Dermatologic Surgery: Requisites in Dermatology [1st ed.] 070203049X, 9780702030499

Table of contents :
Front Matter......Page 1
Copyright......Page 2
Dedication......Page 3
Contributors......Page 4
Also in the series......Page 7
Series foreword......Page 8
Volume preface......Page 9
Acknowledgments......Page 10
Topographical landmarks......Page 11
Contour lines and cosmetic units......Page 14
The superficial musculoaponeurotic system (SMAS)......Page 16
Skin tension lines of the face (STLs)......Page 18
The facial nerve and muscles of facial expression......Page 19
The trigeminal nerve......Page 22
The cervical nerves and the posterior triangle of the neck......Page 31
Arterial and venous supply of the face......Page 33
Venous supply of the face......Page 35
The anatomy of the scalp......Page 37
Further reading......Page 49
Classification of wounds......Page 50
Risk factors......Page 51
Antiseptic scrubs......Page 52
Surgical site preparation......Page 54
Patient preparation and hair removal......Page 55
Instrument sterilization......Page 56
Further reading......Page 57
Pain control......Page 0
Structure......Page 58
Classification......Page 59
Systemic effects......Page 60
Cardiovascular......Page 61
Pregnancy and lactation......Page 63
Anesthesia techniques......Page 64
Tumescent anesthesia......Page 66
Scalpel......Page 68
Curettes......Page 69
Scissors......Page 70
Specialty scissors......Page 71
Forceps......Page 73
Needle holders (needle drivers)......Page 75
Hemostats......Page 77
Conclusion......Page 78
Further reading......Page 79
Molecular and cellular biology of wound healing......Page 87
Classification of cutaneous wounds......Page 93
Debridement of wounds......Page 96
Wound dressings......Page 97
Epidermal skin substitutes......Page 100
Optimizing outcomes: wound care guidelines......Page 101
Venous ulcers......Page 102
Pressure ulcers......Page 103
Diabetic ulcers......Page 104
Further reading......Page 105
Electrosurgery adverse reactions......Page 107
Surgical approach (Box 7-2)......Page 108
Controversies......Page 109
Further reading......Page 111
Introduction......Page 112
Techniques......Page 115
Applications......Page 118
Complications......Page 119
Further reading......Page 120
Choosing the appropriate biopsy technique......Page 121
Special diagnostic considerations (Figs 9-1 & 9-2)......Page 122
Scalpel blade (Fig. 9-6)......Page 123
Elliptical incisional/excisional biopsy technique......Page 125
Orienting the ellipse......Page 127
Crescentic excision......Page 131
Specimen removal and undermining......Page 132
Postoperative course and care......Page 137
Complications......Page 138
Further reading......Page 141
General guidelines for suture placement......Page 142
Vertical mattress suture......Page 143
Horizontal mattress sutures......Page 147
Interrupted buried sutures......Page 149
Running subcuticular suture......Page 150
Suture removal......Page 153
Further reading......Page 159
Suture properties......Page 160
Controversies......Page 161
Further reading......Page 165
Definition......Page 166
Classification......Page 167
Flap biomechanics and design......Page 168
Preoperative planning......Page 173
Further reading......Page 182
Technique......Page 184
Postgraft cosmetic considerations......Page 185
Split-thickness grafts......Page 187
Composite grafts......Page 188
Further reading......Page 190
Anatomy......Page 192
Anesthesia......Page 193
Hemostasis......Page 194
Nail avulsion......Page 195
Postoperative management......Page 199
Complications......Page 200
Mohs concepts......Page 201
Mohs preoperative evaluation......Page 203
The procedure......Page 204
Tissue processing and interpretation......Page 206
Management of postoperative defects and postoperative course......Page 207
Further reading......Page 208
Hematoma, ecchymosis, and seroma......Page 209
Dehiscence and epidermolysis (Boxes 17-3 & 17-4, Fig. 17-5)......Page 212
Necrosis (Box 17-5, Fig. 17-6)......Page 213
Infection and mimickers (Table 17-1, Box 17-6, Figs 17-7–17-10)......Page 214
Abnormal scarring and poor wound appearance (Figs 17-11–17-17)......Page 215
Nerve deficits (Fig. 17-18)......Page 217
Further reading......Page 219
Pathophysiology......Page 220
Diagnosis......Page 222
Further reading......Page 229
Laser physics......Page 230
Medical treatment options: vascular laser systems......Page 232
Further reading......Page 242
Clinical overview......Page 246
Surgical approach......Page 249
Vehicle......Page 250
Further reading......Page 253
Index......Page 255

Citation preview

Requisites in

DERMATOLOGY

Dermatologic Surgery Edited by

Allison T Vidimos, RPh, MD, FAAD, FACMS

Chair, Department of Dermatology Cleveland Clinic Foundation Cleveland, OH, USA

Christie T Ammirati, MD, FAAD, FACMS Associate Professor, Department of Dermatology Penn State Milton S. Hershey Medical Center Hershey, PA, USA

Christine Poblete-Lopez, MD, FAAD, FACMS

Associate Staff, Department of Dermatology Cleveland Clinic Foundation Cleveland, OH, USA Series editor

DIRK M ELSTON

Edinburgh London New York Oxford Philadelphia St Louis Sydney Toronto 2009

An imprint of Elsevier Limited © 2009, Elsevier Limited. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of the Publishers. Permissions may be sought directly from Elsevier’s Health Sciences Rights Department, 1600 John F. Kennedy Boulevard, Suite 1800, Philadelphia, PA 191032899, USA: phone: (+1) 215 239 3804; fax: (+1) 215 239 3805; or, e-mail: [email protected]. You may also complete your request on-line via the Elsevier homepage (http://www.elsevier. com), by selecting ‘Support and contact’ and then ‘Copyright and Permission’. First published 2009 ISBN: 978-0-7020-3049-9 British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library Library of Congress Cataloging in Publication Data A catalog record for this book is available from the Library of Congress Notice Neither the Publisher nor the Editors assume any responsibility for any loss or injury and/or damage to persons or property arising out of or related to any use of the material contained in this book. It is the responsibility of the treating practitioner, relying on independent expertise and knowledge of the patient, to determine the best treatment and method of application for the patient. The Publisher

Printed in China

Acknowledgments We would like to thank our mentors and teachers who have taught us the art and science of dermatologic surgery, our residents, fellows and medical students who have given us the privilege and pleasure of teaching them, and our patients who put their trust in us and challenge us to be

better physicians every day. Special thanks go to the the art and photography departments at Cleveland Clinic, especially Joe Pangrace, Bill Garriott, Beth Halasz, and our dermatology department photographer, Flora Williams.

Dermatologic surgery dedications This text is dedicated to my parents Al and Audrey Vidimos, my brothers Scott, David and Dan, my husband Todd Stultz, and daughters Katherine and Kristen for their love, support, encouragement, and inspiration. Allison T Vidimos This text is dedicated to my children Emma and Nicholas and my parents Bob and Bee Travelute, who inspired me to always reach higher, and to my husband Chris, who held the ladder so I could climb. Christie T Ammirati

This text is dedicated to my husband, Seevee, who has given me unconditional love and the support to pursue what I truly enjoy, most evident in this endeavor; to my children, Veto, Samee, and Neo, who are the source of my strength and inspiration; to my parents, who taught me the value of education; to all my mentors, from whom I learned the art of surgical technique; and to all the residents and fellows to whom I’ve tried to teach the importance of this art. Christine Poblete-Lopez

Contributors

Erin J. Allen, md Providence Dermatologic Surgery Portland, OR Christie T. Ammirati, md Associate Professor of Dermatology Department of Dermatology Penn State Milton S. Hershey Medical Center Hershey, PA Philip L. Bailin, md Program Director, Dermatologic Surgery and Cutaneous Oncology Department of Dermatology Cleveland Clinic Foundation Cleveland, OH Ashish C. Bhatia, md Department of Dermatology and Dermatologic Surgery DuPage Medical Group, Naperville, IL Assistant Professor of Clinical Dermatology Department of Dermatology Northwestern University – Feinberg School of Medicine Chicago, IL Elizabeth Magill Billingsley, md Associate Professor of Dermatology Department of Dermatology Penn State Milton S. Hershey Medical Center Hershey, PA Lisa B. Campbell, md Chief of Dermatology and Dermatologic Surgery Geisinger Health System Western Region Geisinger Medical Group State College, PA T. Minsue Chen, md Fellow, Mohs Research in Advanced Dermatologic Surgery Education Mohs and Dermasurgery Unit Department of Dermatology University of Texas, M. D. Anderson Cancer Center Houston, TX

Theresa Dressler Conologue, do Director, Cosmetic Dermatology Service Geisinger Medical Center Danville, PA Daihung Vu do, md Instructor in Dermatology Associate Director of Dermatologic Surgery Department of Dermatology Beth Israel Deaconess Medical Center Boston, MA John Ebner, do Department of Dermatology Cleveland Clinic Foundation Cleveland, OH Gregory J. Fulchiero Jr, md, MSBioEng Dermatologic Surgery and Cutaneous Oncology Department of Dermatology UT Southwestern Medical Center Dallas, TX Christopher Charles Gasbarre, DO Department of Dermatology Cleveland Clinic Foundation Cleveland, OH Lisa M. Grandinetti, md Department of Dermatology Cleveland Clinic Foundation Cleveland, OH Joseph F. Greco, md Clinical Instructor UCLA Division of Dermatology Department of Medicine David Geffen School of Medicine at UCLA Los Angeles, CA

viii

Contributors

Christine M. Hayes, md Associate Professor of Dermatology Department of Dermatology Boston University School of Medicine Boston, MA

Christine Poblete-Lopez, md Associate Program Director Department of Dermatology Cleveland Clinic Foundation Cleveland, OH

Christopher Riddell Jones, md Department of Dermatology Penn State Milton S. Hershey Medical Center Hershey, PA

Matthew R. Ricks, md LtCol, USAF, MC, SFS Chief of Mohs Surgery Wilford Hall Medical Center Lackland AFB, TX

Ken K. Lee, md Director of Dermatologic and Laser Surgery Associate Professor of Dermatology, Surgery, Otolarynogology – Head and Neck Surgery Oregon Health and Science University Portland, OR

Christopher B. Skvarka, md Department of Dermatology Hahnemann Hospital Drexel University College of Medicine Philadelphia, PA

Victor J. Marks, md Department of Dermatology Geisinger Medical Center Danville, PA

Aashish Taneja, md Department of Dermatology Wayne State University Dearborn, MI

Edward V. Maytin, md, PhD Staff, Dermatology Cleveland Clinic Foundation Assistant Professor of Molecular Medicine Cleveland Clinic Lerner College of Medicine of Case Western Reserve University Cleveland, OH

Leonid Benjamin Trost, md Department of Dermatology Cleveland Clinic Foundation Cleveland, OH

Susan Teri McGillis, md Director, Dermasurgery Center Lancaster, PA Jon G. Meine, md Staff, Department of Dermatology, Section of Dermatologic Surgery and Cutaneous Oncology Cleveland Clinic Foundation Cleveland, OH Allison Jo Moosally, md Clinical Associate Staff Department of Dermatology Cleveland Clinic Foundation Cleveland, OH Tri H. Nguyen, md Director of Mohs/Dermatologic Surgery Associate Professor Mohs and Dermasurgery Unit Department of Dermatology University of Texas, M. D. Anderson Cancer Center Houston, TX

Allison T. Vidimos, RPh, md Chair, Dermatology Cleveland Clinic Foundation Cleveland, OH Paula S. Vogel, md Col (Ret), USA, MC Mohs Surgeon Dermatology Associates San Antonio, TX Rungsima Wanitphakdeedecha, md Department of Dermatology Faculty of Medicine Siriraj Hospital Mahidol University Bangkok, Thailand Andrea Willey, md Assistant Clinical Professor Department of Dermatology University of California, Davis Davis, CA Brittany Wilson, md Department of Dermatology Oregon Health and Science University Portland, OR

Contributors

Oliver J. Wisco, do Maj, USAF, MC, FS Department of Dermatology Wilford Hall Medical Center Lackland AFB, TX Justin G. Woodhouse, md University Dermatologists, Inc. South Euclid, OH

Summer R. Youker, md Assistant Professor of Dermatology Saint Louis University St Louis, MO

ix

Also in the series Requisites in

Dermatology Series Editor: Dirk M Elston

Dermatopathology

Dirk M Elston and Tammie Ferringer

Cosmetic Dermatology Murad Alam, Hayes B Gladstone, and Rebecca C Tung

Pediatric Dermatology Howard B Pride, Albert C Yan, and Andrea L Zaenglein

Dermatologic Surgery

Allison T Vidimos, Christie T Ammirati, and Christine Poblete-Lopez

General Dermatology

Kathryn Schwarzenberger, Andrew E Werchniak, and Christine J Ko

Series foreword The Requisites in Dermatology series of textbooks is designed around the principle that learning and retention are best accomplished when the forest is clearly delineated from the trees. Topics are presented with an emphasis on the key points essential for residents and practicing clinicians. Each text is designed to stand alone as a reference or to be used as part of an integrated teaching curriculum. Many gifted physicians

have contributed their time and energy to create the sort of texts we wish we had had during our own training and each of the texts in the series is accompanied by an innovative on-line module. Each on-line module is designed to complement the text, providing lecture material not possible in print format, including video and lectures with voice-over. These books have been a labor of love for all involved. We hope you enjoy them.

Series dedication This series of textbooks is dedicated to my wife Kathy and my children, Carly and Nate. Thank you for your love, support and inspiration. It is also dedicated to the residents and fellows it has been my privilege to teach and to the patients who have taught me so much. Dirk M Elston

Volume preface This text is designed to cover the essentials of dermatologic surgery in a style that is straight forward and easily understood. Each topic is presented as a concise, yet thorough, review, and each chapter is paired with an on-line

lecture. In this manner, the text acts as an over­ view for students learning the surgical aspects of dermatology, a focused study guide for dermatology residents, and a ready reference for those in practice.

Acknowledgments We would like to thank our mentors and teachers who have taught us the art and science of dermatologic surgery, our residents, fellows and medical students who have given us the privilege and pleasure of teaching them, and our patients who put their trust in us and challenge us to be

better physicians every day. Special thanks go to the the art and photography departments at Cleveland Clinic, especially Joe Pangrace, Bill Garriott, Beth Halasz, and our dermatology department photographer, Flora Williams.

Dermatologic surgery dedications This text is dedicated to my parents Al and Audrey Vidimos, my brothers Scott, David and Dan, my husband Todd Stultz, and daughters Katherine and Kristen for their love, support, encouragement, and inspiration. Allison T Vidimos This text is dedicated to my children Emma and Nicholas and my parents Bob and Bee Travelute, who inspired me to always reach higher, and to my husband Chris, who held the ladder so I could climb. Christie T Ammirati

This text is dedicated to my husband, Seevee, who has given me unconditional love and the support to pursue what I truly enjoy, most evident in this endeavor; to my children, Veto, Samee, and Neo, who are the source of my strength and inspiration; to my parents, who taught me the value of education; to all my mentors, from whom I learned the art of surgical technique; and to all the residents and fellows to whom I’ve tried to teach the importance of this art. Christine Poblete-Lopez

Joseph F. Greco and Christopher B. Skvarka

The essentials of dermatologic surgery must be founded on a fundamental and thorough under­ standing of the head and neck anatomy.This ­chapter begins with an outline of important topographic landmarks and cosmetic units before focusing on the musculature, nerve anatomy, vasculature, and lymphatics of the head and neck. Special anato­ mic structures and regions such as the parotid gland and scalp are addressed as well. Emphasis has been placed on the boundaries of anatomic regions and danger zones as well as the spacial relationships among clinically relevent structures.

Topographical landmarks Key Points • The bony and muscular landmarks of the head and neck aid in locating underlying structures.

• The supraorbital, infraorbital, and mental foramina lie on the midpupillary line.

• The masseter muscle aids in locating the facial artery and Stenson’s duct (parotid duct).

• The sternocleidomastoid muscle divides the neck into anterior2 and posterior triangles.

The important topographical landmarks of the head and neck are formed primarily by underlying bones and musculature, but superficial accepted divisions are also made. These landmarks and divisions are important cosmetically and are used in communication by the cutaneous surgeon. The scalp is divided into four areas – frontal, parietal, temporal, and occipital. The frontal scalp extends from the forehead to the vertex and is bordered by the parietal and temporal regions. The occipital scalp is located at the inferior por­ tion of the scalp, and overlies the occipital bone. The forehead meets the frontal scalp and extends down to the eyebrows and glabella. The glabella lies between the eyebrows superior to the nasal root. Vertical furrows (glabellar lines) are accen­ tuated over this region when frowning. The frontal, maxillary, zygomatic, temporal, and mandibular bones all form prominent bony surface markers – the orbital rims, zygomatic

1

Chapter

Surgical anatomy of the head and neck

Table 1-1  The orbital rim

Border

Bones

Superior

Frontal bone

Lateral

Frontal process of zygomatic bone

Inferior

Zygomatic bone laterally and maxillary bone medially

Medial

Frontal bone superiorly and maxilla inferiorly

arch, mastoid process, and mental protuberance. The orbital rim is formed by contributions from the frontal, zygomatic, and maxillary bones (­Table 1-� 1). Of note, the medial canthal ligaments are easily palpated at the medial rim. Immediately above the superior orbital rim lies the first of the three major foramina that can be found along a vertical, midpupillary line imag­ ined approximately 2.5 cm lateral to the midline (Fig. 1-1). The supraorbital, along with the ­infraorbital and mental foramina will be discussed further in the sensory innervation of the head and neck section. The prominence of the cheek or “cheekbone” is formed by the malar eminence of the ­zygoma­tic bone. The buccal fat pad fills the area beneath this eminence and gives fullness to the cheek. The zygomatic arch extends from the malar eminence towards the external acoustic meatus and is formed by the temporal process of the zygomatic bone and the zygomatic process of the temporal bone. The zygomatic arch also divides the temporal fossa superiorly from the infratemporal fossa inferiorly. The temple is a well defined danger zone where the temporal branch of the facial nerve and the superficial temporal artery and vein lie vulnerable to injury (Table 1-� 2). The danger zones and areas of susceptibility to injury are characterized later in this chapter. The auricle is the entire visible portion of the external ear with many named processes (Fig. 1-2). The rim of the auricle is known as the helix, which runs with a paired prominence, the anti­helix. The antihelix runs anterior to the helix and divides



Dermatologic Surgery

Parietal bone

Frontal bone

Midpupillary line

Supraorbital foramen 2.5cm

Temporal bone

Nasal bone

Infraorbital foramen Mastoid process Zygomatic arch

Maxillary bone

Ramus of mandible Angle of mandible Body of mandible Mental foramen Figure 1-1  Bony landmarks of the skull and foramina

into two crura. Between these crura, the named triangular fossa appears. The curved depression between the helix and antihelix is referred to as the scapha. Inferior to the antihelix lies a deep cavity known as the concha. Anterior to the con­ cha, the tragus arises as an eminence in front of the external acoustic meatus. ­Opposite from the tragus (separated by the intertragic notch) is a small tubercle called the antitragus. Behind the ear lies the mastoid process of the temporal bone. It is a bony prominence that, after adolescence, protects the facial nerve as it exits the stylomastoid foramen.  Anterior to the ear lies the condyle of the mandibular ramus, which can be palpated as the mouth opens and closes. The angle of the jaw and prominence of the chin are formed by the mandibular angle and mental pro­ tuberance, respectively. The masseter muscle attaches to the ­zygomatic arch and inserts on the ramus of the mandible. It can be palpated most easily while the teeth

Table 1-2  Borders of the temple

Border Inferior

Zygomatic arch

Anterior

Tail of the eyebrow

Superior

Coronal suture line

Posterior

Temporal hairline

are clenched. The facial artery may be found and palpated near the antero-inferior border of the masseter. The nasal bones, alar cartilages, and anterior nasal spine of the maxilla form the palpable bor­ ders of the nose. The nasal bones form the supe­ rior root of the nose and the anterior nasal spine can be palpated at the root of the columella. The labial area is bordered by the nose, medial cheek, and mental chin. This area is separated from the cheek by the melolabial crease. The upper lip

ah at atn c cav cym ea h

antihelix antitragus auriculotemporal nerve conchal bowl cavum of conchal bowl cymba of conchal bowl external auditory meatus helix

hr in l sf sta stv tf tr

Chapter

Surgical anatomy of the head and neck

1

helical root/crus intertragic notch lobule scaphoid fossa superficial temporal artery superficial temporal vein triangular fossa tragus

Figure 1-2  Anatomy of the ear, superficial temporal artery, and auriculotemporal nerve

is divided in half by the philtrum. The philtrum is a central linear depression bordered by two verti­ cal columns extending from the columella to the vermillion border of the upper lip. At this inferior border, the columns help to create a contoured double curve, resembling Cupid’s bow. Continuing inferiorly, the most important ­superficial landmark of the neck is the sternoclei­ domastoid muscle. When contracted, it is easily palpated. See Table 1-� 3 for a discussion of the

sternocleidomastoid muscle. This muscle divides the neck into anterior and posterior triangles (see Table 1-� 4 for information on the anterior ­triangle and Table 1-15 for the posterior triangle). The ­anterior triangle can be subdivided into the muscu­ lar, carotid, digastric, and submental triangles. Of note, the spinal accessory nerve is suscep­ tible to injury in the posterior triangle. Injury ­results in paralysis of the sternocleidomastoid and trapezius muscles.





Dermatologic Surgery Table 1-3  The sternocleidomastoid muscle

Table 1-4  The anterior triangle

Origin

Boundary

Two heads – medial head attaches to the sternum; lateral head attaches to the medial third of the clavicle

Insertion

Mastoid process of the temporal bone and lateral portion of the superior nuchal line

Innervation

Accessory nerve (cranial nerve XI)

Action

Acting alone, a single sternocleidomastoid muscle turns the head towards the ipsilateral shoulder in an upward glance; in tandem, both sternocleidomastoid muscles draw the head forward

Comments

The two originating heads of each sternocleidomastoid muscle form a depression referred to as the lesser supraclavicular fossa; torticollis is due to the permanent contracture of the sternocleidomastoid

Parotid gland and duct Key Points • The parotid glands are the largest paired salivary glands.

• The facial nerve pierces the parotid gland soon after leaving the stylomastoid foramen.

• The parotid duct may be palpated as it courses over the masseter muscle.

The parotid gland is an anatomic landmark deserving of special consideration. It is a ­triangularshaped salivary gland nestled anterior to the auri­ cle within the borders of the zygomatic arch and mandible (Fig. 1-� 3, Table 1-� 5). It is anchored into place by a fibrous fascial capsule contiguous with the deep facia of the neck. The substance of the gland houses and protects the facial nerve as it branches into a superior temporofacial and infe­ rior cervicofacial division. The five well known branches of the facial nerve originate from these divisions prior to exiting the different poles of the parotid gland (Table 1-� 6). The parotid duct emerges from the gland at its upper anterior pole and courses over the mas­ seter muscle and buccal fatpad (Fig. 1-� 4). Here it turns medially to pierce the buccinator muscle and ­ enters the oral mucosa opposite the second upper molar (Fig. 1-� 5). The duct runs approxi­ mately one fingerbreadth inferior to the zygomatic arch, between the transverse facial artery and buccal branch of the facial nerve. With the jaw clenched, the parotid duct may be palpated as a firm cord along the middle third of a line drawn from the earlobe to a point between the oral com­ missure and the nasal ala as it runs atop the mas­ seter. The duct is most vulnerable in this ­location

Anterior

Median line of neck

Posterior

Anterior border of sternocleidomastoid muscle

Superior (base)

Inferior border of mandible

Roof

Skin, SMAS, platysma, and deep fascia of neck

Floor

Inferior and middle pharyngeal constric­ tors; thyrohyoid and hyoglossus muscles (carotid triangle); mylo­hyoid and hyoglossus muscles (digastric triangle), mylohyoid muscle (submental triangle)

during surgical procedures. ­Transection will result in extravasation of a clear watery fluid. If left ­unrepaired, an external fistula may develop. Thin watery saliva and thicker mucous of the parotid gland mediated by sympathetic and para­ sympathetic fibers respectively. Cutaneous sen­ sory innervation over the parotid gland is carried by the auriculotemporal nerve. Vascular supply and lymphatic drainage of the parotid area are des­cribed elsewhere in this chapter.

Contour lines and cosmetic units Key Points • Contour lines separate the face into anatomic subunits.

• Regional variablility in skin structure impacts the dermatologic surgeon’s choice of repair.

• Free margins are a type of contour line.

Contour lines are the natural lines of demarcation that divide the face into several cosmetic units, such as the forehead and nose (Table 1-� 7). Gen­ erally speaking, the skin texture and color is con­ sistent within each cosmetic unit and may vary considerably among them. This is due in part to the differences in the density of sebaceous glands, terminal hair follicles, thickness and elasticity of the skin. The highly thick and sebaceous skin of the nose, for example, lies in stark contrast to the neighboring thin and highly lax skin of the eyelid. Defects in one cosmetic unit are therefore best repaired with skin of that same cosmetic unit. The dermatologic surgeon must consider this regional variability during reconstructive surgery. Surgical incisions may be placed so that the final scar lies along or parallel to contour lines. Incisions that violate this principle by crossing the demarca­ tion lines may distort anatomic units and result in highly perceptible scarring.

bfp fa fv ma orb oc

buccal fat pad facial artery facial vein masseter muscle orbicularis oculi

orb or pd scm sta tfa zm

Chapter

Surgical anatomy of the head and neck

1

orbicularis oris parotid duct sternocleidomastoid muscle superficial temporal artery transverse facial arter zygomaticus major

Figure 1-3  Anatomy of the parotid gland and related structures

Table 1-5  Borders of the parotid gland

Superior

Posterior two thirds of zygomatic arch

Posterior

Posterior border of mandibular ramus

Inferior

Angle of mandible

Anterior

Highly variable

Floor

Posterior half of masseter

Roof

Integument, parotid fascia

Free margins are a unique type of anatomic unit characterized by skin edges that are ­separated from neighboring tissue by an open cavity. Exam­ ples include the lips, eyelids, helical rims, nasal alae, and columella. Defects and repairs in close proximity to free margins may have tension forces that push or pull on the margin. Distortion may result in both aesthetic and functional impairment

Table 1-6  Facial nerve branches and the parotid gland

Facial nerve branch

Exiting pole of the parotid

Temporal (temporofacial division)

Superior

Zygomatic (temporofacial division)

Anterosuperior

Buccal (temporofacial division)

Anterior

Marginal mandibular (cervicofacial division)

Anteroinferior

Cervical (cervicofacial division)

Inferior

such as eversion of the eyelid (ectropion) or lip (eclabion). Cosmetic units may be further divided into subunits for anatomic classification. This permits more precise localization of cutaneous neoplasms especially in patients presenting with numerous lesions.





Dermatologic Surgery

b bfp bz fa fv orb oc

buccal branch (VII) buccal fat pad buccal/zygomatic nerve anastomoses facial artery facial vein orbicularis oculi

pd pg t tfa z zm

parotid duct parotid gland temporal branch (VII) transverse facial artery zygomatic branch (VII) zygomaticus major

Figure 1-4  Anatomy of the parotid duct and facial nerve

The superficial musculoaponeurotic system (SMAS) Key Points • The fibromuscular layer is composed of the

muscles of facial expression and enveloping fascia.

• Muscular contraction is transmitted evenly to the skin and adjacent muscles via this system.

• The SMAS permits complex facial movements and contributes to the symmetry of the face.

• It provides an anatomic plane for dissection and protection to neurovascular structures.

• It acts a barrier to infection.

The superficial musculoaponeurotic system (SMAS) lies just deep to the subcutaneous fat and contains two layers of fascia that split to envelop the muscles of facial expression. The breadth of the SMAS is described in Table 1-� 8. In addition to these musculofascial connections, the SMAS bonds to the skin via fibrous strands. Collectively, this system augments and harmonizes facial movements, while acting as a screen to prevent the spread of infection from superficial to deep regions (Fig. 1-� 6). Knowledge of the SMAS aids the cutaneous surgeon in predicting the location of major neuro­ vascular structures. Arteries and sensory nerves of the face are found within the subcutaneous fat or

an b bfp dao fa

fv m pd pg

facial nerve anastomoses buccinator muscle buccal fat pad depressor anguli oris facial artery

Chapter

Surgical anatomy of the head and neck

1

facial vein masseter muscle parotid duct parotid gland

* parotid duct piercing buccinator muscle * marginal mandibular nerve traveling with facial artery Figure 1-5  Parotid duct as it pierces the buccinator muscle

Table 1-7  Cosmetic units and contour lines of the face

Contour line

Cosmetic unit

  Nasolabial fold

�

  Nasofacial sulcus

�

  Mentolabial crease

�

  Preauricular sulcus

�

  Eyelid margins

�

  Philtral columns/crest

�

  Alar contours

�

� � � � � � �

  Vermillion border

�

  Eyebrows

�

  Hairline

�

  Forehead   Nose   Cheek   Eye   Lip   Chin   Ear

at the SMAS–subcutaneous fat junction. All mo­ tor nerves course below the SMAS. A sub-SMAS dissecting plane is attractive owing to its ­relatively avascular nature. However, the risk to the motor nerves precludes use of the sub-SMAS plane in most locations. The subcutaneous fat superficial to the SMAS is therefore the ideal dissecting plane. An exception occurs over the pre-parotid cheek where the motor fibers of the facial nerve lie protected within the substance of the parotid gland. Of note, the temporal branch of the facial nerve lies just deep to the thin superficial tem­ poral ­fascia on the medial temple. On the lateral temple, the auriculotemporal nerve and ­superficial temporal vessels are located in the subcutaneous fat above the superficial temporal fascia.





Dermatologic Surgery Table 1-8  SMAS relationships

Skin tension lines of the face (STLs)

Region

SMAS attachment site

Posterior (occiput)

Inserts onto the mastoid process and fascia of sternocleidomastoid muscle; envelops occipitalis

Key Points

Superior (scalp)

Forms the galea aponeurotica to unite the occipitofrontalis muscle; lacks muscle fibers

• Dynamic and relaxed STLs lie perpendicular to

Forehead

Envelops frontalis muscle

• Lines become more visible and deeper with age

Temporal scalp

Continuous with the superficial temporal fascia

Zygomatic arch

SMAS is discontinuous above and below this insertion point; the actions of the upper and lower muscles of facial expression are functionally separated here

Cheek

Deep leaflet of the SMAS fuses with the parotid and masseteric fascia; envelops muscles of facial expression

Anterior (neck)

Continuous with the superficial cervical fascia; envelops platysma

Midfacial region

Devoid in areas; not well delineated

• Skin tension lines are the distinctive furrowed or wrinkled lines on the face.

the action of underlying muscle fibers.

and sun damage.

• Knowledge of the skin tension lines is required

for successful cutaneous surgery and proper use of cosmetic injectables.

Tension, created by the intermittent contraction of the muscles of facial expression, is transmit­ ted by fibrous strands from the SMAS to the skin. The elasticity of the skin with youth opposes this tension and maintains a smooth appearance. With age, the elastic fibers decrease in their ability to resist tension, and collagen fibers elongate, decrease in size, and become cross-linked. With damaged collagen and elastin, linear wrinkles form along the attachments of the SMAS to the skin.

*

* SMAS fibers connecting the underlying temporalis muscle to the skin Figure 1-6  Superficial musculoaponeurotic system (SMAS)

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Surgical anatomy of the head and neck

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Figure 1-7  Skin tension lines

Generally these wrinkles, termed skin tension lines (STLs), run perpendicular to the underlying muscle fibers (Fig. 1-� 7). For example, the STLs of the forehead are horizontal because the frontalis muscle contracts vertically. The skin tension lines of the lateral periocular skin (crow’s feet) radiate away from the lateral canthus, as the fibers of the orbicularis oculi circumferentially wrap from the superior to inferior eyelid. The horizontal wrinkles of the upper eyelid, which at first seem to contra­ dict this principle, lie perpendicular to the axis of the underlying levator palpebrae superioris. Surgical planning must include a thorough knowledge of the STLs. The reconstruction of sur­ gical defects should be designed to minimize per­ ceptible scarring. One such way is to align the long axis of a repair within or parallel to the STLs. This places the scar under the least amount of tension, allowing the scar to fall within a natural wrinkle. Wounds close more easily in this orientation, as the skin is approximately three times more disten­ sible perpendicular to the STLs than parallel. In elderly patients with severe sun damage, the relaxed STLs will be obvious to any observer. However, certain techniques may be utilized to accentuate these lines where the static wrinkles

may not be so noticeable. Furrows can be accen­ tuated by asking patients to perform exaggerated facial expressions, such as smiling, frowning, puckering lips, or whistling. Active manipulation of the skin by a gentle pinch or massage may also reproduce the natural folds and tension lines. STLs may be softened or eliminated by cos­ metic injectable treatments. Injectable botulinum toxin targets the dynamic STLs and moderately fine relaxed STLs by blunting the actions of the underlying musculature. However, deeper ­relaxed STLs, accentuated by the gravitational pull of sun-damaged skin, are better treated by injectable fillers, which replace volume loss.

The facial nerve and muscles of facial expression Key Points • The muscles of facial expression develop from the second embryonic arch.

• They contribute to the relaxed skin tension lines of the face.

• They are innervated by the seventh cranial nerve – the facial nerve.



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Dermatologic Surgery

Temporal branches

Zygomatic arch Superficial temporal artery

Zygomatic branch

Stylomastoid foramen

Facial nerve (CN-VII): main trunk

Parotid duct Buccal branches

Temporofacial division of VII Cervicofacial division of VII

Facial artery Masseter muscle Marginal mandibular branches

Parotid gland Cervical branch

Figure 1-8  Illustration of the facial nerve

The facial nerve, or cranial nerve VII, exits the skull at the stylomastoid foramen and proceeds to innervate the muscles of facial expression (Fig. 1-� 8). Immediately after exiting the foramen, the posterior auricular branch breaks off the main trunk to innervate the occipitalis and ­postauricular muscles. The remainder of the nerve pierces the parotid gland and departs as five branches – temporal, zygomatic, buccal, marginal mandi­ bular, and cervical (Fig. 1-� 9). Each branch of the nerve is discussed separately. Table 1-� 9 highlights the muscles innervated by each branch. During surgical procedures injury to a single branch of the facial nerve is more likely to occur than injury to the main trunk. Conflicting ­reports exist on the most common branch injured, as

the temporal, buccal, and marginal mandibular branches have all been implicated in different series. Permanent injury to one of the branches of the facial nerve is reported as 0.4–2.6%, with equal rates for subcutaneous and sub-SMAS ­procedures. The temporal branch is particularly vulnerable to damage on the lateral face after exiting the ­superior pole of the parotid gland (Table 1-10, Fig. 1-10). This branch runs deep to the skin, subcu­ taneous tissue and a thin layer of fascia along its course to the frontails and orbicularis oculi mus­ cles. To prevent damage to this nerve, the surgeon should only dissect down to the superficial fat in this area. Table 1-10 highlights other areas where the facial nerve is susceptible to injury.

b bz c fa

buccal branch buccal/zygomatic anastomoses cervical branch facial artery

dotted line dotted circle

mm t z

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Surgical anatomy of the head and neck

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marginal mandibular branch temporal branch zygomatic branch

damaged nerves anterior to it likely result in full recovery while damaged nerves posterior to it likely result in permanent paralysis danger zone for fa and mm

Figure 1-9  Anatomy of the facial nerve

The zygomatic branch exits the anterosuperior border of the parotid gland and divides into ­upper and lower rami (see Figs 1-4 & 1-9). Branches of the lower ramus lie on the parotid duct. Injury to the zygomatic branch results in difficult clos­ ing the ipsilateral lower eyelid and can affect the nasal muscles and lip ­elevators. The buccal branch exits the anterior border of the parotid gland before coursing anteriorly over the masseter muscle and buccal fat pad. This ­division runs parallel to the parotid duct prior to delivering extensive rami to the mid-facial region (see Figs 1-4 & 1-9). Damage to this branch may lead to the accumulation of food between the teeth and buccal mucosa while chewing, as well as drooling, impaired lip pursing, and impaired smiling. Injury to the zygomatic or buccal branch­ es is often temporary because of the high degree of anastamoses between the two branches. Some 70–90% of ­patients have these anastomoses.

The marginal mandibular branch exits the infe­ rior pole of the parotid gland and travels along the lower angle of the mandible anterior to the facial artery (see Fig. 1-� 9). Ramification occurs distally, near the muscles of the lower lip. This renders the nerve vulnerable in its more proximal subplatys­ mal location near the anterior insertion point of the masseter muscle on the mandible. With injury to this nerve, the lower lip becomes impaired in its downward movement, which can lead to an asymmetric smile. The cervical branch of the facial nerve exits the inferior pole of the parotid gland and ­descends toward the submandibular triangle before ram­ ifying extensively to innervate the platysma (see Fig. 1-� 9). Injury to this branch rarely causes ­noticeable damage. The extensive anastomotic network of the facial nerve, particularly via the zygomatic and buccal branches, may be predicted by dropping

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Dermatologic Surgery Table 1-9  Muscles innervated by the facial nerve

Table 1-10  Areas of the facial nerve susceptible to injury

Branch of facial nerve

Muscle innervated by branch

Branch of facial nerve

Danger zone description

Temporal

Frontalis

Facial nerve trunk as it exits the stylomastoid foramen

Behind the earlobe in children, the facial nerve trunk is vulnerable to injury. In adults, the trunk is protected by the mastoid process

Auricular

Facial nerve in the parotid gland

Vulnerable to injury if the procedure breaches the fascia of the parotid gland

Orbicularis oculi (lower portion)

Temporal branch 

Located between an imaginary line drawn between the earlobe and the lateral eyebrow and a second line drawn between the earlobe and the most superior forehead crease. It lies in its most superficial position as it crosses the zygomatic arch. The facial nerve likely has multiple rami at this point

Buccal branch

Lying superficial to the masseter muscle, but deep to SMAS, this section is vulnerable at its branching points, 2 cm anterior to its exit of the parotid gland and under the modiolus (see below)

Marginal mandibular

This branch lies just below the fascia of the SMAS anterior to the facial vein and artery as it crosses the inferior edge of the mandible near the insertion point of the masseter

Corrugator supercilii Orbicularis oculi (upper portion) Zygomatic

Nasalis (alar portion) Procerus Buccinator Buccal

Buccinator Depressor septi nasi Nasalis (transverse portion) Zygomaticus major and minor Levator labii superioris Levator anguli oris Risorius Orbicularis oris (upper portion)

Marginal mandibular

Orbicularis oris (lower portion) Depressor anguli oris Depressor labii inferioris Mentalis

Cervical

Platysma

nerve (Fig. 1-15). See ­ Boxes 1-1 through 1-3 for the other functions of the facial nerve.

Sensory innervation of the head and neck The trigeminal nerve

an imaginary vertical line down from the lat­ eral canthus. Branches anterior to this line have ­extensive anastomoses, and injured nerves in this “safe zone” will likely recover. Damage posterior to this line, however, often results in permanent paralysis of the target musculature. Table 1-11 discusses each muscle of facial ­expression separately. See Figures 1-11 through 1-13 for the muscular anatomy of the face. With the exception of the buccinator, the muscles of ­ facial expression receive motor innervation from their deep surface and thus protect their ­terminal branches (Fig. 1-14). Of note, the ­levator ­palpebrae superioris muscle elevates the upper ­eyelid under the direction of the ­ oculomotor nerve ­ (cranial nerve III) rather than the facial

Key Points • The trigeminal nerve, cranial nerve V, is the largest of the 12 cranial nerves.

• The three main branches are the ophthalmic (V1), maxillary (V2), and mandibular (V3).

• The trigeminal nerve provides the primary sensory innervation to the face.

• It also provides motor innervation to the muscles of mastication.

• Effective anesthesia via nerve blocks can be placed by the cutaneous surgeon with an understanding of the anatomy of the trigeminal nerve.

The trigeminal nerve, the largest of the cranial nerves, is the fundamental provider of sensory ­innervation to the face, supplying structures de­ rived from the first branchial arch. Three branches

Chapter

Surgical anatomy of the head and neck

1

The danger zone is predicted by drawing an imaginary line between the earlobe and the lateral eyebrow and a second line drawn between the earlobe and the most superior forehead crease. The temporal branch of the facial nerve is vulnerable to injury as it courses over the zygomatic arch within this zone. Figure 1-10  The facial nerve: danger zone Table 1-11  The muscles of facial expression

Muscle

Contraction

Origin

Insertion

Comments

Frontalis

Raises eyebrows and wrinkles forehead; allows skin to slide over scalp

Galea aponeurosis

Fibers intertwine with procerus, orbicularis oculi, and corrugator supercilii muscles

Part of the epicranius; the fibers of the frontalis are vertically oriented. The horizontal forehead skin tension lines are created by this muscle. If denervated, the eyebrow droops and skin tension lines relax on the damaged side

Corrugator supercilii

Draws eyebrows medially and downward

Nasal bone

Skin above middle eyebrow

Creates the vertical glabellar frown lines with the medial portion of the orbicularis oculi and depressor supercilii

Orbicularis oculi

Eyelid closure and upper eyelid depression; aids in tear excretion

Medial canthal tendon and nasal portion of frontal bone

Eyelid skin and surrounding musculature; lateral portion of orbicularis oculi is uninterrupted at the lateral canthus

Contraction forms folds that radiate from the lateral canthus (“crow’s feet”)

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Dermatologic Surgery Table 1-11  The muscles of facial expression—cont’d

Muscle

Contraction

Origin

Insertion

Comments

Nasalis

Compresses and widens nasal aperture (“flares nostrils”) with deep inspiration

Maxilla lateral to nasal notch

Nasal aponeurosis

Major muscle of the nose

Levator labii superioris alaque nasi

Elevates ala and upper lip

Superiorly at maxilla

Alar cartilage and upper lip

Procerus

Draws down medial angle of eyebrow and produces horizontal wrinkles over nasal bridge

Nasal bones and cartilage

Skin between eyebrows

Temporary paralysis of this muscle helps to reduce “bunny lines”; continuous with frontalis muscle

Buccinator

Compresses cheek against teeth

Maxilla and mandible

Submucosa of cheek and orbicularis oris

Muscular wall of cheek; if denervated, food accumulates between teeth and cheek while chewing. Pierced by parotid duct as it enters the mouth; receives motor innervation from its superficial surface

Zygomaticus major

Upper lip elevator; draws angle of mouth upward

Zygomatic bone

Upper lip, angle of mouth

Important for smiling and laughing

Zygomaticus minor

Upper lip elevator

Zygomatic bone

Orbicularis oris muscle

Deepens nasolabial sulcus during sadness

Levator labii superioris

Elevates and everts upper lip

Maxilla and zygomatic bone

Upper lip

Provides a protective roof over the infraorbital foramen

Levator anguli oris

Raises angle of mouth

Maxilla

Angle of mouth

Contributes to depth of nasolabial furrow

Risorius

Draws corner of mouth laterally

Zygomatic arch and parotid fascia

Angle of mouth/ modiolus

Important for the smile

Orbicularis oris

Sphincter muscle of lips for closing, pursing, protruding, or inflecting (prevents lip protrusion)

Maxilla, mandible, and modiolus (1 cm lateral to corner of lips; fibers from orbicularis oris, lip elevators, and lip depressors converge to form a compact, mobile, fibromuscular mass called the modiolus)

Lips and vermillion border

Modiolus contributes to cheek dimples

Depressor anguli oris

Pulls angle of mouth downward and laterally

Mandible

Angle of mouth

Depressor labii inferioris

Draws lower lips downward as to convey impatience, and may assist with eversion

Mandible and mental foramen

Skin and mucosa of lower lip

Contributes to expression of irony, sorrow, melancholy, and doubt

Mentalis

Raises skin of chin and everts lower lip to express doubt or to pout

Mandible

Skin of chin

A wide space between the two mentalis muscles can create a chin dimple

Platysma

Depresses and wrinkles skin of lower face and neck

Mandible

Skin of neck and chest

Most superficial muscle of neck; overlies facial artery and vein, as well as marginal mandibular and cervical branches of facial nerve

Anterior auricular

Chapter

Surgical anatomy of the head and neck

1

Superior auricular

Frontal belly of occipitofrontalis

Orbicularis oculi Corrugator supercilii Procerus Nasalis Levator labii superioris alaeque nasi Levator labii superioris Zygomaticus minor Occipital belly of occipitofrontalis

Zygomaticus major Modiolus Orbicularis oris Depressor labii inferioris Mentalis

Posterior auricular

Depressor anguli oris Risorius Buccinator Platysma

Figure 1-11  Muscles of facial expression

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Dermatologic Surgery

an fa fv lao lls orb z zma

levator labii superioris alequae nasi (alar & labial) facial artery facial vein levator anguli oris levator labii superioris orbicularis oculi zygomaticus minor zygomaticus major

Figure 1-12  The cheek: anatomy of the infraorbital muscles

of the trigeminal nerve, the ophthalmic (V1), maxillary (V2), and mandibular (V3), carry sensa­ tion from distinct regions of the face (Fig. 1-16). The regions are located anterior to an angled coronal plane located at the vertex of the skull. Each main branch divides into smaller cutaneous branches either before or after emerging from the skull via bony foramina (the significant branches are listed in Table 1-12). The ophthalmic nerve (V1) is the smallest and uppermost division, and further subdivides into the nasociliary, frontal, and lacrimal nerves. The nasociliary nerve is the progenitor to the exter­ nal nasal branch of the anterior ethmoidal nerve

(which innervates the tip of the nose) and the ciliary nerve (which innervates the cornea). Her­ petic invasion of the ophthalmic division present­ ing with blistering on the nasal tip (Hutchinson’s sign) should alert the doctor to potential corneal involvement. Zoster involvement of the external nasal nerve in one series indicated a 76% chance of ocular involvement – double the chance if no lesions were present at the nasal tip. The frontal branch of the ophthalmic nerve gives rise to the supratrochlear and supraorbital nerves (Fig. 1-17). The supratrochlear nerve is the smaller of the two branches and runs 1 cm lateral to the midline, lying in the supratrochlear

dao dli lao lls m oo r zm

depressor anguli inferioris depressor labii inferioris levator anguli oris levator labii superioris modiolus orbicularis oris risorius zygomaticus major

Figure 1-13  Modiolus, elevators, and depressors

notch of the orbital rim. The supraorbital nerve lies 2.5 cm lateral to the midline and exits via the supraorbital foramen. It is the largest extracranial branch of the ophthalmic nerve. Both branches of the frontal nerve initially run deep to the frontalis muscle. At the mid-forehead, the medial branch of the supraorbital nerve penetrates the frontalis to run superficial to it. The maxillary branch (V2) divides into the infraorbital, zygomaticofacial, and zygomatico­ temporal branches. Of note, the infraorbital nerve exits via the infraorbital foramen of the maxilla (discussed below) and lies between the superior heads of the levator labii superioris and levator anguli oris (Fig. 1-18). The infraorbital division innervates the medial cheek, upper lip, lower eye­ lid, lateral portion of the nose, and ­nasal ala. Two divisions (ophthalmic [V1] and maxil­ lary [V2]) of the trigeminal nerve provide sensory fibers to the nose (Table 1-13). In the ­trigeminal trophic syndrome, injury to the maxillary division

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Surgical anatomy of the head and neck

1

(V2) results in a characteristic anesthetic ­ lceration of the nasal ala or alar crease. This der­ u matomal insult of the trigeminal nerve may occur after surgical damage to the gasserian ganglion or during postencephalitic states. The nasal tip is spared in this syndrome, as it is innervated by the ophthalmic division (V1). The mandibular branch (V3) is the largest division of the trigeminal nerve. In addition to the sensory functions listed in Table 1-14, it also provides motor fibers to the muscles of masti­ cation (Box 1-� 4). Its main branches include the ­auri­culotemporal, buccal, and inferior alveolar nerves. The auriculotemporal nerve emerges on the face anterior to the tragus and crosses the root of the zygoma to accompany the superfi­ cial temporal artery and vein to the scalp (see 2). The ­buccal nerve runs deep to the pa­ Fig. 1-� rotid gland where it divides into many rami to innervate the skin over the buccinator muscle. The terminal division of the inferior alveolar branch is the mental nerve, which exits to the skin at the mental foramen of the mandible (Fig. 1-19). See Table 1-14 for the cutaneous areas innervated by the branches of all three divisions mentioned. The trigeminal nerve also supplies postgangli­ onic parasympathetic fibers to the lacrimal and parotid glands. Frey’s syndrome, also known as auriculotemporal syndrome, is characterized by pain, hyperhidrosis, and vasodilatation of the cheek when eating (gustatory sweating). This syn­ drome usually occurs after parotid gland surgery with injury to the auriculotemporal nerve. Para­ sympathetic fibers of the auriculotemporal nerve, normally carrying salivary stimuli, incorrectly reinnervate the sweat glands and blood vessels of the cheek. Subsequent gustatory stimuli precipi­ tate the above clinical features. The exit points, or bony foramina, of the ­supraorbital, infraorbital, and mental nerves are found in a vertically oriented, midpupillary line, 2.5 cm lateral to the midline. This vertical line exists because of the predetermined embryol­ ogy of each branch. The supraorbital foramen lies slightly superior to the superior orbital rim. The infraorbital foramen lies 1 cm inferior to the infe­ rior orbital rim along the backslope of the maxil­ lary bone. The mental foramen is located on the lateral surface of the mandible toward the inferior edge of the ramus in the same midpupillary line as the above. Know­ledge of these foramina ­allows the clinician to place anesthesia for ­ effective nerve blocks.

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Dermatologic Surgery

Shows the undersurface of the orbicularis oculi receiving terminal nerve fibers of the zygomatic branch of the facial nerve. Figure 1-14  Orbicularis oculi muscle and the zygomatic branch of the facial nerve

The supraorbital and supratrochlear nerve block can be achieved with anesthetic placed slightly superior to the superior orbital rim, 0.5–2.5 cm lateral to the midline. Anesthetic should be infiltrated deeply as both of these nerves lie underneath the frontalis and corruga­ tor ­ supercilii muscles at this location. Blocking the nerves will provide adequate anesthesia to the ipsilateral forehead and frontal scalp. Care should be taken to avoid intraneural injection for all nerve blocks. Severe pain on injection reported by the patient may indicate an intraneural loca­ tion. This can be corrected by slightly retracting the needle.

Intraoral and percutaneous approaches can be used for the infraorbital nerve block. For the intraoral route, the needle is inserted into the superior labial sulcus with the surgeon’s thumb and index finger grasping the upper lip. The needle is aimed toward the surgeon’s fourth finger overlying the infraorbital foramen (1 cm below the infraorbital rim). Some 1.0–1.5 mL of anesthetic can be injected in this location. The intraoral block offers less pain to the ­patient than the percutaneous route, and allows the needle to enter the tissue in the same plane as the ­ infraorbital nerve. For the percutaneous ­approach, the needle is aimed deeply toward

aa angular artery dna dorsal nasal artery mcl medial canthal ligament

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Surgical anatomy of the head and neck

1

soa supraorbital artery sof supraorbital foramen son supraorbital nerve

Figure 1-15  Levator palpebrae superioris (LPS)

B ox 1 - 1

B ox 1 - 2

Other muscles innervated by branches of the facial nerve

Areas innervated by sensory fibers of the facial nerve

• Stapedius

• External auditory meatus

• Posterior belly of the digastric

• Soft palate

• Stylohyoid

• Pharynx • Taste sensation to the anterior two thirds of the tongue via the chorda tympani branch

B ox 1 - 3

Glands innervated by the facial nerve with parasympathetic fibers • Submaxillary • Submandibular • Lacrimal

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Dermatologic Surgery

From ophthalmic division of trigeminal nerve [V1]

Medial branches of dorsal rami of cervical spinal nerves Greater occipital nerve (C2)

Supraorbital nerve Supratrochlear nerve

Third occipital nerve (C3)

Infratrochlear nerve

From fourth, fifth, sixth, seventh and eighth cervical nerves

External nasal nerve

Branches from cervical plexus Lesser occipital nerve (C2,3)

From maxillary division of trigeminal nerve [V2] Infraorbital nerve Zygomaticofacial nerve Zygomaticotemporal nerves

Great auricular nerve (C2,3) Transverse cervical nerve (C2,3)

Marginal mandibular branch of facial nerve From mandibular division of trigeminal nerve [V3] Mental nerve

Supraclavicular nerves (C3,4)

Buccal nerve Auriculotemporal nerve

Figure 1-16  Trigeminal nerve

Table 1-12  Divisions and branches of the trigeminal nerve

Major branch of trigeminal nerve

Main cutaneous sensory branches

Ophthalmic (V1)

Nasociliary Frontal Lacrimal

Maxillary (V2)

Infraorbital Zygomaticofacial Zygomaticotemporal

Mandibular (V3)

Auriculotemporal Buccal Inferior alveolar

the same foramen through the skin of the cheek. The anesthetic is injected slightly superficial to the ­foramen. This block will provide anesthesia to the upper lip and areas summarized in Table 1-14. The mental block can also be performed ­using intraoral and percutaneous approaches. For the intraoral approach, the needle is advanced in the inferior labial sulcus between the lower first and second premolars towards the fourth ­finger resting on the mental foramen. During this ­insertion, the surgeon’s thumb and index finger grasp the lower lip. Some 0.5–1 mL of anesthetic is ­ required for the mental block, producing ­anesthesia of the ipsilateral chin and lower lip.

aa av dna fro mcl

angular artery angular vein dorsal nasal artery frontalis medial canthal ligament

pro soa son sta stn

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Surgical anatomy of the head and neck

1

procerus supraorbital artery (red) supraorbital nerve (green) supratrochlear artery supratrochlear nerve (yellow)

Figure 1-17  Medial forehead: supraorbital and supratrochlear neurovascular structures

The cervical nerves and the posterior triangle of the neck Key Points • Peripheral nerves of the cervical plexus include

the great auricular, lesser occipital, transverse cervical, and supraclavicular nerve. • A superficial neural-rich zone may be identified within the posterior triangle. Nerves lying within this zone are susceptible to injury during minor surgical procedures. • These nerves are responsible for the sensory innervation of the neck, posterior scalp, a portion of the ear, and skin over the clavicle.

The posterior triangle of the neck has definable boundaries and contains critical motor and sen­ sory nerves (Table 1-15). Cutaneous branches of the cervical plexus, along with the spinal acces­ sory nerve, course through the posterior triangle of the neck in a region worthy of anatomic dis­ tinction. Using an imaginary line drawn from the

angle of the jaw to the mastoid process, it may be localized approximately 6 cm inferior to the mid­ point of this line at the posterior border of the sternocleidomastoid muscle (Figs 1-20 & 1-21). This neural-rich zone sits approximately at the level of the hyoid bone or the third cervical ver­ tebra. Alternatively, the region may be identified roughly as an area near the junction of the ­upper and middle thirds of the sternocleidomastoid muscle along its posterior border. Interestingly, this neural-rich zone has often and erroneously received distinction as “Erb’s point.” Dr Wilhelm Heinrich Erb (1840–1921), a renowned German physician known widely for his prolific contributions to the field of neuro­ logy, described and illustrated an area on the side of the neck “from a circumscribed point, about two to three centimeters above the ­ clavicle, somewhat outside of the posterior border of the sternomastoid and immediately in front of the transverse process of the sixth cervical vertebra.” He termed this point “Erb’s point” or the “supra­ clavicular point.” Erb noted that at this point,

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Dermatologic Surgery

a lao lls

infraorbital artery levator anguli oris levator labii superioris (reflected)

n z zma

infraorbital nerve zygomaticus minor zygomaticus major

Figure 1-18  Infraorbital foramen and related structures Table 1-13  Nerves that innervate the nose

Infraorbital nerve (V2)

Mid-lower sidewall, ala

External nasal branch of anterior ethmoidal nerve (V1)

Nasal tip

Supratrochlear nerve (V1)

Root, bridge, upper sidewall

Infratrochlear nerve (V1)

Bridge, upper sidewall

“­ simultaneous contraction may be produced in the deltoid, biceps, brachialis anticus, and supi­ nator longus muscles” through transcutaneous electrical stimulation. The neural-rich zone of the cervical plexus within the posterior triangle ­(approximately at the level of the third cervical vertebra) thus lies superior to Erb’s point found just above the clavicle (approximately at the level of the sixth cervical vertebra). We shall refer to the former as “pseudo-Erb’s point.” One motor and four sensory nerves of the cervical plexus emerge approximately 2 cm above or below ­pseudo-Erb’s point along their course in and out of the posterior triangle. The spinal accessory nerve (Table 1-16) is a cranial motor nerve that courses ­posteroinferiorly

through the posterior triangle of the neck. ­Lying deep only to the skin and superficial cervical ­fascia, the nerve is vulnerable to injury during routine surgical procedures such as the punch biopsy. The cervical plexus lies deep to the sternoclei­ domastoid muscle. It is assembled from the ven­ tral rami of the first four cervical nerves. The most prominent peripheral branches that arise from this plexus are derived from the second through fourth (C2–C4) cervical nerves (Table 1-17). The lesser occipital nerve (C2) emerges from behind the sternocleidomastoid muscle and runs parallel to its posterior edge to innervate the neck, mastoid area, and scalp posterior to the ear. The great auricular nerves (C2 and C3) passes around the posterior border of the sternocleidomastoid muscle and ascends vertically towards the ­parotid gland and earlobe (Fig. 1-22). The external ­jugular vein runs in close approximation to the great ­auricular nerves as they cross the superficial border of the sternocleidomastoid. The transverse cervical nerves (C2 and C3) sharply curve anteromedially upon exiting the posterior triangle, running between the ­ external jugular vein and the sternocleidomastoid ­muscle.

Table 1-14  Regional sensory innervation of the trigeminal nerve

Ophthalmic (V1) Nasociliary

Root of nose, medial canthus, dorsum of nose, nasal tip, columella, a portion of upper eyelid, and cornea

Frontal (supratrochlear and supraorbital branches)

Medial upper eyelid and conjunctiva, forehead, and frontal scalp

Lacrimal

Lateral upper eyelid

Maxillary (V2)

1

B ox 1 - 4

Muscles of mastication innervated by the trigeminal nerve • Masseter • Temporalis • Medial pterygoid • Lateral pterygoid • Tensor veli palatini • Lylohyoid • Anterior belly digastric • Tensor tympani

Infraorbital

Lower eyelid, medial cheek, lateral portion of nose, nasal ala, and upper lip

Zygomaticofacial

Malar eminence

Zygomaticotemporal

Medial temple and supratemporal scalp

Superior alveolar and palatine

Upper teeth and gingiva, palate, and nasal mucosa

Mandibular (V3) Auriculotemporal

Chapter

Surgical anatomy of the head and neck

Lateral ear including tragus, lateral temple, temporoparietal scalp, and temporomandibular joint

Buccal

Cheek, buccal mucosa, and gingiva

Inferior alveolar

Mandibular teeth; lower lip and chin (via mental nerve)

Lingual

Anterior two thirds of the tongue, floor of the mouth, and lower gingiva

Neither the great auricular nerve nor the ­transverse cervical nerve supplies the skin of the ­posterior triangle, as they leave the region ­quickly. The fourth branch of the cervical plexus, the ­supraclavicular nerve (C3 and C4), emerges from pseudo-Erb’s point to innervate the skin of the lower neck, clavicle, shoulder, and upper chest. For completeness, the posterior midline scalp is innervated by the greater occipital nerve (C2) and the third occipital nerve (C3). Neither develops from the cervical plexus. The platysma muscle overlies and grants protection only to structures at the inferomedial border of the posterior tri­ angle, such as the external jugular vein and the transverse cervical nerve. It is not a ­reliable struc­ ture that protects the major motor and sensory nerves of this region.

Sensory innervation of the ear Key Points • See Figure 1-�2 for anatomic terms used to describe the features of the ear.

• The innervation of the ear is supplied by

the auriculotemporal nerve (a branch of the trigeminal nerve), great auricular nerve, and lesser occipital nerve (the latter two are branches of the cervical plexus) (Table 1-18).

The ear can be described with a cranial surface (medial or closest to the scalp) and a lateral sur­ face (visible surface in anatomic position). The auricle is the entire visible part of the external ear. It is divided into cartilaginous and noncarti­ laginous (lobule) domains. The great auricular nerve supplies the anterior and posterior portions of the ear lobule, inferior cranial surface, and posterior portion of the lateral surface (portions of the helix and antihelix). The lesser occipital nerve innervates the upper portion of the cranial surface. The auriculotemporal nerve supplies the majority of the lateral portion of the ear including the tragus and crus of the helix. The conchal bowl is variably innervated by branches of the vagus and facial nerves.

Arterial and venous supply of the face Key Points • The facial blood supply is derived from the

external and internal carotid arterial systems.

• The facial artery runs with the marginal mandibular branch of the facial nerve near the masseter.

• Most central facial blood vessels anastomose with their contralateral counterpart along the midline.

• Dermatologists should be aware of multiple

danger zones along the superficial face where named arteries may be injured during surgery.

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Dermatologic Surgery

dao dli fa ila m

depressor anguli oris depressor labii inferioris (transected) facial artery inferior labial artery mentalis

ma mf mn orb

mental artery mental foramen mental nerve orbicularis oris

Figure 1-19  Mental foramen and related structures Table 1-15  The posterior triangle

Boundary Anterior

Posterior border of sternocleidomastoid muscle

Posterior

Anterior border of trapezius muscle

Inferior (base)

Middle third of clavicle

Roof

Skin, SMAS, platysma (variable), deep fascia of neck (variable)

Floor

Splenius capitis, levator scapulae, and scalene muscles

Contents Motor nerves

Spinal accessory (cranial nerve XI)

Sensory nerves

Lesser occipital (C2), great auricular (C2,C3), transverse cervical (C2,C3), supraclavicular (C3,C4)

The superficial arterial supply of the face encom­ passes a vast network of vessels derived from both the external and internal carotid vascular systems (Fig. 1-23, Table 1-19). The dual contribution and intricate anastomoses among each system create a redundant blood supply that bathes the skin and underlying structures richly with oxygen and ­essential nutrients. The premiere facial branch of the external ­carotid system is the facial artery. This ­principal ­vessel carves a tortuous path throughout its course over the superficial face, delivering ­ multiple branches as described in Table 1-20. The facial ­artery debuts on the superficial face at the anteroin­ ferior angle of the masseter muscle over the body of the mandible (see Fig. 1-� 9). Here the marginal mandibular branch of the facial nerve may be found along with the facial artery. This ­potential

Chapter

Surgical anatomy of the head and neck

1

Transverse cervical nerve Lesser occipital nerve Great auricular nerve Spinal accessory nerve [XI]

Trapezius muscle

Sternocleidomastoid muscle

Clavicle

Supraclavicular nerves Figure 1-20  Illustration of the posterior triangle of the neck

danger zone is protected by the ­ overlying skin, subcutaneous tissue, SMAS, and platysma. Along its course, the facial artery runs deep to the riso­ rius and zygomaticus muscles, anterior to the buccinator, and variably anterior or posterior to the levator labii superioris. After the lateral nasal branch splits from the facial ­artery near the nasal ala, the terminal facial artery is known as the angular artery (Fig. 1-24). After the facial artery branches off, the external carotid artery divides into two terminal branches – the maxillary artery and the ­superficial ­temporal artery. The internal maxillary artery runs a deep course within the head. It contains four pertinent branches that supply blood to the ­superficial face (Table 1-21). The superficial temporal artery (STA) arises within the parotid gland and ascends superiorly over the posterior aspect of the zygomatic proc­ ess. It terminates by bifurcating into two divisions, both of which enter the temporal fossa (Table 1-22). The STA courses along with, and anterior to, the auriculotemporal nerve (see Fig. 1-� 2). The internal carotid system contributes to the arterial supply of the superficial face through its ophthalmic arterial branches (see Fig. 1-17, Table 1-23). The internal and external carotid systems

unite superior to the medial canthal ligament where the dorsal nasal and angular artery anas­ tomose. Table 1-24 reviews the regional blood ­supply of the face. Peripheral pulses may be palpated over cer­ tain anatomical regions of the face (Table 1-25). The superficial location of the vessels in these areas renders them susceptible to trauma dur­ ing surgical procedures. Physicians should always ­recognize these “danger zones” prior to any surgi­ cal procedure in the area.

Venous supply of the face Key Points • Veins of the face run parallel to the arteries. • Superficial regions of the face drain to the internal jugular venous system.

• Deep regions of the face drain to the external jugular venous system.

Figure 1-23 and Table 1-26 review the veins of the face. The supratrochlear and supraor­ bital veins unite to form the facial vein near the ­medial canthus. The facial vein runs posteroinfe­ riorly and merges with the anterior branch of the ­retromandibular vein inferior to the mandible.

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Dermatologic Surgery

ga lo san sc

great auricular nerve lesser occipital nerve spinal accessory nerve supraclavicular nerve

scm tc tpz

sternocleidomastoid muscle transverse cervical nerve trapezius muscle

Figure 1-21  Anatomy of the posterior triangle of the neck (Erb’s point) Table 1-16  Spinal accessory nerve

Innervation

Trapezius and sternocleidomastoid (SCM) muscles

Course

Travels along a line connecting junction of upper and middle third of sternocleidomastoid to junction of middle and lower third of trapezius

Damage

Drooping of ipsilateral shoulder or “winged scapula” (trapezius) Inability to raise and retract ipsilateral shoulder (trapezius) Weakness in turning head to contralateral side against resistance (SCM)

As the facial vein drains the majority of the face, it travels posteriorly and superficial to the facial artery. The facial vein terminally drains into the internal jugular vein.

Within the parotid gland, the superficial tem­ poral and maxillary veins unite to form the retro­ mandibular vein, which then descends between the external carotid artery and the deeper ­positioned facial nerve. The retromandibular vein bifurcates into an anterior branch (above) and a posterior branch. The posterior limb coalesces with the posterior auricular vein to form the ­external jugular vein. Veins of the face do not contain valves and are subject to potential retrograde flow. The superior ophthalmic vein is contiguous proximally with the cavernous venous sinus of the dura mater covering the brain. Distally, the superior ophthalmic vein connects with the angular vein. Superficial midfa­ cial thrombophlebitis with involvement of the fa­ cial vein may result in retrograde flow of bacteria to the dural venous system. Care must be taken to avoid squeezing large pustules or ­furuncles of the midfacial region to avoid seeding the blood and dura with bacteria, given the above anatomy.

Table 1-17  Sensory nerves of the cervical plexus

Nerve

Spinal rami

Cutaneous area supplied

Great auricular

C2 and C3

Lateral neck, angle of jaw, skin over parotid gland, anterior and posterior ear lobule, inferior cranial surface of ear, and posterior portion of lateral surface of ear

Lesser occipital

C2

Neck, mastoid area, and scalp posterior to the ear; superior portion of cranial ear

Transverse cervical

C2 and C3

Anterior neck

Supraclavicular

C3 and C4

Lower neck, clavicle, and shoulder

The lymphatic system of the head and neck Key Points • Lymphatic drainage flows in an inferior and

diagonal direction away from the head towards the deep lymph nodes in the neck. • Flow is superficial to deep. • Lymphatic vessels contain valves. • The superficial collecting nodes drain to the deep cervical nodes.

Knowledge of the lymphatic drainage of the head and neck is essential for evaluation of ­malignancy and infection of the skin (Fig. 1-27). The lymphatic system begins with fine lymphatic capillaries in the superficial dermis that con­ nect with larger lymphatic vessels deeper in the skin. Unidirectional flow into lymph nodes and ­lymphatic chains ultimately returns fluid to the venous circulation at the junction of the internal jugular and subclavian veins via the thoracic and right lymphatic duct. The clinically important lymph nodes of the head and neck are listed in Table 1-27. The lymphatic drainage of the scalp and face ­follows a predictable pattern (Table 1-28), ­although the drainage can be variable for each patient. The above groups of superficial collecting lymph nodes ultimately drain to the superficial and deep lateral cervical nodes. The superficial lateral cervical nodes lie above the sternocleido­ mastoid muscle and are associated with the ­external jugular vein. The deep lateral cervical nodes run below the sternocleidomastoid muscle with the internal jugular vein. The deep cervical nodes form a triangular pattern with the spinal accessory, transverse cervical, and internal jugular chains forming the superomedial, inferior base,

Chapter

Surgical anatomy of the head and neck

1

and ­superolateral arms respectively. The internal jugular chain is the major collecting system of the head and neck. See Table 1-30 for the areas that drain to each chain.

The anatomy of the scalp Key Points • The scalp is the soft tissue that covers the cranium and is made up of five layers.

• The forehead and temple are components of the scalp, embryologically speaking.

• Regions of the scalp include: frontal, temporal, parietal, occipital, vertex, and crown.

• The vertex lies at top of the scalp anterior to the crown.

• The galea aponeurotica is a component of the

superficial musculoaponeurotic system (SMAS).

• Infection of the scalp can spread to the meninges via emissary veins.

The layers of the scalp are summarized in Box 1-� 5 and Figure 1-28 using the mnemonic SCALP. Its borders are delineated in Table 1-31. The skin of the scalp contains many hair follicles and sebaceous glands that slice into the subcutane­ ous fat. A rich network of nerves and blood vessels traverses the connective tissue layer. This second layer also contains thick fibrous bands (retinacula) that connect the skin to the galea aponeurotica and form the support network for the blood ves­ sels. When these vessels are cut, the thick bands hold the vessels open allowing the scalp to bleed profusely. Consequently, under­mining in this plane is suboptimal due to decreased visualization from excessive bleeding and significant resistance to movement from retinacular attachments. The third layer of the scalp, the galea aponeu­ rotica, contains two layers of fascia that encase and unite the bellies of the occipitofrontalis muscle through an intervening inelastic fascial membrane. The galea is the strongest layer of the scalp, and wounds superficial to it do not spread. Together with the skin, it functions as a unit that can move freely over the deeper layers. As the frontalis and occipitalis muscles pull the scalp in opposite ­directions, incisions that interrupt the galea in a coronal plane increase the mobility of this inelas­ tic membrane. Cutaneous surgeons may exploit this tendency by making a small coronal incision, or galeotomy, anterior or posterior to wound edges to relax tension forces and permit easier closures. The loose areolar tissue of the scalp attaches the galea aponeurotica to the periosteum. This relatively avascular layer provides the optimum site for undermining in the scalp. Although the looseness of this space permits mobility of the skin and galea, it creates a potential space where large amounts of blood can collect after trauma or surgery. Posterior and posterolateral bony

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Dermatologic Surgery

ejv ga l

external jugular vein great auricular nerve ear lobule

pg scm

Figure 1-22  Great auricular nerve and external jugular vein

parotid gland sternocleidomastoid muscle

Table 1-18  Sensory innervation of the ear

Nerve

Anatomic location

Great auricular

Majority of anterior and posterior auricle: helix, antihelix, antitragus, entire lobule

Auriculotemporal

Anterocranial auricle above external auditory meatus: tragus, anterior crus and rim of helix, anterior half of external auditory canal

Lesser occipital

Small segment of posterior auricle and pre-mastoid skin

Facial, vagus (cranial nerve X), and glossopharyngeal (cranial nerve IX) nerves

Posterior half of external auditory canal, skin of concha, antihelix, tragus, and antitragus, posterior auricle–mastoid junction

i­nsertions of the scalp prevent the spread of ­fluid or infection to the neck (Table 1-32). Lateral spread is contained at the zygomatic arch, the ­insertion site for the temporal fascia. However, as

Chapter

Surgical anatomy of the head and neck

1

no bony insertions exist over the anterior bound­ ary, infection or blood from the scalp may track into the eyelids and root of the nose. Infection in loose areolar tissue can also spread to the ­meninges via emissary veins that pass directly to the dura (see below). The final and deepest layer, the periosteum, is adherent to the bones of the cranium by connec­ tive tissue fibers known as Sharpey’s fibers. The muscles of the scalp are summarized in Table 1-33. The sensory innervation of the scalp is provid­ ed by six nerves, summarized in Table 1-34. When anesthetizing the scalp, the anesthetic should be placed superficial to the galea aponeurotica, as branches from these six nerves run in the connec­ tive tissue layer. The arteries that supply the scalp navigate the connective tissue layer. They are derived from both the internal and external carotid arteries (Table 1-35). Rich bilateral anastomoses, in addi­tion to the aforementioned retinacular attachments, explain why ligation of one end of a transected artery is insufficient to stop bleeding.

Supratrochlear artery and vein Supraorbital artery and vein Angular artery and vein Lateral nasal artery and vein

Superficial temporal artery and vein Transverse facial artery and vein

Posterior auricular vein Posterior auricular artery Occipital vein Occipital artery

Superior labial artery Inferior labial artery Marginal mandibular nerve Facial artery and vein External carotid artery Figure 1-23  Arterial and venous supply of the face

External jugular vein Internal jugular vein

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Dermatologic Surgery Table 1-19  Pertinent facial arterial supply

Branches of external carotid artery (ECA) system

Branches of internal carotid artery (ICA) system

Facial artery

Ophthalmic artery branches

Internal maxillary artery Superficial temporal artery

Table 1-20  Facial artery branches (external carotid system)

Branch

Origin

Course

Comments

Supplies

Inferior labial (Fig. 1-25)

Inferior to oral commissure

Runs anterosuperior deep to depressor anguli oris before penetrating orbicularis oris

Sandwiched between orbicularis oris and mucous membrane as it travels along the margin of the lower lip

Labial glands, muscles, skin, and mucosa of lower lip

Superior labial (Fig. 1-26)

Just superior to inferior labial artery

Runs deep to depressor anguli oris before penetrating orbicularis oris; sandwiched between orbicularis oris and mucous membrane as it travels along margin of upper lip

Has a septal branch that runs superiorly along columella to nasal tip and an alar branch that runs superiorly towards nasal ala

Labial glands, muscles, skin, and mucosa of upper lip, nasal septum and alae

Lateral nasal

Near superior alar groove

Runs medially towards dorsum of nose

Has extensive anastomotic branches with septal, alar, dorsal nasal, and contralateral lateral nasal arteries

Skin of nasal alae, soft triangle, dorsum, and tip

Angular

Terminal branch of facial artery after lateral nasal branch departs

Towards medial canthal ligament along nasal sidewall

Anastomoses with dorsal nasal artery superior to medial canthal ligament

Skin of cheek, elevators of upper lip, orbicularis oculi, and nasal sidewall

The veins of the scalp accompany the arter­ ies and are similarly named. They anastomose with the diploic veins of the cranial bones and ­intracranial dural sinuses via emissary veins which lack valves. Subsequently, infection from the scalp can spread in a retrograde flow to the meninges via these valveless veins.

Skin cancer on the scalp can metastasize to the lymph nodes of the head and neck. The scalp anterior to the ears drains to the parotid, sub­ mandibular, and deep cervical lymph nodes. The posterior scalp is drained by the occipital and pos­ terior auricular lymph nodes.

aa fa ln

angular artery facial artery lateral nasal branch (facial artery)

Figure 1-24  Facial artery with angular artery

Chapter

Surgical anatomy of the head and neck

1

31

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Dermatologic Surgery

dao dli fa ila

depressor anguli oris depressor labii inferioris (reflected) facial artery inferior labial artery

m mf orb

mentalis mental foramen orbicularis oris

Figure 1-25  Inferior labial artery and related structures of the lower lip and chin

a b c d,e

superior labial artery (SLA) septal branch of SLA alar branches of SLA levator labii superioris alequae nasi alar and labial branches

f g h i

levator labii superioris levator anguli oris zygomaticus minor zygomaticus major

Figure 1-26  Superior labial artery and related structures of the upper lip and cheek

Chapter

Surgical anatomy of the head and neck

1

33

34

Dermatologic Surgery Table 1-21  Pertinent internal maxillary artery branches (ECA system)

Branch

Description

Inferior alveolar (see Fig. 1-19)

Origin on face: exits mental foramen as mental artery

Masseteric

Course: along posterior surface of masseter

Buccal

Course: along anterior surface of buccinator

Infraorbital (see Fig. 1-18)

Origin on face: exits infraorbital foramen along with infraorbital nerve

Supplies: skin and muscles of the chin

Comments: emerges deep to levator labii superioris Supplies: skin and muscles of cheek with extensive branching superiorly, medially, inferiorly, and laterally

Table 1-22  Superficial temporal artery branches (ECA system)

Branch

Description

Transverse facial (see Figs 1-3 & 1-4)

Origin: within parotid gland Course: traverses across face between inferior border of zygomatic arch (one fingerbreadth below) and parotid duct Comments: lies on masseter muscle; often travels with zygomatic or buccal branches of cranial nerve VII Supplies: parotid gland and duct, masseter, and skin of cheek

Frontal branch

Course: terminal division running anterosuperiorly Supplies: skin, muscles, and periosteum of frontal forehead

Parietal branch

Course: terminal division running posterosuperiorly Supplies: skin, muscles, and periosteum of parietal forehead

Table 1-23  Ophthalmic artery branches (ICA system)

Branch

Description

Dorsal nasal

Origin: terminal branch of ophthalmic artery Course: exits orbit superior to medial canthal ligament before anastomosing with angular artery Comments: two terminal branches exist, one runs medially across nasal root and the other inferiorly along dorsum of nose Supplies: nasal root, dorsum, and tip

Supratrochlear

Origin: terminal branch of ophthalmic artery Course: superomedially along mid-forehead Comments: arterial base of paramedian forehead axial pattern flap; travels with supratrochlear nerve Supplies: mid-forehead and anterior scalp

Supraorbital

Origin: exits supraorbital foramen along with supraorbital nerve Course: superficial and deep branches run superolaterally along forehead Supplies: mid and lateral forehead, anterior scalp

Lacrimal

Course: with lacrimal nerve, runs towards the lacrimal gland, eyelids, and conjunctiva

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Surgical anatomy of the head and neck

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Table 1-24  Regional blood supply

Region supplied

Artery of ECA system

Artery of ICA system

Scalp and forehead

Superficial temporal

Supraorbital

Posterior auricular

Supratrochlear

Occipital Eyelid and periorbital

Frontal branch of STA

Lacrimal

Transverse facial

Supraorbital

Infraorbital

Supratrochlear

Zygomatico-orbital External nose

Lateral nasal

Dorsal nasal

Superior labial (septal/alar) Transverse facial

Cheek

Infraorbital Buccal Facial and angular Lips and oral cavity

Superior labial Inferior labial Buccal Inferior alveolar (mental)

Ear

Superficial temporal (supplies anterior auricle and external auditory meatus) Occipital (supplies posterior auricle) Posterior auricular (supplies posterior auricle)

Table 1-25  Arterial pulses and danger zones of the face

Facial artery

With the jaw firmly clenched, the artery may be palpated at the anteroinferior border of the masseter muscle as this muscle inserts on the body of the mandible

Facial artery

Grasp the cheek between the first and second fingers about one fingerbreadth lateral to the oral commissure

Angular artery

Palpated just inside the medial canthus against the nasal sidewall, also along the naso–cheek junction as it ascends to the medial canthus

Superficial temporal artery

Palpate the root of the zygomatic process at its superior border just anterior to the tragus

Table 1-26  Veins of the face

External jugular vein tributaries

Internal jugular vein tributaries

Superficial temporal vein

Supraorbital and supratrochlear veins

Maxillary vein

Ophthalmic vein

Retromandibular vein

Infraorbital vein

Posterior auricular vein

Lateral nasal vein

Transverse facial

Labial vein Facial vein Transverse facial

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Dermatologic Surgery

Direction of lymph flow

Preauricular/ parotid nodes

Occipital nodes

Postauricular nodes

Jugulodigastric node Submental nodes Submandibular nodes

Deep cervical nodes

Omohyoid muscle Internal jugular vein Jugulo-omohyoid node External jugular vein

Figure 1-27  Lymphatics of the head and neck

Chapter

Surgical anatomy of the head and neck

1

Table 1-27  Lymph nodes of the head and neck

Nodes

Location

Occipital

Apex of posterior triangle near insertion of trapezius and sternocleidomastoid muscles

Postauricular

On mastoid insertion of sternocleidomastoid muscle

Preauricular

Superficial to parotid gland immediately anterior to tragus

Parotid

Clustered within and around parotid gland

Facial

See Table 1-29: Facial group of lymph nodes

Submandibular

Inferior to lower edge of mandible near submandibular salivary glands and facial vein

Submental

In submental triangle (formed by hyoid bone, anterior digastric muscles, and mandible)

Internal jugular chain

Runs along with internal jugular vein deep to sternocleidomastoid muscle

Spinal accessory chain

Runs along with 11th cranial nerve deep to sternocleidomastoid muscle

Transverse cervical chain

Extends from inferior edge of spinal accessory chain to junction of internal jugular and subclavian veins

Table 1-28  Superficial collecting nodes

Area of skin

Lymph nodes draining the area

Scalp posterior to vertex

Postauricular and occipital nodes

Ear lobule

Superficial lateral cervical nodes

Lateral ear superior to lobule

Preauricular node

Cranial ear superior to lobule

Postauricular node

Anterior scalp, forehead, temple, lateral eyelids, nasal root, lateral cheek, external acoustic meatus, superior ear, parotid gland, and buccal mucosa

Parotid nodes

Medial cheek, medial canthus, medial eyelids, central face, nose, upper lip, and lateral lower lip

Facial group of lymph nodes (Table 1-29) and submandibular nodes

Chin, medial lower lip, anterior third of tongue, and buccal floor

Submental nodes

Table 1-29  Facial group of lymph nodes

Nodes

Location

Mandibular

Along external surface of mandible adjacent to facial artery and anterior to masseter muscle

Buccinator

Superficial to buccinator muscle or within buccal fat pad

Infraorbital

Along nasolabial fold

Malar

Superficial to malar eminence, lateral to eye

Table 1-30  Deep lateral cervical nodes

Chain

Nodes/area draining to each chain

Spinal accessory

Occipital, postauricular, and suprascapular nodes

Transverse cervical

Spinal accessory chain, subclavian nodes, and lymphatic vessels from upper chest

Internal jugular

Submental, submandibular, parotid, preauricular and postauricular lymph nodes; ears, tongue, nasal pharyngeal area, paranasal sinuses, teeth, palate, larynx, pharynx, and vocal cords; spinal accessory and transverse cervical chains

B ox 1 - 5

Layers of the scalp Skin (epidermis and dermis) Connective tissue (subcutaneous fat) Aponeurosis (galea aponeurotica) Loose areolar tissue (subgaleal space) Pericranium (periosteum)

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Dermatologic Surgery

Skin; Connective Tissue; Aponeurosis (galea); Loose Alveolar Tissue; Pericranium Figure 1-28  Layers of the scalp

Table 1-31  Borders of the scalp

Anterior

Supraorbital ridges

Posterior

Base of occipital bone

Lateral

Frontal process of zygomatic bone, zygomatic arch, external acoustic meatus, mastoid process, and superior nuchal line of occipital bone

Table 1-32  Boundaries of the loose alveolar space

Posterior

Superior nuchal line of occipital bone

Posterolateral

Mastoid process of temporal bone

Lateral

Temporal fascia

Anterior

Frontalis muscle insertion points on skin and subcutaneous connective tissue

Table 1-33  Muscles of the scalp

Frontalis

Occipitalis

Origin

Galea aponeurotica

Superior nuchal line of occipital bone

Insertion

Skin and muscular fascia of upper eyelids

Galea aponeurotica

Innervation

Temporal branch of facial nerve

Posterior auricular branch of facial nerve

Action

Raises eyebrows; allows skin to slide over bones of cranium

Not under voluntary control; allows skin to slide over bones of cranium

Chapter

Surgical anatomy of the head and neck

1

Table 1-34  Nerves of the scalp

Origin

Scalp area innervated

Supratrochlear nerve

Ophthalmic division of trigeminal nerve

Frontal scalp up to vertex in medial plane

Supraorbital nerve

Ophthalmic division of trigeminal nerve

Frontal scalp up to vertex lateral to supratrochlear nerve

Zygomaticotemporal nerve

Maxillary division of trigeminal nerve

Scalp nearest temple

Auriculotemporal nerve

Mandibular division of trigeminal nerve

Temporal region of scalp

Lesser occipital nerve

Cervical plexus (C2)

Lateral occipital region

Greater occipital nerve

Dorsal ramus of second cervical nerve (C2)

Medial posterior scalp from occipital region to vertex

Table 1-35  Arterial supply of the scalp

Proximal artery

Distal branch

Region supplied

Internal carotid

Supratrochlear artery

Medial forehead; crown and vertex (minor)

Supraorbital artery External carotid

Superficial temporal artery Posterior auricular artery

Lateral forehead, occiput, temporoparietal scalp, crown and vertex (major)

Occipital artery

Further reading Asarch RG. A review of the lymphatic drain­ age of the head and neck: use in evaluation of potential metastases. J Dermatol Surg Oncol 1982;8(10):869–872. Baker DC, Conley J. Avoiding facial nerve injuries in rhytidectomy. Anatomical variations and pitfalls. Plast Reconstr Surg 1979;64(6):781–795. Bennett RG. Fundamentals of Cutaneous Surgery. Washington, DC: CV Mosby, 1988. Breisch EA, Greenway HT. Cutaneous Surgical Anat­ omy of the Head and Neck. New York: Churchill Livingstone, 1992. Carlson KC, Roenigk RK. Know your anatomy: perineural involvement of basal and squamous cell carcinoma on the face. J Dermatol Surg Oncol 1990;16(9):827–833. Erb W. Handbook of Electro-Therapies (Translated by Putzel L.) William Wood and Company. New York. 1883; 122-124. Accessed online at: http://books. google.com/books?q=handbook+of+electro+  therapeutics Gosain AK. Surgical anatomy of the facial nerve. Clin Plast Surg 1995;22(2):241–251. Harding SP, Lipton JR, Wells JC. Natural history of herpes zoster ophthalmicus: predictors of post­ herpetic neuralgia and ocular involvement. Br J Ophthalmol 1987;71(5):353–358. Moore KL, ed. Clinically Oriented Anatomy, 3rd edn. Baltimore: Williams & Wilkins, 1992.

Reich SG, Grill SE. Gustatory sweating: Frey syn­ drome. Neurology 2005;65(11):E24. Robinson JK, Anderson ER. Skin structure and surgi­ cal anatomy. In: Robinson JK, Hanke CW, Sen­ gelmann RD, Siegel DM, eds. Surgery of the Skin: Procedural Dermatology. Philadelphia: Elsevier Mosby, 2005. Robinson JK, Hanke W, Sengelmann RD, Siegel DM. Surgery of the Skin: Procedural Dermatology. St Louis: Elsevier Mosby, 2005. Salasche SJ, Berstein G, Senkarik M. Surgical Anato­ my of the Skin. Norwalk: Appleton & Lange, 1988. Scarborough D, Bisaccia E, Schuen W, Swensen R. Anesthesia for the dermatologic surgeon. Int J Dermatol 1989;28(10):629–637. Standring S, Healy J, Johnson D, Williams A. Gray’s Anatomy: The Anatomical Basis of Clinical Prac­ tice. New York: Elsevier Churchill Livingstone, 2005. Tart RP, Mukherji SK, Avino AJ, Stringer SP, ­Mancuso AA. Facial lymph nodes: normal and abnormal CT appearance. Radiology 1993;188(3):695–700. Tolhurst DE, Carstens MH, Greco RJ, Hurwitz DJ. The surgical anatomy of the scalp. Plast Reconstr Surg 1991;87(4):603–614. Tubbs RS, Loukas M, Salter EG, Oakes WJ. Wilhelm Erb and Erb’s Point. Clin Anat. 2007;20:486–488.

39

Gregory J. Fulchiero Jr, Christopher Riddell Jones, and Christie T. Ammirati

Key Points • Most surgical site infections are the result of

wound contamination at the time of surgery.

• Four potential sources of infection are: the

patient, surgical personnel, the surgical environment, and surgical instruments (including suture). • Surgical site infections are defined as any surgical wound that produces pus within 30 days of the procedure. • Staphylococcus aureus is the most frequent cause of wound infections in dermatologic surgery. • The surgeon’s hands should be washed before donning gloves and after their removal. • Alcohol-containing preparations are flammable and must be allowed to dry completely before electrocautery or lasers are used. • Povidone–iodine has broad-spectrum activity but must remain on the skin to have a prolonged effect. • Chlorhexidine gluconate has sustained broadspectrum activity but is toxic to the cornea and the middle/inner ear. • Shaving hair at the surgical site causes microabrasions that increase the risk of infection. When possible, hair should be left in place or clipped with scissors prior to establishing a sterile field. • Good surgical technique avoids compromising the environment of the surgical wound and decreases the risk of infection. This includes: establishing and maintaining a sterile field, atraumatic handling of tissue, effective hemostasis with minimal electrocautery, and limiting the amount of implanted material within the wound. • There is debate over the influence of surgical attire (scrub suit, facemask, disposable booties, surgical cap) on wound infection rate.

Clinical overview Surgical wound infections are relatively rare in dermatologic surgery (incidence 90% of resident aerobes are S. epidermidis)

Staphylococcus aureus

Anaerobic diphtheroids (P. acnes)

Coagulase-negative staphylococci

• Patient’s endogenous flora • Surgical personnel • Surgical environment • Surgical instruments and suture

Gram-negative organisms (Enterobacter, Klebsiella, E. coli, and Proteus spp.)

Enterococcus spp. Escherichia coli

B ox 2 - 2

Group A streptococci

Good surgical technique

Pseudomonas aeruginosa Enterobacteriaceae (Serratia spp., Klebsiella spp.)

• Establishing and maintaining a sterile field • Atraumatic handling of tissue • Effective hemostasis with minimal electrocautery • Limited amount of implanted suture material

Table 2-2  Characteristics of surgical site infection

Objective criteria

Subjective criteria

B ox 2 - 3

Purulent wound drainage

Erythema

Frequent causes of abrupt increase in wound infection rate

Positive wound culture

Induration

>105

Warmth

• Not washing hands before and after each patient contact • Failure to perform an adequate surgical scrub • Poor surgical technique • Inadequate cleanliness of the surgical environment • Bacterial colonization of a member of the surgical team

likelihood of developing an infection for each procedure based on the status of the surgical site and the anatomic location (Fig. 2-1). Dermatologic surgery, in general, carries a low infection rate but surgical wounds of the groin, axilla, mouth, ear, and below the knee may be at a higher risk of postoperative infection (exceeding 5%) (Fig. 2-2).

Risk factors Certain patient risk factors and comorbidities are known to increase the risk of surgical site infection and may warrant the use of prophyl­ actic antibiotics (Box 2-4). A history of previous wound infection may indicate that the patient has chronic bacterial colonization, most frequently with S. aureus, and is at increased risk for subsequent wound infections. Reduced perfusion of the wound bed by either endoge­ nous vascular insufficiency or nicotine-induced vasoconstriction increases the risk of necrosis, dehiscence, and wound infection. ­ Patients with poorly controlled diabetes mellitus are

organisms per gram of tissue

Tenderness Opening of incision postoperatively for any reason Infection as deemed by clinical assessment of the surgeon

at ­ increased risk for Pseudomonas sp. colonization of the ear canal and may be predisposed to infection after auricular surgery, particularly of the conchal bowl. Severe malnutrition and chronic alcoholism are considered immunocompromised states and associated with increased risk of wound infection. Chronic corticosteroid usage, chemotherapy, neutropenia (granulocyte count primary closure > skin grafting > flap. A wound closure algorithm is useful for a systematic approach (Fig. 13-1). Flaps are usually performed when other closures are less optimal due to issues with tension, function, or form. In general, flaps are ideal for reducing, redirecting, and redistributing tension from the primary defect, and for providing bulk or thickness for deeper wounds. Flaps have a wide range of applications and can provide excellent functional and cosmetic outcomes when designed and executed precisely. The goals of this chapter are to discuss: (1) how flaps are classified, (2) the principles and biomechanics of flap movement, and (3) common flap designs in dermatologic surgery.

Definition A flap is a section of partially detached tissue. The attached portion of a flap contains its vascular supply and is its pedicle (Fig. 13-2). All flaps share the following features: • The recruitment of nearby (but not necessarily contiguous) donor skin that is mobile and lax. • The ability to reduce, redirect, and/or redistribute tension from the primary defect (original wound to be repaired). • The creation of a secondary defect once the flap moves into and closes the primary defect. The secondary defect is the space that the donor flap tissue occupied. The tension on the primary defect is partially redirected and redistributed to the secondary defect.

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Dermatologic Surgery B ox 1 3 - 1

Wound analysis Wound characteristics

• The alteration of tension vectors (directional movement under tension) when both primary and secondary defects are closed.

How large is the defect?

Classification

What tissue layers are missing – epidermis, dermis, subcutaneous fat, fascia, muscle?

There are numerous ways to classify flaps (Fig. 13-3):

Is there a need for structural support – bone, cartilage? Is the wound located in a convex or concave region of the body? Are any critical structures exposed – bone, tendon, nerve, vessel)? What caused the wound – malignancy, trauma, infection? If cancer, are the margins clear? What is the risk of recurrence? Will adjuvant therapy (radiation, topical chemotherapy) be necessary? Cosmetic unit, boundary Is the defect in an area of visual significance? Is there baseline asymmetry? What cosmetic units and subunits are involved? What proportion of the subunit is involved? If more than 50%, should the remainder be removed and the entire subunit replaced? What cosmetic boundaries are nearby? Relevant anatomy

• Location with respect to the surgical defect – local, regional, or distant • Movement – advancement, rotation • Vascular supply – random pattern, axial, or microvascular • Stage – single or multistaged • Configuration – note, rhomboid, bilobed, banner, etc. • Eponym – Abbe, Reiger, Mustarde, etc. No single classification accounts for every design or definition variation. Eponyms should generally be avoided. Most flaps in cutaneous surgery are local (adjacent and contiguous skin) and regional (nearby but not directly adjacent). Within this context, the most useful classification scheme is based on movement and vascular supply.

Movement

Is the patient willing to undergo a staged reconstruction?

There are two basic local flap movements: linear ­(advancement) and pivotal (rotational) (Table 13-1). Advancement flaps move adjacent/contiguous skin in a linear fashion into the defect. Rotation flaps move adjacent/contiguous tissue in an arc or curvilinear fashion. Although these definitions help in concept and classification, in practice many flaps involve both types of ­movement. A transposition flap may incorporate both a pivotal and a linear movement. However, ­although a pure rotation or advancement flap moves contiguous tissue into a wound, a transposition flap transfers noncontiguous tissue across an inte­rvening area of normal skin to close the primary defect (Fig. 13-4). Local transposition flaps are one-stage procedures (excluding revisions). Regional transposition flaps, however, are staged repairs (more than one stage for completion) and are also known as interpolation (interpolate = to insert between parts) flaps. Interpolation flaps or staged flaps, therefore, are subtypes of transposition by moving tissue across areas of unaffected skin to reach the wound.

Wound care compliance?

Vascular supply

May patient comorbidities (venous stasis, diabetes, smoking) affect wound healing?

The vascular supply or pedicle to a flap is the portion that remains attached. A pedicle may be random or axial based. Random pattern flaps include all local flaps and are nourished by dermal and subdermal vascular plexus. Axial flaps are regional and are based on a named artery ­(either ­ septocutaneous or musculocutaneous,

Where are the regional relaxed skin tension lines and rhytids? Is there baseline functional compromise – nerve injury/palsy, ectropion, nasal valve collapse, etc.? What free margins are affected – eyelids, nose, lips? What neurovascular structures are at risk? Is the location in an area of inherent high tension – extremity, trunk? Adjacent skin Where is there lax and mobile skin – donor reservoir? What is the quality of the adjacent skin – Thickness? Elasticity? Sebaceousness? Compromised (actinic damage, prior scarring or radiation)? Hair growth patterns? How does positional change (upright versus supine, static versus dynamic) affect the defect and closure plans? Patient-specific considerations What are the patient’s aesthetic expectations?

Does the patient take any prescription and/or over-the-counter products that may complicate reconstruction – anticoagulants, antineoplastic, immunomodulating medications, herbal supplements?

Chapter

Flaps

13

No: FTSGd Vascular base poor?

Yes: STSGe or allograft/xenograft

Superficial

Second intentc Low tension: Primary closure or delayed FTSG

Defecta Degree of tension?

Moderate tension: Plication + primary, local flap, or delayed FTSG Yes: Local flapf

Deepb

High tension: Is there adjacent tissue laxity?

No: Composite graftg, regional flapf

No Structural support? Yes: Cartilage graft

Local or regional flap

Figure 13-1  Algorithm for defect closure. The algorithm is not all inclusive. Repair depends greatly on the location of the defect; for instance, a 1-cm defect on the nose demands greater consideration and complexity than a wound of the same size on the cheek. aSmall (3 cm). Location is critical. bDefects greater than 3 mm in depth will likely heal with a contour depression (unless in concave area), especially if overlying convex surfaces or sebaceous skin. cSmall, superficial defects in concave areas are ideal for second intention healing. Avoid second intention if bare bone, tendon, or neurovascular structures are exposed. Large defects will also heal well if superficial. However, anticipate significant wound contraction and its impact, if any, on free margins or function. dA full-thickness skin graft (FTSG) may be applied to any defect that is well vascularized. Superficial defects with FTSGs will maintain contour. If deep defects are repaired with FTSGs, contour depressions may result unless delayed (partial granulation to fill the depth) skin grafting is performed. eSplit-thickness skin grafts (STSGs) have less metabolic demand and survive better in poorly vascularized defects. However, significant graft contraction (with potential effect on free margins) is assured compared with FTSGs. fCombination closures (flap + flap, flap + graft, flap + second intention) should be considered for wounds involving multiple subunits. gComposite grafts work best for small deep wounds at free margins. Owing to their bulk and high metabolic demand, composite grafts survive poorly if sized above 1.5 cm

e.g. ­ supratrochlear artery in a paramedian forehead flap, labial artery in a lip-switch flap) (Table 13-2). All axial flaps are multistaged flaps. Not all staged flaps, however, are axial in vascular supply. The cheek to nose staged flap, for example, is a random pattern flap (incorporates arterial perforators from the angular artery but the angular itself is not in the flap pedicle), despite being a two-stage repair. Due to a more robust and reliable vascular supply, axial designs permit flaps to reach farther and close more complex defects. Axial flaps can even become free flaps if the ­vessels are divided, and the flap is moved and reanastomosed with microsurgical techniques at the recipient site.

Flap biomechanics and design The physics mantra “for every action, there is an equal and opposite reaction” is applicable to flap design. Poor flap design may have deleterious

outcomes, such as inadequate flap length, tissue ischemia, edema, and/or inability to close the secondary defect. The best flap designs must account for and overcome a variety of tissue restraints. All flap movement is limited by inherent, vertical, and lateral restraints. Inherent restraint refers to the intrinsic laxity of the flap tissue. For example, scalp tissue is more restrained than cheek skin due to the inherent rigidi­ ty of the galeal fascia. Similarly, the sebaceous nasal tip is more restrained than the nasal sidewall. Flap design must compensate for inherent tissue restraint. A rotation flap on the scalp must be greater than the 3–4 : 1 ratio (flap diameter = 3–4 × defect diameter) because of the scalp’s reduced mobility. Vertical restraint refers to the fibrous fibers that tether the flap to its base. Vertical restraints are released by appropriate undermining. A form of restraint that combines both inherent and vertical restraint is pivotal restraint, which is a term that

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Dermatologic Surgery

a

b

c

d

Figure 13-2  Flap lexicon. (a) A = primary defect; B = pedicle, attached portion of flap; C = primary standing cone (excises redundancy at primary defect). (b) Flap is rotated superiorly to close the defect. Note how the tension from the primary defect is reduced, redirected, and redistributed to the secondary defect (D). (c) Length discrepancy at secondary defect will be excised in the secondary standing cone (E), which is strategically placed at the submentum; (C) is the primary standing cone that has been excised at the temple. (d) Outcome at 6 months

is specific to rotation flaps. It refers to the point (usually between the pedicle and the primary standing cone) on which the flap rotates into the defect. If a door is the flap, then the door hinge is the area of pivotal restraint. Pivotal restraint tethers the flap during rotation so that the flap’s superior leading edge falls short of the superior border of the defect. Wide undermining and elongating the rotation flap height is required to overcome pivotal restraint (Fig. 13-5). Lateral restraints are the attachments of the flap to its periphery (see Fig. 13-5). A cheek flap, for instance, is laterally restrained by its attachments to the temporal and preauricular fascia. Lateral restraints can be overcome only by properly placed incisions. These “relaxing or releasing” incisions separate peripheral anchors and allow

for flap movement. Once these restraint concepts are understood, flap design may begin. Next to flap restraints, the secondary defect closure is the most important factor to consider. When designed accurately, closure of the secondary defect can facilitate flap movement. Improperly designed, however, untoward tension may result with subsequent complications. Closing the secondary defect usually involves lines of unequal lengths, which may be resolved by a number of techniques (see below in Operative technique). An advancement flap is simply a method of displacing a standing tissue cone from the primary defect. The best example is the Burow’s wedge advancement flap (BWAF), in which one standing cone is displaced laterally in a linear fashion (Fig. 13-6). Rarely used advancement flaps are

Chapter

Flaps

13

Flap classification schemes

Location of donor site

Vascular supply

Movement

Local

Regional

Distant

Advancement

Rotation

Donor tissue is adjacent and contiguous with defect

Donor tissue is nearby but not directly contiguous with defect (e.g. paramedian forehead flap)

Distant donor site (e.g. tubed pedicle flap, radial forearm free flap, rectus abdominis free flap, latissimus dorsi flap)

Linear movement

Pivotal movement

Random pattern Dermal, subdermal plexus nourishes flap

Staged

Eponym

Flap is named by its shape (e.g. comet flap, hatchet flap)

Flap is named after its originator (e.g. Abbé flap, Rieger flap)

Axial

Single stage

Multi-staged

Named artery nourishes flap (e.g. septocutaneous, musculocutaneous)

Additional procedures not required

Additional procedures required (e.g. flap delay, flap inset, pedicle division, flap debulking, scar revision)

Transposition

Microvascular

Flap tissue transferred over an area of unaffected skin to reach defect

Division of flap and axial blood supply, followed by reanastmosis by microvascular techniques

Regional transposition (interpolation)

Configuration

Local transposition Flap pedicle contiguous with defect

Flap pedicle is not contiguous with defect

Random pattern pedicle

Axial pedicle

Single stage

Multi-staged

Figure 13-3  Flap classification

the U-plasty or H-plasty, as they result in long narrow pedicles and unnatural box-like incisions (Fig. 13-7). Other variations of advancement flaps, such as A to T or crescenteric designs, are more useful and aesthetic (Figs 13-8–13-10). ­Island pedicle flaps (IPFs) are especially ­ flexible advancement designs. Also known as a Kite or V to Y advancement flap, an IPF is separated from its ­ peripheral skin (hence its label as an ­island). Its only attachment is a subcutaneous or ­myocutaneous pedicle that is either underneath the flap or to its side. Rather than displacing a cone laterally, an elongated standing cone is developed as a flap and advanced directly into the defect. IPFs are the most tissue sparing of all flaps as there is no secondary or primary standing cone resection (Fig. 13-11). IPFs are categorically a local, singlestage advancement flap. However, they may also rotate and or be transposed into the defect.

A rotation flap is more complex, in that the surface area of the defect itself (and its tension) is redirected and redistributed laterally in a curvilinear fashion into the secondary defect. The length, height, and arc of the curvilinear extension determine where the secondary defect is located and how well it closes (Figs 13-12–13-15). An O to Z flap is a bilateral rotation design that is useful for larger defects, especially on the scalp (see Fig. 13-15). Transposition flaps are most demanding in geometric accuracy. Several eponym versions exist, such as DuFourmental, Limberg, and Webster. The most commonly applied designs in dermatologic surgery are the 30° transposition flap ­(Webster), the bilobe, and the trilobe transposition flaps (Figs 13-16–13-19). Z-plasties are a form of transposition flaps used in scar revision. Transposition flaps recruit donor laxity that is

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Dermatologic Surgery Table 13-1  Flap movement: advancement versus rotation

Examples

Advancement flap

Rotation flap

Unilateral designs:

Rotation (Figs 13-12–13-15):

• Burow’s wedge advancement (Fig. 13-6) • Crescentic advancement (can be unilateral or bilateral (Figs 13-8 & 13-10) • V to Y or island pedicle (kite) (Fig. 13-11)

• Cervicofacial rotation (Figs 13-12 & 13-13) • Dorsal nasal flap (Rieger, hatchet) (Fig. 13-14) • O to Z bilateral rotation (Fig. 13-15) • Innervated myocutaneous lip and cheek (Karapandzic) • O to T • Comet flap

Bilateral designs:

Transposition subtype:

• H-plasty • A to T (Fig. 13-9)

• Rhombic or rhomboid (Limberg, Dufourmental) • Webster 30° transposition • Note or Banner flap (Fig. 13-16) • Bilobe (Figs 13-17 & 13-18) • Trilobe (Fig. 13-19)

Interpolation subtype:

Interpolation subtype:

• Retroauricular staged flap – this is a staged flap that has linear movement. However, it may also be classified as a transposition design because it crosses over intervening island of normal skin to reach the defect

• Paramedian forehead flap (Fig. 13-20) • Lip-switch (Abbé) flap • Cheek to nose (melolabial) interpolation (Fig. 13-21)

Movement

Linear

Pivotal (movement is in an arc)

Vascular supply

Random pattern

Random pattern or axial (paramedian forehead flap, lip-switch flap)

Flap : defect ratio

2–4 : 1

2–4 : 1 (flap : defect ratio may be greater with axial flap)

Tension

Tension is reduced and redistributed but is not redirected

Tension is reduced, redistributed, and redirected

Mobility

Recruits some adjacent tissue laxity laterally

Optimizes recruitment of lax donor tissue laterally and distant from the defect

Restraint

Lateral restraint

Pivotal restraint (Fig. 13-5): • Arises from inherent tissue stiffness at the flap’s pivot point and prevents tip of flap from reaching distal margin of operative defect. Secondary movement expected at primary defect

nearby but not directly contiguous with the defect; this is why flap tissue is transferred over an area of unaffected skin. Staged flaps require two or more stages (separated by 2–3 weeks) to complete, not including any revisions (Fig. 13-20). Stage I involves flap harvest, pedicle creation, and coverage of the defect. Stage II usually divides the pedicle and finalizes the repair. However, stage II may also be an intermediate stage in which the flap is partially elevated and debulked (see Fig. 13-20d). If this intermediate step occurs, then pedicle division occurs in stage III (see Fig. 13-20e,f). Staged designs included both random pattern and axial based pedicles. An example of a staged flap that has a random pattern pedicle is the cheek-tonose (melolabial interpolation) staged flap (Fig. 13-21). Indications for staged repairs include:

• Large defects and/or more than 50% subunit loss • Deep defects that require tissue bulk and contour • Infrastructure loss (i.e. cartilage) • Adjacent tissue reservoir inadequate for reconstruction. Supplementary operations in staged flaps may include: • Flap delay – when distal flap perfusion and viability is questionable, flaps may be delayed after incision. • Flap inset – after flap delay, a subsequent procedure is necessary to inset the flap to the recipient site.

a

Chapter

Flaps

13

c

b

Figure 13-4  Rhombic transposition flap. (a) A = primary defect; B = flap; C = intervening area of skin. (b) Transposition flap (B) crosses over an intervening area of unaffected skin (C) to close the primary defect. (c) Closure

Table 13-2  Flap vascular supply: random versus axial pattern flap

Random pattern flap

Axial flap

Illustration

Rotation flap – random pattern

Paramedian forehead flap – axial pedicle (in this example the left supratrochlear artery at the left medial eyebrow is contained within pedicle)

Vascular supply

Dermal and subdermal plexus

Septocutaneous artery or myocutaneous artery

Stages

Usually single stage; occasionally multi-staged – cheek to nose (melolabial) interpolation flap, retroauricular staged flap

Multi-staged (at least two stages)

Length :  width ratio

1.5–4 : 1

Greater than random pattern flap

Example

All single-staged flaps and some multi-staged flaps, such as the cheek to nose (melolabial) interpolation flap and the retroauricular staged flap

Paramedian forehead flap (based on supratrochlear artery)

• Flap debulking – to improve contour and aesthetic outcome, flaps may require incision and removal of excess tissue. • Pedicle division – once a flap has established vascular connection with the recipient site,

Lip-switch interpolation (Abbé) flap (based on labial artery)

the pedicle may be divided, most commonly in 3 weeks’ time. • Scar revision – procedures to optimize surgical scars may include scar excision, Z-plasty, laser, and dermabrasion.

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a

b

Figure 13-5  Pivotal and lateral restraints. (a) Arrows represent lateral restraints that prevent donor tissue mobility. Black arrows are in areas where tissue movement should be avoided to prevent an eclabium. Blue arrows are preferred donor flap tissue. Note how rotation incision (gentian violet) cuts through lateral restraints, thereby releasing their tethers on the flap. Pivotal restraint (PR) is the area on which the flap will rotate into the defect. (b) Pivotal restraint (PR) prevents flap from fully covering the defect and tethers the flap downward. Proper design and wide undermining in this area helps to minimize the anchoring effect of pivotal restraint

a

b

c

Figure 13-6  Burow’s wedge advancement flap closure. (a) The BWAF displaces one standing cone laterally: (B) is the displaced standing cone that extends laterally and linearly to the looser donor cheek and is the same size as (A) or slightly wider; (C) is the linear vector of closure for this advancement flap. (b) Closure lines are camouflaged along natural creases: (A) hides along the nasal dorsum; (B) hides at the melolabial fold, and linear extension hides at the superior alar sulcus. (c) Long-term results demonstrating functional and cosmetic restoration

Preoperative planning The patient should be examined in the upright position in both static and dynamic situations. Baseline and postoperative functional compromise and asymmetry should be noted (i.e. nerve injury/ palsy, ectropion, nasal valve collapse, oral incompetence, etc.). Aesthetic boundaries, relaxed tension lines, rhytids, and, finally, the flap design should be marked prior to infiltration with local anesthetic. The final checklist before the first incision should successfully answer these questions: 1 Has the defect been evaluated accurately? (see Box 13-1) 2 Is the pedicle sufficient to supply this size of flap?

3 Is one flap sufficient or are combination closures needed (more then one flap, flap plus second intention/primary closure/ graft)? 4 Does this design overcome inherent and lateral restraints? 5 How much undermining is needed to overcome pivotal and vertical restraints? 6 Is “reaction for every action” accounted for? In other words: a. What will happen to the surrounding structures at the primary and secondary defect if the flap is moved as drawn? b. Will closing the secondary defect be possible without excessive tension or free margin distortion?

a

Chapter

Flaps

13

b

Figure 13-7  U-plasty advancement flap design and anticipated final suture line conformation if this closure was chosen. (a) U-plasty design displaces two standing cones (A) and (B) laterally compared with the BWAF. These are the same cones that would be excised if the defect were closed primarily. Two parallel linear incisions extend laterally to form the flap; (P) is the long narrow pedicle. (b) Rectangular box shape incision lines are less camouflaged than with a BWAF

a

c

b

Figure 13-8  Crescenteric advancement flap. (a) The crescenteric advancement flap is similar to the BWAF in that one standing cone is displaced laterally (A); however, the displaced standing cone is crescentic in shape (A) rather than triangular, thus conforming better to areas such as the lateral alar curve (shown here) or lateral eyebrow. (b) Suture lines show how the crescenteric cone blends into the lateral alar sulcus. (c) Appearance 1 week after surgery

a

b

Figure 13-9  A to T advancement flap. (a) A to T design: flap incisions camouflaged at mental crease, primary standing cone placed inferiorly. (b) “T” closure as flaps advance bilaterally. Eversion is needed only at the center, where tension is greatest

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Dermatologic Surgery

a

b

c

d Figure 13-10  Bilateral advancement flap. (a) A bilateral crescenteric advancement flap is ideal for larger midline lower lip defects. Two crescenteric standing cones are removed along mental crease. The bilateral movement maintains lip symmetry and minimizes tension on any one side. (b) A wedge of lip (skin, muscle, mucosa) has been removed centrally and crescenteric cones have been resected and advanced medially. Note how crescenteric cones are concealed along mental crease. (c) Final closure. (d) Long-term results

a

b

c

Figure 13-11  Island pedicle flap (V to Y, or kite advancement flap). (a) Length : width ratio of island flap is 2–3 : 1 relative to defect. Smaller white outline is the final flap dimension. (b) Flap incised and pedicle (myocutaneous) created underneath. Circular defect is angulated to enhance aesthetic closure. (c) Closure

7 Where will the primary and secondary standing tissue cones (dog ears) be? 8 Are the incisions placed where they can best be hidden (along subunit boundaries, within rhytids)? 9 Is any anesthesia needed beyond local infiltration (tumescent anesthesia, nerve blocks)? 10 Is the patient in proper position? 11 Are all instruments and supplies available?

Chapter

Flaps

13

Operative technique The surgical field should include the contralateral aspect of the surgical wound (i.e. the entire face should be prepped in the usual sterile fashion). This will allow the intraoperative assessment of flap movement on tissue symmetry and free ­margins. Undermining should be performed to release vertical and pivotal tissue restraint and elasticity,

a

b

c

d

Figure 13-12  Cervicofacial rotation flap. (a) Lateral restraints are circumferential to defect. Dark blue arrows represent best laxity and donor skin, and are released by flap curvilinear incision (white curve). There is also some movement from the medial cheek (light blue arrows); movement from black arrows is undesirable. (b) Flap incised and undermined. Note incision onto upper neck, which serves as a back-cut and releases additional restraint. (c) Flap rotated to close defect; note displacement of defect and tension vectors onto secondary defect (zygoma, preauricular, upper neck). Primary standing cone at medial cheek. (d) Closure – secondary standing cone revised behind ear at postauricular sulcus

a

b

Figure 13-13  Cheek rotation flap. (a) Classic rotation design, which begins rotation curve level with superior edge of defect. Pivotal restraint (P) tethers flap inferiorly and brings its leading edge A down to A′; this leaves a secondary defect below the eyelid (may lead to ectropion once closed). (b) Modified rotation height, which is above the level of the defect’s superior edge. The elevated rotation height compensates for pivotal restraint and minimizes the risk of ectropion. Secondary standing cone excised posteriorly at sideburn.

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Dermatologic Surgery

c

d

Figure 13-13, cont’d (c) Elevated height of flap allows suspension of flap to lateral orbital rim, thus minimizing the gravitational pull on lower eyelid that inevitably occurs with time and wound contraction. (d) Six-month follow-up: there is no ectropion and ipsilateral eyelid is properly supported

a

b

c

d

Figure 13-14  Dorsal nasal rotation flap (Rieger). (a) Rotation flap extended to superior glabella, with back-cut to optimize movement. (b) Flap is broadly undermined – above perichondrium on the nose. (c) Flap rotates inferiorly. (d) Long-term results. Note flap thickness relative to thinner nasal root area

a

Chapter

Flaps

13

c

b

Figure 13-15  O to Z bilateral rotation on scalp. (a) Bilateral rotation design recruits donor laxity from parietal scalp bilaterally. White arrow is tension vector of primary defect. (b) Flap elevated subgaleally and rotated to close defect. Note that tension vectors are redirected and redistributed to smaller secondary defects. (c) Final closure. Length discrepancies resolved by using rule of halves suturing

a

b

c

d

Figure 13-16  Melolabial transposition flap. (a) Flap width B and D must equal defect diameter at points A and C respectively. Flap length is extended to lower melolabial fold to form a 30° angle (*), which prevents standing cone formation. (b) Flap transposes across lateral ala to close the defect. The distal edge of the flap at D will be trimmed. (c) Closure. (d) Long-term results. Note blunting of superior alar sulcus, which is typical of the melolabial transposition flap

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Dermatologic Surgery

a

c

b

Figure 13-17  Laterally based bilobe transposition flap. (a) The pedicle is laterally based (vascular supply from cheek laterally). The length of the primary cone (P) is intentionally longer in order to optimize flap movement, and is placed at the alar sulcus for camouflage. The entire arc of movement from C to A is less than 90°. The diameter of the first lobe (B) equals that of the defect (A). The diameter of second lobe (C) may be equal to or no less than 75% that of the primary lobe. The two arcs radiating from the defect (A) emanate from the mid and superior edges of the defect. These arcs ensure that the first and second lobes are properly positioned and proportioned when rotating towards the defect. (b) The flap is rotated inferiorly and the defect is closed. The primary lobe (B) closes the defect (A), the second lobe (C) moves into where (B) was, and the donor site at (C) is closed linearly along the upper nasal dorsum. (c) Long-term results

a

b

c Figure 13-18  Medially based bilobe transposition flap. (a) Pedicle is medially based (vascular supply from medial nose). Note intentional elongation of primary cone, now positioned at lateral nasal tip. (b) Closure. (c) Long-term results

a

Chapter

Flaps

13

c

b

Figure 13-19  Trilobe transposition flap. (a) Three lobes may be used for larger defects under tension. The first lobe (A) equals the defect diameter; the second and third lobes (B) and (C) may be equal to or less than (A), depending on the laxity of donor skin. Angles of movement from (B) to (A) and from (C) to (B) are 90° of rotation. (b) Closure. (c) Short-term results

a

b

c

d

Figure 13-20  Staged axial flaps. (a) Stage I: a paramedian forehead flap, based on the left supratrochlear artery is being developed to repair complex defect on the left nasal tip (a cartilage batten graft has been inserted across the alar rim defect for infrastructure support). (b) Stage I: the forehead flap has been rotated, transposed, and interpolated 180° inferiorly to close the nasal defect. The supratrochlear artery is within the pedicle tube attached at the left medial eyebrow. (c) Healthy appearance of paramedian forehead flap 3 weeks later, before stage II. (d) Stage II: the flap is partially elevated and excess subcutaneous tissue is debulked for better sculpting of the nasal tip. The vascular pedicle is still attached at the medial eyebrow. Continued

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Figure 13-20, cont’d (e) Stage III: the pedicle is divided and donor site closed primarily. (f) Stage III: pedicle tube is discarded; flap is sculpted and inset into nose. (g) Outcome 6 months after surgery: note restoration of contour, alar rim stability, and symmetry of eyebrows

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Figure 13-21  Cheek to nose staged random pattern flap. (a) Flap based on melolabial fold; defect has cartilage batten graft inserted for support of alar rim. (b) Pedicle is random pattern, based on arterial myocutaneous perforators of nasalis muscles. (c) Cheek flap inset onto nasal alar defect. (d) Long-term results after pedicle division in stage II

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Flaps

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Figure 13-22  Lengthening shorter line. (a) Burow’s wedge advancement flap: note curved upper line (A) that eliminates need for standing cone revision inferiorly (line B) by equalizing line A with line B. (b) Closure without standing cone inferiorly. (c) Final long-term results

and the plane of flap elevation and ­undermining should match the wound depth closely. This should be performed cautiously to minimize injury to vital structures and to maximize the flap’s vascular supply. Flap insetting requires at least two layers of sutures. Subcutaneous–dermal sutures approximate skin edges and minimize wound closure tension on epidermal edges. Suspension or tacking sutures may be necessary to anchor a portion of the flap, in order to shift tension off the leading edge of the flap, reorient tension, and/or reduce ­potential wound dead space. Fascial plication sutures may also be placed to reduce wound tension and defect size. Borders of unequal length will result from the discrepancy between the primary and secondary defects. To equalize this discrepancy, a standing tissue cone (dog ear, Burow’s triangle) may need to be removed from the longer side, or the shorter­ sides may need to be lengthened (Fig. 13-22). ­Alternatively, if the incision lines are long enough (rotation flap with length : width ratio of 4 : 1), the discrepancy may be sewn out either by closing the wound by the “rule of halves.”

Postoperative care Wound care after flap reconstruction is similar to that for most other wounds. A pressure dressing, including ointment and nonstick pad, should be applied over the flap. This initial dressing should be removed after 24–48 h, the area cleaned, and a dressing of ointment, nonstick pad, and tape reapplied. In selected patients, the first dressing change should be performed in the office by the

surgical team, especially in patients with complex dressings and/or intricate reconstructions. Patients and their caretakers should be encouraged to view the wound prior to bandage placement to avoid any surprises with the first dressing change at home. They also should be educated on the anticipated postoperative wound appearance, phases of healing, and potential complications. Written instructions should include recommendations to enhance flap survival, as well as when to seek medical attention.

Summary Aesthetic flap reconstruction requires careful assessment of patient and wound characteristics, an expansive knowledge of surgical anatomy, meticulous flap design and execution, an artistic sense of function and form, and an understanding of flap biomechanics and tissue movement. A systematic approach to design considerations will optimize an outcome that is both functional and beautiful.

Further reading Baker SR. Reconstructive surgery for skin cancer. In: Rigel DS, Friedman RJ, Dzubow LM, Reintgen DS, Bystryn JC, Marks R, eds. Cancer of the Skin. Philadelphia: Elsevier Saunders, 2005: 573–592. Cook JL, Goldman GD. Random pattern flaps. In: Robinson JK, Hanke WC, Sengelmann R, Siegel D, eds. Surgery of the Skin: Procedural Dermatology. St Louis: Mosby, 2005: 311–343.

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Dermatologic Surgery Cook J, Zitelli JA. Axial pattern flaps. In: Robinson JK, Hanke WC, Sengelmann R, Siegel D, eds. Surgery of the Skin: Procedural Dermatology. St Louis: Mosby, 2005: 345–365. Dzubow LM. Facial flaps: biomechanics and regional application. Norwalk: Appleton & Lange; 1990. Fazio MJ, Zitelli JA. Flaps. In: Ratz JL, Geronemus RG, Goldman MP, Maloney ME, Padilla RS, eds. Textbook of Dermatologic Surgery. Philadelphia: Lippincott-Raven, 1998: 223–245. Nguyen TH. Staged cheek-to-nose and auricular interpolation flaps. Dermatol Surg 2005;31(8 Pt 2):1034–1045.

Nguyen TH. The nose. In: Roenigk RK, Ratz JL, Roenigk HH, eds. Roenigk’s Dermatologic Surgery: Current Techniques in Procedural ­Dermatology3rd edn, New York: Informa Healthcare, 2007: 219–230. Stotland MA, Kerrigan CL. Principles of skin flap ­surgery. In: Weinzweig J, ed. Plastic Surgery Secrets. Philadelphia: Hanley & Belfus, 1999: 414–416. Tromovitch TA, Stegman SJ, Glogau RG. Flaps and Grafts in Dermatologic Surgery. St Louis: Mosby, 1989. Verheyden CN, Losee J, Miller MJ, Rockwell WB, Slezak S, eds. Essentials for Students: Plastic Surgery, 6th edn. Arlington Heights, IL: Plastic Surgery Educational Foundation, 1979.

Daihung Vu Do and Christine M. Hayes

Key Points • Skin grafts offer a one-step procedure for repair

of defects in anatomic areas in which there is little skin laxity. • Full-thickness skin grafts are the most commonly performed skin graft and can offer excellent cosmesis if the appropriate donor site is selected. • Split-thickness grafts may be used to cover very large defects but their cosmetic outcome is poorer than that of full-thickness grafts. • Composite grafts are useful for repairing small but deep defects that may include loss of cartilage.

Introduction A skin graft is defined as a piece of tissue harvested from a donor site, separated from its vascular supply, and placed in a distant location. When implanted at the recipient site, the graft must re-establish its vascular supply if it is to survive (Table 14-� 1).

Classification Grafts are classified by their thickness. Split­thickness grafts contain the epidermis and portions of the dermis with little to no adnexal structures. Full-thickness skin grafts include the entire epidermis and dermis as well as adnexal structures. Composite skin grafts contain the complete epidermis, dermis, and deeper structures such as cartilage.

Indications Skin grafts are useful when other options for repair such as primary closure, granulation, and local skin flaps are not ideal. For example, large defects of the nasal tip have little surrounding skin laxity to draw upon and heal poorly with secondary intention. For patients unwilling to undergo a two-stage interpolation flap such as the paramedian forehead flap, grafts can be ideal. They offer a one-step repair procedure that can provide exceptional aesthetic results

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if donor tissues with a good color and texture match can be identified. For deeply invasive ­tumors with a high incidence of local recurrence, a split-thickness skin graft may be the best repair choice so that postoperative surveillance may be facilitated.

Contraindications Before undertaking a graft, the recipient site should be assessed for graft suitability. Of paramount importance is the vascularity of the graft bed. Grafting should be avoided in sites with exposed cartilage or bone because they are poorly vascularized and unable to support a graft. These sites should be allowed to granulate prior to the placement of a skin graft. Alternatively, a hinge flap in which a flap of fat adjacent to the defect is raised and turned over onto the defect can be used to cover exposed bone or cartilage and allow immediate graft placement.

Full-thickness skin grafts Technique An overview of how skin grafts are performed is shown in Figure 14-� 1.

Donor site selection Donor sites should be selected to match the ­recipient site as closely as possible with regard to color, texture, skin thickness, sebaceousness, and absence or presence of hair. There should be relative skin laxity at the donor site in which harvest scars can easily be hidden. The most common donor areas are the preauricular area, postauricular area, supraclavicular area, and the conchal bowl. In some instances, closure of a defect will require the excision of a redundant cone of tissue, which may be used as a graft. This is known as a Burow’s graft because it arises from a Burow’s triangle. Burow’s grafts provide a better texture and color match than more distant donor sites, and closure of the donor site is usually simpler.

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Dermatologic Surgery Table 14-1  The three stages of postoperative graft physiology after placement

Stage

Events

Imbibition

Ischemic period in which fibrin forms underneath the graft and keeps it attached. The graft relies on passive diffusion of nutrients from the graft bed

Inosculation

Dermal vessels in the graft become connected to vessels in the wound bed. During this phase, the graft becomes reperfused

Neovascularization

Capillaries grow into the graft from the graft bed. This phase may occur concurrently with inosculation. Lymphatic flow is re-established

Necrosis If an adequate vascular supply cannot be established, partial or full necrosis of the graft will occur. This is heralded by a black, thick, tightly adherent crust or eschar (Fig. 14-� 4a). It is best to leave the necrotic graft intact to act as a biological dressing and to provide a scaffold for regenerating tissue. The site should be dressed with petroleum jelly and covered to promote wound healing. In time, the eschar will fall off revealing pink viable tissue underneath (Fig. 14-� 4b).

Wound infection The development of wound infection at the graft site is rare but can occur if there has been a break in sterility, or may be due to seeding of the site in the postoperative period. It is characterized by edema, erythema, and purulence. Incision and drainage of abscesses, oral antibiotics directed at the causative organism, and conservative wound care should be carried out.

Postgraft cosmetic considerations Complications Hematoma Prior to placing a graft, meticulous hemostasis should be carried out to prevent the development of a hematoma underneath the graft. Although the development of a thin layer of fibrin beneath the graft is normal, the presence of a large ­hematoma inhibits diffusion of nutrients into the graft and limits the development of capillary ingrowth necessary for graft survival. Basting sutures and bolsters are employed to prevent hematoma formation. Basting sutures (Fig. 14-� 2) are sutures that attach the graft to the base of the recipient site. They may be placed percutaneously (going through the full thickness of the graft) or subcutaneously (intradermal bite on the graft side). They mechanically prevent a hematoma from forming underneath the graft. Bolsters (Fig. 14-� 3) are large cotton or gauze dressings that are sutured on top of the graft. They apply pressure to the graft and hold it flat against the recipient bed to maximize contact between the graft and the wound bed to prevent hematoma formation. More recently, thermo­ plastic bolster dressings have been described. The thermoplastic dressing is heated in a waterbath to 160°F so that it can be molded to fit the contours of the recipient site. Once it cools, it hardens and immobilizes the graft. It can be sutured or stapled to the recipient site for 5–7 days. Thermoplastic bolsters are most advantageous on convex or concave areas such as the nose and ear. However, they are more costly than traditional cotton bolster dressings.

Contraction Traditionally, it was thought that full-thickness skin grafts contracted minimally. However, one study showed that skin grafts contract by about 40% in the postoperative period. Infection of the graft was associated with a slightly greater degree of contraction (50%), presumably because part of the graft healed via secondary intention. Grafts on the nose and periorbital area contracted more than those on the scalp and temple. There did not seem to be an association between the degree of contraction and donor site, graft area, or patient age.

Pincushioning/scarring During the immediate postoperative period, grafts become edematous due to limited lymphatic drainage. This resolves with the re-establishment of lymphatic flow. Persistent elevation of the graft (Fig. 14-� 5) can be due to the development of a hypertrophic scar or pincushioning. Distinguishing between these possibilities can be difficult. A hypertrophic scar is characterized by a firm, smooth, elevated graft surface devoid of adnexal structures. Pincushioning occurs due to the formation of a plate-like scar beneath the graft that then contracts as the scar matures, pushing the center of the graft upwards. Wide undermining has been advocated to avoid pincushioning because the plate-like scar occurs over a greater area and is not confined solely to the area underlying the graft. Persistent graft elevation can be treated with dermabrasion, ablative resurfacing lasers, ­serial steroid injections, shave excision of fibrous tissue, or may spontaneously improve with scar maturation.

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Figure 14-1  Full-thickness skin graft. (a) Biopsy-proven basal cell carcinoma of the left ala prior to Mohs surgery. (b) Defect on the left nasal ala following Mohs micrographic surgery for a basal cell carcinoma. (c) A Gentian violet marker is used to mark the perimeter of the defect. (d) The reverse side of the suture cardboard label is pressed against the defect to create an imprint of the defect to serve as a template. Scissors are used to cut the template out. (e) The cardboard template is placed on the donor site and used to draw an appropriately sized ellipse. (f) A no. 15 Bard–Parker scalpel is used to excise the donor tissue. The deep surgical margin is shown to illustrate the yellow color of the adipose tissue, which must be removed. (g) Curved iris scissors are used to defat the graft. The graft is placed with the epidermis facing down. Curved scissors are used to remove the fat. Fat is relatively soft and easily removed by the scissors. The dermis is relatively tough and not easily cut by the scissors. (h) After the graft has been defatted, the white appearance of the dermis can be appreciated. (i) The donor tissue is laid onto the recipient site and positioned correctly. ( j ) Two simple interrupted sutures are placed at opposite ends of the graft to secure it in place. Curved scissors are then used to trim the graft to fit the recipient site exactly. (k) Simple interrupted sutures are placed to secure the graft in place. (l) Donor site repair with simple running suture

Pearls

Hyper/hypopigmentation Color mismatch may occur if the donor and ­recipient tissue have different degrees of actinic damage. Superficial dermabrasion, dermasanding, Erbium or carbon dioxide resurfacing can result in a better color match when performed as early as 6–8 weeks postgraft. However, these procedures require additional wound care.

• For grafts on the nose, place basting sutures oriented along the alar groove to help recreate it (see Fig. 14-������ 2����� ). • If pleats develop along the circumference of the graft, the graft is oversized and needs to be trimmed down to size. • Some surgeons prefer to harvest the graft using a 45° bevel, to match the bevel of the recipient site following Mohs micrographic surgery.

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Split-thickness grafts Indications Split-thickness skin grafts are useful to cover large defects and are more likely to take than fullthickness grafts. Fenestrating or meshing the graft

allows it to cover an even larger area while enabling blood and serum to drain from beneath the graft. For aggressive tumors and tumors with a high chance of local recurrence, split-thickness grafts are particularly useful because tumor recurrence can be easily observed due to the thinness of the graft.

Contraindications Split-thickness grafts have a poorer cosmetic outcome than full-thickness grafts in terms of texture, color, and skin thickness. Contraction of the recipient site is greater for split-thickness grafts and, therefore, should be used with caution near free margins. Specialized equipment is necessary and creates a donor site that heals by secondary intention.

Donor site selection

Figure 14-2  Basting sutures help to secure the graft to the wound bed and prevent shearing forces from disrupting the graft–host interface

Donor sites heal by secondary intention and usually appear hypopigmented. Sites that are nonexposed and easily accessible to the patient for wound care tend to be favored, such as the upper thigh, lateral hips, medial arms, lower back, and abdomen.

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Figure 14-3  Bolsters. (a) Full-thickness skin graft after placement. (b) Simple interrupted sutures are placed around the perimeter of the graft. One end of the suture is cut short and the other end is left long. (c) Gauze impregnated with petroleum jelly is placed over the graft to keep it moist. (d) The long ends of the suture are tied to one another to secure the bolster

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Figure 14-4  Necrosis. (a) Necrosis is characterized by a black, thick, tightly adherent crust or eschar. (b) It is best to leave the necrotic graft intact to act as a biological dressing. With conservative wound care, the eschar will fall off, revealing pink viable tissue underneath

Complications Split-thickness grafts are subject to many of the same complications that may occur with fullthickness grafts. Hematoma and seroma forma­ tion can be avoided by meshing the graft in addition to tacking sutures or bolster dressings. Owing to the decreased nutritional requirements, split-thickness grafts are less likely to undergo necrosis than full-thickness grafts. Split-thickness grafts are not as durable and tend to develop ulcers in areas of mechanical trauma. Pain at the donor site is common and may be ameliorated with occlusive dressings. Figure 14-5  Persistent elevation of the graft may be due to the development of a hypertrophic scar or pincushioning

Composite grafts

Technique (Fig. 14-� 6)

Composite grafts are used to replace defects that are missing both cartilage and skin, such as fullthickness loss of the alar rim. These grafts require revascularization from the graft’s edge and thus are usually small in size (less than 1 cm).

Free-hand grafts

Donor site selection

A no. 10 or 15 blade can be used to harvest small split-thickness grafts by hand. Alternatively, a Weck blade, which is a long straight blade, may be used to obtain larger split-thickness grafts by hand. Free-hand grafts can be performed quickly and do not require the use of specialized ­equipment.

The cartilage and skin of the ear is most often used to repair nasal defects. Donor sites are selected so that the harvested graft matches the missing nasal tissue as closely as possible. The crus or the helical rim is most commonly used to reconstruct the ala. The conchal cartilage is most commonly used to repair the nasal sidewall or columella.

Dermatome grafts Powered dermatomes (driven electrically or pneumatically) can be used to harvest larger splitthickness grafts and allow the harvesting of grafts with consistent thickness. Graft thickness can be selected by means of a lever on the dermatome. Most grafts of the head and neck are 0.012– 0.016 inches thick. For recipient sites on the trunk and extremities, grafts of 0.020–0.024 inches are used.

Technique (Fig. 14-7) First, the recipient site must be made smooth so that the planned graft may fit in precisely. Because revascularization from the sides is mandatory for graft survival, it is critical that a template of the wound be drawn and then transferred to the selected donor site. The template should be slightly oversized to account for postoperative

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Dermatologic Surgery

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Figure 14-6  Split-thickness skin graft. (a) This patient presented with a large morpheaform basal cell carcinoma on the right cheek. (b) There is a large defect on the cheek following Mohs surgery. (c) A template on the right thigh is drawn for the split-thickness skin graft. The graft taken may be smaller than the recipient site if meshing will be performed. Hair within the template is shaved and a drop of mineral oil is applied to the donor site to facilitate the harvest. (d) An electrically powered dermatome is used to harvest the graft using firm, steady, downward pressure on the device. (e) Donor site after harvesting of the graft. Note the pinpoint bleeding. The donor site is allowed to heal by secondary intention. (f) The split-thickness graft is put in a Petri dish with normal saline to keep it moist. (g) The graft has been put through a mesher to increase its size and placed over the wound bed. Absorbable sutures may be placed to secure the graft to the recipient bed. (h) The graft 4 days after placement. (i) Some 2.5 months later, the graft has fully healed

contra­ction. The graft may be designed with wings or struts that extend beyond the cutaneous portion and fit into grooves at the recipient site for additional mechanical security. If cartilaginous wings are used, then a scalpel should be used to incise a groove or pocket in the tissue adjacent to the recipient site into which the struts of the composite graft may be placed. Sutures are placed to secure the graft to the mucosal surface of the nose first. This secures and

aligns the graft at the recipient site. The cartilaginous struts are placed into the pockets created previously. Sutures are placed around the perimeter to secure the graft. Intranasal packing is placed followed by petroleum jelly and gauze externally.

Complications Composite grafts are subject to necrosis due to inadequate revascularization. This is a particular problem in smokers.

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14

e Figure 14–7  Composite graft. (a) Nasal ala defect following Mohs surgery for basal cell carcinoma. (b) Donor site of composite graft at crus of helix drawn approximately 10% larger than the defect. (c) Donor site following excision of composite graft. (d) Underside of helical composite graft illustrating cartilage on left side of graft, which will provide support to the alar rim. (e) Composite graft sutured into place with petrolatum-coated dental roll in nostril

Further reading Adams DC, Ramsey ML. Grafts in dermatologic surgery: review and update on full- and split­thickness skin grafts, free cartilage grafts, and composite grafts. Dermatol Surg 2005;31(8 Pt 2): 1055–1067.

Christensen DR, Arpey CJ, Whitaker DC. Skin grafting. In: Robinson JK, Hanke CW, Sengelmann RD, Siegel DM, eds. Surgery of the Skin. New York: Elsevier Mosby, 2005:365–379. Fader DJ, Wang TS, Johnson TM. Nasal reconstruction utilizing a muscle hinge flap with overlying full-thickness skin graft. J Am Acad Dermatol 2000;43(5 Pt 1):837–840.

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Dermatologic Surgery Geyer AS, Pasternack F, Adams C, Ratner D. Use of a skin–fat composite graft to prevent alar notching: an alternative to delayed postoperative repair. Dermatol Surg 2005;31(5):602–607. Gloster HM Jr. The use of full-thickness skin grafts to repair nonperforating nasal defects. J Am Acad Dermatol 2000;42(6):1041–1050. Gurunluoglu R, Shafighi M, Gardetto A, Piza-Katzer H. Composite skin grafts for basal cell carcinoma defects of the nose. Aesthetic Plast Surg 2003;27(4): 286–292. Meads SB, Greenway HT, Eaton JS. Surgical pearl: thermoplastic bolster dressing for full-thickness skin grafts. J Am Acad Dermatol 2006;54(1): 152–153.

Shook BA, Peterson J, Wells MJ, Butler DF. The beveled edge technique for harvesting of fullthickness skin grafts. Dermatol Surg 2005;31(9 Pt 1):1128–1130. Silapunt S, Peterson SR, Alam M, Goldberg LH. Clinical appearance of full-thickness skin grafts of the nose. Dermatol Surg 2005;31(2):177–183. Stephenson AJ, Griffiths RW, La Hausse-Brown TP. Patterns of contraction in human full thickness skin grafts. Br J Plast Surg 2000;53(5):397–402.

Elizabeth Magill Billingsley

Key Points • Nail surgery can be relatively painless when performed properly.

• Patient relaxation is important for nail surgery to run smoothly.

• It is important to discuss the risk of permanent

nail dystrophy and obtain informed consent prior to the procedure. • Avoid unnecessary trauma to the proximal nail matrix to minimize the chance of permanent nail dystrophy. • Perform biopsies no larger than 3 mm if possible. • Orient excisions in the nail matrix transversely, and excisions in the nail bed longitudinally for optimal results. • The distal matrix produces the undersurface of the nail plate. Small wounds in this area are unlikely to produce a visible nail defect. • The proximal matrix produces the dorsal surface of the nail plate. Large wounds in this area have the greatest potential to produce a visible nail defect. • Explain postoperative instructions clearly.

Introduction Surgical procedures involving the nail unit may be necessary to diagnose inflammatory disorders or neoplasms. They may also be therapeutic, as when removing a growth or relieving the discomfort of an ingrown nail. Many nail procedures, such as avulsions, matrixectomy, and biopsies, can be simple to perform in an office setting. With experience, they can be performed quickly, and planned so as to minimize the risk of permanent nail dystrophy (Box 15-� 1).

Anatomy Before undertaking any nail procedure, it is ­important to have a thorough understanding of nail unit anatomy (Fig. 15-� 1). The most important structure in the nail unit is the nail matrix. The matrix is the germinative epithelium from which the nail plate is generated. The distal nail matrix, often visible through

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the proximal nail plate, is called the lunula. The proximal matrix forms the dorsal surface of the nail plate, and the distal matrix is responsible for the ventral portion, or underside, of the plate. This anatomic concept is important when performing nail unit surgery because damage to the proximal matrix is likely to produce a visible permanent nail dystrophy. This is in contrast to surgery of the distal matrix, which may produce a nail deformity that is not visible because it is on the undersurface of the nail plate. The nail bed, sometimes called the sterile matrix, extends from the lunula to the hyponychium. The hyponychium is the end of the nail bed and the beginning of the normal volar epidermis. The proximal and lateral nail folds surround and support the nail plate. The cuticle is the distal extension of the proximal nail fold, and serves to seal and protect the proximal nail fold from external pathogens and irritants. The vascular supply to the nail unit and distal digit is derived from the paired proper palmar and plantar arteries. These arteries travel along the lateral aspects of the digit, and form a series of arcades supplying blood to the proximal nail fold, matrix, nail bed, and end of the digit. The paired palmar and plantar nerves run in close apposition to the blood vessels, along the lateral aspects of the digit. The extensor tendon of the digit is an important anatomic structure. This tendon attaches in a broad distribution approximately 12 mm proximal to the proximal nail fold. Extensive damage to this tendon attachment, either with a ­surgical B ox 1 5 - 1

Keys to successful nail surgery • Patient relaxation – calm atmosphere, positioning • Communication – expectations of the procedure and post­ operative period • Painless anesthesia (relatively!) and painless procedure • Proper instruments • Appropriate knowledge of nail anatomy and surgical technique

190

Dermatologic Surgery Proximal nail fold Cuticle Lateral nail fold Nail plate

Hyponychium

Bone

Nail matrix

Nail bed

Figure 15-1  Nail unit anatomy

instrument or through excessive heat with ­cautery or laser, could result in difficulty with full extension of the tip of the digit.

Preoperative considerations As with any surgical procedure, a thorough medical history should be obtained prior to performing nail surgery. Although not absolute ­contraindications to surgery, a history of peripheral vascular disease, collagen vascular disease, diabetes, or a bleeding disorder should be noted. Prophylactic antibiotics may be indicated in ­ patients who have artificial heart valves or other risk factors for endocarditis. The patient’s medications should be reviewed, with specific attention to anticoagulants. Patients on aspirin, warfarin, clopidogrel, and certain supplements may have increased operative and postoperative bleeding, and will need extra attention paid to hemostasis. Allergies to medications should be recorded. Photographs should be taken preoperatively, especially for pigmented streaks, neoplasms, and where there is significant risk of permanent nail dystrophy. These photos could be helpful in a medicolegal situation to document the location of the lesion and the need for the procedure to be performed. Photos are also very helpful for teaching purposes. When there is suspicion that there may be an underlying bony process, such as a subungual exostosis, or invasive malignancy, radiographs are helpful to delineate the extent of the neoplasm. Prior to the procedure, it is extremely important to spend time in consultation with the patient explaining the procedure, expectations of pain, and postoperative limitations. Risk of permanent nail dystrophy should also be explained fully and informed consent should be obtained. Patients generally have many questions, and time spent

a­ ddressing these concerns prior to undergoing the procedure is extremely beneficial (Box 15-� 2).

Anesthesia Perhaps the most anxiety-provoking aspect of nail surgery is the patient’s fear of pain from administration of the local anesthetic. Nail surgery can be performed with significantly less anxiety when attention is focused on minimizing the discomfort of this part of the procedure. Patient relaxation is very important to lessen the real and perceived discomfort of the injection. Placing the patient in a supine position and creating a relaxed atmosphere in the surgical room, through a reassuring and confident staff, can help to calm an anxious patient. Music can also be helpful. A digital nerve block is an excellent means of decreasing the pain of achieving anesthesia in the distal nail unit. This is far less painful than ­injecting directly into the nail unit. As small volumes of anesthetic are needed for this procedure, 2% plain lidocaine is an excellent choice of anesthetic. If prolonged anesthesia is required, supplemental 0.25% bupivacaine can be also be used. Recent literature has suggested the use of epinephrine in digital blocks is generally safe, and may be helpful for minimizing operative bleeding, but should be avoided in patients with peripheral vascular disease. To perform the digital nerve block, a 30gauge needle is placed at the midline of the medial and lateral aspects of the base of the digit. An initial small bleb of anesthetic is in2). Addijected very ­ superficially (Fig. 15-� tional anesthetic is administered slowly, while advancing the needle deep in the skin toward the bone. The needle is then withdrawn slightly and advanced toward the dorsal and then volar aspects of the digit. It is important that the needle is advanced in a linear fashion and that

Chapter

Nail surgery

15

B ox 1 5 - 2

Preoperative considerations • Medications: anticoagulants • Allergies • Medical history: peripheral vascular disease, diabetes, bleed­ ing diathesis, prosthetic valves, collagen vascular disease • Photos or digital images • X-rays: subungual exostosis, enchondroma, tumor with bony invasion • Counseling: expectations of discomfort, time for nail regrowth, postoperative footwear, possible difficulty with work • Consent: risk of permanent nail dystrophy

Figure 15-3  Digital block in web space

Figure 15-2  Digital block at base of thumb

Figure 15-4  Wing block of thumb

great care is taken to avoid any lateral motion, which may cause laceration of the digital neurovascular bundle. ­ Approximately 1.0–1.5 mL of anesthetic on each side of the digit should be adequate, Another approach that may produce even less discomfort is to inject the lidocaine into the adjacent web space to access a more proximal aspect of the nerve (Fig. 15-� 3). It is very important to allow enough time for the anesthesia to take effect. Usually 10–15 min is sufficient. Sensation of the distal digit should then be assessed. If the patient still has sensation, the options include allowing more time for the block to become fully effective, or adding supplemental anesthetic in a wing block fashion. A wing block is accomplished by injecting a small amount of anesthetic at the junction of the proximal and lateral nail folds (Fig. 154). The needle is advanced slightly toward the tip of the digit, and then across the proximal nail fold. Many surgeons choose the wing block as the preferred method for anesthesia of the digit.

Surgical instruments The instruments needed on a surgical tray for a nail procedure will be determined by the procedure being performed (Fig. 15-� 5). The Freer ­septum elevator is very useful for nail avulsions, and the English nail splitter is important for ­partial nail avulsions. Other instruments that are often used are listed in Box 15-� 3.

Hemostasis Hemostasis during nail surgery may be obtained by a variety of means. Electrocautery is effective for spot hemostasis during biopsies and along lateral nail fold incisions. Gel foam and pressure may be useful for punch biopsies or on an oozing wound. Aluminum chloride may also be useful, especially on the nail bed. Lateral compression of the digital artery by a surgical assistant is very effective in minimizing bleeding during the procedure. For larger procedures, and ones where a very dry field is necessary, a clamped Penrose drain can

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Hemostasis • Cautery • Penrose drain • Gel foam • Aluminum chloride • Pressure, lateral compression

Figure 15-5  Surgical tray for nail procedures. From left to right – bottom: English nail splitter, Freer septum elevator, hook, hemostat, curette, nail-pulling forceps, penrose drain; top: gauze, scalpel, marker, urethral swabs, phenol

B ox 1 5 - 3

Surgical instruments • Freer septum elevator or nail spatula • English nail splitter • Hemostat • Nail-pulling forceps • Scalpel • Marker • Penrose drain • Miscellaneous: curette, punch biopsy, forceps, scissors

serve effectively as a tourniquet. ­Another option for hemostasis is placing a sterile glove on the patient’s hand with the glove fingertip cut off and rolling it back on itself to the base of the digit (Box 15-� 4).

Procedures Nail avulsion Nail avulsion is the most basic nail surgical procedure and may involve partial or complete removal of the nail plate. Avulsions are often performed to allow visualization of the underlying nail unit for biopsy or excision. Partial or complete avulsions may also be performed to improve discomfort of an ingrown nail, or allow drainage of a paronychia. The basic surgical concept of an avulsion is to ­remove the nail plate from its attachments to the nail bed, nail matrix, and surrounding nail folds.

Distal nail avulsion After cleansing the hand or foot with surgical antiseptic scrub, a digital block or wing block is performed. Once adequate anesthesia is obtained,

Figure 15-6  Freer septum elevator being used to separate nail plate from nail bed

a Freer septum elevator or dental spatula is used to separate the distal end of the nail plate from the nail bed (Fig. 15-� 6). The instrument is pushed firmly in a proximal direction, aiming it upwards toward the nail plate to avoid injury to the underlying nail bed. The instrument is then removed and reinserted multiple times, gradually advancing proximally until the matrix is reached, identified by a marked decrease in resistance. Care must be taken to avoid damaging this area of the nail unit with aggressive pushing. After the nail plate has been separated from the nail bed and the surrounding nail folds, a hemostat or nail-pulling forceps may be used to gently remove the nail, either in a rolling side-to-side motion or with a direct pulling motion (Fig. 15-� 7). After the nail is removed, hemostasis can usually be accomplished with direct pressure (Box 15-� 5). If that is inadequate, spot electro­cautery or aluminum chloride may be used.

Proximal nail avulsion Nail avulsion via a proximal approach may be necessary when there is significant distal subungual debris or damage, or if there is no distal free nail edge. In these cases, the instrument is inserted beneath the proximal nail fold, and aimed proximally until it reaches the beginning of the nail plate. It is then rotated under the nail plate, and advanced distally, gently separating the nail matrix and nail bed from the plate (Figs 15-8 & 15-9).

a

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b

Figure 15-7  Nail avulsion performed by (a) direct pulling motion or (b) rolling the nail plate, assuring removal of lateral aspects of nail

Figure 15-8  Proximal nail avulsion using Freer septum elevator

B ox 1 5 - 5

Nail avulsion • Clean procedure • Digital block • Insert nail spatula or Freer septum elevator under distal free edge of nail • Gently push instrument proximally, avoiding damage to the nail bed and matrix • Remove and reinsert several times until plate is free from bed and nail folds • Remove nail plate in rolling or pulling motion

Figure 15-9  Freer septum elevator gently separating nail plate from nail bed in proximal approach

Nail matrixectomy Matrixectomy is performed when the goal is permanently to remove all or part of the nail, and prohibit further nail growth. The most common indication for this is recalcitrant ingrown nails (onychocryptosis), but this procedure may also be performed for other reasons, such as deformed nails or fungal disease. Matrixectomy may be achieved by excision or ablation. Excisional techniques include cold steel, electrosurgery, or laser. More commonly, ablative techniques that achieve chemical destruction of the matrix are performed. The most common chemical used for this purpose is phenol (88% carbolic acid),

193

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Dermatologic Surgery which must be kept in a dark bottle, and must not have exceeded its expiration date (Box 15-� 6).

Partial matrixectomy Partial matrixectomy destroys the lateral aspect of the nail matrix, and allows the central portion of the nail to remain for cosmetic and functional importance. Phenol matrixectomy is performed as a clean, but not sterile, procedure. After a digital block is performed, an English nail splitter is used to make an incision approximately 2–4 mm from the lateral edge of the nail. The incision is advanced proximally, by gently inserting the blunt end of the splitter underneath the proximal nail fold until the proximal aspect of the nail plate is cut (Fig. 15-10). Next, the Freer septum elevator is used gently to separate the nail plate from the nail bed in this area, and this portion of the nail plate is then removed. Care should be taken to ensure that the most proximal and lateral aspects of nail in the proximal groove are included. The next step is the destruction of the matrix. A bloodless field is necessary as blood minimizes the effectiveness of phenol. Once this is achieved, a cotton-tipped applicator is then saturated with B ox 1 5 - 6

Nail matrixectomy using phenol • Clean procedure • Partial or complete nail avulsion • Obtain a bloodless field • Apply phenol with small cotton swab or urethral swab to proximal matrix • Apply to deep corners for partial matrixectomy, to entire matrix for complete matrixectomy • Rinse with alcohol or saline after 30–60 s • Repeat phenol application and rinse again

Figure 15-10  English nail splitter being used to incise lateral portion of nail plate

phenol solution. It is inserted underneath the nail fold and advanced onto the lateral corner of the matrix. It is important that the swab reaches the most proximal and lateral horns of the matrix to prevent regrowth of nail spicules. Urethral swabs, which are smaller than most cotton-tipped applicators, can be more effective in reaching underneath the nail fold and limiting any inadvertent contact with the nail fold (Fig. 15-11). Petrolatum may be placed along the nail folds to prevent damage to the surrounding skin. The phenol is left in place for 30–60 s and rinsed with alcohol or saline. This procedure is then repeated. A curette may be helpful to remove any granulation tissue along the nail folds or any residual necrotic tissue in the treated area. Corticosteroid injected into the proximal and lateral nail fold helps to minimize postoperative discomfort. Triamcinolone, 5 mg/mL is often used. Phenol is an effective coagulant, and has antiseptic as well as local anesthetic properties. Chemical matrixectomy can also be performed using 10% sodium hydroxide, applied for 1 min, and then neutralized with 10% acetic acid.

Complete matrixectomy Complete matrixectomy is performed when the goal is permanent removal of the entire nail plate. A complete nail avulsion is performed, followed by application of phenol to the entire nail matrix. Electrodessication and curettage, electrosurgery, laser, and surgical excision are other approaches for complete matrixectomy.

Nail unit biopsy Biopsy of the nail unit may be necessary to diagnose a dermatosis, such as psoriasis, a tumor such as squamous cell carcinoma, or to determine the cause of a pigmented streak. The biopsy may be done via a punch through the nail plate, or after nail avulsion. Nail matrix and nail bed lie in close proximity to periosteum, and these procedures should be performed using sterile technique to

Figure 15-11  Urethral swab saturated in phenol, prior to placing underneath nail fold

prevent osteomyelitis. Also, great care should be taken to handle the biopsy specimen carefully, as crushing the tissue can produce artifact making histologic interpretation much more difficult.

Biopsy of pigmented streak Pigmented streaks should be biopsied at the most proximal aspect of the streak. If the origin of the streak is visible through the nail plate, a punch ­biopsy may be adequate for diagnosis. This is most easily done with a larger punch, such as a 4 or 5 mm, to remove the overlying nail plate, followed by a 3-mm punch to remove the designated nail bed or matrix. Ink placed on the superficial surface of the biopsy can aid in specimen orientation for proper embedding. If the origin of the pigmented streak is proximal to the lunula, the proximal nail fold may need to be reflected. This is accomplished by making two 5-mm releasing incisions at the junction of the proximal and lateral nail folds. These should extend at an angle towards the lateral aspects of the digit. The proximal nail fold is then reflected back, and held in place with retaining sutures that can be secured with a hemostat, or by using a skin hook. The proximal matrix should then be visible. A single punch may be used for both the thin proximal nail plate and the underlying tissue (Fig. 15-12). Complete nail avulsion may be performed to facilitate a biopsy and allows the entire nail unit to be examined. Avulsion is also often necessary for complete removal of tumors, or to obtain a shave biopsy of the nail unit. It is very helpful to ink the proximal nail fold in line with the area to be biopsied prior to avulsing the nail, as biopsy

Figure 15-12  Punch biopsy of matrix after reflecting proximal nail fold. Note ink on proximal nail fold indicating location of streak

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location may become difficult to identify once the nail plate is removed. To visualize the entire matrix after nail avulsion, it may be necessary to reflect back the proximal nail fold, as described above (Fig. 15-13). A shave or saucerization can be used to remove the lesion in question.

Nail matrix biopsy When possible, biopsies of the nail matrix should be performed in the distal matrix to minimize visible permanent nail dystrophy. Ideally, punch biopsies should be 3 mm or less, and these small biopsies do not need to be sutured in the mid and distal matrix. Biopsies 3 mm or larger in the proximal matrix should be sutured to minimize the potential for nail dystrophy. Another technique for sampling matrix tissue is the shave biopsy. Shave biopsies can be performed for larger lesions and for lesions in the proximal matrix. This method has less risk for causing permanent nail dystrophy. ­Elliptical excisions of the nail matrix should be oriented transversely, and with careful undermining of the matrix, may be sutured with an absorbable or nylon suture. This would result in a uniformly thinner nail rather than a longitudinal split. It is important not to interfere with the curvilinear distal border of the lunula in order to prevent distal onycholysis and abnormal curvature of the distal free nail edge (Box 15-� 7).

Nail bed biopsy Punch biopsies of the nail bed that are 3 mm or less do not need to be sutured. Elliptical excisions of lesions, such as a glomus tumor, should be oriented longitudinally, and with careful undermining above the periosteum they may be sutured to minimize the risk of onycholysis.

Figure 15-13  Reflection of proximal nail fold using skin hook, revealing matrix lesion

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En bloc excision Longitudinal resection or wedge resection involves the removal en bloc of nail folds, nail plate, nail bed, matrix, and hyponychium. This may be necessary to help with diagnosis of ­lateral ­longitudinal pigmented bands and for some inflammatory conditions that involve many parts of the nail unit. It is performed by making an excision through the proximal nail fold, matrix, nail plate and nail bed, and through the lateral nail fold on the other side (Fig. 15-14). The specimen is removed en bloc, and the wound is sutured or allowed to granulate (Fig. 15-15). Lesions arising in or underneath the proximal nail fold, such as mucous cysts, can produce significant nail dystrophy due to pressure on the underlying matrix. These lesions can be excised by reflecting back the proximal nail fold and removing the lesion, or by an en bloc excision of the proximal nail fold. These en bloc excisions should be symmetric across the width of the digit to allow for aesthetic healing, and are allowed to heal by second intention. Significant care must be taken not to damage the underlying matrix. A Freer septum elevator placed underneath the proximal nail fold can protect the matrix from inadvertent damage (Fig. 15-16). B ox 1 5 - 7

Nail matrix biopsy • Sterile procedure • May be performed through the nail plate or after nail avulsion • 3 mm or smaller punch if possible • Distal matrix rather than proximal matrix if possible • Elliptical biopsies should be oriented transversely, under­ mined, and sutured

Figure 15-14  En bloc excision of lateral nail fold, including hyponychium, nail plate, nail bed, matrix, and proximal nail fold

Postoperative management Immediately after the procedure, the area should be cleansed and dried. It is helpful to hold direct compression for a few minutes to ­ensure hemostasis. The bandage should be absorbent, nonadherent, bulky, and nonconstrictive. An initial layer of petroleum jelly should be used to protect the wound bed. Vaseline-impregnated gauze is also useful. The next layer consists of nonadherent gauze, followed by an additional layer of gauze for absorption and protection. The securing layer must hold the bandage in place but not be constrictive, and can be a metal frame or tape. For toe-nail surgery, an open-toed shoe may improve comfort. Patients need to be educated about their ­expectations of postoperative pain and possible limitations in activities. Nail surgical patients may or may not experience significant pain. Postoperative pain management should consist initially of elevation of the affected area and administration of acetaminophen or nonsteroidal anti­inflammatory agents (NSAIDs). If pain is not adequately managed with these interventions, a prescription pain medication may be needed. A prescription sent home with the patient with instructions to fill only if needed can be helpful. Also, taking acetaminophen or NSAIDs before the local anesthetic has worn off, and on a regular schedule in the first 24–48 h, may minimize any postoperative pain. After 24 h, the initial bandage may be removed. The wound should be cleansed once or twice daily with soapy water, gently loosening any debris. Soaking may be helpful to loosen an adherent bandage or debris, or if there is much swelling. The new bandage should be nonadherent, absorbent, protective, and secure. Petroleum

Figure 15-15  Sutured wound after en bloc excision of lateral nail fold lesion

Figure 15-16  En bloc removal of proximal nail fold mucous cyst. Note Freer septum elevator being used to protect underlying matrix

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Postoperative considerations • Wound care – written and verbal instructions, bandaging • Elevation • Pain management – acetaminophen, ibuprofen, narcotics • Soak wound – swelling, debris

jelly and an adhesive bandage may be sufficient for the fingers, but an additional layer of gauze may be necessary on a toe, to help cushion as well as absorb drainage (Box 15-� 8).

Complications As with all surgical procedures, complications such as bleeding, infection, and pain may occur. Antibiotics are not given routinely in nail surgery, and an appropriate antibiotic should be prescribed only when there is a culture-proven infection. Osteomyelitis and septic arthritis can occur, but fortunately, with proper surgical technique, these

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complications are rare. There are reports in the literature of pyogenic granuloma formation and reflex sympathetic dystrophy occurring following nail surgery. The most important complication of nail surgery is permanent nail dystrophy. In most cases, this can be anticipated, discussed with the patient preoperatively, and, with surgical attentiveness, minimized.

Pearls Nail surgery pearls Take preoperative photos Good patient counseling Use a marker for biopsies prior to removing the nail plate DON’T CRUSH THE SPECIMEN Orient matrix biopsies transversely, nail bed biopsies longitudinally When possible, biopsy the distal matrix rather than the proximal matrix

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Justin G. Woodhouse and Allison T. Vidimos

Key Points • Mohs micrographic surgery is a specialized

surgical technique for skin tumor extirpation.

• Mohs surgery incorporates horizontal frozen-

section processing and specialized mapping to enable evaluation of the entire excised surgical margin. • For neoplasms of the skin that grow in continuity, Mohs surgery offers the highest cure rate while minimizing the amount of normal skin sacrificed for tumor removal. • Mohs surgery requires specialized training in cutaneous tumor biology, surgical technique, histopathologic interpretation, and subsequent reconstruction. • The success of Mohs surgery is predicated on the concept of continuous tumor spread from a single focus, and is also dependent on the resources and skills of the surgeon and histotechnician. • When used for the proper indications, Mohs surgery is cost effective, but generally more expensive and labor intensive than conventional methods of tumor removal. • With proper technique and preoperative preparation, Mohs surgery has an exceedingly low complication rate.

History Mohs micrographic surgery was initially conceptualized by Dr Frederic Mohs at the University of Wisconsin in the 1930s when he began to use zinc chloride paste for fixation of tissue in vivo. Zinc chloride has been used as an escharotic treatment of cancer since the 1800s but Mohs incorporated microscopic examination of tissue at the time of tumor removal. Subsequently, the need for additional marginal tissue could be determined while the patient was still in the office. Using a special method of tissue processing, he devised a way to evaluate 100% of excised surgical margins. Subsequently, Stegman and Tromovitch modified the technique and used the currently preferred method of fresh tissue processing, without the

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use of zinc chloride paste . The ­American College of Mohs Micrographic Surgery and ­ Cutaneous ­Oncology was established in 1967 and currently has nearly 800 members, all of whom have received advanced fellowship training in Mohs surgery, pathology, and reconstructive surgery.

Skin cancer treatment overview Skin cancer is a general term for any tumor developing from the cutaneous structures within the epidermis, dermis, or subcutaneous tissue immediately deep to the dermis. There are more than two dozen distinct tumors that arise from specific cell types within any of these tissue planes. Basal cell carcinoma (BCC) is the most common skin cancer, and squamous cell carcinoma (SCC) is the second most common. Many treatment modalities have been devised for the elimination of skin cancer. The most commonly used skin cancer treatments include simple excision, electrodessication and curettage, cryosurgery, radiation therapy, topical chemotherapy, and Mohs micrographic surgery. Many variables should be taken into consideration when choosing the most optimal therapy for any given patient (Box 16-� 1). Certainly, the ultimate success of any given modality is predicated on the skill and experience of the physician, but approximate cure rates for each modality are listed in Table 16-1. In general, all non-Mohs surgery modalities result in lower cure rates when employed for tumors on the head versus the trunk or extremities.

Mohs concepts The two main advantages of Mohs surgery are (1) histologic confirmation of tumor removal with a very high cure rate, and (2) normal tissue preservation. In all cases, the most important primary goal is eradication of the tumor. Regardless of the final cosmetic outcome, tumor recurrence

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Important factors influencing treatment modalities for skin cancer Treatment factors Physician skill and competence Cure rate inherent to treatment Morbidity Cost and access Cosmetic outcome Effect on/preservation of local anatomic structures vs other modalities Patient factors General health and co-morbid conditions (immunosuppression, diabetes, hypertension) Patient support system and wound care needs Age and life expectancy Cosmetic concerns Disease factors Tumor type and subtype Anatomic location Size Presence or absence of perineural invasion Growth pattern Primary vs. recurrent Prior irradiation of area

Table 16-1  Cure rates for different skin cancer treatment modalities

5-year cure rate (%) BCC

SCC

Surgical excision

89.9

91.9

Cryotherapy

92.5

NA

Electrodessication and curettage

92.3

96.3

Radiotherapy

91.3

90.0

Mohs surgery

99.0

96.9

NA, not applicable. Source: Rowe DE, Carroll RJ, Day CL J Dermatol Surg Oncol 1989;15:315–328 & J Am Acad Dermatol 1992;26:976–990.

­ bviates success. Accordingly, tumor extirpation o via Mohs surgery requires meticulous, precise surgical incisions and tissue markings to minimize the possibility of error in the processing stage of the operation. Likewise, timely and careful mounting, sectioning, and staining by the Mohs laboratory histotechnician is paramount to cure and operational success.

The outstanding cure rate offered by Mohs surgery is due to the meticulous evaluation of 100% of the excised surgical margins. This same aspect of Mohs surgery allows the surgeon to cut in very close proximity to the perceived margin of the tumor. This will inherently lead to maximal tissue preservation, which is the secondary goal of Mohs surgery. Oftentimes, the tumor is relatively well demarcated and this approach permits a very small postoperative defect without sacrificing overall cure rates. On the other hand, aggressive or recurrent tumors are better likened to an iceberg with a substantial imperceptible tumor burden tracking under the surface of the skin. In this instance, the microscope helps to guide the surgeon in determining where additional tumorladen skin needs to be removed. In each case, the surgery is designed to remove only cancerous skin and thus spares normal skin, inherently maximizing cosmetic outcome and the function of local anatomic structures. The relative importance of tissue preservation changes somewhat for any given patient and tumor location. For example, tissue preservation on the cheek of an 87-year-old man with a multiply recurrent infiltrative BCC is less important than in a 43-year-old woman with a primary BCC on the cheek. In the case of the elderly man, the value of Mohs over wide excision is margin control and ultimate cure rate. Figure 16-� 1 depicts a tumor with finger-like infiltrative extensions of cancer under the surface of the skin. The initial saucerized portion of skin is removed and the skin edges and undersurface of the skin are evaluated. The tumor is found in the deeper dermis in one of the quadrants and a subsequent specimen is taken in that area to clear the tumor. Mohs micrographic surgery has several indi­ cations, which are listed in Box 16-� 2. From a practical standpoint, the indications are situations where other modalities are much more likely to lead to recurrence, increased morbidity and eventually increased cost. Several publications have validated the cost-effectiveness of Mohs surgery when used for appropriate indic­ations. Mohs is most commonly used for cutaneous neoplasms on the face, and is particularly important in the H zone of the face (Fig. 16-� 2). In these areas, tumors have higher recurrence rates and are often more aggressive and invasive. This is likely due in part to the relative ease of invasion through natural embryonic fusion planes. Many different cutaneous tumors can be removed via Mohs surgery and these are listed in Box 16-� 3. By far the most common tumor is BCC, followed by SCC. Some of the tumors listed are more commonly treated with other methods, or the use of Mohs surgery is controversial. In the case of rare tumors, it is most beneficial for the

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Figure 16-1  The tumor is removed in a saucer-shaped section and divided into pieces for processing. Evaluation of all excised margins reveals skin cancer present at one of the dermal edges of excision. This area is subsequently excised to remove the rest of the tumor

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Indications for Mohs surgery • Facial tumors, particularly in H zone, lips, eyelids, ears • Recurrent tumors • Tumors 1 cm or greater on the neck or face • Aggressive pathology on hands, feet, genitals • Tumors 2 cm or greater in areas other than face • Positive margins on recent excision • Poorly defined borders obviating margin control • Radiation-induced tumors

Highest

Intermediate

Lowest

Figure 16-2  “H zone” of the face indicating areas of particular recurrence risk

• Tumors with perineural invasion on biopsy • Deeply infiltrating tumors exhibiting difficulty in estimating tumor depth • Tumor occurring in an old scar or wound (Marjolin’s ulcer) • Tumor in a patient with basal cell nevus syndrome • Tumor in a patient with xeroderma pigmentosa • Tumor in patients with proven difficulty with skin cancer – immunocompromised or organ transplant patients

patient to be treated at a center with more experience of treating that particular type of cancer.

Mohs preoperative evaluation Prior to surgery, several factors are important to address for optimal outcomes. Once Mohs surgery has been deemed appropriate for the given tumor

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Tumors potentially treated with Mohs surgery

Preoperative evaluation

• Basal cell carcinoma (BCC) • Squamous cell carcinoma (SCC) • Lentigo maligna (LM) • Dermatofibrosarcoma protuberans (DFSP) • Atypical fibroxanthoma (AFX) • Microcystic adnexal carcinoma (MAC) • Desmoplastic trichoepithelioma (DTE) • Verrucous carcinoma • Keratoacanthoma (KA) • Erythroplasia of Queyrat • Extramammary Paget’s disease

• Medications and allergies – anticoagulants, anesthetics, and surgical scrubs may need to be adjusted • Propensity for infection at surgical site or elsewhere – indications for preoperative and postoperative antibiotics • Alcohol and tobacco history • Presence of implants such as defibrillators, pacemakers, or deep brain stimulators that affect choice of hemostatic device • Necessity of preoperative imaging based on tumor characteristics and symptoms • Preoperative consultations (plastics, oculoplastics, head and neck surgeons) • Psychological preparation of the patient, particularly when defect is expected to be large, disfiguring, or potentially to lead to long-term structural damage or nerve dysfunction

• Sebaceous carcinoma • Apocrine carcinoma • Bowen’s disease • Bowenoid papulosis • Leiomyosarcomaa • Malignant fibrohistiocytomaa • Merkel cell carcinomaa • Angiosarcomaa • Melanomaa aCase

reports and controversial

and patient, various medical and psychologic issues are taken into consideration during evaluation and preparation of the patient for surgery. Important questions to address are included in Box 16-� 4.

The procedure The area is cleansed with a surgical scrub, typically Betadine® or chlorhexidine. The perceived tumor margins are carefully marked along with important cosmetic lines and units using a surgical pen or gentian violet (Fig. 16-� 3). The area is infiltrated with local anesthetic, typically 1% lidocaine with epinephrine 1 : 100 000. Lidocaine is the most commonly used anesthetic but the surgeon may choose to use another anesthetic based on its duration of action, cost, or allergenic potential. Some individuals have an intolerance to epinephrine, and plain lidocaine can be used in these circumstances. To minimize the stinging sensation that occurs from injection of unbuffered acidic lidocaine, the lidocaine can be buffered with sodium bicarbonate in a ratio of one part bicarbonate to nine parts lidocaine. Slow injection of the anesthetic will also ­decrease the uncomfortable burning sensation

Figure 16-3  The estimated tumor margins are marked with ink and the area is surgically scrubbed and anesthetized

that can occur with infiltration. Furthermore, pinching the adjacent skin while inserting the needle through a pore can decrease the pain of needle insertion. Ideally, the anesthetic is allowed to penetrate the larger nerves in the area for 5–10 min, and this will also allow time for the vasoconstrictive action of epinephrine to set in. Typically, a debulking procedure is performed prior to excision of the first Mohs layer (Fig. 16-� 4). The tissue of most interest is the border of normal tissue surrounding the tumor. Accordingly, gross pathologic tissue is usually removed and discarded, although many exceptions to this occur. If the tumor is particularly large or exophytic, tissue scissors or a scalpel may be used to remove obvious tumor mass. More commonly, curettage is employed to remove gross tumor and delineate gross tumor margins. Skin cancer is usually very friable and easily parts with normal tissue when using a ­curette. A rough estimate of tumor width

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Figure 16-4  Tumor is often debulked with a curette to aid in determination of initial incisions

Figure 16-6  Hash marks are placed in the skin and tumor for orientation purposes

Figure 16-5  Tumor is excised with a 1–2-mm margin of normal appearing skin. The scalpel is kept at an angle to bevel the skin edge and facilitate processing in the lab

Figure 16-7  The tissue is excised, keeping the deep margin in the same plane parallel with the surface of the skin

and depth helps to guide the surgeon with regards to the initial Mohs specimen (layer). The initial layer is then excised with a scalpel (Fig. 16-� 5). Although some authors have argued that incisions should be made perpendicular to the skin, a traditional bevel of the scalpel is most commonly employed. The bevel of approximately­ 45° allows easier orientation of the skin edge in the plane with deeper tissues, as discussed below. A single smooth cut is made around the tumor including a 1–2-mm margin of clinically normal appearing skin. The skin is nicked with a scalpel or marked with ink around the perimeter for orientation purposes (Fig. 16-� 6). A scalpel or tissue scissors may be used to transect the base of the excision parallel to the surface of the skin under the tumor. Care is taken to keep the deep margin within the same plane (Fig. 16-� 7). This also optimizes tissue processing and subsequent margin evaluation. The specimen can be processed in one piece or it may be divided into two or more pieces­ for processing. The tumor location, shape, size, and orientation marks are transferred to paper on the Mohs “map” (Fig. 16-� 8). Inks are used to mark the specimen and are placed carefully at the edges of the tissue; they will be used to map the location of positive margins (Fig. 16-� 9). The location and

Figure 16-8  Information regarding tumor location and location of hash marks is transferred to the Mohs “map” while the piece of skin is marked with inks and prepared for processing

color of inks are transferred to a paper Mohs map. The tissue pieces are laid on gauze for transfer to the Mohs histopathology laboratory (Fig. 16-10). The wound is dressed temporarily with a pressure bandage while the tissue is processed, and it

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A

B

C

D

E

F

Figure 16-9  The tissue is marked for orientation with one or more inks

Figure 16-10  The pieces are laid on gauze for transfer to the lab. Here, by convention, the first piece is in the upper left-hand corner closest to the ink dot and the skin edge is away from the dot. The second piece is on the bottom left and the third piece is on the upper right. Information regarding the color and location of ink is transferred to the Mohs “map”

is determined whether further layers need to be taken or whether the tumor has been removed completely and repair can begin.

Tissue processing and interpretation

Figure 16-11  Standard elliptical excision of tumor followed by vertical sectioning “bread-loafing.” Here, all margins appear to be clear based on the sections evaluated at the top of the figure. However, the positive margin between sections B and C was not evaluated

The success rate of Mohs surgery relates in part to the fact that the surgeon doubles as the histopathologist and, as such, has a more complete understanding of the many variables surrounding the case. Critical information is not lost in the transfer between multiple doctors. The Mohs surgeon is intimately familiar with the expected tumor pathology, understands exactly how and where the tissue was removed, and can readily interpret various findings under the microscope having just seen the patient clinically. Instant clinicopathologic correlation is obtained. Prior to interpretation of the tissue by the Mohs surgeon, the histotechnician has many key steps and should be thoroughly trained to orient, embed, freeze, section, mount, and stain sections

properly. Many sources of error can be introduced at each step and the technician needs to be intimately familiar with those sources of error so that recognition and correction are an ongoing process for quality control of the lab. If these steps do not lead to complete and interpretable tissue margins, the overall cure rate will suffer. The key difference between standard histopathologic processing and Mohs processing of the tissue surrounds tissue orientation and plane of sectioning. In standard histopathologic processing, the excised specimen is “bread-loafed” with multiple thin vertical sections cut from the block and prepared for examination (Fig. 16-11).

The sections give the pathologist a relative “sampling” of the surgical margin. This method leads to a handful of sections which are of the order of several microns, although the actual specimen may be several centimeters in multiple dimensions. In fact, it is estimated that standard processing presents less than 1% of the true surgical margin for evaluation by the pathologist. Based on this fact, it is not surprising that the cure rates for excision listed in Box16-1 are lower than with Mohs surgery and are based on recommended standard margins rather than histologic control. In contrast, Mohs processing involves sectioning the tissue in a horizontal rather than vertical plane. The skin edge is bent into the same plane as the deeper subcutaneous tissue margin, and sections are taken in a horizontal plane parallel to

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16

the surface of the skin (Fig. 16-12). In this ­manner, sections contain both the skin edge margin and the deeper subcuticular margins all within the same section. The Mohs map is used to orient the specimen, and the location of persistent tumor is indicated on the map to guide further tissue removal. A true section, as would be obtained based on Figure 16-12, is seen in Figure 16-13.

Management of postoperative defects and postoperative course Repair of postoperative defects is usually performed by the Mohs surgeon, although consultation with other surgical specialties is often

Slice

Slice section Figure 16-12  Schematic portraying tissue removal and manipulation of the skin edge such that the entire skin edge is in the same plane as the deeper tissue margin. Horizontal sections are taken in a bottom-up approach so that the first few sections are a representation of the true surgical margin comprising both skin edge and deeper tissues

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Further reading

Figure 16-13  Hematoxylin and eosin stain of a frozen section depicting half of the excised surgical margin. The inks used (blue and red) are clearly visible at the deep margin of the tissue, and the epidermis, dermis, and subcutaneous fat are all seen and evaluated in the section. In this case, the section is clear of tumor

appropriate. Some wounds are allowed to heal by second intention. Repair options include primary closure, flaps, grafts or delayed closure. Utilization of various wound care principles and closure techniques is addressed in other chapters. Complications with Mohs surgery are rare. Expected postoperative events include at least some degree of scarring, bruising, swelling, and post­ operative tenderness. Infection occurs in 1–2% of cases, and excessive bleeding or hematoma formation increases the likelihood of infection.

Cook J, Zitelli JA. Mohs micrographic surgery: a cost analysis. J Am Acad Dermatol 1998;39:698–703. Martinez JC, Otley CC. The management of melanoma and nonmelanoma skin cancer: a review for the primary care physician. Mayo Clinic Proc 2001;76:1253–1265. Messingham MJ, Arpey CJ. Update on the use of antibiotics in cutaneous surgery. Dermatol Surg 2005;31:1068–1078. Rowe DE, Carroll RJ, Day CL. Long-term recurrence rates in previously untreated (primary) basal cell carcinoma: Implications for patient follow-up. J Dermatol Surg Oncol 1989;15(3):315–328. Rowe DE, Carroll RJ, Day CL. Prognostic factors for local recurrence, metastasis, and survival rates in squamous cell carcinoma of the skin, ear, and lip: implications for treatment modality selection. J Am Acad Dermatol 1992;26:976–990. Thissen MR, Neumann MH, Schouten LJ. A systematic review of treatment modalities for primary basal cell carcinomas. Arch Dermatol 1999;135:1177–1183. Tromovitch TA, Stegman SJ. Microscopically controlled excision of skin tumors: chemosurgery (Mohs): fresh tissue technique. Arch Dermatol 1974;110:231–232.

Erin J. Allen and Summer R. Youker

Introduction Even the most experienced surgeons will have complications. With that in mind, preventing complications is preferable to managing them. Careful planning, meticulous technique, and good patient communication help the surgeon to avoid complications. It is important to give patients ­ wri­t­ten postoperative instructions and emergency ph­one numbers. Postoperative phone calls to check on patients’ status is an easy way to detect complications early and increases patient satisfaction. Many surgical complications can be avoided with careful preoperative planning (see Chapter 5: Pre­operative evaluation). Fortunately, overall complication rates are low for cutaneous surgery, and overall rates as low as 1.6% have been reported for Mohs micrographic surgery. A surgical complication can set off a chain reaction, causing further adverse events. Most complications are interrelated (Fig. 17-1). It is important to detect problems in a timely manner as early intervention can improve overall outcome.

Hematoma, ecchymosis, and seroma Key Points • Preoperative evaluation of anticoagulants or

coagulopathies can help prevent excessive intraoperative and postoperative bleeding. • Practice meticulous intraoperative hemostasis to prevent hematomas. • Evacuation of large hematomas is necessary to prevent further adverse outcomes (infection, necrosis, dehiscence). • Seromas are caused by collections of serous fluid. Prevention of seromas is accomplished by layered closure of all potential space during surgery.

17

Contact dermatitis

Seroma

Bleeding

Infection

Necrosis

Hematoma

Dehiscence

Tension

Chapter

Surgical complications

Widened scar Figure 17-1  Surgical complications algorithm

Hematoma (Boxes 17-1 & 17-� 2, Figs 17-2 & 17-� 3) Preoperative evaluation of patients, their coagulation history, and medications is important to help prevent hematoma formation (see Chapter 5: Preoperative evaluation). Warfarin and clopido­ grel are not routinely discontinued for dermatologic surgery. When possible, over-the-counter herbal remedies, nonsteroidal anti-inflammatory drugs (NSAIDs), and alcohol should be withheld. Aspirin does not appear to increase the risk of significant bleeding unless the bleeding time is prolonged, and bleeding time is prolonged beyond the normal range in only about 25% of aspirintreated patients. For minor procedures, the risk from aspirin is minimal. For larger procedures, determination of the bleeding time can assess the risk. Bleeding can cause a number of problems for both the patient and the surgeon. Intraoperative bleeding obscures the surgical site. It is important to maintain a dry field for visualization and to prevent later hematoma formation. ­ Meticulous hemostasis with precise ­ electrocautery during

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Dermatologic Surgery B ox 1 7 - 1

Causes of excessive bleeding Defects in coagulation cascade Platelet abnormality Medications

• Aspirin, NSAIDs, warfarin, clopidogrel, ethyl alcohol, vitamin E, garlic, gingko biloba, ginseng Physical problems



• Hypertension



• Lack of vessel retraction (incomplete sever)



• Transient vasoconstriction —epinephrine effect —traumatic vessel response



• Failure of adequate surgical hemostasis

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Treatment of hematoma Prevention

• Ensure international normalized ratio (INR) is not supra­ therapeutic in warfarin patients



• Cessation of anticoagulants preoperatively when medically appropriate



• Meticulous intraoperative hemostasis



• Pressure bandage Long-term massage and warm compresses for smaller hematomas Evacuation of larger hematomas



• Syringe with large-bore needle • Single suture removal Placement of drains as appropriate Antibiotics

a

b

surgery is key to controlling bleeding. Pay ­careful attention to the entire wound and explore the undermined edges for bleeding vessels. If the patient is in the Trendelenburg position, bleeding can be exaggerated. Larger vessels may need to be tied off at both ends with a figure-of-eight stitch with an absorbable suture. Vessels that have been incompletely severed will often continue to ooze. Once completely transected, the vessel will often contract and discontinue bleeding. Wound edge bleeding of the epidermal or papillary dermis can also be problematic. Avoid direct cauterization of the wound edges as epidermal char impedes healing. The placement of epidermal sutures will often stop superficial wound edge bleeding. The mattress suture is a good choice when there is significant papillary dermal bleeding. Other tools exist for patients in whom adequate attempts at hemostasis fail to stop bleeding. Special dressings containing hemostatic materials can be used in open wounds that continue to bleed. Products that facilitate hemostasis include gelatin sponges or powder (Gelfoam®), microfibrillar collagen (Avitene®, Collastat®), topical thrombin to speed coagulation, and oxidized cellulose (Oxycel®, Surgicel®). For particularly large defects or in patients with excessive bleeding, a small Penrose drain may be used. The drain is placed in the wound bed in a direction that allows it to exit the dependent portion of the wound. The wound is then closed, with a small opening left for the external portion of the drain. The drain may be removed in 24–48 h or left in place for up to 1 week. Postoperatively, a bandage composed of gen­ erous absorbable gauze and firm tape aids in wound compression. Ice applied to the wound site after surgery will also decrease bleeding due to vasoconstriction. Patients should limit their postoperative activity. Surgeons should give their patients strict and explicit written instructions with activity restrictions including lifting limitations and elevation of the site. This surgeon ­instructs patients to avoid all exercise other than walking, and to undertake desk duties at work for

c

Figure 17-2  (a) A stitch is removed from the bulging wound to reveal a hematoma. (b) Insertion of an instrument breaks up the clot and aids evacuation. (c ) Firm pressure expels the clot from the wound bed. (Photos courtesy of John Skougee MD)

a

17

c

b

d

Chapter

Surgical complications

e

Figure 17-3  (a,b) The patient, on warfarin, underwent two stages of Mohs surgery to clear a basal cell carcinoma on the lower back. Despite instructions to rest, the patient did yardwork and presented on postoperative day 1 with a rapidly expanding hematoma. (c) The flaps were taken down. The bleeding vessels were identified and tied off. (d) Drains were placed with the openings to the dependent portion and the flaps resutured into place. (e) There is necrosis of the left flap tip as a result of a relatively long length : width ratio, hematoma, and tension

at least 7 days. There should be no lifting greater than 10–15 pounds. When a hematoma occurs, there is often continued oozing from the site and pronounced swelling. Patients often complain of worsening pain, ­ especially if the hematoma is ­ expanding. Hematomas should be evacuated whenever possible, as they delay wound healing, facilitate epidermal necrosis, and serve as a nidus of ­infection. If a patient presents with a hematoma, evacuation should be attempted if the hematoma is large enough to palpate. The wound often does not need to be anesthetized, as epidermal reinnervation of the wound edges is not yet complete. If anesthesia is needed, then avoid epinephrine as it causes temporary vasoconstriction and can mask the culprit vessel(s). The incision site should be opened by removing the sutures; often, some of the sutures can be left in place. A no. 11-blade or large-bore needle on a syringe is then inserted into the wound at the incision line. Direct pressure or suction with the syringe is applied in all directions to aid hematoma evacuation. Any ­actively bleeding vessels should be cauterized or tied off. Once the hematoma is evacuated, the wound is flushed with copious amounts of sterile saline. The wound can be packed with iodiform gauze if a large space is present. Loose Steri-Strips can also be applied to reapproximate the wound ­edges and facilitate further drainage. Most authors recommend empiric antibiotics in the setting

of hematoma as the nutrient-rich collection is a breeding ground for infection. A first-­generation cephalosporin such as cefalexin is an appropriate first-line treatment option.

Ecchymosis (Fig. 17-4) Although often alarming to patients, ecchymosis alone rarely causes problems other than the temporary cosmetic appearance. Make certain that the ecchymosis is not masking a hematoma that should be addressed. Ecchymosis is more prevalent around the eyes, in the setting of blood thinners or coagulopathies, and in ­elderly skin. Surgery close to the eye, even when not on the eyelids, can

Figure 17-4  Ecchymosis. Note the extension well beyond the surgical site

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Dermatologic Surgery cause significant eyelid ­ ecchymosis. All ­ patients should be warned of the risk of ­ ecchymosis, ­especially those at high risk. Preparing patients for possible bruising can ­alleviate anxiety. Immediate postoperative ice can ­decrease bruising.

Seroma A seroma is a collection of serous fluid that ­accumulates in potential spaces after surgery. A complete and layered closure during surgery will eliminate potential space for fluid collection. Seromas can be detected as a soft mass beneath or adjacent to the suture line. They are often clinically mistaken for a hematoma. Insertion of a large-bore needle on a syringe with suction applied will drain a seroma. The fluid should be sterile. However, if the fluid is cloudy or other signs of infection are present, it should be sent for culture and antibiotics initiated. Seromas should be drained when possible, because the collection impedes healing and places pressure on the ­healing epidermis.

Dehiscence and epidermolysis (Boxes 17-3 & 17-4, Fig. 17-5) Key Points • Dehiscence is the separation of the layers of the wound.

• Epidermolysis is the separation of only the edges of the epidermis.

• Both occur as a result of other complications:

hematoma, seroma, infection, necrosis, improper repair design, and/or premature suture removal.

Epidermolysis and deeper dehiscence result from increased wound tension that is often caused by

B ox 1 7 - 4

Treatment of dehiscence and epidermolysis Resuture if 24 h Steri-Strips for wound support Minimal debridement as necessary Antibiotics not necessary, but recommended for large or high-risk areas

poor closure execution or by another complication. At the time of suture removal, the wound is only approximately 10% of original strength, and approaches 80% the tensile strength of ­uncut skin only at 8–9 months. Once dehiscence has ­occurred, the wound is typically left open and ­allowed to heal by secondary intent. If the wound is large, packing with an iodiform gauze dressing may be necessary to fill the void. The packing should be placed loosely in the wound and replaced with smaller packing every 3–5 days. The patient can also be instructed to remove a portion of the gauze each day to make room for healing tissue. Conservative debridement of fibrinous and devitalized tissue to a bleeding base is important as it allows for proper granulation. Closure can be attempted if the wound is clear of all infected tissue, and is best attempted within the first 24 h. If wound closure is ­attempted, then a curette or scalpel is used to freshen the wound edges to a bleeding base and layered sutures are placed. Prophylactic antibiotics can be started in cases of dehiscence if infection is imminent or likely, but are usually not necessary for epidermolysis.

B ox 1 7 - 3

Avoiding dehiscence and epidermolysis Limit patient’s postoperative activity Maintain a sterile field Avoid crush injury of tissue Avoid excess tension on wound Appropriate design

• Adequate undermining



• Remove standing cones Use proper suture material and placement Limit patient smoking Maintain hemostasis Figure 17-5  Wound dehiscence

Necrosis (Box 17-5, Fig. 17-6) Key Points • Necrosis is caused by compression of blood

vessels from sources such as tension on the wound, crush injury, infection, hematoma, and smoking. • The best treatment is continued observance, moist dressings, and antibiotics if there are signs of infection. • Extensive debridement is not recommended.

Necrosis occurs when vascular perfusion is compromised. Reiterating the relationship between adverse surgical outcomes, necrosis is usually the result of another complication. The superficial dermal plexus provides the main supply to the skin. Any of the previously mentioned complications can threaten this vascular plexus. Poor closure design places tension on the wound that is often evident after closure as pale and poorly perfused tissue. Extensive undermining in an excessively superficial plane will interrupt the ­feeding arterioles. Using the correct instrument such as hooks instead of forceps to lift rather than

B ox 1 7 - 5

Causes of epidermal necrosis Interference of blood supply

• Inadequate closure design



• Wound tension



• Crush injury from poor tissue handling



• Extensive superficial undermining Infection Hematoma Smoking

a

Chapter

Surgical complications

17

crush tissue will prevent tissue crush injury. Sutures placed in a layered closure help ­eliminate tension. Suture knots should be secure but not so tight that they compromise blood supply to the wound edges. Planning a flap or graft may be necessary when a complex closure will not suffice. Flap and graft necrosis rates range from 1.9% to 10.4%. The tip of the flap is the most ­vulnerable region as it is the most distal from the blood supply. Undersizing flaps is a relatively ­common mistake that demands too much of the flap, causes tension, and compromises blood ­ supply. Back-cuts into the flap pedicle or ­ improper length : pedicle ratio (3 : 1 is usually ­ appropriate) will also cause flap-tip necrosis. Lastly, the surgeon should not cut into the pedicle when ­taking the standing cone, as it will reduce the flap’s blood supply. Grafts derive their blood and nutrient supply from the wound bed. Cartilage and exposed bone are not suitable for grafts owing to the relative lack of blood supply. Areas of exposed cartilage on the auricle greater than 1 cm2 can be fenestrated with a 2-mm punch to facilitate graft perfusion from the underlying dermis. Exposed bone should be allowed to granulate, and a delayed graft placed when the wound bed is ready to accept a graft. Alternatively, the outer table of bone may be burred to stimulate bleeding before a graft is placed. A hematoma in the wound bed will interfere with graft survival. A bolster dressing and/or basting sutures aid adequate contact between the graft and wound base. Smoking contributes to numerous adverse surgical outcomes by directly and indirectly decreasing blood flow. Smoking more than one pack per day increases the risk of flap or graft necrosis threefold. All patients should be instructed to decrease, or if possible stop, smoking for 1 week before and 2 weeks after surgery. Necrosis is typically partial thickness. When wound necrosis is encountered, extensive

b

Figure 17-6  (A) Necrosis of a full-thickness skin graft. (B) Allowed to heal by secondary intent. (Photos courtesy of Mary Maloney MD)

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Dermatologic Surgery ­ ebridement is not recommended. Devitalized d tissue is dusky and frequently has a densely adherent eschar. Extensive debridement can injure deeper viable tissue. The wound should be cleansed frequently and kept moist with an ointment-based product, such as petrolatum.

Infection and mimickers (Table

17-1, Box 17-6, Figs 17-7–17-10) Key Points

• Infection usually begins at the time of surgery. • Infection is evident after 4–8 days. • Staphylococcus aureus is the most likely

B ox 1 7 - 6

Associations with increased surgical site infection Location – ear, hair-bearing, distal extremities, mucous membrane involvement, axillary or inguinal sites Significant break in sterile technique Surgery of a contaminated wound Long duration of surgery – infection rate almost doubles with each hour of surgery Comorbidities – poorly controlled diabetes, immunosuppression, malnutrition

organism – treat with a first-generation cephalosporin or penicillinase-resistant penicillin. • Abscesses should be drained and packed. • Signs of infection include redness, drainage, pain, crepitus, cellulitis, lymphangitis, fever, signs of endocarditis, shock. • Bacterial infection mimickers include viral infection, candidiasis, allergic and irritant contact dermatitis, and suture reaction.

Most dermatologic procedures are considered “clean-contaminated” and, although infection rates in these types of wound are accepted to be 5–10%, most dermatologic studies report lower rates. Pain or erythema that worsens with time should alert the patient and physician to evaluate the wound for infection. Most infections are introduced during surgery, but poor postoperative wound care can also contaminate the wound. Strict surgical

Figure 17-7  Postoperative bacterial infection. (Photo courtesy of Mary Maloney MD)

Table 17-1  Wound classification

Wound type

Defined

Infection rate

Clean

Sterile technique, noninflamed skin