Fractures of the Zygomatic Complex and Arch

The zygoma, a major buttress of the facial skeleton, is the principal structure of the lateral midface. A thick strong bone, the zygoma is roughly quadrilateral in shape, with an outer convex (cheek) surface and an inner concave (temporal) surface. The convexity on the outer surface of the zygomatic body forms the point of greatest prominence of the cheek. Therefore, the zygoma plays a major role in facial contour.

The zygoma is roughly the equivalent of a four-sided pyramid (Fig. 16-1). It has temporal, orbital, maxillary, and frontal processes, and articulates with four bones— the frontal, sphenoid, maxillary, and temporal (Fig. 16-2). The body of the zygoma extensively articulates with the maxilla along the anterior maxilla and along the orbital floor (see Fig. 16-2 B ). The suture between these two bones lies just lateral to the infraorbital foramen and runs laterally from the infraorbital rim to the undersurface of the zygomaticomaxillary buttress. It forms the superolateral aspect and part of the superoanterior aspect of the maxillary sinus. The zygoma also has a narrow weak articulation with the zygomatic crest of the greater wing of the sphenoid bone at the lateral aspect of the inferior orbital fissure (Fig. 16-3 A ). It forms a major portion of the lateral aspect and floor of the orbit. The frontal process is thick and triangular in cross section, with facial, orbital, and temporal surfaces. Because of its thickness, it is a frequent site for wire or bone-plate fixation following fracture. The temporal process is flat and projects posteriorly to articulate with the zygomatic process of the temporal bone; the combination of the two makes up the zygomatic arch. The zygomaticotemporal articulation is a thin delicate connection, which fractures frequently and with minimal force.

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B · A · C D

The zygoma provides an origin to a major portion of the masseter muscle along the body and temporal process. In addition, the temporal fascia attaches along the arch and posterolateral edge of the temporal process. The zygoma also provides attachments for the temporal and zygomatic muscles. The strong infraorbital and lateral orbital rims provide protection to the orbital contents.

The malar bone represents a strong bone on fragile supports, and it is for this reason that, though the body of the bone is rarely broken, the four processes—frontal, orbital, maxillary, and zygomatic—are frequent sites of fracture.

H.D. Gillies, T.P. Kilner, and D. Stone, 1927¹

The fracture pattern of any bone depends on several factors, including the direction and magnitude of the force. Fracture lines thus created pass through the areas of greatest weakness of a bone or between bones. Because of the strong buttressing nature of the zygoma and the thin bones surrounding it, most injuries involving the zygoma are accompanied by disruption of adjacent

PART III Management of Head and Neck Injuries articulating bones. This disruption occurs because when a force is applied to the body of the zygoma, it is distributed through its four processes to the adjacent articulating bones, many of which are weaker than the zygoma. Although the zygomatic bone is involved, it is rare to have an isolated fracture of the zygoma in which the fracture lines are completely within this bone or through only the sutures surrounding it.

Zygomatic or malar fractures are the terms commonly used to describe fractures that involve the lateral third of the middle face. Because of the impure nature of zygomatic fractures, other terms have been adopted in describing such fractures. Zygomaticomaxillary complex, zygomaticomaxillary compound,³¹ zygomatico-orbital,²⁶ zygomatic complex,^32,33 malar, trimalar, and tripod fractures are terms that have been used to describe the clinical entity of fractures involving the zygoma and adjacent bones. The latter two terms are misnomers because the zygoma has not three but four processes, and their use should be condemned. Zygomatic, zygomatic complex, or zygomaticomaxillary complex (ZMC) are perhaps the most commonly used. They are used throughout this chapter because the zygoma is the major bone involved in such fractures and for the sake of simplicity. The term zygomatic or ZMC helps distinguish fractures that involve the zygoma and adjacent bones from isolated zygomatic arch fractures, and they are used when this distinction is necessary.

The inferior orbital fissure is the key to remembering the usual lines of ZMC fractures. Three lines of fracture extend from the inferior orbital fissure in an anteromedial, superolateral, and inferior direction (see Fig. 16-3). One fracture extends from the inferior orbital fissure anteromedially along the orbital floor, mostly through the orbital process of the maxilla toward the infraorbital rim. The orbital floor and medial wall are often comminuted, creating multiple lines of fracture within the internal orbit. The infraorbital canal is usually crossed by the fracture line(s) because the fracture frequently extends through the infraorbital rim to the facial surface of the maxilla, above or even slightly medial to the infraorbital foramen. The fracture extends from the infraorbital rim in the maxilla laterally and inferiorly under the zygomatic buttress of the maxilla. Comminution of the infraorbital rim and bone along the anterior and lateral maxilla is common, with frequent involvement of the infraorbital foramen. Therefore, the fracture rarely involves the zygomatic bone along the orbital floor and the anterior and lateral aspects of the face. The fracture lines are mostly within the maxilla.

A second line of fracture from the inferior orbital fissure runs inferiorly through the posterior (infratemporal) aspect of the maxilla and joins the fracture from the anterior aspect of the maxilla, under the zygomaticomaxillary buttress (see Fig. 16-3 C ).

The third line of fracture extends superiorly from the inferior orbital fissure along the lateral orbital wall posterior to the rim, usually separating the zygomaticosphenoid suture (see Fig. 16-3 A and C ). Extending superiorly, laterally, and anteriorly toward the lateral orbital rim, the fracture frequently separates the frontozygomatic suture at the lateral orbital rim. However, the fracture through the lateral orbital rim is occasionally superior or inferior to the frontozygomatic suture.

A ZMC fracture that follows this pattern usually has one additional fracture line through the zygomatic arch. Because the point of least resistance to fracture is not at the zygomaticotemporal suture, but approximately 1.5 cm more posteriorly, the point of fracture when a single fracture exists is usually in the approximate middle of the zygomatic arch, in the zygomatic process of the temporal bone. Frequently, however, three fracture lines exist through the arch, producing two free segments when the fractures are complete (see Fig. 16-3 D ). These segments can be displaced by associated muscle pull or may be pushed medially into the infratemporal fossa. Often, the fractures are incomplete, or greenstick, fractures, producing a medial or lateral warping of the zygomatic arch without notable upward or downward displacement.

This description is for the common or usual ZMC fracture. However, the variability of these fractures is great because of the differences in magnitude and direction of force, amount of soft tissue covering the zygoma, and density of the adjacent bones. Frequently, the lines of fracture are in locations different from those described earlier. Using radiographs to summarize the course of fracture lines in 100 isolated zygomatic injuries, Meyer et al¹¹ have found fractures in the body of the zygoma in almost 40% of cases, compared with the more common medial location along the anterior maxillary surface. Single or multiple lines of fracture (i.e., comminution) may exist. Gross displacement may occur, or no displacement at all. Because of the infinite number of possible variations, one must assess each zygomatic fracture independently and determine the extent and location of the fractures present.

It is probably fair to say that classification of zygomatic fractures according to the individual who tries to describe them. The result has been a confusing array of classification systems that try to describe the anatomic position of the displaced bone or to classify fractures using position and criteria for postreduction stability.^6,22,33-39 Whether a patient receives better treatment from being classified into one system or another is doubtful, and one should not dwell on the many classification systems available. As is true for many other aspects of surgery, it is extremely rare to find two patients who have exactly the same condition.

In 1990, Manson et al⁴⁰ published a classification of midfacial fractures that was based on the amount of energy dissipated by the facial bones secondary to the traumatic force. Their classification of high-, moderate-, or low-energy fractures was based on findings on computed tomography (CT) scans. High-energy fractures had extreme displacement, comminution of the articulations, and segmentation of the bones. They noted that these required extensive exposure and fixation for a satisfactory outcome. On the other hand, lower energy fractures were characterized by displacement but without comminution of bony articulations. They noted that these could be treated by less aggressive means. Using preoperative CT findings may be the most useful way to decide how much intervention may be required before surgery.

It behooves clinicians to evaluate each case individually. Whether they choose to prescribe treatment based on the experience of others for a given class of fracture is their choice; however, with proper surgical management, the nature of the treatment should depend more on the preoperative imaging analysis and surgical findings than on statistical prescription.

In a typical case, diagnosis may be made at sight once the characteristic appearance has been fully recognized. A peculiar facies is present, due chiefly to a certain flatness of contour and an absence of expression on the affected side.

H.D. Gillies, T.P. Kilner, and D. Stone, 1927¹

The diagnosis of zygomatic fractures is primarily based on clinical and radiologic examination, although the history frequently raises a strong suggestion of the possibility that a fracture may exist and gives an indication about the nature, direction, and force of the blow. It should be stressed that the clinical examination is frequently difficult to perform adequately because of the nature of the patient’s mental state and/or the amount of facial edema and pain. The swelling may conceal facial deformity that appears only after the swelling has subsided. If the examination can be performed immediately following the injury and before the onset of edema, more information can be obtained from the clinical examinations. Because there are no sensitive indicators of zygomatic fractures (e.g., those that the teeth provide in maxillary or mandibular fractures), and because the concomitant soft tissue edema and contusion that frequently accompany zygomatic injuries can obscure clinical examination, the use of imaging and clinical findings is important in the diagnosis of ZMC fractures.

CLINICAL EXAMINATION

After the clinician has ascertained the neurologic status of a patient with suspected ZMC fracture, the first priority is determination of the visual status of the involved

eye. A thorough ocular and funduscopic examination should be performed, with complete documentation of the findings. Ocular injuries, such as vitreous hemorrhage, hyphema, globe laceration, severance of the optic nerve, and corneal abrasions, were found in 4% of patients with midfacial trauma by Turvey¹² and in 5% of zygomaticoorbital fractures by Livingston et al.⁴¹ Ophthalmologic consultation was deemed necessary in approximately 5% of 2067 cases of zygomaticoorbital injuries reported by Ellis et al.²⁶ Ioannides et al⁴² found significant ocular and adnexal injuries in 26% of orbital fractures. Al-Qurainy et al⁴³ prospectively performed ophthalmologic examinations in 363 patients who had sustained midfacial fractures. Minor or transient eye injuries, such as corneal abrasion, chemosis, mild impairment of accommodation and visual acuity, and orbital emphysema, were found in 63% of patients. Moderate injuries, such as enophthalmos, conjunctival abrasion, traumatic pupillary changes, iridodialysis, lens damage, macular edema, and moderate to severe impairment of accommodation and visual acuity, were noted in 16% of patients. Severe ophthalmic disorders, such as gross proptosis, retrobulbar hemorrhage, corneal laceration, hyphema, angle recession, severe reduction or loss of vision, visual field loss, choroidal tear involving the macula, and optic nerve injuries, were found in 12% of patients. One third of all patients with comminuted ZMC fractures suffered a severe ocular disorder. Therefore, if the clinician discovers any significant or questionable findings in patients with midfacial fractures, ophthalmologic consultation should be obtained.

Examination of the zygoma involves inspection and palpation. Inspection is performed from the frontal, lateral, superior, and inferior views. One should note symmetry, pupillary levels, presence of orbital edema and subconjunctival ecchymosis, and anterior and lateral projection of the zygomatic bodies. The most useful method for evaluating the position of the body of the zygoma is from the superior view. The patient can be placed in a recumbent position or recline in a chair. The surgeon inspects from a superior position, evaluating how the zygomatic bodies project anteriorly and laterally to the supraorbital rims, comparing one side with the other. The surgeon should lay his or her index finger below the infraorbital margins, along the zygomatic bodies, pressing into the edematous tissue to palpate and reduce the visual effect of edema simultaneously when performing this examination (Fig. 16-4).⁴⁴ The superior view is also helpful for evaluating possible depression of the zygomatic arches. One should not forget to perform an intraoral examination, because zygomatic fractures are often accompanied by ecchymosis in the superior buccal sulcus and maxillary dentoalveolar fractures.

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Palpation should be systematic and thorough, and one side should be compared with the other. The orbital rims are palpated first. The surgeon palpates the infraorbital rims with the index finger, moving the finger rhythmically from side to side along the rim. The lateral orbital rims are palpated with the index finger and thumb. One should also use the index finger along the inner aspect of the lateral orbital rim because fractures may frequently be detected by palpating inside the orbital rim, as opposed to palpating along the lateral aspect. When fractures are present, palpation frequently is accompanied by exquisite tenderness. The body of the zygoma and zygomatic arch are best palpated with two or three fingers in a circular motion, with the surgeon comparing this palpation with that of the opposite side. The zygomatic buttress of the maxilla is palpated intraorally with one finger, and hematoma or irregularities are sought.

Signs and Symptoms

Several signs and symptoms accompany zygomatic fractures. The presence and magnitude of their severity greatly depend on the extent and type of zygomatic injury. For example, facial flattening is more pronounced in injuries in which the zygomatic body has been greatly displaced, as opposed to those in which the body has not been displaced. Similarly, zygomatic arch fractures may be expected to produce less ocular disruption than ZMC fractures. The following signs and symptoms can accompany zygomatic fractures and therefore should be evaluated.

Periorbital Ecchymosis and Edema. Edema and bleeding into the loose connective tissue of the eyelids and periorbital areas is the most common sign following fracture of the orbital rim.^45,46 Swelling, often massive, may be present and is most dramatic in the periorbital tissue, where the eyelids may be swollen closed. The ecchymosis may be in the inferior lid and infraorbital area only or around the entire orbital rim.

Flattening of the Malar Prominence. A characteristic sign and striking feature of zygomatic injury is a flattening of the normal prominence in the malar area. An especially common finding in ZMC injuries, this flattening is reported in 70% to 86% of cases,^22,26,29 especially those in which distraction of the frontozygomatic suture and medial rotation and/or comminution have occurred. If edema is present, flattening may be difficult to discern soon after injury; however, one can usually gain an appreciation of this sign by depressing the index fingers into the soft tissue of the zygomatic areas and comparing one side with the other from above the patient (see Fig. 16-4).

Flattening over the Zygomatic Arch. A characteristic indentation or loss of the normal convex curvature in the temporal area accompanies fractures of the zygomatic arch. Visual and digital comparison with the opposite side is extremely helpful for detection of depressions of the zygomatic arch.

Pain. Severe pain is normally not a feature of zygomatic injuries unless the fractured segment is mobile. Patients do, however, complain of discomfort associated with the attendant bruising. Palpation of the fracture sites also elicits a painful response.

Ecchymosis of the Maxillary Buccal Sulcus. An important sign of zygomatic or maxillary fracture is ecchymosis in the maxillary buccal sulcus. Ecchymosis may occur even with a small disruption of the anterior or lateral maxilla and should be sought in patients with suspected zygomatic fractures.

Deformity at the Zygomatic Buttress of the Maxilla. Intraoral palpation of the anterior and lateral aspects of the maxilla frequently reveals irregularities of the normally smooth contour, especially in the area of the zygomatic buttress of the maxilla. Crepitation from comminuted fragments of bone is also frequently palpable. If no tenderness is experienced during this maneuver, the chances are that no fracture exists. The absence of pain makes a zygomatic fracture unlikely, but its presence does not establish one because the pain can be a result of soft tissue injury and/or maxillary fracture.

Deformity of the Orbital Margin. Fractures running through the orbital rim often result in a gap, or step deformity, if displacement has occurred. This finding is frequently noted at the infraorbital and lateral orbital rims when zygomatic fractures are present.^45,46 These areas may also be tender to touch.

Trismus. Limitation of mouth opening frequently accompanies zygomatic injuries and is present in approximately one third of cases.^26,46,47 This condition occurs with an even higher incidence in isolated fractures of the zygomatic arch (45%). The reason often cited for postfracture trismus is impingement of the translating coronoid process of the mandible on the displaced zygomatic fragments. Whether this contact actually occurs in most cases is doubtful, because the amount of displacement necessary for producing actual mechanical interference is great. A more likely explanation is muscle spasm secondary to impingement by the displaced fragments, especially on the temporal muscle (Fig. 16-5). An associated finding is deviation of the mandible toward the fractured side when the mouth is opened.

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Abnormal Nerve Sensibility. An important symptom, present in approximately 50% to 90% of ZMC injuries, is impaired sensation of the infraorbital nerve.^22,26,45-52 Infraorbital nerve paresthesia is more common in fractures that are displaced than those that are not. It is difficult to differentiate true anesthesia from the altered sensation of swollen edematous tissue but, as the swelling decreases, infraorbital nerve anesthesia becomes apparent. Infraorbital anesthesia occurs when the fracture through the orbital floor and/or the anterior maxilla causes tearing, shearing, or compression of the infraorbital nerve along its canal or foramen (Fig. 16-6). Frequently, the entire orbital floor is comminuted, which results in multiple fragments of bone strung together by the infraorbital neurovascular bundle. When the line of fracture is lateral to the infraorbital groove and foramen (less common), the infraorbital nerve is spared. Disruption of the infraorbital nerve causes anesthesia of the lower eyelid, upper lip, and lateral aspect of the nose.

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A related symptom may be altered sensitivity of the maxillary teeth and gingiva.⁵³ When this altered sensitivity is present, the clinician should suspect a disruption of the infraorbital nerve within its canal, where the middle and anterior superior alveolar nerves take origin.

Epistaxis. Whenever the sinus mucosa is disrupted, hemorrhage into the sinus is possible. Most fractures through the sinus wall that have had even a minor amount of displacement tear the lining mucosa, producing internal bleeding. Because the maxillary sinus drains into the nose via the middle meatus, unilateral hemorrhage from the nose is possible and occurs in approximately 30% to 50% of ZMC injuries.^26,46

Subconjunctival Ecchymoses. Subconjunctival hemorrhage, a frequent finding in zygomatic fractures, is present in 50% to 70% of cases.^26,46 It may accompany even a hairline crack through the orbital rim if the periosteum has been torn. Its absence does not exclude an orbital rim fracture because if no disruption of the periosteum has occurred, bleeding can accumulate in a subperiosteal location and may not be visible under the conjunctiva. When present, subconjunctival ecchymoses usually have no posterior limit and will be bright red because of the ability of oxygen to diffuse through the conjunctiva to the collection of blood.

Crepitation from Air Emphysema. Fracture through a sinus wall with tearing of the lining mucosa allows air to escape into the facial soft tissue if the pressure within the sinus is greater than that within the tissue. The soft tissue of the periorbital area, especially the eyelids, is prone to inflation with air because of its loose areolar nature. When inflation occurs, one can palpate crepitation, indicating subcutaneous emphysema. Crepitation is most easily appreciated by alternatively rolling two fingers gently over the tissue, which produces a characteristic crackling sensation. It is an uncommon finding following zygomatic fractures, but the potential for air emphysema is constant. When present, however, crepitation can be alarming to the patient. The emphysema disappears spontaneously in 2 to 4 days without treatment. The significance of emphysema is the potential for infection through the communication between the sinus and the soft tissue.

Displacement of the Palpebral Fissure. The lateral palpebral ligament is attached to the zygomatic portion of the orbital rim. Displacement of the zygoma carries the palpebral attachment with it and thus produces a dramatic visual deformity. When the zygoma is displaced in an inferior direction, the lateral palpebral ligament is also depressed, causing a downward slope to the fissure (antimongoloid slant) (Fig. 16-7). Because the orbital septum is attached to the infraorbital rim, inferior or posterior displacement of the inferior orbital rim causes depression of the lower eyelid, giving it a shortened appearance.⁵⁴ This depression may cause more sclera to be exposed below the iris and an apparent ectropion.

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Unequal Pupillary Levels. With the disruption of the orbital floor and lateral aspect of the orbit that frequently accompanies zygomatic fractures, loss of osseous support for the orbital contents and displacement of Tenon’s capsule and the suspensory ligaments of the globe permit depression of the globe.⁵⁵ This displacement is manifested clinically as unequal pupillary levels, with the involved pupil at a level lower than that of the normal side (see Fig. 16-7).

Diplopia. Diplopia is the name given to the symptom of blurred vision. Two varieties of diplopia exist; it is important to distinguish between them. Monocular diplopia, or blurring of vision through one eye with the other closed, requires the immediate attention of an ophthalmologist, because it usually indicates a detached lens, hyphema, or other traumatic injury to the globe. Binocular diplopia, in which the blurring of vision occurs only when the patient looks through both eyes simultaneously, is common and occurs in approximately 10% to 40% of zygomatic injuries.* Al-Qurainy et al⁶⁵ have found that the severity of diplopia is associated with the severity of midfacial injuries. Almost 30% of patients with comminuted fractures of the ZMC experienced diplopia, 22% of patients with noncomminuted displaced ZMC fractures had diplopia, and only 8% of patients with minimally displaced or nondisplaced ZMC fractures had diplopia. Binocular diplopia that develops following trauma can be the result of soft tissue (muscle or periorbital) entrapment, neuromuscular injury, intraorbital or intramuscular hematoma or edema, or a change in orbital shape, with displacement of the globe causing a muscle imbalance. Enophthalmos and globe ptosis associated with marked displacement of the globe can also cause diplopia.

A useful point in differentiating the cause of diplopia is the finding that general edema of the orbit usually causes diplopia in the extremes of upward and downward gaze. Almost complete lack of eye movement in one direction is present with mechanical interference or neuromuscular injury, most commonly muscle entrapment. The diagnosis of diplopia can be difficult in the early stages of an injury, when severe edema of the orbit and eyelids is present. Diplopia of edema or hemorrhagic origin should resolve in a few days, whereas diplopia caused by entrapment of orbital tissue does not.

One can determine the presence of entrapment of orbital contents by the fracture through the orbital floor with a forced duction test. Small forceps are used to grasp the tendon of the inferior rectus through the conjunctiva of the inferior fornix and the globe is manipulated through its entire range of motion (Fig. 16-8). Inability to rotate the globe superiorly signifies entrapment of the

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*References 15, 22, 26, 34, 35, 46, and 56-64.

between entrapment of orbital contents and paralysis as a result of neuromuscular injury or edema. The test should be performed routinely in those who cannot rotate the globe into an upward gaze.

Enophthalmos. If the zygomatic injury has produced an increase in orbital volume, usually by lateral and inferior displacement of the zygoma and/or disruption of the inferior, medial, and/or lateral orbital walls, or has resulted in a decrease in orbital soft tissue volume by herniation of orbital soft tissue, enophthalmos can result. This diagnosis is difficult to make acutely unless the enophthalmos is severe because adjacent soft tissue edema always produces a relative enophthalmos. After the swelling has dissipated, enophthalmos becomes more obvious and is frequently associated with ptosis of the globe. The clinical manifestations of enophthalmos are accentuation of the sulcus of the upper lid and narrowing of the palpebral fissure, causing pseudoptosis of the upper lid. The anterior projection of the globe as viewed from above is reduced on the side of injury. Zygomatic fractures are associated with enophthalmos in approximately 5% of cases before treatment.^22,26,46 If enophthalmos is present during the initial examination, it is likely that a great increase in bony orbital volume has occurred.^66,67

RADIOLOGIC EVALUATION

Nothing is more valuable to the surgeon in determining the extent of injury and the position of the fragments—both before and after operation—than a good skiagram.

H.D. Gillies, T.P. Kilner, and D. Stone, 1927¹

By 1992, CT essentially supplanted other radiologic methods in the assessment of patients with midfacial injuries.⁶⁸ Two-dimensional CT is now considered the best and most useful means of radiologic assessment of the injured facial skeleton.⁶⁹ The amount of information that can be obtained with CT is much greater than that which can be obtained from a series of plain films. CT accurately identifies lines of fracture, position and displacement of the ZMC, and status of the zygomatic arch (Fig. 16-9). CT scans are especially helpful in that they allow a complete assessment of the status of the orbital floor and walls and the depth to which one must dissect to reach stable bone. CT has eliminated the question about whether the orbit should be explored. With the accurate image of the internal orbit provided by CT, one can make a decision regarding the necessity for internal orbital reconstruction before surgery.

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The status of the orbital soft tissue can also be assessed because of the great contrast provided by CT. Comparison of globe projection from one side with the other helps identify enophthalmos in unilateral injuries.^66,67,70,71 Also, CT scans allow identification of associated craniofacial injuries.⁷² For ZMC injuries, it is optimal to obtain axial and coronal high-resolution scans. The axial scan is extremely helpful in evaluating the medial and lateral orbital walls, and the coronal scan defines the extent of injury to the orbital floor (see Fig. 16-9). Reformatted coronal views (from axial scans) are not as helpful but may be necessary if the patient cannot be properly positioned because of injury. Three-dimensional CT scans offer no additional information beyond what is already present in twodimensional scans but are useful to understand the displacement and fracture patterns.^73,74

The methods of treating a fractured malar bone recommended by the various writers who have reported

cases include simple digital manipulation under general anesthesia, external manipulation by means of a cowhorn dental forceps grasping the edges of the bone, traction and elevation by means of wire or heavy bone elevators passed through small local external incisions, and elevation via incision in the mucosa of the gingival sulcus at the canine fossa.

Our technique, which has now been used successfully in a number of cases, differs from those mentioned. H.D. Gillies, T.P. Kilner, and D. Stone, 1927¹

Since Duverney⁷⁵ first described the fractured zygoma, numerous methods have been suggested for treating it. These range from nonintervention and observation to open reduction and internal fixation (ORIF). Because many fractures are nondisplaced or minimally displaced, intervention is not always necessary. Studies have shown that between 9% and 50% of ZMC fractures do not require operative treatment (Table 16-1).

The decision to intervene should be based on signs, symptoms, and functional impairment. The decision need not be made hastily because ZMC fractures are not emergencies and treatment can be delayed, if necessary. However, during the first week following trauma, the soft tissue undergoes changes consistent with the usual sequence of wound healing. The form that they will ultimately take depends on the underlying bony architecture. If a comminuted ZMC is not treated for several days following injury, an excellent reduction may be compromised by the soft tissue scarring and change in morphology that occur between the time of injury and fracture repair. Optimally, fractures are treated before the onset of edema from the traumatic incident. In practice, however, such timing of treatment is rarely possible. When edema is moderate to severe, postponement of surgery for several days makes thorough examination and surgical treatment reliable and much easier tasks. Therefore, postponement of the decision to operate until facial edema resolves is recommended when the necessity for intervention is questionable. This approach may be used in fractures that are minimally displaced, when radiographic examination of the internal orbit shows no major defects. However, if the radiographic findings are so dramatic that intervention is definitely necessary, it may be advantageous to perform the surgery regardless of the facial edema present, because the final soft tissue contour may be superior to that which may occur when surgery is postponed. If the surgeon decides not to intervene, the patient should be observed for 2 to 3 weeks and a soft diet should be prescribed.

One should always remember that if a force is sufficient to produce a fracture of the zygoma, it is also sufficient to produce intracranial injuries. ZMC fractures are not life-threatening injuries and should not be given priority over more acute problems. Treatment need not be hastened if the neurologic state of the patient is in question because zygomatic fractures can be satisfactorily treated in several days, after the facial edema has resolved.

Another important consideration in deciding whether to intervene is the status of the opposite eye. If the patient has diminished vision in the eye on the side opposite the fracture for any reason, one may decide not to treat the displaced ZMC fracture associated with the only normally functioning eye. Although the risk to vision is minimal when ZMC fractures are treated, loss of sight in the only functioning eye would be a catastrophe. Therefore, the patient must be educated so that an informed decision can be made.

If intervention is deemed necessary, proper treatment, as for any displaced fracture, requires reduction and, if necessary, fixation. Because closed reduction using external manipulation is impossible, all reduction techniques are operative procedures (i.e., open) in the sense that the skin or mucosal surfaces are violated.

One must be aware that ZMC fractures can result from high- and low-energy injuries.⁴⁰ Those resulting from altercations seem to be more linear in character and displaced en bloc (Fig. 16-10). These fractures can frequently be treated with limited exposure, simple reduction, and simple methods of fixation, if necessary. Conversely, high-energy injuries, such as those sustained in MVAs, produce more comminution, especially of the adjacent bones, where the ZMC abuts, and are much less amenable to simple methods of treatment (Fig. 16-11). These fractures usually require extended open reduction and rigid fixation techniques. The surgeon must therefore be aware of the nature and extent of the injury as treatment is planned.

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Many methods are available for the reduction and fixation of zygomatic fractures, which indicates that no one technique is always superior to the others. Few if any procedures are always satisfactory for every type of zygomatic fracture, so the surgeon’s judgment and ability to apply a satisfactory modality to a given fracture are the deciding factors in whether the patient receives appropriate treatment. It should be stressed that satisfactory results can be achieved using a number of techniques. It is not so much the actual technique, but the proper application of principles, that produces satisfactory results.

The fractured zygoma is perhaps the least understood and most frequently mistreated facial fracture. Much of the difficulty in treating these fractures stems from the complex and multiple anatomic relationships that the zygoma maintains within the facial skeleton. The most common mistake made in clinical practice is to assume that the ZMC will be in its proper position if the infraorbital and lateral orbital rims have been reduced. One must remember that the fractured ZMC has four major processes that articulate with adjacent bones. Only when three are properly positioned can one be sure of an accurate reduction. It may be more helpful to think of the zygoma as a four-legged chair. If three of the four legs are on the floor, the other must also be on the floor. On the other hand, if two legs are on the floor, two may also be off the floor. Therefore, reducing orbital rim fractures (two legs of the chair) does not guarantee that the entire complex has been properly reduced, because the zygoma can rotate inferiorly and medially (Fig. 16-12). In this case, fractures through the zygomatic buttress of the maxilla and zygomatic arch are left improperly aligned,⁸⁰ producing a flattened appearance to the face in the area in which the body of the zygoma normally gives soft tissue support.

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Axis of · Rotation · ZMC · Displacement

Because of the ZMC’s difficult anatomic details, and because there are no sensitive clues to accurate and stable reduction, some surgeons have suggested that each ZMC fracture be treated aggressively, with ORIF of at least two of its four major processes.^17,81-85 Dingman and Natvig,⁸¹ for example, have stated that “While closed reduction techniques are popular and attractive in the management of fractures in this region, the experienced surgeon will be quick to see, in many cases, the limitations that closed methods impose.” The main controversies in the treatment of ZMC fractures are the following:

1. Should surgical exposure of the zygoma in two or three locations routinely be performed to determine whether the reduction has been adequate?

2. Should fixation devices be routinely applied?

3. Does the internal orbit require reconstruction? It is noteworthy that the most common treatment

errors that lead to poor results also center on these same topics.

DETERMINING WHETHER THE ZYGOMA HAS BEEN PROPERLY REDUCED

There should be no doubt that observation of the fracture in three of its four processes will allow the surgeon to determine the postreduction position accurately. Karlan and Cassisi⁸⁰ have shown this to be true in a clinical review of their patients. The question therefore becomes whether this is always necessary. Recommendations in the literature for reduction of ZMC fractures range from closed reduction techniques^78-79 to three- or four-point surgical exposure.^89-92 Incisions used to expose the lateral orbital, infraorbital, and zygomaticomaxillary buttress (intraorally) areas not only take time but also have the potential to produce complications of their own, regardless of the zygomatic fracture for which they are being used (see later, “Complications”).

In several cases, however, surgical exposure becomes helpful. First, when preoperative signs and symptoms and/or radiographs indicate the need for internal orbital reconstruction, it is prudent to gain access to the infraorbital rim and orbital floor before elevation of the zygoma. Second, if surgery must be performed while excessive facial edema is present, surgical exposure to determine the position of the ZMC is helpful. Third, if one cannot determine whether the reduction has been adequate during the surgery, exposure will provide the necessary verification. Fourth, surgical exposure is helpful if fixation devices are deemed necessary from the preoperative assessment of the fracture. Thus, the use of surgical exposure depends on the circumstances and experience of the surgeon; however, given these examples, it will be frequently performed. If there is any doubt about the postreduction ZMC position, one should verify it with exposure, remembering that even though the orbital rims are reduced, the body of the zygoma can be rotated medially. Exposure and exploration of other areas help determine when the zygoma has been properly reduced. Fractures at the zygomatic arch and internal orbit along the greater wing of the sphenoid (Fig. 16-13 A ) are sensitive indicators of ZMC position.

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PART III Management of Head and Neck Injuries

However, exposure of the zygomaticomaxillary buttress (intraorally; see Fig. 16-13 B ) provides one of the most valuable clues about the adequacy of ZMC position, if it is not severely comminuted. With this exposure, one will also have excellent exposure of the infraorbital rim. It should be realized that a reciprocal relationship exists between malar projection and facial width. If the zygomatic arch is bowed laterally, the malar eminence is posteriorly displaced (Fig. 16-14). Reduction of ZMC fractures should ensure that the malar eminence is properly projected anteriorly and, if the zygomatic arch is reconstructed, the procedure is done by keeping it flat.

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If the surgeon has navigation and/or intraoperative CT scanning available, the amount of surgical intervention can often be minimized. Either of these tools can assess the position of the ZMC and internal orbital floor reconstructions in the operating room. Thus, one can often use a more limited exposure, reduce the fracture, and determine whether the ZMC is in proper position.

Another important point that should be stressed in the treatment of ZMC fractures is the status of the medial orbital rim. Occasionally, a unilateral nasal-orbitalethmoid fracture occurs on the side of the ZMC fracture, displacing the medial portion of the infraorbital rim laterally. This portion of bone may seem to be very stable and the fact that it is malpositioned may go unnoticed. If the ZMC is reduced into apposition with this laterally displaced fragment of infraorbital rim, the ZMC will be laterally positioned, increasing orbital volume and widening the face (Fig. 16-15). Because a unilateral nasalorbital-ethmoid fracture may be difficult to diagnose clinically, preoperative CT scans are the best diagnostic tool (see Fig. 16-9 A ). Therefore, one should always search for fractures of the medial orbital rims when assessing preoperative scans.

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NEED FOR FIXATION

One of the most controversial topics in maxillofacial surgery is the amount of fixation necessary to prevent postreduction displacement of the fractured ZMC.^93-95 Some have noted that reduction, by itself, does not produce adequate stability of the fractured zygoma, claiming that the downward pull of the masseter muscle will cause a medial rotation of the zygomatic body before healing.* Albright and McFarland⁹⁶ went so far as to recommend intermaxillary immobilization following fracture reduction to help reduce the pull of the masseter muscle on the repositioned ZMC. The masseter muscle has often been implicated as a primary cause of postreduction displacement of the fractured ZMC. It was assumed to be capable of exerting sufficient inferiorly directed force on the fractured ZMC to cause movement, even after surgical insertion of fixation devices. However, this contention has never been proven. There is no evidence in the literature that postreduction displacement of a ZMC fracture has occurred in patients. Previous clinical studies simply evaluated patients clinically and radiographically months after surgery and noted an occasional patient with poor ZMC position. It was assumed that because the fractures were simply elevated, or perhaps stabilized with wire fixation, postsurgical displacement had occurred. Therefore, recommendations for fixation have varied from none to the placement of three or four bone plates at different locations around the fractured ZMC.

Ellis and Kittidumkerng⁹⁹ have reviewed a series of isolated ZMC fractures treated by different approaches and fixation schemes, both immediately and several weeks after repair, and found no evidence of postreduction

*References 9, 80, 81, 84, and 96-98.

instability in any patient. Based on their experience and the data generated from their study, various methods can be used successfully to stabilize ZMC fractures. These range from reduction without fixation to reduction with three- or four-point fixation using bone plates.

Such a diversity of treatment options should not be surprising, given the results of a study by Dal Santo et al.⁹⁵

Thier study compared masseter muscle force in 10 male control subjects with that in 10 male patients who had sustained unilateral ZMC fractures. The calculation of muscle force was based on measured bite force, electromyograms, and radiographic determination of muscle vectors. It was found that the masseter muscle developed notably less force in patients with ZMC fractures than in

control subjects. Following fracture, masseter muscle force slowly increased, but at 4 weeks after surgery, most patients were still well below control levels. The results of that study cast doubt on the role of the masseter muscle in postreduction displacement of the fractured ZMC and indicate that potentially minimum amounts of fixation are required for such injuries.

Most have disagreed with the concept that fixation should be routinely applied following reduction of zygomatic fractures.* These surgeons applied fixation to zygomatic fractures only where indicated. The indications for the application of fixation seem to vary with the surgeon and type of fracture, so the incidence of fixation application varies widely in the literature (8% to 100%) (Table 16-2).

The efficacy of using simple elevation (without fixation) when indicated has been demonstrated by Larsen and Thomsen.²² They reexamined 87 patients several months to years after elevation of their fractures by the Gillies temporal approach and found only 2 patients with residual deformity. Similarly, Fischer-Brandies and Dielert²⁵ reexamined 41 cases of zygomatic fracture treated with elevation using a hook and found no postsurgical displacement. Several other studies in the literature have used ZMC repositioning without fixation, with good results,^29,78-79 verifying that fixation requirements are less than advocated by some. Fixation with one bone plate has been advocated by several surgeons in a certain percentage of ZMC fractures, either at the zygomaticomaxillary

*Only those cases that were surgically treated in these studies are included in this table.

buttress* or, more commonly, at the frontozygomatic area.^† Champy et al¹¹¹ used a single bone plate at the frontozygomatic area in 342 isolated ZMC fractures and found that only 6 (1.8%) had an unsatisfactory result. Tarabichi¹⁰⁰ treated 17 consecutive low-velocity ZMC fractures by a transoral open reduction and internal bone-plate fixation of the zygomaticomaxillary buttress, with excellent results in all but 2 patients, who had comminution of the orbital rim. Covington et al⁷⁹ were able to stabilize 30% to 40% of ZMC fractures by one-point fixation. Ellis and Kittidumkerng⁹⁹ were able to use one-point fixation in 31% of ZMC fractures reported in their study. Similar results were shown by Shumrick et al.¹¹⁴

An important point regarding the stability of ZMC fracture reduction is the state of the fracture ends. Where the osseous processes are not comminuted, the fracture is more likely to remain stable without fixation devices.

*References 95, 99, 100, 112 and 113. †References 52, 88, 79, 89, 108, 109.

*References 8, 13, 15, 22-29, 33, 61, 78, 88, 79, 95, and 99-111.

However, when comminution of the fragments has occurred, instability usually results and fixation devices become necessary. Thus, comminuted fractures behave differently from linear fractures. If there is any question about the stability of a reduced zygomatic fracture, it is prudent to apply fixation.

NEED FOR INTERNAL ORBITAL RECONSTRUCTION

By definition, the orbital floor is fractured in ZMC fractures. However, the magnitude and extent of orbital floor disruption vary from a linear crack to fragmentation of the entire floor and medial and lateral walls. Many, perhaps most, low-energy ZMC fractures do not have herniation of periorbital contents into the sinus with entrapment of ocular muscles or enophthalmos. However, these problems do occur in a certain percentage of cases. Davies¹¹⁵ noted significant orbital floor disruption in 47% of patients with zygomatic fractures. Sacks and Friedland¹¹⁶ noted this complication in two thirds of ZMC fractures. Crewe¹¹⁷ noted notable disruption in most zygomatic fractures. Crumley and Leibsohn⁶⁴ noted that 39% of zygomatic fractures had comminuted fractures of the orbital floor. The need for orbital floor reconstruction to support the periorbital tissue was necessary in two of three cases of orbital floor exploration performed by Pozatek et al⁷⁶ and Wiesenbaugh.⁴⁶ Ellis et al²⁶ found it necessary to place implants in one of three cases on exploration of the orbital floor. The orbital floor and walls were reconstructed in 44% of isolated ZMC fractures in a study by Ellis and Kittidumkerng.⁹⁹ A similar study by Shumrick et al found the necessity to reconstruct the internal orbit in only 30% of ZMC fractures.¹¹⁴

Although some surgeons believe that so-called exploration of the internal orbit should be performed routinely when operating on ZMC fractures,* most do not. These surgeons would argue that exploration of the orbit should depend on preoperative and intraoperative findings. Fortunately, CT scans have eliminated the debate about when an orbit should be explored. It is now possible to obtain an accurate assessment of the status of the internal orbit before surgery so that adequate treatment can be proscribed and planned.^114,118 If comminution of the orbital floor and walls and/or prolapse of orbital soft tissue into the maxillary and ethmoid sinuses is noted, or if orbital volume has increased from blowout of the floor and walls, reconstruction should be performed.^119,120 Using similar criteria in the preoperative CT scans, Reddy and Ellis were able to classify patients successfully into those who required and those who did not require internal orbital reconstruction.¹¹⁸ They showed that in those who were determined not to need internal orbital reconstruction, good radiographic and clinical results were obtained.

With the availability of intraoperative CT scanning in some operating rooms, the question about whether to reconstruct the internal orbit in those patients in whom the preoperative CT scan does not show gross disruption can be answered in the operating room. After the ZMC has been reduced, a scan is taken and an assessment of the internal orbit is made. The surgeon can then decide whether it is necessary to reconstruct the orbital walls (Fig. 16-16).

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PRINCIPLES IN THE TREATMENT OF ZYGOMATICOMAXILLARY COMPLEX FRACTURES

In the treatment of any ZMC fracture that requires surgical intervention, consideration should be given to each of several steps in a sequential and orderly manner (Box 16-1).

Prophylactic Antibiotics. The incidence of infection following ZMC fracture or fracture reduction is extremely low; however, such an infection is difficult to discern because many surgeons routinely use prophylactic antibiotics. This practice also makes it difficult to determine the effectiveness of antibiotics in preventing infection of these fractures. Because the maxillary sinus is involved, ZMC fractures can be considered compound, and prophylactic antibiotics are probably appropriate, especially given the fact that the orbital contents are also frequently violated. The choice of antibiotics should cover routine sinus bacteria (e.g., ampicillin, amoxicillin, clindamycin, cephalosporin).

Anesthesia. For isolated ZMC fractures, general anesthesia with oral intubation is helpful. The anesthesiologist or anesthetist should be positioned so that the surgeon has access to the side of the fracture and head of the table. It is very important to have complete access to the top of the patient’s head for visual comparison of one side with the other. (Reduction of isolated zygomatic arch fractures can be performed with the patient under local anesthetic, with or without sedation when the patient is cooperative, and an intraoral or a percutaneous approach is used.)

Clinical Examination and Forced Duction Test. Following induction of general anesthesia, the surgeon should take the opportunity to examine the patient more carefully. With the patient under anesthesia, the surgeon has more freedom in the examination and can use more digital force than is possible with the patient awake. This examination can help confirm previous diagnoses and may reveal new information. It is very important to look at the patient from the superior view and to visualize both zygomas simultaneously. Unless the swelling is marked, one should be able to determine an asymmetry. Laying the index finger across the infraorbital area or on the malar prominence should help discern the asymmetry (see Fig. 16-4). A forced duction test should also be performed at this time (see Fig. 16-8).

Protection of the Globe. The cornea must be protected from inadvertent trauma. Of the several ways of providing this protection, perhaps the simplest is placement of a scleral shell (corneal shield) after application of an ophthalmic ointment (Fig. 16-17 A ). Temporary tarsorrhaphy can also be used by suturing the dermal surfaces of the upper and lower eyelids together with 5-0 nylon sutures (see Fig. 16-17 B and C ).

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Antiseptic Preparation. The type of preparation necessary depends largely on the type of approach(es) that are anticipated. It is good practice, however, to prepare the forehead, both periorbital areas and cheeks to the level

*References 17, 85, 92, 102-111, 113, 113a, 112.

continued

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F · E · G · H

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continued

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N · M · 10.00mm/div · O · 10.00mm/div · 10.00mm/div · P · 10.00mm/div

PART III Management of Head and Neck Injuries of the mouth, and both sides of the preauricular area. Such preparation allows comparison of the affected side with the opposite side during surgery. Another useful suggestion is always to prepare the mouth with throat pack and antiseptic rinse, because an oral approach to the sinus and/or zygoma is frequently useful. If the preoperative clinical and radiographic examinations suggest that a coronal approach may be necessary, the hair and ears are prepared and draped.

Reduction of the Fracture. The fracture should be reduced by whatever means the surgeon deems appropriate (techniques described later).

6. Reduction of the fracture

Assessment of Reduction. The most important step in the management of ZMC fractures is to determine at the table whether the fracture has been properly reduced. The success or failure of reduction will be obvious for those who have opened the fracture at three sites. If exposure at three sites has not been performed, the orbital margins are the areas that should be palpated first

7. Assessment of reduction

BOX 16-1 Steps in Surgically Treating a Zygomaticomaxillary Complex Fracture

1. Prophylactic antibiotics

2. Anesthesia

3. Clinical examination and forced duction test

4. Protection of the globe

5. Antiseptic preparation

10. Internal orbital reconstruction

11. Assessment of ocular motility

12. Bone graft extraorbital osseous defects

13. Soft tissue resuspension

14. Postsurgical ocular examinations

15. Postsurgical images

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to determine reduction. If reduction has been satisfactory, these margins will be smooth and continuous. This finding by itself, however, is inadequate verification that the zygoma is properly positioned. Although the zygomaticofrontal suture area provides the strongest pillar of the zygoma, it is one of the worst indicators of proper reduction of the entire complex, even when surgically exposed and evaluated directly. One should also palpate in the maxillary vestibule. If there is any flatness still visible, the zygoma has not been properly elevated. If there is any doubt about proper reduction, exposure is mandatory. In this case, an incision in the maxillary vestibule offers excellent exposure of the zygomaticomaxillary buttress and the infraorbital rim.

For surgeons who have navigation or intraoperative CT scanning available, assessment of the reduction is relatively easy.Determination of the Necessity for Fixation. The second most important step in surgically treating zygomatic fractures (following determination of whether the reduction has been satisfactory) is determining whether the reduction will be stable by itself or needs some form of fixation. If constant reduction force is necessary for maintaining ZMC position, the ZMC should be stabilized with some form of fixation device(s). If the zygomatic position is deemed appropriate and does not require constant application of reduction force, one should press with moderate pressure on the malar eminence with the fingers and see whether displacement results. If it does not, fixation devices may be unnecessary. Many minimally displaced cases are stable after they have been reduced. However, if there is any doubt about postreduction stability, the application of fixation devices is prudent.

Application of a Fixation Device. The methods of stabilizing the fractured ZMC vary with the imagination and experience of the surgeon. General principles are involved, however (see later).

Internal Orbital Reconstruction. When indicated, reconstruction should be carried out after repositioning and stabilizing the ZMC fracture. In such cases, the orbital floor and walls should be exposed before elevation of the

ZMC so that the open orbital rim can also serve as a guide to reduction. However, it is unwise at this point to try to free any trapped tissue, because elevation of the zygoma may separate bone fragments and make this maneuver much easier following reduction. Assessment of the magnitude of the defect to be reconstructed is made following reduction, because the actual defect will then be revealed (techniques described later).

In minimally displaced cases in which no ocular signs of entrapment or enophthalmos are noted preoperatively, and in which the fracture is treated by simple reduction, internal orbital exploration and/or reconstruction is unnecessary unless a postreduction forced duction test produces positive findings (rare). In most of these cases, reduction of the zygoma results in adequate alignment of the orbital floor.^33,114,118 However, one should never avoid reconstructing the internal orbit for fear of causing harm to orbital tissue. This occurrence is extremely rare. For those surgeons who have intraoperative CT scanning capability, the status of the internal orbit after reduction of the ZMC is known and the decision about the need for internal orbital reconstruction can be made during the surgery.

Assessment of Ocular Motility. Another forced duction test should be performed at the end of all active treatment, with the possible exception of suturing, to verify that the treatment did not create entrapment of orbital contents (see Fig. 16-8).

Bone Graft for Extraorbital Osseous Defects. Consideration should be given to grafting areas of missing bone along the anterior maxilla and zygomaticomaxillary buttress. Even though bone plate fixation may provide stabilization of the ZMC by spanning such defects, it is unclear how long bone plates will provide such stability. Reconstruction of the skeleton with bone grafts prevents soft tissue prolapse from the cheek into the maxillary sinus and promotes osseous union across the defect, providing long-term stability (Fig. 16-18).

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Soft Tissue Resuspension. In 1991, Phillips et al¹²¹ described a method of soft tissue suspension of infraorbital and malar soft tissues before closing incisions after treating midfacial fractures. They hypothesized that these soft tissues droop if not resuspended; the drooping results in facial asymmetry and provides traction on the lower eyelid, causing ectropion. Yaremchuk and Kim¹²² have confirmed this hypothesis and found a 20% incidence of scleral show when the facial soft tissue was not resuspended but no scleral show when the tissue was resuspended. Thus, for fractures in which the soft tissue was completely stripped from the bone, sutures should be passed through the deep surface of the soft tissue of the cheek and secured to structures such as the orbital rim and temporal fascia to raise them into their proper location on the underlying bone (Fig. 16-19; see also Fig. 16-25 F ).

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384 PART III Management of Head and Neck Injuries · Skin · Subcutaneous CT · Galea aponeurosis · Subapon. areolar tissue Scalp · Periosteum · Skull · Ant. auricular m. · Skin incision · Temporalis m.; temporal fascia · Incision through outer layer of temp. fascia · temporal br. of VII · Inner layer of temp. fascia · Zygomatic arch · Zygomatic br. VII · Parotid gland · Masseter m. · Ramus of mandible · B · A · Temporal Temporal fascia (TF) · Outer · inner · Fatty tissue · Zygomatic Zygomatic arch · arch Skin flap · Outer layer of TF · Periosteum · D · C · Temporalis m. · Zygomatic · arch F · E

Postsurgical Ocular Examination. The pupillary reflexes should be monitored postoperatively and the fundus examined periodically. Visual acuity must also be checked. Because of surgical edema, binocular diplopia will probably be present, depending on the surgical procedure.

Postsurgical Images. Postoperative images should be obtained whenever the patient is stable. Axial and coronal CT scans are recommended to assess adequacy of reduction and internal orbital reconstruction, if performed.

SURGICAL APPROACHES TO ZYGOMATICOMAXILLARY COMPLEX FRACTURES

Many techniques have been advocated for reducing and stabilizing ZMC fractures. These approaches will be described after a discussion of the surgical approaches used to gain access to the ZMC. Techniques of orbital exploration and reconstruction will then be presented.

A standard series of approaches has been used extensively for approaching the fractured ZMC and orbit. Existing lacerations are often used for this purpose. In the absence of lacerations, properly placed incisions offer excellent access, with minimal morbidity and scarring.

Protection of the cornea during operative procedures is mandatory in all operations in the vicinity of the orbit. If one is operating on the dermal side of the eyelids to approach the orbital rim and/or orbital floor, a temporary tarsorrhaphy (see Fig. 16-17 B and C ) or scleral shell (see Fig. 16-17 A ) may be used after application of a bland

eye ointment.¹²³ These are simply removed at the completion of the operation.

Diluted epinephrine solutions are used before incision for two reasons. The first is the hemostasis that they provide. The second is to separate the tissue before incision intentionally. This latter use becomes important when one operates on the thin eyelids. The solutions can be used to cause the tissue to balloon out, facilitating incision. One must remember, however, to mark the line of incision before injecting the solution into the eyelids, because the tissue will be distorted and a perceptible crease may disappear following injection.

Maxillary Vestibular Approach

The maxillary vestibular is one of the most useful approaches for open treatment of ZMC fractures. Access to the entire facial surface of the midfacial skeleton— from the zygomatic arch to the infraorbital rim to the frontal process of the maxilla—can be achieved in a relatively safe manner through this approach. Its greatest advantage is the hidden intraoral scar that results. This approach is also relatively rapid and simple, and complications are few.

Technique. The length of the incision and amount of subperiosteal dissection depend on the area of interest and extent of surgery. If one is interested in only half of the midface—for example, with a unilateral ZMC fracture—the incision can be made on one side only, leaving the other side intact. Submucosal injection of a vasoconstrictor can reduce the amount of hemorrhage during incision and dissection. The incision is usually placed approximately 3 to 5 mm superior to the mucogingival junction. The incision extends as far posteriorly as necessary to provide exposure, usually to the first molar tooth, and traverses mucosa, submucosa, facial muscles, and periosteum. Periosteal elevators are used to elevate the tissue in the subperiosteal plane. Almost no anatomic hazards exist except the infraorbital neurovascular bundle above and the posterosuperior alveolar vessels along the posterior maxilla, which infrequently cause bleeding. The entire anterior face of the zygoma can be easily exposed. Fractures through the infraorbital rim, anterior maxilla, and zygomaticomaxillary buttress can easily be identified and treated (see Fig. 16-18).

Restitution of the nasolabial muscles should be performed as three uniform steps during closure of the maxillary vestibular incision. The first step involves identification and resetting of the alar bases, the second involves eversion of the tubercle and vermilion, and the third involves closure of the mucosa. To help control the width of the alar base, an alar cinch suture is placed before suturing the lip. A V-Y advancement closure of the

PART III Management of Head and Neck Injuries maxillary vestibular incision is recommended where the incision has been placed across the base of the nose and subperiosteal dissection of the tissue along the piriform aperture has occurred. When closing the horizontal incision, one should begin in the posterior and work anteriorly with running resorbable sutures (3-0 chromic catgut) through the mucosa, submucosa, musculature, and periosteum. The superior aspect of the incision is gradually advanced toward the midline by passing the needle anteriorly in the lower margin of the incision as compared with the upper margin. This maneuver, in addition to the V-Y closure, helps lengthen the relaxed musculature so that it reattaches in its proper position.

Supraorbital Eyebrow Approach

A popular approach used to gain access to the lateral orbital rim is the eyebrow incision (Fig. 16-20). No important neurovascular structures of any significance are at risk when this approach is used, and it provides simple and rapid access to the frontozygomatic area. Because the incision is made almost entirely within the confines of the eyebrow, the scar is usually imperceptible. However, the scar will not be hidden in those who have no eyebrows extending laterally along the orbital margin. In this case, another incision is indicated. An additional disadvantage of this approach is that it does not afford a great amount of surgical access.

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Technique. Before incising the skin, the surgeon should palpate the lateral orbital rim to reveal the location of the fracture site. It is usually in the frontozygomatic suture area, which is at the interolateral aspect of the eyebrow. However, the fracture may be more inferiorly positioned, and in that case the incision may need to be placed a given amount below the eyebrow.

The surgeon supports the skin over the orbital rim using two fingers and a 2-cm incision is made. It should be stressed that there is no reason to shave the eyebrow before incision because the hair may not grow back. The incision should be parallel to the hair of the eyebrow to prevent cutting hair shafts, which also may retard the growth of eyebrow hair. The incision is made to the depth of the periosteum in one stroke and, after minimal undermining, another incision through the periosteum completes the sharp dissection.

Two sharp periosteal elevators are used to expose the lateral orbital rim on the lateral, medial (intraorbital), and posterior (temporal) surfaces. The fracture is usually located at the inferior extent of the wound; this location necessitates wide undermining of the periosteum to allow the tissue to be retracted inferiorly to provide better access to the fracture (see Fig. 16-20 B ). It should be noted that if one stays in the subperiosteal space, there is almost no chance of damaging vital structures. The incision is closed in two layers, the periosteum and skin.

Upper Eyelid Approach

The upper eyelid approach to the superolateral orbital rim is also called the upper blepharoplasty, upper eyelid crease, and supratarsal fold approach. In this approach, a natural skin crease in the upper eyelid is used to make the incision (Fig. 16-21 A ). The advantage to this approach is the inconspicuous scar it creates, rendering it one of the best approaches to the region of the superolateral orbital complex.

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Technique. If the tissue is edematous, the skin surrounding the opposite orbit can be used to obtain an appreciation of the direction of the creases. If a lid crease is not readily detectable, a curvilinear incision along the area of the supratarsal fold that trails off laterally over the lateral orbital rim works well. The incision should be similar in location and shape to the superior incision in a blepharoplasty. However, the incision may be extended farther laterally as necessary for surgical access. The incision should begin at least 10 mm superior to the upper lid margin and be 6 mm above the lateral canthus as it extends laterally. The incision is through both the skin and orbicularis oculi muscle. The surgeon develops a

skin-muscle flap superiorly, laterally and, if necessary, medially, using scissor dissection in a plane deep to the orbicularis oculi muscle. The dissection is carried over the orbital rim, exposing periosteum. The skin-muscle flap is retracted until the area of interest is exposed. The periosteum is divided 2 to 3 mm posterior to the orbital rim with a scalpel. Periosteal elevators are used to perform subperiosteal dissection of the orbit and orbital rims (see Fig. 16-21 B ). The wound is closed in two layers, periosteum and then skin and muscle.

Lower Eyelid Approaches

Several approaches to the orbit through the skin surface of the lower eyelid have been described. They differ in the level at which the skin incision is made and level of dissection to the infraorbital rim. The subtarsal approach is one of the more frequently used approaches for access to the infraorbital rim and orbital floor. The subtarsal incision is made in a natural skin crease at or below the level of the tarsus, approximately half the distance between the lash margin and orbital rim (Fig. 16-22). It extends laterally and inferiorly, similar to the skin creases. The main advantages of the subtarsal approach are the following: (1) it is relatively easy; (2) the incision is placed in a natural skin crease so that the scar is imperceptible; and (3) it is associated with minimal complications. It has few disadvantages.

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The subciliary approach, also called the infraciliary approach, or blepharoplasty, has been favored by a number of U.S. surgeons over the past 20 years. The skin incision is made approximately 2 mm inferior to the gray line of the lower eyelid, along the entire length of the lid (see Fig. 16-22). The incision may be extended laterally approximately 1 to 1.5 cm in a natural crease inferior to the lateral canthal ligament. The main advantage to this incision is the imperceptible scar that it creates. The disadvantages are the following: (1) the procedure is technically difficult for the novice; and (2) a higher risk of postoperative ectropion exists.^109,124-128

Dissection Technique for the Subciliary or Subtarsal Approach. After the skin has been incised, the surgeon has three options. The first is to dissect between the skin and muscle until the orbital rim is reached, at which point another incision through muscle and periosteum to bone is made (Fig. 16-23 A ). The second option is to incise through muscle at the same level as the skin incision and dissect down just anterior to the orbital septum to the orbital rim (see Fig. 16-23 B ). The third option is a combination of these, in which subcutaneous dissection toward the rim proceeds for a few millimeters and is followed by incision through the muscle at a lower level, producing a stepped incision, with dissection then

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PART III Management of Head and Neck Injuries following the orbital septum to the rim (see Fig. 16-23 C ).¹²⁹ Fine scissors are useful during the dissection to the infraorbital rim no matter which option is chosen, with the surgeon using a spreading motion.

Although advocated by a number of surgeons, each option has advantages and disadvantages. The first option, in which the surgeon makes a subcutaneous dissection producing a skin flap to the level of the rim, leaves an extremely thin skin flap. It is a technically difficult flap to elevate, and accidental buttonhole dehiscence can occur. A further problem that may occasionally be seen is a slight darkening of the skin in this area following healing. Presumably, the thin skin flap becomes avascular and acts essentially as a skin graft. An increase in the incidence of ectropion has also been noted, as opposed to when the dissection is made deep to the orbicularis oculi.¹²⁶ Entropion, lash problems, and skin necrosis have occasionally been experienced after the skin-only flap.⁷⁷ The second option, in which the dissection is made between muscle and orbital septum, is technically less difficult. Care must be taken, however, because the thin orbital septum can be easily violated, resulting in periorbital fat herniating into the wound. The skin and muscle flap, however, presumably maintains a better blood supply and pigmentation of the lower lid has not been a finding.¹³⁰ The third technique, in which a layered dissection is used, is probably the simplest of the three and prevents the disadvantages of the others. An added advantage of leaving a 4- to 5-mm strip of muscle attached to the lower tarsus is that if it remains functional, it may help maintain the position of the lower eyelid on the globe.

With any of these techniques, the incision through the periosteum should be placed 3 to 4 mm below the orbital rim to prevent insertion of the orbital septum along the orbital margin. Subperiosteal dissection exposes the subciliary incision can also be used to expose the lateral orbital rim. When the incision is used for this purpose, lateral extension of the skin incision for 0.5 to 1 cm and wide subperiosteal dissection permit the necessary access to the lateral aspect of the orbit, up to and including the frontozygomatic suture.¹³¹ In the process of subperiosteal dissection, the lateral palpebral ligament and suspensory ligaments are stripped from the orbital tubercle of the zygoma. This stripping presents no apparent problem if the injury is acute and the periosteal tissue is securely sutured at the completion of the operative procedure. This technique is not recommended for the inexperienced surgeon because it can be fraught with difficulties in access and postoperative swelling. Properly performed, however, it is an excellent method for simultaneously exposing the infraorbital and frontozygomatic areas, and healing produces an imperceptible scar. Exposure of the lateral orbital rim via a subtarsal incision is not recommended because the lateral portion of the incision is usually some distance inferior to the orbital rim.

Closure should be in at least two layers, the periosteum and skin. Attempting to suture the orbicularis oculi is difficult and of little value. The running subcuticular suture is an excellent suture for the thin skin of the eyelid.

Transconjunctival Approach

The transconjunctival approach, also called the inferior fornix approach, was originally described by Bourguet in 1928.¹³² Two basic transconjunctival incisions have since been described, the preseptal and retroseptal approaches, which vary in the relationship of the orbital septum to the path of dissection (Fig. 16-24). Tenzel and Miller¹³³ have developed the transconjunctival retroseptal incision and Tessier¹³⁴ elaborated on the transconjunctival preseptal incision (see Fig. 16-24 B ). The retroseptal approach is more direct than the preseptal approach and is easier

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to perform (see Fig. 16-24 A ). Converse et al¹³⁵ have added a lateral canthotomy to the transconjunctival retroseptal incision for improved lateral exposure. The advantage of the transconjunctival approaches is that they produce superior cosmetic results when compared with any other commonly used incision because the scar is hidden behind the lower lid. Other advantages are the following: (1) these techniques are rapid; and (2) no skin or muscle dissection is necessary. In a study by Wray et al,¹²⁶ in which the transconjunctival approach was used for orbital floor and rim fractures, lateral canthotomy was necessary for improving access in 56% of approaches.

Technique for Retroseptal Transconjunctival Approach Combined With Lateral Canthotomy. In any transconjunctival approach, the cornea must be protected. Because a tarsorrhaphy is precluded, a corneal shell should be placed to protect the globe (see Fig. 16-17 A ). The lower eyelid is everted by two traction sutures placed through the tarsal plate. The surgeon performs a lateral canthotomy as the initial step by inserting one end of sharp iris scissors into the lateral palpebral fissure and cutting through in a horizontal (lateral) direction (see Fig. 16-24 C ). With eversion of the lid margin by the traction suture, the scissors are directed inferiorly to transect the inferior portion of the lateral canthal tendon (inferior cantholysis; see Fig. 16-24 D ). When transection is completed, the eyelid will fall away freely. The scissors are then used to undermine the palpebral conjunctiva just below the tarsus. The conjunctiva can be undermined medially to the lacrimal punctum. One beak of the scissors is brought out of the pocket and the conjunctiva and lower lid retractors are incised (see Fig. 16-24 E ). A suture can be passed through the incised conjunctiva in the fornix and used to retract the tissue superiorly. Blunt dissection toward the orbital rim is performed with scissors while the lower eyelid is being retracted anteriorly. With retraction of the globe and retraction of the lower eyelid, an incision is made with a scalpel through the periorbita, just posterior to the orbital rim (see Fig. 16-24 F ). A broad malleable retractor should be placed as soon as feasible to protect the globe and confine the periorbital fat. Subperiosteal dissection of the orbital

PART III Management of Head and Neck Injuries contents can then proceed. To facilitate retraction of the lower eyelid, the periosteum can be dissected anteriorly over the orbital rim and a few millimeters onto the face of the maxilla.

The periosteum may be difficult to close; some surgeons do not attempt closure of this layer.¹³⁶ The transconjunctival incision is closed with the use of running 6-0 gut sutures; the inferior limb of the lateral canthal tendon and tarsal plate is sutured to the inner aspect of the lateral orbital rim using 4-0 slowly resorbing or nonresorbing sutures (see Fig. 16-24 G ). Placement of these sutures is critical to adapting the lower eyelid to the globe properly. The surgeon should pass the suture along the medial side of the lateral rim of the orbit, attempting to pass it through the superior portion of the lateral canthal tendon, which is still attached to the lateral orbital tubercle. The small skin incision at the lateral canthus is closed with 6-0 sutures.

Coronal Approach

The coronal, or bifrontal, flap, modified to include some of the advantages of the modified preauricular flap of

Al-Kayat and Bramley,¹³⁷ is an extremely useful incision for surgery of the zygoma and arch. Although it may initially appear as a radical approach to the management of zygomatic fractures, it provides excellent access to the orbits, zygomatic bodies, and zygomatic arches, with almost no complications.¹³⁸ It is an extremely useful incision if there is comminution of the supraorbital and lateral orbital rims, and zygomatic body and arch. The scar produced is hidden within the hairline and is therefore invisible.

Technique. In contrast with the earlier practice of extensive shaving of the head before incision, shaving the hair from the operative field is unnecessary, other than for surgical convenience. A 2-cm strip of hair can be removed in the immediate area of the incision and the adjacent hair prepped. If the hair is long, it can be tied off in clumps with sterile elastics (once prepped) to minimize the annoyance of loose hair in the operative field during the procedure. The drapes can be sutured or stapled to the scalp, covering the posterior scalp and confining this hair. For bilateral procedures, a strip across the superior aspect of the head is shaved.

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In placing the incision, two factors should be borne in mind. The first is the hairline of the patient, not just the present but the anticipated future hairline. In males, minor recession of the hairline with age may make the scar visible if it is placed just behind the hairline. Therefore, the incision should be placed along a line extending from one preauricular area to the other, several centimeters behind the hairline (Fig. 16-25 A ). The incision can even be made farther posteriorly if necessary, without a significant reduction in access to the operative field. The second factor that should be considered is the amount of inferior access required for the procedure. Usually, the coronal incision may extend inferiorly to the level of the anterior border of the helix. If necessary, the coronal incision can be extended inferiorly to the level of the lobe of the ear, providing improved access at the inferior portion of the wound when necessary for zygomatic arch and infraorbital exposure.

The incision is made with a no. 10 blade through skin, subcutaneous tissue, and galea. At this point, the surgeon encounters a plane of loose areolar connective tissue overlying the pericranium (see Fig. 16-25 B ). The flap margin can be rapidly and easily lifted and dissected from the pericranium within this plane. On incision, the anterior and posterior wound margins are elevated for 1 to 2 cm to allow for the application of hemostatic clips (Raney clips), which prevent continuous bleeding from the vascular scalp throughout the procedure. Little hemorrhage should be encountered throughout the remainder of the procedure, although small vessels running through the pericranium from the skull may require cauterization. The anterior flap is elevated from the pericranium with finger dissection or the use of a blunt periosteal elevator. Along the lateral aspect of the skull, the temporal fascia becomes visible where it inserts into the pericranium, with the plane of dissection superficial to it. Once the flap has been elevated to within approximately 2 cm of the body of the zygoma and zygomatic arch, these structures can usually be seen through the covering fascia. The superficial layer of temporal fascia is incised approximately 2 cm superior to the zygomatic arch, beginning at the root of the zygomatic arch and continuing anteriorly and superiorly (see Fig. 16-25 C ). On incision of the superficial layer of temporal fascia, a layer of fat and areolar tissue is encountered (see Fig. 16-25 D ). Further dissection inferiorly at this level provides safe access to the zygomatic arch. From the root of the zygomatic arch, a periosteal incision is then made along the superior aspect of the arch and it is exposed subperiosteally (see Fig. 16-25 E ). The pericranium is now incised across the forehead and down along the lateral orbital rim. The periosteal incision at the lateral rim is connected to that over the zygomatic arch. Periosteal elevation then exposes the frontozygomatic fracture line and is continued around the lateral orbital rim into the orbit. The infraorbital rim can also be visualized to some extent with wide undermining. If access to the infraorbital area is necessary, the zygomatic arch and body should be thoroughly dissected before exposing the infraorbital areas to relax the tissue.

After fracture reduction and fixation have been accomplished, the wound is closed in layers. A lateral canthopexy is performed by drilling a hole through the lateral orbital rim just below the frontozygomatic suture for the passing of the suture. The suture can be secured to the temporal fascia or tied to the bone plate or wire in the zygoma at the frontozygomatic suture area. The periosteum over the zygomatic arch is difficult to close, and passing the suture may damage the temporal branch of the facial nerve. Instead, closure of the incised temporal fascia is performed (see Fig. 16-25 F ). The scalp incision is closed in two layers with the use of 2-0 sutures through the galea and sutures or staples on the skin surface. The use of a flat suction drain is optional. The skin sutures or staples are removed in 7 to 10 days.

REDUCTION TECHNIQUES

Temporal Approach

An approach that has been popular through the years for reduction of ZMC and zygomatic arch fractures is the temporal approach. First described by Gillies et al in 1927¹ for use in zygomatic arch fractures, this approach has proven versatility for zygomatic arch and ZMC fractures. One of its greatest advantages is that it allows the application of great amounts of controlled force to disimpact even the most difficult zygomatic fractures. It is, therefore, especially useful in late treatment of a fracture, when partial consolidation has already occurred. The Gillies temporal approach is also a quick and simple method, rarely requiring more than 15 to 20 minutes unless fixation techniques are necessary.⁸¹ The temporal approach is associated with few complications. Although the middle temporal veins may be encountered during instrumentation,¹³⁹ the hemorrhage encountered is rarely of any consequence.

Some have noted that this technique should be reserved for zygomatic arch fractures only, being ineffective for displaced or rotated zygomatic body fractures.^36,76 An overwhelming majority of surgeons, however, disagree with this presumption and use the Gillies temporal approach as the main method for reducing zygomatic fractures.*

Technique. A 3- × 3-cm area of hair is shaved approximately 2.5 cm above and 2.5 cm anterior to the helix of the ear. It is unnecessary to isolate the area completely from adjacent hair. A cotton pellet is placed within the external auditory canal to prevent blood from entering during surgery. Frequently, the bifurcation of the superficial temporal artery is visible once the area has been shaven and serves as an excellent landmark for incision. A 2.5-cm incision is made through the skin and subcutaneous tissue at an angle running from anterosuperior to posteroinferior in the area previously shaved. This incision can usually be placed superior to the bifurcation of the superficial temporal artery, between—and thereby avoiding—both branches. The incision is carried down through skin and subcutaneous tissue until the white glistening surface of the temporalis fascia is visualized (Fig. 16-26 A ). This incision can usually be performed

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*References 13, 15, 18, 19, 22, 24, 26, 28, 29, 33, 35, 81, 101, 102, 106, and 140-142.

with one stroke of the scalpel. At this level, one should be above the point where the temporalis fascia splits into two layers, one attaching laterally and one medially to the zygomatic arch. It is important that the incision be above this point of bifurcation so that the elevator can be easily placed medial to the zygomatic arch. If the incision is below the layer of temporal fascia bifurcation, the elevator will be placed within the space above the arch and medial placement will be difficult.

After exposure of the temporal fascia has been completed, a second, deeper incision is carefully made the full length of the skin incision through the fascia (see Fig. 16-26 B ). At this point, one should see the underlying temporalis muscle bulge through the incision. If this is not seen, the possibility of the incision being placed too low and into the space above the arch should be suspected. In this case, the incision should be deepened until the temporal muscle is visible. Remember that the temporalis muscle is the key structure in this dissection. A flat instrument, such as a large Freer elevator or the broad end of a no. 9 periosteal elevator, is then inserted between the temporalis muscle and temporalis fascia (see Fig. 16-26, C ). The instrument is swept back and forth as the tip is moved inferiorly until the medial aspect of the zygomatic arch and infratemporal surface of the body of the zygoma are felt. The instrument should glide freely in this plane because there is no dense attachment between the temporal muscle and temporal fascia. It may be difficult, however, to pass the instrument medially to the zygomatic arch if medial displacement has occurred, especially in areas of fracture. In this case, the tip of the instrument must be pressed medially until the medial aspect of the zygomatic arch is reached. The entire extent of the arch and zygomatic body should be palpated with the instrument to determine the location and extent of fractures. Bimanual palpation with one hand placed externally over the soft tissue of the side of the face is frequently helpful.

The periosteal elevator is removed and a flat instrument of sufficient rigidity is inserted into this same plane to reduce the fracture. Originally, a Bristow elevator was used and it was necessary to use the superior margin of the wound and adjacent skull as a fulcrum to obtain the leverage necessary for reducing the fracture. It was necessary to place gauze under the instrument at the point of fulcrum to prevent bruising the scalp. Although this instrument can still be used, it should be used with care because damage to the cranium has occurred.¹⁴³ An ingenious instrument that has since been designed for zygomatic elevation, and allows one to exert large amounts of controlled force without using the skull as a fulcrum, is the Rowe zygomatic elevator (see Fig. 16-26 D ). It has a flat blade on its working end for insertion medial to the zygomatic arch and body. It has two handles for grasping during use. The first handle is in a direct line with the working end and is used primarily for stabilization. The second handle is on the external lifting lever, which is in turn attached to the area of the stabilizing handle. When the stabilizing handle is kept in one position and the lifting handle is activated, the working blade can generate large amounts of force beneath a zygoma. The instrument was designed so that the two arms are approximately the same length. With this feature, the surgeon can be constantly aware of the depth of insertion of the working blade by collapsing the hinge between the two arms and seeing where the external handle lies in relation to the zygoma (see Fig. 16-26 E ).

Once the Rowe zygomatic elevator is in position at the proper depth, the external handle is elevated as the other handle stabilizes the working blade position. Firm anterior, superior, and lateral elevation is applied to the body of the zygoma in cases of ZMC fractures or to the arch in cases of arch fractures (see Fig. 16-26 F and G ). During elevation, an assistant must palpate the frontozygomatic and infraorbital areas while steadying the head against the elevator’s pull. An audible crunch or crack usually accompanies the elevation. If strong resistance is felt, one must consider that the zygoma is greatly impacted, in which case more force may be necessary, or that the tip of the elevator may have been placed too far medially through the temporal muscle. In the latter case, one may be applying elevation to the coronoid process or medial aspect of the ramus of the mandible. Once the body of the zygoma has been elevated, the instrument’s working blade should be swept posteriorly and laterally, reducing or ironing out any zygomatic arch fractures. The surgeon must then verify that any steps at the osseous zygomatic processes have been eliminated. Once verification of adequate reduction and resistance to displacement has been accomplished, the elevator is withdrawn and the incision is closed in one or two layers.

Buccal Sulcus Approach

Another popular technique for the reduction of zygomatic fractures is the approach through the maxillary buccal sulcus. Keen published an article on this technique in 1909¹⁴³ and it is favorably used by many surgeons today.^36,144 The major advantage, as in most intraoral approaches, is the prevention of any external scar. The buccal sulcus approach can be used for both ZMC and zygomatic arch fractures. Although the use of this approach for elevation has several laudable attributes, unstable fractures may require external incisions for the application of stable methods of fixation.

≈ Keen Technique. A small incision ( 1 cm) is made in the mucobuccal fold, just beneath the zygomatic buttress of the maxilla. The incision can be made from anterior to posterior or from medial to lateral and should extend through mucosa, submucosa, and any buccinator muscle fibers. The sharp end of a no. 9 periosteal elevator or curved Freer elevator is inserted into the incision. Using a side to side sweeping motion, the surgeon makes contact with the infratemporal surface of the maxilla, zygoma, and zygomatic arch and dissects the soft tissue in a supraperiosteal manner. A heavier instrument can then be inserted behind the infratemporal surface of the zygoma and, using superior, lateral, and anterior force, the surgeon reduces the bone (Fig. 16-27 A ). The use of one hand over the side of the face to assist in the reduction procedure is extremely helpful. One should take care to avoid using the anterior maxilla as a point of fulcrum.

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Several different instruments can be used to accomplish this maneuver, including those designed specifically

for this purpose, such as the Monks or Cushing (joker) elevator. However, any suitable instrument of sufficient rigidity with a bend on the end to engage the infratemporal surface of the zygoma can be used. A right angle retractor, bone hook, large Kelly hemostat, or urethral sound are satisfactory instruments for this purpose. Another instrument that can be used successfully through the buccal sulcus approach is a simple dental extraction forceps (see Fig. 16-27 B ). It is used in a manner similar to a Rowe zygomatic elevator in that the hinge portion of the forceps is the stabilizing handle and one of the forceps handles is the elevating handle. The other forceps handle becomes the working end and engages the posterior aspect of the zygoma. Controlled force can be easily applied in this manner.

A flat instrument, such as a Seldin retractor, can then be used to follow the medial surface of the zygomatic arch and elevate it laterally, if necessary. This same approach is used on isolated zygomatic arch fractures. It must be stressed that when the temporal surface of the zygomatic body is followed laterally, one must stay close to bone or the instrument may become placed on the medial side of the coronoid process. Although some clinicians think that the intraoral approach cannot be used effectively for zygomatic arch fractures,^81,145 this has not been the experience of all. The incision in the mucobuccal fold does not have to be sutured.

Lateral Coronoid Approach

In 1977, Quinn¹⁴⁶ described a lateral coronoid approach for the reduction of zygomatic arch fractures. This approach is not useful for fractures of the ZMC but is a simple method for isolated fractures of the arch. A 3- to 4-cm intraoral incision is made along the anterior border of the ramus through the mucosa and submucosa. The incision is not made down to the bone but to the depth at which the temporal muscle inserts on the ramus. The wound is deepened superiorly, following the lateral aspect of the temporal muscle with blunt dissection. This route of dissection will bring the instrument (or finger) between the temporal muscle and zygomatic arch, which should be readily palpable. The buccal fat pad will probably be encountered but is of no concern. A flat-bladed heavy elevator is inserted into this pocket, with the surgeon taking care to ensure its proper placement lateral to the coronoid process, and the arch is elevated while the surgeon palpates extraorally along the arch (see Fig. 16-27 C ). The wound is closed in one layer.

Elevation from Eyebrow Approach

In the United States, a popular technique for the elevation of zygomatic fractures is the eyebrow incision (described earlier).^17,81,76,147 The advantage to this technique is that the fracture at the orbital rim is visualized directly and fixation of the fracture at this point can be undertaken through the same incision, when necessary. The disadvantage is that it is difficult to generate a large amount of force, especially in the superior direction.^9,36,102

Technique. Once exposure of the fracture at the frontozygomatic area of the lateral orbital rim has been accomplished, a heavy instrument is inserted posteriorly to the zygoma along its temporal surface. The instrument is then used to lift the zygoma anteriorly, laterally, and superiorly while one hand palpates along the infraorbital rim and body of the zygoma (Fig. 16-28 A ). Useful instruments for this purpose are the Dingman zygomatic elevator, urethral sound, or even large Kelly hemostat. The

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388 PART III Management of Head and Neck Injuries

arch can also be approached from this exposure and reduced (see Fig. 16-28 B ).

Percutaneous Approach

A direct route to elevation of the depressed zygoma is through the skin surface of the face overlying the zygoma. This approach has been used extensively worldwide. The advantage to the technique is that one can produce forces anteriorly, laterally, and superiorly in a direct manner, without having to negotiate adjacent structures with the instruments. The major disadvantage is a scar on the face in a very noticeable location. However, in practice, scarring is more a theoretical than real disadvantage because the incision sites are rarely visible 2 to 3 weeks after surgery.

Technique. The percutaneous approach is probably the simplest of all techniques because no soft tissue dissection is necessary. Several instruments can be used to elevate the zygoma. The bone hook, introduced by Strohmeyer in 1844,¹⁴⁸ has probably been the most widely used instrument and is advocated by many (Fig. 16-29 A ).* The point of the hook is simply inserted through the soft tissue of the malar area at a point just inferior and posterior to the prominence of the zygoma so that it engages the infratemporal aspect (see Fig. 16-29 B ). Poswillo¹⁵² draws two intersecting lines on the face to determine the proper location for application of the bone hook. The first is a vertical line dropped from the lateral canthus of the eye. The second is a horizontal line drawn laterally from the ala of the nose. A small stab incision is made at the point of intersection of these lines and the hook is inserted. The hook is then rotated to engage the temporal surface of the zygoma. One must be cognizant of the

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*References 25, 103, 104, 109, 110, 149-153.

area of application of the point of the hook on the back of the zygoma, ensuring that the hook has not slipped into the inferior orbital fissure, which can cause venous hemorrhage that might result in ocular injury. Strong traction in any direction can then be applied to reduce a displaced zygoma (see Fig. 16-29 C ).

A large bone screw, such as the Carroll-Girard screw, is another instrument that has been used with some frequency for elevating zygomas (Fig. 16-30). It resembles an elongated corkscrew with a T bar handle and contains threads on its working end. This screw can be threaded into the body of the zygoma following placement of a hole and can then be used as a handle to reduce the displaced zygoma (see Fig. 16-30 B ). An advantage to its use is that one can control the ZMC position in all three planes of space.

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Any of these instruments (and probably others) are helpful when the clinician uses the transcutaneous approach to the zygoma. The possible application of one or two monofilament sutures is all that is necessary to care for the wounds created by their use.

FIXATION TECHNIQUES

The application of plate and screw fixation techniques to ZMC fractures has replaced all the older techniques of fixation. There is no better method of providing stable fixation to an unstable ZMC fracture than to secure it rigidly internally with bone plates and screws. The obvious advantage to bone plates is that stabilization in three planes of space can be provided, even across areas of comminution or bone loss.

Each case must be individualized, because the fixation requirements differ greatly from one fracture to the next. Some fractures may require no fixation; others may require three or four bone plates. When plate and screw

fixation is used, there are general principles of its application for ZMC fractures.

1. Use self-threading bone screws. The thin bones of the midface lend themselves to the application of self-threading screws. It has been shown that selfthreading screws have more holding power in thin bones than when the holes are tapped.^154-157

2. Use hardware that will not scatter postoperative CT scans. Titanium plates and screws have the advantage of not causing scatter in CT scans. Vitallium causes more scatter, so if it is selected, smaller plates and screws should be used to minimize CT artifacts.^158-161

3. Place at least two screws through the plate on each side of the fracture. The three-dimensional stability provided by plate and screw fixation demands that

the bone plate be adequately secured to each fragment. At least two screws are necessary for stabilizing a bone plate to a bone fragment.

4. Avoid important anatomic structures. One should position bone plates so that the screws do not impale structures, such as the tooth roots and infraorbital nerve. If the fracture through the zygomaticomaxillary buttress is low, one should select an L-, a T-, or Y-shaped bone plate so that both of the lower screws are positioned horizontally in the alveolar process. The use of straight plate in this case might cause the lower screw to impale a tooth root (Fig. 16-31).

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5. Use as thin a plate as possible in the periorbital areas. The skin overlying the orbital rims is very thin and becomes more so over time. If a bone

PART III Management of Head and Neck Injuries plate must be placed along the orbital rim, it should be extremely thin to prevent visibility and reduce palpability. This is especially true of the infraorbital rim. If possible, one may wish to avoid placing bone plates in this location unless absolutely necessary.

6. Place as many bone plates in as many locations as necessary to ensure stability. Many fractures can be adequately stabilized with a single bone plate applied at the frontozygomatic area* or at the zygomaticomaxillary buttress^{95,99,100,113} (see earlier). However, when the articulations between the ZMC

*References 52, 88, 79, 89, 108, 109, 111, and 161.

• and adjacent bones are comminuted, it will be necessary to apply additional bone plates in additional areas. One can determine how much fixation is necessary by forcefully trying to displace the repositioned ZMC during surgery. This maneuver is especially easy if a Carroll-Girard screw has been inserted. If the ZMC is stable against the application of moderate force, it is unlikely that postreduction displacement will occur and no more fixation is necessary. If there is some mobility after the application of a bone plate, another plate may be necessary.

7. If concomitant fractures of other midfacial bones exist, it will be necessary to apply fixation devices more liberally. For example, if the maxillary alveolus, hemimaxilla, or complete maxilla is unstable, a bone plate at the zygomaticomaxillary buttress will no longer be able to provide the primary means of support for the repositioned ZMC. In such cases, primary fixation of the frontozygomatic area will be necessary. It is imperative that the dentition be placed into maxillomandibular fixation before bone plates are applied when concomitant maxillary fractures are present.

8. In areas of comminution or bone loss, span the gap with the bone plate. Comminution of fractures through the zygomaticomaxillary buttress and infraorbital rim is common. If small bone fragments are missing, it is imperative that the gap be maintained by the bone plate; otherwise, the ZMC will be malpositioned. When the gaps are more than a few millimeters, bone grafts can be attached to the bone plate or laid (and stabilized) over the bone plate to promote osseous healing across the defect.

In the treatment of ZMC fractures, internal orbital reconstruction is a supplementary procedure that is frequently but not always indicated. When indicated, internal orbital reconstruction is a vital component of treating ZMC fractures (Fig. 16-32). The complications of ZMC fractures that are most difficult to correct secondarily are those of the orbit. When internal orbital reconstruction is not performed when indicated, or is performed inadequately (see Fig. 16-14), postsurgical enophthalmos can result.

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Postsurgical enophthalmos is one of the most distressing complications after treatment of ZMC fractures. It usually results if the orbital floor and walls have not been reconstructed when indicated or have been inadequately reconstructed.^{88,91,162-167} Studies have shown that posttraumatic enophthalmos is most commonly caused by an increase in the size of the bony orbit.^66,67 Lateral positioning of the ZMC is one of the most effective methods for increasing orbital volume because of the cross-sectional area of the orbit at the level of the displaced ZMC. However, concomitant fractures of the orbital floor and/ or medial wall are common with ZMC fractures and can also increase orbital volume.¹⁴⁷

Any patient with presurgical enophthalmos should be suspected of having orbital disruption but traumatic edema may mask the problem, making clinical examination difficult. CT has made preoperative assessment of the status of the bony orbit possible, with a great degree of accuracy. In reviewing treatment of ZMC fractures over a 10-year period, Covington et al⁷⁹ found a reduction in orbital exploration from 90% in 1985 to 30% in 1989 because of the increasing use of preoperative CT

INTERNAL ORBITAL RECONSTRUCTION

scans. Studies have shown that the CT scan allows predictable determination preoperatively of whether the orbital floor and/or walls require reconstruction.^114,118 This information permits more comprehensive preoperative planning of the surgery and avoids unnecessary orbital exploration. The availability of intraoperative CT scanning in some operating rooms will also affect the decision about when internal orbital reconstruction is necessary.

Intrasinus Approach to the Orbital Floor

The antral approach to the orbital floor historically has been predicated on the ability to realign the orbital floor without making external incisions when the orbital floor has been depressed but there is no herniation of soft tissue through the periorbita. Packing the sinus with gauze or a balloon to provide support to the orbital floor for 2 weeks was thought to allow healing to take place.^45,168- 172 In practice, however, this technique is rarely possible and should not be used as the routine approach to the

More recently, surgeons have begun to use an endoscope for evaluating and reconstructing the orbital floor.^173-178 Approaching the orbital floor through a bone window in the lateral maxilla allows the insertion of an endoscope to examine the status of the floor and, if necessary, reconstruct it by insertion of a material, such as bone, metallic mesh, or porous polyethylene into the orbital defect.

External Approach to the Internal Orbit

Reconstruction of the orbital floor is performed through a lower eyelid approach (subciliary, subtarsal, or transconjunctival). Using any of the approaches to the infraorbital rim and internal orbit (see earlier), the surgeon gently elevates the periorbita along the floor of the orbit. It must be remembered that the orbital floor is inferior to the level of the rim, so when the periorbita is elevated, one must be careful to follow the contour of the rim or perforation of the periorbita will occur. The subperiorbital dissection should extend beyond the full length of the access incision in the skin. Comminution of the infraorbital rim is commonly present. It is always easier to dissect the periorbita from sound bone toward the fractured areas. Protection of the periorbita and globe is facilitated after dissection by placement of a malleable retractor. The area of disrupted orbit may be a narrow crack along the floor, usually along the infraorbital groove, or severely comminuted floor and walls. When comminuted, it becomes difficult to dissect the periorbita from the thin bone spicules. One must continue dissection posteriorly along the orbital floor and medial wall until sound bone is found. Thus, dissection far posterior to the globe is usually necessary. Areas of periorbital fat dehiscence through the periorbita into the maxillary or ethmoid sinuses must be gently freed. Small bone spicules can be removed if free from soft tissue attachments.

For fractures in which the defect is a narrow linear groove, no reconstruction is usually necessary. When a larger defect is noted and the periorbita has been disrupted, reconstruction of the internal orbit is necessary

PART III Management of Head and Neck Injuries for preventing enophthalmos and ptosis of the globe (Fig. 16-33).

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A B · D · C

Materials Used for Orbital Reconstruction

A number of materials have been used to reconstruct the internal orbit, including autologous bone, autologous cartilage, allogeneic bone and cartilage, methyl methacrylate, silicone polymer, polyurethane, aluminum oxide ceramic, Teflon (polytetrafluoroethylene polymer), gelatin film (Gelfilm), Supramid, polyethylene, polyvinyl sponge, polydioxanone plates, polyglactin mesh or plates, polylactide plates, porous polyethylene, lyophilized dura, and metal sheets or mesh (Potter and Ellis have written a comprehensive review¹⁷⁹ ).

Bone has been used extensively for many years with excellent results and is often chosen when the orbital defect is large. Autologous bone can be obtained from a number of donor sites. Historically, the most common source was the iliac crest. However, split ribs, the anterior surface of the opposite maxilla, and the buccal or lingual cortex of the mandible have also been used with good success. From 1980 to 2000, the calvarium became one of the primary donor sites.^180-182 When bone is used, it should be borne in mind that some resorption will eventually take place, so adequate volume should be transplanted to offset this eventuality. Although the use of allogeneic bone and cartilage is less common, it may have merit.¹⁸³ The possibility of infection from the open sinus does not seem to be a problem with bone.

Although autologous grafts may appear to be ideal, there is associated donor site morbidity and increased operative time involved in graft harvesting and carving. Furthermore, calvarial bone grafts are difficult to shape and are brittle. These factors led to the development and acceptance of alloplastic substitutes for use in orbital reconstruction. Criticism directed at the use of alloplastic materials cites the complications of infection, extrusion, and implant displacement. There have been reports of

late complications developing with implanted silicone that have necessitated its removal as long as 18 years postoperatively.^184-194 Morrison et al¹⁹⁵ have reviewed 311 cases of silicone implants placed over a 20-year period and found that at least 13% required removal for one reason or another. However, when used in small defects and properly stabilized, silicone, Teflon, and other alloplasts have proven useful. Porous polyethylene has become popular in recent years for orbital reconstruction. It comes in various thicknesses, is easy to bend, and maintains its shape. Another advantage is that it offers sufficient rigidity to confine the orbital contents and can be stabilized easily with plate and/or screw fixation.¹⁹⁶

A major advantage to bone, cartilage, and bioresorbable products, such as gelatin film and polydioxanone or polyglactin plates, when compared with alloplastic implants, is that not only are they able to provide the necessary support to orbital tissue, but they are also incorporated or replaced in the body, minimizing the chance of late reactions. Gelfilm has been shown to undergo slow degradation over a 10-week period, with bone bridging occurring simultaneously in orbital floor defects created in adult rhesus monkeys.¹⁹⁷ Unfortunately, many of the biodegradable products are not stiff enough to be useful in large orbital defects.^198-202 In such cases, bone, porous polyethylene, or metallic implants should be considered.

Metallic mesh has become popular for orbital reconstruction in recent years.^203-208 Even though metallic mesh is exposed to open sinuses, it is rare to have to remove any because of infection. Advantages of the use of metallic mesh are that it can be made to conform to the desired contours, it is stiff enough to maintain adequate support of the periorbital tissue, and it is extremely thin. Also, it is readily visible on postoperative CT scans.

Principles of Orbital Implant and Transplant Placement

Because the objective of orbital reconstruction is to support the periorbital soft tissue and partition the maxillary or ethmoid sinuses from the orbit, any of the materials discussed will suffice. The decision is usually based on the availability of the products, preference of the surgeon and, most importantly, size of the defect. When the defect is large, autologous bone, porous polyethylene sheets, and metallic mesh are the materials of choice. The use of other materials, when the defect is large, necessitates a very large or thick implant, which would be difficult to stabilize along the minimal osseous margins. Alloplastic implants, such as silicone and Teflon, should be reserved for smaller defects. No matter which material is used, however, certain principles should be kept in mind.

1. The size of the implant or transplant. As large an implant or transplant as necessary for covering the entire defect should be used. The implant or transplant must be of sufficient size to be supported along most margins by sound bone. Before the placement of any implant or graft, one must be certain that its posterior edge is resting on sound bone. Perhaps the most common error in placement of an implant or transplant is leaving the

• posterior edge unsupported. To ensure proper placement, dissection back toward the orbital apex is necessary for establishing the posterior extent of the defect. If it is impossible to establish a sound posterior margin, the posterior edge of the material must be well supported laterally and medially. Alternatively the material can be cantilevered to adjacent sound bone with the use of plate and screw²⁰⁹

2. The thickness of the implant or transplant. The thickness of the implant or transplant is usually determined by the flexibility of the material. If flexible, a thicker piece is necessary for reconstructing a large defect without allowing sagging of the periorbital soft tissue into the sinus.

3. The volume of the implant or transplant. More bulk can be implanted if there is notable preoperative enophthalmos present. Most surgeons advocate the placement of more volume of implant or transplant than considered necessary for reestablishing the former position of the floor and walls. The added bulk should be posterior to the axis of the globe to displace it anteriorly. When bone is used, more than necessary is placed because remodeling and resorption will minimize its size (≈20% to 30%).¹⁸² The volume necessary is difficult to predict; however, postsurgical exophthalmos is rare.

4. Tension-free placement of the implant or transplant. The implant or transplant must be passive when inserted into the wound. In other words, there should be no tendency for an implant to buckle or for its edges to curl up or down, or for the implant to migrate when placed. If any of these occurs, the pocket is too small or the implant too large.

5. Stabilization of the implant or transplant. The implant or transplant must be fashioned so that it cannot be displaced or must be secured with sutures, wires, or bone screws (see Fig. 16-33 C ). Usually, orbital implants migrate anteriorly. This tendency is probably because the implant is improperly sized and placed under tension. The implant should not extend over the infraorbital rim. It usually can be placed so that its anterior end is behind the rim, with the rim acting as a physical impediment to anterior migration (see Figure 16-33, C ). Stabilization with bone screws and/or bone plates will prevent migration.²¹⁰

6. Careful closure of the wound. The periorbita must be carefully closed with resorbable sutures. This closure is extremely important because it ensures the proper positioning of the orbital septum and helps adapt the tissue over the implant or transplant.

PATIENTS TREATED FOR ZYGOMATICOMAXILLARY COMPLEX FRACTURES

It should be obvious from the earlier discussion and review of the literature that all ZMC fractures do not have to be treated in the same manner. Some require less surgical exposure and fixation than others.* The use of

*References 78, 87, 89, 99, 113, 114, and 118.

preoperative CT scans has allowed more accurate planning of treatment by identifying the severity of the injuries. Those that are severely displaced or segmented and/or have comminuted articulations usually require extensive internal orbital reconstruction. An aggressive approach to such fractures should be taken and should expose at least the zygomaticomaxillary buttress, infraorbital rim and internal orbit, and lateral orbital rim (Fig. 16-34). In many such cases, the zygomatic arch may also require exposure. The decision to use a coronal approach is based on the amount of displacement of the ZMC posteriorly and laterally and on comminution of the arch.^211,212 If the other articulations located more anteriorly appear to be significantly comminuted,

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exposure and reconstruction of the arch provide another point for reduction and stabilization.

Fractures that do not require internal orbital reconstruction (as determined by the preoperative or intraoperative CT scans) and whose articulations are not comminuted (as determined from the preoperative CT scan) can be treated less aggressively.^99,114,118 In such cases, the treatment algorithm presented in Figure 16-35 can be used. The first step is to elevate the ZMC into what is thought to be the proper position. The surgeon determines this position mainly through palpation of the articulations, visual assessment of malar projection, and/ or intraoperative CT scanning and/or navigation. Occasionally, an audible crunch will be heard and palpated when the ZMC is elevated into position. The most important step is to ensure that the ZMC is properly positioned. With minimal edema, the proper position is often easily ascertained by palpating the malar eminences bilaterally.⁴⁴ If the surgeon is unsure of the ZMC position, it is mandatory that exposure be performed to examine

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G H · K L

Reduce Fx

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M N · Reduced Unsure of redn · and stable Transoral open redn and/or unstable · STOP Unsure of redn · Reduced but unstable Open redn · FZ and lat orbit · Bone plate ZM buttress Bone plate FZ area

alignment with adjacent articulations. If one is satisfied with the position of the ZMC and it is firm in its position, as determined by the surgeon attempting to displace it, no fixation is required and no further surgery is necessary (Fig. 16-36). If the ZMC can be positioned properly but must be held in position, it must be stabilized.

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continued

In either of these cases, exposure of the zygomaticomaxillary buttress via the maxillary vestibular approach can be performed easily. The use of this approach as an initial point of exposure is predicated on the basis of the following: (1) the scar is hidden; (2) the access for reduction is good; and (3) if fixation is necessary, a bone plate placed on the zygomaticomaxillary buttress provides the best mechanical method of preventing postsurgical displacement in isolated ZMC fractures. After exposure of the entire face of the anterior maxilla and zygoma, a

PART III Management of Head and Neck Injuries broad surface area is visible for assessing alignment of the infraorbital rim and zygomaticomaxillary buttress. Because the ZMC is often comminuted, there will usually be an area in which the fractured zygomaticomaxillary buttress can be aligned with the alveolar process. If the ZMC is found to be reduced and stable, no further surgery is necessary. If the zygomaticomaxillary buttress can be aligned but rotates medially into the maxillary sinus when not supported, a single bone plate is placed at the zygomaticomaxillary buttress. If the ZMC is stable after this one point of fixation, no further surgery is necessary (Fig. 16-37).

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If the adequacy of reduction is still uncertain after exposure of the zygomaticomaxillary buttress, or if stability is not adequate even after placement of a bone plate on the zygomaticomaxillary buttress (unlikely), exposure of the frontozygomatic area is performed. The surgeon exposes the frontozygomatic area using an approach through the upper eyelid—an upper blepharoplasty incision. Although a lateral brow approach can also be used,

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the exposure provided is considerably less than with an upper eyelid approach unless the incision is extended below the eyebrow. However, this extension often results in a noticeable scar that crosses the resting skin tension lines. Alignment of the fracture through the frontozygomatic area and along the inside of the lateral orbital wall (sphenozygomatic suture area), when combined with alignment of the zygomaticomaxillary buttress, provides excellent assessment of reduction. Whether placement of fixation devices across the frontozygomatic fracture area is necessary is based on the ability to move the ZMC using the Carroll-Girard screw. If necessary, the type and amount of fixation are at the discretion of the surgeon. Because this area is readily palpable, very thin devices should be used. Thin bone plates or a transosseous wire may be all that is necessary when combined with a plate at the zygomaticomaxillary buttress. If the reduction and stability are judged to be adequate, no further surgery is necessary.

If one is still unsure of the reduction (unlikely for a low- or medium-energy injury), the infraorbital rim is exposed via an approach through the lower eyelid. The infraorbital rim can be aligned and, if necessary, stabilized with fixation devices. However, fixation devices in this area should be avoided unless absolutely necessary because of the thinness of the overlying tissue and the tendency for scar formation between the tissue of the lower eyelid and hardware. If fixation hardware is deemed necessary, the thinnest possible device should be used.

Fractures of the zygomatic arch are usually the result of fractures of the entire ZMC. However, isolated fractures of the arch without other injuries do occur when a force is applied directly from the lateral aspect of the head. The incidence of these injuries varies, but usually isolated zygomatic arch fractures constitute fewer than 10% of zygomatic injuries.²⁶ However, others have noted higher incidences, possibly related to the nature of the population.^12,36,76 Conceivably, many isolated zygomatic arch fractures may go unnoticed by the patient or are deemed of insufficient significance to seek treatment.

Isolated zygomatic arch fractures characteristically result in a V-shaped indentation of the lateral aspect of the face, with the apex deep toward the sigmoid notch (Fig. 16-38). There may be only one definite line of fracture, with bending or greenstick fractures in two other areas to produce a W-type configuration of the arch and a V-shaped cosmetic deformity. Occasionally, three definite lines of fracture producing two free segments occur. In this case, the normal convexity of the temporal area is lost. Flattening of the side of the face was noted in 57% of isolated zygomatic arch fractures in a study by Ellis et al.²⁶

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Accompanying zygomatic arch fractures may be trismus as a result of impingement of the fractured segment on the temporal muscle (see Fig. 16-38 A ). This finding was noted in 45% of 166 isolated zygomatic arch fractures by Ellis et al²⁶ and in 67% of those in Knight and North’s series.³⁵ The patient may have difficulty in shifting the mandible toward the injured side. An occasional yet interesting finding has also been some visual disturbances, such as diplopia, occurring early after injury and subconjunctival ecchymosis.^8,96

The necessity for treatment of these injuries is based on clinical detection of cosmetic or functional disturbances. In the study by Ellis et al,²⁶ 20% of zygomatic arch fractures were not treated. However, other studies have shown a variable ratio of treated versus nontreated zygomatic arch fractures.²⁰

Reduction of these fractures can be simply accomplished by any of the techniques already described for ZMC fractures. A percutaneous bone hook, the Gillies temporal approach, and an intraoral approach all are acceptable techniques. The need for stabilizing zygomatic arch fractures varies with the location of the injury, number of fractures, and displacement of the segments. Ellis et al²⁶ have found that 10 of 126 (7.3%) isolated zygomatic arch fractures treated in their study required fixation. Others have reported that almost every zygomatic arch fracture is stable, once elevated.^35,36,76

Stabilization of depressed zygomatic arch fractures has been achieved in a number of ingenious ways. Usually, the use of percutaneous circumferential wires or heavy sutures passed around the arch with an aneurysm needle or Mayo trocar and tied to an external object has served this purpose well (Fig. 16-39). Plastic oral airways,²¹³ metal eye shields,²¹⁴ short pieces of endotracheal tubing,²¹⁵ and orthopedic finger splints^216,217 all have been used as the external devices. The passing of an awl and tightening of wires in this region of the face may be expected to damage branches of the facial nerve but this complication has not been reported. Some have placed materials such as gauze and balloons between the zygomatic arch and lateral aspect of the mandible through an intraoral approach⁸¹ ; however, this approach is usually unnecessary.

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Occasionally, the zygomatic arch requires ORIF. Fractures that are in several segments or that are grossly displaced are candidates for this form of treatment. The zygomatic arch can be safely approached from a coronal incision. Once the arch has been identified by subperiosteal dissection, it can be manually repositioned and stabilized. Long, thin bone plates are used to maintain the normal arch morphology. When plates are used, one should be cognizant of the normal flat configuration of the zygomatic arch. Bone plate fixation that provides too much curvature to the arch results in a noticeable cosmetic deformity. Although the zygomatic arch is called an arch, in reality it is not all that curved.

Following reduction of zygomatic arch fractures, one must protect the side of the head from injury. The force of the weight of the head resting on a pillow is sufficient to displace even a properly reduced fracture. Many materials are available that can be taped to the side of the head to protect the zygomatic arch following reduction. Commonly used and readily available materials that can be formed and applied for this purpose are paper cups, metal eye patches, aluminum finger splints bent in a staple configuration,²¹⁸ and a number of others (Fig. 16-40). Ideally, they should be left in place for 2 to 3 weeks.

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continued

PART III Management of Head and Neck Injuries

PERIORBITAL INCISION PROBLEMS

Several complications can result from the incisions described earlier for approaching the infraorbital rim and orbital floor and walls. Minor complications, such as dehiscence, hematoma or seroma formation, and lymphedema, are more bothersome than difficult to handle. Hematomas and seromas, when large, can be decompressed with a needle and syringe. Lymphedema subsides with time, especially if the lower lid is supported in its proper position. Dehiscence of a wound may require nothing more than observation unless it is large, at which point wound care and resuturing may be necessary.

One problem that may accompany any incision to gain access to the infraorbital rim and internal orbit is a vertical shortening of the lower lid following healing (Fig. 16-41). This shortening probably occurs as a result of scarring between the tarsal plate and periosteum, shortening the orbital septum. To help prevent this, superior support of the lower lid for several days (or until gross edema has resolved) following surgery is beneficial. The most direct method of achieving this support is through the use of a Frost suture, in which a suture is placed through the dermal surface of the lower lid just inferior to the gray line and is taped to the forehead (Fig. 16-42).

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This technique closes the eye, supports the lower lid, aids in the dissipation of lid edema, and allows one to examine the globe and vision by simply removing the tape from the forehead and opening the eyelids.

Postsurgical deformities of the lower eyelid are distressing problems, although most cases are self-limited. Ectropion, or an outward curl to the lower eyelid, is classified as mild when there is only slight lifting of the lid from the globe. Moderate ectropion is associated with lifting of the lid from the globe and a shortening of the vertical height of the lower eyelid. Severe ectropion is a combination of shortening of the eyelid and true eversion of the eyelid, not just a lifting away. Mild and moderate ectropion usually resolve with the passage of time and with gentle massage of the lid. Severe ectropion may require surgical correction. Entropion, or an inward curl of the lower eyelid, occurs less commonly but is more distressing because of the irritation of the eyelashes on the globe. Entropion that does not resolve spontaneously may require surgical correction (Fig. 16-43).

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The incidence of ectropion or scleral show reported for subciliary incisions with skin and muscle dissection varies considerably.^{125,126,219-221} Heckler et al¹³⁰ have reported a 6% temporary incidence after a skin-muscle approach to the orbital floor. Manson et al and Dufresne et al^222-224 have noted a 10% incidence of temporary ectropion or scleral show using a skin-muscle flap to approach the orbit. They noted that with time, sufficient resolution occurred that patients did not request corrective surgery. Wray et al¹²⁶ have compared the incidence of ectropion following subciliary exposure of orbital fractures with the conjunctival approach and found an extremely high incidence of postoperative vertical lid shortening in the former. After subciliary incisions, ectropion developed in 19 of 45 eyelids, 15 of which were transient and 4 of which required operative intervention. A prospective study by Lacy and Pospisil²²⁵ has reported on 55 skin-muscle dissections through the eyelid to perform surgery for zygomatico-orbital trauma. Ectropion occurred in 18% of their cases, being transient in all but two. They again noted an increased incidence in older patients and in those with edematous lids during surgery. Bähr et al²²⁶ have confirmed that orbits operated on after the onset of traumatic edema develop more complications. They found that ectropion developed in 3 of 16 patients (18.8%) after a subciliary incision with skin-muscle dissection to approach the orbit. However, the ectropion was permanent in only one patient. Antonyshyn et al¹⁸¹ have found a scleral show frequency of 16.6% with this same approach. Appling et al²²⁷ have compared a subciliary incision with skin-muscle dissection with transconjunctival approaches to the orbit and noted a 12% rate of transient ectropion and a 28% rate of permanent scleral show after the subciliary approach. No transient ectropion and only a 3% incidence of permanent scleral show were found with the transconjunctival approach.

INFRAORBITAL NERVE DISORDERS

Occasionally, a patient who has had treatment of a zygomatic fracture will complain that the upper teeth, especially the anteriors, feel numb or different, and even painful to heat, cold, or light touch. De Man and Bax,⁵² in a study of 273 isolated ZMC fractures, found that 80% suffered from dysesthesia on admission. Nordgaard⁴⁹ found sensory disturbance in 96% of 100 patients immediately after fracture. Jungell and Lindqvist⁵¹ found that 81% of patients with ZMC fractures had paresthesia of the infraorbital nerve. The figure was even higher (94%) in those who required surgical treatment. Most patients had regeneration, but 42% of patients had some degree of persisting sensory disturbance. Only 12% of patients had total loss of sensation. Similar statistics have been reported by Altonen et al,²⁰ who observed that 42% of patients had some permanent changes and 10% had marked deficits. Zachariades et al²²⁸ have found that 27% of their patients have alteration of infraorbital sensation 6 months after ZMC fractures. Additionally, they found that inpatients who did not undergo surgery because of minimum or no displacement, all recovered sensation.

An interesting finding with nerve deficits after ZMC fractures has been that fewer deficits remain in patients treated with rigid fixation of their fractures. Champy et al,¹¹¹ de Man and Bax,⁵² Zingg et al,^87,88 and Taicher et al²²⁹ have stated that reduction and fixation are important factors in the recovery from sensory disturbances of

the infraorbital nerve. They maintain that fixation of the fracture line by a miniplate, mainly in the frontozygomatic area, achieves the fastest recovery rate of neurosensory dysfunction. The proposed method whereby recovery improves is that improved stability prevents continued compression on the nerve after reduction.

Tajima⁵³ has indicated that full recovery should occur within 5 months. Jungell and Lindqvist⁵¹ have found that most recovery occurs early, within the first 2 weeks. However, Lund²⁸ has noted sensory disturbances in almost 50% of patients more than 2 years after their injuries. In cases of persistent dysesthesia, anesthetization of the superior alveolar nerves by local infiltration should be attempted. If symptoms are not alleviated, the clinician should suspect a disruption of the infraorbital nerve within its canal where the middle and anterior superior alveolar nerves take origin, with possible neuroma formation. Surgical exploration may be necessary when the altered sensation is bothersome to the patient.

IMPLANT EXTRUSION, DISPLACEMENT, AND INFECTION

The possible risks that always exist when an alloplastic material is used are infection, displacement, and extrusion of the implant. Infection usually occurs early and may result in the need for implant removal. These complications are uncommon but do occasionally occur. Aaronowitz et al²³⁰ have reported a 3.9% early complication rate (within 1 month of surgery) when Teflon implants were used to reconstruct the orbital floor. These complications consisted of infections and improper placement of the implant, necessitating removal in all cases. They also found a 2.8% late complication rate, which included one patient with a cutaneous antral fistula. Correlation criteria were established to determine whether any preoperative or intraoperative findings correlated with the complication rate. The only positive correlation was an association between the concomitant use of antral packs and implants. Therefore, they recommended that this application be avoided. The association between antral packs and implants has also been noted by Spira.²³¹

Polley and Ringler²³² have reviewed 230 Teflon implants used on the orbital floor over a 20-year period and found only one postoperative infection that necessitated implant removal. There were no other complications. The implants were not routinely sutured to the orbital floor in their series. Similarly, Morrison et al¹⁹⁵ have reviewed 311 cases of silicone implants placed over a 20-year period and found that at least 13% required removal for one reason or another.

Particularly distressing are the occasional occurrences of acute foreign body reactions to silicone¹⁹¹ and Teflon¹⁹⁰ orbital floor implants many years after implantation. It may be that slight trauma to the implant precipitates this reaction, because one of the patients reported was subjected to a blow to the orbit that preceded the acute reaction. In these subjects, implant removal and at least partial removal of the inflammatory tissue allowed resolution of the process. Other series have shown complication rates ranging from 3% to 15% with the use of alloplasts other than Teflon.^233-238 When the implants become displaced or extruded, they should be removed (Fig. 16-44). It is usually not necessary to place another at the time of surgery; however, if enophthalmos or ptosis occurs, reconstruction of the internal orbit can be undertaken secondarily.

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PERSISTENT DIPLOPIA

Binocular diplopia present initially after zygomatic fracture is generally a result of edema or hematoma of one or more extraocular muscles or their nerves and intraorbital edema or hematoma. In these cases, resolution of diplopia following fracture treatment (if necessary) usually occurs spontaneously within 5 to 7 days.^49,239 Occasionally, muscle entrapment is the cause of diplopia but such entrapment should be apparent with the use of a forced duction test.

Persistent diplopia occurs in a small percentage of patients after what appears to be appropriate treatment, ranging from 3% to 15% in reported series. The cause of persistent diplopia is not known, but it has been thought to result from scar contracture and adhesions in ocular muscles or between them and other structures.

Neural injuries from the trauma or from surgery may also produce persistent diplopia. It should be pointed out that few of these patients complain of their diplopia, and blurring of vision may be found only in upward and lateral gaze. If the diplopia is bothersome, the patient should be referred to an ophthalmologist for evaluation and possible treatment with exercises and/or surgery.

ENOPHTHALMOS

Enophthalmos may be present, even after what appeared to be proper treatment at the time of the operation. Few patients are aware of enophthalmos and it therefore seldom presents a clinical problem unless severe. The incidence of enophthalmos varies considerably from one report to the next, depending on how much globe retrusion is considered to represent enophthalmos. The usual figure is low, reported between 5% and 12%.^27,29,64 However, Altonen et al²⁰ have noted enophthalmos in 41% of patients. The reason for this high incidence probably stems from the 26% incidence of slight enophthalmos in their series. If one takes away the 26% who had slight enophthalmos, the figure becomes a more understandable 15%. In a comprehensive study of patients treated for complex orbital fractures, Antonyshyn et al¹⁸¹ have noted moderate enophthalmos, characterized by more than 3 mm of difference in projection from the uninjured globe, in 3 of 49 patients, and severe enophthalmos (more than 4 mm of difference) in 4 patients. Thus, 14% of their complex orbital injuries had some degree of enophthalmos.

Enophthalmos has been thought to be caused by a decrease in volume of the orbital contents, increase in volume of the bony orbit, loss of ligament support, scar contracture, or combination of these. The most popular theories of the mechanism of enophthalmos have been bony orbit enlargement and fat atrophy. A study by Manson et al,⁶⁷ which evaluated patients demonstrating post-traumatic enophthalmos using quantitative CT, found that an increase in bony orbital volume was present in these cases. Others have demonstrated similar findings.^66,240 The study by Manson et al, however, did not find loss of soft tissue volume within the orbit, which could signify fat atrophy. It is probably unusual to have great losses of orbital soft tissue volume unless infection has occurred, producing post-traumatic fibrosis and atrophy of the periorbital fat. Thus, post-traumatic enophthalmos is usually caused by an increase in bony orbital volume (Fig. 16-45; see also Fig. 16-14). Even after restoration of the orbital rims and floor at the time of surgery, defects located posteriorly along the medial and/or lateral walls are common and frequently overlooked, and are probably the main reason for postoperative enophthalmos.^63,241,242

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Enophthalmos is difficult to correct secondarily; however, improvement is possible. The goal of surgery is to reduce orbital volume by reconstructing the internal orbit and, if necessary, placing a space-occupying material behind the globe, thus displacing the globe anteriorly (see Fig. 16-45). A space-occupying material placed in front of the globe worsens the enophthalmos and that placed along the axis of the globe only shifts the globe to the opposite side.

Several materials have been used to decrease orbital volume, such as glass beads,^243-245 silicone sheets or sponges,^246-249 Teflon beads,²⁵⁰ cartilage grafts,^251-253 porous polyethylene sheets,¹⁸⁵ hydroxylapatite,^254,255 and metallic mesh or plates.^203,205 The advantage of using nonresorbing materials is that they maintain their bulk within the orbit; however, extrusion, migration, and infection are always possible. The implant or bone may need to be placed in several locations within the orbit to affect the anterior projection of the globe; therefore, access to almost the entire circumference of the orbit is often necessary. Usually, the orbital floor, medial wall, or posterolateral wall of the orbit requires an implant or graft posterior to the axis of the globe.¹³¹

BLINDNESS

Reduced vision and blindness have occasionally been reported after the treatment of zygomatic fractures. Ord²⁵⁶ has reported that the incidence of postoperative retrobulbar hemorrhage and blindness following treatment of zygomatic fractures is 0.3%. Blindness has also been reported in patients following internal orbital reconstruction.^186,257-261 These complications are extremely rare occurrences, but they have devastating consequences.

There are several causes of reduced vision following trauma or fracture repair. Direct damage to the optic nerve from displacement of a fracture segment or from a fractured optic canal is rare but possible.^4,262-265 Postmortem investigations, however, have demonstrated that injury to the optic nerve resulting from optic canal fractures is rarely the result of osseous compression, laceration of the nerve, or hemorrhage into the nerve itself. More often, hemorrhage into the optic sheath or contusion of the nerve results in edema and compression.^266,267 The injury may lead to secondary compression of the vascular supply to the nerve where the nerve sheath is fixed to its bony surroundings. Another cause of blindness following zygomatic fracture or fracture repair is retrobulbar hemorrhage.

A major question that must be answered when blindness follows fracture repair is to determine what caused the blindness—the trauma or the surgery. The answer is important from a surgical standpoint and obviously of interest from a medicolegal standpoint. Unfortunately, one cannot always know the answer. If the patient was blind before surgery, the answer is obvious. However, most cases of blindness associated with zygomatic fractures have followed surgical intervention. It might therefore be concluded that blindness occurring after surgical intervention, which was not present before, is a result of the surgery. However, there have been reports in which blindness occurred days following injury, even when no surgery had been performed.^268,269 Spontaneous retrobulbar hemorrhage has also been noted following fracture but before fracture repair.^270,271 Thus, if the fracture had been treated, it might have been thought to be responsible for the blindness. Unfortunately, there is no ideal method of sorting out these problems.

RETROBULBAR AND INTRAORBITAL HEMORRHAGE

Intraorbital and retrobulbar hemorrhage can occur from the traumatic event or the surgery to repair the fractured zygoma. Reduced vision and blindness resulting from orbital hemorrhage have been reported in several cases of zygomatic fracture and fracture repair.* The cause of the reduced vision and blindness in these cases is unclear, but many have thought that these complications were a result of retinal artery occlusion. The occlusion of the retinal artery may be secondary to direct compression of the artery, sufficient stretching until the artery goes into spasm, or both. One explanation for the mechanism whereby stretching of the retinal artery is possible is that when hemorrhage into or around the muscle cone occurs, the eye protrudes. Because the muscles are fixed posteriorly to the tendinous ring, they are stretched along with the nerves and vessels of the globe. Another explanation for the reduced vision has been offered by Hayreh,²⁷⁸ who postulated that increased intraocular pressure reduces the perfusion of the anterior head of the optic nerve in a progressive manner. Whatever the mechanism, the increase in intraorbital pressure from hemorrhage causes changes that can lead to blindness if not halted.

The signs and symptoms of retrobulbar hematoma include a tense proptosis (exophthalmos), periorbital swelling that may be in the process of increasing in size, retroorbital pain, dilation of the pupil, and ophthalmoplegia. Hueston and Heinze²⁷⁹ have stated that “retrobulbar hemorrhage is not an emergency, total blindness is.” If the process becomes static at this point, and if vision and retinal circulation are maintained, observation is indicated.^256,280 Fortunately, the vast majority of retrobulbar and intraorbital hemorrhages do not progress to produce visual impairment^281,282 and, when they do, most produce only transient and/or partial loss of vision.²⁸³ Most ophthalmologists do not treat retrobulbar hemorrhages or treat them conservatively with the application of ice, sedatives, bed rest, and/or diuretics, such as intravenous mannitol. Observation for signs of visual impairment, however, is warranted. Gradual absorption of the hemorrhage occurs and full range of motion usually returns in several weeks but cases have been reported in which blindness occurred days after surgery because of the development of the hematoma.^186,276 When the point is reached that the optic nerve or retinal artery becomes involved, the pupil becomes fixed and nonreactive to light. Funduscopic examination may reveal a pale edematous fundus, with blurring of the disc margins. The classic sign of arterial occlusion or spasm, the macula appearing as a bright red (cherry red) spot, is infrequently observed in reported cases.²⁸⁴ These findings, associated with visual loss, constitute and should be considered a medical emergency because permanent loss of vision will occur in several minutes if the orbit is not immediately decompressed. Hueston and Heinze²⁷⁹ have claimed that survival of the optic nerve head is at stake in this situation and 60 minutes of ischemia appears to

• References 6, 256, 265, 270, and 272-277.

be the limit for survival and recovery, although Rowe³³ has indicated that 15 to 20 minutes is a more accurate figure.

An ophthalmologist should be summoned immediately while orbital decompression is instituted. If one has placed an antral pack, this should be immediately removed. Orbital decompression can then be performed by a variety of approaches. If a transantral approach to reduce or fix the fractured zygoma has already been used, this approach can be used to decompress the orbit. The orbital floor should be carefully but quickly removed and the periorbita incised if it has not already been disrupted. This incision should provide an avenue for the escape of accumulated blood and cause an immediate increase in orbital volume. Careful and gentle suctioning by means of thin polyethylene tubing inserted into the periorbital tissue may also find pockets of hemorrhage.

If one has made an incision at the infraorbital rim for fracture reduction, it should immediately be reopened. If no blood is encountered below the periorbita, the periorbita should be incised if it has not already been lacerated from the injury, and blood should be evacuated. Careful blunt dissection through the periorbital tissue and dissection through the muscular septum between the lateral and inferior rectus muscles allows the intramuscular cone to be drained. Aspiration with a short piece of polyethylene tubing may help find areas of sequestered blood.³³

If no periorbital incisions were made during fracture reduction and/or fixation, a 2-cm inferior lid incision should immediately be made. In contrast to the usual approach to the infraorbital rim, however, incision through the orbital septum is desirable when one is surgically decompressing the orbit. Blunt scissors should be inserted within the wound along the inferior aspect of the orbital floor and spread to evacuate accumulated blood. Dissection into the muscular cone, as just described, may also be necessary.

If any of these measures are not successful, as indicated by the expulsion of fresh hemorrhage and the beginning of relief of proptosis, access to the superolateral aspect of the orbit should be provided. This can be rapidly and safely achieved via an eyebrow approach with dissection through the periorbita.^285,286 Decompression via a lateral canthotomy and small curvilinear incisions above and below the lateral canthus have also been advocated.^186,287

Decompression of the globe by perforating the anterior chamber of the eye has been suggested to be an effective treatment for managing retrobulbar hemorrhage^249,288 ; however, many surgeons doubt its effectiveness.^280,281 In any case, it is not recommended as an emergency measure by nonophthalmologists.

Other measures that should be used in conjunction with the aforementioned are the following: control of the systemic blood pressure, if high; bed rest; possible use of diuretics (e.g., IV mannitol, 200 mL of a 20% solution; 500 mg of acetazolamide [Diamox] IV); and high doses of systemic steroids (e.g., dexamethasone, 3 mg/kg initially and then 2 mg/kg every 6 hours). Ophthalmologic follow-up is mandatory.

MALUNION OF THE ZYGOMA

Malunion of the zygoma can be the result of improper reduction, improper fixation, or nonintervention when surgery was indicated. The last situation happens occasionally when the patient’s medical condition precludes early operative intervention, treatment is not sought by the patient, or the patient declines surgery until later. The signs and symptoms are the same as those seen in a patient with a fresh zygomatic fracture, including flattening of the malar prominence, enophthalmos, altered pupillary level, and limitation of mandibular motion.

When confronted with this problem, one has two treatment alternatives—camouflaging the defect with an implant or transplant or repositioning the malpositioned bone. The advantages and disadvantages of a malar implant or transplant and osteotomy should be understood. In cases of malunion, when minor deformity is present and limited to flattening of the malar eminence, with little orbital involvement, a subperiosteal implant or transplant can be inserted to restore normal facial form. Another situation in which an implant or transplant is useful is when the zygoma is so comminuted that it cannot be mobilized and repositioned in one piece. Many implant or transplant techniques and materials are available for this purpose. There are advantages and disadvantages to the use of any material, and several have been used for malar augmentation. Bone has been less frequently used than alloplastics because of the difficulty in contouring bone and the unpredictable amounts of resorption that may occur. Most surgeons use silicone or porous polyethylene implants in a subperiosteal location. The implant techniques described are beyond the scope of this chapter. If necessary, a coronoidectomy can be performed, along with implantation to improve the range of mandibular motion.

When concomitant functional deficits are present along with cosmetic deformity, zygomatic osteotomy should be considered because it will correct both problems simultaneously. If zygomatic refracture or osteotomy is selected as the appropriate treatment modality, preoperative CT is warranted. The areas of fracture, position of the globe, orbital volume and shape, and defects in the orbital floor or walls should be thoroughly investigated. Restoring a severely malpositioned zygoma to its proper position following malunion and simultaneously correcting existing orbital defects is a difficult and challenging undertaking. The ZMC must usually be refractured or, more appropriately, osteotomized to allow repositioning. Fixation is always necessary, and restoration of normal globe position may require internal orbital reconstruction of the bony orbit. Several techniques for zygomatic osteotomy have been used in the past and all can produce good results with proper attention to detail. However, preoperative planning and intraoperative repositioning are the most important steps. Software for computer planning and intraoperative navigation have greatly improved outcomes for such malunions.

Various soft tissue access incisions allow visualization of the osseous anatomy for osteotomy. Some surgeons refracture the ZMC using standard incisions, such as the eyebrow, inferior lid, and intraoral. Another approach that greatly facilitates zygomatic osteotomy is the coronal approach used in conjunction with subciliary and intraoral approaches (see earlier, “Coronal Approach”). With this approach, the zygoma can be totally freed from all external soft tissue attachments, facilitating osteotomy and repositioning. Although there may be concern that the zygoma will resorb or become infected after extensive stripping of soft tissue, this is a rare occurrence in craniofacial surgery, in which large segments of osseous tissue are completely stripped from their soft tissue attachments and replanted.²⁸⁹ If the old fracture site is visible, it can be used as the line of osteotomy. However, the fracture along the orbital floor should be used only if it does not extend too far posteriorly toward the orbital apex. A sharp osteotome, thin bur, or saw can be used to perform the necessary bony incisions. Care is taken to protect the infraorbital neurovascular bundle within its groove along the orbital floor and at its exit from the infraorbital foramen on the anterior surface of the maxilla. Care is also taken to protect the orbital contents.

The most difficult osteotomy to make is that extending from the inferior orbital fissure, along the temporal surface of the maxilla to the zygomatic buttress area of the maxilla. This osteotomy is greatly facilitated by the use of the hemicoronal flap, which permits access to this difficult area. A sharp osteotome can be easily inserted from the temporal approach into the inferior orbital fissure and can be used to create a fracture down the infratemporal aspect of the maxilla. The osteotomy along the anterior maxillary wall can be extended inferolaterally until it meets the posterior osteotomy at the zygomatic buttress of the maxilla. Some also use an intraoral approach in the maxillary vestibule to help complete this osteotomy. This is a helpful optional incision because it may be necessary to place bone grafts into the zygomatic buttress area, especially if nonrigid forms of fixation are applied along the orbital rims. Before mobilization, the zygomatic osteotomies should be carefully checked to verify that all osseous incisions have been completed. If mobilization is attempted while some bony areas are still intact, aberrant fractures may occur.

After the zygoma has been mobilized, it is repositioned. If the malunion was long-standing, it may be necessary to excise bone in some areas in which callus and new bone have formed to permit proper reduction. The lateral orbital rim may need to have some bone subtracted for proper repositioning; however, this is not always the case. The most accurate method of repositioning involves the use of intraoperative navigation to help the surgeon place the zygoma into the most symmetrical location, as determined by preoperative computer planning. The zygoma is best stabilized with bone plates at the frontozygomatic and possibly infraorbital areas. If necessary, bone grafts are inserted into bony voids (Fig. 16-46). The internal orbit is reconstructed as described earlier, with care being taken to correct defects in the lateral wall of the orbit. When the zygoma has been comminuted by trauma, it may be necessary to onlay graft or implant over the malar prominence to reestablish normal contour. The zygomatic arch can be reconstructed with a strip of cranial bone or rib.

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Graft

PART III Management of Head and Neck Injuries