Management of Orbito-zygomaticomaxillary Fractures [1st ed.] 9783030426446, 9783030426453

Table of contents :
Front Matter ....Pages i-viii
Zygomaticomaxillary Complex Anatomy (Hisham Marwan, Yoh Sawatari, Michael Peleg)....Pages 1-7
Preoperative Assessment before Orbital-Zygomaticomaxillary Surgery (Hisham Marwan, Yoh Sawatari, Michael Peleg)....Pages 9-21
Preoperative Surgical Planning (Hisham Marwan, Yoh Sawatari, Michael Peleg)....Pages 23-37
Surgical Access to Orbital-Zygomaticomaxillary Fractures (Hisham Marwan, Yoh Sawatari, Michael Peleg)....Pages 39-57
Fixation Techniques for Stabilizing Orbital-Zygomaticomaxillary Fracture (Hisham Marwan, Yoh Sawatari, Michael Peleg)....Pages 59-61
Soft Tissue Management in Orbital-Zygomaticomaxillary Surgery (Hisham Marwan, Yoh Sawatari, Michael Peleg)....Pages 63-71
Intraoperative Evaluation during Orbital-Zygomaticomaxillary Surgery (Hisham Marwan, Yoh Sawatari, Michael Peleg)....Pages 73-79
Postoperative Assessment After Orbital-Zygomaticomaxillary Surgery (Hisham Marwan, Yoh Sawatari, Michael Peleg)....Pages 81-88
Complications Associated with Orbital-Zygomaticomaxillary Surgery (Hisham Marwan, Yoh Sawatari, Michael Peleg)....Pages 89-97
New Advances in the Planning and Management of Orbital Zygomaticomaxillary Fractures (Hisham Marwan, Yoh Sawatari, Michael Peleg)....Pages 99-105
Management of Post-Traumatic Orbital Zygomaticomaxillary Deformities and Secondary Reconstruction (Hisham Marwan, Yoh Sawatari, Michael Peleg)....Pages 107-112

Citation preview

Management of Orbitozygomaticomaxillary Fractures Hisham Marwan Yoh Sawatari Michael Peleg

123

Management of Orbito-­ zygomaticomaxillary Fractures

Hisham Marwan • Yoh Sawatari Michael Peleg

Management of Orbitozygomaticomaxillary Fractures

Hisham Marwan Department of Surgery/Division of Oral and Maxillofacial Surgery University of Texas Medical Branch Galveston, TX USA King Abdulaziz University

Yoh Sawatari Department of Surgery/Division of Oral and Maxillofacial Surgery University of Miami/Miller School of Medicine Miami, FL USA

Jeddah Saudi Arabia Michael Peleg Department of Surgery/Division of Oral and Maxillofacial Surgery University of Miami/Miller School of Medicine Miami, FL USA

ISBN 978-3-030-42644-6    ISBN 978-3-030-42645-3 (eBook) https://doi.org/10.1007/978-3-030-42645-3 © Springer Nature Switzerland AG 2020 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Switzerland AG The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland

Preface

The management of maxillofacial fractures can be challenging. Overlooking a ­fracture may not have immediate consequences but can result in disfigurement and permanent disability. Not only does this result in severe emotional distress for a patient, but it may also affect their ability to continue being a productive member of our society. In “Management of Orbito-zygomaticomaxillary Fractures,” the authors present precise, concise, logical details on the management of the orbito-­zygomaticomaxillary fracture. This textbook presents the traditional concepts of ORIF techniques, as well as references to more modern technological advances, including intraoperative assessment and patient-specific planning and surgery. In a unique blend of descriptive text and images, the authors direct the reader through a detailed assessment phase, surgical approach and technique phase, as well as critical postoperative assessment. The writing is derived from extensive experience between the authors who have been performing facial trauma surgery over 20 years in one of the world’s busiest Level I Trauma Centers. Clear clinical photographs, pre- and postoperative CT scan imaging, and easy-to-understand diagrams support each chapter. This book is a required learning tool for interns, residents, and fellows, as well as a reference and refresher for the established practitioner. Galveston, TX Miami, FL  Miami, FL 

Hisham Marwan Yoh Sawatari Michael Peleg

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Contents

1 Zygomaticomaxillary Complex Anatomy������������������������������������������������   1 2 Preoperative Assessment before Orbital-­Zygomaticomaxillary Surgery��������������������������������������������������������������������������������������������������������   9 2.1 Clinical Examination��������������������������������������������������������������������������   9 2.1.1 Assessment for Function��������������������������������������������������������   9 2.1.2 Assessment for Facial Deformity��������������������������������������������  11 2.2 Radiographic Examination������������������������������������������������������������������  15 2.2.1 Defining the OZM������������������������������������������������������������������  15 2.2.2 Displacement (Degree and Direction)������������������������������������  18 2.2.3 Comminution��������������������������������������������������������������������������  18 2.2.4 Orbit����������������������������������������������������������������������������������������  19 3 Preoperative Surgical Planning����������������������������������������������������������������  23 3.1 Does the Patient Require Surgical Intervention?��������������������������������  23 3.2 Which Fractures Must Be Addressed?������������������������������������������������  24 3.3 Does the Orbit Require Reconstruction?��������������������������������������������  28 3.4 Which Access Type Will Be Necessary?��������������������������������������������  28 3.5 Surgical Sequence ������������������������������������������������������������������������������  30 4 Surgical Access to Orbital-­Zygomaticomaxillary Fractures������������������  39 4.1 Intraoral Approach������������������������������������������������������������������������������  39 4.2 Periorbital Approaches������������������������������������������������������������������������  41 4.2.1 Approaches to the ZF Suture��������������������������������������������������  41 4.2.2 Approaches to the Floor/Inferior Orbital Rim������������������������  44 4.3 Preauricular Approach������������������������������������������������������������������������  51 4.4 Coronal Approach ������������������������������������������������������������������������������  54 4.5 Gillies Approach ��������������������������������������������������������������������������������  57 Suggested Readings ������������������������������������������������������������������������������������  57 5 Fixation Techniques for Stabilizing Orbital-Zygomaticomaxillary Fracture������������������������������������������������������������������������������������������������������  59 6 Soft Tissue Management in Orbital-­Zygomaticomaxillary Surgery��������������������������������������������������������������������������������������������������������  63 6.1 Type of Soft Tissue Injuries����������������������������������������������������������������  64 vii

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Contents

6.2 Timing of Repair��������������������������������������������������������������������������������  66 6.3 Management of Primary Periorbital Injuries��������������������������������������  66 6.4 Management of Primary Cheek Injuries ��������������������������������������������  66 6.5 Soft Tissue Management during the Surgical Approach��������������������  67 6.5.1 Coronal Approach ������������������������������������������������������������������  67 6.5.2 Lower Eyelid Approach����������������������������������������������������������  67 Suggested Reading��������������������������������������������������������������������������������������  71 7 Intraoperative Evaluation during Orbital-Zygomaticomaxillary Surgery��������������������������������������������������������������������������������������������������������  73 8 Postoperative Assessment After Orbital-­Zygomaticomaxillary Surgery��������������������������������������������������������������������������������������������������������  81 8.1 Assessment������������������������������������������������������������������������������������������  83 8.1.1 Linear Measurements��������������������������������������������������������������  83 8.1.2 Angle Measurements��������������������������������������������������������������  84 8.1.3 Surface Area����������������������������������������������������������������������������  85 8.1.4 Volume������������������������������������������������������������������������������������  86 8.1.5 Comparison of Preoperative and Postoperative 3D Reconstruction������������������������������������������������������������������������  87 9 Complications Associated with Orbital-­Zygomaticomaxillary Surgery��������������������������������������������������������������������������������������������������������  89 9.1 The Failure to Achieve the Desired Outcome ������������������������������������  89 9.2 Iatrogenic Complications: Access-Related Complication������������������  93 9.3 Fixation Plate Exposure/Sensitivity����������������������������������������������������  94 9.4 Neurosensory Disturbances����������������������������������������������������������������  94 9.5 Alopecia from Coronal Incision����������������������������������������������������������  95 9.6 Eyelid Malposition������������������������������������������������������������������������������  95 10 New Advances in the Planning and Management of Orbital Zygomaticomaxillary Fractures ��������������������������������������������������������������  99 10.1 In-House 3D Printing������������������������������������������������������������������������ 102 10.2 Intraoperative Computed Tomography �������������������������������������������� 103 Suggested Reading�������������������������������������������������������������������������������������� 105 11 Management of Post-Traumatic Orbital Zygomaticomaxillary Deformities and Secondary Reconstruction�������������������������������������������� 107 11.1 Surgical Planning������������������������������������������������������������������������������ 108 11.2 Osteotomy and Fixation Technique�������������������������������������������������� 111 Suggested Reading�������������������������������������������������������������������������������������� 112

1

Zygomaticomaxillary Complex Anatomy

The zygomaticomaxillary complex (ZMC) fracture is a type of facial fracture that involves the development of a bony complex separated from the facial skeleton based on fractures approximating the suture lines of four bones: the maxillary, frontal, sphenoid, and temporal. The sutures lines involved are the zygomaticomaxillary (ZM), the zygomaticosphenoid (ZS), the zygomaticofrontal (ZF), and the zygomaticotemporal (ZT). It is important to note that the propagation of the fracture lines may not necessarily approximate the suture lines but will traverse along the path of least resistance. This is because the zygoma represents a strong prominent bone with four processes. When force is applied to the zygoma, the forces are often transmitted along with the four processes which include the maxillary, frontal, orbital (sphenoidal), and temporal. Displaced ZMC fractures may produce gross asymmetry based on loss of anterior projection of the malar eminence, alteration of the lateral projection of the zygomatic arch, and the disruption of the three-dimensional position of the globe. Fractures of the zygomatic bone are common in facial trauma, and understanding the anatomy and relationships of the zygoma to the adjacent anatomical structures is the key for successful treatment. In this chapter, we will discuss and illustrate the anatomy of the zygomatic bone, the articulation with the adjacent structures, and the anatomy of the orbital and periorbital structures. The zygomatic bone is responsible for the anterior and lateral projection of the face and is a strong buttress of the lateral portion of the middle third of the facial skeleton. Due to its prominent position, it is an integral part of facial esthetics. From a frontal view, the ideal position of the cheek (zygomatic)prominence is 10  mm lateral and 20 mm inferior to the lateral canthus. From the lateral view, the most prominent portion should be 1 mm behind the globe (Fig. 1.1). The zygomatic bone is relatively strong and made of compact bone. It is a quadrilateral in shape and articulates with four other bones: maxilla, sphenoid, temporal, and frontal bones. The zygoma articulates with the maxilla in two junctions, superiorly forming the inferior orbital rim and inferiorly forming the zygomaticomaxillary buttress (Fig. 1.2). The temporal junction of the zygoma will form the zygomatic arch.

© Springer Nature Switzerland AG 2020 H. Marwan et al., Management of Orbito-zygomaticomaxillary Fractures, https://doi.org/10.1007/978-3-030-42645-3_1

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1  Zygomaticomaxillary Complex Anatomy

2 Fig. 1.1  The surface anatomy and the topographic position of the zygomatic prominence

10 mm

20 mm Zygomatic prominence

Supraorbital notch Frontal bone

Lesser wing of sphenoid Greater wing of sphenoid

Superior orbital fissure Zygomaticofrontal suture

Orbital floor

Inferior orbital fissure Inferior orbital rim

Zygomaticomaxillary suture

Zygomatic bone

Infraorbital foramen

Fig. 1.2  Anatomic relationship of the zygoma. Frontal view

1  Zygomaticomaxillary Complex Anatomy

3

Zygomatic arch

Zygomaticofrontal suture

Zygomaticofacial foramen

Infraorbital foramen Zygomatic bone Zygomaticomaxillary suture

Coronoid process

Fig. 1.3  Anatomic relationship of the zygoma. Lateral view

The arch is laterally positioned, and relatively weak bone makes it a common site of a fracture. Medial to the arch is the mandibular coronoid process and the temporalis muscle; therefore, the severely depressed arch can result in trismus by preventing the forward movement of the coronoid process or by injury to the temporalis muscle. Two foramina arise within the bone, the zygomaticofacial and zygomaticotemporal, both will transmit their corresponding vessels and nerves (Fig. 1.3). Muscles’ attachment to the zygoma can be grouped, according to the surface of origin/attachment into two: the malar surface and the temporal surface. The first is the muscles attached to the malar surface which includes the zygomaticus major, the zygomaticus minor, and the levator labii superioris. The second group include the masseter and temporalis muscles (Fig. 1.4). Because the zygoma forms part of the lateral orbital wall and the orbital floor, fracture of the zygoma usually involves a fracture of the orbital floor or lateral wall or both. Thorough knowledge of the periorbital anatomy is essential to repair the related injuries. The eyelid is conveniently divided into two lamellae. The anterior includes the skin and orbicularis oculi. The anterior includes the skin and orbicularis oculi and the posterior contains the tarsal plate and the conjunctiva. The skin of

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1  Zygomaticomaxillary Complex Anatomy Orbiuclaris Oculi muscle

Temporalis muscle

Zygomaticus minor Levator Labii superioris

Zygomaticus major

Levator Anguli Oris

Buccinator

Fig. 1.4  Muscular attachment of the ZMC and the orbit

the eyelid is the thinnest of all the skin over the whole body, and it is loosely attached to the underlying muscle. Therefore, careful handling of this delicate tissue will always lead to a superior result. The orbicularis oculi muscle is the main protractor of the eyelid. It is divided into palpebral and orbital parts. The palpebral part overlies the eyelid, and it is subdivided to pretarsal, overlying the tarsal plate and preseptal, anterior to the orbital septum. The orbital part lies at the periphery of the palpebral portion of the muscle (Fig. 1.5). Deep to the orbicularis oculi is the orbital septum which is confluent with the periorbita. Arcus Marginale is the thickened junction of the periorbita and the orbital septum at the lower eyelid. The orbital septum retains the preaponeurotic orbital fat. It is divided into two pads in the upper lid and 3 in the lower one (Fig. 1.6). The levator palpebrae superioris and the Muller’s muscle will control the tone of the upper eyelid and regulate the resting position of the upper eyelid when the eye is open. The levator palpebrae superioris muscle is the primary elevator of the

1  Zygomaticomaxillary Complex Anatomy

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Superior rectus muscle Levator muscle Superior orbital septum Superior preseptal orbicularis muscle

Superior tarsal plate

Superior pretarsal orbicularis

Inferior tarsal plate Inferior pretarsal orbicularis Inferior preseptal orbicularis muscle

Inferior orbital septum

Inferior rectus muscle

Fig. 1.5  Anatomy of the upper and lower eyelid with emphasis on the orbicularis oculi muscle anatomy

eyelid. It arises from the sphenoid bone at the orbital roof and passes above the superior rectus muscle attaches to the tarsal plate and the orbicularis oculi muscle to form the upper lid crease. Muller muscle, which is a smooth muscle, supplied by sympathetic innervation lies deep to the levator palpebrae superioris. It is inserted at the superior border of the tarsal plate. The lower lid anatomy is similar. However, the lower lid retractors maintain the position of the lower lid. The lower lid retractor is known as the capsulopalpebral fascia is an extension of the inferior rectus. Its primary function is to maintain the lower eyelid position (Figs. 1.5 and 1.6). The tarsal plate is a dense, fibrous tissue that maintains the convex form of each lid. The length of each tarsal plate is 45 mm in both lids. The width of the upper tarsal plate is 10 mm, and the lower tarsal plate is 5 mm. Meibomian glands (sebaceous) are embedded within the tarsal plate.

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1  Zygomaticomaxillary Complex Anatomy

Post septal/preaponeuortic fat Superior orbital septum Levator aponeurosis Superior muller muscle

Inferior muller muscle Post septal fat Inferior orbital septum

Fig. 1.6  Anatomy of the upper and lower eyelid with emphasis on the orbital septum and the location of the orbital fat

The orbit is not conical in shape. It is a quadrangular pyramid with its base on the facial surface, and the apex is the optic foramen. Dimensions of the adult orbit include a volume of 30 ml and a lid skin to orbital apex distance of 5 cm. It is easier to divide the orbital cavity into thirds, anterior, middle, and posterior. The orbital rim is formed of thick cortical bone. Its strength arises from its continuity around the orbit. A significant amount of force is required to fracture the orbital rim (Fig. 1.7). The orbital floor is a very thin S-shaped bone. The orbital floor thickness is often 0.5 mm and separates the orbit from the maxillary sinus. It is concave anteriorly and convex posteriorly. The infraorbital groove and canal will traverse the floor from lateral to medial. The canal carries the infraorbital nerve from the pterygopalatine fossa to the infraorbital nerve. The posteromedial area of the floor is important. The maxillary sinus will create an expansion behind the globe that will

1  Zygomaticomaxillary Complex Anatomy

Orbital rim

Ethmoid bone

7 Lacrimal bone Lacrimal fossa Supraorbital foramen

Optic foramen

Superior orbital fissure

Tubercule

Nasal bone

Greater wing of sphenoid

Maxilla

Inferior orbital fissure and groove Infraorbital foramen

Fig. 1.7  Osteology of the orbital cavity

help to maintain the globe in its anterior-posterior position. This area of expansion is known as the postbulbar bulge. Computed tomography CT volumetric study clearly showed the importance of this area in the development of enophthalmos. If this area is not explored, a poor outcome is warranted. The lateral orbital wall is relatively strong and protects the globe. It is composed of the greater wing of the sphenoid and zygomatic bone. The lateral wall of the orbit inclines 45 degrees to aid in peripheral vision. The zygomatic bone will provide the attachment for the lateral canthal ligament (Whitnall’s tubercle); therefore, vertical displacement of the zygoma will result in hypoglobus and antimongoloid slant to the eye. The superior orbital fissure lies between the lateral wall and the roof, and it is communicating with the middle cranial fossa. The distance of the superior orbital fissure from the frontozygomatic suture is 35 mm. The superior orbital fissure contents are the cranial nerves III, IV, and VI, branches of ophthalmic division (V1) of the trigeminal nerve, and the ophthalmic vein. On the other hand, the inferior orbital fissure lies between the lateral wall and the floor, and it is communicating with the pterygopalatine fossa. The distance of the inferior orbital fissure to the rim is 20 mm. The inferior ophthalmic vein passes through the inferior orbital fissure.

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Preoperative Assessment before Orbital-­Zygomaticomaxillary Surgery

2.1

Clinical Examination

The clinical examination is divided into two separate components, an assessment of function and an assessment of acquired deformity.

2.1.1 Assessment for Function There are three major functional limitations that could potentially result from the OZM fracture. The first is diplopia. For vision, the two eyes focus on the same object and move in synchronous motion. Although the eyes are in different positions, they are able to focus on the same object and create one image with stereoscopic vision. Diplopia is caused by the inability of the eyes to coordinate focus such that two separate images are perceived. Most commonly, this can be the result of the affected globe having restricted movement, such that the two eyes cannot coordinate movement to focus on a single object (Fig.  2.1). Another cause may involve an alteration of globe position such that the axis of the globe is altered, and even though the globe is moving in synchronous, the patient is unable to focus due to the strabismus. For both these conditions, the primary cause will be the entrapment of orbital contents, muscle, fat, or a combination of both. In addition, post-­ injury edema may also cause a restriction of globe motility. More rarely, damage to the oculomotor nerve has been documented. Restriction of gaze in any direction should be further investigated by a forced duction test to differentiate restriction due to possible nerve pathology, edema, or physical muscle incarceration, which needs to be relieved immediately to avoid permanent damage. To perform a forced duction test, a few drops of 1 or 2% Portions of this chapter originally published in Surgical Management of Maxillofacial Fractures (Quintessence, 2019)

© Springer Nature Switzerland AG 2020 H. Marwan et al., Management of Orbito-zygomaticomaxillary Fractures, https://doi.org/10.1007/978-3-030-42645-3_2

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2  Preoperative Assessment before Orbital-­Zygomaticomaxillary Surgery

Fig. 2.1  Restriction of extraocular muscles creates diplopia for patient

Fig. 2.2  OZM fracture propagates through infraorbital nerve canal and may compress the nerve

lidocaine are placed into the fornix. A toothed forceps is used to grasp the sclera approximately 5–7 mm away from the limbus at the site of the insertion of the inferior rectus muscle. The eye is rotated in all vectors. Any physical restriction is considered a positive forced duction test indicating mechanical restriction. The second functional deficit is the sensory alteration of the maxillary branch of the trigeminal nerve. This often occurs from nerve contusion or constriction from the OZM fracture (Fig. 2.2). Although there is cortex surrounding the foramina, the infraorbital foramen represents a weak point in the zygomaticomaxillary complex, and fractures tend to propagate through this foramen. In addition, oftentimes the nerve is also damaged due to the orbital floor fracture, similar to isolated orbital floor fractures. Patients will often develop V2 paresthesia when the force propagation from the development of the OZM directly traumatizes the nerve coursing from the inferior orbital fissure to the infraorbital foramen. The third functional deficit involves the development of trismus (Fig.  2.3). Although patients who sustain OZM fractures will have difficulty opening their

2.1 Clinical Examination

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Fig. 2.3  Development of trismus due to depression of zygomatic arch against the coronoid process of mandible

mouth due to pain and edema, there is a need to differentiate between mechanical obstruction and guarding and pain. If the OZM complex is displaced posteriorly or significantly medial, then there is a possibility that the patient’s coronoid process will be restricted in movement during opening motions. If the patient presents with trismus that cannot be manipulated or opened due to the feel of a mechanical restriction, then most likely the OZM complex is the likely cause.

2.1.2 Assessment for Facial Deformity There are three areas of the face that are affected by an OZM fracture.

2.1.2.1 Orbit and Ocular Structures The various orbital manifestations of the OZM can be divided into categories including periorbital structures, sclera, globe position, functional limitations, and clinical signs associated with ocular morbidity. Grossly, the patient will present with edema, ecchymosis, and, on occasion, lacerations of the periorbital tissues including the eyelids (Fig.  2.4). Additional traumatic orbital findings involve the sclera, which includes chemosis and subconjunctival heme. Globe positioning is often affected by a displaced zygomaticomaxillary complex and can manifest itself in enophthalmos, exophthalmos, and dystopia. In addition, change in position of the palpebral fissure, antimongoloid slant, or ectropion may occur from downward and lateral displacement of the OZM on the lateral canthal ligament. Patients who present with enophthalmos require a full ophthalmologic and maxillofacial evaluation. The physical examination must include the soft tissue and bony components individually. The position of the eyebrow, lids, and the medial and lateral canthal ligament must be recorded and compared to the uninjured eye. The

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2  Preoperative Assessment before Orbital-­Zygomaticomaxillary Surgery

Fig. 2.4 Clinical appearance of a patient who sustained a displaced OZM fracture. Note the significant periorbital and malar edema

presence of supratarsal sulcus deformity indicates enophthalmos due to loss of support posteriorly and inferiorly. Furthermore, the globe position in relation to the orbital rim must be recorded using the Hertel exophthalmometer. Diplopia must be evaluated and recorded using the Hess chart. It is always prudent to have a comprehensive ophthalmologic examination performed by an ophthalmologist. This consultation will provide two valuable baseline assessment values. First, the exam will assist in determining the current condition of the eye and if any contraindications to surgery exist in the acute setting. Second, the comprehensive exam will provide a post-trauma presurgical baseline for the globe, which allows for postsurgical assessment of the globe and vision, in the event that surgical intervention may have led to an iatrogenic complication. In general, a comprehensive eye examination consists of seven components (EOM, papillary exam, funduscopic exam, slit lamp, visual acuity, tonometry, periorbital structures) and is customarily performed by the ophthalmologist. However, some components may be performed by the maxillofacial surgeon. Gross visual exam involving extraocular motility, visual fields, and acuity can be performed by the maxillofacial surgeon during the initial clinical evaluation. Visual field assessment and acuity are performed with a Snellen card, and each eye is compared to the other. The assessment of extraocular movement (EOM) for a conscious patient is

2.1 Clinical Examination

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customarily completed by requesting that the patient follow a designated target, such as a finger, in all 9 visual directions. The palpation of the periorbital structures associated with an OZM will reveal tenderness in the inferior orbital rim and lateral rim areas. In addition, steps, crepitus, mobility, possibly subcutaneous air, and hematomas may be discovered during the examination. A painful tense proptotic globe in association with a fixed dilated pupil with visual changes is a true emergency indicative of a retrobulbar hemorrhage which requires an immediate lateral canthotomy and cantholysis.

2.1.2.2 Malar Area During the evaluation of the malar area of an OZM fracture, edema, lacerations, hematoma, and ecchymosis is often noted. One of the most obvious clinical presentations of a displaced OZM fracture includes the gross asymmetry of the face. This asymmetry may be a manifestation of a depressed malar prominence or a unilateral widening or depression of the lateral face (Figs. 2.5, 2.6, and 2.7). These deformities are often better appreciated from a “bird’s eye” view standing from behind the head of the patient looking downward, or a “worm’s view” looking upward from below. The malar prominence is usually located 1 cm lateral and 2 cm inferior to the lateral canthus. When flattening of the malar prominence occurs, the complex is usually displaced posteriorly or rotated in medially. When the widening of the face is noted, the cause usually involves the medial rotation of the anterior component of the OZM, with lateral rotation of the zygomatic process at the arch. Bony steps, depression, and tenderness are findings often associated with palpation of the malar area of the OZM fracture. Loss of malar projection may be difficult to discern secondary to facial edema. It is very important to simultaneously palpate both sides of the face from a “bird’s eye” perspective for a better perception of the

Fig. 2.5  Depressed malar projection from posteriorly displaced OZM fracture

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2  Preoperative Assessment before Orbital-­Zygomaticomaxillary Surgery

Fig. 2.6  CT image of the depressed malar projection

Fig. 2.7  CT image of the widened zygomatic arch and increased transverse dimension

posterior displacement of the fractured complex. Finally, crepitus may also be palpable in the malar and periorbital soft tissue areas due to air emphysema from the maxillary sinus.

2.1.2.3 Zygomatic Arch The arch area of an OZM fracture commonly reveals depression of the lateral aspect of the cheek. In addition, ecchymosis, edema, steps, crepitus, and lacerations are also frequently encountered during the examination. The manifestation of zygomatic arch displacement depends on the vector in which the force is applied. If there is a force applied directly to the arch or from a lateral to direction, most commonly the arch will be fractured inward. However, if the force is applied to the complex in a posterior direction, the arch tends to displace in a lateral dimension. Steps, tenderness, edema, depression, and a mobile fragment of the arch are often palpated in the area of the arch secondary to an OZM fracture (Fig. 2.8).

2.2 Radiographic Examination

15

Fig. 2.8  Soft tissue edema along the zygomatic arch

2.2

Radiographic Examination

2.2.1 Defining the OZM A non-contrast maxillofacial CT with axial and coronal cuts at 1.5 mm increments is the standard radiographic study utilized in providing the information required to diagnose and plan for the treatment of the OZM fracture. The two primary purposes of reviewing the maxillofacial CT is to determine to confirm that the fracture exists and then to determine the potential need for surgery and the complexity of the procedure. The OZM has a defined pattern, and for the diagnosis to be confirmed, all four processes must be fractured on CT examination. Although this chapter focuses on the OZM fracture, it is the surgeon’s responsibility to thoroughly review the CT scan for additional facial fractures including the mandible and document any additional incidental findings that may be discovered during assessment. The CT examination customarily begins with the axial orientation. The axial CT is always obtained for the evaluation of a trauma patient with suspected head and neck injuries. The axial orientation allows the brain, cervical spine, and face to be evaluated at the same time. The image is always reviewed in a systematic fashion usually beginning with the superior most aspect of the face and progressing in an inferior direction. During the CT examination, all aspects of the facial bones should be examined, however for the purposes of confirming an OZM fracture, the first component encountered will be the zygomaticosphenoid fracture (Fig. 2.9). As the exam progresses inferiorly, the next fracture that will be identified is the zygomaticotemporal fracture, followed by the zygomaticomaxillary component (Figs. 2.10 and 2.11). If there is a fracture located at each of these locations, there is a very high suspicion of an OZM fracture. On the coronal orientation of the maxillofacial CT, a systematic examination progressing from the anterior aspect to the posterior is completed. The first fracture encountered on the coronal perspective is the orbital rim or zygomaticomaxillary component, and almost simultaneously the zygomaticofrontal component will come

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2  Preoperative Assessment before Orbital-­Zygomaticomaxillary Surgery

Fig. 2.9  Axial CT image of the fractured and displaced zygomaticosphenoid junction of the OZM fracture

Fig. 2.10  Axial CT image of fractured and displaced zygomaticotemporal junction of the OZM fracture

Fig. 2.11  Axial CT image of the fractured and displaced zygomaticomaxillary junction of the OZM fracture

2.2 Radiographic Examination

17

Fig. 2.12  Coronal CT image of the fractured and displaced zygomati­ cofrontal junction of the OZM fracture

Fig. 2.13  Coronal CT image of the fractured orbital floor of the OZM fracture

into view (Fig. 2.12). In addition, the coronal CT will confirm the presence of an orbital floor fracture (Fig. 2.13). With the four components (ZF, ZS, ZT, ZM) confirmed to be fractured, the diagnosis of the OZM can be established. The sagittal perspective may be utilized to determine the anterior to the posterior extent of orbital floor involvement associated with the OZM fracture, and additional views of the ZF fracture will be evident on the sagittal perspective (Fig. 2.14). The sagittal perspective is not necessary to diagnose an OZM fracture. Additional information may be obtained from the radiographic examination which will assist in determining the difficulty of the anticipated procedure along with which access type is most suitable.

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2  Preoperative Assessment before Orbital-­Zygomaticomaxillary Surgery

Fig. 2.14  Sagittal CT image of orbital floor fracture revealing the anterior-posterior length of the defect

2.2.2 Displacement (Degree and Direction) The amount of displacement must be examined at each junction of the OZM fracture. Displacement at the ZF and orbital rim will determine how much vertical displacement must be overcome to replace the complex into the appropriate position. The displacement at the ZS, ZT, and ZM buttress will provide information on how much rotational and linear displacement the complex has sustained thus how much correction will be required. The greater the displacement, the more difficult the reduction and fixation will be due to the degree of movement required for correction and soft tissue resistance (Figs. 2.15 and 2.16).

2.2.3 Comminution An evaluation of the degree of comminution must also be examined at every OZM fracture junction. The greater the comminution, the greater the distance between the complex and adjacent stable bone. This has a direct effect on the accuracy of reduction and stability at each junction of the OZM fracture. In addition, the procedure will become more difficult due to the need for greater access incisions, longer fixation plates, and loss of continuity. Comminution has a greater influence on the type of access that is utilized for OZM management than displacement. A displaced fracture without comminution can be manipulated via small access to reapproximate segments. However a fracture with significant comminution requires greater

2.2 Radiographic Examination

19

Fig. 2.15  Axial CT revealing displacement of zygomaticosphenoid junction

Fig. 2.16  Axial CT revealing displacement of zygomaticomaxillary junction

visualization and far greater access to reach the stable bone, and the distance between the stable bone to the OZM complex is greater (Figs. 2.17 and 2.18).

2.2.4 Orbit All OZM fractures involve the orbital floor. However, depending on the severity, the floor may require reconstruction. The size of the defect, the presence of medial and lateral floor support, the posterior extent of the defect, the presence of a medial wall

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2  Preoperative Assessment before Orbital-­Zygomaticomaxillary Surgery

Fig. 2.17  3D CT reconstruction of the face displaying significant comminution of the OZM complex secondary to gunshot wound

Fig. 2.18  3D CT reconstruction of a face displaying significant comminution of the OZM complex secondary to an industrial accident with high-velocity projectile

2.2 Radiographic Examination

21

Fig. 2.19  Comminution at the orbital rim, requiring surgical intervention

defect, and the displacement of the rim are all factors that must be considered when planning the reconstruction of the orbital floor. In addition, unlike isolated orbital floors, care must be taken to anticipate the reduction of the zygomatic complex. On occasion, the floor is not comminuted but the medial and lateral components of the floor appear significantly displaced, and when the complex is reduced, the floor defect reduces. The greatest influence the orbital floor defect has on OZM management involves the need for a periorbital approach. If the floor or medial wall requires reconstruction, periorbital access is required. This access will allow both the management of the floor and the rim component (Fig. 2.19).

3

Preoperative Surgical Planning

Once the examination of the patient is complete, several decisions must be made in a systematic fashion. 1 . Does the patient require surgical intervention? 2. Which fractures must be addressed? 3. Does the orbit require reconstruction? 4. Which access type will be necessary? 5. Surgical sequence. The answers to this series of questions will determine the surgical plan.

3.1

Does the Patient Require Surgical Intervention?

This is the primary question that needs to be addressed, and this decision is determined by the information acquired from both the clinical and radiographic examinations. Again the results of the examination determine the need for surgical intervention. The decision-making would start with the patient’s appearance. If there is significant skeletal deformity including obvious globe position alteration (dystopia, enophthalmos), or OZM complex malposition leading to malar depression, inferior displacement, or transverse widening, intervention is necessary. If there are palpable displacement/steps, crepitus, or mobility at the OZM complex fracture junctions, then intervention is likely necessary. If the patient presents with restriction of globe movement, alteration of the sensation of the affected maxillary branch of the trigeminal nerve, or mechanical trismus, a thorough examination of the CT scan is necessary to confirm that the cause of these functional deficits is a result of the OZM Portions of this chapter originally published in Surgical Management of Maxillofacial Fractures (Quintessence, 2019)

© Springer Nature Switzerland AG 2020 H. Marwan et al., Management of Orbito-zygomaticomaxillary Fractures, https://doi.org/10.1007/978-3-030-42645-3_3

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3  Preoperative Surgical Planning

Fig. 3.1 3D reconstruction of CT revealing significantly displaced OZM fracture

fracture. If there are these functional deficits with CT confirmation, then surgical intervention is necessary. Finally, there is the category of injury that lacks any functional deficit, and due to the lack of obvious clinical facial deformities, further evaluation becomes necessary. This often occurs due to the significant post-injury edema that ensues. The periorbital and facial edema make it difficult to visualize any obvious skeletal deformities, and due to the pain and guarding of the patient, palpating for fractures is somewhat difficult. For these cases, The CT may be reviewed to confirm the presence of an OZM fracture and investigate the amount of displacement at each fracture junction, the amount of comminution at every junction, and the need for orbital wall repair. If there is a moderate amount of displacement, comminution, or if orbital wall reconstruction is warranted, an intervention will be necessary (Fig. 3.1).

3.2

Which Fractures Must Be Addressed?

There are multiple factors involved with the decision-making on which components of the OZM require open access. As described above, once the decision has been made to intervene, it is important to determine which components of the complex are compromising function and appearance. Of the four components of the OZM, at least three must be in a stable accurate position to confirm that the complex is in its correct three-dimensional anatomic location. If three areas of the complex are accurately reduced and fixated, the fourth process will inherently reduce. Any combination of three fracture margins can be reduced for appropriate positioning. If less than three processes are reduced and fixated, there can be rotational instability along the

3.2  Which Fractures Must Be Addressed?

25

Fig. 3.2  Intraoral access utilized to visualize the zygomaticomaxillary junction of the OZM fracture

axis created by the two fixation points of the complex. However, if there is the minimal displacement with adequate stability at specific fracture junctions of the complex, less than three areas may be accessed and manipulated to achieve appropriate surgical outcomes. When considering the different components of the OZM, the only area which always requires exposure and manipulation is the buttress aspect of the zygomaticomaxillary junction. The buttress area of the OZM allows good visualization of the entire zygomaticomaxillary junction including the rim and the buttress. Although fixation of the infraorbital rim is difficult via intraoral access, the amount of displacement, as well as confirmation of reduction, can be made. In addition, exposure of this area is required to manipulate and reduce the complex to the appropriate position. Finally, this access is intraoral; therefore scarring on the face is not a concern, and there is minimal morbidity associated with this access (Fig. 3.2). The second area of the OZM that requires consideration is the zygomaticofrontal junction. This area can present with varying degrees of displacement and rotation. In general, when accessing this area, scaring can be hidden within the brow, and morbidity associated with the access is low. The necessity of accessing this area is determined by vertical, anterior-posterior, and rotational displacement. Vertical displacement can be measured on the coronal CT, anterior-posterior displacement can be assessed on an axial CT, and rotational displacement can also be assessed using the zygomatico-sphenoid junction of the complex. Any displacement that is palpable during the clinical exam or is visible on the CT (>1 mm) will likely be consistent with an unstable complex and clinical manifestations in function and/or form. Therefore with displacement, the zygomaticofrontal should be accessed and reduced. In addition, with the zygomaticofrontal fracture component exposed, the zygomaticosphenoid junction can be visualized for aid in reduction accuracy (Fig. 3.3).

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3  Preoperative Surgical Planning

Fig. 3.3  Access to the zygomaticofrontal junction with visualization of the zygomatico-sphenoid junction

The third area which requires consideration is the zygomaticomaxillary junction at the infraorbital rim. Any OZM with an orbital wall component (orbital floor ­and/ or medial wall) fracture which leads to functional entrapment or cosmetic deformities including dystopia and enophthalmos will require open access. In addition, if there is palpable rim displacement or vertical or anterior-posterior displacement as noted on the coronal and axial CT, access and reduction/fixation will be required. In addition, if there is comminution at the rim or suspected infraorbital nerve compression, periorbital access should be strongly considered. The difference between ZF and intraoral ZM access to the OZM is that periorbital access to the rim and floor has a greater potential for complications and associated morbidity (Fig. 3.4). The final process that requires consideration is the zygomaticotemporal junction. This junction is only accessible via a coronal approach. Coronal approaches are the most extensive access and allow for visualization and management of all aspects of the zygomatic arch and the zygomaticofrontal areas. In addition, the zygomaticosphenoid junction can also be visualized. The need to access the zygomatic arch is dependent on two separate conditions with the same underlying justification. First, in the event that there is significant comminution of the maxillary (rim and buttress) and frontal junctions, the ability to utilize those areas for accurate positioning and stability is diminished. Therefore, in these situations, the zygomaticotemporal junction must be reduced and fixated to establish the OZM. When properly reduced and fixated, the zygomatic arch provides anterior-posterior positional accuracy of the

3.2  Which Fractures Must Be Addressed?

27

Fig. 3.4  Fractures of the infraorbital rim and orbital floor

Fig. 3.5 3D reconstruction demonstrating the presence of concomitant fractures associated with ZMC fracture. The pattern of facial fracture requires a coronal approach to fixate the zygomatic arch

complex. Second, when there are multiple concomitant facial fractures, exposure of the arch is necessary to assure accurate positioning. The presence of a frontal sinus fracture can affect the stability of the zygomaticofrontal junction. The presence of a concomitant NOE will affect the stability of the zygomaticomaxillary orbital rim junction. The presence of a LeFort 1 fracture will affect the stability of the zygomaticomaxillary buttress component. Therefore when any of these additional concomitant fractures are present, strong consideration should be made to reduce and fixate the zygomatic arch (Fig. 3.5).

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3  Preoperative Surgical Planning

Fig. 3.6  Orbital floor component of the OZM fracture

3.3

Does the Orbit Require Reconstruction?

All OZM fractures involve the orbital floor. However, depending on the severity, the floor may require reconstruction. The size of the defect, the presence of medial and lateral floor support, the posterior extent of the defect, the presence of a medial wall defect, and the displacement of the rim are all factors that must be considered when planning the reconstruction of the orbital floor. In addition, unlike isolated orbital floors, care must be taken to anticipate the reduction of the zygomatic complex. On occasion, the floor is not comminuted, but the medial and lateral components of the floor appear significantly displaced, and when the complex is reduced, the floor defect reduces. The greatest influence the orbital floor defect has on OZM management involves the need for a periorbital approach. If the floor or medial wall requires reconstruction, periorbital access is required. This access will allow both the management of the floor and the rim component (Fig. 3.6).

3.4

Which Access Type Will Be Necessary?

For the OZM, access is based on the severity of the fracture. In general, the severity would refer to comminution rather than the degree of displacement. An OZM may be significantly displaced; however, if the complex remains as one unit, the reduction is relatively straightforward. However, if there is comminution of the complex especially at the junction of the zygomaticotemporal, zygomaticofrontal, or zygomaticosphenoid, a coronal approach would be recommended. The more comminuted the fracture, the more accessible the fractures need to be to provide the appropriate reduction and fixation. Essentially, the primary objective of fracture access is to identify the junction of non-stable bone to stable bone.

3.4  Which Access Type Will Be Necessary?

a

29

b

Fig. 3.7 (a, b) Postoperative imaging revealing minor displacement of the ZT junction with all other junctions in good alignment

When referring to local approaches, access involves three separate incisions to approach the respective components of the OZM fracture. An intraoral approach is utilized to access the zygomaticomaxillary junction including visualization of the orbital rim. A periorbital approach is used to access the orbital rim and floor, and an incision in the lateral orbit area is utilized to access the zygomaticofrontal junction and visualize the zygomaticosphenoid junction. Although the intraoral incision is a LeFort incision, there is variability with regard to the periorbital and lateral orbital access. The periorbital access may involve the use of a transconjunctival, subciliary, subtarsal, or infraorbital incisions. The lateral orbit incision may involve the use of a brow incision or a blepharoplasty incision. The limitation of local approaches is that it does not provide access to the zygomaticotemporal junction. Therefore, there is some ambiguity of the final position of the temporal aspect of the complex. Regardless of how well a surgeon visualizes the other three components of the fracture or how well symmetry is assessed via palpation, due to the three-dimensional variability of the complex, the final reduction of the zygomaticotemporal junction remains somewhat variable. However, in general, if the other three junctions appear well reduced and the reduction is confirmed by the zygomaticosphenoid, any minor variability of the zygomaticotemporal does not manifest in a significant deformity (Fig. 3.7). As opposed to the local approach to the OZM, a coronal approach provides far greater visualization of the various components of the complex. The coronal incision allows the surgeon to visualize the zygomaticotemporal, the zygomaticofrontal, and the zygomaticosphenoid junction. Although there is a risk to the frontal branch of the facial nerve, the coronal access confers the surgeon the ability to fixate any comminuted OZM component to the stable bone, thus providing the surgeon and the patient with the best possible outcome for complex fractures. As a confirmation, the outcome is determined by the restoration of orbital volume, restoration of

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3  Preoperative Surgical Planning

Fig. 3.8  The use of coronal access to maximize visualization to assure appropriate reduction of the OZM complex

periorbital continuity, restoration of anterior projection, and the appropriate lateral positioning of the complex. As discussed earlier, In addition to the coronal, the periorbital and intraoral access to the zygomaticomaxillary junction still remains a necessity to appropriately manage the OZM fracture (Fig. 3.8).

3.5

Surgical Sequence

The sequencing when reducing and fixating an OZM fracture is important. The general rule is to begin with the zygomaticofrontal suture. The rationale for the initial step involves the fixation of one dimension of the fracture which is the superior-­inferior displacement (Fig. 3.9). A smaller plate, usually a 1.5 mm fixation plate, is utilized with three screws in the stable bone and three in the complex. Once reduced, dissection can proceed along the lateral orbital wall, assessing the adequacy of the reduction via the zygomaticosphenoid suture. To assist with the reduction, a curette is often utilized to remove the granulation tissue in the junction of the fracture. Additional steps in the appropriate reduction of the fracture involve the use of a Kocher, bone reduction forceps, or 26 gauge stainless steel wire to assist in reducing the fracture prior to fixation. When fixating, screws are placed in the complex first; this provides a handle that allows the superior distraction of the complex. Care must be taken not to deform the plate during this maneuver, and consistent with all fracture plating, the plate should sit passively on the fracture, no matter how small the plate, to prevent inadvertent distraction. This fixation provides stabilization of the fracture while allowing the rotation of the complex in vertical access. In addition, with a small 1.5 mm plate, the maxillary buttress has the freedom to rotate medially to achieve an ideal reduction (Fig. 3.10). Following the fixation of the zygomaticofrontal junction, the next approach would be the orbital rim component. The rim is important since the tissues

3.5  Surgical Sequence

31

Fig. 3.9  Fixation of the ZF junction will accurately reposition the complex in a superior to inferior dimension

Fig. 3.10  Fixation at the ZF junction still allows the complex to be rotated along a vertical axis for appropriate positioning and reduction

overlying the rim are very thin. Any step or continuity defect of the rim leads to an easily palpable deformity which becomes unacceptable to the patient. In addition, oftentimes, displacement in the orbital rim component is indicative of orbital floor fractures and changes in orbital volume. In order to reduce the rim, the complex may be rotated medially utilizing any of the methods mentioned. While the orbital rim is reduced, an inspection of the maxillary buttress should be performed to assure that the complex is reduced in the appropriate anterior-posterior vector. Once an appropriate position is confirmed, additional plating can be performed at the orbital

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3  Preoperative Surgical Planning

Fig. 3.11 Accurate reduction and fixation at the ZF, ZM orbital rim, and ZM maxillary buttress junctions allow for the reduction of the ZT junction and appropriate OZM complex positioning

rim. Usually, a lower profile plate is utilized to minimize the palpability of the plate post-insertion. Usually, a 1.0 or 1.2  mm plate can be used. The same principles apply in which three screws are utilized on the complex and on the stable bone. However, since the rim sustains no stress or tension, two screws may be used on each segment to avoid any inadvertent damage to the eyelid or adjacent soft tissues and lacrimal duct. Similar to the zygomaticofrontal approach, screws are placed on the complex first, and the plate becomes a handle to assist the distraction of the complex towards the stable bone. Passivity is again of utmost importance. Once the rim is fixated, attention is then taken to the maxillary buttress. At this point, there is very little mobility of the complex; however, if required, minor movements can still be made to achieve an ideal reduction. A 1.5 plate may be utilized to bridge the complex to the stable bone of the maxilla. When placing the plate, care must be taken to avoid damage to the dental roots, especially the canine. The position of the canine is usually the most identifiable since the tooth has the longest root of the anterior teeth. In addition, surrounding the root, there is often a maxillary concavity adjacent to the root of the canine. In general, the plate may extend from the buttress to the piriform rim. The buttress and the piriform rim have the thickest cortex and represent the best location for screw fixation, and following the principles of rigid fixation, three screws should be used on both the complex and the stable bone. If there is comminution in the area of the maxilla, a mesh can be used to cover the defect; however, if the framework of the OZM is stable and in the appropriate position, the soft tissue can be draped over the defect, and a fibrous capsule will form over the defect (Figs. 3.11, 3.12, and 3.13). When the coronal access is utilized, the major difference involves access to the zygomaticotemporal junction. In the surgical sequence delineated above, the zygomaticotemporal junction will be accessed prior to the orbital rim. Even if the zygomatic arch does not receive direct trauma, due to its fragility, the arch oftentimes is fractured in multiple segments. Care must be taken to avoid delivering the bones of

3.5  Surgical Sequence

33

Fig. 3.12  Frontal View: Sequence of reduction/ fixation for local approaches: (1) ZF; (2) ZS confirmation; (3) ZM orbital rim; (4) ZM maxillary buttress

the zygomatic arch from the surgical site due to the minimal diameter and limited soft tissue attachments. The key to the zygomatic arch is to reduce the fractured segments to restore anterior-posterior projection of the ZM complex. Care must be taken to assure that the root of the arch is in the appropriate position. Oftentimes the root of the arch is laterally displaced; however, when accessed via a coronal incision, the root appears reduced and stable. If the reduction of the fracture begins with a displaced root, the anterior-posterior displacement of the arch will be foreshortened, and the absolute position of the ZM complex will lead to a deficiency of facial projection. In addition, the arch is a linear bone. Often when reducing the segments, the natural tendency for the surgeon is to reduce the fracture in a slight curve. This curve is applied to the arch via the fixation plates and ultimately leads to a deficiency in anterior projection and a widening of the lateral face. In general, a higher profile plate is utilized due to the tendency of the masseter muscle to distract the complex in a posterior vector. A more rigid plate will assist in maintaining the

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3  Preoperative Surgical Planning

Fig. 3.13  Lateral View: Sequence of reduction/ fixation for local approaches: (1) ZF; (2) ZS confirmation; (3) ZM orbital rim; (4) ZM maxillary buttress

anterior projection of the complex. Even after the ZF and ZT junctions are fixated, the complex still has the mobility in a medial-lateral rotation to reduce the orbital rim and buttress to the appropriate position (Figs. 3.14, 3.15, 3.16, and 3.17). Finally, once all junctions of the OZM complex are fixated, the orbital floor may be approached. Oftentimes once the complex has been restored in the most ideal position, the floor may not require reconstruction. However, if there is significant comminution or a defect exists in the orbital floor, reconstruction is required. At this stage, the reconstruction of the orbital floor is the same as an isolated orbital floor defect, and the same techniques apply. The only exception to consider is the position of the orbital rim plate which often requires additional planning when locating a fixation point for the orbital floor plate.

3.5  Surgical Sequence Fig. 3.14 Reduction/ fixation at the ZF junction reestablishes vertical positioning, reduction/ fixation at ZT junction reestablishes anterior OZM complex

Fig. 3.15  Fixation at the ZF junction still allows the complex to be rotated along a vertical axis for appropriate positioning and reduction of the complex

35

36 Fig. 3.16  Frontal View: Sequence of reduction/fixation for Coronal approaches: (1) ZF; (2) ZS confirmation; (3) ZT; (4) ZM orbital rim; (5) ZM maxillary buttress

3  Preoperative Surgical Planning

3.5  Surgical Sequence Fig. 3.17  Lateral View: Sequence of reduction/ fixation for Coronal approaches: (1) ZF; (2) ZS confirmation; (3) ZT; (4) ZM orbital rim; (5) maxillary buttress

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4

Surgical Access to Orbital-­ Zygomaticomaxillary Fractures

4.1

Intraoral Approach

The intraoral approach, also known as a Le Fort incision or vestibular incision, is the most common and versatile incision used to approach the midface structures. It provides adequate exposure to the zygomaticomaxillary buttress, the piriform buttress, the inferior orbital rim, and the anterior aspect of the zygomatic arch. The incision should be placed about 5–10 mm superior to the mucogingival junction. A simple way to determine the location of the incision is to bisect the distance between the mucogingival line and the depth of the vestibule. This distance will provide sufficient movable tissues for closure. The surgeon should always be aware of the location of Stensen’s duct and protect it throughout the procedure (Fig. 4.1). Local anesthetic with epinephrine can be injected for hemostasis. The incision is made with a scalpel or electrocautery. We prefer the setting for the electrocautery to be at 25–25 and on pure to minimize the thermal injury postoperatively. The incision should extend from the midline anteriorly to the level of the first molar posteriorly. Extending the incision more posterior will result in possible bleeding from the posterior superior alveolar artery and increases the likelihood of exposing the buccal fat pad. All of the incisions should be made perpendicular to the mucosa, to submucosa, and down to the bone. The first incision will cut through the mucosa and submucosal layers; a gauze then used to spread the mucosal margin and identify the underlying muscle. Subsequently, the incision should be carried down to the periosteum. Once the incision extends to the surface of the bone, the mucoperiosteal tissues should be reflected with a No. 9 Molt Periosteal elevator. Maintaining a subperiosteal plane is the key to this approach; it will help to identify all the critical structures and prevent complications. The reflection should extend anteriorly to the level of the anterior nasal spine, superiorly to the level of the inferior orbital rim and laterally to expose the zygomaticomaxillary buttress and the anterior aspect of the zygomatic arch. During the reflection, care should be exercised to protect the nasal mucosa anteriorly and the infraorbital nerve superiorly. The infraorbital foramen, which © Springer Nature Switzerland AG 2020 H. Marwan et al., Management of Orbito-zygomaticomaxillary Fractures, https://doi.org/10.1007/978-3-030-42645-3_4

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40

a

4  Surgical Access to Orbital-­Zygomaticomaxillary Fractures

b

Fig. 4.1 (a) Location of the Stensen’s duct. (b) Marking of intraoral vestibular incision with the protection of the Stensen’s duct Fig. 4.2  The amount of exposure that can be achieved utilizing the intraoral approach

transmits the neurovascular bundle, is located about 5–7 mm below the infraorbital rim. Finally, a limited dissection inferior to the mucogingival junction is performed to expose the alveolar bone and the dental roots’ prominence. This maneuver will expose additional bone for fixation and will allow mobilizing the soft tissue for closure (Fig. 4.2).

4.2 Periorbital Approaches

41

In most of the orbital zygomaticomaxillary fractures, there is significant comminution of the anterior maxillary wall. Maintaining the position of the comminuted segments is essential to allow for proper reduction of the complex and decrease the bleeding from the maxillary sinus. Therefore, every effort should be made to prevent lifting the comminuted segment with the periosteal flap. After the open reduction and internal fixation procedure are completed, the incision is closed, either single or double layer depending on the surgeon’s preference, using a resorbable suture in a running fashion, and no drain is required.

4.2

Periorbital Approaches

All of the periorbital approaches require globe protection before any incision or manipulation. Two options for globe protection are available: the tarsorrhaphy, i.e., using a suture, temporarily closes the upper and lower eyelid together, or corneal shield. Moreover, since all of the OZM fractures will involve the orbit, a forced duction test must be performed before and after the repair in order to rule out any mechanical entrapment of the orbit (Fig. 4.3).

4.2.1 Approaches to the ZF Suture Any approach for the zygomaticofrontal suture should provide full visualization of the fracture such that appropriate reduction and fixation can be performed. This bony suture line is usually located approximately 1 cm superior to the lateral canthus. Also, it is necessary to visualize the zygomaticosphenoid suture (ZS) from the access to assess for appropriate reduction. Fig. 4.3 Illustration showing all the periorbital approaches

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4  Surgical Access to Orbital-­Zygomaticomaxillary Fractures

4.2.1.1 Lateral Eyebrow This approach is a simple, straightforward approach to the zygomaticofrontal (ZF) suture for reduction and plating. There are no vital neurovascular structures around this anatomical region. However, the incision will usually leave a conspicuous scar if extended beyond the eyebrows. Therefore, we recommend using this incision with a preexisting laceration or a scar in the area of the planned incision. The incision is placed within or at the superior edge of the eyebrow. The length of the incision should be 2  cm. Local anesthetic with vasoconstrictor is usually administered before the incision to help in hemostasis. If the incision is placed within the eyebrow, it should be parallel to the hair follicle to avoid losing the hair of the eyebrow. The incision should proceed through the skin and subcutaneous tissues. Bipolar electrocautery is then used to stop all the subdermal bleeding. Senn retractors are used to retract the skin edges and help in the identification of the orbicularis oculi muscle. With palpation, the lateral rim is easily identified, and a sharp incision through the muscle down to the periosteum is made. Once the periosteum is incised, a periosteal elevator is used to reflect the tissues on both medial(intraorbital) and lateral direction to expose the fracture. When dissecting on the medial aspect (intraorbital), care should be taken to avoid injuring the lacrimal gland; the gland is located at the lacrimal fossa, and careful subperiosteal dissection will avoid exposure and potential injury of the gland. If a longer incision is desired, the extension should be made superiorly (within the eyebrow) and never inferiorly to avoid the postoperative scar. Closure of the incision should be done in layers, starting from the periosteum closure on top of the hardware. Subsequently, closure of the orbicularis muscles is done with resorbable sutures, and finally, the skin is closed using subcuticular monocryl or fast-absorbing gut. 4.2.1.2 Upper Blepharoplasty Similar to the lateral eyebrow approach, the upper blepharoplasty will provide excellent access to the zygomaticofrontal suture (ZF) with the advantage of a well-­ hidden scar. The anatomical structure of the upper and lower eyelid is shown in Fig. 4.4 and discussed in detail in the first chapter of this textbook. The incision is marked at the level of the supratarsal crease (about 10 mm above the central upper lid margin and 6  mm laterally). This crease can be difficult to visualize with periorbital edema; therefore, using the previously mentioned measurements from the upper lid margin and comparing it to the contralateral side is very helpful in these situations. The incision may be extended into a skin crease in the lateral lid if present; otherwise all efforts should be made to remain in the supratarsal crease. Local anesthetic with vasoconstrictor is usually administered before the incision to help with hemostasis. The incision is made through the skin only. Immediately below, the skin is the orbicularis oculi muscle. Once identified, it should be sharply dissected down to the level of the post orbicularis plane (Fig. 4.5).

4.2 Periorbital Approaches

43

Superior rectus muscle Levator muscle Superior orbital septum Superior preseptal orbicularis muscle

Superior tarsal plate

Superior pretarsal orbicularis

Inferior tarsal plate Inferior pretarsal orbicularis Inferior preseptal orbicularis muscle Inferior orbital septum Inferior rectus muscle

Fig. 4.4  Anatomy of the upper eyelid

Subsequently, scissor dissection is performed at the level of this areolar plane directly toward the fracture. Care must be taken to avoid dissecting into the lacrimal gland. The gland is located at the lacrimal fossa and looks more tan in color and more lobulated than fat. The skin muscle flap is retracted laterally, and the periosteum sharply incised, exposing the fracture (Fig.  4.6). For closure, the wound is closed in layers, starting from the periosteum closure on top of the fixation plate. Subsequently, closure of the orbicularis muscles is completed with resorbable sutures. In order to maintain the position of the supratarsal crease, 3 or 4 interrupted 7-0 Vicryl sutures are passed from the orbicularis oculi through the levator aponeurosis to fix the lid crease (Fig. 4.7). Finally, the skin is closed using a subcuticular monocryl or fast-absorbing gut. Figure 4.8a, b shows a well-healed incision 1 month after the procedure.

44

4  Surgical Access to Orbital-­Zygomaticomaxillary Fractures

1.

2.

Orbital septum

Fig. 4.5  Incision through the orbicularis oculi muscle down to the level of the post orbicularis plane

Fracture at the ZF suture

Fig. 4.6  Sharp dissection for exposure of the fracture at the zygomaticofrontal suture

4.2.2 Approaches to the Floor/Inferior Orbital Rim The surgical approaches to the floor and the inferior orbital wall can be divided into transcutaneous approaches and the transconjunctival approach. The transcutaneous approaches include the subciliary, midtarsal (subtarsal), and infraorbital approaches. The surgeon’s preference, experiences, and the presence of an existing laceration dictate what type of approach should be used. Placement of transcutaneous incision away from the lid margin will decrease the incidence of ectropion but will leave an

4.2 Periorbital Approaches

45

1.

2. Orbital septum

Pretarsal Orbicularis Oculi Muscle

Fig. 4.7  Surgical technique for recreating the supratarsal crease

a

b

Fig. 4.8 (a) A well-healed upper blepharoplasty incision 1  month after the procedure. (b) 3D reconstruction showing the titanium plates and the postoperative repair of the fractured ZMC

46

4  Surgical Access to Orbital-­Zygomaticomaxillary Fractures

unsightly scar. Therefore, the subciliary incision will provide the best cosmetic outcomes but will increase the likelihood of postoperative ectropion. In our experience, transconjunctival incision is the best approach to the inferior orbital rim, orbital floor and can be extended into the transcaruncular approach if the medial wall needs to be repaired. The only two indications of performing a transcutaneous approach instead of transconjunctival are the existence of lower eyelid laceration and the presence of severe periorbital edema, which makes the transconjunctival approach difficult.

4.2.2.1 Subciliary The planned incision is placed 2 mm below the lower lid margin in one of the skin creases. The incision should start 1 mm temporal to the inferior puncta and extends laterally toward the lateral canthal angle. Temporary tarsorrhaphy sutures are placed on the lower tarsal plate with careful protection of the inferior lacrimal punctum. Local anesthetic with vasoconstrictor is usually administered before the incision to help in hemostasis. Subsequently, the incision is made through the skin, only identifying the underlying pretarsal orbicularis oculi muscle. Careful hemostasis is achieved using bipolar electrocautery. The subcutaneous dissection is performed using a sharp scissor toward the inferior orbital rim for approximately 5 mm. This dissection will separate the skin from the pretarsal orbicularis muscle. The same scissor is then used to dissect into the preseptal orbicularis oculi muscle and create a pocket from the lateral aspect of the incision toward the medial. The incision of the muscle is done in a step fashion to prevent direct scarring and potential ectropion. Now the septum is identified, a fine tip skin hook is used to retract the inferior skin muscle flap laterally, and the dissection proceeds inferiorly once more until the rim is identified. This maneuver will prevent any fat herniation into the field. Finally, the periosteum is incised about 3–4 mm below the inferior orbital rim for access to the rim and the floor (Fig. 4.9). The No. 9 periosteal elevator is used to strip the periosteum from the underlying bony structures. Once the rim is completely exposed, the periosteal elevator is positioned vertically to dissect the periorbita from the orbital floor. At this level, the inferior oblique muscle might be encountered, and careful dissection of this muscle is performed to be included with its periosteal attachment. Every effort should be made not to cut or incise through the muscle to prevent postoperative complications with diplopia. Once the procedure is completed, closure of the wound is usually done in three layers. Starting from the periosteum closure on top of the hardware. Subsequently, closure of the orbicularis muscles is done with resorbable sutures (7-0 Vicryl), and then, the skin is closed using subcuticular monocryl or fast-absorbing gut (6-0). 4.2.2.2 Midtarsal Approach (Subtarsal) The skin incision for the midtarsal approach is made at the mid-level of the lower eyelid, in one of the skin creases about 3–4  mm below the lower lid margin (Fig. 4.10). Although the scar might be more evident than the subciliary, there is a

4.2 Periorbital Approaches

47

Tarsal plate

Pretarsal orbicularis oculi

Preseptal orbicularis oculi

Orbital septum

Inferior orbital rim

Fig. 4.9  Demonstration of the surgical dissection of the subciliary approach

significant reduction of postoperative ectropion with this approach [1]. The rest of the surgical technique is similar to the subciliary approach.

4.2.2.3 Infraorbital Approach This approach is the most straightforward transcutaneous approach to the inferior orbital rim and floor. However, it results in the most significant scarring, particularly in young individuals. The incision is located at the palpebral malar groove (infraorbital crease), and it usually extends up to 4 cm in a curvilinear fashion. It is recommended to perform the incision in a step fashion similar to the subciliary approach to prevent postoperative scarring of the skin to the periosteum (Fig. 4.11). One other concern in this approach is the infraorbital nerve since the incision is placed directly on top of the nerve; however, careful palpation of the orbital rim as a reference during the dissection will minimize the injury to the nerve. 4.2.2.4 Transconjunctival Approach The transconjunctival approach is our workhorse approach for accessing the inferior orbital rim, orbital floor, and medial wall fractures. This approach is straightforward

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4  Surgical Access to Orbital-­Zygomaticomaxillary Fractures

Tarsal plate

Pretarsal orbicularis oculi

Preseptal orbicularis oculi

Orbital septum

Arcus marginalis Inferior orbital rim

Fig. 4.10  Demonstration of the surgical dissection of the midtarsal (subtarsal) approach

and easy to perform with no risk of scarring. The only risk of a transconjunctival approach is the postoperative entropion with a reported incidence of 4%; however, precision in performing the procedure will eliminate that risk. Evaluation of the periorbital soft tissue for edema is necessary before selecting this approach. The presence of severe edema will narrow the palpebral fissure and make the retraction extremely difficult, thus, increasing the likelihood of lower eyelid avulsion and postoperative entropion. Finally, we have not found that the lateral canthotomy and inferior cantholysis are indicated in most if not all of the cases. Instead, once the inferior orbital rim is exposed, we use the No. 9 periosteal elevator to release the orbitozygomatic ligament laterally, and this will aid drastically in the retraction of the lower eyelid. There are two well-described variants of the transconjunctival approach, the preseptal and retroseptal. These two variations are differing in the location of the incision with the orbital septum. The main objective of the transconjunctival approach in the setting of trauma is to approach the rim and the orbital floor to perform reduction and fixation. Therefore, the most straightforward method with the least potential complication is the retroseptal approach. The retroseptal approach will avoid

4.2 Periorbital Approaches

49

Tarsal plate

Pretarsal orbicularis oculi

Preseptal orbicularis oculi

Orbital septum

Arcus marginalis Inferior orbital rim

Fig. 4.11  Demonstration of the surgical dissection of the infraorbital approach

any dissection into the eyelid, and this will reduce the risk of postoperative entropion significantly (Fig. 4.12). At the beginning of the procedure, lubrication and corneal shield are placed. After that, two traction sutures are placed in the tarsal plate and one through the caruncle using 5-0 Prolene. Care should be taken to protect the inferior puncta. These sutures will significantly aid in the retraction during the procedure. Subsequently, the lower lid is everted gently, and the position of the lower tarsal plate is note; the planned incision should be designed about 5 mm away from the tarsal plate in a curvilinear fashion. Using a needle tip Bovie electrocautery in the setting of 8–10 W, the initial incision is made through the conjunctiva and the capsulopalpebral fascia. Afterward, two Senn or Desmarres retractors are placed gently into the anterior incision margin, and a Seldin or a malleable retractor is placed in the posterior aspect. Once the inferior orbital rim is isolated, blunt dissection with a Kittner or Q tips is used in a twisting motion, and this will displace all the retroseptal fat posteriorly. Once the tissue is thinned uniformly around the incision, the periosteum, arcus marginalis, on top of the inferior orbital rim can be visualized. The incision through the facial aspect of the periosteum, outside the arcus, is done

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4  Surgical Access to Orbital-­Zygomaticomaxillary Fractures

Tarsal plate

Pretarsal orbicularis oculi

Preseptal orbicularis oculi

Orbital septum

Arcus marginalis Inferior orbital rim

Preseptal dissection

Retroseptal dissection

Fig. 4.12  Difference in the position of the incision between the preseptal and retroseptal transconjunctival approach

using a blade or Bovie electrocautery. Following that, the No. 9 periosteal elevator is used to strip the periosteum from the underlying bony structures. Once the rim is completely exposed, the periosteal elevator is positioned vertically to dissect the periorbita from the orbital floor. At this level, the inferior oblique muscle might be encountered, and careful dissection of this muscle is performed to be included with its periosteal attachment. Every effort should be made not to cut or incise through the inferior oblique muscle to prevent postoperative complications. To decrease the likelihood of scar contraction and subsequent entropion, closure of the transconjunctival incision is not recommended. We only perform closure of the periosteum on top of the hardware using 5-0 Vicryl, and then we will align the edges of the incision carefully without suturing it. Finally, the most temporal traction suture is left in place to act as a frost suture and left in place for 24–48 h after the surgery to help in lower lid redraping (Fig. 4.13).

4.3 Preauricular Approach

51

Fig. 4.13  Frost suture for lower eyelid redraping after transconjunctival incision

4.3

Preauricular Approach

The use of the preauricular approach for the OZM fracture is limited for the non-­ comminuted zygomaticotemporal (ZT) suture fracture. Choi K et al. [2]. reported their experience with ORIF of the ZT suture using the preauricular approach. However, all of the cases presented in the article were not comminuted and

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4  Surgical Access to Orbital-­Zygomaticomaxillary Fractures

minimally displaced. In our experience, any comminution in the zygomatic arch that extends to the ZT suture is better approached via a coronal incision. The temporal region around the preauricular incision has multiple important anatomical structures with the facial nerve being at the highest risk of injury at that location. A thorough understanding of surgical anatomy is prudent to prevent injuries to these vital structures. Figure  4.14 demonstrates the different anatomical structures and the path of dissection for the preauricular approach. The skin incision is marked in one of the skin creases anterior to the helix. Posterior digital pressure will identify the proper skinfold/crease. The incision should course entirely along the curvature of the auricle. Local anesthesia with vasoconstrictor is injected to help in hemostasis. Once sufficient time is allowed for the vasoconstrictor

Temporalis muscle TP Fascia

Temporalis Fascia

Line of fusion

Superficial layer

Deep layer

Facial nerve

Zygomatic arch

Fig. 4.14  Anteroposterior view of the preauricular region showing the path of dissection to avoid injury to the facial nerve

4.3 Preauricular Approach

53

to work; usually about 5 min, the incision is made through the skin and subcutaneous tissue. Bipolar electrocautery is used to aid in hemostasis. Temporoparietal fascia is identified next. This layer contains the superficial temporal vessels, and careful protection of these vessels will prevent bleeding. Once the incision is made through the temporoparietal fascia, the superficial layer of the deep temporal fascia is identified. Now the flap should be dissected anteriorly using a No. 9 periosteal elevator to help in retraction and identification of the anatomic structures. Also, this will retract the superficial temporal vessels and the auriculotemporal nerve anteriorly. Starting from superior, the superficial layer of the deep temporal fascia can be easily identified above the arch. Once identified, an incision is made through the superficial layer of the temporalis fascia, and blunt dissection proceeds from superior to inferior toward the zygomatic arch. During this maneuver, the fat in between the superficial and deep fascia will be encountered. Once the zygomatic arch is identified, blunt dissection using No. 9 periosteal elevator is done reflecting the flap anteriorly. The middle temporal vein is usually crossing the zygomatic arch, and careful dissection should be taken to prevent inadvertent injury to the vessel. Once the fracture is identified, a malleable retractor or a Seldon can be used to reduce the fracture segment. One of the significant drawbacks of the preauricular approach is the higher risk of facial nerve injury postoperatively. Although temporary, in most cases, it will increase the frustration of both the surgeon and the patient. We have found that early dissection of the temporoparietal fascia anteriorly will decrease the tension on the flap and reduce the incidence of facial nerve neuropraxia. Recently, a novel preauricular approach was proposed by Qiu et al., and they named it the vascular guided multilayered preauricular approach (VMPA) [3]. In this technique, the dissection will follow the superficial temporal vessels in an attempt to identify and protect the facial nerve. The temporal branch of the facial nerve is located at the level of the condylar neck, crossing superficial temporal vein horizontally. Once the nerve is identified and protected, the rest of the procedure should be carried the same way as described above. The closure is completed in layers, starting with the closure of the superficial layer of the deep temporal fascia. Following that, the subcutaneous tissues are approximated using resorbable sutures, and finally, the skin is closed using monocryl or fast-absorbing gut in a subcuticular fashion. The healing of the preauricular incision is excellent, leaving an inconspicuous scar. (Fig. 4.15). Fig. 4.15  Healing after the preauricular incision

54

4.4

4  Surgical Access to Orbital-­Zygomaticomaxillary Fractures

Coronal Approach

The coronal incision is a very versatile incision that will provide exposure to the upper and midface structures. It provides incomparable exposure to the zygomatic and maxillary bones facilitating superior results. The only drawback would be the scar and alopecia if the incision is designed and performed improperly. The incision should be placed at least 3 cm posterior to the hairline. The more posterior the incision, the less noticeable the resultant scar, but more challenging the reflection of the anterior flap will be. During preparation for the surgery, hair is not removed since there is no evidence of reducing the surgical site infection (SSI) with hair removal [4]. In men, hair is clipped, and in the female patient, the hair is separated into bundles and then twisted and secured in place with elastics. The incision is designed to be parallel to the hairline, extending to the affected side with a slight posterior curvature and then anteriorly connected with the preauricular extension to expose the zygomaticotemporal junction (ZT). Crossing the midline is inevitable even if the fracture is located on one side; this will help in the exposure and reflection of the anterior flap. The incision can be cross-hatched with a knife to make reference marks for ease of closure. Once the incision is marked, local anesthesia with vasoconstrictor is injected to reduce the bleeding. (Fig. 4.16). The incision is initiated from one temporal line to the other, incising through the scalp layers down to the subgaleal plane (Fig.  4.17). This plane is avascular and easily identified by the visualization of the pericranium. The dissection then slightly proceeds in an anterior and posterior direction to allow for the placement of RANEY clips. This step should be performed quickly to avoid excessive blood loss. The use of monopolar electrocautery is not recommended due to the high risk of thermal injuries that lead to postoperative alopecia. Careful application of the RANEY clips and, if necessary, the bipolar electrocautery will control the bleeding. Subsequently, the incision is extended toward the preauricular extension identifying the temporal fascia. Care should be taken to prevent injury to the superficial temporal vessels which lay within this layer. Afterward, the dissection is proceeding anteriorly until a point approximately 3  cm superior to the supraorbital rim (about three Fig. 4.16  Marking of the coronal incision(clinical picture)

4.4 Coronal Approach

55

Blood vessels Subglea

Pericranium

Fig. 4.17  Incision through the scalp layers down to the subgaleal plane. Note the multiple and large subdermal blood vessels

fingerbreadths). The periosteum is then incised and extended laterally to the superior temporal line. Then, the No. 9 periosteal elevator is used to reflect the periosteum down to the supraorbital rim. Care should be taken to avoid injury to the supraorbital nerve, which can be encased in a foramen or passing through a groove. If the nerve is passing through a foramen, an inferior osteotomy is recommended to release the nerve (Fig. 4.18). Attention should be directed now toward the temporalis fascia. The incision should be made at 45 degrees from a point 2.5 cm superior to the lateral eyebrow to avoid injury to the frontal branch of the facial nerve. This branch of the facial nerve runs either on the deep surface of the temporoparietal fascia or within it. This incision is contiguous with the periosteal incision performed in the last step. The dissection is performed in between the superficial and deep temporal fascia and is best performed using No. 15 blade until the superficial temporal fat is seen. This fat separates the superficial and deep temporal fascia. Once the fat is encountered, the dissection should proceed superficial to the fat and that will guide the surgeon to the zygomatic arch. During this step, the surgeon can perform the subperiosteal dissection at the level of the lateral orbital rim to expose the zygomaticofrontal suture; this will help to provide adequate broad exposure to the zygomaticomaxillary complex. Once the arch is identified from the superior direction, the periosteum on top of the arch is sharply incised and dissected from the zygomaticotemporal junction toward the zygomaticofrontal. Performing this step will complete the necessary exposure of all of the zygomaticomaxillary complex junctions. Closure of the incision requires meticulous attention. A proper closure will help achieve soft-tissue suspension over the repaired hard tissues. This is achieved by

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4  Surgical Access to Orbital-­Zygomaticomaxillary Fractures

Fig. 4.18  The release of the supraorbital nerve from the supraorbital foramen to gain more exposure

Fig. 4.19  Suspension of the temporalis fascia and the pericranium

multiple steps including suspension of the orbitozygomatic ligament to the temporalis fascia with nonabsorbable sutures. This step is combined with resuspension of the temporalis fascia itself at a slightly higher level to help further support the soft tissue drape of the face. Following that, the periosteum on the calvarium is approximated (Fig. 4.19). A 10 flat JP drain is inserted into the wound. Subsequently, the surgeon should pay meticulous attention toward the alignment of the incision. Starting with reapproximating of the galea aponeurosis with the use of resorbable

Suggested Readings

57

sutures followed by approximation of the skin edges with staples. For the dressing, we recommend a head wrap with Coban and Kerlix to prevent hematoma formation and reduce postoperative edema. The headwrap should stay for 24  hours and removed the next day after the sugary. The drains should be removed once the output is less than 25 cc over 24 hours.

4.5

Gillies Approach

This approach will provide excellent access to the zygomatic arch and will help in the reduction of the arch utilizing the Rowe Zygoma Elevator. The incision is usually placed 2 cm superior and anterior to the helix of the ear. A 1.5–2 cm oblique incision is made; the incision will pass through the skin, subcutaneous tissues, the temporoparietal fascia, and finally the temporalis fascia. Once the temporalis fascia is sharply incised, the temporalis muscle underneath is identified. A Selden retractor is used to dissect between the temporalis fascia and the temporalis muscle toward the level of the fractured arch. This step will assist in the identification and dissection of the correct plane. Afterward, the Rowe Zygoma Elevator is used to reduce the fracture (do not use the skull as a fulcrum). An audible click is often heard if the arch is reduced and locked into place. To confirm the reduction, sweeping of the blade of the Rowe Zygoma Elevator will ensure the alignment of the medial surface of the zygoma, at the same time, the nondominant hand of the surgeon may be used to palpate the outer surface. Nowadays with the advent of an intraoperative CT scan, surgeons can confirm the position of the zygomatic arch and the quality of the reduction before closure. Closure of the incision is completed in layers, with the closing of both the temporalis fascia and the temporoparietal fascia with resorbable sutures. Finally, the skin can be closed using staples or nonresorbable sutures.

Suggested Readings 1. Strobel L, Hölzle F, et al. Subtarsal versus Transconjunctival approach-esthetic and functional long-term experience. J Oral Maxillofac Surg. 2016;74:2230–8. 2. Choi K, Ryu DW, et  al. Feasibility of 4-point fixation using the Preauricular approach in a Zygomaticomaxillary complex fracture. J Craniofac Surg. 2013;24(2) 3. Ya-ting Q, Yang C, et al. Can a novel surgical approach to the temporomandibular joint improve access and reduce complications? J Oral Maxillofac Surg. 2016;74:1336–42. 4. Tanner J, Norrie P, Melen K.  Preoperative hair removal to reduce surgical site infection. Cochrane Systematic Review, 2011.

5

Fixation Techniques for Stabilizing Orbital-Zygomaticomaxillary Fracture

The purpose of internal fixation is to stabilize bony segments to allow for normal bone healing. The commonly accepted theory of bone healing for facial fractures is fixation osteosynthesis. This concept is a departure from rigid fixation, which represents absolute immobility, and compressive fixation, which represents no gap between the bony segments. The concept is based on normal physiologic fracture healing dependent on vitality, stability, and minimal distance between fractured segments. Fixation plates are available in a variety of conformations and range in thickness between 0.5 mm and 0.8 mm for non-stress-bearing regions of the midface, including the OZM fractures. There are two different categories of plating for the midface, non-stress-bearing midface and stress-bearing midface. In general, the fixation has the lowest profile in the frontal area, and as the fractures progress inferiorly, the plate profile generally increases. This is customary since the inferior aspect of the OZM complex will undergo some tension due to the action of the masseter muscle. Plates should always be aligned along the dense facial buttresses. The buttresses offer cortical bone and greater thickness to allow the fixation screws to engage and retain (Fig. 5.1). For all midface fractures, it is very common to use monocortical plates; therefore, the 5 mm screw length is common along with 1.0 to 1.5 mm diameter screw diameters. It is always ideal to place three screws on each side of the fracture; however, if the placement of three screws requires excessive dissection, excessive retraction, and potential iatrogenic injury, then two screws are more than adequate for midface fracture fixation. Specific to the OZM fracture, the strategy concerning the reduction and fixation of the OZM is variable. On a minimally displaced fracture, only one or two local approaches may be necessary. The intraoral vestibular approach provides Portions of this chapter originally published in Surgical Management of Maxillofacial Fractures (Quintessence, 2019) © Springer Nature Switzerland AG 2020 H. Marwan et al., Management of Orbito-zygomaticomaxillary Fractures, https://doi.org/10.1007/978-3-030-42645-3_5

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5  Fixation Techniques for Stabilizing Orbital-Zygomaticomaxillary Fracture

Fig. 5.1  Fixation plates are always positioned along the dense cortical bone of the facial buttresses

visualization and access to reduce the OZM with a focus on the zygomaticomaxillary junction which includes the orbital rim and the maxillary buttress. Although the vestibular approach does allow for fixation of the infraorbital rim, significant tension of the infraorbital nerve and tissue is required to place screws in a perpendicular manner. However, the right angle screwdriver can be used to achieve proper fixation via an intraoral approach. More importantly, the vestibular access will provide adequate visualization to confirm an appropriate reduction of the complex to the stable bone. In addition to the reduction of the zygomaticomaxillary junction, the zygomaticofrontal and the zygomaticotemporal junctions may be palpated during the reduction to assure the lack of noticeable steps and continuity defects. For fractures that are more displaced or comminuted, more than one junction will require access, and in general, the combination of the zygomaticofrontal and the intraoral and periorbital access to the zygomaticomaxillary junction provides the adequate access for appropriate reduction. In the combination of local approaches, the only component which remains inaccessible is the zygomaticotemporal junction. If the fracture is comminuted or severely displaced, the coronal provides generous access to the zygomaticotemporal and zygomaticofrontal junctions. The main objective concerning the OZM is to reduce the complex against stable bone. As described, there are varying access options to expose the necessary junctions to reduce and fixate the complex to its original preinjury position. Once the appropriate access is gained, the next step involves the manipulation of the complex. Again there are varying strategies involved to gain control of the complex. One

5  Fixation Techniques for Stabilizing Orbital-Zygomaticomaxillary Fracture

61

Fig. 5.2  The use of an intraoral Carroll-Girard screw to manipulate the position of the OZM complex

strategy is the utilization of the Carroll-Girard screw. Much of the literature describes an extraoral incision to fixate the screw and manipulate the complex to the appropriate reduction point. Ideally, however, any additional extraoral incisions should be avoided. The Carroll-Girard screw can be utilized from an intraoral approach. This approach is obviously more difficult due to access but also because the commissure of the lip prevents complete freedom of movement of the complex. To circumvent this limitation, the Carroll-Girard screw should be applied in a vector creating an acute angle against the complex. This allows additional lateral rotation without being limited by the lip. When consideration is given to the common mechanism and resultant medial displacement of the complex, the general vector of reduction would be a lateral rotation of the complex. Care should be taken during the placement of the initial pilot hole to prevent loss of valuable bone surface area so that fracture plates may be placed in an appropriate position (Fig. 5.2). In addition to the Carroll-Girard screw, two additional techniques may be used to manipulate the complex into the appropriate position. One strategy involves the use of a Gillies incision and the placement of Seldin retractor, Brut elevator, or handle of a Rowe disimpaction forceps to replace the complex by applying forces in the appropriate direction based on the direction of displacement. The final strategy that allows manipulation without any additional incisions in the face or scalp involves the use of a curved Kocher or any form of a heavy clamp. The Kocher can be positioned and secured to the anterior aspect of the arch. Due to the curvature of the Kocher, the complex can be manipulated in any vector while avoiding the limitations of the lip commissure. If the Kocher cannot be secured to the anterior aspect of the arch, the Kocher may be clamped shut and inserted in the medial aspect of the arch, and an anterior and lateral force can be applied to the complex to achieve the appropriate reduction.

6

Soft Tissue Management in Orbital-­ Zygomaticomaxillary Surgery

Soft tissue injuries associated with facial fractures are often overlooked. Any facial fracture is associated with some form of soft tissue injury. Improper handling and management of the primary soft tissue injury will result in noticeable scarring and deformity that would be difficult to treat in a secondary setting. In this chapter, types of soft tissue injuries associated with orbital-zygomaticomaxillary (OZM) fractures and their management will be discussed. In addition, intraoperative soft tissue management during surgical approaches will be discussed. The initial presentation for soft tissue injury will vary, depending on the mechanism and the extent of the injury. Once the patient is stabilized following the advanced trauma life support (ATLS) protocol, careful assessment of the wound should be undertaken. A thorough clinical exam with palpation and inspection of the facial wound is prudent to detect the extent of the injury. Any macroscopic contamination would classify the wound as contaminated, and a tetanus booster is recommended if the vaccination history is not known. Physical examination should be performed systematically from head to toe. For the purpose of this textbook, we will focus our examination on the orbital-­ zygomaticomaxillary (ZMC) area. The first area to examine is the periorbital region. Lacerations that extend to the lid margin with fat herniation should be carefully examined to rule out any globe injury, and ophthalmology consultation is warranted in these cases. Following that, the extraocular motility should be assessed. Any ZMC fracture would involve the orbital floor and lateral wall; therefore, any signs of muscular entrapment should be addressed as soon as possible to prevent permanent damage to the muscle. True muscular entrapment will trigger the oculocardiac reflex, leading to syncope, nausea, vomiting, bradycardia, or even asystole. The OZM fracture lies in the cheek subunit, which involves the facial nerve. Any laceration overlying the cheek requires careful examination to rule out damage to the zygomatic and/or buccal branches of the facial nerve. The examination should compare the injured to the non-injured side, and any weakness of the muscle

© Springer Nature Switzerland AG 2020 H. Marwan et al., Management of Orbito-zygomaticomaxillary Fractures, https://doi.org/10.1007/978-3-030-42645-3_6

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movement should be documented. The decision to repair facial nerve injury is based on the location and time of the injury. Surgical exploration/repair is indicated if the laceration is located lateral to a line connecting the lateral canthal tendon to the corner of the mouth. This is due to small size branches and crossover between the zygomatic and buccal branches after that line. On the other hand, timing is essential; facial nerve injury would be easier to repair within 5 days before the distal stump undergoes Wallerian degeneration making the nerve restimulation less predictable. Another important structure is the infraorbital nerve, a branch of V2 of the trigeminal nerve. OZM fractures involving the infraorbital rim almost always involve the infraorbital foramen and nerve, leading to paresthesia around the distribution of the nerve. Careful relief of the pressure during ORIF of the infraorbital fracture will likely result in the recovery of nerve function and sensation within 3 months. The parotid duct is another important structure that is located at the cheek subunit. The duct will follow a line from the tragus to the upper lip cupid’s bow. It follows the buccal branch of the facial nerve up to the anterior border of the masseter muscle, and then it turns medially, piercing the buccinator muscle and opens at the level of the maxillary second molar. Lacerations of Stenson’s duct invariably results in an associated injury to the facial nerve. Penetrating injuries involving the duct should be explored. Cannulation of the duct intraorally with a lacrimal probe can be helpful to locate the injury during the examination. The repair of the duct is necessary to prevent subcutaneous saliva pooling, sialocele formation, or extraoral fistula.

6.1

Type of Soft Tissue Injuries

The most common cause of ZMC fracture is personal violence. Blunt injuries will result in soft tissue contusion and hematoma, affecting mainly the subcutaneous tissues leaving the skin intact. The contusion may result in future fat necrosis and contour deformity. The authors strongly suggest draining any hematoma immediately with a small stab incision to minimize the risk of fat necrosis. Additional types of soft tissue injury include abrasive wounds. This type of injury involves the superficial part of the skin resulting in a dirty wound with embedded foreign bodies and loose devitalized skin. Thorough irrigation, removal of debris, foreign body, and careful debridement with removal of all the devitalized skin will result in adequate healing within 2 weeks. Failing to remove the dirt and the necrotic skin will result in tattooing that would be difficult to treat in a later stage. Wound care is vital in all abrasive injuries. Gentle cleansing with water and the application of non-antimicrobial ointment will assist to hasten the healing process. Lacerations can range from simple puncture and linear to complex, diffuse, stellate, or avulsive lacerations. Assessment of the depth of the laceration is essential. Any deep laceration should be closed in layers, and the smallest number of sutures should be used during the initial phase. Thorough irrigation, removal of debris, foreign bodies, and careful debridement should be completed prior to any closure. If the tissues can be closed without the violation of important structures such as the lower eyelid, revision of the skin edges can be completed in the primary phase to

6.1  Type of Soft Tissue Injuries Fig. 6.1 (a) 65-year-old female presented to the ER with a severe avulsive injury to the left cheek from a bulldog bite. (b) 3-month follow-up after primary closure and cervicofacial advancement flap

65

a

b

avoid the need for a second revision. As general rules, closure of the skin should be performed without any tension, and all the dermal/deep sutures should be buried. Finally, the avulsive injury is rare in association with the OZM fracture. Figure 6.1 shows a case of dog bites to the cheek area that was closed by the cervicofacial advancement flap. This type of avulsive injury is contaminated with different types of microorganisms, including bacteria, viruses, fungi, and mycobacteria. The goal in managing such injury is to decontaminate the site as opposed to aggressive debridement. The preservation of the soft tissue in this location and all of the facial subunits cannot be overemphasized.

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Timing of Repair

Unless the wound is infected and contaminated, primary closure of any facial soft tissue lacerations is closed at the time of injury. Immediate primary closure of the wound will always result in better cosmetic outcomes, may preclude the need for revision surgery, and will improve the patient’s psychology [1]. Open wound care is recommended for infected and contaminated wounds. There is no evidence of the superiority of one technique over the others. However, a wet to moist wound dressing using the Hydrogel gauze or the Hydrogel silver gauze is very effective. A topical antibiotic is used only at the open wound, covered with a non-­ adherent dressing, and the hydrogel gauze is applied on top of the three-layer dressing. The dressing should be changed every 2–3 days for 2 weeks. After that, the wound can be grafted or left to heal by secondary intention. If grafting is planned, all the fibrinous tissues must be removed prior to the placement of the graft into the bed.

6.3

Management of Primary Periorbital Injuries

Simple superficial lacerations of the lower eyelid can be closed primarily with 6–0 fast-absorbing gut or 6–0 Prolene sutures. Full-thickness lacerations involving the lid margin requires the accurate approximation of the lid margin, tarsal plate, and the skin. The gray line of the tarsal plate should be approximated first using a 6–0 PDS suture with the knot tied away from the margin. After that, the tarsal plate is closed using 6–0 absorbable suture with the knot away from the globe to prevent corneal irritation. These two closures should be done carefully without any excessive tension. Too much tension over the cornea can result in corneal irritation. Finally, the skin is closed using the 6–0 fast-absorbing gut or 6–0 Prolene. Injuries to the lateral canthal tendon should be repaired to prevent dystopia. Injuries to the lateral canthal tendon usually involve the underlying zygomaticofrontal suture. Once the bone is repaired, a drill hole is created, and the 6–0 Vicryl suture is placed through the lateral canthal tendon into the drill hole to suspend the tendon. A comparison to the contralateral eye will help in the repositioning of the lateral canthal tendon, and overcorrection is recommended.

6.4

Management of Primary Cheek Injuries

Soft tissue injuries involving the cheek require exploration to confirm the integrity of the facial nerve and Stenson’s duct. Facial nerve injury lateral to the line from the lateral canthal tendon to the corner of the mouth should be repaired as soon as possible. The use of magnification will help in identifying the cut distal branches. The repair can be accomplished using

6.5  Soft Tissue Management during the Surgical Approach

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8–0 Nylon in a tension-free closure. Adaptation of the nerve fascicles can be difficult, and the use of the nerve connector can be helpful as long as the gap between the proximal and distal stumps is less than 5 mm. If more than a 5 mm gap exists, an autologous nerve graft or, more preferably, a cadaveric nerve is recommended for nerve reconstruction. Injuries to the parotid duct require careful assessment of the duct through intraoral cannulation of the Stenson’s duct using the lacrimal probe. Once the distal duct is cannulated, a small cannula is inserted and secured in place using intraoral sutures. The proximal duct is usually difficult to identify; milking the parotid gland can be sometimes helpful to identify the proximal portion of the duct. Once the proximal duct is identified, 8–0 Nylon suture is used to reapproximate the proximal and distal ends over the Angiocath. The mucosa of the lumen should be everted to prevent any stasis of the saliva. The catheter is left in place for 1 month to prevent stenosis of the duct. Figure 6.2 demonstrates a case of the primary repair of the Stenson’s duct. If the proximal ends cannot be approximated, diversion of the flow should be performed. This is done by suturing the proximal duct to the oral cavity using 8–0 Nylon suture. Finally, if the proximal duct cannot be identified, or is damaged beyond repair, ligation of the duct is performed to facilitate the elimination of parotid gland function. Pressure dressing and antisialogogues are usually prescribed to minimize the swelling while awaiting gland atrophy.

6.5

Soft Tissue Management during the Surgical Approach

6.5.1 Coronal Approach During the closure of the coronal approach, the zygomatic retaining ligament should be grasped and suspended superiorly using 2–0 Vicryl suture or 2–0 barbed suture to aid in the suspension. Figure 6.3 shows the location of the facial retaining ligaments. This suspension suture will prevent sagging of the skin in this region, which would create an aged appearance. Passing the needle only through the ligament will eliminate the risk of facial nerve injury. The superficial temporalis fascia then can be closed 1 cm superior to its edge (Fig. 6.4).

6.5.2 Lower Eyelid Approach Closure of any lower eyelid incision should be completed in layers with the suspension of the periosteal layer in order to prevent downward scarring and retraction of the cheek resulting ectropion. Failure to attach the periorbital soft tissues will result in sagging and soft tissue ptosis.

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a

b

c

Fig. 6.2 (a) 56-year-old male sustained a chain saw injury to the right cheek involving the right Stenson’s duct. (b) Insertion of the cannula into the lacrimal probe. (c) Insertion of the cannula into the oral cavity and securing it in place with 4–0 Nylon suture. (d) Primary closure of the wound with tension-free closure. (e) Postoperative picture 6 months after the injury. Note the absence of any salivary fistula, sialocele, or weakness of the facial nerve

6.5  Soft Tissue Management during the Surgical Approach

d

e

Fig. 6.2 (continued)

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70

Orbital ligaments

Buccal-maxillary ligaments

Mandibular ligaments

Zygomatic ligaments

Fig. 6.3  Facial retaining ligaments and the location of the zygomatic ligament

Fig. 6.4  Suspension of the temporalis fascia and the pericranium during the closure of the coronal incision

Suggested Reading

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Suggested Reading 1. Schmelzeisen R, et al. Primary management of soft tissue trauma and nerve reconstruction. In: Ward Booth P, Schendel SA, Hausamen JE, editors. Maxillofacial Surgery: Churchill Livingstone; 2007. p. 231–56.

7

Intraoperative Evaluation during Orbital-Zygomaticomaxillary Surgery

When surgically managing an OZM fracture, there are two components that need to be evaluated. One is the reduction of the complex, and the second is the reconstruction of the orbital wall fractures. With respect to the successful reduction of the complex, the method that most surgeons utilize is the visual evaluation at each fracture junction. The surgeon can assess reduction and bone contact at the ZF junction, the ZM infraorbital rim junction, the ZM maxillary buttress reduction, and the ZT junction. In addition, the ZS junction can also be visualized and used to assess appropriate reduction. The majority of references indicate that the ZS junction is the most effective junction for confirmation of appropriate reduction. The likely reason for this is due to the fact that observation of the ZS junction allows the surgeon to visualize two different planes of the complex, the anterior plane of the ZS junction and the internal orbital plane of the ZS. Thus vertical repositioning via ZF reduction, anterior-posterior positioning, via continuity at the ZF junction, and rotational positioning of the complex via internal orbital wall continuity can all be assessed at this one reference point (Fig. 7.1). Additional methods of reduction confirmation include sequencing. If the ZF is reduced and fixated, then the ZM orbital rim is reduced and fixated, and evaluation of the ZM buttress reveals a well-reduced fracture junction, and then most likely the complex is in the correct three-dimensional position. However, even with meticulous technique and assessment of each junction, due to the presence of four different fracture junctions along with three-dimensional variability of the OZM complex position, the accurate reduction can be deceptive and unpredictable. Minor displacement at fracture junctions, gaps created by comminution, fracture junctions which have resorbed due to delay in surgery, can all lead to errors in positioning. Finally, often times the ZT junction is not visualized due to the unwillingness of the patient or surgeon to perform coronal access of this junction (Fig. 7.2). Portions of this chapter originally published in Surgical Management of Maxillofacial Fractures (Quintessence, 2019) © Springer Nature Switzerland AG 2020 H. Marwan et al., Management of Orbito-zygomaticomaxillary Fractures, https://doi.org/10.1007/978-3-030-42645-3_7

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Fig. 7.1 The zygomaticosphenoid junction for assessment of OZM complex reduction

Fig. 7.2 Postoperative view of nonreduced zygomaticotemporal junction and resultant deficient anterior projection of OZM complex

7  Intraoperative Evaluation during Orbital-Zygomaticomaxillary Surgery

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Other techniques that surgeons often use for assessment is direct visualization and palpation for comparison between affected and unaffected sides. This form of evaluation is definitely limited in its accuracy due to post-injury and intraoperative edema. In addition, if there are bilateral fractures, comparative intraoperative assessment is not accurate. Finally, in regard to orbital reconstruction, the objective is always very clear; replace the bony defect of the orbital floor or medial wall with some form of reconstructive material. The objective of orbital floor/wall repair is the same whether the injury is an isolated defect or one that is associated with an OZM. The surgeon must remove all orbital contents from the adjacent sinuses, and then close the defect with an implant. The result of these two maneuvers is the restoration of orbital volume and globe function. Of utmost importance is the identification of the circumferential peripheral bone of the orbital wall defect. The identification of these borders allows for the appropriate retraction of the orbital contents out of the sinus, and when placing the implant, it assures that the implant is stabilized and supported in all dimensions. To assess if the implant is in an appropriate position, a retractor may be placed inferior to the implant and lifted. If all the peripheral borders of the defect can be visualized, then the surgeon is assured that appropriate reconstruction of the wall defect has been completed. With the advancement in technology though, there have been significant improvements in the ability to assess reduction and reconstruction during the surgical procedure. Two technological advancements which are readily available and utilized are the intraoperative computed tomography scan and the navigation system. The intraoperative CT scan has provided a means to immediately assess the reduction of fractures, facial projection, facial symmetry, and appropriate reconstruction of the orbital walls. The machine is similar to the portable fluoroscope; however, the image quality and view in three perspectives have a significant advantage for the intraoperative assessment of midface fractures. The limitations of the intraoperative CT scan include the need for appropriate spacing in the operating room, as the machine is large. Second, the patient must be positioned so that the head and head support may be positioned within the circular field of the gantry. Finally, time must be allotted so that the radiology technicians can transport the machine to the room, take scout films, and perform the scan. However, with the use of the intraoperative scan, assessment of symmetry, the success of ZM complex projection, symmetry and transverse projection of the zygomatic arches, and success of orbital floor reconstruction can all be completed. This has significant benefits for multiple reasons. First, a postoperative CT is not necessary to assess the surgical reduction/fixation. Second, if there are any discrepancies in ZM complex position, including errors in projection or symmetry, the intervention can be performed without any delay. Finally, with intraoperative CT, confirmation can be made that the orbital implant has been placed in the appropriate position, and an assessment of orbital symmetry can be made with the unaffected side. Often times when reconstructing orbits, the implant is not successfully positioned on the posterior ledge, or the implant is positioned within the ethmoid sinuses or the maxillary sinus. This type of surgical error does not allow the orbital volume to be restored

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and can have consequences to the outcome of the surgical intervention. Therefore, the benefit of intraoperative assessment with a CT can allow the surgeon to modify treatment during the surgery to maximize success (Figs. 7.3, 7.4 and 7.5). The second method, however, not as readily utilized, is the navigation system. The navigation system is frequently used by neurosurgery and skull base surgeons to assist in confirming three-dimensional positioning in real time when visualization is poor and risks are high. This navigation system has applications for the management of the OZM.  Although there is preparation involved when utilizing the navigation system, once set up, a radiology technician is not necessary to assist in the assessment. The first step to utilize the navigation system is to obtain a high-resolution, thin slices CT scan. The scan is then uploaded to the navigation system. Afterward, the surgeon should start the registration procedure of the patient into the navigation system. This is the most important step for intraoperative navigation. The fiducial markers are stable points that can be identified on both the real and virtual patients. These markers can be generally categorized into two types: invasive and noninvasive markers. The invasive markers, fiducial screws, are surgically anchored to the skull before obtaining the preoperative CT scan. The fiducial screws are the most accurate type of markers, but using them requires the patients to have two CT scans done, and they require a surgical procedure to be placed. Fig. 7.3  Image of intraoperative CT scanner

7  Intraoperative Evaluation during Orbital-Zygomaticomaxillary Surgery Fig. 7.4  Intraoperative CT scan showing axial view of symmetric OZM complex projection

Fig. 7.5  Intraoperative CT scan showing coronal view of symmetric orbits and sagittal view of appropriate orbital floor plate position on posterior stop

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On the other hand, the noninvasive makers are either the soft tissues, bone, dental splints, or adhesive markers and do not require two CT scans. Also, the registration procedure can be done fast with acceptable accuracy. The skin surface registration offers excellent application without the need for prior surgery or a second CT scan. However, surgical edema might interfere with the accuracy of the registration. The bony landmarks are considered more accurate, but it requires wider bone exposure to register the bone landmarks. This can be accomplished in complex maxillofacial reconstruction. In summary, there is no ideal registration method, and all of the described techniques have specific advantages and disadvantages. Understanding the limitation of the system will help the surgeon to utilize the best out of navigation as a tool to confirm the proper reduction of the ZMC. The assessment is real time, and there is no additional radiation to the patient. The most significant disadvantage to navigation is that the preoperative CT is the imaging that is loaded, and all mapping is based on the injury CT. Thus if the bones are repositioned and fractures are reduced, the CT image in the navigation will not reflect this. However, if assessing symmetry, or projection, the navigation sensor can be placed on specific points on the reduced complex (i.e., the orbital rim, zygomatic buttress, zygomaticosphenoid junction), to assess if anterior projection has improved, if the lateral projection is appropriate, and if vertical positioning of the complex has improved (Fig. 7.6). Finally, of critical value is the use of the sensor on the posterior aspect of the orbital implant. If an orbital floor fracture has been reconstructed with an implant, the sensor can be placed on the posterior aspect of the implant. If the sensor reveals the position to be on the posterior ledge, then the Fig. 7.6 Navigation system with sensor placed on edge of orbital floor implant

7  Intraoperative Evaluation during Orbital-Zygomaticomaxillary Surgery

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implant was successfully placed. The same technique can be used for all areas of the bone at the periphery of the defect. However, this technique does have limitations, due to the fact that an actual image of the reduced floor or reconstructed orbit is not available. However, the navigation system can be utilized as a real-time guide to assist the surgeon during the process of reduction and reconstruction of the OZM fracture (Figs. 7.7 and 7.8).

Fig. 7.7  Home screen image produced by navigation system revealing green crosshairs in axial, coronal, and sagittal perspectives indicating the location of navigation probe within the orbit Fig. 7.8  Image produced by navigation system revealing green crosshairs confirming position of orbital implant on the posterior stop

8

Postoperative Assessment After Orbital-­Zygomaticomaxillary Surgery

The immediate postoperative clinical assessment has limited value since oftentimes the postoperative edema is greater than the post-injury presurgical edema, and accurate assessment of facial structures and globe position is difficult to determine. In addition, even with functional deficits, postoperative edema may limit the assessment of entrapment and trismus. Therefore a postoperative CT is essential in the assessment of appropriate facial bone reduction. With the benefit of accompanying analytical software, multiple accurate measurements can be made on the CT to assess for facial symmetry and reestablishment of projection and pre-injury contours. The objective of postoperative imaging involves the analysis of surgical success to restore facial fractures to the preinjury state. The short-term benefit of the CT and the associated 3D reconstruction is the immediate assessment rather than the “wait and see” approach of the clinical examination. If an appropriate reduction is achieved with the adequate restoration of projection and symmetry, the patient can be notified of the successful results and anticipate an acceptable outcome. Conversely, if the reduction is inadequate or the orbital floor plate is inappropriately positioned, the patient may undergo immediate modification to remedy the less than ideal results. Due to the severity of many of the fractures encountered, and since patients do not customarily have baseline intact CT scans of their faces, an evaluation of symmetry to the contralateral aspect of the face represents the best means to assess appropriate fracture reduction. Four measurements can be made on a CT: linear distance, angle measurement, surface area, and extrapolated volume. Multiple aspects of the face can be assessed using these four tools of measurement: anterior facial projection, transverse facial projection, enclosed areas of the face (orbit, infra zygomatic space), and orbital volume (Fig. 8.1).

Portions of this chapter originally published in Surgical Management of Maxillofacial Fractures (Quintessence, 2019) © Springer Nature Switzerland AG 2020 H. Marwan et al., Management of Orbito-zygomaticomaxillary Fractures, https://doi.org/10.1007/978-3-030-42645-3_8

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Fig. 8.1  Combination of linear, angular, and surface area measurements can be utilized to analyze the character of an OZM fracture both before and after the surgical intervention

Fig. 8.2  Clinical view of postoperative enophthalmos

Facial projection is an important component of successful facial bone reduction. With the understanding of force transmission on the face, any blunt trauma propagating posteriorly will lead to the posterior displacement of the OZM complex. The posterior displacement at these buttresses leads to deficiency in anterior projection and a loss of vertical height and also results in an increase in orbital volume. Any displacement of the orbital rim will lead to projection deficiencies and direct increases in orbital volume. In addition, as the rim is affected, the floor and/or medial wall is also affected, and thus there is a significant increase in orbital volume. This altered orbital volume, which can be as little as a 6.3% increase, may lead to the retraction and inferior displacement of the globe and thus the clinical manifestation of dystopia and enophthalmos (Figs. 8.2 and 8.3).

8.1 Assessment

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Fig. 8.3  Coronal CT image of same patient revealing discrepancy of postoperative orbital size

8.1

Assessment

8.1.1 Linear Measurements Although the facial skeleton is a three-dimensional structure, specific factors such as anterior and lateral projection directly influence the surgical and esthetic outcomes. When assessing a preoperative or postoperative CT, a direct measurement can be made on an axial or coronal image to determine both the degree of fracture displacement on preop CT scans and the success of reduction on the postop CT scans. Looking at an OZM, the position of the complex can be evaluated on an axial CT using the Frankfurt horizontal as the plane of reference. In this plane, the posterior displacement of the complex and lateral displacement of the arches can be measured and compared to the contralateral side. Measurements of lateral arch displacement can be made using the midsagittal plane as the fixed midline reference. Additional anterior-posterior measurements can be made using a fixed skull base reference which exists on both sides of the midline such as the carotid canal or the posterior aspect of the glenoid fossa. Although the measurements cannot be directly translated into the surgical intervention, evaluation of the preoperative position of the fractures segments would assist the surgeon in determining the access needed and the degree of manipulation required for appropriate reduction. For the postoperative evaluation, the same lateral A-P and lateral measurement can be made to assess the successful reduction of facial fractures (Fig. 8.4).

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Fig. 8.4 Postoperative axial CT image with a linear measurement tool to assess the symmetry of the transverse dimension of the zygomatic arch and anterior projection of OZM complex

8.1.2 Angle Measurements In addition to linear measurements, angles can also be measured to determine surgical plans and assessment of surgical results. There are multiple facial angles that have been assessed in order to assist in achieving optimal results in trauma management. The first involves the angle created between the anterior wall of the maxilla and the orbital floor in the sagittal plane. Orbital floor reconstruction is a difficult procedure especially in combination with an OZM fracture. The dissection necessary to establish support for the alloplastic implant is tedious and when areas of support are missing, the implant must be cantilevered to achieve the appropriate support for the globe contents. In general, the inclination from the anterior wall of the maxillary sinus to the posterior shelf of the orbit measures an approximate 90° angle. Like all anatomy, there is always variability, and without the appropriate CT study of a large number of anatomic specimens, the 90° reference would only represent a recommendation. However, when reconstructing an orbital floor with minimal support for the implant, being aware that the orbital floor must be reconstructed with at least a 90° inclination will allow the surgeon to reconstruct the orbital floor in a more accurate position. The second set of relevant angles which can be measured on the CT scan involves the zygomatic arch and any fractures involved with the arch. The zygomatic arch directly affects the transverse dimension of the face. When a patient sustains an OZM fracture, the arch or zygomaticotemporal junction is always affected. Due to the arcuate form, there is often telescoping and lateral displacement of the arch. First, if the zygomatic process of the temporal bone is fractured, there will be a flare to the posterior aspect of the arch. This flare will invariably lead to a widening of the face, and the greater the angle of displacement, the greater the lateral displacement of the complex based on the length and anterior extension of the zygomatic arch (Fig. 8.5). The second angle which can be measured on the arch is the transition between the posterior and anterior aspect of the arch. The zygomatic arch tends to

8.1 Assessment

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Fig. 8.5  CT image with an angular measurement tool to assess the degree of displacement at the sagittal fracture of the temporal process of the zygomatic bone and the resultant linear transverse displacement

be more linear than it is initially perceived during the reduction and fixation process. The posterior third section of the zygomatic arch extends laterally, and as the arch extends anteriorly, a 120° angle is created as it comes together with the maxillary buttress. If this angle is not preserved and a general curve is placed on the arch during fixation, the transverse dimension will be inaccurate, and the patient will manifest with a widened appearance of their midface.

8.1.3 Surface Area The next measurement which can be obtained from the CT scan is surface area. Surface area measures are not as critical in preoperative assessment however offers more benefit when determining the accuracy of postoperative reduction. The surface area can be calculated for confined areas of the facial skeleton such as orbits and has been commonly used for lesions and pathology in the head and neck area. The surface area on a CT is calculated based on the delineation of a region of interest. Once the region is defined, the pixels are counted within the region, and an algorithm converts the pixels to square centimeters. The surface area is complicated by the limitation of its benefit. For any given enclosed space, if a certain dimensional aspect is reduced while another is increased to the same degree, the absolute surface area will not change. The most ideal manner in which surface area is truly informative is if the two areas are overlaid on each other and observations are made to determine the location of the variability. There are two areas that can be assessed when determining the success of postoperative reduction. One involves the reconstruction of the periorbital framework for a midface fracture. By assessing the surface area of the anterior orbit, the

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Fig. 8.6  The use of surface area comparison to facilitate the evaluation of asymmetry of the orbits

surgeon can determine if the framework was reestablished (Fig. 8.6). In the event that the patient develops a dystopia postsurgery, if the framework is appropriately reestablished, a determination can be made to modify the floor component. However, if the framework is not reduced appropriately, then the inadequacy would be related to both the reduction of the complex and the orbital floor. The second area which can be measured involves the intra-arch space or the area defined between the temporal bone and zygomatic arch. This area is directly related to the position of the zygomatic complex and the fractured arch. For unilateral fractures, the analysis of this area can assist in determining any alteration of complex position or error in the reduction of the arch form. The analysis is based on the contralateral unaffected infra-zygomatic space (Fig. 8.7). Although the surface area value can be determined using pixel counts and algorithms, an overlay process is a simple method in determining the area in which the complex has deviated in its positioning and whether the angles of the arch were reestablished.

8.1.4 Volume The volume of the orbit is the last postoperative assessment tool that can be used to assess surgical success. The orbital volume is calculated based on the use of a series of coronal CT slices. For each CT slice, the image of the orbit is isolated and the surface area is calculated based on pixel counts. A volume is then calculated based on the width of each CT cut and the surface area which was isolated from each image. Orbit volume is obtained from both the affected and unaffected side of the patient and a comparison can be made as to the effectiveness of the orbit

8.1 Assessment

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Fig. 8.7  The use of surface area comparison to facilitate the evaluation of asymmetry of the infra-­ zygomatic space

reconstruction. Volumetric comparisons are most useful for isolated orbital wall or floor fractures since only one variable is considered. Although volumetric measurements can be made for OZM fractures, as mentioned previously, multiple variables including complex positioning in varying dimensions and wall/floor reconstruction can affect the absolute volumetric measurement. As the surface area measurement though, the measured volume is not able to isolate subtle discrepancies in orbital floor reconstruction or complex position. Hypothetically, the calculated postoperative orbital volume of the affected side may vary less than 1% from the unaffected side, and the surgeon may presume that the reconstruction was ideal. However the complex may be in an inappropriate position in which one dimension may be medially displaced while another component is laterally displaced but since the displacement cancels each other, the calculated volume appears to be ideal. This is a subtle but notable limitation of the volumetric assessment of the orbits.

8.1.5 C  omparison of Preoperative and Postoperative 3D Reconstruction Finally, comparing preoperative and postoperative 3D CT reconstruction is a very useful tool in evaluating overall symmetry. With the 3D image, overall contour symmetry, orbital rim symmetry, and transverse width can be quickly observed. In addition, the overall success of reduction can easily be assessed by evaluating the change

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in complex positions between the preoperative and postoperative views. Of course, all the postoperative imaging is irrelevant if the clinical appearance and function of the patient were not optimized from the OZM reduction. However, in general, if the OZM was successfully reduced to its original position, the patient will likely achieve an acceptable level of facial projection and symmetric globe position (Fig. 8.8a, b).

a

b

Fig. 8.8 (a, b) Comparison of 3D reconstruction assessing OZM complex reduction, projection symmetry, and orbit symmetry

9

Complications Associated with  Orbital-­Zygomaticomaxillary Surgery

Failure to achieve the desired outcome: 1. Projection. 2. Orbital reconstruction.

9.1

The Failure to Achieve the Desired Outcome

The first category of complication in the management of facial fractures is the failure to achieve the anticipated goal of proper reduction. The second category of complications is those resulting from the management of the injury or iatrogenic injury. The third category is wound healing issues. It is important to understand this distinction in order to assess postsurgical results accurately, understand the cause and effect of surgical actions, and improve upon them. It would be impossible to avoid all complications, but it is important to always strive for optimum results. There are two phases that may lead to failure in achieving desired results. The first phase is the planning stage and the second is execution. Planning will include data gathering including clinical and radiographic assessment. At this stage, if specific information is not included in the plan, or there is an underestimation in the significance of a specific component of the injury, the outcome may not be satisfactory. Specifically, for the OZM fracture, the two most common planning errors involve the ZT junction and the reconstruction of the orbital floor. In regard to the ZT, the greatest underestimation involves the necessity to expose and fixate this junction. The primary reluctance to access this junction is that it is only accessible via the coronal approach. With this generous incision, the eagerness and

Portions of this chapter originally published in Surgical Management of Maxillofacial Fractures (Quintessence, 2019) © Springer Nature Switzerland AG 2020 H. Marwan et al., Management of Orbito-zygomaticomaxillary Fractures, https://doi.org/10.1007/978-3-030-42645-3_9

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Fig. 9.1 Postoperative OZM fracture axial CT image revealing an inadequate reduction of the zygomaticotemporal junction leading to deficiency of anterior projection

motivation to open this junction diminish. Therefore errors in planning involve overlooking the fracture of the ZT including the sagittal fracture or the election not to stabilize this junction. The consequence of the ZT overlook is the inaccurate anterior projection of the complex or widening of the face. Details regarding the necessity to expose and fixate this junction are elaborated in the Planning chapter of this text (Fig. 9.1). The second area which is often poorly planned is the reconstruction of the orbital walls. When assessing the orbital component of the OZM complex fracture, the surgeon must consider that the OZM complex may be displaced, which would lead to an inaccurate assessment of the orbital floor defect. Since the complex will be manipulated, the orbital floor defect may become smaller as the bony segments are reduced. In addition, if there is rotational displacement, whether it be in the axial axis or coronal axis, there may be a significant effect on the orbital floor. In addition, frequently a defect or comminution may appear minor on the CT scan; however, when accessing the area, the fractures/comminution/displacement always are more complex than initially appeared. Thus, generally speaking, a surgeon should assume that every orbital floor requires reconstruction after the OZM complex reduction. After the OZM is reduced, either an intraoperative CT may be obtained to confirm the necessity of reconstruction or dissection can proceed in which direct visualization of the size and displacement of the defect can determine the necessity to intervene. As with isolated orbital floor and medial wall injuries, any time an orbital floor defect of significant size is not reconstructed, there will be resultant cosmetic defects and potential restriction of globe motility (Fig. 9.2). The second phase which may lead to failure to achieve desired results is the execution. For all facial fractures, the failure to achieve appropriate reduction will always have some manifestation of either appearance or function for the patient. Some areas of the face do not have a direct effect on function, whereas other areas

9.1  The Failure to Achieve the Desired Outcome

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Fig. 9.2 Postoperative coronal CT image revealing an inadequate reconstruction of an orbital floor defect leading to persistent diplopia

have little effect on appearance, but mostly on function. Logically speaking, outside of soft tissue injuries overlying the fractured facial skeleton, when the bones are reduced appropriately, all function and appearance should be restored to the pre-injury state. However, to achieve such a perfect reduction is not always straightforward. There are many factors that work against the ideal reduction of bone. The first is the accessibility of facial fractures. All facial bones are enveloped in soft tissue, these soft tissues have a direct effect on the appearance of a patient. Unlike other services that manage bone throughout the body, there is no direct access to facial fractures. Care must be taken to access fractured bone within hairlines, eyebrows, and rhytids and in areas that will remain inconspicuous after the soft tissues heal, such that the patient and all others will have a difficult effort to recognize their injuries. In addition, within this soft tissue envelope, there are important structures including muscles and nerves. The infraorbital nerve, the supraorbital nerve, the inferior alveolar nerve, the branches of the facial nerve are always present and, regardless of facial fractures, must always be preserved. Since the entire facial skeleton is covered with facial musculoaponeurotic layer, these muscles must be respected, and care must be taken to resuspend them, and reapproximate cut ends to preserve the normal symmetric animation of the face. Finally, the presence of the globe limits the freedom to expose and manipulate the periorbital framework, and the presence of the nose, ear, and teeth all affect the ability to access the bone. Another factor is the visualization of the fractures. As mentioned above, accessibility is limited by the potential for facial scarring and vital structures of the face. However, even when the fractures are accessed with the best possible access method, fractures are not fully visible from all perspectives. If a mandible fracture is exposed via a standard intraoral approach, the lingual aspect is not visualized. If a lateral

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brow approach is used, for the management of the ZF process, the ZS may be visualized; however, the lateral aspect of the ZS will not as it is covered by the temporalis muscle. Over history, surgeons have refined these access techniques; therefore access techniques utilized at the current time are adequate to achieve good results. However, there will always remain a slight margin of ambiguity as to the entirety of fractured bone and the stable points of fixation are never fully visualized. The third major factor that affects the successful reduction of facial fractures is the degree of injury. If the bone is fractured and remains non-displaced, surgical intervention is not necessary and the patient will heal well. However, if there is severe comminution at the fracture, or if there are multiple concomitant facial fractures, the ability to reduce the facial fractures becomes much more difficult. The greater the distance between fractured segments to stable bony references, the greater the margin of error in the appropriate reduction. If the medial aspect of the infraorbital rim is stable, the reduction of the OZM will be accurate. However, if the medial aspect is part of a concomitant NOE fracture, the distance between the OZM to stable medial bone has now increased and appropriate projection becomes less predictable. Fortunately, the majority of facial fractures that arise in the ER via blunt trauma do not present with severe comminution or multiple concomitant fractures; therefore, reduction is more straightforward. Thus the combination of these three limitations leads to complications associated with failure to achieve the desired outcome. The lack of access, limited visualization, and severity of fracture essentially lead to three major manifestations of failure to reduce. The first is the projection. Almost all traumatic injuries lead to a collapse of the bone and loss of bony projection since force is directed in a posterior or lateral vector. Whether projection refers to the anterior projection of the maxillary buttress or the accurate restoration of the transverse width (zygomatic arch), any time there is an alteration of projection, there is a loss of symmetry, leading to a noticeable deformity of the face. The second manifestation of failure to achieve the desired outcome pertains to the orbit. For any fracture associated with the periorbital framework and orbital walls, the volume of the orbit is increased. This increase leads to enophthalmos and dystopia (Fig. 9.3). In addition, if the orbital walls are fractured, oftentimes there is entrapment of periorbital tissues which can lead to diplopia. The primary objective when referring to periorbital fractures is to restore periorbital architecture to the pre-traumatic state, the restoration of orbital volume, and the resolution of any entrapment. If the architecture is not restored to the pre-traumatic state, the volume will never be restored. if the periorbital structures are restored, but the orbital wall defects are not properly reconstructed, again the volume cannot be restored. The restoration of globe motility is dependent on the release of any entrapped periorbital tissues and imperative when appropriately reconstructing the orbital walls. When the surgeon is not successful in restoring orbital volume, whether it is due to the inaccurate reduction of the periorbital framework or reconstruction of the periorbital walls, the cosmetic deformities of the globe position along with potential restriction of globe motility are maintained. This leads to asymmetry of the face and less than ideal outcomes (Fig. 9.4).

9.2  Iatrogenic Complications: Access-Related Complication

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Fig. 9.3  Postoperative 3D CT reconstruction revealing an inadequate reconstruction of the periorbital framework and orbital floor defect leading to dystopia and enophthalmos

Fig. 9.4  Clinical image of a patient with inadequate periorbital framework reduction and orbit reconstruction. Patient with persistent diplopia, dystopia, and enophthalmos

9.2

Iatrogenic Complications: Access-Related Complication

The complexity of the OZM fracture is based on the involvement of four different bony processes that define the fracture. The difficulty of the management depends on displacement and comminution at the four different bony processes, along with the three-dimensional variability and instability of the complex. This instability of

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the complex generally corresponds to the severity of the injury. Therefore, the greater the severity of the injury, the more unstable is the complex, the greater the soft tissue injury, and the more access and visualization required for appropriate reduction and management. The more soft tissue injury, and the more approaches required to access the processes of the OZM, the more likely an iatrogenic injury will occur during the management of the fracture.

9.3

Fixation Plate Exposure/Sensitivity

Two locations are more prone to fixation plate exposure/sensitivity: the intraoral and the transconjunctival areas. Intraoral exposure of the fixation plate can occur due to the inappropriate design of the incision, especially with edentulous patients who wear denture prosthesis. During the exposure of the ZM suture in the edentulous patient, placing the incision at the depth of the maxillary vestibule will often lead to subsequent exposure of the fixation plate from the continuous pressure from the denture flange. Therefore, the recommended incision in any edentulous patient is a mid-crestal incision to avoid this complication. Intraoral fixation plate exposure is frequently a late complication, and removal of the plate is inconsequential since the bone usually has healed by the time the plate becomes exposed. Sensitivity from the miniplate in the area of the infraorbital rim is not uncommon. Careful closure of the periosteum, as described in the surgical access chapter, is prudent; this adds an additional layer of soft tissue to insulate the plate from palpability and potential sensitivity. Additional considerations for fixation plate selection include profile size and location along the infraorbital rim. Since the infraorbital rim is a non-stress-bearing location, and oftentimes there is comminution in this area, a very low profile malleable plate such as a 0.4 mm or 0.5 mm profile is recommended. In addition, when placing the plate, the plate should be placed inferior to the most palpable area of the rim. The more inferior the plate, the less palpable and the more soft tissue coverage that is available to insulate the plate.

9.4

Neurosensory Disturbances

Paresthesia after ORIF of the ZMC fracture is common. For neurosensory deficits, it is critical to assess and document the patient’s status prior to any surgical intervention. Nerve injury is not uncommon when the fracture of the OZM propagates through the infraorbital foramen. In addition, if there is a medial displacement of the OZM complex, the nerve may be compressed from the injury. Traditionally, increased postoperative paresthesia or anesthesia is related to a traction injury (neuropraxia) of the infraorbital nerve. Neuropraxia to the infraorbital nerve can occur during retraction of the facial flap to dissect and visualize the infraorbital rim, during manipulation of the OZM complex, and retraction during the placement of the fixation plates. Due to the nature of the intraoperative retraction injury without transection, any intraoperative injury and postoperative manifestation resolve within

9.6  Eyelid Malposition

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3 months. However, if there was additional injury prior to the surgical intervention, this time frame may be prolonged. Therefore, careful identification of the nerve and gentle retraction are mandatory to reduce the incidence of iatrogenic injury. Patients will often complain of paresthesia to the lower eyelid, lateral nasal wall, and upper lip. Postoperative neurosensory testing and documentation are important. If the postoperative images reveal impingement of the nerve, removal of the fixation plate and repositioning may be recommended to avoid painful traumatic neuroma formation.

9.5

Alopecia from Coronal Incision

Liberal use of electrocautery will result in loss of hair follicles and subsequent alopecia. This is problematic especially in short-haired patients in which the scar line cannot be covered by hair (Figs. 9.5 and 9.6). The use of local anesthetic with vasoconstrictor and the efficient application of Raney clips will assist in controlling any hemorrhage during the initial scalp incision. Avoidance of all monopolar electrocautery and limited use of bipolar electrocautery is recommended to avoid this complication.

9.6

Eyelid Malposition

Lower eyelid complications after surgery can be challenging and frustrating for both the surgeon and the patient. Therefore, careful selection of access type and meticulous surgical technique are the most important factors associated with the prevention of these complications. Ectropion can be prevented by avoiding the lower eyelid skin incisions. The highest incidence of postoperative ectropion is associated with the subciliary incision. The use of transconjunctival incision is recommended for all of the access to the periorbital areas. Fig. 9.5  Superior and lateral view after coronal incision, demonstrating the alopecia

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Fig. 9.6  Superior and lateral view after coronal incision, demonstrating the alopecia

Fig. 9.7  Lower eyelid entropion following a lower lid iatrogenic laceration during fixation of the miniplate

The transconjunctival approach is not without complications. Entropion is the most egregious complication associated with the transconjunctival incision. The cicatricial entropion will result in turning the eyelashes inward with subsequent ocular discomfort, trichiasis, corneal abrasion, keratitis, and visual loss (Fig. 9.7). The cause of the entropion is likely related to the scar/contracture of the internal

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layers of the lower eyelid lamella. This can occur if the initial dissection of the conjunctiva/capsulopalpebral ligament/periosteum is not performed in a meticulous fashion. However, specifically relating to the OZM, if the infraorbital rim is not reduced to the appropriate anterior and superior position, contracture may occur in which there will be an inward and inferior rotation of the septal attachment at the rim and resultant entropion. In addition to the meticulous technique of the transconjunctival access, two additional intraoperative considerations may assist in preventing the entropion. The first involves retraction of the eyelid during manipulation of bone and application of the fixation plate. Gentle retraction of the lower lid is of paramount importance. If access is limited, a transcaruncular extension for the medial aspect or a lateral canthotomy may be performed for increased lateral access. In addition, the access incision may be transferred from one location to the next; the entire rim and plate do not have to be visualized when positioning the plate or placing the screws. The plate may be positioned, and when inserting medial fixation screws, the access incision may be transported to the medial aspect, and when placing lateral screws, the incision may be retracted toward the lateral rim. Overzealous retraction by the assistant is not uncommon, and when manipulating the lower eyelid, especially at the fragile medial aspect, lacerations may occur. The second consideration involves the position of the OZM complex during the transconjunctival access. If there is significant displacement of the complex in a posterior or inferior dimension, transconjunctival access is difficult due to the distance between the lid conjunctiva and the position of the displaced bone. One strategy involves accessing the ZF junction, and the ZM junction, and then taking the complex and manually reducing it so that the rim is positioned in a more ideal position. By performing this maneuver, the surface of the conjunctiva and the rim are in a more ideal and identifiable position such that transconjunctival dissection proceeds in a more straightforward manner and the incidence of entropion is reduced.

New Advances in the Planning and Management of Orbital Zygomaticomaxillary Fractures

10

When referring to advances in the management of the orbital zygomaticomaxillary fractures, there are several categories that may be discussed. The first is the preoperative assessment and virtual surgical planning. The second is patient-specific custom guides and fixation plates, and the third is the intraoperative assessment. All technological advances are based on the improvement of imaging. The speed in which CT imaging is now acquired, the convenience of having CBCT technology in an outpatient office, the fine cut CT with the fine anatomic detail has changed the manner in which surgery is performed. The days in which plain films were used to plan orthognathic surgery and manage trauma and the days in which the CT imaging was placed on large sheets of film made it difficult for the surgeon to understand and anticipate the true topographical anatomy of the facial contours. With relevance to facial trauma management, the three perspectives of the traditional CT including axial, coronal, and sagittal cuts, are adequate for identifying facial fractures and establishing a diagnosis. In addition, they are also effective for determining displacement and comminution. However, assessing one cross-sectional view to the next does not provide the surgeon with the global view of the entire injury. With CT technology, a detailed 3D rendering of the patient’s facial skeleton can be reproduced and evaluated. This 3D reconstruction provides a comprehensive perspective that allows the surgeon to visualize and anticipate the injuries that would be encountered once the soft tissues are reflected. It is the best representation of facial fractures. With this CT data, computerized applications have been developed to take the 3D image and allow the surgeon to perform virtual surgery and print 3D models. Virtual surgery based on 3D reconstruction provides information that was not as readily available in the past. The ability to view the skull and the facial skeleton from all perspectives, the ability to perform the surgery and assess for bony interferences, and the ability to assess osteotomies and their relationship to important anatomic structures including tooth roots, nerve canals, and orbit structures are all information that could not be obtained easily before the advent of virtual surgical planning. Finally, bringing a patient-specific 3D model will help the surgeon to visualize the

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fracture in real time and will help in bending and fixating the plate at the best anatomical position (Fig. 10.1). Once the surgery is deemed feasible by VSP assessment, then surgical guides can be fabricated that assist the surgeon in determining the location of osteotomies, the movement of bone, and the final anticipated position of that bone. Finally, with the same 3D rendering, patient-specific custom implants can be fabricated which act as both a surgical guide and perfectly adapted fixation plates (Figs. 10.2, 10.3 and 10.4). There are many advantages this technology offers to both the surgeon and the patient. From the surgeon’s perspective, virtual surgical planning provides an incredible insight into the anticipated surgery. The custom cutting guides, surgical Fig. 10.1  3D model of corrected post-traumatic OZM deformity. The model can be used to pre-bend the plates

Fig. 10.2  The use of a patient-specific implant to reconstruct the orbital floor and restore the orbital volume

Fig. 10.3  The use of the PEEK implant in the secondary reconstruction of the left orbital floor defect

10  New Advances in the Planning and Management of Orbital Zygomaticomaxillary… 101 Fig. 10.4  The use of the PEEK implant in the secondary reconstruction of the left orbital floor defect

splints, and custom plates represent an incredible tool to increase the accuracy of cuts, movements, and positions. In addition, there is a significant increase in the efficiency of the procedure. All the advantages that VSP technology offers are then transferred to patients via a reduction in complications, decreased general anesthesia time, and improved surgical outcomes. Unfortunately, there are a few disadvantages associated with these technological advancements. These include an increase in cost, sterilization concerns, additional needs for software, hardware, manufacturing hardware, and fabrication time (Fig. 10.5). However, the greatest disadvantage is the reliance on technology by the surgeon. The use of VSP with patient-specific guides and plates precludes the need for the surgeon to have any plate bending skills. In addition, the use of patient-­ specific guides and implants is not without some variability. If the guides are not appropriately positioned, or if the surgical plan changes, without traditional surgical plate bending skills or problem-solving skills, the surgeon may struggle to resolve any unexpected intraoperative patient-specific implant-related inconsistencies. Most of the CAD/CAM technology is utilized during elective cases. Unfortunately, trauma patients, including the OZM fractures, require early treatment to achieve the most ideal results and prevent significant soft tissue scarring. Therefore, the CAD/ CAM is extremely useful in the diagnosis and planning of secondary reconstruction

102 10  New Advances in the Planning and Management of Orbital Zygomaticomaxillary… Fig. 10.5  A starch model that cannot be sterilized. The model has to be wrapped in a sterile plastic bag before it can be used for plate adaptation

cases and delayed OZM repair. The VSP can be utilized for the creation of the osteotomy of the secondary defect, fabrication of custom cutting guides, creation of custom plates, and the creation of the 3D models that can be utilized for pre-bending plates. In addition, malocclusion can be addressed with the use of an intraoral laser scanner system or topographic occlusal imaging that can be uploaded to the interactive 3D virtual model. The standard workflow for the application of the VSP includes: 1. Acquisition of high-resolution, thin slice (1.5 mm) cut, maxillofacial CT scan without IV contrast. 2. Conversion of the CT scan data to DICOM format. 3. Creation of the 3D craniofacial skeleton. 4. VSP teleconference (web meeting) with the biomedical engineer for the preoperative planning session. 5. Creation of the required adjuncts including the 3D model, custom guides, and/ or plates. The conversion of the CT scan to DICOM format and the creation of the 3D craniofacial skeleton can be made by the manufacturing company or by the surgeon if the surgeon has an in-house 3D printer.

10.1 In-House 3D Printing An additional advancement that may assist in the management of the OZM is an in-house 3D printer. As mentioned in the earlier, assessment of the injury and simulated surgery can be performed using VSP software. This rendered image is then

10.2  Intraoperative Computed Tomography

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Fig. 10.6  In-house printed 3D model from polylactic acid (PLA) biodegradable material

utilized to fabricate patient-specific guides and implants. This requires fabrication via milling or printing. Therefore the majority of these cases must go to an outside service due to the milling and printing machines. However, the use of in-house printers is becoming more popular. A hospital or clinic may invest in a 3D printer in which the upfront cost will be higher; however, accessibility and efficiency will increase. At the current time, the main advantage of an in-house printer would be the fabrication of a 3D stereolithographic model. The model can be fabricated based on the CT imaging of the facial fractures. A 3D model will offer excellent views and understanding of the injury. If the appropriate software is available, then virtual surgery may be performed, and a new model may be fabricated based on the corrected position of the fractures. On this model then, plates may be prebent and sterilized so that they can act as both a guide for reduction and a plate for fixation. The plates would be patient-specific prebent stock plates but would not be prefabricated by the 3D printing or milled process (Fig. 10.6).

10.2 Intraoperative Computed Tomography The second category of advancements is intraoperative assessment tools. In the past, there was no reliable method of assessing accurate bone reduction when managing the OZM fracture. Essentially the two indicators that the bone was reduced in the correct position were the alignment of the bone junctions and a visual comparison of symmetry between the unaffected and affected sides. The problem with these two methods of assessment is that they may be inaccurate. Regarding bone alignment, since the majority of OZM fractures are managed with local approaches, the zygomaticotemporal junction always remains hidden and potentially displaced. Even though the alignment of three junctions will generally provide accurate positioning, if there is any comminution, limited visibility, or adjacent concomitant fractures, alignment of the bone can be achieved without complete accuracy of positioning. In addition, visual assessment of symmetry is even more unreliable due

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to the fact that soft tissues are often edematous post-injury and become more edematous during surgical manipulation. With the alteration of soft tissue volume, a displaced OZM complex may be posteriorly displaced, but with edematous soft tissues, the projection may appear very symmetric. Unfortunately, once the edema subsides, there may be a noticeable discrepancy in projection. The development of intraoperative CT scanning has now provided a very accurate assessment of fracture reduction. The concept of intraoperative imaging is common in orthopedics as fluoroscopy has been used extensively in the past and continues to be used today. However, aside from isolated arch fractures, fluoroscopy is somewhat limited in assessing OZM complex reduction, orbital volume, symmetry, and projection. Thus, with the development of a portable CT unit, intraoperative CT scanning became accessible. Although the resolution is inferior to the standard medical fine-cut CT scan, the intraoperative CT provides all the necessary radiographic information to determine accurate reduction, complex positioning, facial symmetry, orbital symmetry, and accurate implant placement. If there are any discrepancies in symmetry, insufficient projection, or a malpositioned orbital implant, immediate modifications can be made. This represents a true benefit to patients with improved surgical outcomes, reduced incidence of surgical take backs and revisions, and reduction of unnecessary postoperative radiation. One main disadvantage of the O-arm is the availability of the machine and the time consumed for acquisition. One study has found that the mean scan time to be 14.5 min on average [1]. However, the investment of time and resources in obtaining the intraoperative scan is less than taking the patient back to the OR for a revision. To increase the efficiency and allow for a better image, we recommend the following (Figs. 10.7 and 10.8): 1. Contact the radiology department before the OR and request the O-arm at the time of posting. 2. Place a radiopaque headrest at the beginning of the case.

Fig. 10.7  The use of intraoperative CT scan

Suggested Reading

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Fig. 10.8  The use of intraoperative CT scan

3. Remove all the metal from the face and keep the head in midline and neutral position. 4. Cover the patient with a sterile drape and mark the midline. 5. Communicate with the technician regarding the area of interest (orbit, maxilla, mandible).

Suggested Reading 1. Shaye DA, Tollefson TT, Strong EB. Use of intraoperative computed tomography for maxillofacial reconstructive surgery. JAMA Facial Plast Surg 2015

Management of Post-Traumatic Orbital Zygomaticomaxillary Deformities and Secondary Reconstruction

11

The goals of the craniomaxillofacial trauma surgeon are to primarily achieve proper reduction and adequate internal fixation and avoid any secondary surgery. The restoration of the function and esthetic of the face in secondary surgery can be very challenging and sometimes impossible to achieve. Since the zygomaticomaxillary complex (ZMC) is situated in a critical location, failure to adequately reduce the complex will result in significant secondary functional and esthetic deformities. The post-traumatic ZMC deformity ranges between minimal esthetic deformity and severe functional and esthetic deficits. Post-traumatic ZMC deformity can result from inadequate primary repair or delay in the treatment. Failure to establish the 3D position of the complex is the leading cause of secondary post-traumatic deformity. Each situation requires different planning, but in general, both will need osteotomy to be performed with bone graft to restore the framework and correct the deformity. Patients who suffer from post-traumatic ZMC deformity will have both functional and aesthetic deficits. As it was discussed previously in this book, the ZMC has an intimate contact and relationship with the orbit. Therefore, a non-union or a mal-union of ZMC fracture will result in vertical dystopia, downward slanting of the lateral canthal tendon, enophthalmos, and diplopia (Fig. 11.1a, b).These ophthalmological consequences are usually resolved once the ZMC position is restored to the preinjury location. However, secondary repositioning of the periorbital segment can exacerbate diplopia, and further discussion with the patient should be taken before surgery. So, the goal of the secondary reconstruction of the ZMC is similar to the primary repair. (1) restoration of the facial height, width, and projection and (2) restoration of the orbital volume.

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Fig. 11.1 (a) The 52-year-old male patient who sustained a left ZMC fracture that was improperly reduced. The patient presented with diplopia, enophthalmos, dystopia, downward slanting of the lateral canthal tendon, and flattening of the cheek. (b) Patient tilting his head to the left to compensate for the diplopia

a

b

11.1 Surgical Planning Post-traumatic ZMC defect is caused by delayed treatment or improper primary repair. The minor esthetic deformity can be corrected with camouflage procedures such as filler, fat grafts, onlay bone graft, or cheek implants. The zygomaticomaxillary buttress (ZM) is one of the most common sites of esthetic deformity in secondary reconstruction. Improper primary reduction of the ZM will result in flattening of the face postoperatively. In any post-traumatic ZMC without enophthalmos, onlay bone graft to correct the cosmetic deformity is a viable option. On the other hand, the severe deformity will require osteotomy, bone grafting, and soft tissue suspension. In general, delaying the treatment for more than 3 months will result in malunion of the complex (Fig.  11.2). In these cases, the coronal approach is the preferred surgical approach to get access to all of the articulation of the zygoma and help in mobilizing and fixing the complex in a correctly 3D position. Patients who had their fracture repaired primarily but improperly will have more scarring around the zygoma, and mobilization of the complex will require more releasing of the attachments, including the masseter muscle. Also, the frontal branch of the facial nerve is at a higher risk of injury. A thorough discussion with the patient and counseling should take place prior to any revision surgery. In general, our preferred approach in these cases is the coronal approach for the same reasons mentioned before. In most cases of post-traumatic zygomatic deformity, bone grafting is inevitable, due to the need for osteotomy to mobilize the complex and the loss of the anatomical references secondary to bone healing. Therefore, the coronal access

11.1  Surgical Planning

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Fig. 11.2  Example of severe post-traumatic ZMC deformity secondary to delaying the treatment for 9 months. The patient presented with vertical dystopia, exophthalmos, diplopia, and flattening of the cheek

will provide the surgeon with access to the calvarial bone for grafting simultaneously without the need to create another incision. With the advances in technology, there is a growing interest in patient-specific implants. The polyetheretherketone (PEEK) implants are now more frequently utilized. The PEEK has excellent mechanical properties, is biocompatible, and resists acidity and corrosion. Initially, there were concerns about the increased risk of inflammation in the maxillary sinus with the PEEK implants. However, recent evidence suggested that there is no increase in the risk of infection in the involved paranasal sinuses with the use of PEEK1 (Figs. 11.3 and 11.4). Severe cases of post-traumatic ZMC deformity will require the help of virtual surgical planning and the use of CAD/CAM technology. The detailed technique and the workflow of the use of VSP and CAD/CAM are discussed in another chapter. Here we will summarize the main points. Most of the oral and maxillofacial surgeons are familiar with the use of VSP technology, particularly in orthognathic surgery. However, certain obstacles require careful planning with the post-traumatic ZMC deformities. • Access to the infraorbital rim: The access to this area is minimal, particularly with the transconjunctival approach. Therefore, the cutting guide should be as thin as possible. Bulky guides will never fit and, if forced, can lead to tearing of the lower eyelid. Also, avoid extending the guide toward the medial (Nasal) side of the inferior orbital rim. • The curvature of the inferior orbital rim and lateral orbital wall: These curvatures will prevent the seating of the guide correctly. Therefore, we recommend the guide to be slightly extended into the orbital cavity to help in stabilization. Again, a thin, cutting guide is desired.

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Fig. 11.3  The use of PEEK in the reconstruction of the orbit in left ZMC fracture

Fig. 11.4  The use of PEEK in the reconstruction of the orbit

• If the deformity requires four osteotomy and complete mobilization of the complex, the use of the reduction guide is not very helpful and can be confusing, since there will be no reference to base the reduction of the complex upon. Therefore, in this scenario, we recommend using the 3D stereolithographic model of the reconstruction as a guide to bend the plate. Otherwise, a patient-­ specific implant (PSI) should be fabricated. Notably, the FDA has not approved the midface titanium custom-made plates from all the available commercial companies and has not approved the in-house 3D titanium implants. Most of the post-traumatic ZMC is healed in posterior, inferior, and medial positions. Therefore, when we plan the osteotomy using the VSP, we plan to remove

11.2  Osteotomy and Fixation Technique

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Fig. 11.5  Creating a large step at the inferior orbital rim should be avoided. Here we are showing an example of inappropriate design with a large gap at the inferior orbital rim that will result in a palpable plate and increase risk of exposure

bone from the zygomaticofrontal suture (ZF) and the zygomatic arch. This will help in two folds; first, it will allow positioning the complex in a more superior and anterior position with minimal bone interferences. Second, it will allow for more natural positioning and adaptation of the bone graft and allow for isolation of the bone graft from the saliva intraorally. Also, careful planning during the VSP session to prevent a big step at the infraorbital rim is prudent. This required careful attention because of the thin periorbital skin with increased risk of exposure of the hardware mainly if the periosteum is not closed on top of the plate (Fig. 11.5).

11.2 Osteotomy and Fixation Technique If reconstruction plans to perform ZMC osteotomy in all four articulations of the zygoma, the preferred access should include the coronal incision, transconjunctival incision, and intraoral (vestibular) incision. We start the osteotomy with a reciprocating saw to cut the zygomaticofrontal suture (ZF). A thin osteotome is then used to separate the zygoma down to the zygomaticosphenoid suture (ZS). After that, the arch is osteotomized with a reciprocating saw as planned. Subsequently, attention is made toward the orbital rim and floor. We prefer to osteotomized the floor and the anterior maxillary wall lateral to the infraorbital nerve; this will protect the nerve from injury and provide enough stock of the bone for the reconstruction of the orbital floor (Fig. 11.6). Once mobilization of the complex is achieved, the fixation sequence we tend to follow is similar to the fixation of the acute ZMC fracture. We start the fixation by using a thin curved plate to fixate the ZF. After that, we will establish the AP projection as planned by fixating the arch. Subsequently, the rim is fixated using a thin titanium plate and avoiding any large step. Finally, we fixate the ZM buttress using a thick L-shaped plate. Finally, in severe cases, we utilize the intraoperative navigation and the intraoperative CT imaging to help in confirming the reduction and the reconstruction of the complex as planned.

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11  Management of Post-Traumatic Orbital Zygomaticomaxillary Deformities…

Fig. 11.6  The recom­ mended sequence for osteotomy and fixation

Suggested Reading 1. Suresh V, Anolik R, Power D. The utility of Polyether-Ether-Ketone Implants adjacent to sinus cavities after craniofacial trauma. J Oral Maxillofac Surg. 2018;76(11):2361–9.