Fig. 6.1
Zygomaticoorbital fracture: (a) Isolation of the zygomatic bone with respect to four sutures. (b) Fracture lines in a typical zygomaticoorbital fracture: (1) the fracture line starting from the inferior orbital fissure and propagating upward along the sphenozygomatic suture to the frontozygomatic suture where it crosses the lateral orbital rim; (2) the fracture propagating from the inferior orbital fissure anteriorly along the orbital surface of the maxilla; it crosses the infraorbital rim and propagates downward along the anterior surface of the maxilla under the zygomaticomaxillary suture; (3) the fracture beginning at the inferior orbital fissure, running downward along the inferotemporal surface of the maxilla and continuing anteriorly under the zygomaticomaxillary suture until it merges with fracture no. 2; and (4) one or several fracture lines of the zygomatic arch fracture. (c) Spread of the frontozygomatic suture. (d) Orbital rim fracture
Hence, it must be acknowledged that the term zygomatic bone fracture fails to provide the essence of the patient’s trauma. The term zygomaticoorbital fracture appears more apt as it determines the key role played by the zygomatic bone in the formation of the orbital floor and the lateral orbital wall. Neither the normal orbital anatomy nor the original facial configuration can be recovered without meticulous repositioning of the zygomatic bone [1].
6.2 Epidemiology
Fractures of the zygomaticoorbital complex rank third in incidence among all bone injuries occurring in humans. The share of zygomaticoorbital fractures in children and adolescents is 60 % of all facial fractures; in adults, this figure is 24–33 %, with only mandibular fractures being more frequent (70 %) [2–5]. In 40 % of cases, the fractures affecting the zygomatic bone are accompanied by injuries to the maxilla, orbit, and nose as well as limb traumas [6–8]. Twenty-five percent of the patients have head injuries. As a result, zygomaticoorbital fractures are the most frequent reason for admission to trauma units [9, 10].
These types of fractures typically occur in individuals aged 21–40 years and are 3–4 times more frequently observed in males than in females [8]. The main causes of these injuries include car accidents (45–80 %), violence (20 %), falls (20 %), and sport activities (13–20 %) [11–13].
Unilateral fractures of the zygomaticoorbital complex are the vast majority; bilateral fractures are observed only in 5 % of patients. Despite the fact that the incidence of concomitant injuries of the visual system (traumatic optic neuropathy, incomitant or restrictive strabismus) is as high as 33–36 % [14–18], very few publications have been devoted to zygomaticoorbital fractures [19].
6.3 Mechanisms of Fracture Development
An impact of a sufficiently high-energy object that moves from the anterolateral in the posteromedial direction causes isolation of the zygomatic bone with respect to the four sutures, the superior (frontozygomatic), the medial (zygomaticomaxillary), the lateral (zygomaticotemporal), and the posterior (sphenozygomatic) (Fig. 6.1a) [20]. Dislocation of the isolated zygomatic bone usually additionally causes a fracture of the orbital floor and the anterior wall of the maxillary sinus (Fig. 6.1b). In the English-language literature, this condition is known as a tetrapod (quadripod) fracture [21, 22].
A rather frequent isolation of the zygomatic bone with respect to three sutures (the frontozygomatic, zygomaticomaxillary, and zygomaticotemporal ones) is known in the English-language literature as a tripod fracture [23] or a zygomaticomaxillary fracture although a more accurate term would be “quadripod” as usually all four zygomatic sutures are usually involved.
6.4 Fracture Classification
The low-energy fractures comprising 18 % of all zygomaticoorbital injuries are characterized by at least one incomplete fracture, most often, that of the frontozygomatic suture. No surgical management is required as bone fragments are either not displaced or displaced negligibly [24].
Moderate-energy complete zygomaticoorbital fractures comprise (77 %) of the fractures and are characterized by mild to moderate dislocation with respect to all the sutures and by disintegration of the fracture edges. The dislocation orientation (inferior, medial, posterior) depends on the applied force vector.
High-energy zygomaticoorbital fractures are usually components of the Le Fort or panfacial fractures. They can rarely be observed as an isolated entity (5 %).
6.5 Diagnosis of the Zygomaticoorbital Fracture
Since these patients are usually admitted to the hospital because of multiple trauma, it is necessary to include meticulous analysis of the vital signs, evaluation of the neurological status, and the condition of the thoracic and abdominal organs and extremities.
The clinical presentation of the fracture depends on the degree to which the zygomaticoorbital complex has been affected.
As mentioned previously, either the absence or minimal dislocation of bone fragments is typical of low-energy incomplete fractures [24]. As a result, the clinical presentation is limited to periorbital ecchymosis (over 70 % of cases), soft tissue edema (over 20 % of cases), and subconjunctival hemorrhage (~40 %) [25].
Moderate-energy complete zygomaticoorbital fractures (77 %) are the comminuted fractures and are accompanied by either mild or moderate dislocation with respect to all the sutures. The isolation of the zygomaticoorbital complex starts in the area of the zygomaticomaxillary suture and the infraorbital rim; the frontal process (the frontozygomatic suture), greater wing of the sphenoid (the sphenozygomatic suture), and the zygomatic arch (the zygomaticotemporal suture) are affected in more severe cases (Fig. 6.2) [24].
Fig. 6.2
Types of injuries of the zygomaticoorbital complex (according to the CT data): (a) The minimal diastasis of the zygomaticomaxillary junction (an arrow). (b, c) 3D reconstruction of a moderate-energy fracture with spread of the zygomaticomaxillary suture and the infraorbital rim (arrows). The minimal spread of the frontozygomatic suture is clearly observed (b). (d) Diastasis of the sphenozygomatic suture and formation of a comminuted fracture of the lateral orbital wall (an arrow). (e, f) A profound dislocation of the zygomatic bone and its separation at all the sutures, including the zygomaticotemporal one (arrow), which are clearly seen both in an axial CT scan (e) and in 3D reconstruction
The clinical presentation depends on the number of facial bones destroyed at the moment of injury (Fig. 6.9). Diagnosis is facilitated by the fact that each fracture type has its own typical complex of symptoms.
Signs of destruction of the zygomaticomaxillary suture include edema of facial soft tissues, sensation disorders in the area of the superior dental plexus, local palpation tenderness of the superior gingivobuccal fold, and deformation of the zygomaticoalveolar crest (Fig. 6.3).
Fig. 6.3
Symptomatology of zygomaticoorbital fractures: (a) A typical moderate-energy fracture. (b) Typical antero-postero-inferior displacement of the zygomatic bone illustrated by a test with a ruler placed to the zygomatic arch and squama temporalis. Divergence of the ruler from the vertical position is indicative of displacement of the zygomatic bone. (c) Ipsilateral retraction of the zygomatic region and tenderness of buccal soft tissues. (d, e) “Bone step” symptom revealed by palpating the zygomaticoalveolar crest (d) and the infraorbital rim (e). (f) Appearance of a patient with a low-energy injury (ecchymosis and subconjuctival hemorrhage with the facial width and contour of the zygomatic region remaining intact and proper position of the lateral angle of the orbital fissure). (g–i) Facial changes typical of the moderate- and high-energy fractures. Prolapse of the lateral canthus, evident hypoglobus (h, i), and enophthalmos indicated by deepening of the upper eyelid groove (i). (j, k) Less evident but much more frequent aesthetic disorders (With the permission of professor G.A. Khatskevich and associate professor M.M. Solovyev)
The hematoma typical of zygomatic fractures, the “raccoon eye,” develops at the moment of trauma and is caused by vessel injury in the fractured area and spreads beyond the orbicularis oculi muscle. The “raccoon eyes” appearance observed in patients with basilar skull fracture occurs late, showing several hours or sometimes the next day after trauma, and never spreads beyond the orbicularis oculi muscle.1
If an injury of the anterior wall of the maxillary sinus is complicated by rupture of the mucous membrane, moderate bleeding from the ipsilateral half nose is observed. Because of the fracture of the sinus wall and blood in the sinus, percussion of premolars generates a dull sound (the cracked pot symptom according to E.S. Malevich) on the side of injury.
Rare manifestations of the zygomaticoorbital fracture include orbital emphysema [26] and propagation of subcutaneous emphysema to the retropharyngeal space and the mediastinum. This rare finding may mislead a physician into searching for a nonexistent damage to the esophagus and other mediastinal structures [27, 28].
Along with chemosis, subconjunctival hemorrhage, periorbital edema, and “raccoon eyes” hematoma, the fracture of the infraorbital rim can be diagnosed by the easily palpated “bone step” in the middle third of the infraorbital rim (Fig. 6.3e) and dysesthesia in the distribution of the infraorbital nerve.2
In the acute aftermath of trauma, neuropathy is typically observed in 70–80 % of patients. Its incidence depends on the type of damage to the zygomaticoorbital complex. The following situations are associated with the highest risk for developing neuropathy: the fracture crosses the infraorbital canal, a comminuted type of fracture, and displacement of bone fragments which usually accompany moderate- and high-energy fractures of the zygomatic bone [29].
The main mechanisms contributing to the development of traumatic neuropathy include compression of the infraorbital nerve in the infraorbital canal; perineural edema or hematoma; and less frequently, ischemia and nerve rupture [30].
The infraorbital nerve is completely anesthetized only if its trunk is anatomically interrupted, which is an extremely rare event. The patients most often have (in order of decreasing incidence) hypoesthesia, paresthesia, and hyperesthesia. Since Aβ myelinated fibers responsible for pressure and touch are more sensitive to compression and ischemia than Aδ myelinated and C unmyelinated fibers (heat and pain sensitivity), the patients may have mosaic neurosensory deficit [31].
Fracture of the infraorbital rim inevitably involves the orbital floor during the traumatic process. However, the orbital floor fracture as a component of the zygomaticoorbital fracture is significantly different from its isolated blowout fracture in terms of incidence (75 and 25 %, respectively) [25], clinical presentation, and treatment strategy (Fig. 6.4a–c).
Fig. 6.4
Types of injuries of the orbital floor in patients with a zygomaticoorbital fracture (arrows): (a, b) A small linear-type defect without soft tissue entrapment (hence, without diplopia) accompanied by the minimal increase in orbital volume (b). (c) A “saucer-like” fracture causing a significant increase in the orbital volume and enophthalmos. (d, e) Spread of the sphenozygomatic suture. (f) Total orbital floor fracture caused by rotation of the zygomatic bone
In patients with a blowout fracture of the orbital floor, the probability of detecting another facial fracture is less than 4 %, while the converse is true with the facial skeleton when almost always there is a combined with injury of the orbital floor and rim. Because motor vehicle accidents are the most frequent causes of this type of trauma, these patients also have a sevenfold higher risk of concomitant trauma to the body and limbs.
Periorbital edema and hematoma in patients with zygomaticoorbital fractures occur 2.5 times more often as compared to those caused by isolated injury of the orbital floor, while diplopia and oculomotor disorders are twofold less common (i.e., in 30–35 % of cases) [25].
If diplopia is caused by edema or hematoma of the inferior muscle complex or contusion of the inferior branch of the oculomotor nerve, one can expect spontaneous regression of diplopia within 3–6 months. However, the more frequent reasons for diplopia in patients with zygomaticoorbital fractures include entrapment of the muscle or adipose tissue in the fractured area. The vertical traction test is used to make this diagnosis.
In patients with concomitant diastasis of the frontozygomatic suture, the physical examination will reveal a depression when palpating the upper half of the lateral orbital rim. This finding demonstrates that the zygomatic bone has been profoundly dislocated.
Spread of the sphenozygomatic suture, which is almost identical to the diagnosis “lateral orbital wall fracture,” plays a significant role in pathogenesis of functional and aesthetic problems. However, there is a paucity of literature on this type of fracture. The diastasis of the sphenozygomatic junction indicating that the zygomatic bone has rotated around its vertical axis results in a significant increase of the orbital volume, which leads to significant enophthalmos and hypoglobus (Fig. 6.4d–f) [32]. It is the zygomaticoorbital rather than the isolated blowout fracture that is the main reason of late enophthalmos [6, 25, 33].
As for the immediate post-traumatic period, exophthalmos is usually observed in patients due to edema of the orbital tissues, while the enophthalmos appears not earlier than 2 weeks after the trauma. Early enophthalmos indicates that the zygomaticoorbital complex has been severely damaged and requires urgent surgical intervention.
When evaluating the eyeball position in patients with zygomaticoorbital fractures, one should bear in mind that the Hertel exophthalmometer cannot be used because its point of fixation, the lateral orbital rim, has been destroyed or has been profoundly dislocated (Fig. 6.5a) [4, 34, 35]. The Naugle orbitometer (Fig. 6.5b) that uses the frontal arch and the malar eminence as points of fixation and the infraorbital rim as the reference point has been used for this purpose in clinical practice since 1992.
Fig. 6.5
Hertel exophthalmometer (a) and Naugle orbitometer (b)
Sometimes the zygomatic bone is rotated inward, into the orbit, thus forming the pattern of the blow-in fracture of the lateral wall (Fig. 6.6) [36, 37].
Fig. 6.6
Pattern of the blow-in fracture (arrows) of the zygomatic bone: (a–c) Dislocation of the lateral orbital wall secondary to the zygomatic bone pushed into orbital cavity. (d) Incorporation of a fragment of the greater wing of the sphenoid bone to the muscle cone. (e) Fracture of the trigone, i.e., the central third of the greater wing of the sphenoid bone near the sphenosquamosal suture indicating that the fracture is high-energy one
The first thing to do when examining these patients is to rule out any damage to the eyeball by a bone fragment (observed in 10 % of patients) and traumatic optic neuropathy (6 %) [18, 38–40].
The main mechanism of neuropathy is nerve compression in the so-called deep orbit by disturbed microcirculation in the minor pial vessels of the optic nerve leading to retrobulbar or optic nerve sheath hematoma [41–43]. The nerve can be compressed in the optic canal and also the development of the superior orbital fissure syndrome if the nerve is directly impacted by bone fragments [41, 44]. Furthermore, since the optic nerve dural tissue and the periosteum are continuous near the point where the nerve enters the optic canal, abrupt deceleration (e.g., in a frontal crash) may cause its avulsion.
Incorporation of a fragment of the frontal process of the zygomatic bone and/or the greater wing of the sphenoid into the muscular cone is highly likely to lead to permanent or intermittent compression of the optic nerve (Fig. 6.6d) [37, 44–46]. In the latter case, a patient has a typical symptom of sudden gaze-evoked amaurosis [47, 48]. Vision quickly recovers after the gaze returns to its primary position. Despite the intraconal type of injury, exophthalmos may be absent in this situation. However, ophthalmoscopic imaging always reveals changes in the optic disc or choroidal folds.
The degree of neuropathy varies over a broad range from mildly decreased color perception to full loss of vision. Instantaneous and total blindness is indicative of optic nerve avulsion or stroke and is an unfavorable prognostic factor [37]. Delayed onset and gradual or incomplete vision loss are typical of optic nerve compression and bring hope that it will be restored to some extent [49].
A zygomatic arch fracture is accompanied by flattening of the zygomatic area, facial widening, and disruption of the zygomatic arch at a point where the force was applied (the “depression” symptom). In a case of conventional inward and downward dislocation of fragments, additional signs include significant restriction in opening the mouth and impeded lateral movements of the mandible on the affected side. These restrictions of movement occur because of entrapment of the coronoid process of the mandible by a dislocated fragment of the zygomatic arch (Fig. 6.7c–e) [50]. A certain degree of trismus is typical of zygomatic arch fractures because of indirect injury of the muscle of mastication and damage to its attachment site.
Fig. 6.7
Entrapment of the coronoid process of the mandible by a dislocated zygomatic bone fragment: (a–b) the entrapment mechanism for a zygomaticoorbital fracture (a) and fracture of the zygomatic arch (b). (c) 3D reconstruction of a zygomatic arch fracture (shown with an arrow). (d, e) Axial CT scan of a zygomatic arch fracture with fragment displacement (shown with an arrow)
High-energy fractures of the zygomatic bone. In addition to the aforementioned injuries of the zygomaticoorbital complex, high-energy fractures also involve comminuted fractures of the greater wing of the sphenoid, zygomatic arch, and the external angular process of the frontal bone. These fractures affect the glenoid fossa and cause the profound posterolateral dislocation of the zygomatic arch and the malar eminence. They result in such typical signs as flattening of the zygomatic region, facial widening, and enophthalmos because of the increased orbital volume.
Thus, the full-scale clinical presentation of a classical zygomaticoorbital fracture with profound fragment dislocation includes:
Facial widening, flattening of the zygomatic area, inferior position of the lateral angle of the palpebral fissure, subconjunctival hemorrhage, and periorbital ecchymosis
Dysesthesia along the infraorbital nerve
The “bone step” symptom observed when palpating the upper half of the lateral and middle thirds of the infraorbital rim and the zygomaticoalveolar crest
Emphysema of the orbit and facial tissues
Trismus
It should be mentioned that rapidly developing edema in patients with facial injuries often disguises the typical symptoms of a zygomaticoorbital fracture. In this case, radiological methods are the best choice for accurate diagnosis.
6.6 Radiological Diagnosis
The radiological signs of zygomaticoorbital fractures are most clearly visualized on images in semiaxial view. These signs include diastasis and deformation of the contours of the frontozygomatic suture, steplike deformation or discontinuity of the infraorbital rim contour near the steplike deformation, disturbed configuration of the zygomaticoalveolar crest, asymmetry of orbital openings, ipsilateral thickening and compaction of facial soft tissues, blood in the sinus, and emphysema.
Despite clear visualization of the zygomaticoorbital fracture, radiology does not provide comprehensive information on the length and degree to which the fragments have been displaced in all three planes. That is why radiological examination is currently used only as a screening method [51]. Axial, coronal, and oblique sagittal CT scanning are needed to make a radiological diagnosis of a zygomaticoorbital fracture [52–54].
When analyzing the axial CT scans with cross sections 1.5 mm thick, the main focus is placed on the condition of the lateral orbital wall. In patients with typical zygomaticoorbital fractures, this wall is separated into two fragments along the sphenozygomatic suture: the zygomatic bone and the greater wing of the sphenoid (Fig. 6.8b, c). The condition of the zygomatic arch and zygomaticomaxillary suture are evaluated in the same view (Fig. 6.8d). The coronal and oblique parasagittal views are the optimal ones to analyze the degree of damage to the frontozygomatic suture and the infraorbital rim, respectively (Fig. 6.8e, f).
Fig. 6.8
Radiological diagnosis of a zygomaticoorbital fracture (the fracture line is shown with arrows) (a) Fracture of the zygomatic bone. (b) An axial CT scan that illustrates the spread of the sphenozygomatic suture. (c) CT presentation of diastasis of the sphenozygomatic suture combined with fracture of the greater wing of the sphenoid bone. (d) Destruction of the zygomaticomaxillary suture seen in an axial CT scan. (e) Spread of the frontozygomatic suture in an coronal CT scan. (f) Sagittal CT scanning allows one to detect a fracture of the infraorbital rim and the anterior wall of the maxillary sinus
6.7 Management of Zygomaticoorbital Fractures
No surgical treatment is needed for zygomatic bone fractures with no or with minimal bone fragment dislocation. In approximately 40 % of patients with zygomatic fractures, conservative management is sufficient with close follow-up for 3–4 weeks post trauma to evaluate the healing of the fracture [7, 57–61].
However, zygomaticoorbital fractures with bone fragment dislocation accompanied by functional and/or aesthetic disorders need surgical management. Usually this involves a joint effort of maxillofacial and plastic surgeons together with an ophthalmologist.
Time period for surgery. Taking into account the high rate of osteogenesis in patients with maxillofacial injuries [62], the optimal choice is to perform an intervention in the acute trauma period, i.e., within the first 14 days [63, 64]. If the surgical repair is delayed, there is a worse functional and aesthetic result because the repair usually requires osteotomy, distraction osteogenesis, facial contouring surgery, and sculpturing the cicatricial soft tissues [1, 65].
The surgical success relies on meticulous repositioning of the zygomaticoorbital complex. This requires complete exposure of the entire fracture site and apposition of the bone fragments using titanium supports 3 [4, 54, 67–69]. The number of open reposition and rigid fixation areas depends on the severity of a zygomaticoorbital fracture [70]. Titanium plates are placed with allowance for the positions of facial counterforces (Fig. 6.9).
Fig. 6.9
Facial counterforces
Surgical approaches to the zygomaticoorbital fracture. Various combinations of the upper gingivobuccal as well as periorbital and coronal approaches are used to expose the zygomaticoorbital complex.
An upper gingivobuccal incision using the procedure proposed by Keen visualizes the zygomaticomaxillary suture very well (Fig. 5.4d) [71].
The intraoral approach is usually supplemented with one of the numerous incisions of the lower eyelid allowing one to reach the infraorbital rim. The preseptal transconjunctival approach combined with lateral canthotomy is preferred (Fig. 3.23).
Dingman described approaching the fracture through the lateral portion of the eyebrow and this approach is typically used to expose the frontozygomatic suture. Since this approach is often complicated with severe cicatrization, an approach continuing the supratarsal fold outward has been proposed [72, 73]. Another alternative is to continue the subciliary or the transconjunctival incision of the lower eyelid laterally. The so-called extended C-shaped conjunctival approach allows one to reach the frontozygomatic suture, the lateral wall, the infraorbital rim, and the zygomatic arch. However, the incision is associated with a high risk of persisting edema of the upper eyelid [74, 75].
The combination of the upper gingivobuccal and lower transconjunctival incisions with approach through the lateral half of the superior conjunctival fornix allows one to avoid any complications typical of skin incisions [76, 77].
In the case of high-energy comminuted zygomaticoorbital injuries where visualization of the entire fractured area is crucial, a simple coronal incision is not sufficient. In this instance, the use of various modifications of bicoronal incisions (Fig. 6.10) combined with the transoral or transconjunctival approaches is necessary [80].
Fig. 6.10
Some approaches to the zygomaticoorbital fracture: (1) Conventional coronal incision and its modifications: zigzag “stealth” (2) and vertex (3) incisions used in patients with alopecia. (4) Limited or partial median horizontal approach used in patients with a combination of NOE and zygomaticoorbital fracture. (5) Preauricular approach. (6) Retroauricular approach. The figure does not show the periorbital and intraoral approaches that have been thoroughly described in the previous chapters
A combination of the upper gingivobuccal, lateral supratarsal, and preseptal transconjunctival approaches are most commonly used in practice.
Incisions and separation of soft tissues should be minimized to avoid late deformation of soft tissues but sufficient to adequately expose and reliably fix the fractures.
Zygomatic bone repositioning. If the zygomatic bone was slightly dislocated, closed repositioning according to the procedure proposed by Limberg [81–83] can be performed.
If the CT shows a significant dislocation in at least one point, especially when combined with comminuted fractures, open repositioning using instruments and approaches shown in Fig. 6.11a, b is needed. One should bear in mind that incorrect repositioning of zygomatic bone is associated with more severe complications than closed repositioning, wire fixation of bone fragments, or delayed surgical intervention.
Fig. 6.11
Zygomatic bone repositioning and fixation: (a) Closed repositioning. (b) Open repositioning using an instrument placed under the zygomatic bone via the intraoral approach. (c) The first stages of zygomatic bone fixation. Apposition of the frontozygomatic suture is performed through an incision continuing the supratarsal fold outward followed by plate placement on the sphenozygomatic suture (if needed). (d) The infraorbital rim is reconstructed through the transconjunctival approach. (e) Fixation of the zygomaticomaxillary suture. (f) Surgical outcome. (g) Bottom view of the zygomatic arch. As opposed to its name, this anatomic structure has a virtually linear shape. (h) The reconstructed zygomatic arch having a linear shape. (i, j) Plastic surgery reconstruction of an orbital floor defect with a titanium plate and polytetrafluoroethylene. (k, l) Facial soft tissue resuspension (see explanation in the text) (Materials from www.aofoundation.org were used for this illustration)
Principles behind fixation of the zygomatic bone. High-precision reconstruction of the zygomaticoorbital complex implies that four points are fixed (the lateral and infraorbital rims, the zygomaticomaxillary suture, and the zygomatic arch); the lateral orbital wall is additionally fixed in patients with very severe fractures. However, three-point fixation, without exposure of the zygomatic arch, is usually used in practice; if properly performed, this procedure restores the facial symmetry [6, 79, 84, 85].
The initial step to surgical repair is the apposition of the edges of the frontozygomatic suture which will determine the vertical dimension of the zygomaticoorbital complex (Fig. 6.11c). Regardless of the fact that the frontozygomatic suture is formed by thick bones that ideally suit rigid fixation, rather thin and short plates need to be used because of the thin layer of overlying soft tissues.
Another important aspect is the need for meticulous shaping of a miniplate to duplicate the contour of the lateral orbital rim to avoid redislocation of the zygomatic bone during screw tightening. Taking this fact into account, it is reasonable to perform final fixation of the frontozygomatic suture after the second, third, and fourth plates have been already placed. The frontozygomatic suture is temporarily immobilized during the surgery with a plate non-tightly fixed with two screws or temporary elastic sutures (rubber bands stretched between screws mounted in fracture edges) [86, 87].
The evaluation of the quality of zygomatic bone repositioning does not play any significant role, since even an obvious rotation of the zygomatic bone virtually does not change the configuration of the frontozygomatic suture [24].
The next stage, apposition of the infraorbital rim, plays the key role in zygomatic bone repositioning; however, effective rigid fixation of this fracture line cannot be achieved. Hence, a small and thin plate needs to be implanted here to minimize the risk of cicatricial eyelid deformation [85]. It is recommended that a titanium plate is placed on the superior rather than on the anterior surface of the infraorbital rim, where it could be easily palpated (Fig. 6.11c).
The zygomaticomaxillary suture is the best place for fixation as it provides direct countereffect to tractional forces of the masseter and is covered with a thick soft tissue layer, making it possible to use long and thick (2 mm) titanium plates and screws (Fig. 6.11d).
Thus, the completeness of zygomatic bone repositioning should be primarily evaluated based on the infraorbital rim; reliable fixation is ensured by placing titanium plates near the zygomaticomaxillary and frontozygomatic sutures.
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