement in all anatomic planes. The status of crucial adjacent structures—bladder, colon, ureter, inferior vena cava, sacral alar, and possible lumbar extent—is reviewed. Using angiography and venography, preoperative embolization is considered, and anatomic distortion and vessel occlusion and venous thrombus are assessed. Consider the possible need for prophylactic ureteral stents if there is evidence of preoperative ureteral obstruction or displacement.

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Medical and anesthesia personnel are consulted to assess medical risk, preoperative laboratory studies, and transfusion needs (eg, prepare red blood cell count, cryo, platelets, and plasma). A risk of major blood loss during surgery is assumed, often equal to one total body transfusion (>7% body weight in kilogram). Bowel preparation before surgery and intensive care unit (ICU) reservation also should be considered. Orthotic brace is fabricated preoperatively for postoperative use. Colostomy planning and training must be considered if there is left colon involvement or large left-sided pelvic tumors, both of which can be detected preoperatively with contrastenhanced CT and colonoscopy. Appropriate prosthetic implants (eg, total hip replacement vs. saddle prosthesis), bone allograft, or other implants must be ordered.

Positioning At the time of surgery, all patients should have a Foley catheter and consider placement of a rectal tube. The rectum may be sutured around the rectal tube to avoid iatrogenic contamination during the operative procedure. During surgery, the surgeon may palpate the balloon of the Foley catheter in the bladder and the rectal tube through the wall of the rectum to assist in proper identification of these structures. This is especially helpful with large pelvic tumors, especially those on the left side. Type I resection (iliac-posterior): The patient is positioned in the lateral decubitus position with an anterior tilt to allow posterior access (FIG 8AD). Type II resection (periacetabular): The patient is positioned in the lateral decubitus position for access to both the anterior and posterior pelvis (FIG 8E,F). Type III resection (pelvic floor-anterior/obturator ring): The patient is positioned supine with the lower extremity flexed and abducted to provide exposure of the retroperitoneal space, the femoral triangle, the perineum, the symphysis pubis, and the ischiorectal space (FIG 8G-I).

FIG 8 • Type I pelvic (ilium) resection can be either partial (A), in which only part of the ilium is transected, or complete (B). Partial (C) and complete (D) type I resections. E. Type II pelvic (periacetabular) resections. Reconstruction was performed with a saddle prosthesis. F. Type II pelvic resection. (continued) P.205

FIG 8 • (continued) G-I. Type III pelvic (pubic) resection. These resections may include the superior pubic ramus (G), inferior pubic ramus, or both

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rami (H). I. Type III pelvic resection.

Approach The most useful approach to pelvic biopsy or resection is the utilitarian pelvic incision (FIG 9). All or part of the incision can be used for adequate exploration and resection of the majority of pelvic girdle tumors. The incision begins at the posterior inferior iliac spine and extends along the iliac crest to the anterior superior iliac spine. It is separated into two arms: One is carried along the inguinal ligament up to the symphysis pubis; the other turns distally over the anterior thigh for one-third the length of the thigh and then curves laterally just posterior to the shaft of the femur below the greater trochanter and follows the insertion of the gluteus maximus muscle. Reflection of the posterior gluteus maximus flap exposes the retrogluteal space, the proximal third of the femur, the sciatic notch, the sciatic nerve the sacrotuberous and sacrospinous ligaments, the origin of the hamstrings from the ischium, the lateral margin of the sacrum, and the entire buttock. Significant concern exists regarding the possible extracompartmental implantation of tumor cells following biopsy or resection of a pelvic tumor— procedures that are difficult to perform under optimal hemostatic conditions. Unnecessary biopsies must be avoided. If biopsy is indicated, the proper technique and a suitable approach must be chosen. The biopsy tract must be positioned along the line of the future utilitarian incision, remote from the major neurovascular bundle and the abductors. CT-guided core needle biopsy is considered to be an accurate and safe diagnostic tool in the diagnosis of musculoskeletal tumors and is the modality preferred by the authors. The utilitarian incision may be used for hemipelvectomy by continuing the distal portion of the primary incision posteriorly around and behind the thigh and bringing it anteriorly along the inferior pubic ramus to the symphysis, thus encircling the thigh but still allowing the large posterior flap to be used for primary wound closure. Type I Resection: Iliac Resection The incision for an iliac resection is ilioinguinal, following the iliac crest and curving posteriorly at the level of the SI joint. It then follows the length of the SI joint combined with a lateral incision to expose the outer portion of the ilium, sciatic notch, and retrogluteal space. Type II Resection: Periacetabular Resection A combination of an anterior retroperitoneal approach and lateral anterior incision along the femur that curves posteriorly is used for a periacetabular resection. A lateral, posterior-based fasciocutaneous flap, called a gluteal flap, is then raised. This permits easy access and visualization of the retrogluteal space: hip joint, sciatic notch, sciatic nerve, and ischium as well as the supra-acetabular area needed for the superior osteotomy.

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FIG 9 • The utilitarian pelvic incision. (Courtesy of Martin M. Malawer.) P.206 Type III Resection: Pelvic Floor and Pubic Region Three incisions are required for a resection of the pelvic floor and pubic region. The main incision is the retroperitoneal (ilioinguinal) incision to permit retroperitoneal exploration and mobilization of the major vessels and nerves. Two longitudinal incisions are required to develop a distal-based flap of the anterior thigh so as to expose the femoral triangle as well as the adductors attaching to the obturator foramen. One incision follows the perineal crease; the second begins at the lateral portion of the ilioinguinal incision at the level of the anterior superior iliac spine.

TECHNIQUES ▪ Type I: Iliac Posterior Resection The patient is placed in the lateral decubitus position with a posterior tilt. The utilitarian pelvic incision is used. Its ilioinguinal component is advanced medially to the symphysis pubis, and its posterior arm is brought to the level of the SI joint (TECH FIG 1A,B). All muscle attachments, with the exception of the iliacus and gluteus minimus and portions of the gluteus medius, which are resected en bloc with the tumor, are removed from the iliac crest. The abdominal wall musculature, the sartorius muscle, and the tensor fasciae latae muscles are transected from the iliac crest and reflected away from the ilium. The rectus femoris muscle remains intact. The iliotibial band is transected from its origin from the iliac crest and reflected posteriorly along with the gluteus maximus. Large fasciocutaneous flaps are raised and reflected medially and posteriorly. The plane between the iliacus and the psoas muscle is developed cautiously because the femoral nerve lies in that space. The psoas muscle and the femoral nerve are reflected medially, and the iliacus muscle is transected through its substance (TECH FIG 1C). The external iliac artery, which lies against the lower margin of the ilium, gives off no major branches along the inner table of the ilium; ligation of large blood vessels is not required, therefore, in type I pelvic resection. Most tumors of the ilium break through the outer table and

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push the gluteus medius muscle laterally. The gluteus medius muscle is transected through its substance, 2 to 3 cm distal to the inferior border of the tumor (TECH FIG 1D,E). It is important to try to save as much muscle belly as possible because that will be the major component in soft tissue coverage of the pelvic content and will be necessary for reconstruction of the abductor mechanism. Osteotomy of the ilium is performed using a malleable retractor, which is inserted through the greater sciatic notch, along the inferior border of the inner table, and out just underneath the anterior superior iliac spine, to protect the pelvic viscera (TECH FIG 1F). The ilium is transected as shown by the dotted line in the figure, P.207 P.208 leaving the origin of the rectus femoris muscle and the roof of the acetabulum intact. Osteotomy of the posterior aspect of the ilium is then performed; a malleable retractor is positioned through the greater sciatic notch, along the posterior border of the ilium, and parallel to the ipsilateral sacral ala (TECH FIG 1F, inset).

TECH FIG 1 • A. Incision and surgical approach. The entire utilitarian incision is used for type I resection. The posterior fasciocutaneous flap exposes the entire retrogluteal area: the sciatic notch, the sciatic nerve, the abductor muscles, and the hip joint. This approach provides a good exposure of the retroperitoneal space as well as the posterior retrogluteal area and permits a safe resection of the ilium. B. The ilioinguinal component is advanced medially to the symphysis pubis and posteriorly to the sacrum. (continued)

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TECH FIG 1 • (continued) C. Posterior exposure and muscle releases. The abdominal wall musculature is transected off of the iliac crest. The sartorius and tensor fasciae latae muscles are transected from their tendinous insertions and reflected distally. The rectus femoris muscle remains intact. Large fasciocutaneous flaps are raised and reflected medially and posteriorly. The iliotibial band is transected from its origin from the iliac crest and reflected posteriorly along with the gluteus maximus. D. Anterior (retroperitoneal) exposure. The retroperitoneal space is easily exposed and explored through the ilioinguinal component of the incision. The plane between the iliacus and the psoas muscle is developed with caution because the femoral nerve lies in that space. The psoas muscle and the femoral nerve are reflected medially, and the iliacus muscle is transected through its substance. The femoral nerve is preserved. E. Posterior exposure and release of gluteal muscles. The retrogluteal area is exposed. The gluteus maximus muscle is released from the iliotibial band and from the femur and reflected posteriorly. The sciatic nerve is identified and preserved. All of the remaining abdominal muscles are released from the wing of the ilium. The gluteus medius muscle is transected through its substance, 2 to 3 cm distal to the inferior border of the tumor. It is important to try to save as much muscle belly as possible. F. Supra-acetabular osteotomy and SI disarticulation. A malleable retractor is inserted through the greater sciatic notch, along the inferior border of the inner table, and out just underneath the anterior superior iliac spine to protect the pelvic viscera. The ilium is transected above the hip capsule, leaving the origin of the rectus femoris muscle and the roof of the acetabulum intact. Care is taken not to enter the hip joint. Inset: The SI joint is opened from within the pelvis. The iliac vessels must be mobilized and retracted before attempting to open the SI joint. (continued)

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TECH FIG 1 • (continued) G. Soft tissue reconstruction. The gluteus medius muscle is sutured to the abdominal wall musculature with the ipsilateral lower extremity in abduction. Dacron tape must be used to reinforce this reconstruction. The suture line also is reinforced by oversewing the tensor fascia lata and sartorius muscles. (Courtesy of Martin M. Malawer.) The most important component of soft tissue reconstruction is the attachment of the proximal rim of the gluteus medius muscle to the abdominal wall musculature. Even if the entire gluteus medius muscle was spared, the attachment of these two muscle groups, which are not anatomically connected, creates a significant tension, which can be reduced by placing the lower extremity in abduction. The suture line is reinforced with the tensor fasciae latae and sartorius muscles with 3-mm Dacron tape (TECH FIG 1G). Closure of the muscle layer must be meticulous because poor healing and wound dehiscence will expose the abdominal and pelvic contents and will be difficult to manage. Optional Reconstruction It is not necessary to reconstruct the resultant bony defect, although allograft reconstruction has been reported. For iliac osseous reconstruction, allograft should be thawed with permanent/tissue culture. Gram stain has a high rate of false positives and should be avoided. Cut the allograft after careful sizing and orientation and fix with a 4.5-mm reconstruction plate. Use intraoperative radiographs to confirm screw placement. Two deep soft drains (anterior and posterior) are placed deep to the fascial closure.

▪ Type II: Periacetabular Resection The patient is in the lateral decubitus position with posterior tilt to maximize anterior dissection. The utilitarian incision is used to expose both the anterior (internal) and posterior (extrapelvic) aspects of the pelvis. The ilioinguinal incision is used to develop the retroperitoneal plane, and the posterior gluteus maximus fasciocutaneous flap is used to develop the retrogluteal space. The iliac vessels are mobilized first, and the hypogastric artery is identified and ligated. The sciatic and femoral nerves are identified and protected. The level of osteotomy through the ilium is identified from within the pelvis, as are the superior pubic rami. Identification of the superior pubic rami requires mobilization of the external iliac and femoral vessels as they cross the ramus (TECH FIG 2). A large posterior myocutaneous flap is developed with the gluteus maximus muscle. The gluteus maximus muscle is detached from the iliotibial band and femur to enable it to be retracted posteriorly. This exposes the retrogluteal space: the ilium, sciatic notch, sciatic nerve, and hip joint. The ischium is identified through the posterior incision and is osteotomized above the level of the biceps femoris tendon insertion. Complete removal of the periacetabulum requires release of the sacrospinous ligament and some of the pelvic floor musculature. An ilioinguinal incision is used with a separate posterolateral hip incision for hip exposure and replacement, posterior column osteotomy, and exposure of the sciatic nerve. Three types of osteotomies may be used for periacetabular resection: supra-acetabular osteotomy, superior pubic ramus osteotomy, or ischial osteotomy. A total hip exposure is used to identify the sciatic nerve and posterior column. The procedure is begun with dissection of the external rotators

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and osteotomy of the femoral neck per total hip procedure. Cut the femoral neck at the standard neck length (1.0 cm proximal to the lesser trochanter). Incise the hip capsule peripherally with dissection of the sciatic nerve proximally to the sciatic notch. The anterior and posterior columns are exposed to allow osteotomy of the acetabulum. Supra-acetabular and ischial osteotomy requires careful exposure and retraction of the sciatic nerve and gluteal vessels. Composite Allograft Acetabular Reconstruction after Type II Resection Several choices are available for reconstruction following a type II resection: composite allograft, saddle reconstruction (The Link Prosthesis, LINK® Endo-Model® Saddle Prosthesis Rockaway, NJ), partial pelvic prosthesis (Stryker Periacetabular Reconstruction Prosthesis [PAR], Mahwah, NJ), various reconstruction rings with large phalanges, and ischiofemoral arthrodesis. Each has unique techniques, complications, functional deficits, and results. P.209

TECH FIG 2 • A. Plain radiograph showing an extremely high-grade malignant fibrous histiocytoma arising from the superior and inferior pubic ramus involving the entire obturator foramen, pelvic floor, and medial and supra-acetabular aspect of the acetabulum (solid arrows). B. Gross specimen following type II or type III pelvic resection. C. Gross specimen following a complete internal hemipelvectomy (type I/type II/type III pelvic resection). D. Radiograph of the resected specimen showing complete involvement of the hemipelvis. The defect superiorly was created by an open biopsy. E. Gross specimen of a combination type II or type III pelvic resection. F. Gross specimen following a type III pelvic resection. A large tumor mass is seen arising from the obturator internus muscle (solid arrows). IL, portion of the ilium; A, acetabulum; P, the entire pelvic floor, including the superior and inferior pubic ramus; SP, superior pubic ramus; IP, inferior pubic ramus and pubis; SY, symphysis pubis. (Courtesy of Martin M. Malawer.) Femoral component: Ream and place the uncemented femoral component through the posterior lateral approach before proceeding with iliac osteotomy resection. Acetabulum: Ream the allograft for the acetabular component and place the acetabular component (cement and screws) into the allograft to confirm graft and acetabular orientation in situ with radiography before screw or cement fixation. Check acetabulum positioning with radiographs before and after fixation or cementation. Orient the iliac graft before confirming the acetabular orientation, and fix the graft with a reconstruction plate and screws. Use an extended polyethylene acetabular rim, and consider a large femoral head (32 to 36 mm) to improve postoperative stability. Closure: Using the inguinal ligaments, reconstruct the abductors, especially if a trochanteric osteotomy was done. Perform pelvic closure at the iliac crest and inguinal canal with wound drainage catheters.

▪ Type II: Resection and Reconstruction with Saddle Prosthesis Notchplasty A notch is created in the remaining ilium using a high-speed burr. The notch should be placed in the thickest region of the remaining bone (usually medial) (TECH FIG 3A-C). Preparation of the Proximal Femur The proximal femur is prepared as for a standard femoral component. The intramedullary canal of the proximal femur is reamed to accept the largest diameter stem and allow for a 2-mm circumferential cement mantle. Once reaming is completed and the appropriately sized stem (diameter and length) is selected, a distal femoral cement plug is inserted to a depth of 2 cm below the tip of the selected femoral stem. The femoral canal then is irrigated with saline and packed with gauze. Once the cement (polymethylmethacrylate) is prepared, the gauze is

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removed, and the femoral prosthesis is cemented within the proximal femur. Trial Reduction A reduction using trial components is critical in assessing accurate length of the base component (intercalary segment) and determining optimum soft tissue tension (TECH FIG 3D-K). The base component length should be determined by the distance between the ilium and femoral neck cuts because the P.210 length indicated on the base component is the total length from the notch of the saddle to the femoral collar. The base component should be selected so that reduction is barely possible and there is minimum “play” in the reduced joint. The surgeon should be able to reattach the abductor mechanism to its anatomic position on the osteotomized greater trochanter. A trial reduction also can determine areas where the saddle component may impinge on the existing notch during intraoperative range of motion. These areas can be further contoured with a high-speed burr to prevent impingement, which may result in limited motion or dislocation. Hip motion (flexion to at least 90 degrees, extension to 30 degrees, abduction to 45 degrees, adduction to neutral, and rotation) should be possible without evidence of impingement or dislocation. Abductor Mechanism Reconstruction The osteotomized greater trochanter and abductors are reattached to their original location using cables. If the greater trochanter was included in the resected specimen, the abductor mechanism is reattached to the prosthesis using 3-mm Dacron tapes or a cable system. Soft tissue tension and prosthetic stability are again tested once the abductor mechanism reconstruction is complete. The piriformis and short external rotator muscles are brought forward and reattached to the proximal femur (or prosthesis). The gluteus maximus muscle is then reattached to its insertion using nonabsorbable suture (TECH FIG 3L-N). Pelvic closure involves attachment of the inguinal canal and abdominal wall to the symphysis pubis and lateral iliac crest. Soft tissue tension and prosthetic stability are tested again once the abductor mechanism reconstruction is complete. The piriformis and short external rotator muscles are brought forward and reattached to the proximal femur (or prosthesis). The gluteus maximus is then reattached to its insertion using nonabsorbable suture. For high type II pelvic resections, reconstruction should be carried out with a partial pelvic prosthesis.

TECH FIG 3 • A. Photograph following a periacetabular resection showing the remaining ilium (IL), the sciatic nerve (S), the greater trochanteric osteotomy (G), and the femoral head. B. Creation of the deep notch (large arrows). C. Reduction of the saddle prosthesis into the iliac notch (IL). The notch (solid arrows) must be as deep as the saddle and permit approximately 45 degrees of flexion and extension as well as abduction and adduction. D. Surgical exposure using the utilitarian pelvic incision. E. A large posterior fasciocutaneous flap based medially permits the release of the gluteus maximus. (continued) P.211

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TECH FIG 3 • (continued) F. Schematic diagram of the mobilization of the periacetabular structures and the three osteotomies that are necessary for a complete resection of the acetabulum. G. Schematic of the “close-up” view of the superior pubic ramus osteotomy. H. The infra-acetabular osteotomy. I. A notch is made in the supra-acetabular roof or remaining ilium for the saddle prosthesis to sit in. J. Saddle prosthesis reduced into the notch. K. Schematic diagram of the saddle prosthesis following a periacetabular resection for sarcoma and radical curettage for a large acetabular metastasis. Postoperative radiographs and CT scans demonstrating common postoperative radiographic findings. (continued) P.212

TECH FIG 3 • (continued) L. Anteroposterior (AP) radiograph of the pelvis with a saddle prosthesis in place. M. A 45-degree oblique radiograph of the affected side of the pelvis. N. CT scan showing a typical saddle prosthesis in good position. G, gluteal muscles; S, sciatic nerve; IC, iliacus muscle; AB, abductor muscles. (A-C,L-N: Courtesy of Martin M. Malawer; D-K: From Malawer M. Reconstruction following resection of primary periacetabular tumors. Semin Arthroplasty 1999;10:171-179.)

▪ Type III Resection: Pelvic Floor/Anterior Obturator Ring A utilitarian pelvic incision with a perineal extension is used (three-incision approach). The patient is positioned with the ipsilateral hip slightly elevated. The ilioinguinal component of the utilitarian pelvic incision with a lateral and perineal (medial) extension is used (see TECH FIG 1G). This

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incision allows exposure and mobilization of the femoral vessels and nerve through a distal-based anterior flap. Perineal extension of the incision is used to expose the ischium, which is resected through the ischiorectal fossa when the resection is performed for a large pubic lesion. Large myocutaneous flaps are raised. The spermatic cord is reflected medially. The inguinal ligament is transected from its pubic insertion and reflected laterally. The neurovascular bundle (ie, the femoral artery, vein, and nerve) is retracted laterally, exposing the origin of the adductor magnus and pectineus muscles, which is transected off the pubis and reflected distally. Using the lateral component of the incision, the origins of the hamstrings, adductors, and gracilis are transected off the ischium and reflected distally (TECH FIG 4). The first malleable retractor is placed behind the symphysis pubis in front of the bladder. The second malleable retractor is placed behind the superior pubic ramus and in front of the inferior pubic ramus, medial or lateral to the ischium, depending on the required oncologic margins (TECH FIG 4C). Osteotomy through the symphysis pubis and pubic rami is performed. It is important to smooth the sharp bony edges, especially those that lie against the bladder. Surgical wounds around the groin are notoriously associated with a high incidence of dehiscence and infection. Meticulous wound closure with adequate drainage is, therefore, mandatory. Continuous suction is required for 3 to 5 days. Perioperative intravenous antibiotics are continued until the drainage tubes are removed. Postoperative mobilization with weight bearing as tolerated is allowed. Rarely, reconstruction of the pelvic floor with Marlex (CR Bard, Cranston, RI) mesh is required.

TECH FIG 4 • A. The ilioinguinal component of the utilitarian pelvic incision with a modified perineal extension are used. (continued) P.213

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TECH FIG 4 • (continued) B. Schematic of the three osteotomies required to remove the pelvic floor. C. Transection of the symphysis pubis, superior pubic ramus, and ischial osteotomy. (Courtesy of Martin M. Malawer.)

▪ Type IV Resection: Hemipelvic Table 1 describes hemipelvic resection along with other techniques. Combined, extended full pelvic dissection from symphysis pubis to SI joint is required. Complete dissection of the sciatic notch, the hip joint, the sciatic nerve, and the femoral vessels is required. Pelvic reconstruction is more challenging because of the need for fixation at the sacrum and symphysis pubis and the difficulty in orienting a pelvic graft. Some surgeons do not recommend reconstruction but accept 3 inches of shortening and the use of a pelvic long-leg brace. A large amount of intraoperative blood loss and hemipelvic graft fixations present significant surgical challenges. P.214

Table 1 Summary of Pelvic Resection and Reconstruction Techniques

Surgical Technique Type II: posterior iliac resection

Position

Incision

Exposure

Lateral with anterior tilt

Ilioinguinal with or without sacral extension

External oblique and abdominal m.

Vessels and Nerves Careful dissection of femoral n. and vessels; iliac, gluteal vessels

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Resection

Reconstruction

Closure

Iliopsoas, osteotomy at iliac crest

Allograft fixation with 4.5-mm plate

Abdominal wall m. to pelvis with nonabsorbable sutures and two deep drains (anterior and posterior)

Type II: lateral acetabular resection

Straight lateral

Ilioinguinal with separate posterior lateral hip incision

External oblique off superficial lateral crest m., expose hip

External iliac a. and v., obturator n., gluteal vessels, sciatic n.

Hip joint, sciatic notch, external rotators, femoral neck osteotomy

Ream allograft for acetabular placement; cement and screw with 4.5mm plate

Attach inguinal canal and abdominal wall to symphysis pubis and lateral iliac crest

Type III: anterior obturator

Supine

Ilioinguinal incision with anterolateral extension

Symphysis pubis to posterior lateral iliac crest

Femoral sheath, lateral femoral cutaneous n., obturator n., a., v.

Between inferior pubic ramus and ischium, depending on tumor location

Soft tissue with Martex/fascia allograft or Gore-Tex if acetabular anterior column intact. If not intact, then bony obturator allograft

Inguinal canal with nonabsorbable sutures and deep drains; prevent inguinal hernia

Hemipelvic

Lateral

Ilioinguinal

Symphysis to lateral crest and external iliac m.

External iliac

Iliac and hip, with or without obturator

Allograft verse saddle prosthesis

Lateral crest and ilioinguinal canal

Gluteal

Prone

Posterior gluteal

Gluteal m.

Sciatic n., gluteal n., v., a.

Deep proximal posterior greater trochanter, if inferior to notch

Retroperitoneal (soft tissue)

Supine

Symphysis to posterolateral ilium

Midline if bowel is involved. Abdominal/external oblique off iliac crest

Iliac and gluteal vessels, ureter, femoral vessels and nerve, sciatic n.

Usually respects iliopsoas musculature

External oblique abdominal wall reattached to pelvic brim

Reattach external oblique to pelvic brim

Inguinal groin

Supine

Pubic tubercle to lateral iliac crest

Inguinal cord, umbilical

Femoral sheath, inferior epigastric vessels

Inguinal canal

Inguinal ligament

PEARLS AND PITFALLS Vascular problems

▪ Always have vascular control of the major vessels proximally and distally, both arterial and venous, especially common, internal, and external iliac vessels.

Intraoperative bleeding

▪ Severe bleeding usually occurs with venous, not arterial, injuries. Suture and ligate all serious bleeders.

Thrombosis

▪ All patients are at risk to develop an arterial venous thrombosis during or after surgery and should be evaluated (pulses) carefully during and for the first 72 hours. Always confirm adequacy of hemostasis and distal flow and pulses before leaving the operating room. If there is any question, perform an intraoperative or postoperative angiogram.

Postoperative bleeding and

▪ If bleeding continues, and coagulation factors rule out disseminated intravascular coagulation, strongly consider taking the patient back to the operating room. Alternatively, perform an angiogram with attempt at embolization of the bleeding vessel. The degree and timing of the bleeding are important in determining the correct

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coagulopathy

course of action. ▪ If massive (>4.0-5.0 L) bleeding occurs during the dissection, pack the wound with local pressure until the patient's blood pressure stabilizes. ▪ Check prothrombin time, partial thromboplastin time, and platelet counts intraoperatively and every 6 hours for 24-48 hours. ▪ Almost all patients need intensive monitoring following surgery.

Hypocalcemia and hypomagnesemia

▪ Calcium (Ca) always is required intraoperatively. Check the Ca level in the operating room and postoperatively. ▪ Magnesium (Mg) loss is very common following a major bleed, especially in patients treated with induction chemotherapy. The agent that most commonly causes Mg loss is cisplatinum. Patients receiving this form of chemotherapy routinely require a large amount of Mg postoperatively. If left uncorrected, cardiac arrest may occur.

Nerve injuries

▪ Iatrogenic injury may occur to femoral, sciatic, or sacral nerve roots. Injury occurs during dissection (neurapraxia) or sacral screw fixation. Obturator nerve sacrifice is not a significant functional loss.

Ureter and bladder injuries

▪ Consider a preoperative ureteral stent for all large tumors. Foley catheter placement enables palpation of the bladder intraoperatively. ▪ Repair bladder wall injuries in two or three layers. Check carefully for bladder injury if hematuria or oliguria occurs intraoperatively.

Hip

▪ Check hip radiographically for stability prior to and after wound closure.

General

▪ Remember that the first step in avoiding injury to the critical structures mentioned is taking the time to identify and tag all of them initially during dissection.

P.215

POSTOPERATIVE CARE The distal extremity pulses are checked immediately after surgery and every hour for the first 24 hours. Late arterial thrombosis often is due to intimal injuries. Persistent wound drainage usually is due to a large retroperitoneal collection. If the wound continues to drain after 4 to 7 days postoperatively, wound irrigation and drainage in the operating room should be considered. All postoperative patients should have a pelvic radiograph once a week for the first 2 weeks. After initial postoperative stabilization, postoperative complete blood cell count and laboratory studies daily should be checked for the first week then twice per week. Postoperative mobilization is highly individualized: In type I resection, abdominal wall to abductors are maintained in abduction for 7 days in bed and then in a pelvic-thigh brace that avoids excessive adduction. Type II resection and reconstruction is very variable. Patients with a saddle prosthesis and composite allograft are maintained on partial weight bearing for 3 to 6 months and need a pelvic and thigh brace for 2 to 3 months. Patients with a type III resection with or without Marlex reconstruction are kept in bed with the lower extremity in neutral (it is necessary to avoid abduction) to avoid a perineal incision dehiscence. A pelvic and thigh orthosis is used for about 3 months. Full weight bearing can be initiated early if the medial wall of the acetabulum was not involved.

COMPLICATIONS Early Bleeding: Most problems with intraoperative bleeding occur with venous, not arterial, bleeding. Coagulopathy and the need for large blood transfusions are common complications. Coagulation factors, Ca, and Mg should be monitored. Patients should receive packed cells, fresh frozen plasma, platelets, Ca, and Mg as necessary during and after surgery. Patients with (>500 mL per hour per 3 hours) blood loss in the immediate postoperative interval should be considered for postoperative embolization to control blood loss. Arterial thrombosis occurs due to intimal flap tear and should be monitored by distal pulse measurement with Doppler, every hour for the first 24 hours. If arterial thrombosis occurs, immediate thrombectomy is required. Nerve: Postoperative femoral or sciatic neurapraxia are common and should be observed. Ureter/bladder: Patients should be evaluated for intraoperative hematuria or oliguria, which may suggest bladder or ureter injury. Urine output is routinely measured hourly during surgery. The Foley urinary catheter is kept in place for 4 to 7 days. Urethral injuries are diagnosed postoperatively by retrograde cystogram and require surgical treatment. Bowel injuries require repair or resection and possible colostomy. Major ileus is a common problem following extensive pelvic surgery. The postoperative patient should have nothing by mouth until bowel injury recovers (with a nasogastric tube in place) until appropriate bowel sounds return (usually 3 to 4 days).

Late Complications Infection: Deep infection develops in 20% to 30% of patients following pelvic surgery. If such an infection occurs, the patient must be taken back to the operating room, and removal of the prosthesis and allograft must be considered. Dislocation: The dislocation rate for a saddle prosthesis is 5% to 10%. This rate may be even higher for “composite” reconstructions. Failure of the allograft may take the form of fracture through the allograft or failure of fixation. P.216 Prosthesis failure includes failure of the reconstruction ring, acetabular cap, screws, and plate.

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Morbidity and mortality after pelvic resection remains high. Hemipelvectomy may be required due to local recurrence, infection, or uncontrolled bleeding.

SUGGESTED READINGS 1. Aboulafia AJ, Buch R, Mathews J, et al. Reconstruction using the saddle prosthesis following excision of primary and metastatic periacetabular tumors. Clin Orthop Relat Res 1995;(314):203-213. 2. Aljassir F, Beadel GP, Turcotte RE, et al. Outcome after pelvic sarcoma resection reconstructed with saddle prosthesis. Clin Orthop Relat Res 2005;438:36-41. 3. Cottias P, Jeanrot C, Vinh TS, et al. Complications and functional evaluation of 17 saddle prostheses for resection of periacetabular tumors. J Surg Oncol 2001;78:90-100. 4. Enneking WF, Dunham WK. Resection and reconstruction for primary neoplasms involving the innominate bone. J Bone Joint Surg Am 1978;60:731-746. 5. Hillmann A, Hoffmann C, Gosheger G, et al. Tumors of the pelvis: complications after reconstruction. Arch Orthop Trauma Surg 2003;123:340344. 6. Ozaki T, Hoffmann C, Hillmann A, et al. Implantation of hemipelvic prosthesis after resection of sarcoma. Clin Orthop Relat Res 2002; (396):197-205. 7. Renard AJ, Veth RP, Schreuder HW, et al. The saddle prosthesis in pelvic primary and secondary musculoskeletal tumors: functional results at several postoperative intervals. Arch Orthop Trauma Surg 2000;120:188-194. 8. Shin KH, Rougraff BT, Simon MA. Oncologic outcomes of primary bone sarcomas of the pelvis. Clin Orthop Relat Res 1994;(304):207-217. 9. Wirbel RJ, Schulte M, Mutschler WE. Surgical treatment of pelvic sarcomas: oncologic and functional outcome. Clin Orthop Relat Res 2001; (390):190-205.

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Chapter 19 Buttockectomy James C. Wittig Martin M. Malawer

BACKGROUND The gluteus maximus (buttock) is a common site for highand low-grade soft tissue sarcomas. The gluteus maximus is a “quiet area” for soft tissue sarcomas and rarely become symptomatic until they are extremely large. Traditionally, low- and high-grade soft tissue sarcomas of the buttock were treated with a posterior cutaneous flap hemipelvectomy. Advances in limb-sparing surgical procedures have permitted resections with safe margins in most sarcomas and have reduced the need for hemipelvectomy for tumors in this region. Tumors of the gluteus maximus are often confined to this muscle and do not extend to the underlying retrogluteal space or involve the sacrum or femur. The most significant structure in the retrogluteal space that must be evaluated is the sciatic nerve. Minimal reconstruction is required. During the postoperative period, it is important to take measures to prevent the formation of large postoperative seromas. The functional outcome of a resection of the gluteus maximus is a minimal deficit in hip extension only. The gait is normal. A hemipelvectomy rarely is required for a soft tissue sarcoma of the buttock unless it is extremely large or accompanied by fungation, infection, or extension into the ischiorectal space, pelvis, and hip. Direct sacral or iliac bone involvement, which is rare, often necessitates an amputation. About 90% of soft tissue sarcomas arising in the buttock can be resected and treated adequately by a limbsparing surgery. Low-grade soft tissue sarcomas of the gluteus maximus usually require surgery only; highgrade soft tissue sarcomas in this region, like those in other anatomic areas, are also usually treated with chemotherapy and/or radiation preoperatively and/or postoperatively. A small group of selected patients with high-grade sarcomas in the buttock area received induction chemotherapy. The field is treated with postoperative radiation if it is required. The major indications for an amputation are extremely large sarcomas that involve the adjacent bone, the sciatic nerve, or the ischiorectal fossa.

ANATOMY The gluteus maximus arises from the sacral lamina, iliac crest, and ischium. It passes obliquely to its insertion onto the proximal portion of the iliotibial band. This insertion begins above the greater trochanter, passes 4 to 5 cm below the greater trochanter, and then attaches to the adjacent femur. The area underneath the gluteus maximus is termed the retrogluteal space. This area consists of the posterior hip musculature, including the external rotators and portions of the gluteus medius muscle. The sciatic nerve lies in the retrogluteal space. The gluteus maximus does not attach to the retrogluteal structures as it passes over them. This permits easier surgical dissection of the retrogluteal plane and preservation of the sciatic nerve in many situations. http://e-surg.com

As it passes from the sacrum to the femur, the gluteus maximus covers the sacroiliac joint and the sacrospinous and sacrotuberous ligaments as well as a portion of the ischiorectal fossa. Most importantly, the sciatic nerve exits the pelvis through the sciatic notch (FIG 1) and passes inferiorly to the piriformis muscle. This nerve is identified in the halfway distance between the ischial tuberosity and greater trochanter and lies in close proximity to the posterior fascia of the gluteus maximus; therefore, large tumors of the gluteus maximus may involve the sciatic nerve. The sciatic nerve, however, rarely is involved by the tumor; most often, it is displaced around the capsule or pseudocapsule. The inferior gluteal vessels pass below the piriformis muscle to enter the midportion of the gluteus maximus. The inferior gluteal vessels are routinely ligated.

INDICATIONS A gluteus maximus resection is indicated for patients with lowand high-grade sarcomas confined to the gluteus maximus.

CONTRAINDICATIONS Large tumors that involve the true pelvis or ischiorectal space Involvement of the sacrum or ilium Sciatic nerve involvement (although, on occasion, the sciatic nerve may be resected) Pelvic extension through the sciatic notch

IMAGING STUDIES Computed Tomography and Magnetic Resonance Imaging Computed tomography (CT) and magnetic resonance imaging (MRI) are most useful in determining the extent of tumor involvement of the gluteus maximus Close evaluation determines the involvement of the adjacent sacrum, femur, and sciatic nerve. Attention should be placed on the evaluation of the structures of the retrogluteal space, including the hip joint and sciatic nerve, and ischiorectal fossa. Buttock tumors may extend into the pelvis through the sciatic notch (FIG 2). P.218

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FIG 1 • Large sarcoma of the buttock extending through sciatic notch and compressing sciatic nerve. The sciatic nerve originates in the lower spine, threads into the iliac portion of the pelvis, exits through the sciatic notch, and passes inferiorly to the piriformis muscle. Underneath the gluteus maximus, the sciatic nerve lies posterior to the superior gemellus muscle, obturator internus muscle, the inferior gemellus muscle, and the quadratus femoris. On this coronal T1 image, the tumor involves the gluteus maximus. Buttock tumors grow along the path of least resistance and can extend through the sciatic notch and into the pelvis. It can also extend distally into the thigh and invade the iliac wing. One cannot completely determine the extent of involvement of the sciatic nerve by the tumor. The sciatic nerve, however, is rarely involved by the actual tumor and is usually compressed and displaced by the capsule or pseudocapsule of the tumor.

Bone and Positron Emission Tomography Scans Tumor involvement may extend to the crest of the ilium, the sacrum, and the proximal femur. These areas should be evaluated by bone scintigraphy. Positron emission tomography (PET) scan is useful in determining the anatomic soft tissue extension of buttock tumors (FIG 3). http://e-surg.com

Angiography Angiography is not routinely performed when evaluating tumors of the gluteus maximus. It may be useful in preoperative embolization or preoperative intra-arterial chemotherapy.

Biopsy The biopsy site must be in line with the incision for a hemipelvectomy should one be required. Surgeons performing a biopsy of tumors of the buttock must, therefore, be familiar with the surgical incisions for both posterior flap and anterior flap hemipelvectomies (see Chaps. 21 and 22).

FIG 2 • Fluid-fluid levels of high-grade buttock sarcoma. Tumors that are greater than 5 cm in any dimension or located deep to the deep fascia can usually be categorized as soft tissue sarcomas. On this T2 axial fatsuppressed image, this high-grade buttock sarcoma demonstrates a heterogeneous mass with significant hemorrhage and necrosis. The degradation of hemorrhagic products can produce fluid-fluid levels on an MRI. The tumor and gluteus maximus are noted. This tumor is confined to the gluteus maximus. The tumor does not involve the ischiorectal fossa or the hip joint and does not extend into the pelvis via the sciatic notch. The anterior flap hemipelvectomy, as described by Sugarbaker et al,1 is preferred for large sarcomas of the buttock area. In this procedure, the entire musculature and skin are removed with the amputation, and the anterior myocutaneous flap, consisting of the quadriceps muscle, is used to close the defect. If a posterior flap is used, care must be taken not to contaminate the posterior skin or fascia. The biopsy site must, therefore, be along the lateral aspects of a posterior incision and must avoid the greater trochanter, sciatic nerve, ischiorectal fossa, and greater trochanter. http://e-surg.com

FIG 3 • A coronal PET CT shows the extent of tumor growth in the right gluteus maximus via observation of radioactive glucose uptake. Images demonstrate hypermetabolism within the tumor. The tumor and bladder are noted. The soft tissue is unremarkable outside of the tissue. P.219

TECHNIQUES ▪ Exposure A large curvilinear incision is made beginning at the posterior aspect of the crest of the ilium, curving distally following the gluteus maximus muscle along the iliotibial band (TECH FIG 1A,B), passing over the greater trochanter to about 6 cm distal, and then curving posteriorly back toward the inner aspect of the thigh along the gluteal fold. This incision makes it possible to elevate a large posterior flap. To determine resectability or operability, the sciatic nerve is identified distal to the resection site. It can be identified between the medial and lateral hamstring muscles or just lateral to the ischium before it passes underneath the gluteus maximus muscle. The nerve is palpated below the gluteus maximus muscle toward the piriformis muscle (TECH FIG 1C,D).

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TECH FIG 1 • A. A lateral position is used. The affected extremity is prepped free from the abdominal wall to the foot. The incision extends along the iliac crest and encompasses the biopsy site by 2 to 3 cm and then extends along the greater trochanter and along the gluteus maximus skin fold. The incision permits wide excision of the underlying gluteus maximus muscle and early exploration and preservation of the sciatic nerve. If the tumor is unresectable, an anterior flap hemipelvectomy is required. B. A fasciocutaneous flap is elevated and dissected with the electrocautery toward the origin of the gluteus maximus muscle (from the sacrum). This permits exposure of the entire gluteus maximus muscle. The biopsy site is left en bloc with the gluteus maximus muscle. If the tumor is extremely large, only a subcutaneous flap is used, with the deep fascia remaining on the tumor side. (continued) P.220

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TECH FIG 1 • (continued) C. The retrogluteal space, consisting of the hip rotators, abductor muscles, and the sciatic nerve, is seen in this illustration. The gluteus maximus is mobilized from inferior along the deep posterior thigh fascia and released from the iliotibial band up to the iliac crest. It is then dissected to its origin along the sacral alar and the sacrospinous and sacrotuberous ligaments. The sciatic nerve is explored initially by the surgeon placing his or her hand under the gluteus maximus to ensure that the nerve is free from the tumor. D. The sciatic nerve is identified distal to the tumor in normal tissue and mobilized away from the pseudocapsule of the tumor. The sciatic nerve can be identified distally between the medial and lateral hamstrings or lateral to the ischium before it passes under the gluteus maximus muscle. It is separated from the tumor up to the piriformis muscle. The piriformis muscle is detached from its insertion and the sciatic nerve is then followed through the sciatic notch into the pelvis. When the sciatic nerve is completely protected, the gluteus maximus is detached from the sacrotuberous and sacrospinous ligaments as well as from the sacrum and posterior ileum. The iliotibial band is detached from its insertion on the femur. Once the gluteus maximus is detached from all of its origins and insertions, it can be removed with the tumor accompanying a compartmental resection. (Courtesy of Martin M. Malawer.)

▪ Preservation of the Sciatic Nerve and Resection

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The gluteus maximus is detached from the iliotibial band throughout its length and from the femur distally. This muscle is then flapped medially to expose the inferior gluteal vessels and nerve, which are then ligated. The sciatic nerve is displaced anteriorly to protect it during the dissection (TECH FIG 2A-C). Removal of the gluteus maximus involves detaching this muscle from the sacrotuberous and sacrospinous ligaments as well as the lamina and sacral alar (TECH FIG 2D,E). P.221

TECH FIG 2 • A,B. Preservation of the sciatic nerve. Intraoperative surgical images demonstrate the preservation of the sciatic nerve. One of the essential keys to performing limb-sparing surgery for a buttock sarcoma is preservation of the sciatic nerve. The sciatic nerve is compressed by the pseudocapsule of the tumor up to the sciatic notch. After the gluteus maximus is detached from the femur and iliotibial band, the muscle is flapped medially which leads to the exposure and ligation of the inferior gluteal vessels and nerve. The sciatic nerve is displaced anteriorly to protect during dissection and resection. C. Intraoperative image of tumor/gluteus maximus en bloc resection. The gluteus maximus is reflected posteriorly and the inferior http://e-surg.com

gluteal vessels and nerves are ligated. The mass is removed via radical resection. D. The final surgical maneuver to release the gluteus maximus from the surgical bed is the transection through the origin of its muscle from the sacrospinous and sacrotuberous ligaments. Care should be taken not to enter the ischiorectal space. The ischium should be palpated and a hand placed above the ischium and below the gluteus maximus for release of the tumor specimen. E. Gross pathology of the gluteus maximus tumor exhibits wide surgical resection. The entire tumor is covered with soft tissue and the muscle is removed from origin to insertion. Although the tumor is confined to the gluteus maximus, en bloc resection involves origins and insertion from the sacrum, femur, ilium, sciatic notch, ischium, and iliotibial tract. Any sciatic notch intervention requires careful manipulation because the sciatic nerve exits through the sciatic notch. The sciatic notch may need to be enlarged with a saw for tumors extending significantly through the notch. Sciatic nerve damage can lead to buttock pain radiating down to the foot, weakness, tingling, and numbness in the leg. (Courtesy of Martin M. Malawer.) P.222

▪ Completion To prevent a large postoperative seroma, the large posterior fasciocutaneous flap must be tacked down to the remaining underlying muscle very carefully. Multiple large drains are used (TECH FIG 3). The patient remains supine for 72 hours to prevent the development of a seroma.

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TECH FIG 3 • The large posterior fasciocutaneous flap is closed, and large suction drainage tubes are placed. The flap is tacked down to the underlying hip rotator muscles and abductor muscles to avoid a postoperative seroma. A pressure dressing is used for 48 to 72 hours, and the patient lies flat postoperatively. (Courtesy of Martin M. Malawer.)

POSTOPERATIVE CARE Postoperative radiation therapy could be required for highgrade tumors once the flaps are well healed (4 to 6 weeks after surgery). Postoperative chemotherapy could be considered following radiation therapy for patients with high-grade tumors.

OUTCOMES The only deficit following gluteus maximus resection is weakness with hip extension. Secondary hip extensors enable some hip extension, and the patient's gait is virtually normal. If the sciatic nerve requires resection, there is loss of foot and ankle control, so that the patient requires an ankle-foot orthosis. Depending on the level of the sciatic nerve resection, the first branch to the biceps femoris may be intact. If that is the case, good knee flexion will be retained. Knee flexion also depends on the sartorius muscle (innervated by the femoral nerve), the gracilis muscle (innervated by the obturator nerve), and the two heads of the gastrocnemius muscle that insert across the knee joint.

COMPLICATIONS The most common postoperative complication is the development of a large seroma because there is a large dead space with only a subcutaneous flap on top. We have used the quadratus femoris muscle rotated over the sciatic nerve for soft tissue coverage of the nerve. Similarly, the piriformis is rotated distally. The flap is carefully tacked down throughout its course in its midportion to eliminate “dead” space. One 20-gauge chest tube and two Jackson-Pratt drains are used, and the remaining portion of the flap is closed. A compressive dressing is used for 72 hours. In the case of recurrent sarcomas of the buttocks, tumor fungation, massive contamination, or extensive tumor involvement of the adjacent structures, an anterior flap hemipelvectomy is recommended (see Chap. 22 for a discussion of this procedure).

REFERENCE 1. Sugarbaker PH, Chretien PA. Hemipelvectomy for buttock tumors utilizing an anterior myocutaneous flap of quadriceps femoris muscle. Ann Surg 1983;197:106-115.

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Chapter 20 Surgical Management of Metastatic Bone Disease: Pelvic Lesions Jacob Bickels Martin M. Malawer

BACKGROUND Metastatic tumors of the pelvis may cause pain and a major loss of function and weight-bearing capacity. Because of the relatively large size of the pelvic cavity and the elastic nature of the organs it contains and its surrounding muscles, tumors at that site usually reach considerable size before causing symptoms. Although some locations of these metastases within the pelvis have no impact on pelvic stability and function (eg, ilium, pubis), tumors of the posterior ilium may pose a threat to lumbosacral integrity, and tumors of the acetabulum may profoundly impair hip function and the weightbearing capacity of the lower extremity. Both primary sarcomas and metastatic tumors usually present with considerable extension into the soft tissues. Because of their inherent sensitivity to radiation therapy, however, the surgical management of metastatic lesions does not require en bloc resection of overlying muscles, and microscopic residua are treated with adjuvant radiation. The complex anatomy of the pelvic girdle mandates detailed preoperative imaging, planning of exposure and reconstruction technique, and careful and meticulous execution of the surgical procedure.

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FIG 1 • Metastatic tumors of the ilium, periacetabular region, pubis, and posterior ilium require types I, II, III, and IV pelvic resections, respectively. Pelvic metastases are treated with either curettage and reconstruction with cemented hardware or by wide resections. These procedures are grouped together and termed pelvic resections, the classification of which is attributed to Enneking and is based on the resected region of the innominate bone: Type I—ilium Type II—periacetabular region Type III—pubis En bloc resection of the posterior ilium with the sacral ala is classified as an extended type I or type IV resection (FIG 1).1

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Ilium The iliac crest is the attachment site for abdominal wall musculature and quadratus lumborum (FIG 2). The iliacus muscle overlies the inner iliac table and the femoral nerve lies medial to it in the groove between the iliacus and the psoas muscle. Gluteal muscles overlie the outer iliac table.

FIG 2 • Muscle attachments and relevant structures around the innominate bone. P.224

Acetabulum The upper medial mechanical support of the hip joint No muscle attachments http://e-surg.com

Pubis Origin of hip adductors from its inferior aspect The neurovascular bundle runs along the anterior aspect of the pubis. The urinary bladder attaches to its posterior wall.

INDICATIONS Pathologic fracture of the acetabulum Impending pathologic fractures of the acetabulum, which are defined as lesions that extend to the acetabular roof and are associated with cortical destruction and considerable pain on weight bearing Intractable pain associated with locally progressive disease that had shown inadequate response to narcotics and preoperative radiation therapy Solitary bone metastasis in selected patients

IMAGING AND OTHER STAGING STUDIES Plain radiographs and computed tomography of the pelvis and hip joints are mandatory to evaluate the full extent of bone destruction, soft tissue extension, and integrity of the hip joint. Magnetic resonance imaging rarely adds additional information: It is indicated in lesions which have diffused intramedullary extension that is commonly underestimated by computed tomography, such as multiple myeloma. Total body bone scintigraphy is done for detecting synchronous metastases elsewhere in the skeleton. At the conclusion of imaging, the surgeon should be able to answer the following questions: What is the full extent of bone destruction and soft tissue extension that are related to the tumor? Is the lesion an impending fracture? If not, it should probably be treated nonsurgically. What incision should be used to obtain optimal exposure (FIG 3)? What would be the best technique for resection and reconstruction, if required? Are there additional skeletal metastases and, if so, can they be managed by nonoperative techniques or do they require surgery?

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FIG 3 • Plain radiographs and computed tomographies with coronal reconstruction showing acetabular metastases with their most pronounced cortical destruction at the lateral acetabular wall (A-C) and medial acetabular wall (D-F). The former lesion is exposed after reflection of the glutei from the outer iliac table and the latter after reflection of the iliacus from the inner iliac table. P.225

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FIG 3 • (continued) Hypervascular lesions (eg, metastatic renal cell or thyroid carcinomas) can bleed profusely and cause a lifethreatening blood loss within a few minutes upon tumor exposure and curettage. Preoperative embolization of these tumors is strongly advised to reduce intraoperative blood loss.4,5

SURGICAL MANAGEMENT Positioning Types I, II, and III resection: The patient is placed supine on the operating table with a slight elevation of the ipsilateral hip. Type IV resection: The patient is placed in a true lateral position with the affected side of the pelvic girdle uppermost. The operating table is bent with the breakage point just below the contralateral hip: Such a position widens the space between the iliac crest and the lower aspect of the chest wall, allowing a comfortable approach and easier maneuvering at that site (FIG 4).

Approach The most useful approach to pelvic resections is the utilitarian pelvic incision. All or part of the incision can be http://e-surg.com

used for adequate exploration and resection of pelvic girdle metastases. The incision begins at the posterior inferior iliac spine and extends along the iliac crest to the anterior superior iliac spine. It is then separated into two arms: One extends along the inguinal ligament up to the symphysis pubis, and the other turns distally over the anterior thigh for one-third the length of the thigh and then curves laterally just posterior to the shaft of the femur below the greater trochanter and follows the insertion of the gluteus maximus muscle. Reflection of the posterior gluteus maximus flap exposes the proximal third of the femur, the sciatic notch, the sacrotuberous and sacrospinous ligaments, the origin of the hamstrings from the ischium, the lateral margin of the sacrum, and the entire buttock (FIG 5A). Posteriorly, the incision extends along the posterior iliac crest, posterior superior iliac spine, and ipsilateral hemisacrum (FIG 5B). P.226

FIG 4 • A. Metastatic carcinoma of the posterior ilium. B,C. The patient is placed in a true lateral position and the operating table is broken at the hip level to allow easier access to the flank.

FIG 5 • A. The utilitarian pelvic incision. B. The posterior component of the incision, used for exposure and resection of tumors of the posterior ilium and sacrum. http://e-surg.com

P.227

TECHNIQUES ▪ Exposure Type I Resection The middle component of the utilitarian incision is used to expose the iliac crest. Using electrocautery, the glutei are detached and reflected from the outer iliac table. The iliacus muscle is similarly detached and reflected from the inner table (TECH FIG 1). Type II Resection Lesions with lateral cortical destruction The middle component of the utilitarian incision up to the anterior superior iliac spine with a 5-cm extension along the lateral thigh arm of the incision is used for these lesions.

TECH FIG 1 • A,B. Metastatic sarcoma of the ilium. C. The tumor is exposed after detachment and http://e-surg.com

reflection of the glutei and iliacus from the outer and inner iliac tables, respectively. D. Intraoperative photograph showing the exposed ilium after reflection of the glutei and iliacus muscles. Electrocautery is applied to detach and reflect the glutei from the outer iliac table, exposing the lateral wall of the acetabulum (TECH FIG 2). Lesions with medial cortical destruction The middle component of the utilitarian incision up to the anterior superior iliac spine with a 5-cm extension along the inguinal arm of the incision is used for these lesions. Electrocautery is applied to detach and deflect the iliacus from the inner iliac table, exposing the medial wall of the acetabulum (TECH FIG 3). P.228

TECH FIG 2 • A. Exposure of an acetabular metastasis that has a lateral cortical destruction is accomplished by using the middle component of the utilitarian incision up to the anterior superior iliac spine with a 5-cm extension along the lateral thigh arm of the incision. B,C. Using electrocautery, the glutei are detached and reflected from the outer iliac table, exposing the lateral wall of the acetabulum. http://e-surg.com

Lesions that have similar extent of lateral and medial cortical destruction are preferably approached from their lateral aspect because performance of the surgery is technically easier from that side. Type III Resection The inguinal component of the utilitarian incision, from the anterior superior iliac spine to 2 cm across the symphysis pubis, is used for this resection. The neurovascular bundle is isolated, marked with vessel loops, and mobilized. The retropubic space is exposed, and a pad is inserted between the urinary bladder and the pubis. Muscle attachments are then detached from the inferior aspect of the pubis (TECH FIG 4). Type IV Resection The posterior component of the utilitarian incision is used for this resection. Electrocautery is applied to detach the glutei from their origin at the posterior iliac crest and to reflect them (TECH FIG 5). P.229

TECH FIG 3 • A. Exposure of an acetabular metastasis that has a medial cortical destruction is achieved by using the middle component of the utilitarian incision up to the anterior superior iliac spine with a 5-cm extension along the inguinal arm of the incision. B,C. Using electrocautery, the iliacus is detached and reflected from the inner iliac table, exposing the medial wall of the acetabulum.

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TECH FIG 4 • A. Exposure of a pubic metastasis is accomplished by using the inguinal component of the utilitarian incision from the anterior superior iliac spine to 2 cm across the symphysis pubis. B. The affected bone is reached after isolation and mobilization of the neurovascular bundle from the anterior aspect of the pubis, reflection of the urinary bladder from its posterior aspect, and detachment and reflection of the adductors origin from its inferior aspect. P.230

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TECH FIG 5 • A,B. Exposure of a metastasis at the posterior ilium is achieved by using the posterior component of the utilitarian incision. C. The glutei are detached from their origin from the posterior iliac crest and outer table. D. Reflection exposes the outer iliac table.

▪ Tumor Removal Type I Resection This resection involves an osteotomy of the ilium around the lesion, and 1- to 2-cm margins are sufficient for resection of metastases at that site (TECH FIG 6). Tumor curettage is neither feasible nor justified at that site because a resection of the ilium that does not impair acetabular or sacroiliac joint integrity rarely has an impact on function. Type II Resection Curettage A wide cortical window is made above the lesion (TECH FIG 7A). Gross tumor is removed with hand curettes (TECH FIG 7B,C). Curettage should be meticulous and leave only microscopic disease in the tumor cavity. It is followed by high-speed burr drilling of the tumor cavity walls (TECH FIG 7D,E).

TECH FIG 6 • Plain radiograph showing the ilium following a type I resection. The sacroiliac joint and the acetabulum are intact and function is, therefore, expected to remain intact. P.231

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TECH FIG 7 • A. A wide cortical window is created. B,C. Gross tumor is meticulously removed with hand curettes, leaving only microscopic disease. D,E. Curettage is followed by high-speed burr drilling of the tumor cavity. P.232 Resection When the entire acetabulum is destroyed and no cortices are left to contain an internal fixation device and cement, a formal resection is done in the same manner as for primary sarcomas of bone (see the chapter on pelvic resection). The incision is extended along the upper thigh, the joint capsule is opened, the femur is dislocated, and an acetabular osteotomy and resection are carried out. Type III Resection Curettage A longitudinal cortical window with oval edges is made above the lesion, and tumor curettage and highhttp://e-surg.com

speed burr drilling are done in the same manner as in a type II resection (TECH FIG 8). Resection When the pubis is destroyed and no cortices are left to allow curettage and burr-drilling, the incision is extended to exposed intact cortices from both sides of the lesion, followed by formal resection of the pubic segment.

TECH FIG 8 • A. Plain radiograph showing metastatic carcinoma of the superior pubic ramus. B. Curettage of the tumor cavity. The femoral vessels and nerve are marked with red and yellow vessel loops, respectively. C. Curettage is followed by high-speed burr drilling. Type IV Resection Curettage A longitudinal cortical window with oval edges is made above the lesion, and tumor curettage and highspeed burr drilling are done in the same manner as in a type II resection (TECH FIG 9). Resection When the posterior ilium is destroyed and no cortices are left to allow curettage and burr-drilling, wide resection of the posterior iliac segment is carried out. These resections commonly require the en bloc removal of the adjacent component of the sacroiliac joint and potentially can impair stability of the posterior pelvic girdle. http://e-surg.com

P.233

TECH FIG 9 • A. Plain radiograph, (B) computed tomography, and (C) magnetic resonance imaging showing metastatic carcinoma of the right posterior ilium. D. Gross tumor at the posterior ilium is meticulously removed with hand curettes, leaving only microscopic disease. E. Curettage is followed by high-speed burr drilling of the tumor cavity.

▪ Mechanical Reconstruction Type I Resection Type I resections require no reconstruction. Type II Resection Curettage After completion of tumor removal with burr-drilling, the tumor cavity is reconstructed with cemented Steinmann pins, which are introduced through the iliac crest. Following placement of the pins tips against the subchondral bone, the tumor cavity is filled with cement (TECH FIG 10). Acetabular metastases may destroy the subchondral bone and dissociate the articular cartilage. In such cases, reconstruction of the articulating surface of the acetabulum can be done with a prosthetic http://e-surg.com

polyethylene insert that had been shaped with a high-speed burr to match the convexity of the femoral head (TECH FIG 11). Resection Reconstruction following resection of the acetabulum may include a saddle prosthesis or leaving a flail extremity with no reconstruction. Type III Resection Following curettage, the tumor cavity is filled with cement, which does not contribute to pelvic stability but allows easier determination of tumor extent on the postoperative imaging studies and subsequent planning of radiation fields as well as early detection of local tumor recurrence at the cement-bone interface. No reconstruction is required if resection of a pubic segment had been performed. Type IV Resection Curettage Following curettage, the tumor cavity is filled with cement, the purpose of which is similar to cementation of a pubic defect. P.234

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TECH FIG 10 • A,B. Steinmann pins are introduced through the iliac crest into the tumor cavity up to the subchondral bone. After placement of the pins, the tumor cavity is filled with bone cement. C. Plain radiograph showing the acetabular cavity reconstructed with cemented Steinmann pins. Resection Small defects of the sacroiliac joints do not require reinforcement. Medium-sized defects, however, require such reinforcement with a plate to prevent dissociation of the joint. Complete resection of the sacroiliac joint compromises stability of the posterior pelvic girdle. Gradual upward migration of the ilium on weight bearing and limb length discrepancy will most likely occur (TECH FIG 12). Traction of the lower extremity followed by a protected weightbearing protocol is implemented in order to reduce the extent of limb shortening. P.235

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TECH FIG 11 • Deficient articular cartilage may be reconstructed with a polyethylene insert.

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TECH FIG 12 • A. Small defects of the sacroiliac joint following a type IV pelvic resection does not compromise pelvic girdle stability and, therefore, does not require reconstruction. Medium-sized defects require reinforcement (B), and complete resection of the sacroiliac joint requires skin traction and protected weight bearing (C). This protocol is intended to allow scarring of the surgical field with the operated extremity pulled to its full extent, which may prevent upward migration of the lower extremity and limb length discrepancy. P.236

▪ Soft Tissue Reconstruction and Wound Closure The glutei and iliacus are sutured over the innominate bone and both are sutured to the abdominal wall musculature (TECH FIG 13). It is important to properly attach these three muscle groups to restore muscle origin attachment and abdominal wall continuity, thereby allowing function of the glutei and iliacus and preventing herniation of the pelvic viscera to the flank, respectively.

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TECH FIG 13 • Plain radiograph (A) and computed tomography (B) showing metastatic carcinoma of the left ilium. C. The iliac stump that remains after osteotomy (the femoral nerve is lifted with a vessel loop and a clamp is passed through the sciatic notch). D. The glutei are sutured to the iliacus muscle to cover the iliac stump and both are sutured to the abdominal wall musculature to avoid herniation of the pelvic viscera into the flank. The surgical wound is closed over suction drains, and an abduction pillow is used to enable wound healing with minimal stress at the muscle suture line. In the case of a complete resection of the sacroiliac joint and loss of posterior pelvic continuity, skin traction is used to pull the extremity and avoid limb shortening.

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PEARLS AND PITFALLS http://e-surg.com

Indications

▪ Detailed preoperative imaging and anatomic tumor classification ▪ Choice of resection type and extent (curettage vs. resection) and technique of reconstruction, if required

Special considerations

▪ Preoperative embolization of hypervascular lesions

Resection and reconstruction

▪ Tumor removal by curettage and high-speed burr drilling; resection when curettage is not feasible ▪ Reconstruction with cemented hardware ▪ Functional reconstruction of muscle groups

Adjuvant treatment and rehabilitation

▪ Early ambulation with unrestricted weight bearing with the only exception being patients who had complete resection of their sacroiliac joint ▪ Postoperative radiation therapy

POSTOPERATIVE CARE AND REHABILITATION Continuous suction is required for 3 to 5 days, and perioperative intravenous antibiotics are continued until the drainage tubes are removed. Rehabilitation should include early ambulation with unrestricted weight bearing as well as passive and active range of motion of the hip joint. In the case of a complete resection of the sacroiliac joint, skin traction is applied for the first 10 postoperative days, and weight bearing is allowed only after 3 weeks postsurgically have passed: This protocol allows the formation of scar tissue around the sacroiliac defect, which may decrease the extent of iliac migration. Upon wound healing, usually 3 to 4 weeks after surgery, the patients are referred to adjuvant radiation therapy.

OUTCOMES Most patients who undergo resection of pelvic metastases experience a substantial relief of pain and are able to ambulate with full weight bearing. Most of them do not, however, reach their full functional capability because of a relatively slow recovery and muscle weakness due to their progressing oncologic disease and general wasting. Hardware failures are rarely seen if internal fixation devices had been chosen correctly, used properly, and reinforced with cement. Local recurrence rates are less than 10% if there has been adequate tumor removal and if postoperative radiation had been administered.2,3

COMPLICATIONS Deep infection Wound dehiscence due to poor nutritional and catabolic states Deep vein thrombosis Sacroiliac dissociation and upward migration and shortening of lower extremity on weight bearing Herniation of pelvic viscera to the flank Local tumor recurrence

REFERENCES

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1. Enneking WF. The anatomic considerations in tumor surgery: pelvis. In: Enneking WF, ed. Musculoskeletal Tumor Surgery, vol 2. New York: Churchill Livingstone, 1983:483-529. 2. Harrington KD. Impending pathologic fractures from metastatic malignancy: evaluation and management. Instr Course Lect 1986;35:357-381. 3. Harrington KD, Sim FH, Enis JE, et al. Methylmethacrylate as an adjunct in internal fixation of pathological fractures. J Bone Joint Surg 1976;58(8):1047-1055. 4. Kollender Y, Bickels J, Price WM, et al. Metastatic renal cell carcinoma of bone: indications and technique of surgical intervention. J Urol 2000;164:1505-1508. 5. Roscoe MW, McBroom RJ, Louis E, et al. Preoperative embolization in the treatment of osseous metastases from renal cell carcinoma. Clin Orthop Related Res 1989;238:302-307.

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Chapter 21 Posterior Flap Hemipelvectomy Martin M. Malawer James C. Wittig

BACKGROUND Despite increasingly effective chemotherapy and advances in limb-sparing surgery around the pelvis and hip, hindquarter amputation (hemipelvectomy) often remains the optimal surgical treatment for primary tumors of the upper thigh, hip, or pelvis. Hemipelvectomy may also be lifesaving for patients with massive pelvic trauma or uncontrollable sepsis of the lower extremity, and it can provide significant palliation of uncontrollable metastatic lesions of the extremity.9,10,12 An intimate knowledge of the pelvic anatomy (FIG 1A,B) and a systematic approach to the surgical procedure are required to minimize the intraoperative and postoperative morbidity associated with this demanding procedure. Early descriptions of the surgical technique of hemipelvectomy emphasized the importance of careful selection of patients and immediate replacement of blood loss.2,4,5,7,8,13,14,15,17,18,19,21,22,23,24 Other, later technical descriptions of this procedure have been published.1,3,6,16

FIG 1 • A. Anatomy of the pelvis. B. Retroperitoneal space and significant anatomic structures. C. Types of hemipelvectomy. (Courtesy of Martin M. Malawer.) Current terminology for major amputations through the pelvis is overly simplistic and consequently confusing. The terms hindquarter amputation and hemipelvectomy are often used interchangeably to refer to any http://e-surg.com

amputation performed through the pelvis. Older terms used to describe this same procedure include

interpelviabdominal17 and interinnominoabdominal22 amputation to describe this same procedure. The advent of limb-sparing pelvic resections has necessitated a distinction between internal and external hemipelvectomy, depending on whether preservation of the ipsilateral limb is performed. Confusion caused by the term internal hemipelvectomy can be avoided by use of a standardized classification for pelvic resection. P.239 Sugarbaker and Ackerman23 and others have shown the use of a myocutaneous pedicle flap based on the femoral vessels and anterior compartment of the thigh for closure of the wound in patients with tumor involving the posterior buttock structures. This procedure has been termed an anterior flap hemipelvectomy to distinguish it from the more common posterior flap hemipelvectomy. Anterior flap hemipelvectomy is indicated for tumors that involve the buttock and for selected patients who require a well-vascularized flap for coverage. Other flaps have also been described. The adductor myocutaneous flap is used when anterior or posterior flaps are not possible to obtain.11 There are subtypes of the posterior flap hemipelvectomy. The term classic hemipelvectomy is used to refer to amputation of the pelvic ring via disarticulation of the pubic symphysis and the sacroiliac joint, division of the common iliac vessels, and closure with a posterior fasciocutaneous flap (FIG 1C). Classic hemipelvectomy is typically necessary for large tumors that arise within the pelvis.

Modified hemipelvectomy refers to a procedure that preserves the hypogastric (internal iliac) vessels and the inferior gluteal vessels supplying the gluteus maximus, permitting creation of a vascularized myocutaneous posterior flap for wound closure. This term also describes variations from the classic operation, including resection through the iliac wing or contralateral pubic rami. Modified hemipelvectomy is most commonly performed for tumors involving the thigh or hip when a limbsparing alternative is contraindicated. “Extended hemipelvectomy” refers to a resection of the hemipelvis through the sacral alar and neural foramina, thereby extending the margin for tumors that approach or involve the sacroiliac joint (FIG 2). Regardless of the type of flap created for closure, the term compound hemipelvectomy is used to describe resection of contiguous visceral structures such as bladder, rectum, prostate, or uterus. (Tumor suspected of extending into viscera or extremely large tumors filling the pelvic fossa can be approached through an intraperitoneal incision.).

ANATOMY The skeletal anatomy and contents of the pelvis are complex and difficult to visualize without direct experience. Major portions of the gastrointestinal tract, the urinary tract, the reproductive organs, and the neurovascular trunks to the extremities all coexist within the confines of the bony pelvis. Understanding the three-dimensional anatomy is essential to identifying and protecting these structures during a hemipelvectomy (see FIG 1). The normal anatomy may be distorted by the tumor. Reference to easily palpable and visual landmarks helps identify critical structures. The surgical approach to a hemipelvectomy is based on sequential exposure and identification of these landmarks and structures. http://e-surg.com

Bony Anatomy The basic pelvic bony anatomy is best thought of as a ring running from the posterior sacrum to the anterior pubic symphysis. Major joints include the large, flat sacroiliac joints; the hip joints; and the pubic symphysis. The hip joint is easily located by motion of the extremity; the other joints are easily located and identified by palpation. Other easily palpable bony prominences include the iliac crest, the anterior superior iliac spine, the ischial tuberosity, and the greater trochanter of the femur. These landmarks are essential in creating rational skin incisions during the procedure. Likewise, identification of internal bony landmarks helps localize adjacent structures. The lumbosacral plexus is found by palpating the sacroiliac joint, the sciatic nerve and gluteal vessels are found under the sciatic notch, and the urethra is found under the arch of the pubic symphysis.

Vascular Anatomy Ligation of the correct pelvic vessels is crucial to a successful amputation. The importance of this fact is indicated by the classification scheme, in which the level of ligation determines the type of amputation to be performed. As the abdominal aorta and vena cava descend into the pelvis, they bifurcate, creating the common iliac arteries and veins. This bifurcation typically occurs at L4, with the lower bifurcation occurring at S1. The left-sided aorta and the iliac and external iliac arteries remain anterior to the major veins throughout the pelvis. The internal iliac artery (hypogastric artery) bifurcates from the posterior surface of the common iliac artery as it travels down toward the sciatic notch. Tumor masses within the pelvis can distort this anatomy, making it mandatory to visualize and isolate each of the vessels before performing a ligation (see FIG 1A). The internal iliac (hypogastric) vessels supply the pelvic floor, rectum, bladder, and prostate as well as the gluteal muscles. Ligation of this vessel will not jeopardize the internal structures because of contralateral blood flow and rich anastomotic vessels; however, it will significantly devascularize the gluteus maximus muscle. Classic hemipelvectomy, in which these branches are divided, has a substantial rate of wound complications as a direct result.

Pelvic Viscera In addition to the critical vascular structures, major organs of the gastrointestinal and genitourinary tracts are present and exposed during a hemipelvectomy. These structures should be completely evaluated before surgery. The bladder and urethra, and the prostate in male patients, are located above and under the pubic symphysis. Placement of a Foley catheter with a large inflated balloon makes these structures easier to palpate during surgery. Care must be taken not to injure the urethra during division of the symphysis. In addition, the venous plexus surrounding the prostate can be a significant source of bleeding that can be difficult to control even with good visualization of the organ. The ureters are at risk of injury as they cross over the iliac vessels from lateral to medial. The peristaltic motion of the ureters helps to identify these structures. In female patients, the ovaries, fallopian tubes, uterus, cervix, and vagina require identification and protection. Care in P.240 P.241 taking a complete history of the patient will identify women who have undergone hysterectomies. In female patients who have not undergone such surgery, these organs are found under and adjacent to the bladder. http://e-surg.com

They can be easily and safely retracted out of the operative field.

FIG 2 • A. CT scan showing a large chondrosarcoma arising from the left proximal femur. Benign osteochondroma is on the ipsilateral femur. This patient had multiple hereditary osteochondromas. This is one of the more common indications for performing a hemipelvectomy. Chondrosarcoma is the most common malignant tumor of the pelvis. B. Pathologic fracture (distal location) through an extremely large renal cell carcinoma of the left pelvis. There is a large soft tissue component extending almost to the midline. C. Solitary renal cell carcinoma metastasis of the right proximal femur extending into the pelvis. This MRI shows a large extraosseous component with complete destruction of the periacetabular area and with tumor filling the ischiorectal space. Solitary renal cell carcinoma metastasis is considered to be one of the few indications for radical amputation due to metastatic carcinoma. D. Massive sarcoma recurrence of the right thigh following an above-knee amputation. E. Massive swelling of the right thigh following intramedullary rod placement. F. Plain radiograph showing extensive soft tissue swelling from the chondrosarcoma. There is minimal soft tissue calcification. G. Plain radiograph of the proximal femur showing the intramedullary rod extending from the hip distally with contamination of the entire lateral and aspect of the thigh. H. Gross specimen after hemipelvectomy showing an extremely large chondrosarcoma (arrows) arising from the proximal femur. http://e-surg.com

Most of the gastrointestinal tract is protected by the peritoneum and is gently retracted out of the operative field. Of particular concern is the sigmoid colon, which must be protected during left-sided amputations. The colon and rectum must also be identified and protected during the division of the sling muscles before completing the amputation. Insertion of a rectal tube before surgery helps to identify both these structures and to decompress them. Because of the possibility of bacterial contamination from these structures, preoperative bowel preparation and the use of appropriate antibiotics are prudent.

INDICATIONS Unresponsive Sarcomas Involving Multiple Compartments The most common indication for hemipelvectomy is a nonmetastatic sarcoma that fails to respond to neoadjuvant chemotherapy or radiation. In addition, patients with extremely large sarcomas involving multiple compartments of the thigh may require an immediate amputation to avoid tumor fungation, hemorrhage, and secondary infection. In each case, the type of hemipelvectomy performed is dictated by the anatomic location of the tumor and the expected defect to be created by the resection. For example, a posterior tumor involving the buttock and sciatic nerve that cannot be resected by a buttockectomy can be removed and closed with a vascularized pedicle anterior flap hemipelvectomy.

Contamination of Surrounding Structures Patients with extensive contamination of compartments from inappropriately placed biopsies or from unplanned intralesional resections of sarcomas around the pelvis, hip, and proximal thigh are candidates for hemipelvectomy. In addition, pathologic fractures of the proximal femur often contaminate unexpectedly large volumes of tissue (see FIG 2). Traditionally, such fractures have been treated with hemipelvectomy, although some institutions now attempt limb-sparing procedures after aggressive preoperative (neoadjuvant) treatment and spica immobilization.

Nonviable Extremity Precluding Limb Salvage Elderly patients with significant peripheral vascular disease and patients with fungating, infected sarcomas that preclude limb-sparing surgery may be candidates for hemipelvectomy. Conversely, very young and skeletally immature children with primary sarcomas who are not suitable candidates for limb-sparing procedures because of the inevitable problem of limb length discrepancy may be treated with hemipelvectomy. Typically, the youngest patients adapt most completely to their missing limb and lead extremely active lives. Psychological counseling for the parents and family is essential under such circumstances.

Failure of Previous Resection Hemipelvectomy is indicated as a final salvage procedure for patients with local recurrence in the thigh or buttock after aggressive surgical and medical treatment. Careful patient evaluation is necessary to rule out metastatic disease in such cases. Hemipelvectomy may also be required to control infection after limb-sparing procedures around the hip and pelvis.

Palliation The use of radical amputation for palliation of patients with metastatic disease is rare. Palliative indications for hemipelvectomy include uncontrollable pain from tumor involvement of the lumbosacral http://e-surg.com

plexus and sciatic and femoral nerves. Patients with uncontrollable local disease from metastatic carcinoma who have failed to respond to all conventional treatments, including radiation and chemotherapy, may also benefit from amputation. Realistic expectations and psychological support for the patient and family are essential in such cases.

Nononcologic Indications Modified or anterior flap hemipelvectomy may be required for uncontrolled decubiti and osteomyelitis of the hip and pelvis in patients with long-standing paralytic conditions. Both function and emotional wellbeing often improve rapidly after the source of chronic sepsis has been surgically removed. For patients with partial pelvic amputation and open hemorrhaging fractures of the pelvis, emergency hemipelvectomy may be lifesaving. In both circumstances, oncologic margins are not required, making the surgery easier to perform.

IMAGING AND OTHER STAGING STUDIES Complete imaging and staging of the patient are essential for proper patient selection and preoperative planning. Routine preoperative staging studies of the patient should include a computed tomography (CT) scan of the chest and a total body bone scan to detect metastatic disease. Images of the liver and abdomen may be indicated for patients with certain tumors, such as myxoid liposarcomas that can present with unusual sites of metastases.

Standard Radiographs Radiographs remain the gold standard for the detection and diagnosis of bone sarcomas. Evaluation of patients with suspected pelvic and hip or thigh tumors should always include a standard anteroposterior (AP) pelvis view that extends from the top of the iliac crests to below the pubic symphysis. Additional views of the pelvis may be helpful, including the iliac and obturator oblique views described by Judet as well as inlet and outlet views. Given the complexity of pelvic anatomy, cross-sectional images are vital. P.242

Computed Tomography and Magnetic Resonance Imaging CT and magnetic resonance imaging (MRI) both provide the ability to image pelvic anatomy in cross-sectional planes. MRI provides better images in the sagittal and coronal planes. Use of oral, intravenous, and rectal contrast media can greatly improve the ability of CT scanning to image the visceral organs of the pelvis. CT is extremely useful in evaluating the sacroiliac joint, the sciatic notch, and the symphysis pubis. MRI often provides a better image of the soft tissue and the intramedullary extent of sarcoma. The retroperitoneal lymph nodes can be evaluated with either technique. Because of the complementary nature of the information provided by these scans, a complete evaluation may require both imaging modalities.

Angiography Preoperative angiography of the pelvis is extremely useful in delineating the relationship of the iliac branches to the tumor. Older patients undergoing anterior flap hemipelvectomy may have silent atherosclerotic disease of the femoral vessels that could jeopardize the success of the flap. http://e-surg.com

If a modified hemipelvectomy is being considered, angiography reveals the level of the common iliac bifurcation. Patients undergoing palliative amputation may benefit from preoperative embolization to reduce intraoperative bleeding.

Venography and Other Tests Complete evaluation of the visceral structures of the pelvis may require additional studies. Dedicated radiographic evaluation using contrast materials of the colon, rectum, bladder, urethra, and uterus is useful if tumor involvement is suspected. Direct visual inspection by sigmoidoscopy and cystoscopy may be essential in selected patients. Pelvic venography should be performed if there is any clinical suspicion of venous obstruction (ie, distal edema). Venous tumor thrombi often occur with large pelvic chondrosarcomas. Tumor thrombi should be removed during surgery.

Biopsy The biopsy of tumors around the pelvis and proximal femur must be extremely well planned to avoid contaminating the posterior flap, which is the most common type of hemipelvectomy performed. The orthopaedic oncologist who will be performing the amputation should be present during the biopsy procedure to ensure that a proper and appropriately placed biopsy is performed (FIG 3).

FIG 3 • The biopsy of tumors around the pelvis and proximal femur must be extremely well planned to avoid contaminating the posterior flap, which is the most common type of hemipelvectomy performed. The posterior flap of the hemipelvectomy includes either the subcutaneous flap over the gluteus maximus or, if a modified posterior flap hemipelvectomy is performed, the above as well as the underlying gluteus maximus muscle.

SURGICAL MANAGEMENT Positioning http://e-surg.com

The patient is placed in a modified semisupine position. Incision of the abdominal wall and retroperitoneal dissection of the iliac vessels are performed first. The common iliac, external iliac, or internal iliac (hypogastric) vessels are selectively ligated according to the type of hemipelvectomy to be performed.

Approach Exposure of the pubis, bladder neck, and urethra permits sectioning of the symphysis pubis. The iliac wing, sacroiliac joint, or sacrum is then exposed and divided to complete the amputation. Division of the lumbosacral plexus at the level of the sacrum or pelvis is accomplished at the same time. A fasciocutaneous or a myocutaneous flap (involving the gluteus maximus for posterior flaps or the anterior compartment of the thigh for anterior flaps) is then completed. Flexion and adduction and abduction of the hip allow the surgeon to divide the muscles and ligaments of the pelvic floor and complete the amputation. The classic posterior flap hemipelvectomy can be visualized as consisting of five major surgical components. P.243

TECHNIQUES ▪ Anterior Retroperitoneal Approach through the Ilioinguinal Incision Through this incision (TECH FIG 1A), the retroperitoneal space is explored by detaching the abdominal wall musculature from above the ilioinguinal ligament and off the iliac crest (TECH FIG 1B). For large tumors of the ilium, the retroperitoneal space is entered laterally, where there is more free retroperitoneal fat.

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TECH FIG 1 • A. Ilioinguinal retroperitoneal incision and approach. The patient is placed on the operating table in a semisupine position. This permits anterior retroperitoneal surgery under an anterior approach. The perineal incision can then be performed with the hip abducted and flexed. The posterior gluteal incision is performed with the patient in a semilateral position in contrast to the typical lateral position frequently used. B. The retroperitoneal space is easily entered by detaching the abdominal wall musculature from above the ilioinguinal ligament and off the iliac crest. The peritoneum is then reflected off the tumor mass, and the retroperitoneal space is developed. It is crucial to identify all of the vascular structures initially to prevent any mistakes in ligation. C. A modified hemipelvectomy is an amputation preserving a portion of the wing of the ilium and the underlying gluteus maximus muscle and its major pedicle, the inferior gluteal vessels. The peritoneum is then reflected off the tumor mass, and the retroperitoneal space is developed. The ureter remains on the peritoneal reflection. The iliac arteries or hypogastric vessels are ligated and transected, the psoas muscle and the femoral nerve are transected, and the abdominal wall is released from the iliac crest from the symphysis pubis to the posterior superior iliac spine. http://e-surg.com

All structures are transected or mobilized anteriorly before proceeding to the next steps. P.244 It is crucial to identify all of the vascular structures initially to prevent any mistakes in ligation. The levels of transection and ligation of the iliac vessel, along with its two major branches (internal and external iliac vessels), are illustrated in the inset of TECH FIG 1B. A classic hemipelvectomy requires ligation of the common iliac artery and vein. A modified hemipelvectomy requires preservation of the hypogastric artery and specifically the first branch, the superior gluteal artery (TECH FIG 1C). The external iliac artery and vein are ligated. The anterior hemipelvectomy requires the external iliac artery to be intact; it is the main pedicle to the quadriceps muscle. Therefore, the hypogastric artery is ligated at its takeoff from the common iliac artery. The external iliac artery is not ligated.

▪ Perineal Incision The second major step is the perineal incision, which extends from the symphysis pubis down to the ischium along the inferior pubic ramus. The ischiorectal space is exposed along the inferior pubic ramus to the symphysis pubis. The symphysis pubis is disarticulated. The bladder is retracted with a malleable retractor, and an additional small malleable retractor is placed beneath the symphysis pubis notch to protect the urethra. The urethra is easily palpable and protected with a malleable retractor (TECH FIG 2). A Foley catheter is in place. For large tumors of the pelvic floor, the urethra may be around the pseudocapsule of the tumor. Therefore, great care must be taken not to enter the tumor or the pericapsular structures of the prostate.

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TECH FIG 2 • The perineal incision is then begun prior to abducting or flexing the affected extremity. The symphysis pubis is opened with a small osteotome or a cutting cautery.

▪ Posterior Flap Retrogluteal Area Exploration The third component of the procedure is the posterior fasciocutaneous or subcutaneous flap that is mobilized along the iliotibial band and the greater trochanter toward the sacroiliac joint. A classic hemipelvectomy involves the removal of all gluteal structures, and only the subcutaneous flap remains (TECH FIG 3). A classic hemipelvectomy consists of a disarticulation of the sacroiliac joint, therefore requiring all of the abdominal muscles to be released up to the paraspinal muscles. The iliolumbar ligament is a good surgical landmark: It inserts onto the ilium posteriorly just above the superior aspect of the sacroiliac joint. This is especially useful in obese patients in whom the sacroiliac joint cannot easily be palpated. P.245 http://e-surg.com

TECH FIG 3 • A. The abdominal wall musculature is released from the crest of the ilium with a 1- to 2-cm cuff of muscle remaining along the ilium. B. The psoas muscle has a tendency to bleed postoperatively and should therefore be oversewn. Depending on the type of hemipelvectomy to be performed (classical or modified), the level of the abdominal wall musculature release and the level of the posterior osteotomy will vary.

▪ Detachment of Pelvic Floor Musculature This maneuver is performed with the hip abducted and flexed, with the surgeon standing between the two extremities, facing the pelvis. While the assistant abducts the extremity, the pelvic floor musculature is stretched and ligated through Kelly clamps, beginning at the pubic ramus and ending at the sacroiliac joint (TECH FIG 4).

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TECH FIG 4 • A. Completion of amputation and release of pelvic floor muscles. The final steps of the amputation involve the release of the sacroiliac joint and the remaining pelvic sling muscles attaching to the ilium and pelvic floor. (continued) P.246

TECH FIG 4 • (continued) B. Gross specimen following hemipelvectomy for multiple recurrences of metastatic renal cell carcinoma. Small arrows indicate recurrent tumor; large arrows indicate intramedullary tract site. C. This tumor has crossed several anatomic boundaries and involves the anterior, posterior, and http://e-surg.com

medial compartments of the thigh. Large arrowhead indicates the location of the femur, small arrowheads indicate intervascular septa.(Courtesy of Martin M. Malawer.)

▪ Completion of the Amputation with Sacroiliac Disarticulation The amputation is completed by transecting the sacroiliac joint with a large osteotome while retracting the peritoneal contents and avoiding the previously transected iliac vessels. The surgical assistant stands on the same side of the table as the surgeon and flexes and abducts the lower extremity to expose the pelvic floor muscles for the surgeon. A sponge on a stick is used to push the rectum off the pelvic sling muscles in the inferior portion of the wound. If a left-sided hemipelvectomy is performed, great care must be taken to mobilize the rectum to avoid injuring it. The sling muscles are clamped with Kelly clamps and transected . The anterior capsule of the sacroiliac joint and, occasionally, some of the sacrolumbar trunks are the only remaining structures that must be opened and released. The sacroiliac joint is not opened previously due to the potential for bleeding from injury to the perisacral veins. If a posterior modified hemipelvectomy is performed, the wing of the ilium is transected from the sciatic notch to the midportion of the ilium. The hypogastric artery is preserved and the external iliac artery is ligated. The choice between a classic hemipelvectomy and a modified posterior flap hemipelvectomy is made preoperatively. In general, modified hemipelvectomies are performed for thigh and groin lesions, whereas classic hemipelvectomies are performed for true pelvic tumors of the muscle or bony structures (TECH FIG 5A). A modified hemipelvectomy preserves a portion of the wing of the ilium and the underlying gluteus maximus muscle and its major pedicle, the inferior gluteal vessels. Therefore, an osteotomy is performed through the wing of the ilium starting at the sciatic notch. The iliacus muscle is transected internally and the abductor muscles are transected longitudinally (posteriorly). All of the muscles located anteriorly in the pelvis are transected at this step. The sacroiliac joint is also identified anteriorly and the vessels are mobilized off the sacroiliac joint in preparation for the sacroiliac disarticulation that is the final step of the operative procedure. Closure of the flap is then performed over large 28-gauge chest tubes with suction drainage (TECH FIG 5B). Marcaine epineural catheters are used for continuous pain relief postoperatively (TECH FIG 5C). Two catheters are used: One is inserted into the lumbosacral plexus and the other into the femoral nerve. The wound is closed by rotating and suturing the prepared myocutaneous flap to the abdominal wall and flank. P.247

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TECH FIG 5 • A. Variation of a posterior flap for a modified posterior flap hemipelvectomy. A modified posterior flap hemipelvectomy is an amputation through the wing of the ilium with preservation of the gluteus maximus and its major pedicle and the inferior gluteus vessels. B. Skin closure. A large 28-gauge chest tube is used for drainage. C. Postoperative radiograph of an extended hemipelvectomy (the sacral alar is absent) with contrast injection of the Marcaine catheters that were placed perineurally along the femoral nerve sheath as well as the lumbar sacral plexus. F, femoral nerve; S, sciatic nerve; arrow indicates Renografin (contrast) in sciatic sheath. (Courtesy of Martin M. Malawer.)

PEARLS AND PITFALLS Preoperative

▪ Minimizing the morbidity and mortality associated with hemipelvectomy requires careful physical and psychological preparation of the patient. Patients receiving preoperative chemotherapy or radiation therapy require time to recover from their neutropenia and anemia. Use of supportive growth factors such as erythropoietin and granulocyte colony-stimulating factor may be of significant benefit. Replacing red cell mass by blood transfusion and correcting bleeding abnormalities are essential to reduce the risk of intraoperative mortality. ▪ Patients with poor nutrition secondary to disease and the nausea and vomiting induced by chemotherapy may require hyperalimentation before and after surgery to reduce problems with wound healing.

Intraoperative

▪ To reduce the risk of postoperative infection, bowel preparation should be performed for all patients. ▪ Perioperative antibiotic coverage for aerobic skin flora and anaerobic bowel flora is required.

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▪ If the tumor encases or involves the major vessels, extensive bleeding should be anticipated. Extensive blood loss and replacement in excess of one to two times the patient's circulatory volume may create life-threatening coagulopathies and pulmonary complications. ▪ Intraoperative retraction of the peritoneum and use of postoperative narcotics contribute to the development of an ileus that may last for a week or more. Postoperative

▪ Postoperative care to prevent hematomas and seromas includes the use of large-bore suction drains and pressure dressings using Ace wraps. A Foley catheter and a nasogastric tube are used to prevent abdominal distention; this reduces pressure on the skin closure. Skin sutures or staples should be retained for 3-4 weeks to minimize the risk of wound dehiscence. ▪ Routine placement of a nasogastric tube and avoidance of oral feeding are required to prevent nausea, vomiting, aspiration, abdominal distention, and wound complications. Early intravenous nutritional supplementation should be considered. ▪ Patients undergoing hemipelvectomy face a unique combination of psychological stress related to the loss of limb and potential loss of life from the underlying disease. Ongoing psychological support for the patient and family is essential. ▪ Division of the sacral plexus may result in loss of innervation of the ipsilateral bladder and penis, resulting in bladder atony and impotence. These problems are often transient and often resolve within 1 to 3 months as the contralateral innervation becomes dominant. An indwelling Foley catheter should be maintained until the patient becomes mobile, and postvoid residuals should be measured once the catheter is removed. ▪ A prosthesis should be offered to all patients, even though not all of them may use it. If a segment of ilium has been preserved, a suspension belt may be used.

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POSTOPERATIVE CARE The patient should understand that phantom limb sensations are to be expected and that they can be treated with analgesics. The discomfort will lessen over time. Although successful rehabilitation depends to a great extent on the patient's attitude, the physiatrist can help tremendously in these efforts. A positive attitude toward functional recovery augmented by early postoperative ambulation may move the patient rapidly to his or her goals. A positive approach is amplified by contact with other patients who have met some of the rehabilitation challenges. This can provide an immeasurable psychological boost to the patient. The oncologist, rehabilitation therapist, and others involved in the postoperative care must coordinate their efforts carefully.

OUTCOMES Most patients can ambulate after appropriate rehabilitation and use of hemipelvectomy prostheses.

FIG 4 • A. A patient 5 years after a hemipelvectomy playing golf, using the golf cart as a brace. B. Plain http://e-surg.com

radiograph showing one of the longest follow-ups (23 years) after modified posterior flap hemipelvectomy. This patient still ambulates well with a hemipelvectomy prosthesis. The remaining portion of the left ilium provides an area for the hemipelvectomy prosthesis to rest against. Most patients who survive their disease will go on to enjoy a high quality of life and participate in a multitude of recreational activities (FIG 4). Recent reports of series of hemipelvectomy patients have shown that this procedure has a low mortality rate and offers an acceptable survival in carefully selected patients. Quality-of-life studies suggest that long-term morbidity in patients who have undergone this radical amputation is not greater than that experienced by patients who have undergone other cancer treatments. Elderly and overweight patients may become wheelchair dependent after this procedure because of the increased workload required to ambulate. Some children and adults find that a prosthesis slows their ability to ambulate with crutches. However, a prosthesis enables the wearer to stand for prolonged periods of time without supports and frees both hands for other activities.

COMPLICATIONS All patients undergoing hemipelvectomy will have considerable phantom limb sensation. It may be a more disruptive P.249 long-term problem to the patient than the loss of the limb itself. Patient education, aggressive medical treatment, and rigorous physical rehabilitation play a role in minimizing the impact of these sensations. Injection and infusion of local anesthetics into the lumbosacral plexus and stumps of the sciatic and femoral nerves may significantly reduce actual pain and phantom sensation in the immediate postoperative period. Another serious postoperative complication is wound necrosis. Ligation of the common iliac vessels during a classic posterior flap hemipelvectomy deprives the flap of its major blood supply; 10% to 50% of patients develop clinically significant ischemia. Pressure from prolonged lying or sitting on the flap may result in ischemic necrosis. Early identification of necrosis and surgical revision is essential to minimize additional complications. Meticulous attention to preserving the fasciocutaneous vessels and a portion of the gluteus maximus can reduce the incidence of ischemic necrosis.20 All patients undergoing hemipelvectomy have significant risk factors for infection, such as tumor-related catabolism, chronic malnutrition, and chemotherapy-induced anemia and neutropenia. As a result, it is not surprising that infection is seen in about 15% of patients. Other factors that increase the risk of infection include immunosuppression from surgical stress, transfusions, and psychological depression. The length of the surgery is directly proportional to the extent of soft tissue involvement. Steps to reduce the incidence of infection should include the use of preoperative bowel preparation, use of a purse-string suture to close the anus during surgery, broad-spectrum perioperative antibiotic coverage, and the use of large-bore closed suction drains to prevent retroperitoneal hematomas. Infection may significantly retard wound healing; aggressive surgical débridement and prolonged dressing changes are often necessary.

REFERENCES http://e-surg.com

1. Banks SW, Coleman S. Hemipelvectomy: surgical techniques. J Bone Joint Surg 1956;384:1147-1155. 2. Beck NR, Bickel WH. Interinnomino-abdominal amputations: report of twelve cases. J Bone Joint Surg Am 1948;30A:201-209. 3. Francis KC. Radical amputations. In: Nora PF, ed. Operative Surgery. Philadelphia: Lea & Febiger, 1974. 4. Gordon-Taylor G. The technique and management of the “hindquarter” amputation. Br J Surg 1952;39:536-541. 5. Gordon-Taylor G, Wiles P. Interinnomino-abdominal (hindquarter) amputation. Br J Surg 1935;22:671-681. 6. Higinbotham NL, Marcove RC, Casson P. Hemipelvectomy: a clinical study of 100 cases with a 5-year follow-up on 60 patients. Surgery 1966;59:706-708. 7. King D, Steelquist J. Transiliac amputation. J Bone Joint Surg Am 1943;25A:351-367. 8. Leighton WE. Interpelviabdominal amputation. Report of three cases. Arch Surg 1942;45:913-923. 9. Malawer MM, Buch RG, Thompson WE, et al. Major amputations done with palliative intent in the treatment of local bony complications associated with advanced cancer. J Surg Oncol 1991;47: 121-130. 10. Malawer MM, Zielinski CJ. Emergency hemipelvectomy in the control of life-threatening complications. Surgery 1983;93:778-785. 11. Marfori ML, Wang EH. Adductor myocutaneous flap coverage for hip and pelvic disarticulations of sarcomas with buttock contamination. Clin Orthop Relat Res 2011;469(1):257-263. 12. Merimsky O, Kollender Y, Inbar M, et al. Palliative major amputation and quality of life in cancer patients. Acta Oncol 1997;36:151-157. 13. Morton JJ. Interinnomino-abdominal (hindquarter) amputation. Ann Surg 1942;115:628-646. 14. Pack GT, Ehrlich HE. Exarticulation of the lower extremity for malignant tumors: hip joint disarticulation (with and without deep iliac dissection) and sacroiliac disarticulation (hemipelvectomy). Ann Surg 1949;58:867-874. 15. Pack GT, Ehrlich HE, De C Gentile F. Radical amputations of the extremities in the treatment of cancer. Surg Gynecol Obstet 1947;84:1105-1116. 16. Phelan JT, Nadler SH. A technique of hemipelvectomy. Surg Gynecol Obstet 1964;119:311-318. 17. Pringle JH. The interpelvic-abdominal amputation; notes on two cases. Br J Surg 1916;4:283-295. http://e-surg.com

18. Ravitch MM. Hemipelvectomy. Surgery 1949;26:199-207. 19. Saint JH. The hindquarter (interinnomino-abdominal) amputation. Am J Surg 1950;80:142-160. 20. Senchenkov A, Moran SL, Petty PM, et al. Predictors of complications and outcomes of external hemipelvectomy wounds: account of 160 consecutive cases. Ann Surg Oncol 2008;15(1):355-363. 21. Slocum DB. An Atlas of Amputations. St. Louis: CV Mosby, 1949: 244-249. 22. Speed K. Hemipelvectomy. Ann Surg 1932;95:167-73. 23. Sugarbaker ED, Ackerman LV. Disarticulation of the innominate bone for malignant tumors of the pelvic parietes and upper thigh. Surg Gynecol Obstet 1945;81:36-52. 24. Wise RA. Hemipelvectomy for malignant tumors of the bony pelvis and upper part of the thigh. Arch Surg 1949;58:867-874.

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Chapter 22 Anterior Flap Hemipelvectomy Martin M. Malawer James C. Wittig

BACKGROUND The anterior flap hemipelvectomy is a modified version of the classic posterior flap hemipelvectomy. Instead of using the traditional posterior skin flap of the gluteal region, a myocutaneous flap from the anterior thigh is used to close the peritoneum after amputation through the sacroiliac joint and the pubic symphysis. This modification has permitted the treatment of difficult buttock and pelvic tumors where the posterior flap was involved or contaminated by tumor. Patients with extensive soft tissue sarcomas of the buttock or bone sarcomas of the pelvis that extend posteriorly, once thought to be incurable by standard posterior flap hemipelvectomy, can often be treated with an anterior flap hemipelvectomy. The procedure, which originally entailed use of an anterior skin flap raised off a portion of the superficial femoral vessels,1 was modified to include a full-thickness myocutaneous flap raised from the anterior thigh.2,7 The major advantage of anterior flap hemipelvectomy is the creation of a large vascularized myocutaneous flap that is ideal for closure of significant posterior defects (FIG 1). As much of the anterior thigh compartment may be saved as needed, depending on the size of the defect being closed. As always, careful patient selection is critical in ensuring that an acceptable outcome is achieved. For example, elderly patients and diabetics with silent atherosclerotic disease of femoral vessels must be carefully evaluated with preoperative angiography. The hemipelvectomy procedures described in the previous chapter require a flap of buttock skin to cover the surgical defect. Anterior flap hemipelvectomy allows sacrifice of the entire buttock and all the overlying skin and soft tissue to the midline. Even patients who have a tumor-contaminated buttock to the midline may have a potentially curative procedure.11,12 If possible, tumors in this area, especially those of low histologic grade, should be treated with an excision of the gluteus maximus muscle (buttockectomy). However, if tumor extends through the gluteus maximus muscle to involve the gluteus medius or minimus, if tumor encases the sciatic nerve, or if tumor is directly adjacent to the pelvic bones, a radical amputation using an anterior myocutaneous flap is indicated.

ANATOMY The surgeon must be familiar with the pelvic anatomy as well as the thigh musculature and femoral vessels. The anatomic key to this procedure is the major vascular pedicle of the pelvis and extremity. Oncologic considerations for tumor involvement of the bone or soft tissues in the pelvis are identical to those discussed in the chapter on posterior flap hemipelvectomy. The external iliac vessels leave the pelvis and cross through the femoral triangle where they become the common femoral vessels. A single branch supplying the iliac crest may be encountered along the medial aspect of the external iliac vessel just below the inguinal ligament. The superficial femoral vessels travel underneath the sartorius muscle along most of the length of the thigh; they pass through the adductor hiatus and become the popliteal vessels behind the knee. The major branch in the femoral triangle is the profunda http://e-surg.com

femoris, which arises from the posterior aspect of the superficial femoral vessel and passes deep to the posterior surface of the femur. Ligation of the profunda femoris is required to elevate the anterior flap. The common femoral and superficial femoral vessels are preserved. The (four) quadriceps muscles, the adductor muscles, and the sartorius muscle all have a vascular supply that arises from pedicles off the superficial femoral artery. Perforating branches from the profundus are present in the vastus lateralis and may be encountered as they pass through the intramuscular septum. The entire anterior and medial compartments can be elevated off the femur by dividing the quadriceps tendon above the patella and peeling the full-thickness myocutaneous flap off the anterior femoral periosteum.3,4,6 To prevent hemorrhage, care must be taken to properly ligate all perforating vessels, as well as the superficial femoral vessels, at the level of the adductor hiatus. Division of the skin at the inguinal canal and skeletonization of the external iliac vessels permit the entire flap to be rotated as necessary to cover the defect created by the amputation. Use of this flap for closure results in improved cosmesis and facilitates fitting of a prosthesis for an improved functional result.9,10,11 In addition, this flap permits radiation therapy to the remaining pelvis without any wound complications. The nature of the flap available for closure permits greater posterior resection than that possible during a traditional posterior flap hemipelvectomy. The entire buttock compartment (ie, the gluteal muscles, sciatic nerve, sacrospinous ligaments, and sacral alar) can be safely removed. The anterior myocutaneous flap consists of a portion of or the entire quadriceps muscle group on its vascular pedicle, the superficial femoral artery.4 This flap covers the entire peritoneal surface and generally heals with minimal problems.

IMAGING AND OTHER STAGING STUDIES In addition to the routine radiographic evaluation of the pelvis (radiography, computed tomography [CT] and magnetic resonance imaging [MRI], and bone scanning) necessary P.251 to determine the patient's suitability for a hemipelvectomy, angiography of the femoral vessels is essential for patients undergoing anterior flap hemipelvectomy.

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FIG 1 • Clinical photograph showing a sarcoma recurrence in the posterior thigh with local tumor fungation after surgery and radiation therapy. The old posterior incision is visible (arrow). This is a classic indication for an anterior flap hemipelvectomy, which is used instead of the classic posterior flap hemipelvectomy. (Courtesy of Martin M. Malawer.) The variable nature of the profunda femoris, as well as the frequent presence of silent atherosclerosis of the superficial femoral artery in elderly patients or in patients with a history of smoking, can greatly affect the outcome of this procedure. In addition, visualization of the pelvic vessels can help to ensure that they are not involved with the tumor. CT and MRI are required to determine whether the tumor involves the sacrum or the vertebra. Spinal involvement is a contraindication to this procedure (FIG 2).

INDICATIONS Anterior flap hemipelvectomy is indicated for tumors involving the buttock that cannot be resected with a less radical procedure. Patients who have failed to respond to prior attempts at limb-sparing surgery, with or without radiation, or who have tumors that primarily involve the posterior thigh and sciatic nerve are also candidates for this procedure. This procedure may also be indicated after failed attempts at limb-sparing surgery5 as well as for patients with nononcologic indications for amputation8 (eg, uncontrollable sepsis from sacral or trochanteric osteomyelitis).

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FIG 2 • CT scan showing a large extraosseous chondrosarcoma of the buttock (Tu) with a thin rim of gluteus maximus muscle remaining (G). There is early intrapelvic extension through the sciatic notch (arrow). (Courtesy of Martin M. Malawer.)

FIG 3 • A. Clinical photograph of anterior flap drawn before surgery. The anterior myocutaneous flap consists of a large portion of the anterior thigh skin, subcutaneous tissue, and underlying quadriceps muscle. This flap is based on the common femoral and superficial femoral artery. The profundus artery is ligated when raising this flap. The incision extends along the medial aspect of the thigh below the sartorius so that the superficial femoral artery can be identified and ligated distally to preserve adequate vascularity to the quadriceps. The transverse incision is performed several inches above the knee. B. The posterior incision outlined extends from the anterior flap and follows the sacroiliac joint down to the gluteal crease. It then travels transverse posteriorly to meet the anterior flap. This incision avoids any contamination of the posterior incision. This procedure was developed by Dr. Paul H. Sugarbaker at the National Cancer Institute during the 1980s. C. Intraoperative photograph showing a large myocutaneous quadriceps flap elevated off the femur as the first operative stage during an anterior flap hemipelvectomy. The profundus femoris artery is ligated so that the flap can be raised above the inguinal ligament and the retroperitoneal approach of the hemipelvectomy can proceed. (Courtesy of Martin M. Malawer.) Nononcologic indications include selected paraplegics with uncontrollable chronic osteomyelitis of the pelvis or hip joint.

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SURGICAL MANAGEMENT Preoperative Planning Careful presurgical planning is necessary to achieve optimal results. The planned surgical incision is drawn before any cutting to visualize the separate components of the anterior flap hemipelvectomy incisions (FIG 3). Preoperative preparations include correction of blood deficits and a complete bowel preparation. In females, the vagina is also prepared. Venous and arterial lines are secured, and a drainage catheter is placed in the bladder.

Positioning After being placed supine on the operating table, the patient is rolled into the lateral position, with the iliac crest at the flexion point of the table (FIG 4). As the patient is positioned, a cushion is placed beneath the iliac crest and greater trochanter to prevent pressure necrosis of the skin. Padding beneath the axilla is used to allow full excursion of the chest wall and to prevent injury to the brachial plexus. P.252 The arm is placed on a Krasky arm rest. An elastic wrapping or a support stocking is used to prevent blood from pooling in the contralateral lower extremity. The operating room table is flexed to open the angle between the crest of the ilium and the lumbar vertebrae. The anus is sutured shut. The lower extremity is prepared and draped free, with the skin exposed circumferentially from the knee to the iliac crest.

FIG 4 • Positioning the patient. (Courtesy of Martin M. Malawer.)

TECHNIQUES ▪ Anterior and Posterior Skin Incisions Before the operation, the surgeon must ensure that the myocutaneous flap created from the tissue http://e-surg.com

overlying the quadriceps muscle will cover the operative defect created in the buttock. The location of the proposed incision is mapped out with a marking pen and the width and length of the flap are compared with the anticipated defect in the buttock. Once it is ascertained that the flap is adequate to cover the defect, the remainder of the incision is determined (TECH FIG 1). First, the location of the incision is drawn medially to the tumor at or near the midline posteriorly above the anus. Superiorly and laterally, the incision should parallel the wing of the ilium to the anterior superior iliac spine. It then continues distally along the midpoint of the lateral aspect of the thigh to the junction of the lower and middle thirds of the thigh. The medial incision courses 2 to 3 cm lateral to the anus, then anteriorly in the gluteal crease toward the pubic tubercle. It continues along the midpoint of the thigh to the junction of the lower and middle thirds of the thigh. The two longitudinal incisions extending along the lateral and medial aspects of the thigh are connected by a transverse incision over the anterior aspect of the thigh. The location of this transverse incision determines the length of the myocutaneous flap. Hence, the transverse incision is positioned so the tip of the flap will extend to the level of the iliac crest.

TECH FIG 1 • Incision. (Courtesy of Martin M. Malawer.)

▪ Posterior Dissection in the Ischiorectal Space In excision of buttock tumors, the medial margin of the tumor is usually the closest one to the line of excision. Therefore, the dissection should commence medial to the tumor to allow the surgeon to assess operability before completion of the amputation is required (TECH FIG 2). The initial incision is made superficial to the sacrum in the midline through fascia to the midsacral spines. A cuff of skin 2 to 3 cm long is preserved around the anus. The sacral attachments of the gluteus maximus and erector spinae muscles are divided from their origins between the midsacral spines and the dorsal sacral foramina. Biopsies from the medial margin of resection are secured. By removing the outer table from the sacrum, biopsies from sacral nerves may also be obtained if indicated. If by cryostat sectioning and histologic examination these biopsies are negative, the amputation may proceed.

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TECH FIG 2 • Posterior incision to determine operability. (Courtesy of Martin M. Malawer.) P.253

▪ Lateral Incision of the Myocutaneous Flap Abdominal and back muscles that arise on the sacrum and the iliac crest are incised in the plane of attachment of muscle to bone to minimize blood loss. Muscles to be cut include the external oblique, erector spinae, latissimus dorsi, and quadratus lumborum (TECH FIG 3).

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TECH FIG 3 • Release of the back muscles of the iliac crest. (Courtesy of Martin M. Malawer.)

▪ Transection of the Superficial Femoral Artery The extremity is flexed at the hip to place the tissues in the area of the gluteal crease under tension. The perianal incision is extended toward the pubic tubercle along the gluteal crease. The deep dissection is continued lateral to the rectum into the ischiorectal fossa. The remaining origins of the gluteus maximus muscle are now severed from the coccyx and sacrotuberous ligament (TECH FIG 4).

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TECH FIG 4 • Posterior dissection in the ischiorectal space. (Courtesy of Martin M. Malawer.)

▪ Release of the Vastus Lateralis The surgeon now moves from the posterior to the anterior aspect of the patient. The anterior incision at the junction of the middle and lower thirds of the thigh is made and continued down to the femur, transecting the entire quadriceps muscle (TECH FIG 5). Laterally, this incision is continued superiorly toward the greater trochanter to the anterior superior iliac spine. The tensor fascia lata muscle is separated from its investing fascia so that it is included with the specimen.

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TECH FIG 5 • Lateral incision of the myocutaneous flap. (Courtesy of Martin M. Malawer.) P.254

▪ Transection of the Superficial Femoral Artery The fascial covering of the vastus lateralis of the quadriceps femoris muscle is dissected free of the flexor muscles and traced to its insertion on the femur. Then, the vastus lateralis is severed from the femur using electrocautery. In performing the dissection from this point on, care must be taken not to separate muscle bundles of the myocutaneous flap from the overlying skin and subcutaneous tissue (TECH FIG 6).

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TECH FIG 6 • Release of the vastus lateralis from the femur. (Courtesy of Martin M. Malawer.)

▪ Release of the Quadriceps Muscle from the Femur The medial skin incision is from the area of Hunter canal to the pubic tubercle. The superficial femoral vessels are located at their point of entry into the abductor muscles and are ligated and divided at this level. These vessels course along the deep margin of the myocutaneous flap, and, in the subsequent dissection, they are traced superiorly to the inguinal ligament. Multiple small branches from the superficial femoral vessels to the abductor muscles must be clamped, divided, and ligated (TECH FIG 7).

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TECH FIG 7 • Transection of superficial femoral artery. (Courtesy of Martin M. Malawer.)

▪ Release of the Myocutaneous Flap from the Femur Vigorous upward traction on the myocutaneous flap allows the origins of the vastus intermedius and the vastus medialis to be severed from the femur. As the release of the myocutaneous flap continues up toward the pelvis, the profunda femoris vessels are identified. These vessels are ligated and divided at their origin from the common femoral artery (TECH FIG 8). The myocutaneous flap is freed from its pelvic attachments by the following procedure. The abdominal muscles and fascia are severed from the iliac crest. The sartorius muscle is transected at its origin on the anterior superior iliac spine. The rectus femoris is transected at its origin on the anterior inferior iliac spine. The femoral sheath overlying the hip joint is divided. The left rectus abdominis muscle is released from the pubic bone. By retracting the myocutaneous flap medially, full access to the pelvis is achieved. Blunt dissection along the femoral nerve allows rapid dissection into the pelvis to expose the vessels and nerves to be transected in the subsequent phases of the procedure. http://e-surg.com

P.255

TECH FIG 8 • A. Release of the quadriceps muscle from the femur. B. Release of the myocutaneous flap from the pelvis. (Courtesy of Martin M. Malawer.)

▪ Division of the Symphysis Pubis To divide the symphysis pubis, the bladder and urethra are protected and a scalpel is used to locate and divide the cartilaginous joint (TECH FIG 9).

TECH FIG 9 • Division of the symphysis pubis. (Courtesy of Martin M. Malawer.)

▪ Transection of the Iliac Vessels http://e-surg.com

The internal iliac artery and vein are divided at their point of origin from the common iliac vessels. Multiple visceral branches of the internal iliac vessels are divided in their course superficial to the sacral nerve roots. Strong medial traction on the viscera will help expose these vessels. When this phase of the dissection is completed, the nerve roots should be clearly visualized throughout their course in the pelvis (TECH FIG 10). The common iliac lymph nodes remain with the patient in this procedure, in contrast to a standard hemipelvectomy in which they are removed.

TECH FIG 10 • Transection of internal iliac vessels and branches. (Courtesy of Martin M. Malawer.) P.256

▪ Division of the Psoas Muscles and Nerve Roots The psoas muscle is divided near its junction with the iliacus muscle. The obturator nerve deep to the muscle is also divided. Care is taken to preserve the femoral nerve coursing into the myocutaneous flap. The lumbosacral and sacral nerve roots are ligated and divided close to the ventral sacral foramina (TECH FIG 11).

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TECH FIG 11 • Division of the psoas muscle and nerve roots. (Courtesy of Martin M. Malawer.)

▪ Division of the Pelvic Diaphragm and Sacrum The leg is elevated to place under tension the individual muscles that constitute the pelvic diaphragm. Care is taken to protect the urethra, bladder, and rectum. The urogenital diaphragm, levator, and piriformis muscles are divided. These muscles are transected near their pelvic attachments (TECH FIG 12). The surgeon should again change orientation and move back to the posterior aspect of the patient. Using an osteotome and commencing at the tip of the coccyx, the coccyx and sacrum are divided in a plane that bisects the sacral foramina.

TECH FIG 12 • A. Division of the pelvic diaphragm. B. Division of the sacrum. (Courtesy of Martin M. Malawer.) Initially, the course of the osteotome should parallel the midsacral spines. The surgeon, being posterior to http://e-surg.com

the patient, reaches around the coccyx with the left hand to locate the S5 neural foramina from within the sacrum. This is at the junction of the sacrum and the coccyx. By holding the osteotome with the right hand, the direction for bone transection can be precisely determined. The assistant drives the osteotome through the bone with the mallet. At the upper portion of the sacrum, care must be taken not to fracture inadvertently through the bone. The lumbosacral ligament is divided to release the specimen. P.257

▪ Closure The operative site and myocutaneous flap are copiously irrigated and bleeding points are secured. The myocutaneous flap is folded posteriorly into the operative defect over two sets of suction drains. The fascia of the quadriceps femoris is sutured to the musculature of the anterior abdominal wall, to the back muscle, to the sacrum, and to the muscles of the pelvic diaphragm. The skin is closed with interrupted sutures (TECH FIG 13).

TECH FIG 13 • Closure. (Courtesy of Martin M. Malawer.)

PEARLS AND PITFALLS Closure

▪ Sugarbaker5,8 and others1,2,4,9 have shown the use of a myocutaneous pedicle flap based on the femoral vessels and anterior compartment of the thigh for closure of the wound in patients with tumors involving the posterior buttock structures. ▪ The primary advantage of this procedure is that the anterior flap raised from the thigh can be used to reconstruct an enormous posterior defect with little risk of flap necrosis. Patients who are expected to require substantial doses of radiation postoperatively should be considered for this procedure whenever possible because the well-vascularized myocutaneous flap tolerates radiation well. ▪ Great care must be taken not to dissect or shear the subcutaneous tissue and skin overlying the quadriceps during the creation of the flap because this will compromise the cutaneous circulation. ▪ Occasionally, tumor tissue or heavily irradiated skin overlying the superficial femoral artery may require sacrifice of the skin pedicle. In this instance, the island myocutaneous flap should be used.

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POSTOPERATIVE CARE The patient should understand that phantom limb sensations are to be expected and that he or she can be treated with analgesics. The discomfort will lessen over time. Although successful rehabilitation depends to a great extent on the patient's attitude, the physiatrist can help tremendously in these efforts. A positive attitude toward functional recovery augmented by early postoperative ambulation may move the patient rapidly to his or her goals. A positive approach is amplified by contact with other patients who have met some of the rehabilitation challenges. This can provide an immeasurable psychological boost to the patient. The oncologist, rehabilitation therapist, and others involved in the postoperative care must coordinate their efforts carefully.

OUTCOMES The potential for rehabilitation with this procedure is excellent. Patients who are free of disease use a prosthesis regularly. Patients walk with the prosthesis without the use of crutches or a cane. Because of the vascular nature of this flap, the surgical wound heals rapidly in the vast majority of patients. Accordingly, the 10% to 30% risk of ischemic necrosis associated with posterior flap hemipelvectomy is not seen with an anterior flap procedure. Likewise, the risk of infection in the postoperative period is markedly reduced. However, some studies have shown that the design of the flap is not a factor with statistical significance in the number of wound infections or flap necrosis.8 Rehabilitative considerations and the risk of phantom pain are similar to those associated with other types of hemipelvectomies. Because of the rapid healing seen with this type of flap, prosthetic fitting may be performed earlier.

COMPLICATIONS Lengthy and extensive operations have shown association with the development of wound infection and flap necrosis. Early postoperative complications with this procedure have not occurred to date. The serious problem of skin flap ischemia seen in nearly 25% of patients undergoing a standard posterior flap hemipelvectomy, especially with the ligation of the common iliac vessels, has not been observed. The most bothersome long-term postoperative problem with this procedure (as with a standard hemipelvectomy) is phantom limb pain. Approximately 20% of patients currently surviving have severe phantom limb pain requiring narcotic analgesics on a daily basis. However, this incidence of phantom limb pain is not noticeably different from that seen with standard hemipelvectomy.

P.258

REFERENCES 1. Bowden L, Booher RJ. Surgical considerations in the treatment of sarcoma of the buttock. Cancer 1953;6:89-99. 2. Frey C, Matthews LS, Benjamin H, et al. A new technique for hemipelvectomy. Surg Gynecol Obstet http://e-surg.com

1976;143:753-756. 3. Gebhart M, Collignon A, Lejeune F. Modified hemipelvectomy: conservation of the upper iliac wing and an anterior musculocutaneous flap. Eur J Surg Oncol 1988;14:399-404. 4. Larson DL, Liang MD. The quadriceps musculocutaneous flap: a reliable, sensate flap for the hemipelvectomy defect. Plast Reconstr Surg 1983;72:347-354. 5. Lotze MT, Sugarbaker PH. Femoral artery based myocutaneous flap for hemipelvectomy closure: amputation after failed limb-sparing surgery and radiotherapy. Am J Surg 1985;150:625-630. 6. Luna-Perez P, Herrera L. Medial thigh myocutaneous flap for covering extended hemipelvectomy. Eur J Surg Oncol 1995;21:623-626. 7. Mnaymneh W, Temple W. Modified hemipelvectomy utilizing a long vascular myocutaneous thigh flap. J Bone Joint Surg Am 1980;62A: 1013-1015. 8. Senchenkov A, Moran SL, Petty PM, et al. Predictors of complications and outcomes of external hemipelvectomy wounds: account of 160 consecutive cases. Ann Surg Oncol 2008;15(1):355-363. 9. Sugarbaker PH, Chretien PA. Hemipelvectomy for buttock tumors utilizing an anterior myocutaneous flap of quadriceps femoris muscle. Ann Surg 1983;197:106-115. 10. Temple WJ, Mnaymneh W, Ketcham AS. The total thigh and rectus abdominis myocutaneous flap for closure of extensive hemipelvectomy defects. Cancer 1982;50:2524-2528. 11. Workman ML, Bailey DF, Cunningham BL. Popliteal-based filleted lower leg musculocutaneous free-flap coverage of a hemipelvectomy defect. Plast Reconstr Surg 1992;89:326-329. 12. Yamamoto Y, Minakawa H, Takeda N. Pelvic reconstruction with a free fillet lower leg flap. Plast Reconstr Surg 1997;99:143.

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Chapter 23 Hip Disarticulation and Creating an Above-Knee Amputation Stump after Hip Disarticulation Daria Brooks Terrell Amir Sternheim

BACKGROUND Hip disarticulation is an amputation of the lower extremity through the hip joint capsule. Although most tumors of the lower extremities are amenable to limb-sparing techniques, some tumors of the femur and thigh are so extensive that hip disarticulation is needed for adequate tumor resection.5,6,12 Disarticulation of the hip for malignant tumors is a rare operation, but it is still needed instead of an aboveknee amputation if the tumor cannot be resected using a limbsalvage procedure due to proximal transosseous skip metastases, pathologic fractures, extensive diaphyseal extension, and large adjacent soft tissue masses combined with a poor response to chemotherapy.1,11,14 With advances in prosthetic design, patients can ambulate with a prosthesis despite the larger energy expenditure needed to ambulate after a hip disarticulation compared to more distal amputations. Even without prosthetic use, most patients are very successful in ambulating and carrying out daily activities. Performing a hip disarticulation may be more preferable in some cases instead of leaving a patient with a very short above-knee amputation stump site, which can make prosthesis fitting difficult. Because functional outcome after hip disarticulation is problematic, Jain et al4 published their results of 80 hip disarticulations. Function on the whole was poor, with only one surviving patient regularly using an artificial limb. Patients after hip disarticulation are left without a leg and without a fulcrum to move an artificial limb. They are likely to suffer loss of self-esteem as well as loss of function and mobility, and they may well suffer from phantom pains. The energy expenditure during mobility after an amputation is much greater than that without an amputation and increases as the amputation level becomes more proximal.13 The energy expenditure after a hip disarticulation is reported to be 82% greater than that required by a nonamputee.2,3,10 In comparison, the energy expenditure after a long below-knee amputation is only about 10% more than that required by a nonamputee. When a patient with a hip disarticulation attempts to use a prosthesis, the energy requirements can then be as much as twice that of a normal ambulator. Those who cannot overcome these significant energy requirements must adapt to the use of crutches, canes, or a wheelchair. Given these factors, any intervention that can reduce the energy expenditures required of amputees might increase their likelihood of mobility and improve their overall quality of life.2,3,5,10 By preserving the soft tissues of the proximal thigh when amputating the leg at the level of the hip joint, it is possible to reconstruct a functional proximal thigh stump with a proximal femur prosthesis. This requires that the proximal soft tissues of the thigh are without tumor invasion, which is an uncommon situation. This is a rare procedure with only few indications, but it remains an important option due to its benefits over a standard hip disarticulation. Preserving hip function is the main advantage of stump prosthesis over hip disarticulation. The main disadvantages of a hip disarticulation are its unappealing appearance; the discomfort of the basket-shaped http://e-surg.com

prosthetic socket, which incorporates nearly half of the pelvis; and the 82% increase in energy consumption required for walking compared with that in a normal person.10 The stump prosthesis provides a lever arm for hip joint motion. This dramatically lowers the energy consumption of ambulating with a prosthetic limb and thus increases the likelihood of prosthetic use.9 The first attempt to improve the functional status of patients requiring hip disarticulation for malignant bone tumors was published in 1979.8

ANATOMY The hip joint region is supplied by several major arteries. Familiarity with these structures can minimize intraoperative bleeding if they can be identified and ligated as needed. These arteries include the profunda artery, the medial and lateral circumflex arteries, and the obturator and superior and inferior gluteal arteries. The tensor fascia lata, gluteus maximus, and iliotibial band form an outer muscular envelope around the hip, and at least one of these structures usually needs to be split to gain access to the hip. The femoral triangle must be identified to access the main neurovascular structures encountered in this procedure. The femoral triangle is bordered superiorly by the inguinal ligament, laterally by the sartorius muscle, and medially by the adductor longus muscle. Hip disarticulation involves amputation through the hip joint capsule. This strong fibrous layer covers the anterior hip to the intertrochanteric line but leaves most of the femoral neck exposed posteriorly. Tumors can often extend to the ischiorectal fossa; this should be determined preoperatively by examining computed tomography (CT) and magnetic resonance imaging (MRI) scans. The ischiorectal fossa is an area bounded medially by the sphincter ani externus and anal fascia, laterally by the tuberosity of the ischium and obturator fascia, anteriorly by the fascia covering the transversus perinei P.260 superficialis, and posteriorly by the gluteus maximus and sacrotuberous ligament. Assessment for tumor extension to this area is particularly important in planning the flaps that will be used.

INDICATIONS Proximal tumors not extending above the midthigh Femoral diaphyseal tumors with proximal intramedullary extension Soft tissue sarcomas of the thigh with extension to the femur or neurovascular structures Unresectable local recurrences, particularly after radiation therapy has been used Pathologic fractures that are not responsive to induction chemotherapy and immobilization Palliation of extensive tumors Indications for stump prosthesis reconstructive surgery after hip disarticulation are as follows (FIG 1): Skip metastasis to proximal femur from a primary distal femur osteosarcoma Inability to achieve safe osseous margins with a typical wide resection or above-knee amputation due to tumor extension (the most common indication)

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FIG 1 • Indications for hip disarticulation and reconstruction with a stump prosthesis. A. Proximal skip metastasis without soft tissue extension. B. Plain radiograph of a distal femoral nonunion after a pathologic fracture that was treated with a long retrograde intramedullary nail. C. Corresponding resected pathology gross specimen. D. Distal femoral synovial sarcoma with a proximal femoral head skip metastasis. Tumor contamination of the proximal medullary canal after pathologic fracture due to tumor in the distal femur and retrograde intramedullary fixation. A prerequisite for the operation is uncontaminated soft tissues around the hip, retrogluteal region, and proximal thigh.

IMAGING AND OTHER STAGING STUDIES Plain Radiography Hip and pelvic imaging to rule out pelvic involvement Radiographic analysis of the entire femur

Computed Tomography and Magnetic Resonance Imaging CT is useful in showing the effect of the tumor on the structural integrity of the bone. It may also show extension into the soft tissues, especially in the ischiorectal fossa, hip joint, and groin. http://e-surg.com

MRI shows the intraosseous spread of the tumor within the marrow and therefore is helpful in determining the level of amputation and the appropriateness of the hip disarticulation. P.261

Bone Scanning A bone scan is helpful in evaluating the bony involvement of the femur, pelvis, and acetabulum. It will also show any incidence of skip metastases. Acetabular involvement is a contraindication to doing a hip disarticulation.

Angiography and Other Studies Angiography can help identify the external iliac, common femoral, and profundus arteries when preparing for surgery.

Biopsy A biopsy is warranted before most amputations. Given the potential functional limitations and prosthetic needs of a hip disarticulation, a biopsy is definitely recommended before performing a hip disarticulation.

SURGICAL MANAGEMENT Lymph node involvement should be assessed before proceeding with a hip disarticulation. Lymph node involvement is a relative contraindication to performing a hip disarticulation unless the procedure is done for palliation. Hip disarticulations are often required after poor chemotherapy response or tumor aggressiveness. These situations increase the likelihood for close surgical margins, which can lead to local recurrences. All radiographic studies must be reviewed to ensure that there is no suggestion of tumor proximal to the lesser tuberosity. This would increase the risk of having positive or close margins. The development of the flaps is critical for optimal wound closure and healing. It is not uncommon to make flaps of unusual shape in performing a hip disarticulation for tumor of the middle or distal femur or thigh. Previous scars, radiated fields, and the presence of a tumor mass all determine the best skin to be used. If possible, fasciocutaneous flaps should be constructed to promote would healing. Optimizing the patient's overall health and nutritional status preoperatively is essential in promoting wound healing and decreasing perioperative complications. When planning for an amputation stump after disarticulation: Arterial blood supply to the soft tissues must be preserved. The superficial femoral artery should be ligated within the sartorial canal as distally as oncologically possible. The prosthesis must be secured to the hip capsule to avoid dislocation aggravated by gravity pulling on the prosthesis. This requires capsular reconstruction and reinforcement. Modular prosthetic design allows use of a large bipolar cup, modular body length with porous coating to aid in soft tissue ingrowth, and a distal rounded tip designed to avoid tissue penetration with distal muscle fixation holes (FIG 2). Muscle groups of the thigh must be connected distally to the prosthesis with tension balanced properly to avoid the excessively strong pull of the hip flexors and abductors. Sufficient soft tissue coverage of all the prosthesis, and specifically its distal part, is critical. http://e-surg.com

FIG 2 • A. The prosthesis body comes in different lengths. B. The distal tip is rounded to avoid penetration of tissues. Distal holes are used to anchor down the distal muscle ends. C. A modular stump prosthesis consists of a proximal bipolar head, porous coating, and holes to reconnect the hip capsule and abductor mechanism. Phantom pain and stump pain should be addressed initially by placing an epineural catheter in the transected sciatic nerve and using multimodal analgesia.

Preoperative Planning MRI and CT are done to determine the extent of the tumor in the proximal femur. Manipulation of more proximal venous structures can increase the likelihood of the development of deep venous thrombi. Often, these more proximal thrombi can embolize and lead to fatal pulmonary emboli. In patients with a prior history of deep venous thrombosis or pulmonary emboli, the surgeon should consider placing a venous filter before surgery to minimize the risk of pulmonary emboli. An amputation is a life-altering event; both physical and emotional issues need to be addressed. Many patients find psychological counseling helpful, so the surgeon should ensure that these services are available in the http://e-surg.com

perioperative period. Having patients meet with a prosthetist and a functional amputee can help manage expectations and provide answers about daily activities and function. If an amputation stump is to be used, a custom bullet-tip prosthetic extension should be ordered.

Positioning Because a hip disarticulation involves both anterior and posterior dissections, a semilateral or lateral position is often best. Some surgeons prefer the patient to be in more of a supine position if an amputation stump is to be created. P.262

Approach The major portions of the hip disarticulation are done through an anterior approach to the hip and groin. This facilitates exposure of the femoral triangle and muscle origins and allows for anterior flap development.12 Recently, Lackman et al7 published their technique using the lateral approach for hip disarticulations. This has the advantage of familiarity and provides access to both anterior and posterior structures.

TECHNIQUES ▪ Incision and Initial Exposure Bony landmarks to be identified include the pubic tubercle, anterior superior iliac spine, anterior inferior iliac spine, ischial tuberosity, and greater trochanter (TECH FIG 1A). The anterior incision starts 1 cm medial to the anterior superior iliac spine and continues distally to the pubic tubercle and over to the pubic bone to 2 cm distal to the ischial tuberosity and gluteal crease. If the buttock flap is extremely thick, the anterior portion of the incision should be moved laterally. The posterior incision starts about 2 cm anterior to the greater trochanter and extends to the back of the leg distal to the gluteal crease. The distance of the incision beyond the gluteal crease is directly proportional to the anteroposterior diameter of the patient's pelvis. Skin, subcutaneous fat, and fascia of Scarpa are incised to expose the aponeurosis of the external oblique. Saphenous vein branches are clamped, divided, and ligated.

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TECH FIG 1 • A. Incision. B. Exposure of the femoral triangle. C. Division of the femoral vessels and nerve. A moderate-sized artery, the superficial epigastric, and multiple branches of the external pudendal vessels are secured. The spermatic cord in men or the round ligament in women is identified, and care is taken to avoid injuring these structures. An incision made just below the inguinal ligament into the fossa ovalis exposes the femoral vein, artery, and nerve (TECH FIG 1B). Individual silk ties are placed around the femoral vessels; first the artery and then the vein are tied in continuity. Right angle clamps are placed between the ties, and the vessels are severed. The proximal ends of the vessels are further secured by a silk suture ligature placed proximal to the right angle clamps. The femoral nerve is placed on gentle traction and ligated where it exits from beneath the inguinal ligament. When the femoral nerve is severed, it retracts beneath the external oblique aponeurosis, so that if a neuroma forms, it will not be in a weightbearing portion of the stump (TECH FIG 1C). P.263

▪ Division of Anterior Hip and Groin Muscles and Ischial Tuberosity Release The sartorius muscle is located as it arises from the anterior superior iliac spine. It is dissected free from the surrounding fascia and then transected from its origin on the spine by electrocautery. The femoral sheath and fibroareolar tissue posterior to the femoral vessels are also incised by electrocautery. This dissection exposes the hip joint capsule (TECH FIG 2A). With the hip slightly flexed, a finger can be placed in a mediolateral direction under the iliopsoas to isolate http://e-surg.com

the muscle, which can then be freed from its origin at the lesser trochanter (TECH FIG 2B). If an attempt is made to pass the finger beneath the muscle from lateral to medial, the very intimate attachments between the iliopsoas muscle and the rectus femoris muscle prevent this from being easily done. By sharp and blunt dissection, the entire iliopsoas muscle is dissected until its insertion on the lesser trochanter is clearly defined. Several vessels of prominent size pass from the anterior surface of this muscle, and care should be taken to secure these vessels before their division. The iliopsoas muscle is severed at the level of its insertion onto the lesser trochanter.

TECH FIG 2 • A. Division of the sartorius muscle and femoral sheath. B. Division of iliopsoas muscle at its insertion. The hip is flexed slightly to relax the iliopsoas muscle. C. Transection of pectineus muscle at its origin. D. Transection of the gracilis, adductor longus, brevis, and magnus muscles from their origin; division of the obturator vessels and nerve. E. Release of the flexor muscles from the ischial tuberosity. Next, the adductor muscles are released from the pelvis in a lateral to medial process. To preserve the obturator externus muscle on the pelvis, the surgeon locates its prominent tendon arising from the lesser trochanter. P.264 http://e-surg.com

Locating this tendon identifies the plane between the pectineus muscle and the obturator externus; a difference in the direction of the muscle fibers of these two muscles is also apparent. A finger is passed beneath the pectineus muscle, and it is released at the level of its origin from the pubis by electrocautery (TECH FIG 2C). Beneath the pectineus muscle, numerous branches of the obturator artery, vein, and nerve can now be visualized. The gracilis, adductor longus, adductor brevis, and adductor magnus are transected at their origins on the symphysis pubis. The obturator vessels and nerves usually bifurcate around the adductor brevis muscle. Branches of the obturator artery must be identified and secured during the dissection to prevent accidental rupture and retraction of the proximal ends up into the pelvis (TECH FIG 2D). The extremity is hyperabducted to localize the ischial tuberosity and the retracted cut ends of the abductor muscles. The circumflex femoral vessels should be visible and should be avoided. The semimembranosus, semitendinosus, and long head of the biceps are transected from their origin on the ischial tuberosity while preserving the quadratus femoris and sciatic nerve (TECH FIG 2E).

▪ Hip Joint Capsule Incision and Division of Posterior Muscles All the anterior and posterior muscle groups have been divided. The joint capsule overlying the head of the femur is incised, and the ligamentum teres is transected by electrocautery (TECH FIG 3A). The patient's torso is tilted from posterolateral to anterolateral. The incision is completed posteriorly through gluteal fascia (TECH FIG 3B). The tensor fascia lata and gluteus maximus muscles are divided in the depths of the skin incision. These are the only muscles not divided at either their origin or insertion in the procedure. Directly beneath these muscles is the rectus femoris muscle, which is transected at its origin on the anterior inferior iliac spine by electrocautery (TECH FIG 3C). The common tendon comprising contributions from the gluteus medius, gluteus minimus, piriformis, superior gemellus, obturator internus, inferior gemellus, and quadratus femoris muscles is exposed after the division of the gluteus maximus. All these muscles are divided close to their insertions on the greater trochanter (TECH FIG 3D).

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TECH FIG 3 • A. Incision of the anterior portion of the hip joint capsule. B. Completion of the skin incision. C. Division of the tensor fascia lata, gluteus maximus, and rectus femoris muscles. (continued) P.265

TECH FIG 3 • (continued) D. Transection of the muscles inserting into the greater trochanter. E. Release http://e-surg.com

of specimen. F. Approximation of the obturator externus and gluteus medius over the joint capsule. Transection of the hip joint capsule is completed by incising the posterior portion of the capsule. The sciatic nerve is dissected free of surrounding muscle, transected, and allowed to retract beneath the piriformis muscle (TECH FIG 3E). The obturator externus and gluteus medius are sutured together over the acetabulum and joint capsule to help provide soft tissue coverage of the bony prominence (TECH FIG 3F). Creating a Femoral Stump with a Proximal Femoral Modular Prosthesis The proximal femoral modular prosthesis comprises a proximal bipolar part, a body, and a distal rounded tip. The proximal bipolar part has holes and porous coating around the base of the neck that is intended for reattaching the hip capsule and the greater trochanter. This prevents sliding of the transferred muscles. The prosthesis body has variable length options. The correct length is chosen according to trial measurements. The distal conical tip is custom-made to fit the prosthetic body. It has a rounded bullet-shaped tip to avoid penetrating the soft tissue and includes two sets of four holes each for reattaching the distal ends of the quadriceps, hamstrings, and adductor muscles. A trial proximal femoral prosthesis can be assembled based on an approximation of the required length. The resected femoral head should be measured to help approximate the head cup size that is required. The trial prosthesis should be placed into the acetabulum and the soft tissues should be released from their retracted positions to simulate closure and demonstrate whether the trial prosthesis will allow adequate soft tissue closure (TECH FIG 4). Once the desired prosthesis is determined, the prosthesis is assembled and the Morse tapers are impacted. Reconstruction of the Hip Joint Capsule To strengthen the capsular closure, we use 3-mm Dacron tape, which acts as a noose around the prosthesis to prevent dislocation. This step is often easier if done just before the actual prosthesis placement.

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TECH FIG 4 • Trial measurements of the stump prosthesis. Bipolar cup size may be adjusted to fit the acetabular diameter. Body length is measured so that when muscle groups (quadriceps, hamstrings, and adductors) are reconnected distally, even tension and a neutral position of the limb are achieved. P.266

TECH FIG 5 • A,B. The hip capsule that had been tagged at the time of resection is reconstructed and attached to the proximal part of the prosthesis. The psoas muscle is reattached on the anterior aspect of the capsule and the external rotators are reattached to the posterior capsule. The Dacron tape is sewn circumferentially around the cut capsule (TECH FIG 5). Putting too much tension on the Dacron tape may cause difficulty in reducing the prosthesis. Once the Dacron is in place, the assembled prosthesis is reduced into the acetabulum and the Dacron is snugly tightened and tied, forming a noose around the femoral neck. In our experience, this has helped to prevent dislocations. The hip joint should be put through functional range of motion to ensure a successful outcome. Once the surgeon is satisfied with the prosthesis and range of motion, the previously detached iliopsoas muscle is pulled over the anterior hip capsule and sutured to it with Ethibond. The short external hip rotators are pulled anteriorly and sutured to the posterior capsule. http://e-surg.com

TECH FIG 6 • A-C. The abductors and greater trochanter are reattached with a cable system. The adductors are reconnected to the prosthesis body. Reconstruction of the Adductor and Abductor Mechanism The hip abductors with the osteotomized greater trochanter are repositioned and reconnected with cables and a greater trochanter grip (TECH FIG 6A). The adductors are reconnected to the stump stem (TECH FIG 6B,C). P.267 The remaining proximal portion of the sciatic nerve is identified. Its epineural sheath is opened carefully using a fine right angle clamp, and a standard epidural catheter is placed and threaded proximally for at least 5 to 10 cm within the sheath. The catheter is then sutured to nearby adipose or muscular tissue to help secure it using a 4-0 chromic suture. A 14-gauge angiocatheter is placed at the desired exit point for the catheter, with the needle passing beneath the subcutaneous and muscular layers. The epineural catheter is threaded through the angiocatheter to its desired position at the skin level and the angiocatheter is removed with the epineural catheter now outside the skin. The catheter should be infused with 4 to 8 mL 0.25% bupivacaine without epinephrine to aid in postoperative pain control. Soft Tissue Reconstruction and Wound Closure Dacron tapes are sutured into all cut distal stumps of the quadriceps, adductors, and hamstrings (TECH FIG 7).

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TECH FIG 7 • The distal muscle ends are tagged at the time of resection. Reconstruction consists of balancing between flexor and extensor muscles and between the abductors and the adductors. These are all reconnected to the distal end of the prosthesis and to each other. Technically, this is done with the prosthesis in neutral position. A,B. The quadriceps, hamstrings, and adductor muscle groups are pulled and attached to the prosthesis with even tension. The muscle ends are then connected to one another at their distal ends. C,D. When connected correctly, the prosthesis remains in neutral position as the patient awakens on the operating table. The posterior muscle groups are tenodesed to the stump prosthesis using the holes made into the distal portion of the prosthesis with the hip in complete extension. The quadriceps muscle is tenodesed to the anterior portion of the stump prosthesis in a similar fashion through the preformed holes, also with the hip in extension. The adductor group is connected in a similar fashion. By setting the prosthesis in neutral position and pulling all three groups and tenodesing them at once, muscle balance is achieved. The surgeon should avoid hip flexion and adduction. The ends of the muscles are sutured to each other, forming a continuous fascial border covering the distal stump. Appropriate muscle tensioning and balancing are imperative to prevent muscle contractures, particularly abduction and adduction or flexion contractures. The reconstructed stump should lie in neutral position. The origin of the vastus lateralis is reattached to the greater trochanter proximally. The vastus lateralis fascia is tenodesed to the fascia lata. P.268

▪ Release of Specimen and Closure if a Stump Is Not Created The gluteal fascia is elevated and secured to the inguinal ligament and the pubic ramus. Multiple stitches are placed bisecting the fascial edge that gather the gluteal fascia as it is secured to the inguinal ligament. http://e-surg.com

Sutures are individually placed and then tied. Before closure of this posterior myocutaneous flap, suction catheters are placed beneath the gluteal fascia. The skin is closed with interrupted sutures. Again, care is taken to make sure that there is equal distribution of the excess tissue of the posterior flap. Not infrequently, additional suction catheters must be used to obliterate space within the subcutaneous tissue when the buttock flap is thick (TECH FIG 8). Patency of the suction catheters must be maintained until drainage is diminished. Ambulation may proceed if the patient's hemodynamic status permits on the first postoperative day.

TECH FIG 8 • Skin closure and drainage catheters.

PEARLS AND PITFALLS Sparing the abductor mechanism with a greater trochanter osteotomy

▪ As long as no disease involves the area of the greater trochanter, this should be osteotomized and used in reconnecting the abductor mechanism.

Trial prosthesis

▪ Measurements should be made intraoperatively for the bipolar head size and body length of the prosthesis.

Hip capsule

▪ Hip joint capsule should be preserved and tagged. After resection, the capsule should be reconnected to the prosthesis around the base of the neck. The hip capsule is then reinforced by connecting the distal end of the psoas muscle to the anterior capsule and the short external rotators to the posterior capsule.

Muscle tension

▪ The quadriceps, hamstrings, and adductor muscles should be reconnected at equal tension while the prosthesis is in neutral position.

Bony prominences

▪ Closure of the remaining obturator externus to the gluteus medius provides good soft tissue coverage over bony prominences, which facilitates prosthetic use.

Wounds and incisional areas

▪ The remaining flap tissue should be distributed equally and carefully to eliminate irritated redundant tissue, which could cause asymmetry of the incisional area and discomfort with prosthetic use or problems with prosthesis use.

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Dead space closure

▪ Approximating the remaining iliopsoas and quadratus femoris provides good soft tissue closure over the joint capsule and closes some of the dead space created by the amputation.

Phantom pain

▪ Postoperative analgesia is crucial. We believe pain should be treated perioperatively by inserting an epineural catheter into the transected tip of the sciatic nerve. ▪ The use of epineural catheters in the remnants of the femoral and sciatic nerves decreases the incidence and severity of phantom pain and sensations and can decrease overall narcotic needs.

POSTOPERATIVE CARE A compressive dressing should be maintained for 3 to 5 days to minimize swelling. After this time, the wound should be inspected and redressed. Drains should remain until the total daily output is minimal, usually about 3 to 4 days following surgery. Compressive dressings are used for the first few weeks after surgery. A prosthesis may be fitted as soon as the wound has healed. Full weight bearing is permitted. Physiotherapy may begin promptly after surgery and should focus on achieving good range of motion. Prosthesis fitting can begin when the wound swelling has decreased and the wound is completely healed. Usually, this takes at least 4 to 6 weeks after surgery.

OUTCOMES The 5-year survival of patients after hip disarticulation done as the primary treatment is 32%. When done for local recurrence, the 5-year survival is 25%. Hip disarticulation has been shown to be very effective as a means of palliation for extensive tumors without other treatment options. It thus improves the quality of life of these patients. The senior authors have used the technique of creating an above-knee amputation stump after hip disarticulation in six patients—osteosarcoma (n = 2), malignant fibrous histiocytoma (n = 2), and synovial sarcoma (n = 2)—with very good results. There were no infections, dislocations, and local recurrences nor were secondary procedures required in any of those patients. P.269

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FIG 3 • Patient after hip disarticulation and proximal thigh stump reconstruction after being fitted with an above-knee prosthesis. Prosthetic use in this population is usually lower than that seen in groups with more distal amputations. Use ranges from 5% to 60% of amputees. Problems with artificial limb use and reasons for the lack of limb use have included limb weight and inconvenience with toileting. Despite this, all patients should be offered an artificial limb. Many patients with hip disarticulations are very functional (FIG 3), and one study found that most were even able to drive whether or not they used a prosthesis.

COMPLICATIONS The local recurrence rate is 2% to 12% and is usually higher in patients whose amputation was done for local recurrences or if there were close margins. A possible complication is deep infection involving the prosthesis. Stump reconstruction should be http://e-surg.com

undertaken only when it is evident that there is no infection of the limb. If there is any doubt about infection, a two-stage procedure is recommended. To avoid hip dislocation when an amputation stump is created, the hip joint capsule must be reconstructed. The reconstructed hip is then reinforced with the psoas anteriorly and the short external rotators posteriorly. Stability should be assessed intraoperatively. There is a natural tendency for the stump to migrate toward flexion and abduction due to the muscle strength of the quadriceps and abductors. It is therefore crucial to achieve muscle balance of the quadriceps, adductors, hamstrings, and abductors during reconstruction. Wound healing problems can arise from seroma or hematoma development. The use of drains can help decrease the risk of seromas and hematomas.

REFERENCES 1. Abudu A, Sferopoulos NK, Tillman RM, et al. The surgical treatment and outcome of pathological fractures in localised osteosarcoma. J Bone Joint Surg Br 1996;78B:694-698. 2. Chin T, Kuroda R, Akisue T, et al. Energy consumption during prosthetic walking and physical fitness in older hip disarticulation amputees. J Rehabil Res Dev 2012;49(8):1255-1260. 3. Dillingham TR, Pezzin LE, MacKenzie EJ. Limb amputation and limb deficiency: epidemiology and recent trends in the United States. South Med J 2002;95:875-883. 4. Jain R, Grimer RJ, Carter SR, et al. Outcome after disarticulation of the hip for sarcomas. Eur J Surg Oncol 2005;31:1025-1028. 5. Jeans KA, Browne RH, Karol LA. Effect of amputation level on energy expenditure during overground walking by children with an amputation. J Bone Joint Surg Am 2011;93(1):49-56. 6. Kalson NS, Gikas PD, Aston W, et al. Custom-made endoprostheses for the femoral amputation stump: an alternative to hip disarticulation in tumour surgery. J Bone Joint Surgery Br 2010;92(8): 1134-1137. 7. Lackman RD, Quartararo LG, Farrell ED, et al. Hip disarticulation using the lateral approach: a new technique. Clin Orthop Relat Res 2001;392:372-376. 8. Marcove RC, McMillian RD, Nasr E. Preservation of the functional above-knee stump following hip disarticulation by means of an Austin-Moore prosthesis. Clin Orthop Relat Res 1979;141: 217-222. 9. Merimsky O, Kollender Y, Inbar M, et al. Palliative major amputation and quality of life in cancer patients. Acta Oncol 1997;36: 151-157. 10. Nowroozi F, Salvanelli ML, Gerber LH. Energy expenditure in hip disarticulation and hemipelvectomy amputees. Arch Phys Med Rehabil 1983;64:300-303. 11. Rougraff BT, Simon MA, Kneisl JS, et al. Limb salvage compared with amputation for osteosarcoma of the distal end of the femur: a longterm oncological, functional, and quality-of-life study. J Bone Joint Surg Am http://e-surg.com

1994;76A:649-656. 12. Sugarbaker P, Malawer M. Hip disarticulation. In: Malawer MM, Sugarbaker PH. Musculoskeletal Cancer Surgery: Treatment of Sarcomas and Allied Diseases. Boston: Kluwer, 2001:337-349. 13. Van der Windt DA, Pieterson I, van der Eijken JW, et al. Energy expenditure during walking in subjects with tibial rotationplasty, aboveknee amputation, or hip disarticulation. Arch Phys Med Rehabil 1992;73:1174-1180. 14. Westbury G. Hindquarter and hip amputation. Ann R Coll Surg Engl 1967;40:226-234.

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Chapter 24 Proximal and Total Femur Resection with Endoprosthetic Reconstruction Jacob Bickels Martin Malawer

BACKGROUND The proximal and midfemur are common sites for primary bone sarcomas and metastatic tumors. Patients who were candidates for extensive femoral resection because of malignant tumor had long been considered a high-risk group for limb-sparing procedures because of the extent of bone and soft tissue resections, the anticipated poor function postoperatively as well as the deleterious consequences of adjuvant chemotherapy and radiation therapy. Hip disarticulation or hemipelvectomy were, therefore, the classic treatment options for patients with large lesions of the proximal or midfemur. Both procedures were associated with a dismal functional, aesthetic, and psychological outcome. Today, improved survival of patients with musculoskeletal malignancies, developments in bioengineering, and refinements in surgical technique have enabled the performance of limb-sparing procedures for these patients as well. Local tumor control is good, as is the probability of a functional extremity. Proximal and total femur resection became a reliable surgical option in the treatment of primary bone sarcomas and metastatic bone disease and, more recently, of a variety of nononcologic indications. These latter indications include failure of internal fixation, severe acute fractures with poor bone quality, failed total hip arthroplasty, chronic osteomyelitis, metabolic bone disease, and various congenital skeletal defects.1,4 Methods of skeletal reconstruction include resection arthrodesis, massive osteoarticular allograft, endoprosthetic reconstruction, and prosthetic allograft composites.2,3,5,7 Osteoarticular allografts, which were popular in the 1970s and 1980s, aim to restore the natural anatomy of a joint by matching the donor bone to the recipient's anatomy, but they are associated with increased rates of infection, nonunion, instability, fracture, and subchondral collapse and thus ultimate failure.6,8 Introduced in the mid-1980s, modular prostheses revolutionized endoprosthetic reconstruction. The modular system enables the surgeon to measure the actual bone defect at the time of surgery and select the most appropriate components to use in reconstruction. Components of these interchangeable systems include articulating segments, bodies, and stems of varying lengths and diameters. Design features include extensive porous coating on the extracortical portion of the prostheses for bone and soft tissue fixation and metallic loops to assist in muscle reattachment (FIG 1). Prosthetic reconstruction of the proximal and total femur has been shown to be associated with good function and minimal morbidity in the majority of the patients.1 Preservation of the joint capsule and reattachment of the abductor mechanism have also been shown to considerably decrease the rate of dislocations, which have traditionally been the most common complication of endoprosthetic reconstruction at that site.1

ANATOMY Hip joint and joint capsule. The intracapsular location of the femoral neck makes it biologically possible for tumors of the proximal femur to spread into the hip and adjacent synovium, joint capsule, and ligamentum http://e-surg.com

teres. The ligamentum teres provides a mechanism for transarticular skip metastases to the acetabulum. Fortunately, intra-articular involvement is rare and usually occurs after a pathologic fracture. The capsule can be preserved and an intra- articular resection of the femur is usually possible. In the case of capsular or acetabular involvement or both, extra-articular resection of the hip should be considered. The greater trochanter, which is removed with the surgical specimen, serves as the attachment site for the hip abductors. The tendon stump should be marked and preserved for reattachment to the prosthesis. The lesser trochanter, which is removed with the surgical specimen, serves as the attachment site for the psoas muscle. The tendon stump should be marked and preserved for reattachment to the prosthesis. The combined attachment of the abductors and psoas to the lateral and medial aspects of the prosthesis, respectively, preserves balanced prosthetic range of motion (FIG 2). The femoral artery descends the thigh almost vertically within the sartorial canal toward the adductor tubercle of the femur, enters the opening of Hunter canal at the adductor magnus muscle and becomes the popliteal artery. The profunda femoris artery branches to the medial aspect of the femoral artery 4 cm below the inguinal ligament. Occasionally, the profunda femoris is ligated and resected en bloc with large tumors of the proximal femur. Ligation of the profunda femoris in an adolescent patient with patent vasculature of the lower extremity is not expected to result in vascular compromise. However, preoperative angiography is strongly recommended in adults because ligation of the profunda femoris in the presence of an occluded superficial femoral artery may result in an ischemic extremity and the subsequent need for amputation. P.271

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FIG 1 • A-D. Modular proximal and total femoral prostheses. Components of these interchangeable systems include articulating segments, bodies, and stems of varying lengths and diameters. Design features include porous coating for bone and soft tissue fixation and metallic loops to assist in the reattachment of the abductor mechanism. E,F. Modular prosthetic components are used to reconstruct a proximal femoral defect that had been created after resection of a metastatic lesion.

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FIG 2 • Combined attachment of the abductors and psoas to the medial and lateral aspects of the prosthesis, respectively, preserves balanced prosthetic range of motion. The knee joint is seldom directly invaded by tumors of the femur that extend to its distal aspect. When it does occur, invasion is usually the result of a pathologic fracture, contamination of an improper biopsy technique, or tumor extension along the cruciate ligaments. The presence of hemarthrosis is suggestive of intra-articular disease, and intra-articular resection of the knee joint (ie, en bloc resection of the femur with the knee joint capsule and articular surface of the proximal tibia) should be considered in those cases.

INDICATIONS Primary bone sarcomas (FIG 3) Benign aggressive tumors associated with extensive bone destruction (FIG 4) Metastatic tumors associated with extensive bone destruction (FIG 5) Nononcologic indications which include failure of internal fixation, severe acute fractures with poor bone http://e-surg.com

quality, failed total hip arthroplasty with segmental bone loss below the level of the lesser trochanter, chronic osteomyelitis, P.272 metabolic bone disease, and various congenital skeletal defects (FIG 6)

FIG 3 • Osteosarcoma (A) and chondrosarcoma (B) of the proximal femur. Sections through an osteosarcoma (C) and high-grade chondrosarcoma (D) of the proximal femur showing tumor extension throughout the medullary canal. A wide resection of these tumors necessitates removal of the proximal femur. Proximal femur resection is performed for metaphyseal-diaphyseal lesions that (1) extend below the lesser trochanter, (2) cause extensive cortical destruction, and (3) spare at least 3 cm of the distal femoral diaphysis. Total femur resection is performed for diaphyseal lesions that (1) extend proximally to the lesser trochanter and distally to the distal diaphyseal-metaphyseal junction and (2) cause extensive bone destruction (FIG 7).

IMAGING AND OTHER STAGING STUDIES Proximal and total femur resections are major surgical procedures that necessitate an especially detailed preoperative evaluation. Physical examination and imaging studies are supposed to determine the following: Extent of bone resection and dimensions of the required prosthesis Extent of soft tissue resection and reconstruction possibilities Proximity of the tumor to the femoral vessels, femoral nerve, and sciatic nerve Most complications can be avoided by predicting their likelihood prior to surgery and modifying the surgical technique accordingly. A full range of imaging studies is needed, including plain radiography, computed tomography (CT), and magnetic resonance (MR) imaging of the whole femur and the hip and knee joints. CT and plain radiography are used to evaluate the extent and level of bone destruction, and MR imaging is used to evaluate the medullary and extraosseous components of the tumor, intracapsular tumor extension, and the presence of skip metastases within the femoral canal and in the acetabulum.

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FIG 4 • Giant cell tumor of the proximal femur with a pathologic hip fracture. Angiography of the iliofemoral vessels is essential prior to resection of tumors of the proximal femur. Vascular displacement is common when tumors have a large, medial extraosseous component: The profundus femoral artery is particularly vulnerable to distortion or, less commonly, to direct incorporation into the tumor mass. If the tumor has a large medial extraosseous component and ligation of the profundus femoral artery is anticipated, the presence of a patent superficial femoral artery must be documented by angiography prior to surgery. Preoperative embolization may be useful in preparation for resection of metastatic vascular carcinomas if an intralesional procedure is anticipated. Metastatic hypernephroma is an extreme example of a vascular lesion that may bleed extensively and cause exsanguination upon the execution of an intralesional procedure without prior embolization.

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FIG 5 • Metastatic carcinoma of the proximal femur with a pathologic subtrochanteric fracture. P.273

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FIG 6 • Chronic and neglected osteomyelitis of the proximal femur associated with a nonunion of an insufficiency fracture, debilitating pain, and loss of function. Performance of a proximal femur resection with endoprosthetic reconstruction resulted in complete resolution of pain and considerable functional improvement.

SURGICAL MANAGEMENT Limb-sparing surgery that involves endoprosthetic replacement of the proximal or the entire femur is done in three steps: tumor resection, endoprosthetic reconstruction, and soft tissue reconstruction. The technique of proximal femur endoprosthetic replacement is described in the following paragraphs. The additional steps required for total femur resection are described at the end of the appropriate sections. In general, surgery for metastatic tumors to the proximal femur is not different from surgery for primary sarcomas of bone. The main differences are that metastatic lesions have a smaller extraosseous component than primary lesions, and the surrounding muscles are usually invaded by the meta-static lesions (as opposed to the “pushing” border of bone sarcomas). http://e-surg.com

FIG 7 • Section through a large osteosarcoma of the femur, the medial periosteal reaction of which extended beyond the lesser trochanter, thus necessitating total femur resection for its removal.

TECHNIQUES ▪ Tumor Resection Position and Incision The patient is placed in a lateral position and a long lateral incision is made extending from 3 to 4 cm proximal to the greater trochanter to the distal two-thirds of the thigh (TECH FIG 1A,B). An ilioinguinal extension to that incision is added if the tumor has an extensive, medial soft tissue component along the proximal femur. This approach allows exposure of the proximal one-third of the femur and the retrogluteal area and allows for identification of the femoral canal, femoral triangle, superficial and profundus femoral artery, and sartorial canal. Posterior reflection of the gluteus maximus muscle exposes the retrogluteal area, external rotators, sciatic http://e-surg.com

nerve, abductors, and posterior capsule. If total femur resection is performed, the incision is brought distally to the anterolateral aspect of the patellar tendon and tibial tuberosity. If the tumor has a medial component along the distal femur, it is best approached through a medially curved incision (TECH FIG 1A,C,D). Gluteus Medius and Maximus Detachment The iliotibial band is opened longitudinally to allow adequate anterior and posterior exposure and partial detachment of the femoral insertion of the gluteus maximus muscle. Posterior reflection of the gluteus maximus muscle allows ligation of the first perforating artery, which is in intimate apposition with the gluteal tendon attachment. The gluteus maximus is then further retracted in a posterior direction, exposing the retrogluteal area, external rotators, sciatic nerve, abductors, and posterior capsule (TECH FIG 2). The sciatic nerve lies directly posterior to the external rotators. In general, as primary bone sarcomas expand, the external rotators are pushed outward and act as a protective barrier to the sciatic nerve. As such, the sciatic nerve is often not in its usual anatomic location in these patients and must be identified early, isolated, and mobilized posteriorly in order to prevent injury. The abductors are identified with their anterior and posterior intervals. If there is no tumor involvement, the greater trochanter or small bony attachment is osteotomized; otherwise, the P.274 P.275 abductors are transected through their tendinous attachments and retracted, exposing the hip joint and acetabulum.

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TECH FIG 1 • Illustration (A) and operative photograph (B) showing a long lateral incision used for resection of the proximal or the whole femur. C,D. The incision is brought distally to the anterolateral aspect of the patellar tendon and tibial tuberosity for exposure of the entire femur. If the tumor has medial or posterior soft tissue extensions at the distal femur which require dissection at the medial aspects of the knee and popliteal fossa, the incision is curved medially at its distal part.

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TECH FIG 2 • Illustration (A) and operative photograph (B) showing the proximal femur after posterior retraction of the gluteus maximus and exposure of the retrogluteal area, external rotators, sciatic nerve, abductors, and posterior capsule. Because of tumor extension into the greater trochanter in the illustrated case, the abductors are identified and transected through their tendinous attachments and retracted, exposing the hip joint and acetabulum. If the greater trochanter is not involved by tumor extension, it is osteotomized and reflected with the abductor tendon.

TECH FIG 3 • Illustration (A) and operative photograph (B) showing transected distal reflection of the vastus lateralis from its origin at the vastus ridge. Vastus Lateralis Reflection The vastus lateralis is transected from its origin at the vastus ridge and reflected distally, and the posterior perforating vessels are ligated (TECH FIG 3). The vastus lateralis must be preserved because of its future role in soft tissue coverage of the prosthesis: It will be advanced proximally and sutured to the abductors (see section on Soft Tissue Reconstruction). Care is taken not to ligate its main pedicle, which http://e-surg.com

crosses anteriorly and obliquely along the rectus femoris fascia. The femoral nerve is identified below the fascia (see TECH FIG 3). The superficial and profundus femoral artery and vein are identified in the sartorial canal and retracted. If they are invaded by the soft tissue extension of the tumor, the profundus artery and vein may be ligated just distal to their takeoff from the common femoral vessel. Detachment of Posterior Hip Musculature and Capsule, Dislocation of Femur With the retrogluteal area having been exposed, the rotator muscles are now detached en bloc 1 cm from their insertion on the proximal femur. The hip joint capsule has a major role in securing and stabilizing the head of the prosthesis within the acetabulum and, if not invaded by tumor, it should remain intact. The capsule is opened longitudinally along its anterolateral aspect and detached circumferentially from the femoral neck. The femur is dislocated anterolaterally. Special care is taken not to fracture the femoral neck, especially if a primary bone sarcoma is being resected. The acetabulum is inspected for evidence of joint involvement (TECH FIG 4A,B). If total femur resection is performed through an anterolateral knee arthrotomy, the cruciate ligaments, collateral ligaments, and menisci are resected, as are the capsular and muscular attachments to the distal femur (TECH FIG 4C,D). If delicate dissection around the popliteal vessels is anticipated, an anteromedial arthrotomy should be done and the popliteal fossa should be approached from its medial aspect. The total femur is resected en bloc with the vastus intermedius muscle, whereas the vastus lateralis, rectus femoris, patella, and patellar tendon are preserved. Because malignant tumors of the distal femur rarely penetrate beyond the vastus intermedius muscle or patellar surface, the patella can be preserved in the large majority of the cases.

TECH FIG 4 • Illustration (A) and operative photograph (B) showing detachment of the posterior hip musculature and capsule. (continued) P.276

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TECH FIG 4 • (continued) Illustration (C) and operative photograph (D) showing the arthrotomy of the knee joint that is required to accomplish total femur resection. An anterolateral arthrotomy using the initial lateral incision is usually feasible. However, in cases where tumor extends toward the popliteal fossa and delicate dissection of the popliteal vessels is anticipated, anteromedial knee and medial exposure of the popliteal fossa are done as for resection of the distal femur. The femur will be removed with the overlying vastus intermedius, whereas the rectus femoris and patella are spared. Distal Femoral Osteotomy and Release of Medial Structures Femoral osteotomy is performed at the appropriate location, as determined by the preoperative imaging studies. In general, 3 to 4 cm beyond the farthest point is appropriate for primary sarcomas and 1 to 2 cm for metastatic carcinomas. An oscillating saw is used for the osteotomy and a malleable retractor is placed medially to the femoral shaft to prevent inadvertent injury to the soft tissues. The cut should be at a right angle to the shaft (TECH FIG 5).

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TECH FIG 5 • Illustration (A) and operative photographs (B-D) showing distal femur osteotomy and removal of the proximal femur. The femoral osteotomy is done 3 to 4 cm beyond the farthest point of tumor extension for primary sarcomas and 1 to 2 cm for metastatic carcinomas. P.277 It is important not to distract the extremity following removal of the proximal femur in order to avoid placing tension on the sciatic nerve and femoral vessels. If total femur resection is performed, a tibial osteotomy is carried out in the same manner as a standard knee joint arthroplasty in which approximately 1 cm of bone is removed, the cut is perpendicular to the long axis of the tibia, and the insertion of the biceps femoris muscle is retained. Following femoral osteotomy or disconnection of the entire femur after tibial osteotomy, the femur is retracted laterally. The remaining medial structures are now clearly visible: They consist of the psoas and adductor muscles, which should be identified either now or at some point before the femur is osteotomized. The muscles are serially dissected, clamped with Kelly clamps, and tagged with Dacron tapes (Deknatel, Falls River, MA). Care is taken to dissect the profundus femoral artery. If oncologically indicated, the profundus femoral artery may be ligated but only after patency of the superficial femoral artery has been confirmed.

▪ Endoprosthetic Reconstruction Following resection of the proximal femur, the length of the resected specimen, the size of the femoral head, and the diameter of the distal medullary canal are measured. A trial femoral head prosthesis is used to test the suction fit. The proximal end of the remaining femur should be kept well padded in order to avoid injuring the superficial femoral artery. A frozen section from the canal is evaluated for evidence of residual tumor before reaming the femoral canal. Reaming the Intramedullary Canal The largest possible stem diameter should be chosen, especially for primary tumors. A 1-mm cement mantle is required around the stem. The intramedullary canal is therefore reamed 2 mm larger than the chosen stem diameter (TECH FIG 6). Trial Articulation Modular trial prosthetic components should be assembled to match the length of the resected specimen. These include body parts, a neck, and prosthetic head (TECH FIG 7A-C). Total femur prostheses are joined to the tibial component via a rotating hinge mechanism (TECH FIG 7D,E).

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TECH FIG 6 • Illustration showing reaming of the medullary canal. Following trial positioning of the prosthesis, the pulses are palpated distally: A shorter prosthesis will be required if they are diminished. The joint capsule is pulled over the femoral head component, and the range of motion of the hip joint is tested. The prosthesis should be stable in flexion, adduction, and internal rotation. Prosthetic Assembly and Implantation The modular prosthesis is assembled and cemented into the medullary canal. The orientation of the prosthesis is critical. With the linea aspera as the only remaining anatomic guideline, the prosthesis is placed with the femoral neck anteverted about 5 to 10 degrees with respect to an imaginary perpendicular line from the prosthesis and a line drawn from the linea aspera through the body of the prosthesis (TECH FIG 8). Two bags of bone cement are usually required, and the cementing technique consists of pulsatile lavage, use of intramedullary cement restrictor, reduction of the cement by centrifugation, use of a cement gun, pressurization of the cement, and enhancement of the prosthesis-cement interface by precoating the proximal portion of the femoral or tibial stem with bone cement. While the bone cement hardens, the surgeons continuously verify the correct positioning of the prosthesis. P.278

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TECH FIG 7 • A,B. Modular components are assembled to fit the length of the resected specimen. C. Trial articulation. Leg length must be measured and neurovascular bundle evaluated for excessive tension. Schematic (D) and plain radiograph (E) of a total femur prosthesis, which is joined to a tibial component via a rotating hinge mechanism.

TECH FIG 8 • The prosthesis is positioned in 5 to 10 degrees of anteversion with the linea aspera being the only remaining anatomic guideline for proximal femur endoprosthetic replacements and the tibial tuberosity http://e-surg.com

for total femur endoprosthetic replacements.

▪ Soft Tissue Reconstruction Special attention is given to reestablishing hip stability and providing adequate muscle coverage of the prosthesis. The remaining hip capsule is sutured tightly with a 3-mm Dacron tape around the neck of the prosthesis, forming a noose that provides immediate stability (TECH FIG 9). Dacron is a nonabsorbable synthetic polyester (polyethylene terephthalate) that allows approximation of the cut ends of the joint capsule under considerable tension. It provides the initial mechanical support needed for healing and scar formation throughout the capsule. The surgeon cannot dislocate the prosthesis in a capsule that is adequately closed. Stabilization of the prosthesis is reinforced by rotating the external rotator muscles proximally and suturing them to its posterolateral aspect of the capsule. The psoas muscle is rotated anteriorly and tenodesed to the anterior capsule as additional reinforcement (TECH FIG 10). P.279

TECH FIG 9 • A-D. The remaining hip capsule is sutured tightly with a 3-mm Dacron tape around the neck of the prosthesis.

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TECH FIG 10 • A. The psoas muscle is rotated anteriorly and tenodesed to the anterior capsule as additional reinforcement. B. Alternatively, a circumferential polyethylene terephthalate tube may be applied on the prosthesis to which the surrounding muscles and tendons can be sutured. P.280 The extracortical component of the prosthesis can be used for additional bone and soft tissue fixation in the form of a noose around the prosthesis. Bone struts, either autografts or allografts, are held circumferentially with Dacron tape to the prosthesis-host bone interface. Theoretically, this procedure will prevent debris from entering the bone-cement interface and thereby reduce the possibility of aseptic loosening. If the greater trochanter had been resected en bloc with the surgical specimen, the remaining abductor tendon is attached with Dacron tape to the lateral aspect of the prosthesis through a metal loop. If there is a remaining fragment of the greater trochanter, it is fixed to the prosthesis with a cable grip system (TECH FIG 11A). Dynamic reconstruction is obtained by tenodesing the vastus lateralis to overlie the abductor muscle fixation. The remaining muscles are sutured to the vastus lateralis anteriorly and the hamstrings posteriorly (TECH FIG 11B,C).

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TECH FIG 11 • A. Fixation of the greater trochanter to the lateral aspect of the prosthesis with a cable grip system. B,C. The remaining muscles are sutured to the vastus lateralis anteriorly and the hamstrings posteriorly. D. The wound is closed over a 28-gauge chest tube that is attached to a continuous suction at 20 cm H2O. The wound is closed over a 28-gauge chest tube that is attached to a continuous suction at 20 cm H2O (TECH FIG 11D). The patient is placed in balanced suspension or tibial pin traction with the hip elevated and flexed 20 degrees.

PEARLS AND PITFALLS Preoperative evaluation

▪ Intracapsular tumor extension, option of sparing the greater trochanter, involvement of the neurovascular bundle

Intraoperative considerations

▪ If possible, preservation of joint capsule during resection and suture around the prosthetic neck during reconstruction ▪ Reattachment of the abductors to the prosthesis provides stability. ▪ Extracortical bone fixation provides stability. ▪ Functional reconstruction of muscle cuff, including the psoas tendon to the medial aspect of the prosthesis is necessary.

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POSTOPERATIVE CARE The extremity is kept in balanced suspension for at least 5 days. An abduction brace is customized for the individual patient. Continuous suction is required for 3 to 5 days, and perioperative intravenous antibiotics are continued until the drainage tubes are removed. http://e-surg.com

Postoperative mobilization with an abduction brace and weight bearing as tolerated are continued for 6 weeks. Active hip abduction is required before the brace can be removed and before unprotected, full weight bearing can be allowed.

OUTCOMES Over 80% of patients who undergo proximal or total femur resection report good to excellent function.1 Most of them do not require a walking aid (crutches, walker, or cane), although some extent of abductor insufficiency and Trendelenburg gait are common. No differences in function were found between patients who underwent proximal femur replacement and those who underwent total femur replacement.1 Dislocations of the prosthesis have become rare due to the combined use of capsular repair and reconstruction of the abductor mechanism. Because of the excellent blood supply around the proximal thigh and hip joint and the available options for prosthetic coverage with viable muscle tissue, flap ischemia, deep infections, and prosthetic loosening are rare.

COMPLICATIONS Deep infection Dislocation Abductor insufficiency and Trendelenburg gait Local tumor recurrence Prosthetic loosening

REFERENCE 1. Bickels J, Meller I, Henshaw RM, et al. Reconstruction of hip joint stability after proximal and total femur resections. Clin Orthop Relat Res 2000;(375):218-230. 2. Enneking WF, Shirley PD. Resection-arthrodesis for malignant and potentially malignant lesions about the knee using an intramedullary rod and local bone graft. J Bone Joint Surg 1977;59(2):223-236. 3. Freedman EL, Eckardt JJ. A modular endoprosthetic system for tumor and non-tumor reconstructions: preliminary experience. Orthopedics 1997;20:27-36. 4. Friesecke C, Plutat J, Block A. Revision arthroplasty with the use of a total femur prosthesis. J Bone Joint Surg 2005;87(12):2693-2701. 5. Hejna MJ, Gitelis S. Allograft prosthetic composite reconstruction for bone tumors. Semin Surg Oncol 1997;13:18-24. 6. Mankin HJ, Gebhardt MC, Jennings LC, et al. Long-term results of allograft replacement in the http://e-surg.com

management of bone tumors. Clin Orthop Relat Res 1996;(324):86-97. 7. Ottolenghi CE. Massive osteoarticular bone grafts. Transplant of the whole femur. J Bone Joint Surg 1966;48(4):646-659. 8. Zehr RJ, Enneking WF, Scarborough MT. Allograft-prosthetic composite versus megaprosthesis in proximal femoral reconstruction. Clin Orthop Relat Res 1996;(322):207-223.

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Chapter 25 Distal Femoral Resections with Endoprosthetic Replacement Jeffrey J. Eckardt Martin M. Malawer Jacob Bickels Piya Kiatisevi

BACKGROUND Ralph C. Marcove (Memorial Sloan Kettering Cancer Center) and Kenneth C. Francis (New York University Medical Center) introduced limb-sparing resection in the early 1970s for the management of malignant bone tumors, initially for osteosarcoma of the distal femur. The introduction of effective chemotherapy agents (doxorubicin [Adriamycin] and methotrexate) at the same time was a major impetus to the development of these procedures. These surgeons hoped that by combining surgery with chemotherapy, either preoperatively or postoperatively (termed adjuvant chemotherapy), limb-sparing surgery would be safe for the patient and would permit a limb-sparing resection. Distal femoral endoprosthetic reconstruction has undergone an evolution of surgical techniques and manufacturing changes (initially by Howmedica, Inc., Rutherford, NJ), making it one of the most satisfying orthopaedic oncology procedures available today. Forging of components has greatly diminished mechanical failure problems, and modularity has increased the indications for its use. Musclesparing and soft tissue coverage techniques have minimized wound healing problems. The three major steps in limb-sparing surgery—wide excision with good oncologic margins, reliable reconstruction of the skeletal defect, and adequate muscle transfer and good prosthetic coverage—have formed the basis for reliable and safe limb-sparing resections and reconstruction for both low- and high-grade bone sarcomas. Most clinical experience has been gained in treating osteosarcoma of the bone. The most common site is the distal femur and the proximal tibia. These techniques have subsequently been used for other bony sarcomas and recurrent benign tumors and more recently in the treatment of failed allograft and complicated, multifailed total knee arthroplasties. The goal is to have an adequate oncologic resection while maintaining enough muscle to permit a painless functional result. The techniques outlined in this chapter are based on the senior authors' (MM, JJE) 51 years of combined surgical experience, with approximately 440 distal femoral reconstructions since 1979.

ANATOMY The surgeon must be extremely knowledgeable of not only the bony anatomy and the specific endoprosthesis to be used but also the vascular anatomy, soft tissue structures, and potential local muscle flaps and the many techniques involved in a limb-sparing resection (FIG 1).

Sartorial Canal The sartorial canal occupies the space between the vastus medialis, sartorius, and adductor magnus muscles in which the superficial femoral artery passes the medial aspect of the thigh (adductor hiatus) and then enters the popliteal space. In patients with tumors longer than 13 cm, the sartorial canal is often displaced. The vessels within the canal are usually protected by the deep fascia of the vastus medialis and a tough fascia surrounding the vessels. This http://e-surg.com

fascia border is rarely penetrated by tumor.

Knee Joint The knee joint is rarely directly involved by sarcoma. The main mechanisms of knee joint contamination are inappropriate biopsy, extension of tumor along the intra-articular cruciate ligaments, and pathologic fracture. The knee joint can reliably be evaluated by computed tomography (CT) and magnetic resonance imaging (MRI). If the physical examination reveals any evidence of effusion, the knee joint should be aspirated and histologic samples obtained. A hemarthrosis usually indicates tumor involvement of the synovium. This is a rare event but not an indication for amputation.

Popliteal Space The popliteal space contains the popliteal artery and vein and the sciatic nerve. The popliteal vessels enter the popliteal P.283 space from the medial aspect through the adductor hiatus as the vessels exit the sartorial canal. The popliteal vessels are evaluated by CT with contrast, MRI, and plain angiography.

FIG 1 • Cross-sectional anatomy of the distal femur. It is rare to have direct vessel involvement by tumor. The vessels may be displaced as the tumor grows posteriorly, but usually, there is a normal border or margin of popliteal fat. Exploration of the popliteal space is the first step in determining the feasibility of a limb-sparing procedure. The http://e-surg.com

popliteal vessels are dissected out and the geniculate vessels are ligated. If the vessels are free of tumor, resection can usually be performed safely. A frozen section of the popliteal fat or adventitia of the popliteal vessels should be obtained intraoperatively. If there is obvious vascular involvement, the vessels can be replaced by vascular graft. The popliteal vein is usually not repaired because it rarely stays patent after surgery.

Anterior and Posterior Cruciate Ligaments The cruciate ligaments are occasionally involved by direct tumor extension from the distal femur. This occurs through the bone-tendinous junction of the intercondylar notch of the distal femur. There is no cartilage in this area to act as a barrier to tumor growth. MRI is occasionally helpful in determining cruciate ligament involvement. Tumor nodules of the anterior and posterior cruciates occasionally present with a hemarthrosis. The most common finding at resection is tumor nodule involvement of the cruciates. This does not rule out a limb-sparing procedure. The cruciate ligaments as they attach to the proximal tibial plateau can be resected en bloc with the proximal tibial cut. This is a safe procedure that avoids the need for a true extraarticular resection.

INDICATIONS Endoprostheses were initially used solely for reconstruction after resection of malignant bone tumors. Manufacturing time could be as long as 3 months, an interval that permitted induction chemotherapy. Endoprosthetic reconstructions proved to be enduring, and the designs have evolved (FIG 2).5,6 Modularity, which made for immediate availability, permitted the expansion of the indications for distal femoral endoprosthetic reconstruction to some stage 3 giant cell tumors of bone; metastatic disease where conventional intralesional procedures cannot reasonably be done, possibly 10% of metastatic cases; complex supracondylar fractures in elderly osteoporotic patients; failed internal fixation of distal femoral fractures; failed allograft or total knee reconstructions; and as a primary knee replacement system in patients with a severe flexion contracture where bone and ligament resection would lead to instability with conventional knee replacement systems.

PATIENT HISTORY AND PHYSICAL FINDINGS The average age of patients with high-grade osteosarcomas is 5 to 30 years; the median is 16 to 21 years. Surface osteosarcomas occur in the third decade and are more common in women. Patients with high-grade osteosarcoma almost always initially complain of pain during the day that is not associated with activity. All patients complain of a dull aching pain and only later of night pain. Thirty percent to 40% of patients have a history of local trauma. There is no causal relationship of trauma to the tumor except that it brings the patient to medical attention and the physician orders a radiograph, which always shows the tumor. This has been termed traumatic determinism. Classic high-grade osteosarcoma presents with pain. Parosteal osteosarcoma (surface osteosarcoma) usually presents with a mass and not pain (FIG 3). Parosteal osteosarcomas are most common in the posterior aspect of the distal femur. They represent less than 4% of all osteosarcomas. Popliteal fullness is a common finding. Plain radiographs can often distinguish a classic from a parosteal osteosarcoma. http://e-surg.com

There may be tenderness on examination. The regional lymph nodes are normal. Osteosarcomas spread hematogenously. Infection is rarely a consideration. Pathologic fracture occurs in less than 1% of osteosarcomas. Fractures usually occur through the purely osteolytic variant (about 25% of all osteosarcomas), which has minimal mineralized tumor matrix. A soft tissue, extraosseous mass occurs in more than 90% of high-grade osteosarcomas. An effusion usually indicates tumor involvement of the joint or pathologic fracture. Distal pulses are usually normal and symmetric. Decreased pulses may represent tumor involvement. Leg edema may represent popliteal vein occlusion or thrombus. Enlarged groin lymph nodes may represent lymph node metastasis, but this is rare. Biopsy should be considered. Popliteal lymph node enlargement is extremely rare (except for Ewing sarcoma or lymphoma).

IMAGING AND OTHER STAGING STUDIES Diagnostic imaging should include plain radiographs, a technetium 99 bone scan, an MRI of the entire femur, and a CT scan of the distal femur (FIG 4), as well as angiography. Three-dimensional CT angiograms have recently replaced routine angiography. Preoperative staging studies focus on the four anatomic structures discussed earlier. This permits the surgical team to determine the type of surgery, placement of the incision, the need for intra- or extra-articular resection, and the biopsy site and technique. Plain radiographs correlate very well with the extent of the tumor when a Codman triangle is present. A technetium 99 scan shows the extent of the tumor within the femur as well as the presence of skip metastases. Multicentric disease or metastases to other bones can be determined from this test as well. The early and pool phases of the bone scan demonstrate the vascularity of the tumor and tend to correlate with the chemotherapy effect (ie, tumor necrosis). A femoral MRI best shows the extraosseous extent of the tumor as well as its proximal and distal extent within the medullary canal. This study is the most accurate in detecting skip metastases. CT scans are complementary to MRI scans and can show the quality of the bone stock at the intended level of resection. Angiography or three-dimensional CT angiography can be used to evaluate the superficial femoral and popliteal arteries. This is especially important if there is a large posterior P.284 P.285 P.286 or medial extraosseous component. The late arterial phase of the angiogram or venous phase will show residual tumor blush. The degree of remaining vascularity correlates well with the tumor necrosis (FIG 5A,B). An unresponsive tumor as shown by a tumor blush requires a wider margin than a good responder (no tumor blush). More recently, three-dimensional CT angiography has replaced traditional angiograms; it shows the vascular anatomy well (FIG 5C-F).

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FIG 2 • A. Evolution of the distal femoral endoprosthesis. Composite no. 1: The Waldius knee mechanism, introduced in 1951, had a fixed metal on hinge. No. 2: The Spherocentric distal femoral endoprosthesis was developed by Harry Matthews, MD, in 1975 and first implanted in 1977. A metal ball and polyethylene cupola connected the tibial and femoral components. No. 3: The original kinematic rotating hinge knee was introduced in 1980. The Vitallium hollow body was casted by the lost-wax method, and a custom Zickel nail stem was welded to it. No. 4: Circumferential porous ingrowth beads were introduced in 1985 to allow for bone incorporation. In reality, little bone ingrowth occurred, but protective soft tissue ingrowth did. No. 5: Modularity was introduced in 1988. The condyles and femoral stems were forged and were coupled to titanium segments by Morse taper locks. Since its introduction in 1980 by Peter Walker for Howmedica, the kinematic rotating hinge knee mechanism has remained virtually unchanged except for a slight increase in the diameter of the axle and the polyethylene bushings. The rotating hinge knee concept has now been universally adopted as the preferred knee mechanism for distal femoral endoprosthetic reconstructions. B. A Guepar prosthesis (simple hinge) was used in the early 1970s before the development of the rotating hinge prosthesis. C. Custom prosthesis used during the 1980s. The knee joint is a rotating hinge consisting of bushings, axles, and a rotating polyethylene component that is inserted into the tibia. D. The modular replacement system (MRS) was first used (National Cancer Institute) in 1988 and was approved by the U.S. Food and Drug Administration in 1991. This http://e-surg.com

system consists of a joint component, multiple body segments, and stems of various diameters. This system can replace the proximal femur, distal femur, total femur, or proximal humerus. The original system was developed by the senior author (MM) in conjunction with the engineers (lead engineer George Corsi) at Howmedica (Rutherford, NJ). This system, now known as the Global MRS system, is manufactured by Stryker Orthopedics (Mahwah, NJ).

FIG 3 • Clinical photograph of an osteosarcoma of the distal femur. There is a large soft tissue mass (arrows). Ninety-five percent of all osteosarcomas have an extraosseous component.

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FIG 4 • A. Schematic illustration depicting the preoperative studies needed for sarcomas of the distal femur. MRIs, CT scans, bone scans, and angiography are required. B,C. Anteroposterior and lateral radiographs of a patient with a secondary chondrosarcoma arising from an osteochondroma. D. Posterior projection of a technetium 99 bone scan in a patient with a sarcoma of the distal femur. No skip metastases are noted. The uptake on the scan correlates well with the extent of tumor within the bone. (continued)

FIG 4 • (continued) E. The CT scan of the patient in B and C clearly shows the medial osteochondroma stalk from which the secondary chondrosarcoma arose. A posterolateral osteochondroma is also noted. Although soft http://e-surg.com

tissue extension of the tumor is apparent, it is less well delineated than on the MRI. F,G. Coronal and crosssectional MRIs of the patient. Together, these studies help to determine the resectability of the tumor as well as the desired level of the femoral osteotomy. A comprehensive knowledge of prosthetic stem lengths and widths is necessary to be sure that adequate proximal bone stock is available to proceed with endoprosthetic reconstruction.

SURGICAL MANAGEMENT Surgical guidelines for limb-sparing surgery are as follows: The major neurovascular bundle (popliteal vessels) must be free of tumor.

FIG 5 • Angiography after induction chemotherapy. A. Anteroposterior view. B. Lateral view showing the absence of a tumor blush. This is the most reliable finding of all preoperative staging studies that can predict tumor response. This patient had 100% chemonecrosis. C. Three-dimensional angiography is being evaluated in the treatment of bony tumors. (continued) P.287

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FIG 5 • (continued) C,D. Lateral and posterior views of the distal sarcoma. The popliteal artery is displaced. The extraosseous component is not visualized because there is no bony formation. E,F. Secondary chondrosarcoma of the proximal tibia. Lateral and posterior views showing excellent visualization of the popliteal artery and its trifurcation (arrows). A 64- or 246-slice CT scanner is required, similar to coronary angiography. The resection of the affected bone should leave a wide margin and a normal muscle cuff (ie, 1 to 2 cm) in all directions (FIG 6). All previous biopsy sites and all potentially contaminated tissues should be removed en bloc. All needle biopsy tracts must be removed (FIG 7A). To avoid intraosseous tumor extension, bone should be resected 3 to 5 cm beyond abnormal uptake, as determined by preoperative studies. The adjacent joint and joint capsule should be resected. Adequate motor reconstruction must be accomplished by regional muscle transfers. Adequate soft tissue coverage is needed to decrease the risk of skin flap necrosis and secondary infection. A medial gastrocnemius rotation flap provides excellent coverage of the prosthesis when required.

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FIG 6 • Primary distal femoral osteosarcoma: soft tissue resection. The small black dots represent potential skin metastases. The planes of a marginal excision and a wide excision are shown. Careful attention to the patient's general condition is critical in the timing of limb-sparing procedures in cancer patients. Patients undergoing preoperative chemotherapy (FIG 7B,C) and radiation therapy (Ewing sarcoma) need an adequate hiatus before surgery. In general, surgery can proceed 2 to 3 weeks after these treatments are completed. The white blood cell count and platelet count need to be within a safe range and rising, and the skin must have recovered from the effects of radiation and must be nonerythematous. When the procedure is used for a salvage reconstruction after failed internal fixation, failed total joint arthroplasty, or allograft procedures, a past history of infection can bode poorly if it is not completely eradicated before surgery.

Preoperative Planning The intended level of resection should be determined before the patient comes to the operating room. A careful review of the diagnostic tests should confirm this location and should confirm that there is adequate bone stock left to accept the femoral stem in terms of both length and width. The distal femur should be resected with a safe oncologic margin (3 to 4 cm of normal marrow). The extremity lengths should be equal to within millimeters. To http://e-surg.com

achieve this, intraoperative marks and measurements are made to ensure that the length before resection equals the reconstruction length. When planning the primary resection and reconstruction, the surgeon should also be planning an amputation or revision.9 Ideally, the level of amputation should be at the same level it would have been had amputation been chosen as the original procedure to achieve local control. The surgeon should plan how he or she will revise this reconstruction in the event of infection or mechanical failure. The real goal P.288 would be to retain the patient's own hip and not go to a total femur replacement unless necessary, as this requires rehabilitating two joints in series, which is always a greater challenge for the patient.

FIG 7 • A. CT scans of a sclerotic osteosarcoma of the distal femur. A needle biopsy is performed under CT guidance. Needle biopsies are routinely performed to establish a diagnosis; less than 5% to 10% require an open biopsy. B,C. Radiographic response after induction chemotherapy for a distal femoral osteosarcoma. B. Preoperative CT scan shows an extraosseous component. C. CT scan shows reossification of the entire lesion. CT scans are extremely valuable at determining tumor response (the percentage of tumor necrosis) and are routinely performed before and after induction chemotherapy.

Positioning In the preoperative area or as anesthesia is being induced, the patient is given intravenous antibiotics. One gram of vancomycin is slowly infused over 1 hour, and this is repeated every 12 hours until the drains are removed. A single 80-mg dose of gentamicin or tobramycin is also given. An epidural catheter is routinely used for postoperative pain management. After anesthesia is induced, a urinary catheter is placed. For the medial approach, the patient is placed in the supine position with the entire leg, including the inguinal area, prepared. This provides adequate access to the proximal femoral vessels.

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FIG 8 • A. Traditional subcutaneous approach to the distal femur and popliteal space versus the anterior transadductor popliteal approach. B. Incision used for distal femoral resection and distally if necessary for a medial gastrocnemius flap. A tourniquet is not used. A folded sheet placed transversely under the sacrum can elevate the pelvis to permit better access for draping. If the lateral approach is used, then the patient is placed in the lateral decubitus position on a beanbag with an axillary roll. A standard 10-minute preparation is performed, generally iodinebased.

Approach The preferred approach is a medial longitudinal approach with exploration of the superficial femoral and popliteal vessels. All vessels that feed the tumor and distal femur are tied off (FIG 8). A lateral approach is used only when access to the proximal femur is needed for cross-pin stem fixation or when little residual proximal femur remains. P.289

TECHNIQUES ▪ Resection and Reconstruction of the Distal Femur through a Longitudinal Medial Approach and Preparation for Cementing the Tibia, Patella, and Femoral Components Position and Dissection The patient is in supine position with the leg and inguinal area prepared out (TECH FIG 1A). The incision is longitudinal, following the sartorius muscle from proximally in the thigh distal to beyond the tibial tubercle (TECH FIG 1B). Any biopsy tract should be kept in continuity with the underlying tumor. Because the routine approach for primary tumors is medial, lateral or anterior open biopsy tracts need to be ellipsed and kept in continuity with the underlying tumor. The saphenous nerve is identified and protected (TECH FIG 1C). The interval between the sartorius and the vastus medialis is opened, exposing the superficial femoral artery and vein along with the saphenous nerve (TECH FIG 1D,E). The vessels and the saphenous nerve are dissected from proximal to distal and are reflected posterior and medial along with the sartorius muscle. http://e-surg.com

All vessels (geniculates) are tied off with 2-0 or 3-0 silk ties as they course from the vessels toward the distal femur and tumor (TECH FIG 1F). The surgeon must not ligate the medial or lateral sural vessels, which are the main blood supply to the respective gastrocnemius muscles. These vessels are the basis of a gastrocnemius flap if required. The surgeon should be careful at the canal of Hunter because the vessels are just deep to the adductor tendon. Distal to the canal of Hunter, the popliteal vessels are dissected free and reflected posterior and medially (TECH FIG 1G). The short head of the biceps muscle is now seen coursing proximal to distal to join the long head laterally in the thigh.

TECH FIG 1 • A. Right leg with large secondary chondrosarcoma. B. A medial incision follows the sartorius proximally in the thigh to below the tibial tubercle. This allows immediate and very adequate visualization of the femoral and popliteal vessels. C. After the incision through the skin and subcutaneous tissue, a large posteromedial flap is developed deep to the fascia. The first vital structure identified and protected is the saphenous nerve. It accompanies the femoral vessels proximally in the thigh and follows the sartorius into the leg. Cutting the nerve results in numbness over the medial calf and, occasionally, a painful neuroma. D. In the middle and distal thigh, retracting the sartorius posteromedially exposes the superficial femoral vessels. E. In the proximal thigh, retracting the sartorius anterior and lateral allows exposure of the femoral vessels all the way to the inguinal ligament if necessary. (continued) http://e-surg.com

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TECH FIG 1 • (continued) F. All vessels coursing toward the distal femur and tumor are tied with 2-0 or 3-0 silk sutures before they are cut. This minimizes blood loss, improves exposure, and guarantees the integrity of these structures. G. At the canal of Hunter, the adductor tendon is identified and cut. The main vessels are just beneath this structure, and care and patience at this point in the dissection are necessary. Several collateral vessels come off the femoral vessels at this point, coursing toward the femur and tumor. They need to be tied off. The saphenous nerve is seen accompanying the sartorius muscle. The sciatic nerve is exposed and protected. Proximal and medial in the thigh above the tumor, the junction between the adductors and vastus medialis can be opened to the femur to reflect the quadriceps laterally off the femur (TECH FIG 2A). Deep to the medial intermuscular septum is the terminal profunda artery and vein, which may be ligated. The superficial femoral vessels, along with the saphenous nerve and popliteal vessels, are dissected free from the tumor throughout its length to below the joint line (TECH FIG 2B,C). The medial gastrocnemius muscle can be incised. The surgeon must not ligate the medial sural vessels (TECH FIG 2D,E). With the femoral vessels completely dissected and reflected, the quadriceps or a portion of it, along with the patella and patellar tendon, are now reflected over the tumor, leaving the vastus intermedialis as a very satisfactory oncologic margin. Intra-articular resections are usually performed. The joint capsule is opened and the anterior and posterior cruciate ligaments, the popliteus tendon, and the collateral ligaments are cut with an electrical cautery.

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TECH FIG 2 • A. Proximally in the thigh, above the tumor, the adductor fascia meets the fascia of the vastus medialis. This interval is opened to permit exposure of the femur. The profunda vessels course just below the adductor fascia and follow the linea aspera. B. Saphenous nerve proximally in the thigh accompanies the superficial femoral vessels as the sartorius has been retracted posteromedially. The adductor tendon has not yet been cut, but the popliteal vessels have been exposed and mobilized to below the knee joint to guarantee their integrity. C. Completed medial dissection. The saphenous nerve follows the sartorius from proximal in the field. The femoral and popliteal vessels have been dissected and accompany the sartorius muscle and the saphenous nerve distally in the thigh. (continued) P.291

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TECH FIG 2 • (continued) D. Medially at the knee, the medial gastrocnemius muscle is dissected and cut. E. Medial geniculates are identified and cut. F. An arthrotomy has been made. The quadriceps had been dissected and mobilized over the tumor mass, leaving the vastus intermedius muscle as an oncologic margin on the tumor. G. Cortical marks have been made on the femur and tibia above and below the planned resection levels to establish the length before resection that should be reestablished with the reconstruction. The anterior cortical mark is placed at this time to help with rotation orientation. The posterior capsule is incised, with the popliteal vessels kept in direct view or under the operator's finger to prevent injury. Intra-articular extension of the tumor is rare; when it occurs, it is covered with synovium. Local recurrence, when it occurs, is generally along the neurovascular dissection plane and not anterior in, or in the level of, the knee joint. The quadriceps is reflected over the tumor, leaving a cuff of muscle on top of the tumor as the oncologic margin. The vastus intermedius is left as an oncologic margin over the tumor (TECH FIG 2F). Cortical marks are as follows: Before dislocating the knee, cortical marks are placed proximally on the femur and on the tibia, and the distance before resection is measured. This distance should be the same after the prosthesis is implanted. An anterior cortex is marked on the proximal femur to help with rotatory alignment during femoral stem insertion. This, along with the linea aspera, is used to determine appropriate rotatory position of the stem (TECH FIG 2G). The knee is dislocated and the short head of the biceps and the remaining posterior lateral capsule are cut. Osteotomy and Preparation of the Femur, Tibia, and Patella The femur is cut with a saw at the predetermined level (TECH FIG 3A-C). One more centimeter than the http://e-surg.com

assembled length of the femoral component is removed, and then only 7 mm is taken off the tibia. This 1.7 cm makes up for the distance between the prosthetic condyle and the undersurface of an 8-mm allpolyethylene tibial component when assembled. This ensures leg length equality (TECH FIG 4A). Alternatively, 17 mm can be taken off the tibia with jigs provided by the manufacturer, and the femur can be cut exactly at the proximal level of the segmental component. Although this may place the patella in a more anatomic location, it makes no difference in functional outcome (TECH FIG 4B). The proximal marrow is sampled and sent to pathology for frozen section analysis. The femur is reamed to accept the largest stem possible. This concept is “fit and fill.” Curved stems may add to rotatory stability. Stems smaller than 13 mm should be avoided in adults. The cut end is then chamfered (with a facing reamer) and cleaned with an irrigating brush (TECH FIG 4C-E). A proximal cement restrictor can be placed at this time if cement fixation is to be used. The tibia is osteotomized with an oscillating saw with a very slight posterior slope (TECH FIG 4F,G). This cut can be done freehand, although instrumentation is now available. Our routine is to take off only 7 mm, just below the cartilage. This leaves the largest surface area to support the reconstruction. An anterior slope will leave the final reconstruction with a knee flexion contracture. The proximal tibia is prepared to receive the tibial component. A distal bone plug or cement restrictor can be placed at P.292 this time. A trial all-polyethylene tibial prosthesis is then inserted. An intraoperative radiograph is taken to ensure that the cut is perpendicular to the shaft and not in varus or valgus. The seating of the trial prosthesis is also determined to avoid varus or valgus tilt (TECH FIG 4H).

TECH FIG 3 • A. The femur is cut with a Gigli or oscillating saw at the planned resection level and below the cortical marks. B,C. Anterior and posterior views of the specimen alongside the trial prosthesis. The undersurface (50%) of the fat pad is removed to prevent impingement. This can be painful in the immediate postoperative period. The patella undersurface is removed and it is prepared (undercut with a burr) to receive the patellar component. One of the senior authors (MM) routinely resurfaces all patellas with a single central peg component. Alternatively, if the patella appears normal (as in most adolescents), there is no need to replace it (TECH FIG 4I-L). A trial reduction is made and a measurement is taken to be sure that the postreconstruction distance is the http://e-surg.com

same as the preresection distance (TECH FIG 4M). Range of motion is tested: The quadriceps and patella should track nicely without a tendency for lateral dislocation. A lateral release should be made at this time if there is a tendency for patellar subluxation or dislocation. The tension of the superficial femoral vessels is also checked. The distal pulses at the ankle are checked with a Doppler with the reconstruction in full extension. Overlengthening can cause excessive tension and compression of these structures. Overlengthening should be avoided. It is harder to rehabilitate a lengthened extremity. Leg length inequalities in the growing child can be made up at a later date with an exchange of one of the segmental modules rather than overlengthening at the time of the initial resection. Some adolescent patients never need a lengthening. Overlengthening also increases the risk of sciatic or peroneal nerve palsy. Selection and Placement of the Components The patellar component should not overhang the cut surface of the patella. A central peg polyethylene component is used and the surface of the bone is undercut to aid in fixation. The rationale for resurfacing the patella is that it allows immediate and vigorous rehabilitation without concern that any knee pain may be due to the patellar cartilage grinding on the metal distal femoral prosthesis. This is more important given that the goal is an active range of motion of 120 to 130 degrees of flexion, full extension, and no extensor lag. This is routinely achieved. If the expectation of active knee motion is 90 degrees or less, then it probably does not make any difference whether the patella is resurfaced or not. The all-polyethylene tibia is almost always 8 mm in primary cases. Metal-backed tibial components are not necessary in primary cases but are routinely used in revisions. The tibial polyethylene is oriented to face the tibial tubercle (slight external rotation). The femoral component is picked to maximize the fit and fill concept and is oriented anatomically based on the anterior cortical mark and the linea aspera. The actual components are assembled on the back table, and another trial reduction is performed to check lengths, the tension of the vessels, and distal pulses as well as tracking of the patella. All of the tapers must be dry before impaction because a “wet” taper will cause unlocking or disassociation. Cementing of Components All components are cemented. Before cementing, 100 mg of hydrocortisone (Solu-Cortef) is given intravenously to protect against fat embolism. The deleterious effects of a fat embolism are due to a massive inflammatory response in the lungs. Steroids are the best anti-inflammatory agent. P.293

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TECH FIG 4 • A. With this author's (JJE) technique, the femur is cut 1 cm longer than the planned femoral replacement. B. Only 7 mm is removed from the proximal tibia. This gives the largest platform for the tibial component. An 8-mm all-polyethylene tibial component is routinely used in primary reconstructions. The distance from the metal condyle to the inferior surface of an 8-mm polyethylene tibial component is 1.7 cm. This ensures extremity length equality to within millimeters. No effort is made to keep the patella right at the knee joint. Patellar tracking and postoperative function, which is what is important, are routinely excellent. C. After the marrow frozen section report has returned as negative for tumor, reaming the canal can commence, with the femur stabilized with a large locking clamp. Sharp reamers are used and the reaming is done slowly and gently, with copious irrigation to prevent a fat embolus. The canal is reamed to whatever level is necessary to permit the largest stem to fit easily. D. A chamfer reamer is used to prepare the osteotomy site. E. The canal is cleaned again slowly and gently with an irrigating brush. F. A freehand oscillating saw removes 7 mm from the upper tibia. Manufacturers now provide tibial cutoff instrumentation to permit the removal of larger amounts of tibia to keep the patella at the joint line. G. The tibial cut is usually perpendicular when the distal end points to the second metatarsal. The tibial cut should have a slight posterior slope to ensure full extension when the prosthesis is fully extended. If the slope is anterior, the patient will be left with a built-in flexion contracture. (continued) P.294 http://e-surg.com

TECH FIG 4 • (continued) H. An intraoperative radiograph is taken to ensure that the cut is perpendicular. Slight varus or valgus does not seem to interfere with function or lead to loosening. I. The undersurface of the patella is removed with an oscillating saw. J. It is prepared for a central peg all-polyethylene component by undercutting the hole with a burr. K. Instrumentation is available to prepare the tibia to receive the tibial component. The prepared patella and tibia are seen. L. The trial patella component overhangs the patella and should be replaced with a smaller component. M. The reconstruction length is measured from the tibial to the femoral mark to ensure equality with the length before resection. Ankle pulses are checked at this time. Antibiotic-impregnated cement is routinely used. The tibial component and the patella are cemented first. The cement is injected while it is still fairly liquid, and the femoral canal is pressurized. The femoral stem is inserted slowly. Rapid insertion can lead to a fat embolism. Once the stem is placed, rotatory changes are avoided because they will lead to poor fixation and early loosening. No last-minute adjustments should be made on the femoral side.

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TECH FIG 5 • A. Final reconstruction. B. Final reconstruction and resected specimen. A final measurement is made once the final components are in place. The final reconstruction with and without the resected specimen can be seen in TECH FIG 5A,B. Closure and Postoperative Care Before closure, homeostasis should be meticulous. The wound is irrigated copiously with antibiotic solutions, with all final rinses with saline solutions. P.295 The joint capsular tissue is closed to the remaining capsular tissue about the proximal tibia. The sartorius is sutured to the vastus medialis over a deep 10-mm flat drain with a no. 1 absorbable suture (TECH FIG 6). The subcutaneous tissue is closed over a superficial 10-mm flat drain. The drains are sutured in place and are kept in place until the 24-hour drainage is less than 30 to 40 mL per hour. Skin closure can be with staples or a subcuticular suture. Gastrocnemius flaps are necessary in less than 1% of cases but can be useful to cover an endoprosthesis if adequate tissue is not available. More common use of the gastrocnemius flap reflects an individual surgeon's resection philosophy and technique. Sterile dressings and an Ace wrap are applied. The patient is placed in the bed with a continuous passive motion machine, flexing to 30 degrees and extending to −5 degrees for 3 days. The range of motion is then advanced rapidly to achieve 90 degrees of flexion before discharge. Sequential compression boots are applied to the feet. The next technique, from an anterior (transadductor) approach, may be used as an alternative.

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TECH FIG 6 • Closure: Two large, flat 10-mm drains are placed and exit proximally. The sartorius is sutured to the remnants of the vastus medius. The distal capsule is closed.

▪ Resection and Reconstruction of the Distal Femur through a Longitudinal Lateral Approach and Preparation for Cementing the Tibia, Patella, and Femoral Components Indications for the lateral approach: All revision cases Total femur reconstructions Primary distal femoral tumors that extend so far proximally that cross-pin stem fixation, either at 90 degrees to the shaft or 135 degrees into the femoral neck, is necessary to achieve a stable reconstruction2 Patient preparation for the lateral approach is identical to the medial approach. Once anesthesia is administered, the urinary catheter is placed, and the vancomycin and gentamicin are administered, the patient is rolled to the lateral decubitus position, with all pressure points carefully protected. The entire leg is draped and prepared from above the iliac crest to the foot. A tourniquet is not used. A longitudinal lateral incision is made from the tibial tubercle to as far proximal as necessary. It can be extended to the tip of the trochanter and then on to the anterior superior iliac spine if a total femur endoprosthesis is planned. The skin and subcutaneous tissues are incised with an electrical cautery knife. The fascia lata is incised in line with its fibers. The lateral intermuscular septum is identified and the entire vastus lateralis can be released from its posterolateral insertion after tying all the perforators before cutting them. Then the entire vastus lateralis can be flipped up over the femur, exposing the entire length of the bone. A cuff of muscle can be left on the tumor as oncologic needs dictate. Because the tibial tubercle is a somewhat laterally placed structure, care needs to be taken to avoid http://e-surg.com

avulsion of the patellar tendon. The remainder of the procedure is identical to the medial approach.

▪ Anterior (Transadductor) Approach to the Distal Femur and Popliteal Space for Resection of Tumors of the Distal Femur and Endoprosthetic Reconstruction The traditional approaches to the distal femur are medial and anteromedial.10,13 These techniques facilitate access to the anterior aspect of the femur and allow exploration of the popliteal fossa and mobilization of its neurovascular structures by developing large fasciocutaneous or subcutaneous flaps (TECH FIG 7). Because some of the blood supply to the skin and subcutaneous tissue is inevitably compromised during the development of the flaps and because all the geniculate vessels are routinely ligated as part of the resection of the distal femur, the risk for ischemic flap necrosis is increased.7,10,11,12 In addition, separating the vastus medialis from its fascia and subcutaneous tissue compromises the vascularity of the outer layer of the muscle. Consequently, resection of the inner portion of the vastus medialis, which often is oncologically necessary, compromises the vitality of its residual outer layer and often prevents adequate soft tissue coverage of the endoprosthesis. In a previous study by the senior author (MM) of 110 distal femoral resections P.296 P.297 and endoprosthetic reconstructions using the anteromedial approach, 25 gastrocnemius flaps were required due to insufficient soft tissue coverage and flap necrosis.1

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TECH FIG 7 • A-C. Surgical approach using the newly described anterior (transadductor) approach to the distal femur. This approach was developed to avoid postoperative skin flap necrosis. The vastus medialis remains attached to the overlying skin, essentially forming a myocutaneous flap. A. Wide skin flaps are developed, and the interval between the rectus (RF) and the vastus medialis (VM) is carefully opened. B. The RF and VM interval has been opened, showing the fibers of the vastus intermedius tendon. C. The distal aspect of the VM is developed. D. The surgical approach shown in A-C. E. The vastus intermedius tendon is opened and the medialis is mobilized. F-K. The transadductor approach. F. The interval between the RF and VM has been opened and the vastus intermedius has been mobilized. G. The termination of the sartorial canal containing the superficial femoral artery and vein is dissected free. (continued)

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TECH FIG 7 • (continued) H. The sartorial canal has been opened. I. The remaining attachment of the adductor magnus tendon to the distal femur is released. J. Relationship of the superficial femoral artery to the popliteal space and the adductor magnus tendon. K. Exposure of the popliteal space and the neurovascular structures. The geniculate branches are carefully ligated. The vastus medialis has remained attached to the overlying skin, thus emphasizing the purpose of this approach. Kawai et al reported a flap necrosis incidence of 30% in a series of 40 patients who underwent distal femoral resection and endoprosthetic reconstruction, and Safran et al concluded that perioperative chemotherapy and intraoperative flap devascularization were the major causes of infection after limbsalvage procedures.14 In an attempt to decrease the occurrence of flap necrosis and to improve the soft tissue coverage of the endoprosthesis, the senior author (MM) has developed the following modified surgical approach for distal femoral resection using a well-vascularized posteromedial myocutaneous flap: Indications All high- and low-grade tumors of the distal femur All distal femoral revisions. If a lateral interlocking hip nail is required, a separate proximal, lateral, standard hip-like incision is made. There is no need to connect these two incisions. If soft tissue closure is considered to be a problem, this approach is recommended. This allows for a medial gastrocnemius flap by simply extending the incision distally. The medial gastrocnemius muscle is always preferred to a lateral gastrocnemius muscle because it is larger and longer than the lateral gastrocnemius muscle. It permits a larger area to be covered both longitudinally and transversely across the prosthesis and knee joint, respectively. (See Medial Gastrocnemius Muscle Transfer in the later section.) This incision creates a myocutaneous flap by keeping the vastus medialis muscle attached to its overlying skin. Skin flap necrosis, wound dehiscence, hemarthrosis, effusions, and other wound problems are rare (1% to 5%). If vascular resection and reconstruction are preoperative possibilities, the superficial femoral and http://e-surg.com

popliteal vessels are directly exposed. A lateral incision would make vascular reconstruction more difficult. If minimal muscle coverage remains a problem after resection and attempted closure, the sartorius muscle can be rotated to cover small defects. In addition, a formal sartorius muscle transfer can be performed through this incision to recreate or to replace either partial or complete vastus medialis loss. Position and Incision With the patient in the supine position and the surgeon standing on the medial side of the knee (opposite side of the table), a long, medial paramedian skin incision is made. The incision extends proximally along the junction of the rectus femoris and vastus medialis muscles and curves distally around the medial border of the patella to the level of the pes anserinus. Proximal Interval and Creation of Musculocutaneous Flap The interval between the rectus femoris and vastus medialis muscles is identified and opened to expose the underlying P.298 vastus intermedius muscle. The fibers of the vastus intermedius are then carefully divided. It is important not to separate the overlying muscle from its fasciocutaneous coverage, which would defeat the purpose of this approach. This can be ensured by suturing the vastus medialis to the overlying skin. Exposure of Intermuscular Septum and Adductor Hiatus The plane between the vastus medialis and the medial femoral condyle is identified distally (similar to the subvastus approach). The vastus medialis muscle is dissected off the medial femoral condyle in an extraarticular fashion and retracted medially, away from the knee capsule. By sweeping the fibers of the muscle from the intermuscular septum with a sponge, the intermuscular septum, the adductor hiatus, and the adductor magnus tendon are exposed. Identification of the Superficial Femoral and Popliteal Vessels The sartorius muscle, which crosses over the proximal portion of the vastus medialis, is mobilized posteriorly by opening the thin fascia between the vastus medialis and its superior border. The superficial femoral artery and vein are identified proximally at the level of the adductor hiatus. With the surgeon's finger placed into the adductor hiatus to protect the underlying vessels, the distal portion of the adductor magnus tendon is dissected and released from the distal femur and adductor tubercle, partially exposing the popliteal space.

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TECH FIG 8 • A. The knee is flexed to permit exposure of the popliteal space and the vascular structures. The origin of the medial gastrocnemius muscle is released, permitting easy exposure of the distal end of the popliteal vessels. B. Surgical defect. In general, the defect ranges from 15 to 20 cm. C. Trial prosthesis. Care must be taken not to stretch the neurovascular structures and to equalize leg length. D. The permanent prosthesis has been inserted. This design promotes fibrous and bony ingrowth and prevents stem loosening. The superficial femoral vessels are carefully dissected and mobilized along their sheath, and vessel loops are placed around them as they enter the popliteal fossa. Completion of Popliteal Exposure The knee is placed in 90 degrees of flexion. With the vastus medialis musculocutaneous flap retracted posteriorly, the entire popliteal space is visualized and the popliteal vessels are identified distally between the two heads of the gastrocnemius muscle. After the identification of the popliteal vessels, the medial head of the gastrocnemius is released from the femoral condyle; this should be performed with the surgeon's finger placed underneath the muscle, protecting the popliteal artery and vein. Care should be taken to preserve the medial sural artery, which is the sole vascular supply to the medial head of the gastrocnemius (TECH FIG 8). Mobilization of the Popliteal Vessels and Sciatic Nerve Mobilization of the popliteal vessels is facilitated by individually ligating their geniculate branches from the level of the adductor hiatus to the junction of the gastrocnemius muscle. A downward P.299 traction maneuver of the vessels allows better identification of the geniculate branches. The sciatic nerve is then exposed over the proximal portion of the popliteal fat and followed distally to its bifurcation into the tibial and common peroneal nerves. The popliteal vessels are then covered by a http://e-surg.com

sponge soaked in papaverine to prevent potential vasospasm. Release of Lateral Structures After complete exposure of the popliteal space, including release of the medial head of the gastrocnemius and mobilization of the popliteal vessels, the lateral head of the gastrocnemius muscle, the short head of the biceps muscle, and the entire posterior capsule are released. Anterior (Intra-articular) Release and Distal Femoral Osteotomy To complete the soft tissue dissection of the distal femur, the anterior capsule is opened transversely and both cruciate ligaments are divided. With the superficial femoral vessels mobilized, the femoral osteotomy, which is usually made 15 to 20 cm proximal to joint line, above the level of the adductor hiatus, can now be safely performed. The following steps to complete the resection and reconstruction are identical to those discussed earlier: Intra-articular resections Cortical marks Osteotomy and preparation Trial reduction Selection and placement of the components Cementing Closure Medial Gastrocnemius Muscle Transfer The medial gastrocnemius muscle is the mainstay of muscle transfers of the distal femur. The technique of medial gastrocnemius transfer for difficult and complicated distal femoral resections was initially described by Malawer and Price in 1985 (TECH FIG 9). This muscle transfer provides excellent coverage for small and large medial and anterior defects after distal femoral resection. It has been our experience that a free flap has never been required after distal femoral resection and endoprosthesis replacement.

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TECH FIG 9 • A. Incision. B. The medial gastrocnemius flap is detached distally and through the midline between the medial and lateral gastrocnemius muscles. This permits easy rotation. (continued) P.300

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TECH FIG 9 • (continued) C. The gastrocnemius muscle is now rotated to cover the prosthesis and the joint. Muscle coverage is essential to permit wound healing and to avoid infections. D,E. Medial gastrocnemius flap. D. The medial gastrocnemius flap has been mobilized. E. Now sutured in place, this flap closes the defect. The muscle is tenodesed to the vastus medialis muscle, the patella, and the soleus muscle distally. P.301 The medial gastrocnemius muscle is dissected free of its tendinous and midline insertions in the calf after cementing of the prosthesis. It may then be rotated transversely or proximally, depending on the area to be covered. Usually, the skin can be closed directly over the transferred muscle, but if there is any skin tension or swelling, the skin flaps are sutured directly to the muscle transfer and the remaining defect is closed with a split-thickness skin graft onto the muscle directly at the time of surgery. There is a thick fascia covering both the anterior and posterior surfaces of the medial gastrocnemius muscle. These fascia coverings are routinely removed with a sharp blade. This permits the muscle to expand about 150% larger than normal. The muscle can then be rotated either proximally to cover large medial defects or anteriorly to cover the entire exposed knee joint. The arc of rotation may be increased by

releasing the sartorius and the other pes muscles. These muscles are then tenodesed to the transferred gastrocnemius muscle after rotating the gastrocnemius into place.

TECH FIG 10 • Perineural technique of catheter placement for postoperative pain control. We use a continuous infusion of 0.25% bupivacaine at 4 to 8 mL per hour. A. Intraoperative photograph shows the nerve and catheter in relationship to the prosthesis. B. The sciatic nerve sheath has been opened and the catheter is placed. C. The catheter is brought out of the wound via an angiocatheter, which is then removed. The medial gastrocnemius muscle is fed by one major branch: the medial sural artery off the popliteal artery. The origin of this branch is at or below the knee joint line. At the time of popliteal exploration and dissection, it is essential to preserve this branch and not mistake it for a geniculate vessel. Geniculate branches pass anterior from the popliteal artery, whereas the medial sural artery passes posterior and medial. This vessel usually takes off at about the level of the inferior geniculate pedicle. The lateral gastrocnemius is rarely used because it is a much smaller muscle and its arc of rotation is decreased by the peroneal nerve and the fibula. Pain Control Silastic epineural catheters are routinely placed (MM) in the femoral nerve sheath and a 10-mL bolus of 0.25% bupivacaine is infused before the patient is transferred to the recovery room. Four to 8 mL per hour is administered using an infusion pump for up to 72 hours postoperatively. This provides excellent pain control and decreases systemic narcotic requirements by more than 50% (TECH FIG 10).

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PEARLS AND PITFALLS

Difficulty closing the wound

▪ Difficulty in wound closure usually occurs as a result of significant muscle resection due to the oncologic need for adequate margins. A too-long leg can cause this problem. The level of the patella should be checked. ▪ A medial gastrocnemius muscle flap should be used if there is any question about the viability of the medial closure or if a significant amount of the vastus medialis has been resected. Occasionally, the sartorius muscle can be rotated to close a small defect instead of the gastrocnemius muscle.

Identifying surgical planes medially and the subvastus interval

▪ The surgeon should carefully identify the vastus medialis and rectus femoris interval and the subsequent vastus intermedius below it. The vastus medialis is mobilized extra-articularly from the femoral condyle.

Mobilization of the superficial femoral vessels

▪ These vessels are identified within the sartorial canal and traced to the adductor hiatus. The surgeon places a finger into the hiatus before releasing the adductor fibers and intermuscular septum.

Difficulty identifying the popliteal vessels, especially distally

▪ The surgeon should release the medial gastrocnemius muscle within 1-2 cm from its insertion onto the medial condyle. The popliteal vessels are found between the two heads of the gastrocnemius muscles.

Injury to or ligation of the medial sural artery

▪ The medial sural artery is the main pedicle to the medial gastrocnemius muscle. This branch comes off medial and posterior from the popliteal artery. The geniculates take off anteriorly. The surgeon must not ligate any “geniculate” if it appears to be running medial or posterior.

Injury to the sciatic nerve, especially the peroneal branch

▪ The sciatic nerve is easily identified in the popliteal space covered by fat posterior to the popliteal vessel sheath. These two sheaths are separate in the proximal portion of the popliteal space. Only after the sciatic nerve divides does the tibial nerve join the popliteal vessels within a common sheath. The peroneal nerve runs lateral to exit the popliteal space and runs lateral to the lateral gastrocnemius muscle. The nerve can easily be injured at this level, especially when the lateral gastrocnemius is released from the femoral condyle.

Injury to the popliteal artery and vein

▪ Although these vessels are initially identified and mobilized, they can be iatrogenically injured later in the procedure. The surgeon must be careful when releasing the posterior capsule. The popliteal vessels are tied down to the capsule at the joint line by the most inferior geniculate vessels. These vessels should be ligated early in the procedure so that the popliteal vessels fall away from the entire femur and capsule. ▪ Occasionally, the popliteal vessels are punctured by the distal end of the osteotomized femur. The surgeon should pack off the distal femur with a laparotomy pad to avoid this.

Absent pulses after closing the wound

▪ This is most common in young patients with small-diameter vessels. It is often due to severe vascular spasm, usually secondary to small vessels, long length of vessels exposed, and exposure to the cold operating room air. It is best to avoid this situation by placing papaverine (vasodilator)-soaked sponges and warm laparotomy pads on the vessels throughout the procedure. ▪ If this does occur, the surgeon must ensure that the vessels are intact and not kinked off or thrombosed secondary to traction, intimal damage, or iatrogenic ligation. An intraoperative angiogram and a vascular surgeon consultation should be obtained. In most cases, the wound should be opened and the popliteal vessels quickly explored. The vascular surgeon may choose to pass Fogarty catheters to make sure there is no thrombus, but this technique is also a good means of opening a severely spasmed artery.

Unequal leg lengths

▪ Taking careful measurements before resection and after implantation ensures leg length equality to within millimeters.

Fitting and filling the femoral canal

▪ Ream up the femoral canal to maximize fit.

Tying vessels before cutting

▪ Tying vessels before cutting minimizes blood loss and improves visibility.

Cementing all components, including the patella and allpolyethylene tibia

▪ We have had no patellar or proximal tibia polyethylene failures in 25 years. Cementing permits aggressive rehabilitation.

Preventing fat embolism

▪ Ream the canal slowly, insert the stem slowly, and pretreat with 100 mg of hydrocortisone (Solu-Cortef) before cementing.

Preventing patellar dislocation

▪ Ensure soft tissue balance; perform a lateral release if necessary before closure.

Unwillingness to plan for and do the revisions

▪ A surgeon unwilling to plan for and do revisions should probably not be doing the primary resections and reconstructions.

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POSTOPERATIVE CARE In the operating room, the patient is placed in the bed with a continuous passive motion machine, flexing to 35 degrees and extending to −5 degrees. That range of motion is maintained until the third day, when it is advanced 10 to 15 degrees a day to achieve 90 degrees before discharge. The inpatient stay is generally 7 to 10 days. A towel roll is placed under the heel three times a day for 60 minutes to ensure that full extension is achieved and that a flexion contracture is avoided. This practice is continued for the first 4 weeks after surgery. The patient is mobilized out of bed on the third postoperative day and ambulated initially with a walker and then crutches and with a knee immobilizer, which is kept on for 4 to 8 weeks when out of bed. Before discharge, the patient should be able to flex to 90 degrees and do 10 straight-leg raises with the knee immobilizer on, should be in and out of bed independently, and able to go up and down stairs. The drains are removed when the drainage in a 24-hour period is less than 30 to 40 mL in each drain; generally, this is in 5 to 6 days. Intravenous antibiotics are continued until the drains are removed. Anticoagulation after surgery is based on the patient's risk factors. A circumferential compression Ace wrap is used for 2 months, and sometimes, a Neoprene knee brace is used for several months. Outpatient physical therapy is begun 4 to 6 weeks after surgery and lasts for 12 weeks. The goal is to maximize knee flexion, motor strength, and gait. Most patients achieve more than 120 degrees of flexion, have full extension without a lag, and walk without a limp. By 4 months, the patient should be able to walk down the hall and most observers would not be able to tell that he or she has had surgery.

OUTCOMES In a study by Bickels et al,1 110 patients diagnosed between 1980 and 1998 with lesions of the distal femur underwent distal femur resection and endoprosthetic reconstructions. Extra-articular resection of the knee occurred in only 2 of these patients, both of whom were diagnosed with a primary bone sarcoma with tumor extension into the knee along the cruciate ligaments. Reconstruction implants included 73 modular prostheses, 27 custom-made prostheses, and 10 expandable prostheses. Only eight patients had a constrained knee mechanism (earlier edition); the remaining patients had reconstruction with a rotating hinge knee mechanism prosthesis. Twenty-one medial, three lateral, and one bilateral gastrocnemius flaps were used after resection for soft tissue reconstruction. Ten patients with

expandable prostheses had 14 lengthening procedures performed. Patients who had reconstruction with a rotating hinge knee mechanism were more likely to have a good to excellent functional outcome (91%) than those who had reconstruction with a constrained knee mechanism (50%).

COMPLICATIONS Complications in the study mentioned earlier included 6 deep wound infections (5.4%), 3 of which resulted in amputation, 2 prosthetic revisions, and 1 wound débridement. Overall, there were 15 revision surgeries; they entailed replacement of a failed polyethylene component in six patients and prosthetic revision in nine patients (aseptic loosening, six; deep infection, two; radiation bone necrosis, one) (FIG 9). Two of the polyethylene component failures occurred in the same patient; the first occurred 2.5 years after the initial surgery and the second occurred 3.8 years later. Polyethylene failures occurred after an average of 3.7 years (range 1.25 to 7.25 years) and aseptic loosening occurred after an average of 5.5 years (range 3.2 to 10.3 years). During revision of their prostheses, all patients who underwent additional surgery because of a loosened prosthesis were found to have concomitant failure of a polyethylene component.

Local Recurrence The risk of local recurrence is surgeon-dependent. It occurs independent of the type of reconstruction (arthrodesis, allograft, or endoprosthesis).

FIG 9 • Survival of the distal femoral prosthesis. Kaplan-Meier curves of prosthetic survival. A. Custom versus modular prosthesis survival for all anatomic sites. The difference is mostly due to changes in surgical technique and reconstruction of the soft tissues. B. Endoprosthetic survival versus actual patient survival. The prosthesis is extremely reliable over the patient's lifetime. (continued) P.304

FIG 9 • (continued) C. Survival of all distal femoral prostheses. D. Prosthetic survival by various anatomic sites.

Infections Infections are related to the local environment at surgery, bacteremias in the immediate postoperative period, length of the surgery, and soft tissue coverage problems. Infections are also generally independent of the type of reconstruction, although the rate is significantly higher in allograft reconstructions (FIG 10). Twenty-five percent to 30% of deep periprosthetic Staphylococcus aureus or Staphylococcus epidermidis infections can be salvaged if treated early with aggressive and radical débridement, including prosthesis removal, implantation of antibiotic-impregnated cement spacers, and 6 to 8 weeks of intravenous antibiotics, followed by reinsertion of the components if aspirations are negative. Most other bacterial infections and all the gram-negative infections are difficult to cure and can lead to amputation.

FIG 10 • Deep prosthetic infection. A. Gross purulence in the knee joint. B. It is important to remove the synovium and pseudocapsule. The prosthesis is typically removed as well. C. A large vacuum-assisted closure (VAC) sponge covers the defect. The sponge is sutured to adjacent muscles. D. VAC after application of suction. The dressing must be changed every 1 to 2 days. An exposed prosthesis is another cause of infection. Although needed infrequently by one author (JJE),

rotation flaps and free flaps have been advocated and used to solve this problem. Their frequent application in primary cases reflects the individual surgeon's resection philosophy and techniques.3,4

Fat Embolism Fat embolism can result from a number of factors, alone or in combination. Reaming the canal should be done slowly P.305 and gently with sharp reamers and frequent irrigation and suction. Although cement restrictors and pressurization of the cement are regularly used, stem insertion is again done gently and slowly. Patients should be well hydrated and oxygenated before insertion of cemented femoral stems. Fat emboli cause a massive inflammatory reaction. Because steroids are the best anti-inflammatory medication, 100 mg of hydrocortisone (Solu-Cortef) is routinely administered before cementing and insertion of long intramedullary stems. Massive fat emboli can be fatal.

Mechanical Failures Mechanical failures include fatigue fracture of any endoprosthetic metal or polyethylene component, aseptic loosening, disassociation of modular components, and polyethylene wear synovitis (see FIG 9). Most mechanical failures can be revised. The key to success is to analyze the failure mode and not do the same reconstruction. Although the literature suggests that revisions have a 50% failure rate at 5 years, if you analyze the failure mode and correct it, the revision should last longer than the original reconstruction.13 The rotating hinge knee was introduced in December 1980 and has become the international standard knee mechanism for distal femoral knee reconstructions. Anteroposterior stability and mediolateral stability are built into the mechanism, which permits complete resection of all the knee ligaments, a necessity in all tumor resections. The capacity to rotate slightly with loading defuses stress at the bone-prosthesis or the bone-cement-prosthesis interfaces, diminishing aseptic loosening and fatigue fracture.7 The development of modular components with forged stems has greatly reduced the incidence of fatigue fracture, especially of the femoral stems, compared with casted stems. This is unless there is a mismatch between the patient size and the implant size: An 11-mm stem in a 250-pound patient is a recipe for failure.

Bushing Failures and Pseudomeniscus Formation Bushing failures are heralded by the sudden onset of knee joint pain and a sense of instability to the point that ambulatory aids are necessary. Only on rare occasions, when there is complete disintegration of the bushing and extensor stop, will the radiographs be positive with medial or lateral protrusion of the axle. Surgical exploration, therefore, is done because of a high index of suspicion. This tends to be a late complication: The median time to failure in a series of seven cases was 84 months (range 30 to 112 months; FIG 11).

Pseudomeniscus and Internal Derangement of the Knee The term pseudomeniscus refers to scar tissue formation between the moving components of the femoral condyles on the tibial bearing component as well as under this component and the cemented allpolyethylene (within the tibia). Scar tissue over time and with constant motion will form a true fibrocartilage type of scar that takes the shape of a true meniscus. Pseudomeniscus formation occurs frequently but is symptomatic in only a few patients. The symptoms are usually subtle, often presenting as an internal derangement of the knee. The most suggestive signs are a feeling of instability, combined with slight valgus instability (>5% on a stress test), and with or without a

small effusion. There are no real diagnostic tests. Suspicion is the key to diagnosis. These symptoms may mimic those of a bushing failure but with less instability and a smaller effusion. The true incidence of symptomatic pseudomeniscus is 5% to 7%. The treatment is resection of the pseudomeniscus as well as the pseudocapsule in the hope of preventing a recurrence.

Stem Fracture The incidence of femoral stem fractures has been reduced significantly with the introduction of forged stems, but they P.306 P.307 can occur, especially if the stem is undersized compared to the weight of the patient. Stem loosening usually precedes catastrophic fatigue fractures and may present as an actual displaced bone fracture.

FIG 11 • A. Breakage of medial bushing. B. Close-up of residual bushing. (continued)

FIG 11 • (continued) C. Delamination of a bushing and bumper. D. Delamination of a polyethylene bumper removed 17 years after surgery. E. Clinical photograph showing gross instability to a varus stress test. This instability is characteristic of worn or broken bushings. F,G. Patients with pseudomenisci present with localized pain, lack of full extension, and no effusion. H. Gross specimen of a pseudomeniscus. This is formed by thick fibrous collagen without an inflammatory component. Pseudomeniscus rarely occurs before 5 to 7 years after surgery. If the stem cracks but does not displace, the patient will have pain at the site of fracture, but the radiographs will remain negative until enough motion exists to cause displacement of the metal fracture pieces. Pain is significant and the patient will seek ambulatory aids. The older casted stems tended to break about 2 cm proximal to the forged junction with the body.

Disassociation of Morse Tapers Disassociation of the Morse taper locking mechanism is exceedingly rare and most likely due to failure to impact the components adequately. Surgical exploration and reassembly of the components and full impaction are required.

Aseptic Loosening The incidence of aseptic loosening of the femoral stems has been reduced by the incorporation of extramedullary porous ingrowth beads at the junction of the segmental replacement and the stems. Soft tissue ingrowth into these beads in the diaphysis isolates the joint debris from the bone-cement-prosthesis composite, creating a “biologic purse-string” effect.11 Hydroxyapatite coatings can also enhance fixation.8 Cross-pin stem fixation requires a custom component but permits the use of a short stem or a metaphyseal position that would normally lead to early aseptic loosening.2 On rare occasions, patients develop a polyethylene debris synovitis. Exploration of the reconstruction, resection of the “pseudosynovium” or periprosthetic capsule, and exchange of the bushings and extensor stop can manage this. JE never revises the all-polyethylene tibia or polyethylene patellar components if they are well cemented unless there is an infection. If the cemented tibial polyethylene is removed, then at reconstruction, a metal-backed tibial component is used. Recementing an all-polyethylene tibial component in revision situations risks early aseptic loosening as the cementation is never as good as the primary reconstruction.

REFERENCES 1. Bickels J, Wittig JC, Kollender Y, et al. Distal femur resection with endoprosthetic reconstruction: a longterm followup study. Clin Orthop Relat Res 2002;400:225-235. 2. Cannon CP, Eckardt JJ, Kabo JM, et al. Cross-pin fixation in 32 tumor endoprosthetic stems. Clin Orthop Relat Res 2003;417:285-292. 3. Eckardt JJ, Kabo JM, Kelly CK, et al. Endoprosthetic reconstruction for bone metastasis. Clin Orthop Relat Res 2003;415(suppl): S254-S262. 4. Eckardt JJ, Lesavoy MA, Dubrow TJ, et al. Exposed endoprosthesis: management protocol using muscle and myocutaneous flaps. Clin Orthop Relat Res 1990;251:220-229. 5. Freedman EL, Hack DJ, Johnson EE, et al. Total knee replacement including a nodular distal femoral component in elderly patients with acute fractures and nonunion. J Orthop Trauma 1995;9:231-237. 6. Freidman EH, Eckardt JJ. A modular endoprosthetic system for tumor and non-tumor reconstructions: preliminary report. Orthopaedics 1996;20:20-27. 7. Kabo JM, Yang RS, Dorey FJ, et al. In vivo rotational stability in the kinematic rotating hinge knee. Clin Orthop Relat Res 1997;336: 166-176. 8. Kay RM, Kabo JM, Seeger LL, et al. Hydroxyapatite-coated distal femoral replacements: preliminary results. Clin Orthop Relat Res 1994;302:92-100. 9. Ward WG, Eckardt JJ. Endoprosthetic reconstruction of the femur following massive bone reconstruction. J South Orthop Assoc 1994;3: 108-116.

10. Ward WG, Haight D, Ritchie P, et al. Dislocation of rotating total knee arthroplasty: a biomechanical analysis. J Bone Joint Surg Am 2003;85A:448-453. 11. Ward WG, Johnston KS, Dorey FJ, et al. Extramedullary porous coating to prevent diaphyseal osteolysis and lines around proximal tibial replacements. J Bone Joint Surg Am 1993;75A:976-987. 12. Ward WG, Johnson KS, Dorey FJ, et al. Loosening of massive femoral cemented endoprostheses. J Arthroplasty 1997;12:741-750. 13. Wirganowicz PZ, Eckardt JJ, Dorey FJ, et al. Etiology and results of tumor endoprosthesis revision surgery in 64 patients. Clin Orthop Relat Res 1999;358:64-74. 14. Wu CC, Pritsch T, Shehadeh A, et al. The anterior popliteal approach for popliteal exploration, distal femoral resections, and endoprosthetic reconstruction. J Arthroplasty 2008;23:254-262.

Chapter 26 Proximal Tibia Resection with Endoprosthetic Reconstruction Jacob Bickels Martin M. Malawer

BACKGROUND Resection of the proximal tibia includes the removal of one-half to two-thirds of the tibia along with a portion of all muscles that insert on it as well as the entire popliteus muscle, in combination with an extra-articular resection of the proximal tibiofibular joint. The peroneal nerve is preserved. Of all anatomic locations in which major bone resections and prosthetic reconstructions are done, the proximal tibia is considered to be the site in which surgery is the most complicated, where rates of complications are highest, and whose functional outcome is poorest. The major contributors to these complications include the lack of muscle coverage along the anteromedial aspect of the tibia, the relatively small caliber of the blood vessels around the leg, and the need to include the insertion site of the extensor mechanism with the removed surgical specimen. In the past, these difficulties made it impossible to perform limb-sparing surgery, and above-knee amputations were the only surgical option for malignant tumors at this site. The limb-sparing technique illustrated in this chapter allows a safe approach to the dissection of popliteal vessels and to the resection and replacement of the proximal one-third to two-thirds of the tibia. Preoperative evaluation of tumor extent requires a detailed understanding of the anatomy and careful evaluation by computed tomography (CT), magnetic resonance (MR) imaging, bone scintigraphy, and biplane angiography. Types of possible reconstructions include primary arthrodesis, prosthetic replacement, and allograft replacement. We prefer the prosthetic replacements because of the high rates of nonunion and infections associated with allograft reconstruction and the poor function of an arthrodesed knee. The use of a gastrocnemius rotational flap is a key factor in achieving adequate soft tissue coverage of the prosthesis and in restoring function of the extensor mechanism.

ANATOMY Knee Joint and Cruciate Ligaments The knee joint is seldom directly invaded by tumors of the proximal tibia. When it does occur, invasion is usually the result of a pathologic fracture, contamination of an improper biopsy technique, or tumor extension along the cruciate ligaments. The presence of hemarthrosis is suggestive of intra-articular disease. Involvement of the cruciate ligaments is often not determined until the time of surgery, although an MR imaging scan is a reliable means of determining cruciate ligament involvement preoperatively. An extra-articular resection (ie, en bloc resection of the proximal tibia, joint capsule, and femoral condyles) should be considered if nodules are identified on the cruciate ligaments.

Extensor Mechanism The attachment site of the extensor mechanism at the tibial tuberosity is resected en bloc with the proximal tibia. Reconstruction of this mechanism is essential for a functioning extremity.

Popliteal Trifurcation The popliteal artery divides into the anterior tibial artery, the posterior tibial artery, and the peroneal artery at the inferior border of the popliteus muscle. The popliteal trifurcation is actually composed of two bifurcations. The first is found where the anterior tibial artery arises from the popliteal artery, which then continues as the tibioperoneal trunk. The anterior tibial artery is the first branch and arises at the inferior border of the popliteus muscle. The second bifurcation is found where the peroneal artery and the posterior tibial artery arise from the tibioperoneal trunk; thus, this bifurcation is distal to the anterior tibial artery. It is almost always necessary to ligate the anterior tibial artery at the time of resection, whereas the other vessels must be identified before ligation. A unique and fortuitous anatomic feature is that the popliteus muscle covers the posterior surface of the tibia, which affords an excellent boundary between the posterior soft tissue extension from the tibia and the neurovascular bundle of the lower extremity. This is in contrast to what occurs at the distal femur in which the posterior aspect is covered solely by the popliteal fat.

Tibiofibular Joint The proximal tibiofibular joint is located close to the posterolateral aspect of the proximal tibia. Histologic studies show that tumors involving the proximal tibia have a high incidence of extension and involvement of the periscapular tissues of the tibiofibular joint. To obtain a satisfactory surgical margin while performing a resection of the proximal tumor, it is necessary to remove this joint en bloc, that is, perform an extra-articular resection. This is routine procedure for all highgrade sarcomas of the proximal tibia.

Subcutaneous Location of the Tibia The entire medial aspect of the tibia lies in a subcutaneous location and remains there after resection and reconstruction approaches had been carried out. This had been a major source of primary and secondary infections, which, in turn, frequently necessitated above-knee amputation. P.309

FIG 1 • A. Anteroposterior and (B) lateral plain radiographs showing osteosarcoma of the proximal tibia in a 17-year-old female patient. Following treatment with neoadjuvant chemotherapy, this patient was referred to proximal tibia resection with endoprosthetic reconstruction. Today, the routine transfer of the medial gastrocnemius muscle anteriorly to cover the prosthesis is considered a reliable method of prosthetic coverage. It also provides a method of extensor mechanism reconstruction. It is a simple and reliable means of decreasing the incidence of infection, flap necrosis, and secondary amputation.4

INDICATIONS AND CONTRAINDICATIONS Primary bone sarcomas of the proximal tibia (FIG 1) Benign aggressive tumors associated with extensive bone destruction (FIG 2) Metastatic tumors associated with extensive bone destruction The major contraindications to limb sparing are neurovascular involvement and compromise as well as extensive soft tissue tumor involvement that precludes adequate prosthetic coverage.

IMAGING AND OTHER STAGING STUDIES Computed Tomography and Magnetic Resonance Imaging CT and MR imaging are useful to determine the extent of cortical destruction and intramedullary and soft tissue extensions of the primary tumor. These data are essential for determining the level of tibial resection, which is 3 to 5 cm distal to the area of intramedullary tumor involvement. MR imaging can also reveal skip lesions, which may affect the extent of tibial resection (FIGS 3 and 4).

FIG 2 • A. Anteroposterior plain radiograph showing giant cell tumor of the proximal tibia in a 48-year-old female patient. This radiograph was done for persistent knee pain and this large lesion, which filled the metaepiphyseal regions, was missed by the physician who initially interpreted the film. B. Anteroposterior and lateral plain radiographs (C) were taken again 5 months later because of additional symptoms. This time, there was evidence of overwhelming extensive bone destruction. (continued) P.310

FIG 2 • (continued) D. Axial CT showing tumor filling the entire metaphysis of the proximal tibia with thinning and ballooning of the cortices. The patient was treated with proximal tibia endoprosthetic reconstruction. E. A sagittal cut through the surgical specimen shows the large tumoral mass and the cortical destruction.

FIG 3 • A,B. Anteroposterior and lateral plain radiographs, CT (C), and MR imaging (D) showing osteosarcoma of the proximal tibia. These studies demonstrate that the tumor is associated with minimal destruction of the cortices and that there is no soft tissue extension. The MR scan also accurately depicts the distal point of the intramedullary tumor extension. These findings will assist in determining the osteotomy level and the amount of surrounding soft tissue to be resected en bloc with the tumor. P.311

FIG 4 • Anteroposterior plain radiograph (A) and CT (B) showing osteosarcoma of the proximal tibia with cortical destruction and soft tissue extension of the tumor.

Angiography Biplane angiography (FIG 5) is used for local arterial evaluation, especially if CT has revealed posterior soft tissue extension. The anteroposterior view is used to evaluate the popliteal bifurcation; of particular relevance is the integrity of the posterior tibial artery, which may be the sole blood supply to the leg after resection. The lateral view is essential for evaluating the interval between the tibia and the neurovascular bundle. For example, the popliteus muscle often separates a posterior tumor mass from the vessels. This is reflected as a clear interval on the lateral angiogram and serves as an indication that there is an adequate resection margin. Ligation of the anterior tibial artery is almost always required. The peroneal artery may be involved by tumors that have a large posterior compartment. Two of the major vessels may be ligated in a young patient, without jeopardizing the possibility of a viable and functional extremity. The posterior tibial artery is almost never involved by tumor.

SURGICAL MANAGEMENT There are three major steps involved in successful resection and reconstruction of tumors of the proximal tibia: Resection of the tumor Prosthetic reconstruction of the skeletal defect and knee joint Reconstruction of the extensor mechanism and soft tissue coverage of the prosthesis with a gastrocnemius

flap1,3

FIG 5 • An angiogram showing a lateral view of the popliteal artery. The space between the tumor in the proximal tibia and the popliteal bifurcation is best visualized by this study. The popliteal artery (P), tibioperoneal trunk (TP), and anterior tibia (AT) arteries are all identifiable. It is essential that the soft tissue posterior to the tumor mass (curved arrow) be free of cancer along the popliteal artery and tibioperoneal trunk. The popliteus muscle covers the bone in this interval and usually protects the vessels from tumor invasion. A tumor (T) blush (small arrows) is seen anteriorly. (From Malawer MM, McHale KA. Limb-sparing surgery for high-grade malignant tumors of the proximal tibia: surgical technique and a method of extensor mechanism reconstruction. Clin Orthop Relat Res 1989;239:231-248.) P.312

TECHNIQUES ▪ Exposure

A single anteromedial incision is made, beginning proximally at the distal one-third of the femur and continuing to the distal one-third of the tibia (TECH FIG 1).

TECH FIG 1 • Illustration (A) and operative photograph (B) showing the anteromedial incision used for exposure of the proximal tibia and neurovascular bundle. It begins at the distal one-third of the femur and continues to the distal one-third of the tibia and includes excision of the biopsy site, which remains attached to the underlying bone. C. Thick fasciocutaneous flaps are developed. (A: From Malawer MM, McHale KA. Limb-sparing surgery for high-grade malignant tumors of the proximal tibia: surgical technique and a method of extensor mechanism reconstruction. Clin Orthop Relat Res 1989;239:231248.) The approach includes excision of biopsy sites with a margin of at least 2 cm. Medial and lateral thick flaps of skin and subcutaneous tissue including the fascia are developed to decrease the likelihood of flap ischemia.

▪ Exploration of the Popliteal Fossa and Vascular Bundle The popliteal trifurcation must be explored early to determine whether the tumor is operable, especially if its soft tissue component extends posteriorly. If it does not, the popliteal space and trifurcation are exposed by detaching the medial gastrocnemius muscle and by splitting the soleus muscle (TECH FIG 2). The popliteal artery can be easily identified and it can be traced distally around the popliteus muscle. Care must be taken to identify and protect all major vascular branches.

TECH FIG 2 • Illustration (A) and operative photograph (B) showing exploration of popliteal artery trifurcation, which is required to determine the feasibility and extent of the feasibility of resectability. The medial flap is continued posteriorly, and the medial hamstrings are released at 2 to 3 cm proximal to their insertion to expose the popliteal fossa. The popliteal vessels are identified, and the trifurcation is initially explored through the medial approach. The medial gastrocnemius is partially mobilized, and the soleus muscle is split to expose the neurovascular structures. Care is taken to preserve the medial sural artery, which is the main pedicle to the medial gastrocnemius muscle. If the interval between the posterior aspect of the tibia and the tibioperoneal trunk (separated by the popliteus muscle) is free of tumor, resection can proceed. (continued) P.313

TECH FIG 2 • (continued) C. Dissection and exposure of the neurovascular bundle is often difficult because the tumor has distorted the normal anatomy. It requires splitting of the soleus muscle for most of its length. Care should be taken to identify and protect all major vascular branches prior to any ligation. The anterior tibial artery, which is the first of the popliteal artery, is located at the inferior border of the popliteus muscle. As it passes directly anterior through the interosseous membrane, it tethers the entire neurovascular bundle. (A,C: From Malawer MM, McHale KA. Limb-sparing surgery for high-grade malignant tumors of the proximal tibia: surgical technique and a method of extensor mechanism reconstruction. Clin Orthop Relat Res 1989;239:231-248.)

▪ Detachment of Vascular Bundle Applying posterior traction proximal to the popliteal artery permits visualization of the takeoff of the anterior tibial artery and its accompanying veins. The anterior tibial vessels are individually ligated, allowing the entire neurovascular bundle to fall away from the posterior aspect of the tibia and/or tumor (TECH FIG 3).

TECH FIG 3 • Ligation of the anterior tibial vessels allows the entire neurovascular bundle to fall away from the posterior aspect of the tibia. (From Malawer MM, McHale KA. Limb-sparing surgery for highgrade malignant tumors of the proximal tibia: surgical technique and a method of extensor mechanism reconstruction. Clin Orthop Relat Res 1989;239:231-248.) If the mass is a large one, there is a possibility that the peroneal artery must be ligated as well, leaving the posterior tibial artery as the single blood supply to the leg. Further posterior mobilization of the popliteal vessels is achieved by ligation of the inferior geniculate vessels. P.314

▪ Exposure of the Knee Joint Removal of the Proximal Tibia The capsule is transected circumferentially approximately 1 cm away from the tibia and the patellar tendon to avoid contamination (TECH FIG 4). The cruciate ligaments are carefully examined; if there is any evidence of tumor invasion into the joint space, the femoral condyles are later resected en bloc with the proximal tibia. The patellar tendon is sectioned 1 to 2 cm proximal to the tibial tubercle, and the entire capsule of the knee is detached circumferentially by electrocautery 1 to 2 cm from the tibial insertion.

TECH FIG 4 • Illustration (A) and operative photograph (B) showing circumferential detachment of the joint capsule 1 cm away from the tibia and the patellar tendon. (A: From Malawer MM, McHale KA. Limbsparing surgery for high-grade malignant tumors of the proximal tibia: surgical technique and a method of extensor mechanism reconstruction. Clin Orthop Relat Res 1989;239:231-248.)

TECH FIG 5 • A. Illustration and (B) operative photograph showing osteotomy of the proximal tibia 3 to 5 cm distal to the lesion. The intermuscular septum is released, after which an intra-articular resection of the knee joint is completed. (A: From Malawer MM, McHale KA. Limb-sparing surgery for high-grade malignant tumors of the proximal tibia: surgical technique and a method of extensor mechanism reconstruction. Clin Orthop Relat Res 1989;239:231-248.) The posterior capsule is carefully dissected under direct vision after the popliteal vessels have been mobilized by ligation of the inferior geniculate vessels. The cruciate ligaments are then sectioned close to the femoral attachments. To release the specimen, the tibia is osteomized 3 to 5 cm distal to the lesion, as determined by CT and MR imaging (TECH FIG 5). The intermuscular septum is released under direct vision. An intra-articular resection of the knee joint is then completed. P.315

▪ Prosthetic Reconstruction Design features of currently used proximal tibia prostheses include modular components with an anterior metal loop for the attachment of the patellar tendon, porous coating for soft tissue incorporation, side holes for securing adjacent muscles, and a rotating hinge knee mechanism (TECH FIG 6).

TECH FIG 6 • A-E. Current design features of proximal tibia endoprostheses include modular components with an anterior metal loop for the attachment of the patellar tendon, porous coating for soft tissue incorporation, side holes for securing adjacent muscles, and a rotating hinge knee mechanism. Uncemented prostheses are preferentially used for reconstruction after resection of a primary bone sarcoma in an adolescent or a young adult, whereas cemented prostheses are used for reconstruction after resection of metastatic tumors.

▪ Reconstruction of the Extensor Mechanism and Medial Gastrocnemius Flap The remaining patellar tendon stump is advanced distally and secured tightly to the prosthesis with a 3mm Dacron tape (Deknatel, Falls River, MA) that provides immediate mechanical fixation. An autologous bone graft, taken from the cut femoral condyles, is wedged and packed tightly between the porous-coated segment of the prosthesis and the tendon, facing both surfaces (TECH FIG 7). This will recreate a new “bone-tendon” junction. The soleus muscle is pulled anteriorly to cover the middle segment of the prosthesis, and the medial gastrocnemius is used to cover its proximal segment (TECH FIG 8). The medial

P.316 gastrocnemius muscle is detached at its muscle-tendon junction and interface with the lateral gastrocnemius, mobilized and rotated anteriorly to cover the prosthesis. At its upper pole, the muscle flap is sutured to the patellar tendon to reinforce the prosthesis and bone graft reconstruction.

TECH FIG 7 • A. Illustration showing reconstruction of the extensor mechanism, which has three components: attachment of the patellar tendon to the prosthesis, reinforcement of the attachment site with bone graft, and overlying medial gastrocnemius flap. B. Intraoperative photograph showing the patellar tendon sutured to the prosthesis and underlying bone graft. C-F. Alternatively, a circumferential polyethylene terephthalate (Trevira; Implantcast Gmbh, Buxtehude, Germany) tube may be applied on the prosthesis to which the patellar tendon and surrounding muscles can be sutured.2 ( A: From Malawer M. Proximal tibial resection with endoprosthetic reconstruction. In: Malawer MM, Sugarbaker PH, eds. Musculoskeletal Cancer Surgery: Treatment of Sarcomas and Allied Diseases. Dordrecht: Kluwer Academic Publishers, 2001:485-504.) Suction drains are positioned along the muscle envelope, and the fasciocutaneous flaps are pulled and

closed, usually leaving a gap over the medial gastrocnemius flap, which necessitates coverage with a split-thickness skin graft taken from the ipsilateral thigh (TECH FIG 9). P.317

TECH FIG 8 • Illustrations (A-C) and intraoperative photographs (continued) P.318

TECH FIG 8 • (continued) (D-F) showing soft tissue coverage around the prosthesis. The soleus muscle is pulled anteriorly to cover the middle segment of the prosthesis, and the medial gastrocnemius is transposed to cover its proximal segment. The medial sural artery to the medial gastrocnemius muscle is carefully preserved. The medial gastrocnemius muscle is detached at its muscle-tendon junction and interfaced with the lateral gastrocnemius, mobilized and rotated anteriorly to cover the prosthesis. It is sutured to the border of the anterior muscles and the patellar tendon, forming a complete soft tissue envelope around the prosthesis. (A,B: From Malawer MM, McHale KA. Limb-sparing surgery for highgrade malignant tumors of the proximal tibia: surgical technique and a method of extensor mechanism reconstruction. Clin Orthop Relat Res 1989;239:231-248; C: From Malawer M. Proximal tibial resection with endoprosthetic reconstruction. In: Malawer MM, Sugarbaker PH, eds. Musculoskeletal Cancer Surgery: Treatment of Sarcomas and Allied Diseases. Dordrecht: Kluwer Academic Publishers, 2001:485-504.)

TECH FIG 9 • A-E. Suction drains are positioned along the muscle envelope, and the fasciocutaneous flaps are pulled and closed, usually leaving a gap over the medial gastrocnemius flap, which necessitates coverage with a split-thickness skin graft, taken from the ipsilateral thigh. (continued) P.319

TECH FIG 9 • (continued) Anteroposterior (F) and lateral plain radiographs (G) showing a proximal tibia endoprosthetic reconstruction.

PEARLS AND PITFALLS Surgical considerations

▪ Long anteromedial incision ▪ Ligation of the anterior tibial artery allows retraction of the vascular bundle away from the proximal tibia and enables safe resection.

Reconstruction

▪ Reconstruction of the proximal tibial defect with uncemented prostheses for primary bone sarcomas in young adults and cemented prostheses for metastatic lesions ▪ Reconstruction of the extensor mechanism composed of three components: attachment of the patellar tendon stump to the prosthesis, reinforcement with a bone graft, and overlaying of a medial gastrocnemius flap. ▪ Viable soft tissue coverage of the entire length of the prosthesis: the soleus muscle for its middle third and medial gastrocnemius or its proximal third

Rehabilitation

▪ Prolonged immobilization of the operated extremity in full extension followed by gradual range-of-motion exercises are

essential for restoring function of the extensor mechanism.

POSTOPERATIVE CARE The extremity is kept elevated and in full extension to avoid tension on the reconstructed patellar tendon for 5 days. Continuous suction is required for 3 to 5 days, and perioperative intravenous antibiotics are continued until the drainage tubes are removed. If there is no evidence of significant swelling by the end of the fifth day, the patient is allowed to walk with weight bearing as tolerated for 10 to 15 minutes at a time. If the extremity remains free of swelling, a gradual increment in exercise is allowed. The knee is kept fully extended in a knee immobilizer for 6 weeks, by the end of which gradual passive and active flexion of the knee joint are allowed.

OUTCOMES Proximal tibia resections are associated with considerably higher rates of flap ischemia, deep infection, and prosthetic loosening than limb-sparing resections at other sites, such as the proximal humerus and the proximal and distal aspects of the femur. P.320 The lower survival data for prosthetic replacements at the lower tibia (80% at 10 years compared with 95% for the others) are most likely attributable to the complexity of the surgical procedure and the soft tissue reconstruction, breakage of the polyethylene component, and mechanical failure. In addition, impairment of the extensor mechanism is still the most prominent functional compromise after this resection. The incidence of infection has been dramatically decreased by the use of a gastrocnemius muscle flap. Strict adherence to postoperative management guidelines has also decreased the incidence of limb edema, wound problems, and magnitude of extensor mechanism dysfunction.

COMPLICATIONS Limb edema Flap ischemia to full-thickness necrosis Deep periprosthetic infection Dysfunctional extensor mechanism and extension lag Prosthetic loosening

REFERENCES 1. Bickels J, Wittig JC, Kollender Y, et al. Reconstruction of the extensor mechanism after proximal tibia endoprosthetic replacement. J Arthroplasty 2001;16:856-862. 2. Gosheger G, Hillmann A, Lindner N, et al. Soft-tissue reconstruction of megaprostheses using a trevira tube. Clin Orthop Relat Res 2001;393:264-271. 3. Malawer MM, McHale KA. Limb-sparing surgery for high-grade malignant tumors of the proximal tibia:

surgical technique and a method of extensor mechanism reconstruction. Clin Orthop Relat Res 1989;231:231-248. 4. Malawer MM, Price WM. Gastrocnemius transposition flap in conjunction with limb-sparing surgery for primary bone sarcomas around the knee. Plast Reconstr Surg 1984;73:741-750.

Chapter 27 Fibular Resections Jacob Bickels Kristen Kellar-Graney Martin M. Malawer

BACKGROUND The fibula is a rare anatomic location for both primary and metastatic bone tumors.1 When tumor does occur, it most commonly involves the proximal fibula, followed by the fibular diaphysis and the distal fibula. Chondrosarcoma, osteosarcoma, and benign aggressive cysts constitute the most common histologic subtypes of fibular tumors (Table 1). Primary bone sarcomas of the fibula have traditionally been treated with above-knee amputations. Increased use of limbsparing procedures stimulated an interest in the surgical anatomy in this area and the possibility that tumors of the fibula might be safely resected.2,3,4,5,6,7

ANATOMY Proximal Fibula The proximal fibula is the attachment site for the lateral collateral ligament (LCL) and biceps femoris tendon and therefore has a role in determining lateral knee joint stability. The peroneal nerve turns around the base of the fibular head to enter the peroneus longus tunnel (FIG 1).

Fibular Diaphysis The fibular diaphysis is circumferentially surrounded by muscle origins at all aspects and anatomic levels.

Distal Fibula The distal fibula is a subcutaneous structure with minimal soft tissue coverage.

Table 1 Tumors of the Proximal Fibula by Histologic Subtype, 1990-2014 Tumor

No.

Benign aggressive cysts (GCTs and ABCs)

18

Chondrosarcoma

16

Osteosarcoma

5

Ewing sarcoma

7

Osteochondroma

11

Enchondroma

9

Other

10

Metastatic carcinomas to bone

2

Total

78

It is the attachment site for the tibiofibular and calcaneofibular ligaments and therefore has a role in determining lateral ankle joint stability.

INDICATIONS Benign aggressive tumors Primary sarcomas of bone

FIG 1 • A. The LCL and biceps femoris tendon attach to the fibular head, and the peroneal nerve turns around the base of the fibula to enter the peroneus longus tunnel. B. Intraoperative photograph showing the peroneal nerve (N) as it enters the peroneus longus tunnel (open arrow). This tunnel has been opened to show the course of the nerve around the base of the fibular head. The biceps tendon (Bi ) inserts on the fibular head away from the peroneal nerve. Vessel loops on the peroneal nerve are used to provide gentle traction for the dissection of the nerve branches. P.322

FIG 2 • A. Computed axial tomography of the proximal fibula shows an intermediate-grade fibrosarcoma with cortical breakthrough and extraosseous extension. B,C. Coronal and axial magnetic resonance images of the proximal fibula, respectively, showing a high-grade osteosarcoma with cortical breakthrough and extension to the anterior and lateral compartments of the leg. (Courtesy of Martin M. Malawer.) Metastatic lesions of the fibula are usually treated with radiation therapy and rarely require surgery. This is because the fibula is not a major weight-bearing structure and bone destruction at that site does not compromise the mechanical stability of the lower extremity. Above-knee amputation is considered when a malignant tumor grossly invades the tibia or there is extensive multicompartmental involvement, especially the posterior deep compartment.

IMAGING AND OTHER STAGING STUDIES In staging fibular tumors, emphasis is placed on the extent of bone destruction, intramedullary involvement, and soft tissue extension. Special attention is also given to the relation of the tumor to the peroneal nerve, blood vessels, and tibia. Plain radiographs and computed tomography are required to assess the extent of bone involvement and cortical destruction. These data are completed by magnetic resonance imaging (MRI), which shows the extent of medullary and extraosseous extension (FIG 2).

SURGICAL MANAGEMENT Positioning A semisupine position (45-degree elevation of the operated side) is used to permit easy access to the anterior and lateral compartments and allow dissection of the popliteal space. The entire extremity, from the inguinal

ligament to the foot, is included in the sterile field to allow evaluation of the distal foot pulses and execution of an above-knee amputation, if indicated. The utilitarian fibular incision, which allows exposure and resection of tumors at all levels of the fibula, extends from the biceps above the knee joint, over the midportion of the fibula, anteriorly to the crest of the tibia, and then curves posteriorly and distally to the ankle. This permits the development of large anterior and posterior fasciocutaneous flaps. The anterior compartment, the lateral compartment (peroneal musculature), and the superficial posterior compartment consisting of the lateral gastrocnemius and soleus muscle are exposed, and the popliteal space and trifurcation can be explored through this incision. The biopsy site is removed en bloc with the tumor mass (FIG 3).

FIG 3 • A. The utilitarian fibular incision extends from the biceps above the knee joint, over the midportion of the fibula, and anteriorly to the crest of the tibia, and then curves posteriorly and distally to the ankle. A component of the incision is used according to the level of resection: The proximal third is used for resection of the proximal fibula (B) and the proximal two-thirds are used for intercalary resection (C). (A: From Malawer MM. Surgical management of aggressive and malignant tumors of the proximal fibula. Clin Orthop Relat Res 1984;186:172181.) (continued) P.323

FIG 3 • (continued)

TECHNIQUES ▪ Proximal Fibula Resection Three types of tumor resections are practiced around the proximal fibula: curettage and type I and II resections of the proximal fibula. Tumor curettage is done in benign aggressive tumors and lowgrade sarcomas associated with minimal cortical destruction and extraosseous extension (TECH FIG 1A). The types of proximal fibular resections have been previously described by Malawer.5 Type I resection includes the proximal fibula, a thin muscle cuff in all dimensions, and the LCL attachment site. The peroneal nerve and its motor branches are preserved and the tibiofibular joint is excised intraarticularly (TECH FIG 1B-D).5 This resection type is used for the management of benign aggressive tumors and low-grade sarcomas that have caused considerable cortical destruction of the proximal fibula. Type II resection includes an en bloc removal of the proximal fibula and the tibiofibular joint, the anterior and lateral muscle compartments, the peroneal nerve, and the anterior tibial artery (TECH FIG 1E-H). It is used for the management of high-grade sarcomas, which usually have considerable cortical destruction with extraosseous extension. All type II resections necessitate anterior tibial artery ligation: In contrast, type I resections usually allow preservation of that artery. A type II resection may also require sacrifice of the peroneal artery. Table 2 summarizes the anatomic structures removed en bloc with the various resection types of the proximal fibula. Exposure Curettage The common peroneal nerve is identified around the inferior border of the biceps femoris. If the nerve is

to be preserved, as in tumor curettage or type I resection, its course under the peroneus longus is identified, the peroneus longus tunnel is unroofed, and the nerve is mobilized posteriorly away from the proximal fibula and marked with a vessel loop (TECH FIG 2). A longitudinal cortical window with oval edges is made above the lesion. Type I and II Resections Large tumors of the proximal fibula may reach the midline posteriorly and push and distort the popliteal vessels. The major vessels are exposed by reflecting the lateral gastrocnemius muscle through its length and, if necessary, releasing the proximal tendinous origin from the lateral femoral condyle. This exposes the underlying soleus muscle, which is similarly detached through its substance near its fibular origin.

TECH FIG 1 • A. Low-grade chondrosarcoma of the proximal fibula with expanded but intact cortices with no extraosseous tumor extension. This tumor is managed with curettage and high-speed burr drilling. B,C. Anteroposterior (AP) and lateral plain radiographs showing aneurysmal bone cyst of the proximal fibula. (continued) P.324

TECH FIG 1 • (continued) D. This type of benign aggressive tumor is managed with a type I resection, which includes the proximal fibula, a thin muscle cuff in all dimensions, and the LCL attachment site. E,F. AP and lateral plain radiographs showing high-grade osteosarcoma of the proximal fibula. G. This type of high-grade sarcoma of bone is managed with a type II resection, which includes an en bloc removal of the proximal fibula and the tibiofibular joint, the anterior and lateral muscle compartments, the peroneal nerve, and the anterior tibial artery. H. Cross-sectional anatomy of the proximal leg showing type I and type II resections. (H: Courtesy of Martin M. Malawer.)

Table 2 Anatomic Structures Removed with the Various Resection Types of the Proximal Fibula Type of Surgery

Lateral Collateral Ligament Attachment Site

Anterior Tibial Artery

Peroneal Nerve

Curettage

Intact

Intact

Intact

Type I resection

Removed

Intact

Intact

Type II resection

Removed

Removed

Removed

The neurovascular bundle can be easily identified at the level of the popliteus muscle: The anterior tibial artery is positioned 2 to 3 cm distal to its inferior border. The peroneal artery lies close to the posterior aspect of the tibia and along the flexor hallucis longus muscle. The posterior tibial nerve is closest to the surface, and the popliteal veins course between the nerve and the posterior tibial artery, which can be identified in the midline. The interval between the posterior fibular head and the posterior tibial and popliteal arteries must be explored and evaluated early to determine whether a high-grade sarcoma is resectable or a vascular graft will be required. The anterior tibial artery passes directly anteriorly through the interosseous septum, tying down the vascular complex and preventing mobilization. Applying traction on the popliteal artery, a simple maneuver, permits visualization of the anterior tibial artery P.325 origin. The anterior tibial artery and the two accompanying veins may then be ligated and transected, allowing the popliteal and posterior tibial arteries to fall away from the posterior surface of the mass. Completion of the vascular dissection proceeds distally.

TECH FIG 2 • A. Exposure of the compartment following development of fasciocutaneous flaps. B. The common peroneal nerve is identified around the inferior border of the biceps femoris. The peroneus longus tunnel is unroofed to expose the nerve coursing around the fibular diaphysis. Tumor Removal Curettage Gross tumor is removed with hand curettes (TECH FIG 3A,B). Curettage should be meticulous and should leave only microscopic disease in the tumor cavity. Curettage is followed by high-speed burr drilling of the walls of the tumor cavity (TECH FIG 3C,D). Type I Resection The LCL and biceps tendon are released at their fibular insertion. Muscle origin is transected by electrocauterization from the proximal shaft of the fibula. The anterior tibiofibular capsule can then be identified: Its posterior aspect lies under the popliteus muscle.

The capsule is incised and the joint opened, after which an intra-articular resection of the proximal fibula is carried out by performing an osteotomy 1 cm below the lower edge of the lesion (TECH FIG 3E). Type II Resection The anterior and lateral musculature and the overlying deep fascia are excised. The origin of the anterior muscles from the shaft of the tibia is transected by electrocauterization. The distal level of the transection is at the musculotendinous junction. The LCL, biceps tendon, and peroneal nerve are released 2.5 cm proximal to their fibular insertion. The anterior tibiofibular capsule can then be identified (TECH FIG 3F). A semicircular cut is made directly through the popliteus muscle toward the posterior aspect of the lateral tibial condyle. A fibular osteotomy is done 2 to 3 cm below the lower edge of the tumor (TECH FIG 3G). It is important to inspect the condyle after osteotomy and removal of the specimen. If the knee joint capsule P.326 P.327 had been exposed and opened, it should be repaired to prevent a synovial fistula.

TECH FIG 3 • A. Macroscopic tumor is removed with hand curettes. B. Curettage of low-grade chondrosarcoma of the proximal fibula. (continued)

TECH FIG 3 • (continued) C,D. Curettage is followed with high-speed burr drilling of the walls of the tumor cavity. E. Type I resection of the proximal fibula. The tibiofibular joint is opened, the peroneal longus tunnel is unroofed to expose the peroneal nerve, muscle origins are transected from the proximal shaft of the fibula, and an osteotomy is performed 1 cm below the lower edge of the lesion. F. Further dissection reveals the musculocutaneous and motor branches of the peroneal nerve. G. Type II fibular resection. The resection of the proximal fibula begins with exploration of the popliteal trifurcation posteriorly. The anterior tibial artery and often the peroneal vessels are ligated if there is a large posterior component to the tumor. A resection then proceeds, with release of all of the muscles attaching to the fibula posteriorly and preservation of the tibial nerve. The peroneal nerve is ligated before it enters the peroneus longus muscles. All of the tibialis muscles are released from the tibial border and are retained on the specimen side. The final step is an extra-articular disarticulation of the tibiofibular joint with a curved osteotome or a high-speed burr drill, removing a portion of the lateral tibial plateau with the joint en bloc. Care must be taken to avoid entering the knee joint. (F: From Malawer MM. Surgical management of aggressive and malignant tumors of the proximal fibula. Clin Orthop Relat Res 1984;186:172-181.) Reconstruction and Wound Closure

Curettage The tumor cavity is filled with bone graft or a bone substitute for benign aggressive lesions in a young patient. Cement is used for reconstruction in adults, especially in low-grade sarcomas or metastatic lesions. Type I and II Resections The LCL stump is attached to the lateral tibial metaphysis using a staple with the knee in 20 degrees of flexion after an osteoperiosteal flap has been formed (TECH FIG 4A-D). Fixation is reinforced with nonabsorbable sutures to the overlying iliotibial band and fascia. When the surgical field extends to the lower leg, the authors pull up the peronei and extensor digitorum longus tendons, thereby advancing the foot to a neutral position (to reduce the magnitude of foot drop and possibly avoid the need for an ankle-foot orthosis), and then tenodese the tendons to the tibial shaft using a 3-mm Dacron tape (TECH FIG 4E,F). The surgical defect is closed by rotating the lateral gastrocnemius muscle anteriorly to the deep fascia, covering the exposed tibia. The gastrocnemius muscle is sutured to the deep fascia and to the soleus muscle distally as well as along the lateral capsule of the knee joint. The biceps tendon is then tenodesed to the gastrocnemius muscle (TECH FIG 4G).

TECH FIG 4 • A-D. The stump of the LCL is attached to the lateral tibial metaphysis using a staple with the knee in 20 degrees of flexion after an osteoperiosteal flap has been raised. (continued) P.328

TECH FIG 4 • (continued) E. Surgical defect after a type II resection, which usually is associated with a foot drop because of the need to resect the peroneal nerve. F. Tenodesis of the peronei and the extensor tendons to the tibial shaft with the foot in neutral position may prevent plantarflexion and obviate the need for an ankle-foot orthosis. G. After resection of the fibula, the surgical defect is closed by rotating the lateral gastrocnemius muscle anteriorly to the deep fascia, covering the exposed tibia. The gastrocnemius muscle is sutured to the deep fascia and to the soleus muscle distally as well as along the lateral capsule of the knee joint. The biceps tendon is then tenodesed to the gastrocnemius muscle. (E,F: Courtesy of Martin M. Malawer; G: From Malawer MM. Surgical management of aggressive and malignant tumors of the proximal fibula. Clin Orthop Relat Res 1984;186:172-181.)

▪ Fibular Diaphysis Resection Tumors of the fibular diaphysis, whether benign or malignant, are usually treated with intercalary resection of the affected diaphyseal segment. Tumor curettage is neither feasible nor effective due to the small diameter of the diaphysis. Furthermore, loss of an intercalary segment usually does not affect the

stability of knee and ankle joints or the overall function of the lower extremity. Benign tumors require resection of bone only, whereas highgrade sarcomas require en bloc removal of the surrounding cuff of muscles. Exposure Intercalary fibular resections are performed using the middle portion of the utilitarian incision with proximal or distal extension, according to anatomic extent of the affected segment. To expose the fibular diaphysis, the fascia is opened in line with the utilitarian incision. The plane between the peronei and the soleus is defined by the septum separating the two compartments. The soleus is detached from its fibular origin and, along with the lateral gastrocnemius muscle, is retracted medially and proximally to reveal the posterior crest of the fibula (TECH FIG 5). The flexor hallucis longus can be spared or resected, depending on the grade and local extent of the underlying tumor. The peronei are mobilized anteriorly, and retractors are positioned underneath the fibula. Tumor Removal Resection is performed at the level that had been determined before surgery. Care must be taken not to damage the peroneal vessels, which are posterior and parallel to the fibula (TECH FIG 5B,C). P.329 Reconstruction and Wound Closure Intercalary resections usually do not require osseous reconstruction. Low intercalary resections that leave only a short segment may require reinforcement of the lateral malleolus to preserve lateral ankle stability (TECH FIG 6A,B). Distal resections of the fibula, which are rarely done, require reconstruction because of the loss of a component of the ankle joint. Reconstruction with a microvascularized fibula is recommended. Alternatively, the ipsilateral fibula can be used for reconstruction. A type I resection of the proximal fibula is performed, and the fibular head and neck are attached to the tibial plafond with a screw and to the fibular shaft with a plate (TECH FIG 6C).

TECH FIG 5 • A. Plain radiograph showing fibrous dysplasia of the fibular diaphysis. B. Exposure of a benign aggressive tumor. The soleus (So) is detached from its fibular origin and, along with the lateral gastrocnemius muscle (G), is retracted medially and proximally to reveal the posterior crest of the fibula (arrow). The flexor hallucis longus can be spared or resected, depending on the grade and local extent of the tumor. The peronei muscles (Pe) are mobilized anteriorly, retractors are positioned underneath the fibula, and the resection is performed at the level determined before surgery. C. Intraoperative photograph following resection of the fibula. Particular attention has been paid to protect the peroneal and musculocutaneous nerves and associated vasculature. D. Postoperative radiograph. E. Plain radiographs showing Ewing sarcoma of the fibular diaphysis. F. The tumor is exposed using the upper two-thirds of the utilitarian fibular incision. (continued) P.330

TECH FIG 5 • (continued) G. Because of the extraosseous tumor extension, the soleus is split to expose and mobilize the neurovascular bundle; the muscle remains attached to the fibula. (B: Courtesy of Martin M. Malawer.)

TECH FIG 6 • A,B. Plain radiographs showing reinforcement of the lateral malleolus by means of a screw after low intercalary resection of the fibula. C. A distal fibular defect can be reconstructed with a microvascularized fibula from the contralateral leg or transposition of the ipsilateral proximal fibula.

PEARLS AND PITFALLS Proximal Fibula Resection Intraoperative

▪ Semisupine position with flexed knee using the utilitarian fibular incision ▪ Mobilization and protection of the peroneal nerve ▪ Exploration of the popliteal vessels, when required ▪ Selection of surgery (curettage/type I or II resection) according to tumor type and anatomic extent ▪ Reconstruction of the LCL attachment site after resection of the proximal fibula (FIG 4)

FIG 4 • Reconstruction of the LCL attachment site after resection of the proximal fibula. The biceps femoris, lateral head of the gastrocnemius muscle, and the soleus muscles are all used for soft tissue reconstruction of the surgical defect and for closure of the wound. Postoperative

▪ Specific rehabilitation according to the tumor type, including ankle-foot orthosis for patients who underwent type II resection

Fibular diaphysis resection

▪ A utilitarian incision of adequate length for wide exposure of the resected fibular segment ▪ En bloc resection of the surrounding cuff of muscles in high-grade sarcomas ▪ Mandatory reinforcement of the lateral malleolus in low intercalary resections

P.331

POSTOPERATIVE CARE AND REHABILITATION Proximal Fibula Resection Continuous suction is required for 3 to 5 days, and perioperative intravenous antibiotics are continued until the drainage tubes are removed. Early ambulation is encouraged with partial weight bearing for 3 weeks as well as passive and active range of motion of the knee joint. Unrestricted weight bearing is allowed upon wound healing. Postoperatively, the extremity is immobilized in a cast for 3 weeks in 20 degrees of knee flexion to allow soft tissue healing. After cast removal, full weight bearing is allowed as well as full active range of motion around the knee. An ankle-foot orthosis is required for patients who underwent type II resection and had foot drop because of peroneal nerve dysfunction. Patients who have high-grade sarcoma are treated with postoperative chemotherapy. Patients with Ewing sarcoma are further treated with radiation therapy consisting of external beam radiation of 6000 to 7000 Gy.

Fibular Diaphysis Resection

Continuous suction is required for 3 to 5 days, and perioperative intravenous antibiotics are continued until the drainage tubes are removed. This is followed by early ambulation with partial weight bearing for 3 weeks, together with passive and active range of motion of the knee joint. Unrestricted weight bearing is allowed after wound healing.

OUTCOMES Resections of the fibula, even those that require en bloc resection of the muscle cuff, are usually associated with minimal impact on lower extremity function. The weight-bearing capacity of the leg is not impaired and its major muscle groups usually remain intact. The only exception is the occurrence of foot drop and the need to use an ankle-foot orthosis after intentional resection of the peroneal nerve in a type II proximal fibular resection. Knee stability is similarly preserved when care is taken to adequately reconstruct the LCL attachment site and allow its healing and gradual loading.

COMPLICATIONS Peroneal nerve injury in curettage or type I resection of the proximal fibula Lateral knee instability due to inadequate LCL reconstruction or inadequate postoperative rehabilitation Lateral ankle instability because of inadequate fixation of the lateral malleolus in low intercalary resections of the fibular diaphysis Chronic swelling of the leg after extensive type II resection, requiring lymphatic drainage Deep infections

P.332

REFERENCES 1. Dorfman HD, Czerniak B. General considerations. In: Dorfman HD, Czerniak B, eds. Bone Tumors. St. Louis: CV Mosby, 1998:1-33. 2. Erler K, Demiralp B, Ozdemir T, et al. Treatment of proximal fibular tumors with en bloc resection. Knee 2004;11:489-496. 3. Faezypour H, Davis AM, Griffin AM, et al. Giant cell tumor of the proximal fibula: surgical management. J Surg Oncol 1996;61:34-37. 4. Farooque M, Biyani A, Adhikari A. Giant cell tumours of the proximal fibula. J Bone Joint Surg Br 1990;72B:723-724. 5. Malawer MM. Surgical management of aggressive and malignant tumors of the proximal fibula. Clin Orthop Relat Res 1984;186: 172-181.

6. Marcove RC, Jansen MJ. Radical resection for osteogenic sarcoma of fibula with preservation of the limb. Clin Orthop Relat Res 1977;125:173-176. 7. Ozaki T, Hillman A, Lindner N, et al. Surgical treatment of bone sarcomas of the fibula. Analysis of 19 cases. Arch Orthop Trauma Surg 1997;116:475-479.

Chapter 28 The Use of Free Vascularized Fibular Grafts for Reconstruction of Segmental Bone Defects Arik Zaretski Ravit Yanko-Arzi Yehuda Kollender Eyal Gur Jacob Bickels

BACKGROUND Wide resection of long bone tumors can create a large intercalary bone defect requiring reconstruction. Such defects were traditionally reconstructed with prosthetic implants, allografts, and allograft prosthetic composites, all of which were associated with considerably high rates of complications and failures.5 Distraction osteogenesis provides biologic reconstruction of only small- to medium-sized intercalary defects. Moreover, it is a prolonged procedure, which requires up to 2 months for an elongation of 1 cm, and complications are frequent, patient compliance is critical, and large soft tissue defects cannot be addressed simultaneously.8,12 Reported experience regarding safety and efficacy in the oncologic setup is also limited. Since the introduction of vascularized autogenous graft for long bone reconstruction after tumor resection in the early 1970s, the use of a free fibular flap has become a viable option for reconstruction of large intercalary bone defects following tumor resection or for the purpose of resection arthrodesis.3,4,6,9,10,11,13,15 Its inherent advantage is based on its ability to exploit the biology of normal fracture healing rather than the creeping substitution that is fundamental to the incorporation of a nonvascularized graft. The fibula is an optimal vascularized graft source because of its anatomic accessibility and because removing an intercalary segment while preserving the proximal fibula, distal tibial-fibular syndesmosis, and the lateral malleolus would have minimal impact on knee and ankle stability and would not compromise weight-bearing capacity and overall function of the lower extremity. It allows reconstruction of large bone defects because of its independent blood supply, which permits graft incorporation into the host bone even when presence or viability of the surrounding soft tissue are considerably compromised because of previous surgery or radiation therapy. Furthermore, a vascularized fibular graft has the capability to hypertrophy over time as a response to continuous pressure load. As a result, vascularized fibula have shown excellent long-term durability.2,9,16 The fibular head can also be used for joint reconstruction after intercalary resection of bone tumors.7 In summary, a free fibular graft provides a durable true biologic reconstruction with accommodative and regenerative capabilities associated with minimal short- and long-term complications.16 It requires a combined effort of highly trained and committed teams as well as the patient's compliance throughout a very long, complex, and demanding rehabilitation period.

APPLIED ANATOMY OF THE FIBULAR FLAP The fibula is long and narrow and therefore provides a strong cortical strut for reconstruction of long bone defects. It has a square cross-section in its superior part and is triangular in its inferior end. In the adult

patient, it can reach a width of 1.5 to 2 cm and a length of 35 cm, 25 to 30 cm of which can be harvested for the purpose of free grafting. Its shape and length can match bone segments of the upper extremity (humerus, radius, and ulna) or fit the medullary canal of bones of the lower extremity (femur, tibia); therefore, it can be used for reconstruction of bone defects at these sites. The fibula is circumferentially surrounded by muscle groups on its lateral, anteromedial, and posterior aspects and is also the origin of the four intermuscular septi of the leg. The blood supply and drainage of the fibular shaft are related to the peroneal vessels. The peroneal artery together with the two peroneal venae comitantes follow a course parallel to the fibula and lie between the flexor hallucis longus and tibialis posterior muscles (FIG 1). The fibula is dually vascularized through its endosteal and periosteal vessels. The endosteal blood supply is based on the nutrient artery, which stems 6 to 14 cm from the peroneal artery bifurcation, enters the middle third of the diaphysis via the nutrient foramen, and then divides into an ascending and a descending branch. The periosteal blood supply is derived from 8 to 9 periosteal branches, mostly in the middle third of the diaphysis. The peroneal artery is also the source of 4 to 6 fascial vessels that pass through the posterior intercrural septum to the skin territory, lateral to the fibula. It provides numerous muscular branches as well; specifically, it supplies multiple small branches to the muscles of the anterior compartment and a few larger branches to the soleus muscle at the deep posterior compartment of the leg. The unique morphologic characteristics and blood supply of the fibula allow considerable versatility in the use of the fibular flap for reconstruction of skeletal, soft tissue, and growth plate defects, as required. The fibular flap can be transferred in various configurations and compositions to suit the needs of individual cases: In its straight configuration, it can be used for reconstruction of a relatively narrow bone segment (FIG 2). A longitudinal osteotomy that increases the surface area of the flap can serve as an onlay graft to augment the healing process for partial cortical defects. Based on perforating fasciocutaneous branches at the middle and distal thirds of the pedicle, a skin paddle of up to 20 × 10 cm can be transferred simultaneously to facilitate coverage of concomitant large soft tissue defects and to allow the patency P.334 of the pedicle anastomosis to be monitored. Part of the soleus or the flexor hallucis longus muscles can also be included with the flap to reconstruct soft tissue defects and cover exposed bone.

FIG 1 • The blood supply and drainage of the fibula are related to the peroneal artery and two peroneal veins, which follow a course parallel to the fibula. The fibula has a dual blood supply: endosteal and periosteal. The former is based on a nutrient artery that stems 6 to 14 cm from the peroneal bifurcation and the latter is based on multiple periosteal branches along the fibular diaphysis. Transverse osteotomies can be made through the middiaphysis to produce two or more cortical struts on a single pedicle (double/triple barrel) for reconstruction of a wide bone segment. In these cases when the endosteal vessels are transected, the bone survives on its periosteal system.

FIG 2 • Diaphyseal fibular graft, used for reconstruction of intercalary bone defects. If a long segment is required and the osteotomy is closed to the lateral malleolus, screw fixation to the tibia is advised to prevent valgus deformity and ankle instability. The proximal epiphysis may be included in the flap for joint reconstruction and preservation of longitudinal growth potential (in pediatric patients) after intra-articular resection of bone tumors (FIG 3). This flap is based on the anterior tibial vascular flap or the descending geniculate artery and is most commonly used for reconstructions following resections of the proximal humerus and distal radius.

INDICATIONS Segmental bone defects larger than 5 cm following resection due to the following: Tumor Radiation-induced bone necrosis

Osteomyelitis In cases of high-grade sarcomas of bone, the authors generally use spacers for immediate reconstruction following tumor resection rather than performing the definitive reconstruction with vascularized fibula. The latter is carried out 2 years after tumor resection if there had been no tumor recurrence or lung metastases.

CONTRAINDICATIONS Systemic/general conditions Cardiovascular, surgical, or hematologic diseases that may affect peripheral blood flow

FIG 3 • Proximal fibular graft that includes the proximal fibular epiphysis and based on the anterior tibial vascular pedicle may be used for joint reconstruction and preservation of longitudinal growth in children following intra-articular resection of bone tumors.

P.335 Incompliance with or if patient's physical or psychological states do not allow to withstand a prolonged nonweight bearing and/or rehabilitation Poor general health status Donor site considerations Fibular deformity following previous injury to the lower extremity Vascular injury or compromise following previous trauma to the leg Vascular anomalies of the leg or plantar arches (eg, singlevessel or peroneal vessel-dominant foot) Recipient site considerations Infection around the recipient site Suspected tumor recurrence

IMAGING AND OTHER STAGING STUDIES Detailed preoperative evaluation of both the recipient and donor sites is mandatory. Imaging of the recipient site should provide information regarding the dimensions of bone (length and diameter) and soft tissue defects remaining after tumor resection, thus allowing the selection of the appropriate type and size of fibular flap to be used. Imaging of the donor site should include the entire leg and is aimed at excluding fibular deformity and at determining maximal flap length. The surgeon should verify adequate pulses in both posterior tibial and dorsalis pedis arteries. Evaluation of the deep and superficial plantar vascular arches is done using an equivalent to the palmar Allen test and is confirmed by Doppler ultrasound examination. If those studies are nonconclusive, an angiography or computed tomography angiography (CTA) is performed.

Recipient Site Plain radiography (FIG 4AB) CTA when the vascular anatomy is unclear (FIG 4C) Magnetic resonance imaging (MRI)

FIG 4 • A. Plain radiograph of the tibia showing a large diaphyseal low-grade osteosarcoma. B. Plain radiograph of the arm showing considerable bone loss and pathologic fracture associated with acute osteomyelitis of the humeral diaphysis. C. Coronal CT reconstruction of the distal forearm showing an osteosarcoma of the distal radius.

Donor Site Plain radiography CTA Doppler ultrasound (done intraoperatively to detect the skin island perforants)

SURGICAL MANAGEMENT To minimize the duration of surgery and if the patient's position on the operating table permits, the fibular flap is harvested simultaneously with the preparation of the recipient site, a procedure that may include resection of the primary bone tumor or removal of a spacer that had been used in a previous surgery for reconstructive purposes.

Intercalary Resection As a rule, a vascularized fibula in its straight and simple configuration is sufficient for reconstruction of bone defects of the upper extremity because of the relatively narrow crosssectional diameter of the latter. Reconstruction of such defects of the lower extremity requires graft material of a larger diameter because of the additional mechanical support needed. A double-barrel fibular flap can be used for reconstruction of femoral and tibial defects of up to 13 cm. Longer defects may require the support of an allograft, which provides the initial stability required for bone healing, graft incorporation, and subsequent fibular hypertrophy.

Furthermore, in cases of failed vascular anastomosis, the combined fibular-allograft construct is still comparable to multiple cortical allogenic struts with a relatively good chance of success, especially if reliable fixation is achieved. The technique of combined reconstruction with an allograft and the vascularized fibula, as described by Capanna and his colleagues,1,2 provides such stability and is the preferred method of reconstruction used by the authors for long intercalary defects of the lower extremities. P.336

TECHNIQUES ▪ Position and Incision For treating a bone defect of the lower extremity, the patient is placed supine on the operating table with the thighs spread apart. The hip and knee of the donor extremity are flexed (TECH FIG 1). The first team, which is responsible for tumor resection, (blue team) is positioned along the medial or lateral side of the recipient extremity.

TECH FIG 1 • The patient is placed supine on the operating table with the thighs spread apart with the

hip and knee of the donor extremity in flexion. The team responsible for tumor resection (in blue) is positioned along the medial or lateral of the recipient extremity, as requires. The team responsible for removal of the fibular graft from the donor extremity (in red) is positioned along its lateral aspect of the donor extremity. If tumor resection is done from the medial side of the extremity, a surgeon can be positioned at that aspect. A second (red) team, responsible for the harvest of the fibular flap from the donor extremity, is positioned along its lateral.

▪ Resection of Bone Tumor The bone tumor is removed according to the standard techniques, and the length and diameter of the intercalary bone defect are measured (TECH FIGS 2,3 and 4).

TECH FIG 2 • Diaphyseal tumor is resected with wide margins, leaving a long intercalary bone defect.

TECH FIG 3 • A. Intraoperative photograph of the large diaphyseal low-grade osteosarcoma of the tibia shown in FIG 4A. B. Large intercalary defect remaining after wide tumor resection. P.337

TECH FIG 4 • Following tissue sampling and cultures, administration of intravenous antibiotics, and resolution of acute manifestation of infection, the patient in FIG 4B with acute osteomyelitis of the humeral diaphysis underwent resection of the infected bone tissue, leaving a long intercalary bone defect.

▪ Harvest of a Fibular Flap and Allograft Using an anterolateral incision at the contralateral leg, an intercalary fibular segment that is 6 cm longer than the bone defect is harvested together with its nutrient vessels and its periosteal cuff (TECH FIG 5). If a large skin defect is anticipated at the tumor resection site, the fibular flap is harvested with an overlying skin island supplied by the same peroneal artery, which allows tensionfree skin closure as well as early detection of flap-compromised viability: Arterial or venous compromise would instantly be expressed by ischemic or congestion changes of the skin island (TECH FIG 6).

TECH FIG 5 • A. An anterolateral leg incision is used for harvesting of the fibular flap. B. An intercalary fibular segment, 6 cm longer from the bone defect, with its periosteal cuff is harvested.

TECH FIG 6 • A-F. If a large skin defect is anticipated at the tumor resection site, the fibular graft is removed with an overlying skin island, which is used for coverage of that defect and for monitoring of flap viability. (continued) P.338

TECH FIG 6 • (continued) The skin island is removed without the underlying fascia; it is preserved to maintain the biologic coverage of the peroneal tendons and allow better skin graft take (TECH FIG 7). If a long bony segment is required and the osteotomy is close to the lateral malleolus, screw fixation to the tibia is advised to prevent valgus deformity and ankle instability (see FIG 2). A skin graft, usually taken from the thigh of the donor extremity, is used to cover the skin defect in that leg.

TECH FIG 7 • Skin is harvested and the underlying fascia is left intact over the peroneal tendons. The allograft is cut to the same length as the bone defect, and a groove is opened longitudinally by removing as much cortical and cancellous bone as needed to allow insertion of the fibular flap into it. P.339

▪ Reconstruction of the Recipient Site The allograft is inserted to fill the bone defect and fixed to its proximal and distal edges with a side plate and screws (TECH FIG 8). An intramedullary nail is also used if the diameter of the allograft medullary canal is wide enough to contain both the nail and the fibular graft. Using a high-speed burr, a defect is created in the allograft cortex at the appropriate level to allow the passage of the fibular vascular pedicle toward the vascular bundle of the recipient extremity while avoiding traction on the vascular anastomosis. The fibular graft is inserted 2 to 3 cm into the medullary canal at both ends and fixed with screws (TECH FIG 9). Care is taken to prevent damage to the nutrient vessels of the fibula by those screws. The fibula can be placed in an intramedullary location, inside the allograft or parallel to it. In both options, the fibular

osteotomy sites should lie in close approximation to the native long bone resected edges.

TECH FIG 8 • A. The allograft is cut to the same length as the bone defect, and a groove is opened longitudinally by removing as much cortical and cancellous bone as needed to allow insertion of the fibular graft into it. It is then inserted to fill the bone defect and fixed to its proximal and distal edges with a side plate and screws. B. A defect is created in the allograft cortex to allow the passage of the fibular vascular pedicle. After vascular anastomoses are completed, an autologous bone graft, taken from the fibular flap remnants or the ipsilateral iliac crest, is used to reinforce the interface between the fibula and the recipient bone.

TECH FIG 9 • A. Intercalary defect of the distal femur is filled with canoe-shaped allograft. B. The free vascularized fibula is inserted into the allograft's medullary canal. A small skin island is included to allow monitoring of flap perfusion. C. Plain radiograph in a different patient showing the fibular graft inserted into the allograft's medullary canal and fixed with screws. P.340

▪ Intra-articular Resections The proximal fibular epiphysis with variable lengths of the diaphysis and with the anterior tibial vessels as the vascular pedicle or alternatively the inferior geniculate artery is used for reconstruction of defects that include one side of the articular surface.

TECH FIG 10 • Following removal of a proximal fibular graft, the stump of the lateral collateral ligament is secured to the lateral tibial metaphysis to restore lateral knee joint stability. Following harvest of the fibular flap, the lateral collateral ligament is secured to the medial tibial metaphysis with a metal staple to preserve lateral knee joint stability (TECH FIG 10). The proximal aspect of the fibular flap is fixed to the radial or humeral diaphysis with a side plate and screws, and the biceps tendon stump is used for attachment to the opposing articular surface soft tissue envelope (TECH FIGS 11 and 12).

TECH FIG 11 • Reconstruction of proximal fibular graft to the remaining radial diaphysis.

TECH FIG 12 • Anteroposterior (A) and lateral (B) plain radiographs of the patient in FIG 4C with osteosarcoma of the distal radius showing reconstruction of the intercalary bone defect with a proximal fibular graft.

P.341

PEARLS AND PITFALLS Fibular flap monitoring

▪ When a skin island is included in the fibular flap, an external pencil Doppler is used to monitor blood circulation. If the flap is buried, an implantable Cook-Swartz Doppler is used for monitoring. The use of implantable Doppler in surgery also allows detection of impairment of venous outflow during wound closure14 (FIG 5).

FIG 5 • A. An implantable Cook-Swartz Doppler is used to monitor fibular flap perfusion. B. Following wound closure, flap perfusion is monitored by the implantable Doppler and viability of the overlying skin island.

POSTOPERATIVE CARE AND REHABILITATION All patients must be treated and monitored postoperatively according to a strict and constant protocol. They are admitted to the department of plastic surgery for the first 5 days after surgery, where they are monitored for vital signs and flap viability and administered a mildly elevated volume of lactated Ringer solution (1.2 times the maintenance) to maintain blood flow through the anastomosis and prevent thrombus formation. This fluid protocol is maintained for a total of 5 days. Enoxaparin is given for prevention of deep vein thromboses. Blood samples are drawn twice daily for blood count and electrolytes. Hemoglobin levels are kept between 9 and 10 g/mL to minimize blood viscosity and further decrease the likelihood of anastomotic thrombus. Recipient extremities are immobilized for 3 months (an upper extremity by a brace and a lower extremity by a plaster cast) after which gradual passive ranges of motion are practiced. Signs of bony union are evaluated radiologically by serial plain radiographs. Bone unions are usually seen after 4 to 5 months in the upper extremity and after 5 to 7 months in the lower extremity. Partial weight bearing is allowed on detection of radiologic evidence of bone union. Gradual physical loads on the limb are recommended until full weight bearing is achieved.

OUTCOMES Solid bony unions associated with fibular hypertrophy, full weight bearing, and mechanical load capacities are achieved in the vast majority of patients. Fibular hypertrophy occurs over years and is the result of pressure transport, microfractures, and callus formation. Mild to moderate decreases in range of motion are common and of a similar extent to those seen after other types of reconstructive surgeries. The latter is the result of the extent of resection of bone and soft tissues rather than the mode of reconstruction. Deep infections are rare, as is hardware failure requiring revision surgery.

COMPLICATIONS Recipient site Anastomotic thrombosis and loss of flap viability Partial skin island necrosis Nonunion Infection Hardware failure and breakage Donor site Valgus ankle deformity Ankle joint instability Transient or permanent peroneal palsy Transient or permanent peroneal distribution area sensory deficit Skin graft failure and tendon exposure

Transient or permanent great toe flexion impairment

REFERENCES 1. Capanna R, Bufalini C, Campanacci M. A new technique for reconstructions of large metadiaphyseal bone defects. Orthop Traumatol 1993;3:159-177. 2. Capanna R, Campanacci DA, Belot N, et al. A new reconstructive technique for intercalary defects of long bones: the association of massive allografts with vascularized fibular autograft. Long-term results and comparison with alternative techniques. Orthop Clin North Am 2007;38:51-60. 3. Chang DW, Weber KL. Use of a vascularized fibula bone flap and intercalary allograft for diaphyseal reconstruction after resection of primary extremity bone sarcomas. Plast Reconstr Surg 2005;116: 19181925. 4. Gebert C, Hillmann A, Schwappach A, et al. Free vascularized fibular grafting for reconstruction after tumor resection in the upper extremity. J Surg Oncol 2006;94:114-127. 5. Getty PJ, Peabody TD. Complications and functional outcomes of reconstruction with an osteoarticular allograft after intra-articular resection of the proximal part of the humerus. J Bone Joint Surg 1999;81(8):1138-1146. 6. Innocenti M, Delcroix L, Manfrini M, et al. Vascularized proximal fibular epiphyseal transfer for distal radial reconstruction. J Bone Joint Surg Am 2004;86:1504-1511. 7. Innocenti M, Delcroix L, Manfrini M, et al. Vascularized proximal fibular epiphyseal transfer for distal radial reconstruction. J Bone Joint Surg Am 2005;87:237-246. P.342 8. Kocaoglu M, Eralp L, Rashid H, et al. Reconstruction of segmental bone defects due to chronic osteomyelitis with use of an external fixator and an intramedullary nail. J Bone Joint Surg Am 2006;88: 21372145. 9. Malizos KN, Zalavras CG, Soucacos PN, et al. Free vascularized fibular grafts for reconstruction of skeletal defects. J Am Acad Orthop Surg 2004;12:360-369. 10. McKee DM. Microvascular bone transplantation. Clin Plast Surg 1978;5:283-292. 11. O'Brien BM, Morrison WA, Ishida H, et al. Free flap transfers with microvascular anastomoses. Br J Plast Surg 1974;27:220-230. 12. Paley D. Problems, obstacles, and complications of limb lengthening by the Ilizarov technique. Clin Orthop Relat Res 1990;250:81-104.

13. Rose PS, Shin AY, Bishop AT, et al. Vascularized free fibula transfer for oncologic reconstruction of the humerus. Clin Orthop Relat Res 2005;438:80-84. 14. Schmulder A, Gur E, Zaretski A. Eight-year experience of the Cook-Swartz Doppler in free-flap operations in microsurgical and reexploration results with regard to a wide spectrum of surgeries. Microsurgery 2011;31(1):1-6. 15. Taylor GI, Miller GD, Ham FJ. The free vascularized bone graft. A clinical extension of microvascular techniques. Plast Reconstr Surg 1975;55:533-544. 16. Zaretski A, Amir A, Meller I, et al. Free fibula long bone reconstruction in orthopedic oncology: a surgical algorithm for reconstructive options. Plast Reconstr Surg 2004;113:1989-2000.

Chapter 29 Quadriceps Resections Jacob Bickels Yair Gortzak Amir Sternheim Martin M. Malawer

BACKGROUND The quadriceps muscle group is the most common site for extremity soft tissue sarcomas. The most common sarcomas at this site are liposarcomas, undifferentiated pleomorphic sarcomas, and leiomyosarcomas. Although tumors of the anterior compartment of the thigh can be extremely large at presentation, it is possible to perform limb-sparing resections in most patients. By using induction chemotherapy and either preoperative or postoperative adjuvant radiation therapy to eradicate possible residual microscopic disease, resections of the anterior compartment of the thigh are often feasible and safe. In addition, when resection necessitates en bloc removal of a considerable amount of muscle tissue, reconstruction of the extensor mechanism with the sartorius muscle, the hamstring muscles, or both produces good functional results. The most common indications for amputation (ie, hip disarticulation or hemipelvectomy) are very large tumors with extracompartmental extension into the adductor and hamstring musculature, tumors with intrapelvic extension through the femoral triangle and inguinal ligament, large fungating tumors, and massive tumor contamination, with or without infection.

ANATOMY The thigh consists of three distinct anatomic compartments, separated by thick fascial layers: the anterior compartment (quadriceps and sartorius muscle), the medial compartment (thigh adductor muscles), and the posterior compartment (the hamstring muscles). The quadriceps muscle group consists of the vastus medialis, vastus lateralis, rectus femoris, and vastus intermedius muscles. The vastus medialis and lateralis arise from the proximal femur and intermuscular septum. The vastus intermedius arises from the surface of the femur and the linea aspera and covers the entire femoral shaft. The rectus femoris arises from the supra-acetabular tubercle at the superior part of the acetabulum. All four heads merge distally into the quadriceps tendon, which inserts onto the patella. By covering the anterior aspect of the femur, the vastus intermedius protects the underlying femur from direct tumor extension by tumors of the other components of quadriceps muscle. The fact that soft tissue sarcomas often remain localized to one muscle belly permits partial muscle group resection for many quadriceps sarcomas (FIG 1). The medial and lateral intermuscular septum of the thigh separates the anterior thigh muscles from the medial and posterior compartments, respectively. However, the medial intermuscular septum “runs out” proximally, and quadriceps tumors may therefore extend into the posterior and medial compartments and complicate and sometimes obviate a limb-sparing resection. Likewise, tumors arising from the medial and posterior

compartments of the thigh may extend into the quadriceps group. The femoral triangle is the key to resection of the quadriceps muscle group. It is formed by the adductor longus medially, the sartorius muscle laterally, and the inguinal ligament proximally. The pectineus muscle forms the floor of the triangle. A thick fascia covers the roof. The superficial femoral artery and vein pass from below the inguinal ligament through the femoral triangle and into the sartorial canal at the apex. The femoral nerve enters the canal laterally and quickly branches to innervate the quadriceps muscle components. The superficial femoral artery and vein pass along the medial wall of the sartorial canal throughout the length of the thigh and are separated from the anterior group (vastus medialis) by a thick fascia, which often permits a safe resection. This fascia forms a good border for quadriceps resections.

FIG 1 • Quadriceps resection types. Type A, resection of the vastus lateralis. Type B, resection of the vastus medialis. Type C, resection of the rectus femoris and vastus intermedius. Type D, subtotal resection of the quadriceps muscle. Type A and B resections often include the vastus intermedius as well. P.344

INDICATIONS Almost all low-grade soft tissue sarcomas of the anterior thigh may be safely resected by a partial muscle group resection. The large majority of high-grade soft tissue sarcomas can be resected by partial or total

compartmental removal. The contraindications to limb-sparing resection are as follows: Groin involvement: Tumors arising or involving the groin and femoral triangle often cannot be reliably resected and may require amputation. Extracompartmental extension: In general, resection of a single muscle group permits a viable extremity. If two muscle groups have to be completely removed, the extremity may not be functionally salvageable. Large tumors of the anterior thigh may involve the adductor group as well as the posterior muscle group by passing through the linea aspera or the intermuscular septum. In this situation, amputation might be necessary. Intrapelvic extension: On rare occasions, large tumors of the proximal thigh and groin extend below the inguinal ligament into the retroperitoneal space, necessitating amputation. Recurrent tumors of the quadriceps, infection, extensive tumor hemorrhage, or extensive tumor contamination from previous surgical procedures may require amputation. Neurovascular involvement of the tumor does not necessarily obviate limb salvage resections. Most tumors of the quadriceps muscle will displace but not invade the superficial femoral or common femoral arteries. If the surgical margins are positive for tumor cells or extremely close, resection of the involved artery and replacement with a vascular graft often allows limb salvage. En bloc resection of the femoral nerve is also not a contraindication for limb-sparing resection; reconstruction techniques often provide patellar stabilization and allow limited knee extension, even when the entire quadriceps muscle is resected or paralyzed secondary to femoral nerve resection (Tables 1 and 2).

Table 1 Histopathologic Diagnoses of 15 Patients Treated with Soft Tissue Tumor Resection from the Anterior Compartment of the Thigh and Extensor Mechanism Reconstruction Number of Patients

Tumor Type Malignant soft tissue tumors

Benign aggressive soft tissue tumors Total

Malignant fibrous histiocytoma

4

High-grade liposarcoma

3

Recurrent low-grade liposarcoma

1

Leiomyosarcoma

3

Malignant peripheral nerve sheath tumor

2

Recurrent aggressive fibromatosis

2

15

Table 2 Grading System for Quadriceps Muscle Strength Grade

Value

Movement

5

Normal

Able to extend knee against gravity with maximal resistance

4

Good

3

Fair

Able to extend knee against gravity

2

Poor

Able to extend knee when gravity eliminated

1

Trace

Evidence of slight contractility but no joint movement

0

Zero

No contraction palpated

Able to extend knee against gravity with some (moderate) resistance

Modified from Sapega AA. Muscle performance evaluation in orthopaedic practice. J Bone Joint Surg Am 1990;72(10):1562-1574.

Unique Anatomic Considerations An important criterion for the success of a muscle flap transfer (FIG 2A-D) is maintenance of a pattern of circulation that is consistent in location and resistant to the effect of radiation therapy and superficial trauma (FIG 2E). The surgical manipulation of the muscle flap must not interrupt its circulation; therefore, a precise knowledge of the location and pattern of the vascular pedicles is required. The sartorius muscle is supplied by the superficial femoral artery and has a segmental vascular pattern (type IV vascular pattern according to Mathes and Nahai6). Each pedicle provides circulation to a portion of the muscle, and division of more than three pedicles during the elevation of the flap may result in distal muscle necrosis. The hamstring muscles are supplied by branches of the profunda femoris artery and have proximal dominant vascular pedicles and distal minor pedicles (type II vascular pattern). Complete elevation of the muscles is possible when the dominant proximal vascular pedicles are preserved.

IMAGING AND OTHER STAGING STUDIES Computed Tomography and Magnetic Resonance Imaging Magnetic resonance imaging (MRI) and computed axial tomography (CAT) cross-sectional imaging are essential for determining the location and extent of the lesion and its relations to the femur and the neuromuscular bundle. Large tumors of the quadriceps muscle often displace the superficial and deep femoral vessels (FIG 3). It is important to determine the anatomic relations of these vessels to the tumor before resection. Large tumors of the proximal thigh may require ligation of the profundus femoris artery and vein; therefore, knowing before surgery whether the superficial artery is patent is essential. This is particularly true in the older patient in whom the superficial femoral artery may be occluded secondary to peripheral vascular disease. Displacement of the superficial femoral artery usually does not indicate direct tumor extension;

however, if the surgical margins are positive, the artery should be resected and replaced with a saphenous or artificial graft. P.345

FIG 2 • A. Muscle transfers for type A resection (vastus lateralis with or without vastus intermedius). The long head of the biceps femoris is transferred anteriorly and sutured to the patella, the quadriceps tendon, and the rectus femoris muscle. B. Muscle transfers for type B resection (vastus medialis with or without vastus intermedius). The sartorius muscle is transferred anteriorly but not detached from its distal insertion and is sutured to the patellar tendon, patella, quadriceps tendon, and rectus femoris muscle. C. Muscle transfers for type C resection (rectus femoris and vastus intermedius). The sartorius muscle is mobilized anteriorly and sutured to the patella and the remains of the quadriceps tendon. D. Muscle transfers for type D resection (subtotal resection). The biceps femoris laterally and the sartorius and semitendinosus medially are transferred anteriorly, tenodesed to each other, and sutured to the patella. E. Vascular anatomy of muscles. There are five patterns of vascular supply to muscles based on the distribution of major and minor vascular pedicles. The sartorius muscle has a type II vascular pattern, and the hamstring muscles have a type IV vascular pattern (represented by the gracilis muscle in the schematic).

P.346

FIG 3 • Axial (A) and coronal (B) MR views of a large soft tissue sarcoma of the anterior compartment of thigh. The neurovascular bundle is compressed medially. The tumor, however, does not reach the anterior aspect of the femur and a plane of dissection exits. Tumors may remain within one muscle belly or involve several components of the quadriceps muscle. It is important to identify the relationship between the tumor and the underlying femur. Tumors that involve the vastus medialis very often involve the adjacent periosteum as well.

Bone Scanning A three-phase bone scan is useful to determine the proximity of the tumor to the periosteum. Absence of periosteal uptake indicates a reactive border or a pseudocapsule. This does not make quadriceps tumors unresectable but indicates that the underlying periosteum must be removed during the surgical procedure. Rarely does tumor extend directly into the bone.

Biopsy The biopsy site should be in line with the planned incision for resection and must be located over the most prominent portion of the tumor. The biopsy tract should preferably violate a single muscle and avoid the neurovascular bundle. Computed tomography- and ultrasound-guided core needle biopsy has been shown to provide reliable pathologic diagnoses and is our preferred method. Multiple samples can be collected from the same puncture site.

SURGICAL MANAGEMENT Positioning The patient is placed in the supine position with a bolster underneath the ipsilateral buttock. If the tumor is close to or involves the femoral artery, the contralateral leg should also be draped for

saphenous vein graft harvesting, in case the femoral artery needs to be resected (FIG 4).

FIG 4 • Position and incision marked for type A resection (vastus lateralis and vastus intermedius) and reconstruction with biceps femoris transfer for a large malignant soft tissue sarcoma in the lateral aspect of the anterior compartment of the thigh. Resection included the vastus lateralis and part of the vastus intermedius and rectus femoris. After completion of the resection, the lateral aspect of the femur was exposed. The long head of the biceps femoris was transferred anteriorly and sutured to the patella and the remains of the quadriceps tendon and rectus femoris. P.347

TECHNIQUES ▪ Limited Resections of the Quadriceps Muscle Most tumors of the anterior compartment of the thigh are confined to one part of the quadriceps muscle and can be safely resected with negative margins without the need to sacrifice a considerable amount of muscle tissue. A longitudinal skin incision just above the tumor mass is made, encompassing the biopsy site. The tumor mass should be resected en bloc with 1 cm of surrounding healthy tissue. For tumors that involve the vastus medialis, vastus lateralis, or rectus femoris, the superficial margins are the skin and subcutaneous tissues and the deep margins may include part of the vastus intermedius. The superficial margins of tumors that involve the vastus intermedius may include part of one of the vasti or rectus femoris. If the deep surface of the tumor is close to the bone, the periosteum should be peeled off and resected and the superficial cortex removed with a high-speed burr (Midas).

▪ Partial or Complete Quadriceps Resection A long midline incision is made extending longitudinally from the anterior inferior iliac spine to the patella. It should be elliptical and should widely encompass the biopsy site (TECH FIG 1A).

Flaps composed of skin and subcutaneous tissue are made just superficial to the fascia lata. They extend to the adductor muscle group medially and to the greater trochanter and flexor muscles laterally. The saphenous vein is divided as it enters the fossa ovalis. The inguinal ligament and the femoral triangle are uncovered, exposing the common femoral artery and vein and the femoral nerve (TECH FIG 1B). Lateral traction is placed on the quadriceps muscle group so that muscular branches coming from the superficial femoral artery and vein into the quadriceps muscle are exposed. Working from cranial to caudal, these vessels are clamped, divided, and ligated, including the profunda femoris artery and vein. In the area of the canal of Hunter, while strong lateral traction is placed on the sartorius muscle, muscular insertions from the adductor magnus muscle coursing over the superficial femoral artery are identified. These muscular branches should be divided as they cross the superficial femoral artery (TECH FIG 1C,D). A plane beneath the tensor fascia lata muscle and above the gluteus medius and minimus is identified. By electrocautery, the tensor fascia lata muscle is released from its origin on the wing of the ilium. Then the origin of the sartorius muscle on the anterior superior iliac spine is identified and divided. The origin of the rectus femoris muscle on the anterior inferior iliac spine is likewise identified and divided through its tendinous portion (TECH FIG 1E).

TECH FIG 1 • A. The incision extends longitudinally from the anterior inferior iliac spine to the patella. It should be elliptical and should widely encompass the biopsy site. If physical examination or tomography shows that the tumor encroaches on the patella, this bone and its tendon should also be excised. If this clinical situation arises, the incision should be continued over the knee to the tibial tubercle. B. Crosssectional anatomy. (continued) P.348

TECH FIG 1 • (continued) C. Flaps composed of skin and subcutaneous tissue are made just superficial to the fascia lata. They extend to the abductor muscle group medially and to the greater trochanter and flexor muscles laterally. The saphenous vein is divided as it enters the fossa ovalis. The inguinal ligament and the femoral triangle are uncovered, exposing the common femoral artery and vein and the femoral nerve. D. Dissection of the superficial femoral vessels. Lateral traction is placed on the quadriceps muscle group so that muscular branches coming from the superficial femoral artery and vein into the quadriceps muscle are exposed. Working from cranial to caudal, these vessels are clamped, divided, and ligated, including the profunda femoris artery and vein. In the area of the canal of Hunter, when strong lateral traction is placed on the sartorius muscle, muscular insertions from the adductor magnus muscle coursing over the superficial femoral artery are identified. These muscle fibers should be divided as they cross the superficial femoral artery. E. Transection of muscle origins on the pelvis. A plane beneath the tensor fascia lata muscle and above the gluteus medius and minimus is identified. By electrocautery, the tensor fascia lata muscle is released from its origin on the wing of the ilium. Then the origin of the sartorius muscle on the anterior superior iliac spine is identified and divided. The origin of the rectus femoris muscle on the anterior inferior iliac spine is likewise identified and divided through its tendinous

portion. (continued) P.349

TECH FIG 1 • (continued) F. Resection includes the vastus lateralis and part of the vastus intermedius and rectus femoris. G. Transection of muscle origins on the femur. Origins of the vastus lateralis, vastus intermedius, and vastus medialis on the femur are transected from bone by using electrocautery. Strong upward traction on the muscle group facilitates this dissection. H. Transection of the muscle insertions of the quadriceps muscle. Using strong upward and medial traction on the specimen, the insertions of the vastus lateralis, vastus medialis, and rectus femoris into the patellar tendon are divided on the patella. The insertion of the vastus medialis into the medial collateral ligament is likewise divided, and the specimen is then free. The dissection site is copiously irrigated, and any bleeding points are secured with ligatures or electrocautery. (continued) P.350

TECH FIG 1 • (continued) I. To facilitate rehabilitation by helping to provide stability to the knee, the gracilis muscle medially and the short head of the biceps muscle laterally are transected at their insertions on the medial and lateral collateral ligaments. This transection should be as far distal as possible so that a tendinous portion of the muscle is retained. Then, using heavy, nonabsorbable sutures, these two muscles are transplanted onto the patellar tendon. The prepatellar and quadriceps bursae are closed within these sutures. The muscles are approximated in the midline to cover the distal third of the femur. J. After completion of the resection, the lateral aspect of the femur is exposed. K. Suction catheters are placed beneath the skin flaps, and the subcutaneous tissue is approximated. The skin is closed, and the incision is covered with povidone-iodine ointment and a loose, dry sterile dressing. The patient may begin ambulation when the suction catheters have been removed and edema of the leg has resolved. Because the lymphatics along the superficial femoral artery and within the buttock remain intact, prolonged swelling is not usually a problem; serous drainage from transected muscle bundles does not occur in large amounts. The patient is ambulated initially with crutches and a touchdown gait. The origins of the vastus lateralis, vastus intermedius, and vastus medialis on the femur are transected from the bone using electrocautery. Strong upward traction on the muscle group facilitates this dissection (TECH FIG 1F,G). Using strong upward and medial traction on the specimen, the insertions of the vastus lateralis, vastus medialis, and rectus femoris into the patellar tendon are divided on the patella (TECH FIG 1H). One cannot avoid transecting both the prepatellar and quadriceps (postpatellar) bursae. The insertion of the vastus medialis into the medial collateral ligament is likewise divided, and the specimen is then free. The dissection site is copiously irrigated, and any bleeding points are secured with ligatures or electrocautery. If the tumor is close to the underlying femoral bone (TECH FIG 1I), the periosteum can be removed and the underlying bone exposed using a high-speed burr (Midas). Several millimeters of the outer cortex can

be removed; however, the outer cortex itself should not be removed en bloc. Suction catheters are placed beneath the skin flaps, and the subcutaneous tissue is approximated with interrupted absorbable sutures. We recommend using 28-gauge chest tubes to drain the surgical space (TECH FIG 1K). Fluid-Filled Masses Occasionally, soft tissue sarcomas present as a large cystic mass, filled with necrotic and hemorrhagic fluid. These tumors are difficult to resect because they fill the affected compartment and neurovascular bundle is pressed and usually located at the base of the tumor and cannot be reached (TECH FIG 2A-C). In these cases, we drain the fluid from the tumor before the resection (TECH FIG 2D-F). This maneuver results in a considerable reduction in the volume of the tumor and provides better visualization and easier manipulation of the contents of the compartment (TECH FIG 2G). P.351

TECH FIG 2 • Axial (A) and coronal (B) MR views of an extensive cystic soft tissue sarcoma of the anterior compartment of thigh. The tumor is filled with necrotic and hemorrhagic fluid. C. The tumor caused

considerable tension and associated discomfort in the anterior compartment. D. The tumor is exposed. The ballooning is the result of the large volume of fluid in its inner cavity. E. Through a purse-string suture, a large caliber drain is inserted into the tumor cavity. The fluid is drained, the tumor shrinks, and the opening in the tumoral wall is tightly sutured to prevent leakage. F. The drained fluid. G. The anterior compartment following tumor removal. The femur is exposed; periosteal stripping was done. P.352

▪ Soft Tissue Reconstruction of Residual Large Defects If a significant amount of quadriceps muscle is resected or if the femoral nerve must be sacrificed, we routinely reconstruct the extensor mechanism to restore strength and balance patellar tracking. The long head of the biceps femoris muscle is used to reconstruct the lateral aspect of the quadriceps muscle (TECH FIG 3), and the sartorius muscle, the semitendinosus muscle, or both are used to reconstruct the medial aspect of the quadriceps muscle. Another technique that can be used to functionally reconstruct large defects (which is not within the scope of this textbook) is latissimus dorsi microvascular transplantation. We believe it should be used whenever muscle transfers cannot be performed.

TECH FIG 3 • The long head of the biceps femoris is transferred anteriorly and sutured to the patella and the remains of the quadriceps tendon and rectus femoris (RF).

▪ Biceps Femoris Transfer for Functional Reconstruction of Large Lateral Soft Tissue Defects After completion of the resection, the long head of the biceps is transected from its insertion on the head of the fibula. This transection should be as far distal as possible to retain a tendinous portion of the muscle. The muscle is transferred anteriorly to the midline so that it will have an almost direct line of pull. Only a few deep perforating branches need to be ligated during this procedure. Because of the type II vascular pattern of the hamstring muscles, ligation of distal branches does not jeopardize its vitality.

Then, using heavy, nonabsorbable sutures, the muscle is transplanted onto the patella and the remains of the quadriceps tendon and rectus femoris.

▪ Sartorius and Semitendinosus Muscle Transfer for Functional Reconstruction of Central and Medial Soft Tissue Defects The sartorius, the semitendinosus, or both can be used to functionally reconstruct large medial defects. Large central defects are reconstructed with the sartorius muscle. Semitendinosus Muscle Transfer The muscle is transected as far distal as possible from its insertion to the proximal tibia and transferred anteriorly so that it will have an almost direct line of pull. Because the semitendinosus has a type II vascular pattern, ligation of its distal vascular branches for its mobilization does not compromise the vitality of the muscle. The muscle and its tendinous part are then sutured to the patella and the remains of the quadriceps. Sartorius Muscle Transfer After completion of the resection, the sartorius muscle is released, but not transected, from its distal insertion on the medial aspect of the proximal tibia. The aim is to transfer the muscle anteriorly to the midline to achieve a straight line of pull between its origin on the anterior superior iliac spine and the patella. After ligating only two or three distal vascular branches, the sartorius can easily be transferred toward the midline and sutured to the patellar tendon, the patella, and the remains of the quadriceps tendon. Because the sartorius muscle has a type IV vascular pattern, care should be taken not to ligate more than three vascular branches to prevent distal flap necrosis.

P.353

PEARLS AND PITFALLS Indications

▪ Most tumors of the quadriceps arise within only one or two specific muscles (eg, vastus lateralis or medialis), so a partial resection of the quadriceps can often be done. ▪ Tumors that are close to the groin or the origin of the quadriceps require a careful dissection of the femoral triangle. ▪ The femoral triangle is rarely involved with quadriceps tumors. ▪ Tumors that arise close to the insertion of the quadriceps muscles may require an intra-articular resection and removal of a portion of the adjacent knee capsule. ▪ Tumors of the vastus intermedius may involve the underlying femur. The preoperative imaging studies must be carefully evaluated before an attempted resection. ▪ Tumors that arise within the vastus medialis muscle may extend and displace the sartorial canal. This should be determined preoperatively and mandates exploration and mobilization of the superficial femoral vessels and contents of the canal.

Reconstruction

▪ Large defects after quadriceps resection can be reconstructed using various muscle transfers primarily. If radiation therapy is planned postoperatively, it is best to postpone any transfers until the radiation is completed for optimal function of the transferred muscle.

POSTOPERATIVE CARE AND REHABILITATION Continuous suction is required for 3 to 5 days and perioperative intravenous antibiotics are continued until the drainage tubes are removed. If muscle transfer reconstruction was performed, a knee extension brace is initially used and an intensive physical therapy program for muscle strengthening and knee range of motion is started 3 to 4 weeks postoperatively. Weaning off the brace proceeds gradually in accordance with the

patient's functional improvement. No immobilization is required if only resection was carried out, and patients may gradually begin ambulation when the suction catheters have been removed. Because the lymphatics along the superficial femoral artery and within the buttock remain intact, prolonged swelling is not usually a problem.

OUTCOMES Patients who undergo limited resections of the quadriceps muscle usually do not have any residual functional limitations. There are limited data regarding the functional outcomes of patients who undergo extensive resections of the quadriceps muscle with or without reconstruction. Markhede and Stener5 evaluated the postoperative function in 17 patients who underwent quadriceps muscle resections. They found that the isometric strength of the muscle decreased by 22%, 33%, 55%, and 76% when one, two, three, or more components of the quadriceps muscle were resected, respectively. Capanna et al1 reported on the functional effect of quadriceps resection combined with distal femoral resection and prosthetic reconstruction in patients with malignant bone tumors. They concluded that the degree of quadriceps resection has a strong impact on functional outcome. Malawer4 performed a gait electromyographic analysis on a patient who underwent distal femoral resection, endoprosthetic replacement, and extensor mechanism reconstruction with the sartorius and biceps femoris muscles. Six months after the operation, both muscles were recruiting in phase with the rectus femoris of the same limb. According to our experience, most patients who undergo muscle transfer functional reconstruction have good to excellent functional outcomes and satisfactory active range of motion.7 Reported results of latissimus dorsi functional transplantation are likewise encouraging.2,3,8

COMPLICATIONS Wound dehiscence and infections may be associated with recent or ongoing postoperative radiation therapy and is easily managed by débridement, skin grafting, and vacuumassisted care. Vascular injuries rarely occur. Knee stiffness is the most common problem and is treated by physical therapy. Extensor mechanism weakness or dysfunction may result in falls and fractures. Pathologic femur fractures due to radionecrosis of the femur is a rare and devastating late complication.

REFERENCES 1. Capanna R, Ruggieri P, Biagino R, et al. The effect of quadriceps excision on functional results after distal femoral resection and prosthetic replacement of bone tumors. Clin Orthop Relat Res 1991;267:186. 2. Hallock GG. Restoration of quadriceps femoris function with a dynamic microsurgical free latissimus dorsi transfer. Ann Plast Surg 2004;52:89-92.

3. Ihara K, Shigetomi M, Kawai S, et al. Functioning muscle transplantation after wide excision of sarcomas in the extremity. Clin Orthop Relat Res 1999;358:140-148. 4. Malawer MM. Distal femoral osteogenic sarcoma: principles of soft-tissue resection and reconstruction in conjunction with prosthetic replacement (adjuvant surgical procedures). In: Lane J, ed. Design and Application of Tumor Prostheses for Bone and Joint Reconstruction. New York: Thieme-Stratton, 1983:297. 5. Markhede G, Stener B. Function after removal of various hip and thigh muscles for extirpation of tumors. Acta Orthop Scand 1981;52:373. 6. Mathes SJ, Nahai F. Vascular anatomy of muscle: classification and application. In: Mathes SJ, Nahai F, eds. Clinical Applications for Muscle and Musculocutaneous Flaps. St. Louis: Mosby, 1982:16. 7. Pritsch T, Malawer MM, Wu CC, et al. Functional reconstruction of the extensor mechanism following massive tumor resections from the anterior compartment of the thigh. Plast Reconstr Surg 2007;120:960-969. 8. Willcox TM, Smith AA, Beauchamp C, et al. Functional free latissimus dorsi muscle flap to the proximal lower extremity. Clin Orthop Relat Res 2003;410:285-288.

Chapter 30 Adductor Muscle Group (Medial Thigh) Resection Jacob Bickels Yair Gortzak Martin M. Malawer Yehuda Wolf

BACKGROUND The adductor compartment of the thigh is the second most common site for soft tissue tumors of the thigh, preceded by the anterior (quadriceps) compartment. Although resection of the muscular elements of this compartment does not considerably affect overall function of the lower extremity, the proximity of the major neurovascular bundle (NVB) of the lower extremity requires special attention in the preoperative evaluation process and during tumor resection. Tumors arising within the adductor compartment are often extremely large at presentation. As they enlarge, they often displace the superficial femoral and profundus vessels, and they may involve the extrapelvic floor musculature (obturator fascia) and bone (superior and inferior pubic rami and ischium) and even extend extracompartmentally to the medial hamstrings or the psoas muscle and the adjacent hip joint. These anatomic characteristics often make resection extremely difficult. Such large tumors were traditionally treated with amputation (ie, hemipelvectomy). Availability of effective chemo- and radiotherapeutic regimens has allowed the execution of limb-sparing resections at that site with low rates of local tumor recurrence. Lipomas and low-grade liposarcomas, which are the most common tumor type at that site, are usually removed easily with their enveloping capsule without having to manipulate the vascular bundle. High-grade soft tissue sarcomas, however, may grossly adhere to and surround the vascular bundle and require partial or complete resection of the involved bundle segment. Therefore, a limb-sparing tumor resection at that site begins with dissection and preservation of the superficial femoral vessels. Large high-grade sarcomas usually necessitate ligation of the profundus femoris artery. The surrounding adductors are then detached from their origin along the inferior and superior pubic rami and ischium and removed en bloc with the tumor. Reconstruction of the soft tissue defect remaining after tumor resection is usually done by transferring the sartorius muscle and the remaining medial hamstrings.

ANATOMY The adductor compartment of the thigh consists of the adductor magnus, brevis, and longus; the gracilis muscles; and the major vascular bundle of the lower extremity. Compartmental muscles arise from the pelvic floor and the medial aspect of the ipsilateral pelvic ring (symphysis pubis, inferior pubic ramus, ischium, and obturator fascia) and attach distally to the linea aspera and the medial aspect of the distal femur. The superficial femoral artery passes along the anterior and lateral margins of the entire compartment and forms the lateral border. This compartment is best thought of as an inverted funnel, with the base being the obturator ring and fascia, the lateral border being the femur and linea aspera, and the tip of the cone being the adductor hiatus (FIG 1).

INDICATIONS

Benign soft tissue tumors of the adductor compartment Soft tissue sarcomas of the adductor compartment

CONTRAINDICATIONS Approximately 95% of high-grade soft tissue sarcomas and almost all low-grade sarcomas of the adductor group can be safely resected. Today, amputation is rarely indicated. There are, however, several contraindications to limb-sparing surgery. In general, a combination of several contraindications is required, most of which are related to extremely large tumors. In those cases, we recommend induction chemotherapy or isolated limb perfusion and repeated staging studies before a definitive decision is made regarding amputation.2,3 Contraindications to limb-sparing surgery include the following: Major neurovascular involvement Pelvic floor involvement Extensive extracompartmental extension

IMAGING AND OTHER STAGING STUDIES Preoperative staging studies must evaluate the sartorial canal, pelvic floor, medial hamstrings, ischium, psoas muscle, and hip joint to determine the full extent of bone and soft tissue involvement; plain radiographs, computed tomography (CT), and magnetic resonance imaging (MRI) of the affected thigh, ipsilateral hip joint, and hemipelvis are indicated. Most adductor tumors displace the superficial femoral vessels but rarely directly involve these structures (FIG 2). The profundus femoris artery, on the other hand, is often involved and must be ligated as it passes through the adductor brevis. The obturator artery and nerve, which pass through the obturator fascia, are routinely ligated. In light of the earlier discussion, preoperative vascular evaluation of the patient should include direct questioning about intermittent claudication, limb swelling, and deep vein thrombosis. Vascular evaluation should include, in addition to physical examination, ankle-brachial pressure index and duplex ultrasound scanning of the femoral arteries and veins in the affected leg and of the greater saphenous vein in both legs. Underlying chronic obstructive arterial disease should prompt liberal use of angiography, CT angiography, or magnetic resonance (MR) angiography. Biplanar angiography, P.355 especially in patients older than 40 years of age, should be done to evaluate the patency of the superficial femoral artery: Ligation of the profundus artery without a patent superficial femoral artery will lead to a nonviable extremity.

FIG 1 • A. Anatomic structures of the adductor compartment. B. Crosssectional anatomy of the adductor group. The sartorial canal is opened. In the past, angiography was also used preoperatively to outline the course of the vascular bundle within the affected thigh and to assess the likelihood of vascular reconstruction. Highdefinition MR scans provide the same useful information. Availability of high-definition MR scans provides the same useful information. The bony structures of the pelvic floor are the closest margin for large sarcomas that arise within this muscle group. Occasionally, tumors arising from the pelvic ring require resection of the pelvic floor (type III pelvic resection) if negative margins are to be obtained in conjunction with a formal adductor group resection. Rarely, proximal adductor tumors may extend as a dumbbell around the ischium into the ischiorectal fossa. The possibility of such extension must always be evaluated preoperatively (FIG 3). The medial hamstrings also take their origin from the ischium. There is no intermuscular septum separating the adductor group from the posterior hamstrings proximally; therefore, extracompartmental extension may occur between the adductor muscles and the medial hamstrings as these tumors enlarge proximally. Adequate resection may require partial medial hamstring resection.

P.356

FIG 2 • A. CT showing large sarcoma of the proximal adductor compartment with displacement of the common femoral vascular bundle. Although the vessels are considerably displaced, a plane of dissection is evident between them and the tumoral mass. B. Positron emission tomography (PET) scanning is particularly useful in evaluation of sarcoma extension within the adductor compartment.

FIG 3 • A. Axial MRI showing a sarcoma of the adductor compartment. B. Coronal section showing a dumbbellshaped extension around the ischium into the pelvic cavity.

TECHNIQUES ▪ Incision and Exposure The incision extends from the proximal border of the inguinal region just inferior to the sartorius muscle and parallels the muscle to the posteromedial aspect of the knee to include the previous biopsy site (TECH FIG 1A). This incision permits large anterior and posterior flaps to be developed to visualize the

vastus medialis, the sartorial canal, and the entire adductor compartment. The incision can be extended to expose the popliteal space medially if required. The superior extent may have to be T'd along the border of the inferior pubic ramus if there is a large soft tissue component extending to the obturator fossa and ischium. Large anterior and posterior fasciocutaneous flaps are elevated and retracted anteriorly to expose the vastus medialis and the sartorial canal and posteriorly to the lower edge of the adductor muscle group (TECH FIG 1B,C). The biopsy site is left en bloc with the underlying adductor muscles. The sartorius muscle is the key to the dissection of the entire muscle group. The sartorial canal is opened proximally to identify the common femoral artery before ligating the profundus vessels. The muscles are detached from their origin (superior and inferior pubic rami) and along the obturator foramen. The dissection continues from proximal to distal: The obturator vessels, then the profundus femoral vessels, are ligated and transected (TECH FIG 1D,E). P.357

TECH FIG 1 • A. The incision extends from the proximal border of the inguinal region just inferior to the sartorius muscle and parallels the muscle to the posteromedial aspect of the knee to include the previous biopsy site. B,C. Large anterior and posterior fasciocutaneous flaps are elevated and retracted anteriorly to expose the vastus medialis and the sartorial canal and posteriorly to the lower edge of the adductor muscle group. D. Release of the adductor muscles from their insertions. The adductor magnus and longus are detached from their insertions on the femur throughout its length to the adductor hiatus. The adductor

magnus tendon is then transected distally. A finger is inserted into the adductor hiatus to guide the cautery and protect the underlying vessels. E. The surgical defect following resection. (Courtesy of Martin M. Malawer.)

▪ Tumor Resection Lipomas are removed with their enveloping capsules. Low- and high-grade sarcomas, however, require en bloc removal of an overlying cuff of adductor musculature (TECH FIG 2). Vascular involvement without a plane of dissection necessitates en bloc resection of the involved vascular segment (TECH FIG 3).

TECH FIG 2 • A. Axial MRI of the midthigh showing a well-differentiated liposarcoma of the adductor compartment. B. The tumor is well encapsulated and can be safely removed with a narrow cuff of adductor musculature. (continued) P.358

TECH FIG 2 • (continued) C. Completion of tumor removal. The remaining structures to be transected are the insertions onto the distal femur as well as portions of the gracilis muscle if required. The entire tumor is then removed and the wound is inspected. The superficial femoral artery and vein are inspected for any leaks. The cut edge of the muscles along the femur may be oversewn for hemostasis. If there is a large adductor tumor, occasionally, a portion of the proximal medial hamstrings must also be removed en bloc.

TECH FIG 3 • A. High-grade sarcoma of the adductor compartment extending into the superficial femoral vessels. Note the metal clip over the profundus femoral artery stump at the tumor bed. B. Blood vessels are suture-ligated and removed en bloc with the tumor. C. Gross surgical specimen. (C: Courtesy of Martin M. Malawer.)

▪ Vascular and Soft Tissue Reconstruction Resection of only a portion of the circumference of the artery for a short segment may be repaired by autologous vein patch. End-to-end anastomosis of a full circumferential resection is likely to be associated with considerable tension, and an interposition graft is required in those cases. Such reconstruction should preferentially be carried out with autologous tissue, primarily the greater saphenous vein (TECH FIG 4). It is best to use the vein from the contralateral thigh to preserve venous drainage as much as possible around the primary surgical site. This is particularly important when the femoral vein has to be ligated because of tumor extension around it or because of inadvertent injury. If the greater saphenous vein is inadequate or has been previously removed, the use of a prosthetic conduit is acceptable. Use of an arm vein graft, although more time-consuming, provides a better long-term solution. If the superficial femoral artery is chronically occluded, removal of the occluded segment is of no direct consequence. Careful intraoperative and postoperative evaluation of the profunda collaterals is mandatory; construction of a femoral popliteal bypass is done at the first sign of calf and foot ischemia. Reconstruction of the superficial femoral vein after en bloc resection with the tumor is more controversial. It is time-consuming and associated with high failure rates, even when a prosthetic material is used. Ligation is therefore a valid option in most of these cases. Prophylactic calf fasciotomy is strongly advised in patients in which superficial femoral arterial reconstruction and venous ligation were done and compromise of the venous collaterals is anticipated. The sartorius muscle is mobilized to cover the vascular bundle. Fasciocutaneous flaps are closed with

interrupted layers of sutures over suction catheters. P.359

TECH FIG 4 • Vascular reconstruction with autologous greater saphenous vein.

PEARLS AND PITFALLS Radiographic considerations

▪ Preoperative imaging of the entire adductor compartment and pelvic floor as well as detailed vascular evaluation

Intraoperative considerations

▪ Full exposure of the vascular bundle before tumor resection ▪ En bloc resection and reconstruction of affected vascular segments ▪ Prophylactic calf fasciotomy if arterial reconstruction and venous ligation were done

POSTOPERATIVE CARE Continuous suction is required for 3 to 5 days, and perioperative intravenous antibiotics are continued until the drainage tubes are removed. Full weight bearing is allowed as tolerated.

OUTCOMES Resections around the adductor compartment are usually associated with minimal loss of function. Limb edema, however, may occur in patients who had vascular reconstruction and venous ligation. Adjuvant

radiation therapy also increases the likelihood of chronic limb edema, which can be managed with lymphatic drainage. Patients who require a vascular reconstruction have similar rates of local tumor control and systemic relapse compared with patients who have not. However, these patients have higher chances of wound complications and deep vein thromboses.1

COMPLICATIONS Deep wound infection Vascular insufficiency Deep vein thrombosis Flap ischemia Local tumor recurrence

REFERENCES 1. Ghert MA, Davis AM, Griffin AM, et al. The surgical and functional outcome of limb-salvage surgery with vascular reconstruction for soft tissue sarcoma of the extremity. Ann Surg Oncol 2005;12: 1102-1110. 2. Gutman M, Inbar M, Lev-Shlush D, et al. High-dose tumor necrosis factor-alpha and melphalan administered via isolated limb perfusion for advanced limb soft tissue sarcoma results in a >90% response rate and limb preservation. Cancer 1997;79:1129-1137. 3. Henshaw RM, Priebat DA, Perry DJ, et al. Survival after induction chemotherapy and surgical resection for high-grade soft tissue sarcoma. Is radiation necessary? Ann Surg Oncol 2001;8:484-495.

Chapter 31 Hamstrings Muscle Group (Posterior Thigh) Resection Jacob Bickels Martin M. Malawer

BACKGROUND The posterior thigh (hamstring musculature) is the least common of the three compartments of the thigh for sarcomas to arise within. About 15% to 20% of the soft tissue sarcomas of the thigh arise within the posterior hamstring musculature. There is great variation in the size of tumors that occur in the posterior thigh, and the location varies from a proximal location near the ischium to a distal location involving the popliteal space. The posterior thigh is a quiet surgical area; the most significant structure is the sciatic nerve. Almost all low-grade sarcomas can be resected safely. Most high-grade sarcomas can be resected by either a complete or partial muscle group resection. The sciatic nerve is rarely involved, either because of direct tumor extension or because of a primary nerve tumor. En bloc resection of the sciatic nerve with a malignant tumor of the posterior thigh rarely is done; this has traditionally been considered an indication for amputation.2 This approach was based on the belief that the expected motor and sensory loss around the leg and foot would result in an intolerable functional deficit and the development of pressure sores and, therefore, high rates of secondary amputation. However, it has been shown that limb-sparing resection of the sciatic nerve is associated with a good functional outcome in most patients who have this procedure. Most patients were ambulatory; all used a short-leg brace because of the peroneal nerve palsy, but only half required a walking aid (crutches or a cane).1

ANATOMY The posterior compartment consists of the semimembranosus, the semitendinosus, and the long and short heads of the biceps muscles. All of these muscles originate at the ischium and the linea aspera. No major artery is involved with this compartment.

FIG 1 • Cross-sectional anatomy of the midthigh showing the extent of compartmental resection of the posterior thigh. The proximity of the sciatic nerve to large sarcomas within the posterior compartment is clearly indicated. (Courtesy of Martin M. Malawer.) The sciatic nerve is the most significant structure. It runs from the sciatic notch into the compartment from lateral to the ischium and divides the medial and lateral hamstrings. A thick sheath surrounds the nerve, acting as a barrier to direct tumor extension. Often, tumors arise within one of the individual muscles of the posterior thigh or between the muscles. In most cases, the sciatic nerve is displaced around an adjacent muscle.

INDICATIONS Almost all low-grade sarcomas of the posterior thigh can be treated by partial or total resection of the involved muscle. High-grade sarcomas are treated by complete myomectomy of the muscle involved. If the tumor is extramuscular but still remains within the compartment, a partial muscle group resection is performed (FIG 1). Multiple muscles or the entire compartment can be resected instead of an amputation. Contraindications for limb-sparing resections of the posterior compartment include the following: Extension into ischiorectal space: This makes the resection more difficult and may indicate the need for an amputation. Extension into the popliteal space with vascular compromise Femoral involvement with cortical destruction

IMAGING AND OTHER STAGING STUDIES Preoperative evaluation must include the ischium, the ischiorectal space, the retrogluteal area, and the popliteal space for tumor extension. The most useful imaging studies are computed tomography (CT) and magnetic resonance imaging (MRI). Angiography is required only if tumor extends distally into the popliteal space (FIG 2). P.361

FIG 2 • Axial (A) and coronal (B) magnetic resonance (MR) images of a myxoid liposarcoma of the posterior thigh. The tumor is extramuscular, arising in the space between the medial and lateral hamstrings. Clinical picture (C) and axial MR image (D) of a high-grade neurofibrosarcoma of the posterior thigh in a patient with an underlying neurofibromatosis. Café-au-lait spots are present on the patient's thigh. This is a primary tumor of the sciatic nerve and must be removed to obtain wide margins of resection.

TECHNIQUES ▪ Position and Dissection The patient is placed in a prone position. A long midline incision is used. An ellipse of skin is outlined so that there is a 2-cm margin of skin around the old biopsy site. The skin flaps are dissected, with care being taken to taper the flaps as one encounters the lateral margins of the dissection. The medial extent of the dissection is the gracilis muscle, and the lateral extent is the iliotibial tract (TECH FIG 1).

TECH FIG 1 • Illustration (A) and clinical photographs (B,C) showing the surgical incision. The extent of the tumor is outlined. (A: Courtesy of Martin M. Malawer.) P.362

▪ Skin Flaps and Exposure The medial (semitendinosus and semimembranosus) and lateral (long and short heads of biceps femoris) muscles are exposed (TECH FIG 2A,B). The extent of the dissection is determined by the location of the tumor, but it generally involves the long head of the biceps femoris, the semimembranosus, and the semitendinosus (TECH FIG 2C-F). It is possible for part of the lateral quadriceps mechanism to be included with the specimen.

TECH FIG 2 • A. Fasciocutaneous flaps are created and retracted to expose the contents of the posterior compartment. The biopsy scar is left on the tumor. B. Intraoperative surgical photograph following flap development and mobilization of the musculature and sciatic nerve. The large vascular tumor is obvious in the middle of the surgical field. C. Muscles of the posterior compartment after skin flaps have been raised. D. High-grade neurofibrosarcoma of the sciatic nerve extending into the overlying medial and lateral hamstrings, which are removed en bloc with the tumor. E. Extramuscular liposarcoma of the posterior compartment. This tumor is surrounded by a well-defined capsule, which allows sparing of the adjacent hamstrings. The latter can therefore be retracted with the fasciocutaneous flaps to expose the tumor. F. Soft tissue sarcoma contained within a pseudocapsule. The sciatic nerve is mobilized and preserved, and resection can proceed safely. (A,C: Courtesy of Martin M. Malawer.) Likewise, one or more muscle bundles of the adductor muscle group may be included if this will afford a more generous margin. The three muscles mentioned, which originate from the ischial tuberosity, are superficial to the sciatic nerve. With a tumor-free margin of resection on a tumor-free plane superficial to the posterior limits of this compartment, it is clear that the next adjacent structure is the sciatic nerve itself.

P.363

▪ Tumor Removal Benign and low-grade extramuscular tumors can be removed with their enveloping capsule (TECH FIG 3A). High-grade sarcomas or tumors that involve muscles of the posterior compartment, however, require en bloc muscle resection. Dissection begins by exposing the ischial tuberosity. It is easily identified on the skin surface. The hamstring muscles are released at their origin from the ischial tuberosity (TECH FIG 3B). Traction is then placed on the muscle group, which is secured with a clamp. Blood vessels and nerves that enter the hamstrings are ligated and divided. By blunt and sharp dissection, the sciatic nerve, the short head of the biceps laterally, and the adductor muscles medially are elevated from the base of the dissection (TECH FIG 3C). The lateral muscle insertion is then transected. The long head of the biceps femoris muscle is transected through its tendinous portion on the lateral aspect of the thigh.

TECH FIG 3 • A. The extramuscular liposarcoma shown in TECH FIG 2E can be safely removed without adjacent muscle tissue. B. Dissection and release of the hamstrings origin is the first stage of tumor removal. C. Tumor mass and enveloping muscles are elevated from the sciatic nerve and the base of the compartment by blunt and sharp dissection. ( B,C: Courtesy of Martin M. Malawer.)

Care should be taken to avoid injury to the common peroneal nerve. Sciatic Nerve Involvement If tumor grossly involves the sciatic nerve with no plane of dissection, the nerve is then resected (TECH FIG 4A,B). The insertions of the semimembranosus and semitendinosus muscles are then divided through their tendinous portion medially. The medial head of the gastrocnemius muscle is exposed (TECH FIG 4C-F). P.364

TECH FIG 4 • A. Tendinous insertion of the biceps femoris muscle on the lateral aspect of the thigh is transected. B. Sciatic nerve is grossly surrounded by high-grade sarcoma of the posterior compartment. No plane of dissection exists, and resection of the sciatic nerve is mandatory to achieve wide margins of resection. C. Tendinous insertion of the medial hamstrings is transected. (continued) P.365

TECH FIG 4 • (continued) D. Photograph of the posterior thigh after resection of an extramuscular liposarcoma. Posterior thigh musculature is preserved and retracted, and the tibial and common peroneal nerves are seen underneath. E. Posterior thigh after en bloc resection of a high-grade sarcoma with the overlying muscles and the sciatic nerve; only the semimembranosus muscle is left in the surgical field. F. Resection defect with preservation of the sciatic nerve. The semitendinosus and gluteus muscles have been preserved and retracted. (A,C: Courtesy of Martin M. Malawer.)

▪ Wound Closure The superficial fascia and skin are meticulously closed. Generous suction drainage is applied. The suction drains should not exit through the skin flaps but just above the gluteal crease (TECH FIG 5).

TECH FIG 5 • A. Closure of the surgical wound. B. Pathology specimen of resected hamstring. (A: Courtesy of Martin M. Malawer.)

P.366

PEARLS AND PITFALLS Preoperative

▪ Imaging of the posterior compartment, ischium, and ischiorectal space

Intraoperative

▪ Long midline incision ▪ En bloc removal of involved muscles and sciatic nerve, if necessary

Postoperative

▪ Use of short-leg brace and passive range-of-motion exercises

POSTOPERATIVE CARE A short-leg brace is applied and passive range-of-motion exercises are practiced immediately after surgery to avoid Achilles tendon shortening. Continuous suction is required for 3 to 5 days, and perioperative intravenous antibiotics are continued until the drainage tubes are removed. Full weight bearing is allowed as tolerated.

OUTCOMES Function after posterior thigh resection is almost normal: Knee flexion is maintained by the remaining sartorius, gracilis, and gastrocnemius muscles. Most patients who underwent en bloc resection of the sciatic nerve with a tumor of the posterior thigh were ambulatory; only half required a walking aid.1 All used a short-leg brace because of the loss of the peroneal nerve. Padded shoes are used to prevent pressure sores. Although all patients have an anesthetic ipsilateral foot, phantom limb pain, causalgia, pressure sores, and secondary amputation have not been documented.1 It seems that patients who had resection of the nerve at a lower anatomic level have better functional outcomes than patients whose resections involved a higher level. A possible explanation is that the innervation to the semimembranosus, semitendinosus, and long head of the biceps femoris is preserved in lower level resections.1

COMPLICATIONS Deep infection Flap ischemia and necrosis Sciatic nerve partial to complete dysfunction Local tumor recurrence

REFERENCES 1. Bickels J, Wittig JC, Kollender Y, et al. Sciatic nerve resection: is that truly an indication for amputation?

Clin Orthop Relat Res 2002;399:201-204. 2. Younge D, Paramasivan ON. Transtibial amputation for sciatic nerve loss: saphenous sensate residual limb. Clin Orthop Relat Res 1998;347:200-202.

Chapter 32 Overview of Surgical Resection of Space Sarcomas Amir Sternheim Tamir Pritsch

BACKGROUND The three main extracompartmental spaces of the lower extremities are the femoral triangle, the sartorial canal, and the popliteal space. Each of these spaces is confined by the bordering compartments of the lower extremity. All extracompartmental spaces have walls comprising the muscles and their fascia of the neighboring compartment, lumen, that is filled with fat, fibrous tissue, and vessels that traverse the space, namely, arteries, veins, and nerves. The distinction between intracompartmental and extracompartmental spaces was introduced by Enneking in his classification of soft tissue tumors as part of the Musculoskeletal Tumor Society (MSTS) surgical staging system more than two decades ago. Enneking borrowed the term extracompartmental from his classification of bone tumors. In that context, it refers to tumors that originate in the bone and then breach the cortex and have a soft tissue component. Extracompartmental tumors were considered to be more aggressive than their intracompartmental counterparts and therefore harder to treat and with a worse prognosis, although this has changed in recent years. The original soft tissue sarcoma (MSTS) staging system had three prognostic criteria: metastasis, grade, and compartmentalization. The term compartmentalization divides soft tissue sarcomas into intracompartmental and extracompartmental tumors. Intracompartmental lesions are bound in all directions by natural barriers such as bone and muscle. These tumors arise within a structure—thigh: anterior, adductor, posterior; leg: anterior, peroneal, posterior superficial, posterior deep. In contrast, extracompartmental tumors either arise in spaces that are not bound by tight muscle fascia as compartments are (ie, popliteal space, sartorial canal, femoral triangle, axilla, antecubital fossa, paraspinal, intrapelvis, midhand, midfoot, and hindfoot) or develop secondary to the extension of an intracompartmental tumor beyond the confines of a compartment. Extracompartmental tumors have unique characteristics. They can extend a considerable distance with less anatomic restraint. They frequently arise in close proximity to the neurovascular bundle. For these reasons, space tumors were initially considered to have a poorer prognosis than those confined to a compartment at diagnosis. Newer prognostic studies of soft tissue sarcomas do not support the assumption that space tumors have a worse prognosis due to their location but rather due to their size. Space tumors have been poorly addressed in Enneking's classification and in the later American Joint Committee on Cancer (AJCC) classification. The classification of an intracompartmental lesion was based on tumor biology. Extracompartmental tumors were originally tumors that grew from within a compartment outward and into an adjacent compartment. Only later was the definition broadened to include space tumors. Since then, these space tumors have been poorly discussed in terms of their anatomy, biology, and surgical approach. The newer version of the AJCC classification for the staging of soft tissue sarcomas does not use compartmentalization as a staging criteria but rather tumor grade, size, and depth. Resection goals for soft tissue sarcomas of the extremities are wide resection of the lesion with negative

resection margins and satisfactory extremity function. With intracompartmental tumors, these goals are achieved by resecting the tumor with the muscle that surrounds it. Space tumors lie in proximity to vessels and nerves, so achieving wide resection of the tumor without resecting the vessels is a delicate task. Some tumors, although in intimate proximity to the vessels, may still be resected with negative margins, whereas other tumors behave differently and invade the vessels. Vessel invasion dictates vascular resection. This biologic difference in tumor behavior is dictated by tumor grade, size, and biology. Different tumors, due to their different biology, dictate different surgical resection techniques. Unlike intracompartmental tumors, space tumors differ vastly from one tumor to the next in the amount and technique of resection needed. Guidelines for resecting the different types of space tumors are lacking.

ANATOMY Femoral Triangle Space The femoral triangle can be depicted as a three-dimensional pyramid. The base is the inguinal ligament, bound laterally by the sartorius and medially by the medial edge of adductor longus or the anterior border of gracilis (FIG 1). The floor of the femoral triangle is the iliopsoas laterally and the pectineus and adductor longus medially. Its apex is where the sartorius crosses over to the adductors. The main vessels traversing the canal are, from medial to lateral, the femoral vein, artery, and nerve. They enter the femoral triangle from the abdomen under the inguinal ligament and exit it distally from the tip of the pyramid into the sartorial canal.

Sartorial Canal The sartorial canal lies between the anterior (quadriceps) compartment and the medial adductor compartment, connecting the tip of the femoral triangle in the proximal thigh P.368 to the popliteal fossa in the distal posterior aspect of the thigh. The cross-section of the sartorial canal is shaped like an inverted triangle (FIG 2).

FIG 1 • Cross-sectional anatomy of the lower extremity spaces. A. Femoral triangle anatomy follows the general outline of a three-dimensional pyramid. The vessels within the space from medial to lateral are the femoral vein, artery, and nerve. The femoral triangle has as its base the inguinal ligament; it is bound laterally by the sartorius and medially by the medial edge of adductor longus and the anterior border of gracilis. The floor of the femoral

triangle is the iliopsoas laterally and the pectineus and adductor longus medially, and its apex is where the sartorius crosses over to the adductors. B. Popliteal space anatomy follows the general outline of a threedimensional diamond shape. The biceps femoris, semimembranosus, lateral gastrocnemius, and medial gastrocnemius muscles form the four walls of the space. The popliteal artery and vein lie deep in the space, whereas the sciatic nerve is more superficial. The deep fascia serves as a barrier between the space and the superficial tissue. The roof of the canal is made up of the sartorius muscle, which lies anterior and medial to the canal. The adductor longus makes up the floor of the canal. The lateral border is the thick fascia of the vastus medialis. Posteriorly, the border of the canal is the adductor compartment, namely, the adductor magnus. Both the posterior and lateral borders are also covered with thick fascia. The superficial femoral artery and the femoral vein enter the canal proximally through the tip of the femoral triangle. These structures lie deep in the canal and are surrounded throughout their length by a very thick fascial sheath. The vessels exit the canal at the distal-medial end through the adductor hiatus, a foramen in the distal part of the adductor magnus.

Popliteal Space The popliteal space is shaped like a three-dimensional diamond. On its proximal-lateral side is the biceps femoris muscle. On the proximal-medial side are the semitendinosus and semimembranosus muscles. On the distal side of the space are the lateral and medial heads of the gastrocnemius muscles (see FIG 1B). Anterior to the space is the posterior capsule of the knee joint. Posterior to the space is a thick popliteal fascia. Vessels of the popliteal space are the popliteal artery and vein, which enter proximally through the adductor hiatus and exit distally between the two heads of the gastrocnemius. The sciatic nerve enters the space through the proximal tip and divides into the peroneal and tibial nerve branches.

INDICATIONS A set of surgical guidelines is a helpful clinical conceptual tool in resecting lower extremity soft tissue sarcomas from the three anatomic spaces. Using preoperative magnetic resonance imaging (MRI) and initial intraoperative impressions, tumors may be divided into three groups. Tumors are divided according to their location of origin. Type 1 tumors arise from within the space. Typically, they originate from fat or fibrous tissue within the space. These tumors are termed luminal because they may approximate but do not adhere to the walls of the space or any of the arteries, veins, and nerves in the space. They lie within the lumen. Type 2 tumors arise from one of the walls that border the space. These tumors arise from within a muscle or the muscle fascia that borders the space. Type 3 tumors invade the arteries, veins, or nerves and are termed vessel lesions. These lesions either originate from or invade the vessels walls. The surgical planes of resection differ for each of the three types: Type 1 (luminal) lesions are resected with a thin cuff of healthy tissue that surrounds the tumor. At times, these tumors almost deliver themselves once the space is opened. Tumor margins, although negative, are often close. Type 2 (wall) lesions are essentially resected with the muscle from which they originate. Wide surgical

resection is achieved by resecting the tumor with its muscle of origin and the fascia covering that muscle. Tumors that approximate the vessels and are adherent to the vessel sheath are resected with the vessel sheath as an oncologic barrier and should be approached in the following manner. On approaching the tumor area, if the sheath appears free and separates easily from the wall of the artery, the surgeon continues the dissection, leaving the P.369 sheath attached to the surface of the specimen by making an incision in the sheath on the side away from the tumor and extricating the artery (and vein if possible) from its sheath.

FIG 2 • Systematic resection of extracompartmental space tumors. The left column shows axial MR images of the three different types of tumors in the sartorial canal. The middle column shows a schematic of the tumor location. The right column shows the recommended planes of surgical resection (dotted line). Resection types 1 to 3 are presented in the rows from top to bottom. Type 1 (intraluminal) tumors lie within the space and are resected with a thin cuff of surrounding tissue. Type 2 (wall) tumors arise from the muscles surrounding the space and are resected as a typical muscle resection. Type 3 (vessel) tumors invade the vessels and are therefore resected en bloc with the vessels. The fibrous sheath surrounding the vessels is inspected carefully on frozen section after it has been removed en bloc with the tumor. Even when the tumor does not adhere to the vessel sheath, it should be

removed separately from the tumor so that it can be examined to rule out tumor invasion through the sheath, thus ensuring safe resection margins. Type 3 (vessel) tumors are embedded in the vessel wall. When it is clear that the vessels are involved, the surgeon establishes vessel control proximally and distally and works around the tumor widely all the way around until the soon-to-be specimen is tethered by the vessels proximally and distally. The surgeon then chooses the grafts to be used, administers heparin, and applies vascular clamps proximally and distally. The specimen is removed, fol lowed by reconstruction. This circumferential freeing of the tumor and the normal tissue margin is the essential difference between space tumors involving the vessels and those not involving them, a difference in surgical strategy. After the artery is resected, it must be reconstructed with a synthetic graft or a reverse saphenous vein graft. Venous resection does not need to be reconstructed as long as the ipsilateral saphenous vein is intact. Potential morbidity from venous resections arises from the risk of edema in the affected limb. Nerves invaded by tumor must be resected en bloc (namely, sciatic, femoral, tibial, and peroneal). These nerve resections do not dictate a need for amputation but can be treated with limb-sparing surgery. As the tumor is resected en bloc with the vessel, these resections, although challenging surgically in their reconstructive aspects, are relatively straightforward in their tumor resection aspects and can achieve wide surgical margins.

P.370

IMAGING AND OTHER STAGING STUDIES Plain Radiography Plain radiography studies are performed to rule out local invasion of the bone by the tumor.

Computed Tomography and Magnetic Resonance Imaging These studies are used to assess the anatomic location and size of the tumor and its relation to surrounding structures. These studies are particularly important because the tumor often distorts the normal anatomy in these small, tight spaces. Arterial contrast and three-dimensional reconstruction enhance these studies even further. MRI is useful in assessing the tumor's invasion into neighboring anatomic structures, namely, the muscles bordering the canal and the vessels traversing the canal.

Bone Scanning Bone scan is used to rule out distant metastatic disease and may give a clue to the malignancy of the tumor, as highgrade tumors show a strong tumor blush in the late arterial flow phase of the three-phase technetium scan.

Angiography and Other Studies Angiography is used to assess the vascularity of the tumor, tumor blush, the location of the vessels feeding the tumor, and the relation between the tumor and the major artery and vein, giving vital information whether the tumor has displaced or invaded the vessel. Venography of the limb is used to rule out venous thrombus, tumor thrombus, or direct tumor involvement.

Biopsy

Core needle and open incisional biopsy give vital information about the tumor. The proximity of these tumors to major vessels adds an additional risk factor for both iatrogenic damage to the vessels and contamination of the space with tumor cells due to hematoma. We prefer a small needle biopsy and a fine needle aspiration. It is most important to determine whether the tumor is a lymphoma or a mesenchymal tumor (soft tissue sarcoma). Lymphomas do not require surgical resection. The exact histogenesis is not required if it is a soft tissue sarcoma because resection margins are usually more defined by the anatomy than the actual surgical procedure. However, it is important to determine the grade (high or low) because neoadjuvant chemotherapy may be recommended.

SURGICAL MANAGEMENT Wide exposure of the space is critical. The space must be unroofed by retracting and at times detaching the overlying muscle. Initially, critical vessels should be identified and controlled proximally and distally to the tumor, where the anatomy has not been distorted. Tumor is resected in a circumferential manner with wide margins when possible. When the lesion is in intimate proximity to the vessels, the sheath of fibrous tissue surrounding the vessels should be resected en bloc with the tumor unless it is evident that it has not been invaded. The vessel sheath should be opened from the opposite side of the tumor to assess whether tumor that adheres to the sheath has invaded the vessel wall as well. Tumor that invades the vessels must be resected with the vessels, which then need to be reconstructed. When the tumor does not seem to grossly invade the vessels, the sheath that has been resected en bloc with the tumor should be examined on frozen section to rule out microinvasion. Soft tissue reconstruction is done by moving adjacent muscle to cover the vessels. This is essential. If there is later wound breakdown, the vessels must have good vascularized soft tissue coverage. Reconstruction with rotational muscle flaps or free vascularized flaps is strongly recommended.

Preoperative Planning Preoperative MRI and computed tomography (CT) and possible three-dimensional CT angiography are useful to identify the exact size and location of the tumor. This will help in classifying the type and thus in choosing the type of surgery that is required. Contrast CT is important to determine accurately the position of the artery within the specific space. Often, the artery is greatly displaced from the normal anatomic relationships. In the popliteal space, the artery is often displaced anterior to the tumor, whereas the sciatic nerve (tibial and peroneal branches) is often displaced in the opposite direction (ie, posteriorly and or laterally). In addition, the decrease in tumor blush from the initial angiogram and the final one after induction chemotherapy (for high-grade sarcomas) correlates well with the percentage of tumor necrosis. If there is a good angiographic response, then a marginal resection is very reasonable. Venography: The major veins may be occluded due to pressure of the soft tissue mass or invasion of the vascular sheath, and therefore by inference, the major artery or nerves may be involved by tumor. Venous grafts are often not performed because most will not remain patent. Neurologic examination: Involvement of a major nerve within a space often presents with severe pain or motor weakness. This should suggest to the surgeon that the major nerve may have to be sacrificed. In general, femoral nerve (femoral triangle) or sciatic nerve (popliteal space) involvement is not a sole indication for

amputation.

Positioning Femoral triangle (space): A supine position is used. The abdomen and the thigh must be prepared together. It is sometimes necessary to begin the exploration of the femoral vessels retroperitoneally to identify and to place a vascular loop around the external iliac artery and vein for proximal control. Sartorial canal: The patient is placed supine and the lower extremity is flexed and rotated externally at the hip. The entire thigh, lower pelvis, and leg are prepared so that the distal pulses can be palpated (or assessed using Doppler). Popliteal space: The patient is placed prone. The posterior thigh from above the gluteal crease to the foot is prepared free. This provides good exposure to the retrogluteal area, the posterior thigh (if the tumor extends proximal from the P.371 space), the popliteal space, and the leg (calf) if the tumor extends distal to the popliteal space, specifically below or between the gastrocnemius muscles.

Approach Femoral triangle: The incision begins proximal to the inguinal ligament as a gentle S and crosses the inguinal ligament. It then proceeds distal to the tip of the femoral triangle to the proximal portion of the sartorial canal. The incision somewhat parallels the medial border of the sartorius muscle. The major vessels are located proximal and distal before any attempted resection. Sartorial canal: The incision follows the sartorius muscle from the apex of the femoral triangle to the level of the adductor hiatus. If necessary, the incision may be extended to include the popliteal space (if the tumor is distal in the canal) or proximal (if the tumor is located proximal in the canal and extends into the femoral triangle). The sartorius muscle is mobilized either anteriorly or posteriorly along its borders (as long as the sartorius is not involved with tumor). Segmental pedicles to the sartorius muscle may be ligated. If the sartorius muscle is involved, then the muscle is transected proximal and distal to the tumor for exposure before resection.

TECHNIQUES ▪ Tumors of the Femoral Triangle The femoral triangle is exposed through a longitudinal incision that curves over the inguinal ligament and extends to the sartorial canal. The external iliac vessels (retroperitoneal) are exposed, and a vessel loop is placed around them (TECH FIG 1). Wide subcutaneous skin flaps are made above the femoral triangle fascia to permit identification of the tumor, sartorius muscle, and adductor fascia. The proximal end of the sartorial canal is opened, and the superficial femoral artery and vein are located to gain distal control. The deep fascia of the canal is opened, exposing the tumor. The tumor is explored and its surgical type is determined. Its relationship to the femoral nerve and femoral vessels is assessed. This will define which structures need to be resected and which can be preserved. If a vascular graft is required, either Gore-Tex or contralateral saphenous vein can be used. If the femoral nerve is resected, medial and lateral hamstring transfers are performed at a second stage after wound healing or radiotherapy. The tumor is resected with surrounding fat, lymphatics, and any necessary muscle.

Hemoclips are placed around the surgical bed. The sartorius muscle is routinely detached from the anterior superior iliac spine and rotated to cover the remaining defect and neurovascular structures. The sartorius muscle is tenodesed to the inguinal ligament and the remaining adjacent musculature. The skin flaps are then closed. A flat drain is placed deep to the muscle transfer.

TECH FIG 1 • Intraoperative image of a type 3 resection of a leiomyosarcoma arising from the femoral vessels. Proximal and distal control of the involved vessel is crucial. A vessel loop is placed on the external iliac artery (marked vessel). The spermatic cord is tagged and mobilized. (A) The skin incision and the surgical approach follow the line of the inguinal ligament and sartorius muscle. (B) The sartorius muscle is detached proximally to allow better exposure and soft tissue reconstruction. (C) Soft tissue is reconstructed by fanning out the sartorius muscle, thus achieving a muscle barrier between the femoral vessels and the skin. P.372

▪ Tumors of the Sartorial Canal The incision follows the course of the sartorius muscle. It may be extended proximally (femoral triangle) or distally (popliteal space) as required (TECH FIG 2). Wide subcutaneous flaps are elevated off the deep fascia to expose the anterior and posterior borders of the sartorius muscle. The sartorius muscle is then mobilized either along the anterior interval with the vastus medial muscle or posteriorly along the adductor interval. If the sartorius muscle is not involved by tumor (based on the preoperative MRI), the muscle is usually

preserved. The sartorial canal is explored both proximal and distal to the tumor mass to identify the superficial femoral artery and vein. If the saphenous nerve is encountered, it may be sacrificed. Tumor resection is then performed according to the type of tumor. Type 1 (intraluminal) tumors usually require only a simple marginal excision. If the tumor approaches the vessels, then the sheath is removed and sent for a frozen section examination. If no tumor is present at this margin, the sartorius flap is then closed. For a type 2 tumor, the initial approach is similar to that described earlier, except the tumor's muscle of origin must also be resected. This is often a portion of the sartorius muscle or the vastus medialis. Tumors involving the adductor muscles are less common. Resection of the adjacent vascular sheath is routinely performed, similar to type 1 tumors. Type 3 tumors often arise from the vascular sheath. The initial approach is similar to that for types 1 and 2 but also involves resection of the superficial femoral artery and vein. The vascular surgeons perform this portion of the operation. The artery must be reconstructed, either with a Gore-Tex graft or the ipsilateral saphenous vein. Heparinization may be required.

TECH FIG 2 • Type 2 resection of a tumor of the sartorial canal arising from the wall (vastus medialis) that comes in close proximity of the vessels. Even so, the tumor was resected and the vessels were spared, as it did not penetrate the fascial sheath surrounding the vessels. (A) The skin incision is carried along the sartorius muscle. The sartorius is resected with the tumor if necessary from an oncologic point of view. If the tumor is not connected to the sartorius muscle, it may be disconnected distally for exposure. (B) Soft tissue reconstruction with a gracilis muscle transfer affords good soft tissue coverage of the vessels of the sartorial canal and is considered crucial. The distal end of the gracilis muscle is disconnected and rotated anteriorly. The muscle is then spread out like a fan and reattached anteriorly.

▪ Tumors of the Popliteal Space

A “lazy S” incision is made over the popliteal space. The medial arm is always made along the medial border of the medial hamstrings because the popliteal vessels come into the space medially from the adductor hiatus (TECH FIG 3). The lateral arm of the incision is made along the lower border of the biceps femoris muscle because the peroneal nerve is initially picked up just below the deep fascia as a satellite of the biceps muscle. Wide subcutaneous flaps are made exposing the deep popliteal fascia. Great care is taken not to penetrate this fascia early because it is easy to get lost in the popliteal fat. The peroneal nerve is first identified just medial to the biceps muscle, just under the deep fascia. The deep fascia is then opened longitudinally, and the sciatic nerve is identified between the medial and lateral hamstrings. The four muscles that make up the “diamond” of the popliteal space are now identified: the medial and lateral hamstrings proximally and the medial and lateral gastrocnemius muscles distally. The midline of the gastrocnemius muscles is identified. The popliteal vessels and the tibial nerve are mobilized, and a vessel loop is placed around them for distal control. The sciatic nerve is then mobilized, both the peroneal and the tibial nerve components. The popliteal artery and vein are identified proximally near the medial hamstrings deep in the fossa as they enter from the adductor foramen. The surgeon can easily feel the pulse (a tourniquet should not be used), and a finger can be safely placed into the adductor hiatus for localization. Careful dissection and mobilization of the vascular and nerve structures are then performed. P.373

TECH FIG 3 • Large popliteal type 1 resection of a luminal tumor. Intraoperative picture shows wide exposure of the popliteal space. The tumor is in close proximity to the sciatic nerve above it and the popliteal artery and vein just below it (vessel loops). As it is a luminal tumor, resection with negative margins was achieved without resection of the surrounding vessels. (A) Skin incision and subcutaneous flaps necessary to permit exposure. Care should be taken not to open the popliteal fascia while developing the flaps to reduce the risk of neurovascular injury. (B) Release of the gastrocnemius heads, which are then reflected distally for maximal exposure. The popliteal vessels are identified distally between the gastrocnemius heads. (C) Tenodesis of the heads of the gastrocnemius and the hamstring muscles, forming a muscular coverage over the popliteal vessels and nerves. The medial or lateral head, or both, of the gastrocnemius muscles may be released from their origins on their respective femoral condyles to help in the exposure. Similarly, the semimembranosus or biceps femoris muscle may be released for better exposure. If the tumor extends proximally (between the hamstrings or distally between the gastrocnemius muscles), then the corresponding muscle must be released to obtain a wide excision. The popliteal vessels are usually displaced and not involved by tumor, unless a leiomyosarcoma is arising

from them. In this situation, a vascular graft is required. The tumor is resected only after all of the aforementioned structures are identified and mobilized. Sheaths of the adjacent nerves or vessels are removed and sent for frozen section examination to determine whether further resection is required. Soft tissue closure is necessary to cover and fill the popliteal space to prevent wound problems. The medial and lateral gastrocnemius heads are tenodesed to each other, covering the distal portion of the popliteal space and the neurovascular structures. Similarly, the medial hamstrings are tenodesed to the biceps femoris muscle to close over the proximal popliteal space. Both the gastrocnemius and the hamstrings are then sutured together to make a nice muscle closure of the entire popliteal space.

P.374

PEARLS AND PITFALLS Preoperative classification of the type of space tumor is essential.

▪ Tumors are classified as types 1, 2, or 3 (discussed earlier). Classification will suggest the planes of resection and the structures to be removed.

CT and MRI are essential.

▪ CT and MRI are used to identify the local anatomy and to determine the type of tumor.

Angiography

▪ Angiography determines the anatomic position and probable displacement of the major vessels passing through the space.

Type 3 resections

▪ In type 3 resections, the major vessel must be resected and reconstructed. Heparinization may be required postoperatively. Venous reconstruction is usually not recommended.

Vascular control

▪ Always obtain proximal and distal control of the major vessels before approaching or resecting the tumor.

Neurologic examination of femoral and sciatic nerve function

▪ Any motor weakness almost always indicates tumor involvement of the major nerve.

POSTOPERATIVE CARE Pulses are checked hourly for the first 24 hours. Drains are removed on postoperative day 2 or 3. Full weight bearing is permitted within 1 to 2 days. Minimal rehabilitation is required. Motion is limited according to the anatomic space for 7 to 10 days to permit complete wound healing. Popliteal incisions are protected with a bent-knee brace until the wound is well healed. Postoperative radiation therapy is started only after the wound is well healed, between 2 and 4 weeks.

OUTCOMES We have treated 53 patients with space tumors. Malignant fibrous histiocytoma and liposarcomas are the most common. A classification system was developed as described earlier. Most sartorial tumors tend to be of low grade and involve the wall; the sartorius muscle is most often involved. Liposarcomas and, secondarily, malignant fibrous histiocytomas were the most common histogenic types. Tumors involving the wall of the space were more common than those that are intraluminal or those that arise from the major neurovascular structures. Tumors arising from the major vessels were leiomyosarcomas.

Popliteal tumors, often high grade, can be dissected with negative margins and followed by radiation therapy. Sciatic nerve resection is very unusual. Amputation for all space tumors is needed in less than 10% of cases and is usually reserved for tumors that locally recur. The overall survival depends on the grade. Local recurrence is less than 10% for all sites. Radiation therapy is used for all high-grade sarcomas after wound healing. The surgical classification has been implemented on 53 patients with soft tissue tumors of the lower extremity spaces (femoral triangle, sartorial canal, and popliteal fossa).

COMPLICATIONS The most common problem is wound or flap necrosis. This is more common in the popliteal space. Incisions of the femoral triangle or the sartorial canal heal well. Neurapraxia, especially of the peroneal nerve, is common but function almost always returns. Infection is unusual. Preoperative radiation is not used due to the risk of wound dehiscence or necrosis. Secondary amputations occur in less than 5% to 10% of patients, often after local tumor recurrence.

SUGGESTED READINGS 1. Bickels J, Malawer MM. Resections in the popliteal fossa and the posterior compartments of the leg. In: Malawer MM, Sugarbaker PH, eds. Musculoskeletal Cancer Surgery: Treatment of Sarcomas and Allied Diseases. Philadelphia: Lippincott Williams & Wilkins, 2001:chap 16. 2. Pritsch T, Bickels J, Winberg T, et al. Popliteal sarcomas: presentation, prognosis, and limb salvage. Clin Orthop Relat Res 2006;455:225-233. 3. Wu CC, Pritsch T, Shehadeh A, et al. The anterior popliteal approach for popliteal exploration, distal femoral resection, and endoprosthetic reconstruction. J Arthroplasty 2008;23:254-262.

Chapter 33 Popliteal Resections Amir Sternheim Yair Gortzak Jacob Bickels

BACKGROUND Soft tissue sarcomas of the popliteal fossa are rare, accounting for less than 5% of all soft tissue sarcomas of the extremities. Surgery in this anatomic area is challenging: Performing a wide resection with negative surgical margins is often difficult because of the periarticular location and the proximity to neurovascular structures.3,7,10 Such tumors formerly were treated with amputations4; however, better understanding of tumor biology and advances in chemotherapy and radiation therapy now allow limb-sparing procedures to be performed in most of these cases.

ANATOMY The popliteal space is diamond-shaped; on its superior aspect, it is bounded by the semimembranosus and semitendinosus muscles medially and by the biceps femoris muscle laterally. Its inferior boundaries are the two heads of the gastrocnemius muscle. The roof of the fossa is the thin popliteal fascia; the floor is the posterior aspect of the distal end of the femur, the posterior capsule of the joint, and the popliteus muscle, which overlies the proximal tibia. The popliteal artery and vein enter the popliteal space from its medial aspect through the adductor hiatus and lie directly behind the posterior capsule of the knee joint. They run obliquely through the fossa and branch into two superior, a single middle, and two inferior genicular branches. After exiting the popliteal fossa, the popliteal artery divides into its terminal branches: the anterior tibial, posterior tibial, and peroneal arteries. The popliteal vein lies between the tibial nerve and the popliteal artery. The short saphenous vein pierces the popliteal fascia to join the popliteal vein within the fossa.

FIG 1 • MRI of a typical popliteal sarcoma. A. Normal MRI of the distal section of the popliteal (diamond) space

through the medial and lateral gastrocnemius muscle insertions onto the femoral condyles. B. Large popliteal soft tissue sarcoma. (continued)

FIG 1 • (continued) C. Sagittal view showing the relationship of a popliteal sarcoma to the adjacent femur and knee joint (not involved in this case). D. Angiogram of an extremely vascular popliteal sarcoma. Arterial embolization may be useful. All of the small pedicles to the tumor must be ligated at the time of resection. The popliteal artery is rarely involved directly and is often preserved. E. CT angiogram demonstrating displacement of the popliteal artery. The tibial nerve enters the popliteal fossa lateral to the popliteal artery and approximately in the middle of the fossa. It crosses the artery to its medial aspect and remains at that location. The common peroneal nerve slopes down the superolateral border of the popliteal fossa toward the medial aspect and along the biceps femoris tendon, where it enters a tunnel within the substance of the peroneus longus muscle.

IMAGING AND OTHER STAGING STUDIES Magnetic Resonance Imaging Magnetic resonance imaging (MRI) is the imaging modality of choice for the diagnosis of popliteal soft tissue sarcomas. The typical finding is a soft tissue mass with a solid component, no communication to the knee, and central or irregular nodular gadolinium enhancement. Conversely, the classic presentation on MRI of popliteal cysts, which are the most frequently encountered masses in the popliteal fossa, is a well-defined, unilocular,

fluid-filled cyst in direct communication with the knee joint; its peripheral walls are normally enhanced with gadolinium. MRI is also used to evaluate the size of the tumor and its relation to the neurovascular structures, the posterior knee joint capsule, and surrounding musculature and to assess local lymph node involvement (FIG 1A-C). P.376

Plain Radiography and Computed Tomography Plain radiography and computed tomography (CT) scans are performed to rule out invasion of the tumor into the adjacent bones.

Angiography Angiography (FIG 1D-E) is routinely used to assess the relation of the tumor to the popliteal artery, patterns of possible vascular displacement, the presence of vascular anomalies, and arterial and venous patency.

FIG 2 • Clinical photograph of a large popliteal sarcoma. A prone position is routinely used for surgical resection.

SURGICAL MANAGEMENT Positioning The patient is placed in the prone position (FIG 2) and both lower limbs are draped. The contralateral leg is prepared for saphenous vein harvesting, which will be necessary for arterial reconstruction if the popliteal artery must be resected. P.377

TECHNIQUES ▪ Exposure An S-shaped incision is made, crossing from proximal-medial to distal-lateral at the level of the knee joint (TECH FIG 1A). The medial-proximal arm of the incision allows the popliteal vessels to be identified as they exit the adductor hiatus, and the lateral distal arm enables easy exposure of the peroneal nerve, posterior to the fibular head. In addition, making the distal arm of the incision lateral avoids damaging the greater saphenous vein, which runs on the medial aspect of the leg (TECH FIG 1B).

TECH FIG 1 • A. Incision used for resection of popliteal sarcomas. A wide exposure of the popliteal (diamond) space must be obtained to avoid inadvertent injury to important neurovascular structures. B. The medial and lateral hamstrings are mobilized and retracted with a wide self-retainer retractor. Similarly, the medial and lateral gastrocnemius heads are detached from the femoral condyles, retracted, or both. The two heads of the gastrocnemius muscles are split at the midline, taking care not to injure the now more superficial tibial nerve and vessels (located just anterior to the nerve). The very thin and friable popliteal fascia lies in close proximity to the neurovascular bundle (especially the peroneal nerve, which lies just deep to the popliteal fascia at the level of the fibular head), making it a critical landmark. To identify the popliteal fascia, subcutaneous flaps are made. The landmarks and various structures of the popliteal fossa can often be palpated through the fascia, which is then cautiously incised accordingly. Failure to realize that the dissection is underneath the fascia and that only a few millimeters separates the blade from the vessels and nerves of the popliteal fossa can easily result in injury of those structures. The short saphenous vein runs superficial longitudinally along the midline from the posterior calf and enters the popliteal fascia to join the popliteal vein. It serves as a landmark and following it proximally is a safe technique that helps identify the vascular structures of the popliteal fossa.

▪ Tumor Resection The initial step of a popliteal fossa resection is exposure and identification of the neurovascular bundle.

This allows the surgical team to mobilize the vulnerable structures before resection. Mobilization is usually accomplished by exposing the structures in the distal thigh and proximal leg and following them to the popliteal fossa (TECH FIG 2A,B). If the popliteal vessels are difficult to expose, an intraoperative Doppler ultrasound device can be helpful. After mobilizing the neurovascular bundle, the tumor is resected with a cuff of normal tissue if possible. Not uncommonly, however, the vessels, the nerves, or both are in close proximity to the tumor mass or adherent to its pseudocapsule. In such cases, the structures are dissected free and the nerve sheath and adventitia are removed and pathologically examined using frozen sections to determine the surgical margins (TECH FIG 2C,D). Vessels and nerves of the popliteal fossa must be resected if they are embedded in the tumor mass. All of the pedicles from the gastrocnemius to the tumor should be resected (TECH FIG 2E). The popliteal artery can be reconstructed with a saphenous vein graft taken from the contralateral leg. We consider reconstructing the popliteal vein to be unnecessary because the ipsilateral saphenous vein can compensate for its loss. Nerve involvement or vascular involvement is not an indication for primary amputation if these features can be adequately resected.1,2,5 P.378

TECH FIG 2 • A. The sciatic nerve is identified, as well as its two major branches, the tibial and peroneal nerves. B. Posterior exposure of the popliteal space following release of the lateral head of the gastrocnemius with demonstration of an extra-articular sarcoma in relation to the labeled anatomic structures. C. Lateral intraoperative view of the popliteal sarcoma. D. Surgical resection site after tumor removal. The sciatic nerves and the popliteal vessels were preserved. E. The pedicles to the tumor are identified and ligated.

▪ Soft Tissue Reconstruction After the tumor is resected (TECH FIG 3A), the two heads of the gastrocnemius are sutured to each other and to the hamstring muscles to form a uniform muscle layer that covers the popliteal space (TECH FIG 3B). This wound closure technique minimizes the occurrence of deep wound infection by forming a muscular barrier between the skin incision and the popliteal space. The resected tumor specimen is shown in TECH FIG 3C,D. P.379

TECH FIG 3 • A. Intraoperative photo showing the entire popliteal fossa exposed and tumor and vessels removed. The peroneal, tibial, and popliteal nerves all remain intact. B. Closure of popliteal space. The medial and lateral heads of the gastrocnemius muscles are tenodesed below the sciatic nerve to cover the popliteal vessels. The medial (semimembranosus muscle) and the lateral hamstrings (biceps femoris muscle) are similarly tenodesed proximally to close the popliteal space and are also tenodesed to the gastrocnemius repair. This closure closes off all the dead space as well as protecting the popliteal vessels and provides a nice muscle base if a skin graft is needed. C. Gross specimen of the popliteal sarcoma. D. The tumor transected.

PEARLS AND PITFALLS Soft tissue sarcomas of the popliteal fossa commonly displace the usual anatomic landmarks. To locate the components of the neurovascular bundle, one must expose regions that are proximal and distal to the popliteal fossa, identify the major nerves and vessels, and follow them to the popliteal fossa. The sciatic nerve is proximally identified between the medial and lateral hamstrings; distally, the peroneal nerve is carefully identified posterior to the fibular head, immediately below the thin popliteal fascia, and the tibial nerve is found between the two heads of the gastrocnemius.

The popliteal vessels are identified proximal to the popliteal fossa as they exit the adductor hiatus and distally between the two heads of the gastrocnemius muscle. We routinely detach the origin of the medial and lateral hamstrings and both heads of the gastrocnemius muscle to achieve a wide exposure. In the popliteal space, the nerves are usually found posterior to the tumor mass and the vessels are usually anterior to it. P.380 While running through the popliteal fossa, the popliteal artery branches into two superior, a single middle, and two inferior genicular arteries. The inferior genicular vessels pull the popliteal artery toward the joint capsule and usually must be ligated to allow its mobilization. The popliteal vein, which runs more superficial to the artery, lies between the popliteal artery and the tibial nerve. The two main venous tracts responsible for the venous drainage of the leg are the popliteal vein and the greater saphenous vein. During tumor resection, excision of the popliteal vein may be unavoidable; for this reason, care should be taken not to damage the greater saphenous vein, which might be the only remaining venous tract. Moreover, if the popliteal artery and vein are resected, the contralateral greater saphenous vein should be harvested to reconstruct the popliteal artery. Ligation of both the popliteal vein and the ipsilateral greater saphenous vein may lead to severe venous insufficiency.

POSTOPERATIVE CARE AND REHABILITATION After surgery, the patient is placed in a long, posterior splint in 15 to 30 degrees of knee flexion to relieve tension from the neurovascular bundle and skin incision. Physiotherapy for muscle strengthening and range of motion is not started until the skin incision is completely healed.

OUTCOMES Only five case series of soft tissue sarcomas were identified in the English literature.3,6,8,9,11 All of the studies found that the prognosis was equivalent to that of soft tissue sarcomas in other locations and the limb salvage rate was high. In a recently published case series of 29 patients with popliteal sarcomas with a median postoperative follow-up of 79 months, of the 16 patients with high-grade tumors, 3 (19%) had local recurrences and 4 (25%) had distant metastases, of these, 2 died.9 None of the patients with low-grade tumors had local recurrences or distant metastases. The overall limb salvage rate was 86.2%; for the patients with highgrade tumors, it was 75%.9

COMPLICATIONS Superficial wound dehiscence is the most common complication. It usually occurs during adjuvant radiation therapy and sometimes necessitates local surgical débridement. Peroneal palsy is most commonly due to neurapraxia and usually resolves after several weeks. Knee range-of-motion limitation is usually secondary to adjuvant radiation therapy to the popliteal fossa. In our series of 29 patients with popliteal sarcomas, 14 of the 26 patients (53.8%) who underwent primary resections had full range of motion of the knee joint, 12 patients (46.1%) had mild to moderate limitations

in knee flexion (120 to 90 degrees), and 4 patients (15.3%) had mild flexion contractures (5 to 15 degrees).9 No patient in our series required knee manipulation or contracture release.

REFERENCES 1. Bickels J, Wittig JC, Kollender Y, et al. Sciatic nerve resection: is that truly an indication for amputation? Clin Orthop Relat Res 2002;399:201-204. 2. Brooks AD, Gold JS, Graham D, et al. Resection of the sciatic, peroneal, or tibial nerves: assessment of functional status. Ann Surg Oncol 2002;9:41-47. 3. Eilber FC, Eckardt JJ, Rosen G, et al. Large, deep, high-grade extremity sarcomas: treating tumors of the flexor fossa. Surg Oncol 1999;8:211-214. 4. Enneking WF, Spanier SS, Malawer MM. The effect of the anatomic setting on the results of surgical procedures for soft parts sarcoma of the thigh. Cancer 1981;47:1005-1022. 5. Fuchs B, Davis AM, Wunder JS, et al. Sciatic nerve resection in the thigh: a functional evaluation. Clin Orthop Relat Res 2001;382:34-41. 6. Huh WW, Guadagnolo BA, Munsell MF, et al. Soft tissue sarcomas of the popliteal fossa: a singleinstitution retrospective review. Cancer 2011;117(12):2728-2734. 7. Peabody TD, Simon MA. Principles of staging of soft-tissue sarcomas. Clin Orthop Relat Res 1993;289:19-31. 8. Philippe PG, Rao BN, Rogers DA, et al. Sarcoma of the flexor fossa in children: is amputation necessary? J Pediatr Surg 1992;27: 964-967. 9. Pritsch T, Bickels J, Winberg T, et al. Popliteal sarcomas: presentation, prognosis, and limb salvage. Clin Orthop Relat Res 2007;455:225-233. 10. Shiu MH, Collin C, Hilaris BS, et al. Limb preservation and tumor control in the treatment of popliteal and antecubital soft tissue sarcomas. Cancer 1986;57:1632-1639. 11. Yang RS, Lane JM, Eilber FR, et al. High-grade soft-tissue sarcoma of the flexor fossae. Cancer 1995;76:1398-1404.

Chapter 34 Soleus Resection Amir Sternheim Jacob Bickels Martin M. Malawer

BACKGROUND Malignant tumors of the soleus and gastrocnemius muscles are rare and have been traditionally treated with above-knee amputation. During the past 20 years, the treatment of soft tissue sarcoma of the lower extremities has undergone a dramatic shift toward limb salvage procedures. Better understanding of the biologic behavior of these tumors, the availability of effective neoadjuvant chemotherapy (which often decreases the tumor size and facilitates a more conservative resection), and the recognition that close negative surgical margins in conjunction with postoperative radiation therapy often provide good local control, thus allowing tumor resection instead of amputation in most cases.

ANATOMY The soleus and gastrocnemius muscles form a tripartite muscle sometimes referred to as the triceps surae muscle. Together with the plantaris muscle, they form the superficial posterior muscle group of the leg. These muscles act together in plantarflexing the foot and ankle joint. The gastrocnemius muscle is the most superficial in the superficial posterior compartment and forms most of the prominence of the calf. It has two heads of origin. Its medial head is slightly larger and extends a little more distal than its lateral head. The two heads converge at the inferior margins of the popliteal fossa where they form the inferolateral and inferomedial boundaries. The lateral head originates from the lateral surface of the lateral femoral condyle and the medial head arises from the popliteal surface of the femur, superior to the medial condyle. The soleus muscle is a broad, fleshy muscle that lies deep to the gastrocnemius muscle. It arises from the posterior aspect of the head and superior fourth of the fibula, the soleal line, and the middle third of the medial border of the tibia. It also arises from the tendinous arch between the tibia and fibula, which arches over the tibial vessels. The soleus muscle and both heads of the gastrocnemius converge to form the Achilles tendon, which inserts into the posterior surface of the calcaneus.

INDICATIONS Tumors that arise from and are completely within the soleus muscle Most low-grade and some high-grade sarcomas

IMAGING AND OTHER STAGING STUDIES Computed Tomography and Magnetic Resonance Imaging Careful examination of the computed tomography (CT) and magnetic resonance imaging (MRI) is essential in determining resectability. Tumors that extend to and around the popliteal trifurcation or into the gastrocnemius

muscles usually require an amputation (FIG 1). The popliteal space must also be evaluated. Proximal tumors arising within the soleus muscle often extend into the popliteal space and may involve the popliteal vessels, the sciatic nerve, or both.

Bone Scanning Bone scans may show involvement of the adjacent tibia, fibula, or both. Areas of uptake should lead to close examination of the corresponding cuts of the MRI and CT scans.

Angiography and Other Studies Biplane angiography is very useful in determining vascular displacement or encasement. Careful analysis of the popliteal trifurcation is necessary before surgery and may indicate tumor involvement and thus the need for an amputation.

Biopsy The biopsy site should be in line with the planned incision for resection and must be located over the most prominent portion of the tumor. Core needle biopsy has been shown to provide reliable pathologic diagnoses and is our preferred method. Multiple samples can be collected from the same puncture site. Areas where major arteries and veins traverse should be avoided so as not to penetrate the vessels and risk tumor cell contamination.

SURGICAL MANAGEMENT Care must be taken to identify, mobilize, and protect critical structures in the posterior leg.

Positioning Resection is performed with the patient in a prone position. General or epidural anesthesia is used. P.382

FIG 1 • This patient with an alveolar soft part sarcoma of the soleus muscle was treated with induction chemotherapy followed by limb salvage surgical resection and reconstruction with a Gore-Tex vascular graft. A,B. The axial and coronal T2-weighted MRIs show a large tumor arising within the soleus muscle. Arrows show the extension of the tumor. C. T2-weighted MRI demonstrating a tumor arising from the soleus and encroaching on both the posterior tibial artery and the peroneal artery. Both vessels appear patent at this point in time, although an angiogram may be useful for surgical planning. D. Three-dimensional (3-D) CT angiogram is useful to determine the local compartmental anatomy and the proximity of the soleus tumor to the peroneal vessels and the posterior tibial artery and will demonstrate any vascular anomalies within the planned surgical field.

TECHNIQUES ▪ Resection of Soleus Muscle with or without Adjacent Gastrocnemius Muscle The initial incision is made longitudinally on the posterior aspect of the leg and shifted medially or laterally, depending on the anatomic location of tumor (TECH FIG 1). A lateral incision is used if resection of the lateral gastrocnemius is planned. A midline posterior incision is used for resections of the medial gastrocnemius, soleus, and deep posterior compartment.

The fascia is dissected with the subcutaneous tissues, and large fasciocutaneous flaps are raised. The peroneal nerve is first identified and placed within a vessel loop; this is followed by careful dissection to identify the sciatic and tibial nerves. The popliteal vessels are identified by opening up the deep fascia overlying the two heads of the gastrocnemius. Radical excision of the medial or lateral heads of the gastrocnemius is achieved by ligation of their main pedicle (medial or lateral sural artery and vein, respectively) and transection of their femoral origin and insertion to the Achilles tendon. Exposure for resection of the soleus muscle is achieved by partial or complete Achilles tenotomy and reflection of the medial and lateral heads of the gastrocnemius muscle proximally. By blunt dissection, the soleus is separated from the transverse intermuscular septum, which outlines the deep posterior compartment. The soleus can then be detached from its tibial and fibular origins and calcaneal insertion. Residual defects in the Achilles tendon should be reconstructed. The wound is then closed over closed suction drains. P.383

TECH FIG 1 • A. Anatomy and a utilitarian approach to the posterior compartment of the leg. B. Clinical photograph demonstrating the planned surgical midline incision and location where the medial and lateral heads of the gastrocnemius will be released. C. Exposure of the tumor and identification of the posterior vessels requires the release of the medial and lateral heads of the gastrocnemius muscle from the Achilles tendon. D. Following incision and creation of fasciocutaneous flaps, the identification and mobilization of critical anatomic structures of the posterior leg occurs. E. The medial and lateral heads of the gastrocnemius have been mobilized. F. Once the medial gastrocnemius is elevated, the soleus muscle is visualized and tumor resection can occur. (continued) P.384

TECH FIG 1 • (continued) G. The massive defect created by wide resection of a soleus muscle sarcoma or carcinoma. H. Following tumor resection, a portion of the lateral soleus was retained in this case. The peroneal artery and vein, posterior tibial artery and vein, and the posterior tibial nerve all remain intact.

▪ Functional Reconstruction after Resection Functional reconstruction is usually necessary after resection of soleus tumors because of the complete resection of the proximal part of the Achilles tendon. It consists of tenodesing the medial and lateral heads of the gastrocnemius muscle and incorporating them with a Gore-Tex vascular graft. The length of the vascular graft depends on the size of the tumor and the gap between the resected stump and the Achilles tendon. The Gore-Tex vascular graft is sutured to the stump of the Achilles tendon with a 3-mm Dacron tape and no. 0 Ethibond sutures (TECH FIG 2A-D).

TECH FIG 2 • A. The Gore-Tex vascular graft was sutured to the stump of Achilles tendon. Inset shows a close-up of the graft stump junction. B. Suturing the medial and lateral heads of the gastrocnemius muscle and their incorporation with the Gore-Tex vascular graft. C. This intraoperative photograph shows the anatomic defect reconstructed with the Gore-Tex vascular graft (arrows), which was anastomosed to the remaining gastrocnemius muscle (MG, LG) and the stump of the Achilles tendon (AT) with no. 0

Ethibond and 3-mm Dacron tape. (continued)

TECH FIG 2 • (continued) D. Postoperative MRI shows the Gore-Tex graft extending from the insertion of gastrocnemius muscle to the remaining stump of the Achilles tendon. E. After tumor resection, the surgical specimen consists of the biopsy tract (BX), the tumor, and the entire soleus muscle belly (arrow). The retracted gastrocnemius and soleus muscle stump is pulled out and sewn with the Gore-Tex aortic graft under moderate tension with a 3-mm Dacron tape and no. 0 Ethibond sutures. After resection of the tumor, the surgical specimen consists of the biopsy tract, the tumor, and the entire soleus muscle belly (TECH FIG 2E). The foot is kept in the neutral position during these reconstructive procedures. A posterior splint is used to maintain the foot in neutral position and the knee in 15 degrees of flexion.

P.385

PEARLS AND PITFALLS Preoperative

▪ Large tumors of the soleus muscle may extend further than anticipated. ▪ Preoperative evaluation of the popliteal space and vessels is mandatory.

Intraoperative

▪ Reconstruction with a Gore-Tex graft after resection is recommended for large soleus defects. ▪ The surgeon should carefully mobilize the popliteal vessels before attempting to resect the tumor. An intraoperative Doppler scan may be useful.

POSTOPERATIVE CARE AND REHABILITATION Postoperatively, the leg is immobilized in a long-leg splint followed by a short-leg walking cast for a total of 3 to

4 weeks, depending on the extent of the soft tissue resection.

FIG 2 • Clinical photographs taken 3 years after the surgery. A,B. This patient has no significant difference in dorsiflexion and plantarflexion of the ankle compared with the contralateral leg. C. This patient was able to raise her heel from the floor without pain. Patients who underwent reconstruction of the Achilles tendon with Gore-Tex graft should be immobilized in an ankle—foot orthosis for an additional 8 weeks. Rehabilitation includes leg strengthening, balance, and gait training (FIG 2). P.386

OUTCOMES There have been only a few reported cases of soleus muscle resections for sarcomas. Reconstruction with a Gore-Tex graft allows the patient an almost normal gait (heel-toe, push off) and an almost normal range of motion of the ankle. Local recurrence may require an amputation.

COMPLICATIONS The most common complications are flap necrosis and tumor recurrence. Vascular occlusion of the posterior tibial artery is rare. Radiation therapy should be deferred a few weeks to permit the Gore-Tex graft to heal.

Chapter 35 Surgical Management of Metastatic Bone Disease: Femoral Lesions Jacob Bickels Martin M. Malawer

BACKGROUND The femur is the most common site for metastatic bone disease requiring surgery. Because it is a major weight-bearing bone with minimal space for surgical errors, the operative procedure must be carefully planned and meticulously executed, with the aim of achieving durable reconstruction. Detailed preoperative clinical and imaging evaluation is essential to define the morphologic characteristics of the lesion that validate surgical intervention and to distinguish between lesions that can be managed with curettage and cemented fixation and those that require resection with endoprosthetic reconstruction.1,6,7 Unlike primary sarcomas of the femur, metastatic tumors usually have a small soft tissue component, even in the presence of extensive bone destruction. This feature allows the sparing of extracortical structures, such as the joint capsule, overlying muscles, and muscle attachments, and the possibility of applying them for reconstruction and preservation of function. Because of distinctive differences in anatomic and surgical considerations, surgeries around the proximal femur, femoral diaphysis, and distal femur will be discussed separately (FIG 1).

ANATOMY Proximal Femur A thick joint capsule encircles the femoral head and neck and attaches to the base of the neck. Key elements at the lateral aspect: The greater trochanter is the insertion site for the gluteus medius muscle (lateral stabilizer and hip abductor) and the origin for the vastus lateralis muscle. Key elements at the medial aspect: The minor trochanter is the insertion site for the psoas muscle (medial stabilizer and hip flexor).

Femoral Diaphysis The femoral diaphysis is encircled by two muscle layers: First layer: the vastus intermedius muscle Second layer: The rectus femoris and vastus medialis muscles intersect at the anteromedial aspect, and the rectus femoris and the vastus lateralis muscles intersect at the anterolateral aspect.

Distal Femur The medial femoral condyle is positioned below the insertion site of the vastus medialis muscle. The lateral femoral condyle is positioned below the insertion site of the vastus lateralis muscle.

INDICATIONS

Pathologic fracture Impending pathologic fracture Intractable pain associated with locally progressive disease that has shown inadequate response to narcotics and radiation therapy Solitary bone metastasis in selected patients and tumor types (eg, those with breast cancer and renal cell carcinoma)

FIG 1 • Metastatic tumors at the proximal femur, femoral diaphysis, and distal femur.

IMAGING AND OTHER STAGING STUDIES Plain radiographs of the entire femur are mandatory to rule out coexisting metastases that may influence the extent and technique of surgery. Computed tomography P.388 of the lesion will clearly define the extents of soft tissue component and bone destruction. Total body bone

scintigraphy is done to detect coexisting metastases elsewhere in the skeleton (FIG 2). The results of imaging should provide the surgeon with answers to the following questions: Is the lesion an impending fracture? (If not, it should probably be treated nonoperatively.)

FIG 2 • A. Plain radiograph showing a metastatic lesion of the proximal femur. The surrounding cortices are intact. Surgery consisted of curettage and reconstruction with a cemented intramedullary nail. B. Metastatic lesion at the same site with extensive circumferential bone destruction. Surgery in this case entailed resection of the proximal femur and reconstruction with an endoprosthesis. Anteroposterior (AP) plain radiograph (C) and computed tomography (D) of the distal femur showing a metastatic lesion at the left medial femoral condyle. The lateral condyle and articular cartilage are preserved and form an anatomic continuum, which allows the fixation of a cemented reconstructive device. AP (E) and lateral (F) plain radiographs and computed tomography (G) of the distal femur showing a large metastasis with destruction of the entire anterior aspect of the bone and considerable thinning of the posterior cortex. Surgery included resection of the distal femur and reconstruction with an endoprosthesis. Are there additional femoral metastases? If so, can they be managed by nonoperative techniques or do they also require surgery? What is the appropriate surgical approach? As a rule, tumor curettage with cemented fixation is indicated for lesions in which the remaining cortices allow containment of the fixation device. Otherwise, surgery consists

of resection of the affected bone segment with prosthetic reconstruction. P.389

TECHNIQUES ▪ Proximal Femur Position and Incision The patient is placed supine on the operating table, with the buttock of the affected side close to its edge. The operating table is positioned in a 30-degree tilt away from the surgeon. A straight longitudinal incision is made along the tip of the greater trochanter and femoral diaphysis (TECH FIG 1). It should begin 5 cm proximal to the greater trochanter to allow the introduction of a femoral nail and 5 cm below the lower edge of the lesion to enable adequate tumor curettage. Exposure The fascia lata is divided longitudinally and retracted to expose the lower edge of the gluteus medius muscle and its insertion site at the greater trochanter muscle, the vastus ridge, and the upper part of the vastus lateralis muscle (TECH FIG 2A,B). Using electrocautery, the vastus lateralis muscle is detached from the vastus ridge and the lower aspect of the proximal diaphysis and reflected anteriorly to expose the diaphyseal cortex (TECH FIG 2C-E). A longitudinal cortical window with oval edges is made below the vastus ridge (TECH FIG 2F). Tumor Removal Gross tumor is removed with hand curettes (TECH FIG 3A,B). Curettage should be meticulous and should leave only microscopic disease in the tumor cavity. It is followed by high-speed burr drilling of walls of the tumor cavity (TECH FIG 3C,D).

TECH FIG 1 • A straight longitudinal incision is made along the tip of the greater trochanter and femoral diaphysis. When a proximal femur resection is done, the gluteus medius muscle is detached and reflected from its insertion site at the greater trochanter muscle (TECH FIG 3E), the joint capsule is opened and the femoral head is dislocated from the acetabulum, the medial aspect of the proximal femur is freed of muscle attachments, and then an osteotomy is performed below the lower aspect of the tumor (TECH FIG 3F-H).

TECH FIG 2 • A,B. The fascia lata is divided longitudinally and retracted to expose the lower edge of the gluteus medius muscle and its insertion site at the greater trochanter muscle, the vastus ridge, and the upper part of the vastus lateralis muscle. C-E. The vastus lateralis muscle is detached from the vastus ridge and femoral diaphysis. (continued) P.390

TECH FIG 2 • (continued) F. A cortical window is made below the vastus ridge.

TECH FIG 3 • A,B. Gross tumor is removed with hand curettes. C,D. Curettage is followed by high-speed burr drilling of the walls of the tumor cavity. (continued) P.391

TECH FIG 3 • (continued) E. The gluteus medius muscle is detached and reflected from its insertion site at the greater trochanter muscle. F,G. The joint capsule is opened, the femoral head is dislocated from the acetabulum, its medial aspect is freed from muscle attachments, and an osteotomy is done below the level of the metastasis. H. Surgical specimen of an intra-articularly resected proximal femur. P.392 Mechanical Reconstruction Reconstruction begins with the introduction of an intramedullary nail. After proper positioning and length are verified, the nail is partially withdrawn and the entire tumor cavity is filled with cement (TECH FIG 4A). The nail is then pushed back into the medullary canal and fixed with interlocking screws (TECH FIG 4B,C). Alternatively, a side plate and a sliding screw can be similarly used for reconstruction. After resection of the proximal femur, a cemented tumor prosthesis is used to reconstruct the bone defect (TECH FIG 4D). Soft Tissue Reconstruction and Wound Closure The origin of the vastus lateralis muscle is reattached to the vastus ridge (TECH FIG 5A).

TECH FIG 4 • A. After the positioning of an intramedullary nail is verified, it is partially withdrawn and the tumor cavity is entirely filled with bone cement. B,C. After the cavity has been filled with cement, the nail is pushed back into the medullary canal and fixed with interlocking screws. D. A cemented prosthesis is used for reconstruction after resection of the proximal femur. If endoprosthetic reconstruction had been carried out, the remaining hip capsule is sutured tightly with a 3-mm Dacron tape around the neck of the prosthesis, forming a noose that provides immediate stability. The capsule is reinforced by rotating the external rotator muscles proximally and suturing them to its posterolateral aspect. The remaining abductor tendon is attached to the lateral aspect of the prosthesis through a metal loop, and the psoas muscle is attached to the medial aspect of the prosthesis at the level where the lesser trochanter had been (TECH FIG 5B). It is important to attach these two muscles to the prosthesis so that balanced function will be achieved. The surgical wound is then closed over suction drains and the patient is placed in balanced suspension or in tibial pin traction with the hip elevated and flexed 20 degrees. An abduction pillow can also achieve the correct positioning. P.393

TECH FIG 5 • A. The origin of the vastus lateralis muscle is reattached to the vastus ridge. B. The remaining joint capsule is sutured around the prosthetic head to its neck. The gluteus medius and psoas muscles are reattached to the lateral and medial aspects of the prosthesis, respectively.

▪ Femoral Diaphysis Position and Incision The patient is placed supine on the operating table, with the buttock of the affected side close to its edge. The operating table is positioned in a 30-degree tilt away from the surgeon.

TECH FIG 6 • A,B. Anteroposterior and lateral plain radiographs showing an impending fracture of the femoral diaphysis due to metastatic lesion. C. A longitudinal anteromedial incision is made at the level of the rectus femoris-vastus medialis junction. A diaphyseal lesion with a lateral cortical breakthrough is approached using a longitudinal incision along the anterolateral aspect of the thigh at the level of the interface between the rectus femoris and vastus

lateralis muscles, with the lesion located at the center of the incision (TECH FIG 6). P.394 A lesion with medial cortical destruction is similarly approached using an anteromedial incision at the level of the interface of the rectus femoris and vastus medialis. Exposure The interval between the rectus femoris and vastus lateralis muscles is opened, and the muscles are retracted to expose the vastus intermedius overlying the femoral diaphysis. The vastus intermedius is split longitudinally to expose the femoral diaphysis, and retractors are placed behind it (TECH FIG 7). This approach allows wide exposure of the affected bone with minimal injury to the overlying muscles. A longitudinal cortical window with oval edges is made above the lesion. Tumor Removal Gross tumor is removed with hand curettes (TECH FIG 8A,B). Curettage should be meticulous and should leave only microscopic disease in the tumor cavity.

TECH FIG 7 • The tumor is approached using the interval between the rectus femoris and vastus medialis muscles. The vastus intermedius is split to expose the underlying cortex, and an oval cortical window is made.

TECH FIG 8 • A,B. Gross tumor is removed with hand curettes. (continued)

TECH FIG 8 • (continued) C,D. Curettage is followed by high-speed burr drilling of the walls of the tumor cavity. This is followed by high-speed burr drilling of the walls of the tumor cavity (TECH FIG 8C,D). Mechanical Reconstruction Reconstruction begins with the introduction of an intramedullary nail either antegrade or retrograde, depending on the location of the lesion along the diaphysis. After proper positioning and length have been verified, the nail is partially withdrawn and the entire tumor cavity is filled with cement (TECH FIG 9). The nail is then pushed back into the medullary canal and fixed with interlocking screws. Soft Tissue Reconstruction and Wound Closure A suction drain is positioned along the femoral diaphysis muscle, and the vastus lateralis muscle is sutured to the rectus femoris muscle. P.395

TECH FIG 9 • An intramedullary nail is introduced and adequate positioning is verified. The nail is then partially withdrawn, the tumor cavity is entirely filled with cement, and the nail is reintroduced through the cement and secured with interlocking screws.

▪ Distal Femur Position and Incision The patient is placed supine on the operating table, with the affected knee flexed 30 degrees. A medial condyle lesion is approached using a longitudinal incision along the anteromedial aspect of the distal thigh at the level of the interface between the rectus femoris and vastus medialis muscles and 1 cm away from the medial border of the patella (TECH FIG 10).

TECH FIG 10 • A medial condyle lesion is approached using a longitudinal incision along the anteromedial aspect of the distal thigh at the level of the interface between the rectus femoris and vastus medialis muscles and 1 cm away from the medial border of the patella. A lesion of the lateral condyle is similarly approached using an anterolateral incision at the level of the interface of the rectus femoris and the vastus lateralis and lateral to the patella. P.396 Exposure The interval between the distal aspect of the vastus medialis and rectus femoris muscles is opened and the insertion of the vastus medialis to the quadriceps tendon, patella, and joint capsule is detached (TECH FIG 11A,B). The vastus medialis muscle is retracted posteriorly, exposing the underlying vastus intermedius muscle and the distal femur (TECH FIG 11C,D). A lesion at the lateral femoral condyle is approached using similar detachment and posterior reflection of the vastus lateralis muscle. This approach allows wide exposure of the affected bone with minimal injury to the overlying muscles. A longitudinal cortical window with oval edges is made above the lesion. Tumor Removal Curettage: Gross tumor is removed with hand curettes (TECH FIG 12A,B). Curettage should be meticulous and should leave only microscopic disease in the tumor cavity. It is followed by high-speed burr drilling of walls of the tumor cavity (TECH FIG 12C,D). When distal femoral resection is performed, the medial gastrocnemius muscle is detached from its origin in the distal femur to expose the popliteal fossa. An interval between the popliteal vessels and the posterior femur is then formed by ligation and transection of the geniculate vessels (TECH FIG 12E,F). The joint capsule is opened along its anteromedial border and the ligaments and menisci are removed (TECH FIG 12G).

TECH FIG 11 • A,B. The vastus medialis muscle is detached from its attachment to the rectus femoris muscle and inserted into the quadriceps tendon, patella, and joint capsule. C,D. The vastus medialis muscle is retracted posteriorly, exposing the vastus intermedius muscle and distal femur. A distal femur osteotomy is carried out at the appropriate location as determined by the preoperative imaging studies: 1 to 2 cm beyond the point of proximal tumor extension is generally appropriate for metastatic tumors (TECH FIG 12H-J). A tibial osteotomy is then done to allow the introduction of the prosthetic tibial component. The osteotomy is perpendicular to the long axis of the tibia and is done in the same manner as a standard knee arthroplasty, with approximately 1 cm of bone being removed. Mechanical Reconstruction A combination of a cemented intramedullary nail and a condylar plate achieves optimal stability and is preferred for reconstruction (TECH FIG 13A-C). After resection of the distal femur, a cemented tumor prosthesis is used for reconstruction (TECH FIG 13D-F). Soft Tissue Reconstruction and Wound Closure Suction drains are positioned along the femoral diaphysis, and the vastus medialis muscle is sutured to the rectus femoris muscle and its insertion sites along the quadriceps and patella. The medial gastrocnemius muscle is pulled up and sutured to the vastus medialis muscle (TECH FIG 14). P.397

TECH FIG 12 • A,B. Gross tumor is removed with hand curettes. C,D. Curettage is followed by high-speed burr drilling of the walls of the tumor cavity. E,F. The medial gastrocnemius muscle is detached and reflected, exposing the popliteal fossa. The posterior femur is isolated by ligation and transection of the geniculate vessels. G. The joint capsule is opened and released circumferentially from the femur. (continued) P.398

TECH FIG 12 • (continued) H,I. A distal femur osteotomy is done 1 to 2 cm beyond the point of proximal tumor extension. J. The surgical specimen.

TECH FIG 13 • A-C. A cemented intramedullary nail and a condylar plate are used to reconstruct metaphyseal lesions in which the remaining cortices allow containment of the fixation devices. (continued) P.399

TECH FIG 13 • (continued) D-F. A cemented tumor prosthesis is used for reconstruction after resection of the distal femur.

TECH FIG 14 • The vastus medialis muscle is sutured to the rectus femoris muscle and its insertion sites along the quadriceps and patella. The medial gastrocnemius muscle is pulled up and sutured to the vastus

medialis muscle.

P.400

PEARLS AND PITFALLS Proximal femur

▪ Adequate imaging of the entire femur allows the surgeon to decide whether to perform tumor curettage or resection with endoprosthetic reconstruction. ▪ Wide exposure of the tumor cavity, using an adequately positioned and large cortical window ▪ Meticulous curettage and burr drilling ▪ Reconstruction with hardware and cementation of the entire volume of the cavity ▪ Proximal femur resection: reconstruction with cemented implant, suturing of the joint capsule, and reattachment of the gluteus medius and psoas muscles ▪ Early ambulation and range-of-motion exercises; weight bearing as tolerated

Femoral diaphysis

▪ Exposure through the interval between the rectus femoris and vastus lateralis or medialis ▪ Wide exposure of the tumor cavity using an adequately positioned large cortical window ▪ Meticulous curettage and burr drilling ▪ Reconstruction with hardware and cementation of the entire volume of the cavity ▪ Early ambulation and range-of-motion exercises; weight bearing as tolerated

Distal femur

▪ Exposure through the interval between the vastus medialis and lateralis and the rectus femoris ▪ Wide exposure of the tumor cavity using an adequately positioned large cortical window ▪ Meticulous curettage and burr drilling ▪ Reconstruction with a cemented intramedullary nail and a condylar plate ▪ When distal femur resection is indicated, the gastrocnemius origin is detached to expose the popliteal fossa. ▪ Reconstruction is done with a cemented tumor prosthesis. ▪ Early ambulation and weight bearing as tolerated

POSTOPERATIVE CARE Proximal Femur Continuous suction is required for 3 to 5 days, and perioperative intravenous antibiotics are continued until the drainage tubes are removed. If tumor curettage had been done, rehabilitation should include early ambulation with unrestricted weight bearing as well as passive and active range of motion of the hip joint. After wound healing, usually 3 to 4 weeks after surgery, the patient is referred for adjuvant radiation therapy. Adjuvant radiation therapy is usually not required in patients who underwent proximal femur resection with endoprosthetic reconstruction. If endoprosthetic reconstruction had been done, the extremity is kept in balanced suspension for at least 5 days. Postoperative mobilization with total hip replacement precautions with or without an abduction brace and weight bearing as tolerated are continued for 6 weeks.

Femoral Diaphysis Continuous suction is required for 3 to 5 days, and perioperative intravenous antibiotics are continued until the drainage tubes are removed. Rehabilitation should include early ambulation with unrestricted weight bearing as well as passive and active range of motion of the knee joint. When wound healing is complete, usually 3 to 4 weeks after surgery, the patient is referred for adjuvant radiation therapy.

Distal Femur Continuous suction is required for 3 to 5 days, and perioperative intravenous antibiotics are continued until the drainage tubes are removed. If tumor curettage had been done, rehabilitation should include early ambulation with unrestricted weight bearing as well as passive and active range of motion of the knee joint. When the wound is healed, usually 3 to 4 weeks after surgery, the patient is referred for adjuvant radiation therapy. In the case of distal femur resection, the lower extremity is elevated for 3 days, until the first postoperative wound check, to prevent wound edema. Knee motion is restricted in an immobilizing brace for 2 to 3 weeks to allow healing of the surgical flaps and until the extensor mechanism is again functional. During that time, isometric exercises are carried out and weight bearing is allowed. Adjuvant radiation therapy is usually not required in patients who underwent distal femur resection with endoprosthetic reconstruction.

OUTCOMES AND COMPLICATIONS Functional outcomes and common complications of prosthetic replacements for metastatic bone disease are no different from those with the same operations for primary sarcomas of bone (see Chaps. 25 and 26).2,3,4,5,8 Because of the short life expectancy of most patients with metastatic bone disease, the problems seen at long-term follow-up such as aseptic loosening, the wearing down of polyethylene components, and fatigue prosthetic fractures are rarely seen. The real concerns in the setting of metastatic bone disease are local tumor recurrence and failure of reconstruction. Meticulous tumor removal, proper selection and use of fixation devices, and adjuvant radiation therapy have made these complications rare: Local recurrence and reconstruction failures are seen in less than 5% of the patients.

REFERENCES 1. Aaron AD. Treatment of metastatic adenocarcinoma of the pelvis and the extremities. J Bone Joint Surg Am 1997;79A:917-932. 2. Bickels J, Meller I, Henshaw RM, et al. Reconstruction of hip joint stability after proximal and total femur resections. Clin Orthop Relat Res 2000;375:218-230. P.401 3. Bickels J, Wittig JC, Kollender Y, et al. Distal femur resection with endoprosthetic reconstruction: a longterm followup study. Clin Orthop Relat Res 2002;400:225-235. 4. Capanna R, Morris HG, Campanacci D, et al. Modular uncemented prosthetic reconstruction after resection of tumours of the distal femur. J Bone Joint Surg Br 1994;76B:178-186. 5. Dobbs HS, Scales JT, Wilson JN, et al. Endoprosthetic replacement of the proximal femur and acetabulum. J Bone Joint Surg Br 1981;63B:219-224. 6. Harrington KD. Impending pathologic fractures from metastatic malignancy: evaluation and management. AAOS Instr Course Lect 1986;35:357-381. 7. Harrington KD, Sim FH, Enis JE, et al. Methylmethacrylate as an adjunct in internal fixation of pathological

fractures. J Bone Joint Surg Am 1976;58A:1047-1055. 8. Kawai A, Muschler GF, Lane JM, et al. Prosthetic knee replacement after resection of a malignant tumor of the distal part of the femur: medium to long-term results. J Bone Joint Surg Am 1998;80A:636-647.

Chapter 36 Foot and Ankle Amputations: Ray Resections and Lisfranc/Chopart Braden J. Criswell Yvette Ho Martin M. Malawer Loretta B. Chou

BACKGROUND Malignant tumors of the foot present a significant and formidable challenge to the orthopaedic oncologist due to the foot's unique function and anatomic peculiarities. Both bone and soft tissue contribute to the structure and function of the foot. Furthermore, the foot is composed of compact compartments that are interconnected by nerves and vascular structures. Complete resection (wide local excision) of osseous structures of the foot is difficult because of the interruption of these complex anatomic relationships, which afford stability to the foot, in addition to the interconnected compartments. Malignant tumors of bone are rare in the foot and rarer still in locations distal to the metatarsophalangeal joints.5,9,12,14,17,18 Many of these tumors are treated with amputations. FIG 1A shows all anatomic sites, FIG 1B shows the distribution of malignant and benign cases, and FIG 1C shows the distribution of all types of surgical procedures. In the senior author's experience of foot and ankle tumors in 153 cases, 31 amputations were performed (see FIG 1C). Fortunately, tumors distal to the metatarsophalangeal joint can be treated by amputation through the metatarsophalangeal joint with minimal disruption to function. The only exception is the first ray, which typically bears 50% of the weight with toe-off during each gait cycle. Therefore, preservation of as much proximal phalanx as possible is important to optimize this important structure.

ANATOMY The foot is uniquely adapted for bipedal motion and as such is essentially a tripod. The tripod is basically formed by the first ray, the fifth ray, and the calcaneus and is supported by the osseous configuration of bones in the midfoot that form a Roman arch, which in and of itself is inherently stable. These bones are supported by ligamentous structures as well as tendons that help preserve the arch and support foot function. For this reason, resections of the first and fifth rays typically result in significant alterations in function, especially the first ray. The resulting forces after resection of the first ray result in transfer to the lesser metatarsals, which are ill adapted to structurally support the weight of the body, resulting in transfer metatarsalgia. These structural alterations can be mitigated in part by the judicious use of orthotics, such as a medial heel wedge to transfer the forces farther lateral or the use of a metatarsal bar, which will more evenly distribute the weight across the lesser metatarsals. Resection of the fifth ray is relatively easily compensated for by creating an orthosis that transfers the forces medially; thus, a lateral heel wedge is beneficial. Resection of the middle rays results in insignificant loss of function and acceptable cosmesis. The only net result is narrowing of the forefoot, which can be easily compensated for with shoe modifications. The Lisfranc joint is the tarsometatarsal joint. An amputation at this level will preserve the dorsiflexors and

plantarflexors. These amputation levels are highly functional with minor shoe-wear modifications and forefoot fillers. If the metatarsal bases can be preserved using a transmetatarsal amputation, the functional outcome is improved. The Chopart joint is also known as the transverse tarsal joint. It includes the talonavicular and calcaneocuboid joints. An amputation at this level preserves the plantarflexors but sacrifices the dorsiflexors, often resulting in an equinus contracture due to unopposed action of the Achilles tendon. To circumvent this problem, the tibialis anterior is used. It is detached from the tarsal navicular with a cuff of soft tissue, preferably periosteum. A drill hole is made through the neck and head of the talus in an oblique fashion from dorsolateral to plantar medial. The tendon is then routed through this bone tunnel and sewn to itself or soft tissue as it exits through the tunnel. This repair may be augmented with bone anchors placed near the dorsal opening of the tunnel. The residual foot is maintained in maximal dorsiflexion (FIG 2). The advantage of a Chopart amputation over a Syme amputation is the maintenance of hindfoot height. This is an end-bearing residual limb and the patient can negotiate short distances without modified shoe wear or prosthetic fitting.

INDICATIONS Tumors involving the toe or metatarsal bone are rare. Primary tumors affecting the foot, including osteosarcomas, have a low incidence.2,4,14 Metastatic tumors of the foot are also rare.9,20 The most common sites of primary tumors which metastasize to the foot are lung, kidney, and colon.9

Ray Resections The indications for ray resections are tumors involving the toe or metatarsal bone. Benign tumors make up the majority of these lesions.12 P.403

FIG 1 • A. All anatomic sites of tumors of the foot and ankle (n = 153). B. Distribution of malignant and benign tumors of the foot and ankle (n = 153). C. Distribution of surgical procedures for tumors of the foot and ankle (n = 153).

Lisfranc Extensive tumor involving the first and second interspaces in adjacent metatarsals or multiple metatarsals (FIG 3)

Chopart Tumors extending to the tarsometatarsal joint with soft tissue extension. FIG 4 shows the pathology specimen after wide resection of a chondrosarcoma involving multiple small bones of the foot.

FIG 2 • Good dorsiflexion function after Chopart amputation.

PATIENT HISTORY AND PHYSICAL FINDINGS Patients with tumors of the metatarsals complain of pain with an associated mass. The mass may be small and chronic. It may be first noticed after a minor injury. The patient may have difficulty with weight-bearing activities, including walking and standing. Shoe wear, particularly fashionable shoes, may be limited. Physical examination (Table 1) often shows a tender mass localized to the toe, metatarsal, or midfoot. There may be associated swelling. If a sensory nerve overlies the mass, there may be paresthesias. If the mass is large, there may be loss of motion or discomfort with active range of motion of the foot and ankle.

IMAGING AND OTHER STAGING STUDIES Preoperative studies include standing plain radiographs of the foot, including anteroposterior, lateral, and oblique views. If there is involvement of the ankle joint, anteroposterior and mortise views of the ipsilateral ankle are obtained as well. Magnetic resonance imaging (MRI) is important to evaluate the amount of involvement of the metatarsals to determine the level of amputation (FIG 5). It also shows the extent P.404 of soft tissue tumors and may be helpful in distinguishing benign from malignant tumors.19

FIG 3 • Synovial sarcoma involving the forefoot. A. This patient's radiographs showed radiodensity surrounding the second metatarsal, a typical radiographic appearance of a synovial sarcoma. B,C. MRIs show extensive soft tissue mass. The patient was treated with a Chopart amputation.

SURGICAL MANAGEMENT The goal of the surgical procedure is to remove the tumor with adequate margins. FIG 6 illustrates a case of osteosarcoma of the calcaneus. Osteosarcoma is usually treated with wide resection, but in this case, the tumor was confined to the calcaneus. The patient had a good response to adjuvant chemotherapy, with 100% tumor necrosis and was treated with the only calcaneal prosthesis reported in the world. A long plantar flap is important for a sturdy end-bearing stump. The quality of the tissue is more important than the quantity.1 The bony edges should be smooth and beveled if possible. Myodesis is helpful to pad the end of the stump. Reconstruction of the anterior tibialis tendon insertion into the neck of the talus in the Chopart amputation will help prevent an equinus contracture.

FIG 4 • Chondrosarcoma can spread to involve multiple sites. This photograph shows the pathology specimen after a below-knee amputation of a chondrosarcoma involving multiple small bones of the foot.

Preoperative Planning Preoperative planning is crucial for a good outcome. The preoperative radiographs, computed tomography (CT), and MRI studies are important to determine the amount of tumor involvement (FIG 7). They also show the extent of soft tissue tumors and may be helpful in distinguishing benign from malignant tumors.19 The results of the biopsy will determine the level of amputation. The level of amputation is an important part of preoperative planning. The length of the residual stump is as important as the quality of soft tissue. There must be adequate padding of skin, subcutaneous fat, muscle, and tendons to cover the end of the bones.

Table 1 Physical Examination Methods Examination

Technique

Significance

Inspection

Evaluate the lower extremity with the patient undressed from the knees.

Examination of both extremities allows for comparison to identify abnormalities.

Palpation

Gentle and deep palpation of the mass or area of pain

Evaluates tenderness of the mass; evaluates whether the mass is mobile or fixed

Range of motion

Observe passive and active range of motion of the foot and ankle.

Identifies joint involvement with tumor

Vascular examination

Palpate dorsalis pedis and posterior tibia arteries.

Evaluates vascularity of the extremity and whether there is tumor involvement

Neurologic examination

Evaluate motor strength and sensation to light touch.

Evaluates involvement of muscles and sensory nerves

P.405

FIG 5 • Chondrosarcoma of the calcaneus. A,B. MRI shows extension into the soft tissue. It was treated with cryosurgery but recurred and a below-knee amputation was performed. C,D. Unicameral bone cyst (UBC) of the calcaneus. The radiograph shows the typical expansile appearance of the UBC. The CT scan shows greater bony detail. The lesion was treated with curettage, graft, and PMMA.

FIG 6 • Osteosarcoma is an aggressive malignant tumor that has been reported to occur in the calcaneus. Osteosarcoma is usually treated with wide resection, but in this case, the tumor was confined to the calcaneus. The patient had a good response to adjuvant chemotherapy, with 100% tumor necrosis, and was treated with the only calcaneal prosthesis reported in the world. A. The lateral radiograph shows the expansile tumor. B. The bone scan shows isolated involvement. C,D. At 10 years postoperatively, the patient was tumor-free and enjoyed working and normal activities. P.406

FIG 7 • A. Benign tumors can show cortical thickening, mimicking a stress fracture. In this case, it was a benign lesion of the second metatarsal. B. Clinical photograph shows increased space between the metatarsals from the mass. C. MRI shows the amount of soft tissue involvement. D,E. Pigmented villonodular synovitis (PVNS) is usually treated with simple excision. This case localized to the plantar aspect of the first metatarsal head. Clinical photographs show the mass. F. MRI shows soft tissue involvement. G. Intraoperative photograph shows tumor resection.

Positioning The patient is placed supine on the operating table. A thigh tourniquet is placed over adequate padding, such as Webril. A bump may be placed proximal to the sciatic notch on the ipsilateral hip to limit external rotation of the extremity during the procedure.

Approach The surgical approach is planned preoperatively. It is important to maintain as much plantar skin as possible because this skin is thicker and has specialized columns of plantar fat for weight bearing. Ray resections are performed through a longitudinal dorsal incision in line with the involved metatarsal.

Lisfranc and transmetatarsal amputations are performed through a midfoot incision, with a long plantar flap. This is the same approach with the Chopart amputation. The plantar skin is thicker and has specialized columns of plantar fat to provide for a weight-bearing stump. P.407

TECHNIQUES ▪ Ray Resection In performing a ray resection, an incision is made longitudinally and dorsally in line with the involved metatarsal. At the metatarsophalangeal joint, the incision is carried plantarly in a curvilinear fashion around the joint (TECH FIG 1). This tissue is then used to reconstruct the resulting web space between the adjacent digits. The sensory nerves are identified just beneath the skin and are pulled distally and transected sharply with a scalpel. The extensor tendon is also transected sharply at and proximally near the tarsometatarsal joint. The common digital nerve is identified along with the vascular bundle. If they are involved or closely adherent to the tumor pseudocapsule, they are ligated proximally. The lumbrical and interosseous muscles are transected proximally, exposing the base of the metatarsal. It is preferable to preserve the base of the metatarsal if possible because this does not cause any disruption in the arch formed by the tarsal-metatarsal articulation. An oscillating saw is used to transect the metatarsal, or the metatarsal is disarticulated at the tarsometatarsal joint and elevated. The resection then is performed from proximal to distal. The flexor tendon is identified and transected. The entire metatarsal is then excised along with the adjacent soft tissue (lumbricals, intrinsics, and flexor extensor tendons). The dissection is then carried distally and plantarward. The capsular structures of the metatarsophalangeal joint are then separated from the underlying dermis and the ray is removed. A suture is placed through the capsular structures of the adjacent metatarsal heads. Pressure is then applied to the tibial and fibular aspect of the foot to close the defect between the adjacent metatarsals, and a 0 nonabsorbable suture is used to anchor the capsular structures between the adjacent metatarsals to bring the metatarsals together and narrow the defect between the adjacent rays. A small drain is placed in the defect and brought out through a separate puncture wound distally. The subcutaneous tissue is then closed with 3-0 absorbable sutures placed in interrupted fashion. The skin is closed with 4-0 nylon sutures placed in interrupted fashion.

TECH FIG 1 • A. Skin incision location in a metatarsal ray resection. B. Dorsal incision. C. Plantar incision. D. The plantar flap is longer and is brought dorsally to cover the bony end of the stump. A bulky dressing is applied, maintaining even compression across the foot and compressing the adjacent metatarsals to decrease tension on the capsular stitch maintaining the metatarsal heads in close proximity. If the flexor or extensor tendons are not involved with tumor, they can be woven through the metatarsal heads to create a sling to anchor the metatarsal heads in close proximity and maintain the close space between the metatarsal heads. First Ray Resection with Reconstruction with Autogenous Fibular Graft Under epidural anesthesia, an incision is made over the first metatarsal. Anterior and posterior fasciocutaneous flaps are made extending to the level of the second metatarsal anterior and posterior. The proximal limb of the incision extends beyond the metatarsal cuneiform joint and the distal incision extends to the web space. Resection consists of the planes between the first and second metatarsals following the bone in the second metatarsal through the metatarsal cuneiform joint and posteriorly and around the first metatarsal the flexor longus muscle tendon. The distal metatarsal is osteotomized at the condyles and proximally just distal to the joint. The tumor mass is removed; the anterior tibial tendon, peroneal tendons, and anterior tibial vessels are preserved. Reconstruction is performed with a fibular graft from the midshaft of the fibula of the ipsilateral limb. This is placed within the defect, measuring about 8 cm between the cuneiform and the metatarsal head. Fixation is achieved with two small cortical interfragmentary screws proximally and distally. The hallux is maintained in neutral position. Corticocancellous bone graft is placed around the base and the distal osteotomy sites with fibrin glue for

hemostasis and P.408 to promote healing. The fibular bone graft is taken through a separate incision with separate instruments in the midportion of the fibula on the same side between the peroneus longus and the soleus interval. The muscles are retracted, and the intermuscular septum is released with the cutting electrocautery. An oscillating saw is used to remove 8 to 10 cm of the fibula. The wound is then irrigated, and the peroneal muscles are repaired. A drain is used. Metatarsophalangeal Joint Amputation A longer plantar flap is planned. The incision is carried out at the level of the metatarsophalangeal joint on the dorsum of the foot. Sharp dissection is used to expose the joint, and the capsule, ligaments, and tendons are cut at that level. The vessels are cauterized. The plantar flap is brought over the dorsal aspect and nylon suture is used to repair the skin.

▪ Transmetatarsal Amputation A transverse incision is made either at the middle or proximal third of the metatarsals, extending through skin into the subcutaneous tissue (TECH FIG 2A). The cutaneous branches of the terminal portions of the peroneal nerve are identified. Traction is applied, pulling the nerve distally. The nerve is transected sharply to allow it to retract proximally. The terminal branch of the dorsalis pedis is preserved, if possible, to maintain continuity of the anastomosis with the posterior tibial terminal arterial branch, thus maintaining the dorsalis pedis contribution of arterial flow through the arch. The extensor tendons are placed on a stretch, and this is best accomplished by flexing the forefoot and sharply dividing the tendons at the level of the skin incision, allowing the tendons to retract proximally. A beveled cut is made in the metatarsal heads by angling an oscillating saw 30 degrees from the perpendicular with the foot placed in neutral position on the operating table. A plantar flap is then fashioned by extending the incision through the skin approximately 45 degrees from the transverse dorsal incision obliquely across the medial and lateral foot to the level of approximately the metatarsal heads and then transversely across the skin just proximal to the metatarsal heads (TECH FIG 2B).

TECH FIG 2 • Surgical technique for transmetatarsal amputation. A. Dorsal and plantar skin incisions. B. Bone cuts are made with a sagittal saw. The sensory nerve to the first ray is identified, traction is placed, and the nerve is transected sharply. The terminal branches in the medial plantar nerve are identified as well, placed on stretch, and sharply divided. The terminal branches of the medial plantar artery are identified, ligated, and divided. The superficial and deep flexor tendons are placed on stretch by dorsiflexing the forefoot through the metatarsal osteotomies and sharply dividing them, allowing them to retract proximally. No attempt is made to suture the extensor tendons to the flexor tendons. P.409 If there is a significant plantar extension of the tumor, a long plantar flap cannot be used. In this case, a fish-mouth configuration is preferable. To achieve this, equal dorsal and plantar flaps are constructed and the same operation is carried out as indicated earlier. The tourniquet is deflated and meticulous hemostasis is obtained. Excessive use of cautery to obtain hemostasis is discouraged to limit dysvascularity of the plantar flap. The plantar flap is brought up and myodesed to the residual metatarsals or tarsal bones. Alternatively, the plantar fascia can be sewn into the periosteum overlying the residual metatarsal heads or capsular structures in and around the tarsal bones. The skin is closed with 4-0 nylon sutures. A Penrose drain is placed deep to the flap and brought out either medially or laterally through the incision.

▪ Lisfranc Amputation A transverse incision is made either at the middle or proximal third of the metatarsals, extending through

skin into the subcutaneous tissue. The cutaneous branches of the terminal portions of the peroneal nerve are identified. Traction is applied, pulling the nerve distally. The nerve is transected sharply to allow it to retract proximally. The terminal branch of the dorsalis pedis artery is ligated and divided as it enters the first dorsal interspace and courses in the plantar fascia. The extensor tendons are placed on a stretch; this is best accomplished by flexing the forefoot and sharply dividing the tendons at the level of the skin incision, allowing the tendons to retract proximally. The Lisfranc joint is disarticulated sharply. A plantar flap is fashioned by extending the incision through the skin approximately 45 degrees from the transverse dorsal incision obliquely across the medial and lateral foot to the level of the distal metatarsals (TECH FIG 3A). The sensory nerve to the first ray is identified, traction is placed, and the nerve is transected sharply. The terminal branches in the medial plantar nerve are identified, placed on stretch, and sharply divided.

TECH FIG 3 • Surgical technique for Lisfranc amputation. A. Skin incisions are made on the dorsal and plantar aspects of the foot, and the metatarsals are dissected and removed. The plantar skin flap is longer. B. Wound closure with sutures. The terminal branches of the medial plantar artery are identified, ligated, and divided. The superficial and deep flexor tendons are placed on stretch by dorsiflexing the forefoot through the Lisfranc joint and sharply dividing them, allowing them to retract proximally. No attempt is made to suture the extensor tendons to the flexor tendons. If there is a significant plantar extension of the tumor, a long plantar flap cannot be used. In this case, a fish-mouth configuration is preferable. To achieve this, equal dorsal and plantar flaps are constructed and the same operation is carried out as indicated earlier. The tourniquet is deflated and meticulous hemostasis is obtained. Excessive use of cautery to obtain hemostasis is discouraged to limit dysvascularity of the plantar flap. The plantar flap is brought up and myodesed to the tarsal bones. Alternatively, the plantar fascia can be sewn into the periosteum overlying the capsular structures in and around the tarsal bones. The skin is closed with 4-0 nylon sutures (TECH FIG 3B), and a small drain is placed deep to the flap and brought out either medially or laterally through the incision. P.410

▪ Chopart Amputation The Chopart amputation is performed through a transverse incision that is dorsally based at or just distal to the talonavicular joint (TECH FIG 4A).

The dorsalis pedis artery and accompanying nerve are identified. The dorsalis pedis artery is ligated and divided, and the sensory nerve is placed on stretch and transected sharply, allowing it to retract proximally. The capsule of the talonavicular joint is circumferentially divided, along with release of the posterior tibial tendon. This tendon is tagged for later use as it is brought through the interosseous membrane and reattached to the neck of the talus with suture anchors or through a hole drilled in the talus as described earlier. An alternative solution is to place the posterior tibial tendon through the interosseous membrane with the medial half of the Achilles tendon. The Achilles tendon is then suture- anchored to the neck of the talus and used to augment the tibialis anterior or posterior tibial tendon. Achilles lengthening is also a helpful technique because it reduces the stress on the tibialis anterior. The Achilles tendon is not necessary for normal ambulation due to the lack of forefoot. A long plantar flap is preferred, but if the tumor extends into the plantar base and soft tissues, a fishmouth incision is made with equal length dorsal and plantar flaps. To help prevent equinus contracture, the tibialis anterior is detached from the tarsal navicular with a cuff of soft tissue, preferably periosteum. A drill hole is made through the neck and head of the talus in an oblique fashion from dorsolateral to plantar medial. The tendon is then routed through this bone tunnel and sewn to itself or soft tissue as it exits through the tunnel (TECH FIG 4B). This repair may be augmented with bone anchors placed near the dorsal opening of the tunnel. The residual foot is maintained in maximal dorsiflexion during this repair. TECH FIG 4C shows the position of the ankle after the amputation and reconstruction of the tibialis anterior into the talus. Several additional procedures are required for a functional Chopart amputation. Contracture prevention is critical and ensured through transfer of the extensor tendons to the dorsum of the foot and lengthening of the Achilles tendon.7

TECH FIG 4 • Surgical technique for Chopart amputation. A. Skin incisions with dorsal and plantar flaps. Bones are dissected and removed. B. Attachment of tibialis anterior tendon into the neck of the talus through drill holes. Wound closure with sutures. C. Chopart amputation has a poor reputation because equinus contracture develops in many patients. With transfer of the tibialis anterior to the neck of the talus, this problem can be avoided. This patient also had a bupivacaine catheter placed for postoperative pain control. The posterior tibial tendon and the flexor hallucis longus and brevis tendons are divided; the tendons are allowed to retract proximally unless the posterior tibial tendon is used to augment the dorsiflexion repair. The plantar branch of the posterior tibial artery is located, ligated, and divided. The flaps are maintained with sufficient soft tissue to keep them as thick as possible to prevent devitalization of the skin. If the head of the talus is prominent, a portion of this bone can be removed in a beveled fashion by using an oscillating saw and angling the blade 30 degrees from distal proximal to plantar distal. The calcaneocuboid articulation is generally divided, but if part of the cuboid can be maintained, this is preferable. Contouring the distal talus and calcaneus will help to decrease the size of the stump, and this will help with prosthetic fitting. The repair of the plantar soft tissue to the dorsal soft tissue is tenuous as there is no stout tissue dorsally to anchor the plantar flap. For this reason, a myodesis is preferred; it is performed by drilling holes in the distal talus and residual cuboid and anchoring the plantar fascia to the dorsal residual bone with 0 nonabsorbable suture. The subcutaneous tissue is approximated with 3-0 absorbable sutures and the skin repaired with 4-0 nylon suture. The residual foot must be maintained in as much dorsiflexion as possible. To help achieve this, a rigid

dressing is applied by binding the residual foot from a proximal-plantar to distal-dorsal direction and applying gentle but firm compression on the residual foot. This rigid dressing is applied and extended up to the proximal leg, maintaining the residual foot and ankle in a maximally dorsiflexed position to protect the repair. P.411

▪ Curettage and Cryosurgery of the Calcaneus Curettage A sciatic nerve catheter is used for intraoperative and postoperative pain control. General anesthesia is used for the procedure. The patient is placed into the lateral decubitus position with the affected side up. A tourniquet is placed on the upper thigh. After sterile surgical preparation and draping, an L-shaped incision is made from the tip of the fibula posteriorly and anterior to the Achilles tendon. The incision is parallel to the fibula, extending distally and making a curve at the border between the dorsal and plantar skin of the calcaneus laterally. The initial skin is incised using the scalpel and dissection is carried down through the subcutaneous tissue. The incision and approach are inferior to the peroneal tendons, which remain safely superior to the dorsal fasciocutaneous flap. The sural nerve is also more superior and away from the operative field. The lateral wall of the calcaneus is exposed. A corticotomy is made using a drill to open the lateral wall of the calcaneus. The tumor is opened, which allows for the curettage. Large curettes are used to remove the obvious tumor material. This is followed by inspecting and burring the edges of the remaining calcaneal wall. Once the resection is completed, the cavity is irrigated to again inspect the cavity for remaining tumor. Cryosurgery The tourniquet is inflated to 350 mm Hg. Gelfoam is used to line the skin edges and subcutaneous tissue around the wound site. The retractors are placed over the Gelfoam, and laparoscopic tape sponges are placed around the skin to cover the skin. The foot is placed into a basin of warm water to try to keep the foot warm to prevent any problems that the decreased temperature from the cryosurgery may cause in the uninvolved portions of the foot. Normal saline is poured into the tumor cavity. Endocare cryosurgery probes are prepared on the back table. Ice balls are formed and noted at the tip of each of the probes. Three- and 5-mm probes are used for the cryosurgery. The cryoprobes are placed into the tumor cavity and left in to complete a 10-minute cycle. The skin is monitored for necrosis, and warm saline is used to keep the skin warm and supple. The cavity is allowed to thaw and the tourniquet is deflated. Reconstruction The reconstruction portion of the procedure consists of an allograft cancellous bone block from the bone tissue bank that is cut and contoured and placed against the subchondral surface adjacent to the subtalar joint. Two small Rush rods are cut, contoured, and placed within the calcaneus to extend from the subtalar joint, abutting and holding the allograft in place. Polymethylmethacrylate (PMMA) is mixed with 1 g vancomycin on the back table and prepared by hand mixing. This is placed into the tumor cavity to fill the cavity, completing the reconstruction.

The midfoot and forefoot are taken through gentle range of motion to ensure normal movement of these joints and to make sure that there was no iatrogenic extrusion of cement, which could compromise the motion of these joints. The calcaneus is gently axially loaded with hand pressure to ensure that the reconstructed calcaneus moves as a single unit. A drain is placed, and the wound is closed in layers. A plaster splint is used.

▪ Syme Amputation The incision extends from the anterior aspect of the lateral malleolus to the anterior aspect of the medial malleolus, continuing to the plantar skin. The incision at the plantar flap is made to the level of the calcaneocuboid joint. The soft tissues, including tendons, are incised and allowed to retract; the neurovascular bundle is identified and ligated. The talus and calcaneus are dissected sharply and removed. The surgeon must be cautious at the point of the Achilles tendon insertion site: The skin is thin and adherent and must be protected. The flares of the malleoli are removed with a sagittal saw. The plantar fat pad is fixed to the end of the stump with nonabsorbable sutures into drill holes of the distal tibia and fibula. A drain is placed and the wound closed in layers; 3-0 nylon suture is used to repair the skin. A wellpadded soft dressing is applied.

P.412

PEARLS AND PITFALLS Indications

▪ A careful and complete history and physical examination are essential. Preoperative studies are necessary to plan the resection and reconstruction.

Surgical incision

▪ A long plantar flap results in a better end-bearing stump. The natural cascade of metatarsal lengths should be maintained.

Wound healing complications

▪ Local wound care with dressings and oral antibiotics are usually sufficient to allow for healing.

Deep infection

▪ Parenteral antibiotics and surgical débridement may be necessary to treat deep infections. Early diagnosis and treatment can affect outcome.

Contractures

▪ Postoperative splinting can help prevent contractures. Once a contracture occurs, it is treated with stretching if mild. Serial casting may be needed.

Painful stump

▪ The end of the bones should be contoured to be smooth. A rasp is effective. Adequate soft tissue coverage will help prevent bony prominence, which may become symptomatic.

POSTOPERATIVE CARE Postoperative pain control will allow early mobilization of the patient. Wound healing without complications and prevention of contractures, particularly equinus contractures, are vital.1 After a ray resection, the patient is placed in a well-padded splint. Crutches are used until the sutures are removed. The patient may begin range-of-motion exercises and weight bearing as tolerated. Toe amputation patients may ambulate in a postoperative shoe immediately. The sutures are removed at 2 to

3 weeks. A wide comfort shoe is worn and activities are progressed as tolerated. For the Lisfranc and transmetatarsal amputations, a rigid postoperative dressing is used. The wound is dressed with nonadherent dressing gauze. A gauze roll is used to bind the residual foot. Cotton padding is then placed in strips from the hindfoot to the forefoot from plantar to dorsal in an attempt to reduce the tension on the suture line. The heel is well padded with cotton padding, and then a plaster cast is applied. The cotton padding may have elastic in it for built-in stretch. The plaster is also applied from proximal and plantar to distal and dorsal to reduce the tension on the suture line. The plaster application should be firm but not tight. It should be placed in closed-toe fashion and should extend up to the proximal leg, maintaining the residual foot in the neutral position to a slightly dorsiflexed position. This initial dressing is changed after 3 to 5 days and the Penrose drain is removed with the first dressing change. A similar plaster is applied for an additional 2 weeks. At the time of plaster removal, the sutures are removed. The patient is given a prescription for a shoe filler. After 2.5 weeks, the patient's foot is placed in a bucklewedge shoe for an additional 3 to 4 weeks. After that, shoe wear and progressive ambulation are encouraged. After a Chopart amputation, the cast is removed after 5 days and the drain is removed. A second dressing and cast are applied for about 3 weeks. The second cast is removed and the sutures are removed at the end of the 3 weeks. A third cast is applied and maintained for 6 to 8 weeks. After the final cast is removed, the patient begins physical therapy to begin range of motion, in particular dorsiflexion and plantarflexion excursion of the residual foot. A prosthetic measurement is taken.

OUTCOMES After a toe amputation at the level of the metatarsophalangeal joint, full preoperative function is regained. A cosmetic toe prosthesis may be used if the patient desires one, but it has no functional purpose. Ray resection outcomes depend on the number of rays amputated and whether the first ray is involved. A ray resection of the second, third, fourth, or fifth metatarsal does not need shoe modification with a molded insert or filler. Generally, ordinary store-bought shoes that are wide and have adequate cushioning are worn. A first ray resection affects the remaining foot function because of loss of the windlass mechanism. Reconstruction of the first ray would prevent this problem (FIG 8). Removal of two central rays will leave a narrower foot and shoe-wear problems. Patients with a metatarsal ray or transmetatarsal amputation have better outcomes than patients with a Syme amputation.8 Patients with a Lisfranc, transmetatarsal, or Chopart amputation have good overall function compared with patients with a Syme amputation.1,13,16 However, patients with an equinus contracture after a Chopart amputation have inferior results.8,10

FIG 8 • This patient had a recurrent giant cell tumor of the first metatarsal that was treated successfully with a fibular strut graft. This lateral radiograph shows the healed graft 7 years postoperatively. P.413 A Chopart amputation in a young patient is inferior in function to a Syme amputation due to the lack of ability to replace forefoot function when the space between the floor and the plantar surface is reduced significantly in a Chopart amputation. The Chopart procedure provides an excellent level of amputation for a patient with limited activities and goals.1 The main advantage to this level is that little is lost between the distal end of the residual limb and the floor. This allows ease of ambulation without the need for a prosthetic device.15 For persons requiring short trips to the bathroom in the middle of the night or stability for transfers, the Chopart level is perfect. Unfortunately, the lack of anatomic structure and minimal distance from the plantar surface to the floor makes the Chopart amputation a poor choice for the active amputee. Ambulation is achieved with a foot spacer. For the Chopart stump, a clamshell type of prosthesis allows good weight-bearing function and restores the effective foot length.6 Generally, patients are able to ambulate 3 months after amputation using a simple shoe prosthesis.16 Gait analysis shows that abnormality and asymmetry of ground-reaction forces were less with a greater preserved stump length.11

COMPLICATIONS Wound healing complications are treated with local wound care, elevation, and non-weight bearing. Oral antibiotics may be indicated. If there is skin flap necrosis, débridement with a skin graft may be

necessary.3 Superficial infection is often resolved with a short course of oral antibiotics. Deep infection may require immediate operative débridement of devitalized tissue. Parenteral antibiotics are important to treat this limb-threatening problem. At the time of the débridement, a bone culture should be ordered to help determine the appropriate antibiotic. Equinus contracture is most easily treated by prevention. However, stretching with a therapist may be helpful. Serial casting may be required to correct the deformity.

REFERENCES 1. Berke GM. Lower limb prosthetics. In: Coughlin MJ, Mann RA, Saltzman CL, eds. Surgery of the Foot and Ankle, ed 8. Philadelphia: Mosby, 2007:1399-1422. 2. Bugnone AN, Temple HT, Pitcher JD. Low-grade central osteosarcoma of the foot and ankle: radiographic and pathologic features in two patients: case report and literature review. Foot Ankle Int 2005;26:494-500. 3. Chang BB, Bock DE, Jacobs RL, et al. Increased limb salvage by the use of unconventional foot amputations. J Vasc Surg 1994;19:341-349. 4. Choong PF, Qureshi AA, Sim FH, et al. Osteosarcoma of the foot: a review of 52 patients at the Mayo Clinic. Acta Orthop Scand 1999;70:361-364. 5. Chou LB, Malawer MM. Analysis of surgical treatment of 33 foot and ankle tumors. Foot Ankle Int 1994;15:175-181. 6. Dillon MP, Barker TM. Can partial foot prostheses effectively restore foot length? Prosthet Orthot Int 2006;30:17-23. 7. Garbalosa JC, Cavanagh PR, Wu G, et al. Foot function in diabetic patients after partial amputation. Foot Ankle Int 1996;17:43-48. 8. Greene WB, Cary JM. Partial foot amputations in children: a comparison of the several types with the Syme amputation. J Bone Joint Surg Am 1982;64A:438-443. 9. Hattrup SJ, Amadio PC, Sim FH, et al. Metastatic tumors of the foot and ankle. Foot Ankle 1988;8:243247. 10. Heim M. A new orthotic device for Chopart amputees. Orthop Rev 1994;23:249-252. 11. Hirsch G, McBride ME, Murray DD, et al. Chopart prosthesis and semirigid foot orthosis in traumatic forefoot amputation: comparative gait analysis. Am J Phys Med Rehabil 1996;75:283-291. 12. Kirby EJ, Shereff MJ, Lewis MM. Soft-tissue tumors and tumor-like lesions of the foot: an analysis of eighty-three cases. J Bone Joint Surg Am 1989;71A:621-626.

13. Millstein SG, McCowan SA, Hunter GA. Traumatic partial foot amputations in adults: a long-term review. J Bone Joint Surg Br 1988;70B:251-254. 14. Murari TM, Callaghan JJ, Berrey BH Jr, et al. Primary benign and malignant osseous neoplasms of the foot. Foot Ankle 1989;10:68-80. 15. Philbin TM, Leyes M, Sferra JJ, et al. Orthotic and prosthetic devices in partial foot amputations. Foot Ankle Clin 2001;6:215-228. 16. Roach JJ, Deutsch A, McFarlane DS. Resurrection of the amputations of Lisfranc and Chopart for diabetic gangrene. Arch Surg 1987;122:931-934. 17. Seale KS, Lange TA, Monson D, et al. Soft tissue tumors of the foot and ankle. Foot Ankle 1988;9:19-27. 18. Sundberg SB, Carlson WO, Johnson KA. Metastatic lesions of the foot and ankle. Foot Ankle 1982;3:167-169. 19. Wetzel LH, Levine E. Soft-tissue tumors of the foot: value of MR imaging for specific diagnosis. AJR Am J Roentgenol 1990;155:1025-1030. 20. Wu KK, Guise ER. Metastatic tumors of the foot. South Med J 1978;71:807-812.

Chapter 37 Above-Knee Amputation Daria Brooks Terrell

BACKGROUND Although many bone and soft tissue sarcomas of the femur and thigh can be treated with limb-sparing techniques, some aggressive tumors are complicated by neurovascular involvement or extensive soft tissue contamination and thus require an above-knee amputation (AKA) (FIG 1). An AKA is a transfemoral amputation of the lower extremity. AKAs are usually classified by level: high (just below the lesser trochanter), standard or midfemur (diaphyseal), or low distal femur (supracondylar). In general, transfemoral amputations with 50% to 70% of the residual bone length (measured from the greater trochanter to the lateral femoral condyle) are optimal. However, when amputations are done in an oncologic setting, the amount of femur remaining is determined by the extent of the tumor. Generally, if 3 to 5 cm of bone distal to the lesser trochanter remains, a standard AKA prosthesis can still be used.

ANATOMY The surgeon must be familiar with the major neurovascular structures of the thigh because these structures will need to be identified and ligated. The femoral artery is the main artery of the thigh and femur. Its course changes throughout the length of the femur and, therefore, its location varies depending on the level of amputation (FIG 2).

FIG 1 • Primary bone sarcoma of the distal femur with a soft tissue (extraosseous) component can be treated with limb-sparing surgery and endoprosthetic reconstruction (A) or amputation (B). C. AKA for an osteosarcoma

of the distal femur, performed in the early 1960s. Because of the lack of accurate imaging modalities at that time, the extent of the soft tissue component and the relation of the tumor to the neurovascular bundle were assessed in surgery using a large incision and only then was the decision to proceed with an amputation made.

High Above-Knee Amputation Proximally, the femoral artery lies beneath the sartorius muscle, anterior to the adductor longus muscle, and anterior to the femur. The profunda femoris artery lies posterior to the adductor longus muscle. At this level, the femoral artery is lateral to the femoral vein. The sciatic nerve lies posterior to the adductor magnus and anterior to the long head of the biceps.

Midfemur Above-Knee Amputation The femoral artery lies between the vastus medialis and the adductor magnus and is medial to the femur in the midthigh area. In this region, the femoral vein is lateral to the artery. The sciatic nerve lies between the short head of the biceps and the semimembranosus. P.415

FIG 2 • Level of osteotomy and cross-sectional anatomy for supracondylar, diaphyseal, and high AKA. (Courtesy of Martin M. Malawer.)

Supracondylar Above-Knee Amputation The femoral artery is directly posterior to the femur. After passing the canal of Hunter, the femoral artery joins the sciatic nerve in the popliteal fossa. The artery is deep and medial to the sciatic nerve.

FIG 3 • A. A 45-year-old patient initially presented with a dedifferentiated, highgrade osteosarcoma of the fibula. After neoadjuvant chemotherapy, the patient underwent intercalary fibular resection. Approximately a year after the surgery, the patient presented with a rapidly enlarging, extensive tumor recurrence. B. As shown on MRI, the tumor extensively invaded the superficial posterior, deep posterior, and lateral compartments of the leg. Wide excision of the tumor would necessitate removal of the neurovascular bundle and all three compartments. AKA was therefore performed.

INDICATIONS Local recurrence of malignant carcinoma or sarcoma where limb salvage would not yield a functional limb or effectively remove the disease (FIG 3A) Tumors with major vascular involvement with invasion of major blood vessels, which usually have poor outcomes and a poor prognosis (FIG 3B) Soft tissue contamination, such as after a pathologic fracture Tumors of the distal lower extremity with major nerve involvement, as with tumors of the popliteal space (FIG 4A,B) A poorly planned and executed biopsy, which can cause extensive contamination Infection, particularly in the case of tumor ulceration Skeletal immaturity, which often leads to significant limb length discrepancies when limb-sparing procedures are done on skeletally immature patients Extensive tumor involvement that prohibits adequate soft tissue coverage of a prosthesis (FIG 4C-E)

IMAGING AND OTHER STAGING STUDIES Plain Radiography

Plain radiographs often provide the first indication for the need for amputation and an initial estimate of the necessary amputation level. Orthogonal views of the femur, tibia, and fibula can be helpful in showing tumor involvement and the extent of bony destruction, although, generally, up to 30% of the bony architecture has to be destroyed before radiographic findings are apparent (FIG 5A). P.416

FIG 4 • A,B. A 77-year-old patient presented with a high-grade soft tissue sarcoma that invaded the popliteal space and destroyed the proximal and midshaft areas of the tibia and fibula, resulting in the loss of peroneal function. C. A 23-year-old patient with a few years' history of a neglected benign giant cell tumor of the distal femur with an extensive soft tissue component. D. A plain radiograph of the distal femur showing extensive bone destruction. The knee joint is in flexion contracture due to intractable pain. E. CT shows that only a thin rim of muscles is left. Adequate soft tissue coverage of a prosthesis was therefore not feasible and AKA was performed. (C-E: Courtesy of Martin M. Malawer.)

FIG 5 • A. Plain radiograph of the knee showing extensive destruction of the proximal tibia and fibula. B. CT scan showing a large tumor that displaced the popliteal artery posteriorly and obliterated branches of the popliteal artery more distally. P.417

Computed Tomography and Magnetic Resonance Imaging Computed tomography (CT) and magnetic resonance imaging (MRI) are the most helpful in determining the level of intramedullary tumor involvement and the extraosseous extent of the tumor, which is used to determine the amputation level (FIG 5B). MRI is also useful for showing tumor involvement of neurovascular structures, which often necessitates amputation. MRI is the most reliable imaging study in determining the presence of skip metastases, which may alter the level of amputation.

Bone Scan Bone scans are useful in determining the intraosseous extent of the tumor; findings correlate well with the MRI.

Angiography and Other Studies Angiography is useful in determining the patency of the major vessels. In the older population, the superficial femoral artery is often obliterated.

Biopsy A biopsy is necessary before determining the final level of amputation. In general, transmedullary amputation is now performed for bony sarcomas of the distal femur, although historically, a hip disarticulation was recommended. A failed limb-sparing procedure of the distal femur can still be treated with a high AKA.

SURGICAL MANAGEMENT When AKAs are done for oncologic indications, the tumor extent ultimately determines the level of amputation. Beyond that consideration, retaining as much length as possible that is closest to the ideal stump length will facilitate prosthetic fitting. The types of flaps may vary depending on the extent of the distal femoral tumor; medial lateral flaps may be required instead of the more traditional fish-mouth incision. The quality of the skin, prior radiation, and old scars must all be considered. In general, we do not use immediate-fit prostheses after amputation for tumors. When planning the types of flaps that will be used for the amputation, the surgeon should consider the soft tissue extent of the tumor, prior radiation fields, and previous incisions.

Preoperative Planning Having patients meet with a prosthetist, a functional amputee, or both can help manage expectations and answer specific questions about daily activities and function.

Positioning Patients are placed supine on the operating table with the operative extremity in flexion and abduction (FIG 6).

Approach Most amputations are done initially using an anterior approach to the femur. The leg can then be placed in a figure-4 position and then flexed and adducted to facilitate the posterior work.

FIG 6 • The patient is supine; the operated extremity is in flexion and abduction. (Courtesy of Martin M. Malawer.)

TECHNIQUES

▪ Incision and Transection of Muscle, Neurovascular Structures, and Bone The most common type of flap is the anterior and posterior fish-mouth flap. This type of incisional line should be drawn before starting the procedure. The initial incision is made through the skin, superficial fascia, and subcutaneous tissue vertical to the skin edges (TECH FIG 1A). The major muscles should be carefully transected using electrocautery to reduce bleeding and tacked for later use in soft tissue reconstruction. The level of the amputation will determine the muscles that are transected, but portions of the quadriceps, hamstrings, and adductors are cut at almost all levels (TECH FIG 1B). The deep femoral artery and vein are dissected, suture ligated, and transected. Nerves should be pulled gently about 2 cm, ligated with nonabsorbable sutures, and transected with a knife. The sutures can be used later to identify the femoral and sciatic nerves if epineural catheters are to be placed. If the catheters are not placed, the nerves should be allowed to retract back to the muscle mass. The bone is cut using an oscillating or Gigli saw. A malleable retractor placed posterior to the femur can prevent damage to the posterior soft tissue and flap. Once the bone is cut, frozen section analysis from the remaining intramedullary canal is performed to ensure that there is no tumor remaining. The femoral edge is beveled using a saw or rasp to smooth the remaining edge and to leave a less prominent point of contact for the prosthesis (TECH FIG 1C,D). P.418

TECH FIG 1 • A. Incision. The skin flaps are marked. The main factors that determine the type of flaps are the extent of the soft tissue tumor, areas of prior radiation, and previous scars. The highest priority is to avoid local recurrence and no attempt is made to adhere to standard flaps; at this level, a skin or muscle flap of almost any length will heal primarily in a young patient. It is not necessary to use equal flaps; long posterior, anterior, and medial flaps will heal. B. Transection of muscle and bone. Incision is performed through the skin, superficial fascia, and subcutaneous tissue vertical to the skin edges. Using electrocautery, muscles are beveled in their transection down to bone. Large vessels are dissected, sutureligated in continuity, and transected in a bloodless fashion. Nerves should be gently pulled down from their muscular bed approximately 2 cm, ligated with nonabsorbable monofilament sutures, transected with a knife, and allowed to retract back to the muscle mass. The bone is transected with an oscillating or Gigli saw without traumatizing the soft tissues. C. The femoral edge should be beveled and smooth. D. A sharp edge can become extremely painful, especially when pressure from a prosthesis is applied. (Courtesy of Martin M. Malawer.)

▪ Placement of Epineural Catheter and Myodesis

A small opening is made using a no. 15 blade scalpel into the epineural sheath. An epineural catheter, which has previously been flushed with 0.25% bupivacaine, is introduced into the epineural space and advanced proximally for 5 to 7 cm. The neural sheath is then closed with 4-0 chromic suture (TECH FIG 2A,B). A 16-gauge angiocatheter is introduced into the skin at the desired site of exit for the epineural catheter. The epineural catheter is threaded through the angiocatheter until it is visible beyond the skin. The angiocatheter, encasing the epineural catheter, is carefully brought through the subcutaneous tissue to exit at the skin (TECH FIG 2C). To prevent flexion and abduction of the femoral stump, drill holes can be made in the femur using a standard drill, and then the sutures P.419 used to tag the adductor musculature can be threaded through the femoral holes to tenodese the adductors to the femur. This also helps restore some of the muscular strength (TECH FIG 3A).

TECH FIG 2 • A. An silastic catheter, flushed with bupivacaine 0.25%, is introduced into the epineural space. The catheter is advanced 5 to 7 cm proximally and the neural sheath is sutured over the catheter with absorbable sutures. B. An epineural catheter in the femoral nerve after AKA. Contrast dye was bolus injected to show the distribution of local anesthetics within the epineural space. C. Intraoperative clinical photograph demonstrating the placement of surgical drain and perineural catheter at the distal and

proximal ends (respectively) of the AKA stump. (Courtesy of Martin M. Malawer.) We recommend excising some of the adductors before myodesis to shape the stump into a nice conical shape. Additional muscle may be resected from the lateral aspect of the thigh if necessary.

TECH FIG 3 • A. A two-layer myodesis is used over the end of the femur. Muscle stabilization of the femur is essential if the strength of the limb is to be retained. The quadriceps and hamstring muscles are myodesed to each other to cover the bony end of the femur, and the adductors are tenodesed to these muscles and the femoral stump using drill holes. This is especially important if there is a short proximal femoral stump, which tends to go into flexion and abduction. B. Myodesis of the remaining musculature over the amputation stump. A plug of polymethylmethacrylate (PMMA) or Gelfoam is placed in the distal canal to prevent large hematomas from occurring due to continuous intraosseous bleeding after surgery. This is more common in young adults and children. The remaining quadriceps and hamstring muscles are myodesed to each other to cover the end of the femur (TECH FIG 3B). P.420

▪ Drain Placement and Closure Closed suction drains placed beneath the fascial layer should be brought out of the medial and lateral aspects of the incision (TECH FIG 4A,B). The superficial fascia should be tightly closed. As the skin edges are closed, the surgeon should take care to avoid having excess tissue and large skin folds, which can later interfere with optimal prosthetic fitting.

TECH FIG 4 • A. Closed suction drains are brought out of the medial and lateral aspects of the incision. It is important not to stitch these catheters to the skin because they will be removed from inside the rigid dressing. B. In cases in which wound healing is problematic, a vacuum-assisted closure (VAC) device can be used with great success. C. Application of a rigid dressing. (Courtesy of Martin M. Malawer.) A rigid dressing should be applied at the completion of the amputation to reduce swelling and prevent the development of a flexion contracture (TECH FIG 4C).

PEARLS AND PITFALLS Postoperative flexion contracture

▪ Flexion contractures can be prevented with the use of proximal casting or immobilization to the groin level, suspended in place with a belt, if necessary.

Adductor myodesis

▪ After AKA, the iliopsoas and hip abductors can cause the stump to go into flexion and abduction. Tenodesing the adductor magnus prevents this deformity and helps prevent the loss of hip adduction power, which has been estimated to be up to 70% less without myodesis. Myodesis acts as an insertion site and facilitates muscle contraction and function.

Muscle balance

▪ Managing muscle group imbalances through myoplasty also improves the function of the amputee. Because the hip flexors are stronger than the extensors, the hamstrings should be cut longer than the quadriceps and attached to one another.

Neuroma

▪ Nerves should be cut as proximally as possible and buried within muscular tissue to prevent neuroma formation.

Phantom pain

▪ The use of epineural catheters in the femoral and sciatic nerves can decrease the incidence and severity of phantom pain.

Skin pressure from bone edges

▪ The distal anterior cortical edge of the femur should be beveled to prevent pressure arising from the bone, particularly with prosthetic use.

P.421

POSTOPERATIVE CARE A compressive dressing applied to the stump site diminishes postoperative swelling at the stump site. Proximal extension of the postoperative immobilizer or splint, prone positioning, and physical therapy help to prevent flexion contracture. Fitting for an initial or temporary prosthesis soon after wound healing and swelling resolution is most often associated with increased prosthetic use. Because the energy requirements of AKAs are about 60% to 100% times greater than that required for nonamputees, many amputees require the use of assistive devices for ambulation. Phantom limb pain and sensations can diminish after surgery. However, when phantom pain persists, narcotics and drugs with effects on nerves such as gabapentin (Neurontin) may be helpful.

OUTCOMES Through effective multidisciplinary care, most patients are able to ambulate and return to normal daily activities, including driving. Some are also able to participate in sporting activities. Outcome studies comparing patients treated with amputations versus those treated with limb salvage found that AKA amputees were more limited in their mobility and community activities compared to those with limb salvage, but they reported less muscle weakness. In general, AKA amputees have approximately the same overall quality of life compared to patients undergoing limb-sparing surgery when assessed by numerous psychological measures (FIG 7). AKA amputees have also been shown to be more likely to walk with a limp.

COMPLICATIONS Wound healing problems can arise but are not as common as in amputations performed for vascular or ischemic problems. Wound problems after amputations performed for tumors are most likely due to preoperative host factors such as comorbidities and nutritional status. Therefore, the patient's preoperative status should always be optimized where possible.

FIG 7 • Many patients opt for a highly sophisticated above-knee prosthetic following rehabilitation. This computerized knee component allows for a more natural gait in patients, whereas previous generations of prostheses required patients to actually think about the motion of each step that they were taking. Patients with this prosthetic can also change walking speeds more readily if required. Phantom pain or causalgia syndromes may occur and are difficult to predict, although patients with significant preoperative pain complain of postoperative pain more often. Attempts at preventive anesthesia (eg, serial epidurals before surgery) have produced mixed results. It is important to identify and diagnose these painful syndromes early and manage them aggressively.

SUGGESTED READINGS 1. Davis AM, Devlin M, Griffin AM, et al. Functional outcome in amputation versus limb sparing of patients with lower extremity sarcoma: a matched case-control study. Arch Phys Med Rehabil 1999;80:615-618.

2. Ferrapie AL, Brunel P, Besse W, et al. Lower limb proximal amputation for a tumour: a retrospective study of 12 patients. Prosthet Orthot Int 2003;27:179-185. 3. Paradasaney PK, Sullivan PE, Portney LG, et al. Advantage of limb salvage over amputation for proximal lower extremity tumors. Clin Orthop Relat Res 2006;444:201-208. 4. Sugarbaker P, Malawer M. Hip disarticulation. In: Malawer MM, Sugarbaker PH. Musculoskeletal Cancer Surgery: Treatment of Sarcomas and Allied Diseases. Boston: Kluwer, 2001: 351-362. 5. van der Windt DA, Pieterson I, van der Eijken JW, et al. Energy expenditure during walking in subjects with tibial rotationplasty, above-knee amputation, or hip disarticulation. Arch Phys Med Rehabil 1992;73:11741180.

Chapter 38 Below-Knee Amputation Daria Brooks Terrell

BACKGROUND Extensive tumors of the distal leg, ankle, and foot often require a below-knee amputation (BKA) as the primary form of surgical treatment. With such extensive tumors in these locations, attempts at limb salvage often leave patients with a limb with very limited function. Conversely, advances in prosthetic design and engineering allow for BKA amputees to be very active in a variety of activities, often more active than patients who have had limb-sparing procedures for similar tumors. In general, we recommend BKAs for most high-grade and many low-grade sarcomas of the foot, especially when they occur in the plantar aspect. About 1% of bone sarcomas occur in the foot; these are usually treated with a BKA (FIG 1).

ANATOMY The main anatomic focus of a BKA is identification and ligation of the tibial neurovascular structures. The anterior tibial artery and vein and deep peroneal nerve lie deep to the anterior tibialis muscle and lateral to the tibia. These structures must be identified and individually ligated. As the dissection progresses posteriorly, the posterior tibial artery and vein and tibial nerve are found posterior to the tibia and tibialis posterior muscle and anterior to the soleus muscle. The peroneal artery and veins also lie posterior and lateral to the tibia. They lie between the tibialis posterior and the flexor hallucis longus. The superficial peroneal nerve is identified within the lateral compartment of the leg and also must be transected. It usually exits the fascia of the anterolateral leg approximately 12 cm proximal to the tip of the lateral malleolus. It should be identified and transected.

INDICATIONS Tumor recurrence in the distal tibia, ankle, and foot not amenable to limb salvage techniques (FIG 2) Infiltrative high-grade soft tissue sarcomas or other malignant tumors of the lower extremities Extensive involvement of bone sarcomas of the lower extremities Palliation Failed attempt of radiation therapy for dorsal and plantar foot tumors

IMAGING AND OTHER STAGING STUDIES Plain Radiography Although plain radiographs are poor at identifying soft tissue tumors of the foot and ankle, they can be useful for the initial diagnosis of bone tumors such as enchondromas, giant cell tumors, and primary sarcomas of bone (FIG 3A).

Computed Tomography and Magnetic Resonance Imaging Computed tomography and magnetic resonance imaging (MRI) are helpful in determining the level of intramedullary tumor involvement and the extraosseous extent of the tumor, which is used to determine the amputation level. MRI is also useful for showing tumor involvement of neurovascular structures, which often necessitates amputation (FIG 3B).

Bone Scanning Bone scans are required if the tumor is located at or above the ankle. This study correlates well with the MRI. In general, amputation is performed 4 to 7 cm above abnormal findings on a bone scan.

Angiography and Other Studies Angiography is very helpful in determining the extent of involvement of the anterior tibialis and posterior tibialis arteries. Tumor involvement of either of these structures determines the type of flap that should be used. This planning is important in minimizing wound healing problems.

Biopsy As with an amputation at any level, a biopsy should be done to confirm the diagnosis before performing a BKA.

SURGICAL MANAGEMENT The ideal level of surgical resection for a BKA is at the musculocutaneous junction of the gastrocnemius muscle. This provides better soft tissue padding and usually a more reliable blood supply for the posterior flap. The recommended length for a BKA stump for optimal prosthetic fitting is 12.5 to 17.5 cm. However, tumor extent and margins will ultimately determine the length of the stump. Careful flap selection is important in achieving a functional BKA stump. Because of the subcutaneous location of the tibia and sparse musculature of the anterior leg compartment, use of a long posterior flap is preferable to a fishmouth flap. Prevention of hematoma and seroma development with the use of drains is critical. These complications can delay wound healing and, in some cases, delay adjunctive treatments such as chemotherapy and radiation therapy. P.423

FIG 1 • BKA is performed for malignant tumors of the distal leg, ankle, and foot. (Courtesy of Martin M. Malawer.)

FIG 2 • A. Locally recurrent carcinoma of the foot. This local recurrence, the patient's fifth, occurred only a few months after the previous resection within the irradiated field. B. Extensive high-grade angiosarcoma of the dorsal aspect of the foot. (Courtesy of Martin M. Malawer.)

FIG 3 • A. Angiosarcomatosis of the leg and foot. There are multiple lytic lesions of the distal third of the tibia, fibula, and talus. B. T2-weighted magnetic resonance image of the foot, showing extensive high-grade malignant fibrous histiocytoma of almost the entire plantar aspect of the foot, with extension to the dorsal aspect of the foot. P.424

Preoperative Planning Preoperative referrals to a psychologist and prosthetist are often useful in helping patients prepare for their upcoming life adjustments.

Positioning The patient is supine on the operating table with the operative extremity slightly elevated.

Approach The initial approach is made anteriorly in most cases. Then the knee can be flexed and abducted and adducted or an assistant can elevate the leg to gain exposure for the posterior work.

TECHNIQUES ▪ Incision and Flap Selection, Soft Tissue Dissection, and Bone Transection Because of the subcutaneous location of the tibia and the minimal musculature of the anterior leg compartment, a long posterior flap is preferable to the classic fish-mouth flap. In the initial incision, the skin, superficial fascia, and subcutaneous tissue are cut perpendicular to the skin surface (TECH FIG 1A). The muscles of the anterior, lateral, and deep compartments of the leg are transected using the electrocautery to minimize bleeding. The skin, superficial fascia, and subcutaneous tissue are cut perpendicular to the skin surface. The muscles are transected with electrocautery. Vascular structures are ligated in continuity and divided. Major blood vessels are suture-ligated (TECH FIG 1B). Nerves are meticulously dissected and gently

pulled 2 cm out of their surrounding muscle mass. They are doubly ligated with monofilament nonabsorbable suture. The large muscle groups are tapered so that they can be secured over the cut ends of the bone. If the amputation is performed for a primary bone sarcoma, intramedullary content from the edge of the stump should be sent for frozen section to verify that it is free of tumor. If the amputation is performed for a soft tissue sarcoma, soft tissues from the surgical margins should be assessed in a similar manner. After transection, the tibial edge is beveled (TECH FIG 1C,D).

TECH FIG 1 • A. Position and incision. B. Soft tissue dissection and bone transection. C. Osteotomy of the tibia and fibula. D. Intraoperative photo of the resection defect. (continued)

TECH FIG 1 • (continued) E. Radiograph demonstrating bone osteotomies following BKA (arrow). F. Sagittal cut of surgical specimen shows that the entire tibial medulla is occupied by tumor (arrow). Anterior cortical breakthrough and soft tissue extension are evident. (Courtesy of Martin M. Malawer.) The tibia is osteotomized using an oscillating or Gigli saw. The fibula is resected several centimeters proximal to the tibial osteotomy to create a more tapered stump. The cut edge of the tibia is beveled using a saw or rasp to smooth the edges and contour the bone for a better prosthetic fit (TECH FIG 1E). A sample from the remaining intramedullary canal of the tibia should be sent for frozen section analysis to verify that the remaining bone is free of tumor. To form a nice conical stump, we recommend excising the fibula about 4 to 5 cm above the tibial osteotomy, in addition to removing some of the peroneal musculature at the same level. This permits easier stump shrinking and prosthetic fit (TECH FIG 1F). P.425

▪ Placement of Epineural Catheter and Myodesis A small opening is made using a no. 15 blade scalpel into the epineural sheath. The epineural catheter, which has previously been flushed with 0.25% bupivacaine, is introduced into the epineural space and advanced proximally for 5 to 7 cm. The neural sheath is then closed with 4-0 chromic suture. A 16-gauge angiocatheter is introduced into the skin at the desired site of exit for the epineural catheter. The epineural catheter is then threaded through the angiocatheter until it is visible beyond the skin. The angiocatheter, encasing the epineural catheter, is carefully brought through the subcutaneous tissue to exit at the skin.

Using drill holes in the distal tibia, the major muscle groups are attached to the bone with heavy sutures. The remaining muscle layers are used to make a circumferential covering layer over the bony stump (TECH FIG 2).

TECH FIG 2 • Myodesis over the distal tibia. (Courtesy of Martin M. Malawer.)

▪ Drains and Skin Closure Closed suction drains placed beneath the fascial layer are brought out of the medial and lateral aspects of the incision (TECH FIG 3A). The superficial fascia is tightly closed to prevent postoperative wound complications, which could delay prosthetic fitting. The surgeon should avoid having excess tissue and large skin folds during the skin closure, which could interfere with optimal prosthetic fitting. A rigid dressing is applied at the completion of the procedure with the knee in extension to prevent excessive swelling and development of a flexion contracture. After the initial rigid dressing is removed (usually 10 to 14 days following surgery), a stumpshrinker sock can be worn to decrease any remaining swelling (TECH FIG 3B). P.426

TECH FIG 3 • A. Closure of superficial fascia and skin over suction drains. B. Rigid dressing. (Courtesy of Martin M. Malawer.)

PEARLS AND PITFALLS Stump contour

▪ Rounding the contour of the distal end of the tibial stump and resecting the fibula a few centimeters shorter than the tibia can promote better fit and ease with prosthesis use.

Myodesis

▪ Functional myodesis of the major muscle groups of the leg to the distal tibia provides good soft tissue coverage for the stump while allowing functional range of motion.

Wound healing problems

▪ Healing can be compromised by preoperative chemotherapy. The use of drains and attention to detail with wound closures can help avoid these problems as well as hematoma and seroma development, which can delay other adjunctive treatments.

Postoperative flexion contracture

▪ The use of a knee immobilizer or custom splint can prevent the development of a flexion contracture.

Phantom pain and causalgia

▪ Perineural catheter flow rate and dose should be titrated, typically 4-8 mL of 0.25% bupivacaine per hour for about 72 hours.

POSTOPERATIVE CARE

Once the initial postoperative dressing is removed, a stumpshrinker sock can be worn to minimize swelling. Patients should be counseled that the transition to prosthesis use will be slow and gradual and will occur over about 3 to 6 months. Once an initial prosthesis can be fitted, wear time is gradually increased to build tolerance (FIG 4).

OUTCOMES Similar to other lower extremity amputations, BKAs have been shown to be effective in palliation and improving the quality of life in cancer patients. As might be expected, patients after BKAs report less limitations than their AKA counterparts and are less likely to ambulate with walking aids or a limp. The vast improvements in prosthetic design for BKA amputees allow them to be extremely functional. They can participate in almost any desired recreational activity.

COMPLICATIONS Hematoma and seroma develop can cause major wound healing problems that sometimes require additional surgeries. This is a major problem when the amputation has been done for a primary bone or soft tissue sarcoma and adjuvant P.427 chemotherapy is needed. Such wound problems can delay the start of these important treatments and, ultimately, also delay prosthetic fitting.

FIG 4 • A,B. Cosmetic appearance of BKA prothesis. The use of closed suction drains can minimize the risk of such complications.

SUGGESTED READINGS 1. Davis AM, Devlin M, Griffin AM, et al. Functional outcome in amputation versus limb sparing of patients with lower extremity sarcoma: a matched case-control study. Arch Phys Med Rehabil 1999;80:615-618. 2. Paradasaney PK, Sullivan PE, Portney LG, et al. Advantage of limb salvage over amputation for proximal lower extremity tumors. Clin Orthop Relat Res 2006;444:201-208. 3. Sugarbaker P, Malawer M. Hip disarticulation. In: Malawer MM, Sugarbaker PH. Musculoskeletal Cancer Surgery: Treatment of Sarcomas and Allied Diseases. Boston: Kluwer, 2001:363-369.