MIDFACE FRACTURES
SOURCE: Dept. of Otolaryngology, UTMB, Grand Rounds
DATE: APRIL 17, 1996
RESIDENT PHYSICIAN: Michael Bryan, M.D.
FACULTY: Brian Driscoll, M.D.
SERIES EDITOR: Francis B. Quinn, Jr., M.D.

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"This material was prepared by resident physicians in partial fulfillment of educational requirements established for the Postgraduate Training Program of the UTMB Department of Otolaryngology/Head and Neck Surgery and was not intended for clinical use in its present form. It was prepared for the purpose of stimulating group discussion in a conference setting. No warranties, either express or implied, are made with respect to its accuracy, completeness, or timeliness. The material does not necessarily reflect the current or past opinions of members of the UTMB faculty and should not be used for purposes of diagnosis or treatment without consulting appropriate literature sources and informed professional opinion."

INTRODUCTION

Facial fractures are predominantly afflictions of the young (20-40 years old) male (M:F = 4:1). The number one cause of these injuries is motor vehicle accidents, followed by assault. Disruption of the facial skeleton distorts the patient's appearance, and may compromise the function of the masticatory system, ocular system, olfactory apparatus and nasal airway, etc. The facial skeleton is made up of thin segments of bone encased and supported by a more rigid framework of "buttresses". The midface is anchored to the cranium through this framework:

Vertical buttresses: nasomaxillary, zygomaticomaxillary, and pterygomaxillary Horizontal buttresses: frontal bar, orbital rims, zygomatic processes of temporal bone, the maxillary alveolus and palate, and serrated edges of the greater wing of the sphenoid

The buttress system absorbs and transmits forces applied to the facial skeleton. Masticatory forces are transmitted to the skull base primarily through the vertical buttresses, which are joined and additionally supported by the horizontal buttresses. The skull base itself a major component of the horizontal support framework, although not classically thought of as part of the buttress system. When external forces are applied, these components prevent disruption of the facial skeleton until a critical level is reached and then fractures occur. In any rigid structure, fractures occur at areas of weakness, and/or where stress concentrations occur. The areas where facial fractures tend to occur are weaker both collectively and individually, so that they tend to act like a "crumple zone" for the cranium and skull base when excessive force is absorbed. The classic fracture patterns described by LeFort in 1901 coincide with these areas of the facial skeleton, with fractures occur through the the junctions of horizontal and vertical buttresses, at suture lines, and thinner segments of bone.

Most facial trauma results in complex forces applied to the skeleton, with fracture patterns rarely being simply a classic unilateral or bilateral LeFort pattern. Fractures can be isolated or occur in combinations that blur the division between classifications. Comminution, crush injuries to the anterior maxillary wall, and zygomaticomaxillary complex fractures are very common and do not classically fit the LeFort classification.

APPROACH TO THE PATIENT

Patients with facial fractures may be a victims of multi-trauma, or have isolated facial injury. Multi-trauma patients will usually be evaluated by a trauma team and the facial injuries addressed after the patient is stabilized. The C-spine should always be assessed before any neck manipulation is allowed. However, midfacial injuries may be accompanied by airway problems or loss of consciousness with attendant need for airway stabilization. The conventional wisdom is to not transnasally intubate a patient with a suspected midface fracture. Airway stabilization in these patients, if necessary, should be achieved transorally, or via cricothyroidotomy/tracheotomy. If the C-spine is not clearedj, extension of the neck for intubation is contraindicated and a surgical airway may be required. Fortunately, Gussack et. al., found that only a small minority of patients with facial trauma require tracheostomy for their initial airway management.

Epistaxis is frequently seen in traumatic facial injuries, and hypovolemic shock or airway compromise can result secondary to profuse bleeding. This requires rapid intervention, and the principles of management are not altered in these cases except that the possibility of a skull base fracture must be considered when instrumenting the nose. Embolization or surgical ligation of bleeding sources are performed if local epistaxis control measures fail to control bleeding.

After the ABC's, the history and physical exam are performed. The most important goals to achieve are the recognition and treatment of intracranial injury, or CSF leak, or ophthalmologic injury. Visual acuity is the most important ophthalmologic exam, and should be performed promptly. Traumatic optic neuropathy or open globe injuries are emergencies and delay in treatment compromises outcome. Monocular diplopia is an indicator of globe or retinal injury, and likewise requires immediate ophthalmologic consultation. In the absence of findings that generate an emergent consult, the remaining eye exam is carried out. Evaluation of EOM may be compromised by edema of the soft tissues, and forced duction testing is required if there is suspicion of entrapment. Some studies show that almost 4 out of 5 midface fractures are associated with some kind of eye injury. The percentage here is less in recent experience, but we adhere to the policy of mandatory ophthalmologic consultation prior to any surgical repair involving the orbit.

In the absence of obvious CSF rhinorrhea, the patient should asked about a salty taste or post nasal drip. Active epistaxis will usually make this assessment unreliable. If a CSF leak is detected or suspected, the most likely sources are the frontal sinus, cribiform plate, or fovea ethmoidalis fractures. If a CSF leak is suspected, a thin cut CT scan through the skull base is indicated.

After ophthalmologic screening, the face, ears, nose mouth, and mandible should be methodically examined. The result of any bilateral LeFort fracture is a mobile midface, or if the fracture line is impacted, significant pain with attempt to mobilize the midface with traction on the maxillary central incisors or central maxillary alveolus. Look for asymmetry, facial shortening, facial elongation (not likely in the acute setting), raccoon eyes (raises the suspicion of skull base fractures or LeFort II), hypoesthesias, rhinorrhea or otorrhea, traumatic blindness, hemotympanum, restricted EOM, septal hematoma, trismus, and malocclusion. Systematic palpation of the bony prominences should be performed, looking for severe point tenderness or step offs. Most maxillary fractures present with palatal edema and ecchymosis. Dentition should be evaluated and oral surgery consultation requested if a complicated dentoalveolar injury is found. Fractured alveolar segments place the involved teeth at risk for pulp necrosis, and the risk increases commensurate with the amount of time that the segment remains mobile. Digital exam of the oral cavity is mandatory and may reveal discontinuities in the alveolar arch, or tenderness at the maxillary tuberosities indicating as seen in Lefort I and zygomatic complex fractures.

RADIOLOGY

If you suspect a midface fracture, get a CT scan. Plain films of the facial skeleton can be helpful, but a CT will invariably be ordered if there is any significant midface fracture. Panorex is advisable if a mandible fracture is found or suspected. 1.5 mm cuts should be requested. (In ancient days, a stereoscopic Waters and a basal skull view were of great help. /ed.)

TREATMENT

Stanley points out that treatment of facial injuries that affect multiple areas of the facial skeleton has historically been fragmented among specialists and that this approach does not always yield the best results. He argues for a primary specialist to perform the overall repair with a team approach when it is needed. This implies that the treating physician be well versed in the multitude of treatment options available.

The goal of treatment is to reestablish skeletal relationships while restoring and/or preserving function of vital structures. The most important concerns are the restoration of dental occlusion, ocular position, ocular mobility, and orbital volume. Aesthetics are important but secondary to the foregoing. The basic principle is to reconstruct from two areas of reference: the cranium and the dental occlusion. The face hangs from the skull base and this in turn is rigidly fixed to the cranium. Rebuilding "from the top down" and from the sides in allows proper facial dimensions and orientation to be reconstructed. If open treatment is indicated, adequate exposure is paramount with reduction and fixation of fractured elements to stable reference points. Inferiorly, the dental occlusion must be restored prior to fracture repair to preserve function of the masticatory system. Therefore, MMF/IMF, whether performed and removed intraoperatively or left in place postoperatively, is often the first step in repair of facial fractures. Anytime the palate/alveolar buttress system is not stable relative to the skull base, MMF/IMF should be the first step unless contraindicated for some other reason. However, it should never be used to "pull" the patient into occlusion.

The timing of treatment of facial fractures is the subject of some controversy. Although some advocate immediate repair in the stable patient, no significant deleterious effects appear to result from a delay of 7 to 14 days, which may allow edema to diminish and provide easier manipulation of bones and soft tissue. Waiting longer than this is not preferred because fibrosis and healing begin to occur, making late repair more difficult. Soft tissue envelope contraction is cited as the major cause of difficulty and poor outcome in late correction of post traumatic defects. Circumstances that may mandate delayed repair are when the patient is not stable or has an increased ICP. Derdyn, et. al., performed a retrospective study evaluating the outcome of treatment of patients who sustained combined neurologic injury and facial fractures and found that patients with an ICP of greater than 15 mmHg tended to do worse with early fracture repair. They also found that upper and midface injured patients had worse outcomes than lower level facial injuries.

Early fracture repair (<3 days) in patients with an ICP of less than 15 was not associated with a significant increase in morbidity or mortality. The presence of a CSF leak is not an absolute contraindication to early repair of fractures, but Derdyn et. al. noted that if ICP is borderline preoperatively, the repair of fractures and concomitant treatment of the leak may result in an increased ICP postoperatively. Their recommendations included intraoperative ICP monitoring of patients with significant neurologic injury undergoing facial fracture repair. Other relative contraindications to early repair are GCS of 5 or less, evidence of intracranial hemorrhage, midline intracranial shift, and basal cistern effacement on CT, all of which are associated with poor prognosis.

Closed Reduction vs Open Reduction and Fixation

The treating physician will have to decide whether to use closed reduction or ORIF techniques to repair facial fractures. In the past few years there has been a great emphasis on ORIF techniques, specifically rigid and semi-rigid plating. Closed reduction was used more widely prior to the availability of plating systems, but by no means is outdated. Fractures that can be manipulated into reduction, are stable to palpation, and have no muscular distracting forces applied to them can be treated in this manner. It is generally agreed that fractures with significant displacement, comminution, or those where muscle actions distract or rotate across fracture lines should be treated with ORIF techniques. Possible exceptions are comminuted nasal bone or isolated maxillary sinus wall fractures without loss of buttress support. Controversy exists over the closed reduction treatment of zygomatic complex and depressed zygomatic arch fractures.

Gruss has written extensively about zygomatic fractures and is an advocate of open reduction and fixation for the most part, but states that "...if the surgeon assesses that there is minimal displacement at all five sites of fracture with no comminution, then it is highly likely that the periosteal hinge is still present at the majority of fracture sites, and a simple elevation of the fracture by means of a Gillies or intraoral approach can be attempted." The lack of a consensus on this topic is reflected in the variability of subjective surgical judgement, generating reports of the frequency of "stable" zygomatic fracture reduction ranging from 16% to 92%. (I have been trying to teach this to my residents for years. /ed.)

Open Fracture Fixation Methods

Regardless of the type of fixation employed, the surgeon should keep in mind the principles of bone growth and healing. Periosteum should be conservatively elevated to prevent devascularization of more bone than is necessary. Significant gaps (greater than 5 mm) between bone fragments should be considered for bone grafting. Membranous bone (eg - calvarial bone) is more reliable and resorbed less than other bone stock (eg - endochondral bone from rib or iliac). Interfragment gaps smaller than 5 mm can be spanned by plates or wires (preferably plates).

The use of mini and micro plating systems have become the norm in treatment of facial fractures. The surgeon should be able to use these systems and apply them appropriately. Taicher and Ardekian found a reduced incidence of neurologic injury when miniplate fixation was used to repair zygomatic complex fractures versus other methods. This was reinforced by Rohrich and Watumulla in a retrospective review of patients with zygomatic complex fractures treated by various methods of fixation at a large urban trauma center. They found that patients treated with rigid fixation systems suffered less late post-operative deformity and neurologic deficits than those treated with wire fixation or simple reduction. In their study, half of the zygomatic complex fractures treated with reduction only had postoperative malar flattening. The authors suspect that this could have been secondary to poor patient selection and acknowledge that two previous studies reported good long term results with closed reduction of zygomatic fractures that were stable to palpation after reduction. Nevertheless, this clinical study bears out the predictions of anatomic studies by Davidson, Rhinehart, and O'Hara, all demonstrating the superiority of plating systems to alternative methods of fixation when there is significant dynamic load that may act to distract or mobilize the fracture, such as in zygomatic fractures.

Interestingly, Davidson's study reported that three point interosseous wiring resulted in a stable configuration, but the maximum force applied to the reduced fracture was 5.5 kg, whereas a normal zygoma can be subjected to forces as high as 120 kg in dentulous patients and 50 kg in edentulous patients. Del Santo et al showed that patients with zygoma fractures don't generate normal levels of masseteric force, but still significantly higher than the 5.5 kg used by Davidson. Rhinehart basically repeated Davidson's study using loads of up 45 kg and found that three point wire fixation did not prevent rotation, but two point rigid fixation did. O'Hara et al repeated the experiment with a twist: they used forces similar to those thought to be possible in patients with zygoma fractures (2 to 22 kg) but employed microplates in their combinations of fixation devices. O'Hara found that the combination of a miniplate at the ZM buttress and a microplate at the FZ suture line yielded acceptable stability, and that the addition of a microplate to the inferior orbital rim added little. Combinations of miniplates and microplates proved to be more stable than corresponding miniplate-wire combinations.

The use of rigid fixation techniques have been associated with a higher incidence of infections and complications in some applications. Separate studies by Leach and El-Degwi demonstrate a higher rate of postoperative infection with the use of rigid mandibular fixation. However, reviews of rigid fixation in the repair of midface fractures (Macias et. al.) do not reveal the same problems with infection or other postoperative complication. The incidence of postoperative infection is believed to be about 5-10% with ORIF of midface fractures. The most common complication of rigid fixation techniques in midface fracture repair has been pointed out by Gruss, who states that there appears to be an "epidemic" of patients showing up in craniofacial surgeons offices with problems related to improperly reduced fractures that were fixed in position with rigid plating systems by other surgeons. The rigid plating systems may in fact magnify this type of problem whereas less rigid fixation may be more forgiving. These problems aside, there is near universal acceptance that rigid plating of midfacial fractures is effective and safe when properly performed.

Miniplate systems provide a significant amount of rigidity and strength and are applicable in just about any area of the facial skeleton. Relative contraindications to their use are in cases where the plate will be obtrusive or cosmetically obvious. Cosmetic concerns should not compromise a repair because the plates can be removed after healing has occurred if they are aesthetically problematic. Microplates have been specifically to be used where there is a need to establish a spatial relationship but rigidity is a secondary concern. They may offer a solution in areas where the thicker miniplates will be noticeable, but their use as the sole fixation device when one or both of the reduced/fixed bones is subject to the stress of muscular attachment has not generally been acceptable. To overcome this problem, some surgeons have reported good results by using multiple (usually two) microplates side by side across a fracture line. Long term follow up is not available, but initial results with multipoint microfixation were reported to be good.

An area of ongoing research is in the use of biodegradable plate systems. Several investigators have achieved excellent results when utilizing polyactic-polyglycolic acid copolymer plates and screws in animal models. Bony union equivalent to that produced with the use of titanium systems of similar thickness was obtained. The plates and screws completely resorbed within one year and produced no inflammatory reaction. These systems are apparently being used on a limited basis in Europe now and there have been a few complications including sterile fistulization over the sites of screws, so the use of these devices is not widespread. Impregnation of the materials with antibiotics and growth factors has been proposed but not tried yet. Continued development of these devices is certain, especially because of the potential reduction in the effects on bone growth in pediatric patients (see below).

Because of the growth of popularity of rigid fixation systems, wire fixation is not as popular as it once was, but still is a useful method of fracture fixation. As mentioned above, some studies have shown that even three point wire fixation may not adequately stabilize some fractures, but biomechanical testing is not equivalent to in vivo situations and historical evidence would suggests otherwise. Advocates of interosseous wiring point to the apparent correlation of the advent of rigid plating and an increase in the number of patients seeking secondary correction of facial and orbital defects after primary rigid fixation.

Considerations in Pediatric Patients

Sadove and Epply have used microplate and miniplate fixation in a large number of pediatric craniofacial procedures and report excellent results, but emphasize that the long term effects of rigid plating systems on pediatric facial growth and development are unclear: Current experimental evidence consistently indicates that some degree of bone growth restriction occurs after placement of bone plates in the growing cranium. They recommend more conservative use of rigid plating systems in children. Fortunately, the incidence of midface frac population. This is thought to be due to the relative lack of pneumatization of the pediatric maxilla, the relative protection of the midface because of the increased cranium to midface size ratio, and the generally softer bone structure (Gussack et al).

Specific Fractures

LeFort I

Results from application of horizontal force just above the apices of the maxillary teeth. The fracture extends through lateral nasal wall and pyriform aperture across the maxillary alveolus and antral walls to the pterygoid plates; if unilateral, there will likely be a fracture along the palate and through the alveolus at some location anatomically described above. The characteristic finding is an anterior open bite due to the medial and inferior traction of the medial and lateral pterygoids on the mobile maxillary fragment. The alveolar arch may me mobile, but is often mildly impacted. Early reduction of mobile fractures is fairly easy, but delayed repair or impacted fractures must be managed with disimpaction forceps. Rowe forceps are applied to the nasal floor and hard palate, or Hayton-Williams forceps are placed behind the maxillary tuberosities intraorally. A rocking motion with constant anterior traction frees the impacted segment. Non-comminuted fractures can be treated with simple MMF for 4 weeks, without the need for suspension wires.

Alternatively, interosseous wiring can be used without postoperative MMF, but a soft diet is indicated for several weeks. Rigid plating allows early function, but reduction and plate conformation must be perfect. Intraoperative MMF with the mandible passively positioned is paramount. Comminuted fractures that are not amenable to plate or wire fixation are treated with MMF and suspension. The arch bar of the maxilla is suspended from the pyriform, zygomatic arch, the orbital rims, or extraskeletally to a halo in patients who have extensive facial comminution. Palatal fractures are not infrequently associated with LeFort I fractures, and are treated directly with interosseous wire, plating, or with a palatal splint affixed to intact dentition. Edentulous patients are treated the same way except that if interosseous fixation is not possible, either a custom acrylic occlusal splint or the patients own denture is used to define the occlusion, which is less critical in these patients. If rigid fixation is performed, the MMF can removed at the end of the case. If this is done occlusion should be rechecked with the jaw passively manipulated. Malocclusion at this stage must be corrected.

LeFort II

Also known as a pyramidal fracture, the LeFort II is a result of force applied near the level of the nasal bones. Fractures extend through the nasofrontal suture lines, the lacrimal bones, the inferior orbital rims, across the maxillas at or near the zygomaticomaxillary suture lines, and down through lateral maxillary sinus walls, and through the pterygoid plates. Like the LeFort I, the inferior and posterior pull of the pterygoids can cause an anterior open bite deformity. Other classic features are "raccoon eyes", hypoesthesia of CN V2, a mobile midface, and sometimes step offs at the infraorbital rims or nasofrontal junction that gets worse with palatal traction. Orbital wall fractures can cause entrapment, usually involving medial rectus; look for loss of abduction and adduction. CSF rhinorrhea is possible and should be looked for. The medial canthal tendon can be disrupted and must be repaired (see nasoethmoid fractures above).

Repair begins with MMF/IMF to establish occlusion. Disimpaction may be necessary using the Rowe forceps. Once occlusion is established, the patient can be treated with suspension from the maxillary arch bar to the zygomatic arches, lateral orbital rims or superior orbital rims with 24 gauge wire. Open treatment can be carried out by exposing, reducing, and wiring or plating the inferior orbital rim fracture. Medial canthal incisions can be created for access to the medial canthal tendon and/or reduction fixation of the nasofrontal area performed with wires or plates. Labiobuccal or inferior rim incisions can provide exposure of the ZM suture for fixation with wires or plates. If rigid fixation is performed, the MMF/IMF can removed at the end of the case. If this is done occlusion should be rechecked with the jaw passively manipulated. Malocclusion at this stage must be corrected.

LeFort III

Results from force at the level of the orbit and differs from the LeFort II in its pattern through the lateral orbit. It is most likely secondary to more force lateral to the midline than in a LeFort II. Fractures extend through the nasofrontal sutures, the medial orbital walls, through the inferior orbital fissures to the lateral orbital wall at the zygomaticofrontal suture, and across the zygomaticotemporal suture. The result of bilateral Lefort III fractures is "craniofacial dysjunction , which gives a characteristic dish face appearance with elongation and retrusionof the lower and midface.

The principle of repair is the same as for other LeForts, and multiple approaches are necessary. The bicoronal flap combined with the midfacial degloving allow maximal exposure, but multiple discontinuous approaches, such as the labiobuccal, lateral brow, inferior rim, and the open sky are frequently used, thus maintaining attachement of the soft tissues to the stable skeleton maximally.

Blowout

A true blowout fracture is due to direct frontal application of force to the orbit by an object that is larger than the orbital rim circumference, resulting in retrograde displacement of the globe and an increase in intraorbital pressure. This leads to fractures of the medial wall and/or floor, which are 0.25 mm thick and 0.5 mm thick respectively. There is no communicating rim fracture. These injuries may be accompanied by ocular injury, entrapment, enophthalmos, or they may be asymptomatic. A thorough ophthalmologic exam is indicated. An afferent pupillary defect is an emergency and lateral canthotomy with cantholysis is indicated if there is any evidence of increased orbital pressure (ballotte the globe with the lid closed). Enophthalmos and/or entrapment must be addressed and forced ductions performed. The decision of whether to treat the fracture depends on these factors as well as CT scan findings. If there is significant enophthalmos, or the forced ductions are positive, treatment is indicated to restore the orbital volume and freedom of movement. Diplopia with negative forced duction testing is probably due to edema and can be observed. If it persists for greater than two weeks, or late enophthalmos appears as the swelling subsides, most experts advocate exploration and repair.

Surgery for diplopia without clear evidence of entrapment is a little controversial because a large series of patients has demonstrated that the vast majority (>95%) of patients will have no symptoms in six months. Residual enophthalmos of less than 2 mm can be observed. The repair is via a transconjunctival, subciliary, inferior fornix, or lower lid approach. The floor can be repaired with bone grafts (calvarial bone is ideal), fascia (for small defects), or allograft materials. Titanium mesh is an excellent choice for floor reconstruction. Gelfilm has been used successfully in cases of small defects. Silastic sheeting should probably be avoided as it has an increased incidence of late complications requiring removal (Morrison, et. al.) . Intraoperative forced duction testing is mandatory to ensure that no residual entrapment remains. The orbit naturally has a concavity just posterior to the inferior and superior rims, and when repairing a floor fracture, recreation of this profile is desirable. This can be accomplished by maintaining the anterior edge of any graft posterior and inferior to the orbital rim. This also minimizes the possibility of graft migration. The use of titanium mesh fixed to the orbital rim negates the concern of migration.

Nasoethmoid fractures

Results from a frontal blow of high energy at the level of the nasal bones. There is collapse and telescoping of the nasal bones and anterior ethmoids, and may be a fracture of the cribiform and fovea ethmoidalis. CSF leaks should be suspected. Traumatic telecanthus results from the disruption of the medial canthal tendon or the comminution of the bone it is attached to. Inadequate treatment leads to permanent telecanthus, flattened nasal bridge and rounding of the palpebral fissure. It is almost impossible to overcorrect the telecanthus surgically, and overcorrection at surgery is the goal. If the medial canthal ligament has been avulsed form the bone a transnasal canthopexy is performed by passing a 28 gauge wire through it at its origin (medial to the point where it separates into its 3 components,) and passing the wire transnasally. If the wire cannot be passed for some reason, a microplate can be secured to the remnants of stable bone and the tendon secured to it with permanent suture. This is always done as a last step prior to closure because a lax lid apparatus allows easier soft tissue manipulation in the area. If necessary, dorsal augmentation can be carried out, usually best done with a calvarial bone graft. When using microplates (or miniplates) in the area of the nasal bones or the distal nasal process of the frontal bone process, Sadove and Eppley recommend using screws no longer than 5 mm. Access to the area can be achieved through medial canthal incisons that can be connected in an H to create an open sky approach. Alternatively, the coronal approach can be extended over this area.

Zygomatic complex fractures

Also known as trimalar fractures which is a misnomer. This is really a quadrapod fracture, as a result of disarticulation of the zygoma with the frontal, maxillary, sphenoid and temporal bones. These fractures typically result from a forces directed posteromedially impacting on the malar eminence. The fractures interconnect and are usually through the FZ & lateral orbit, across the ZM buttress, the inferior orbital rim & floor, and the lateral maxillary wall. The lateral orbital fracture connects to the inferior orbital fracture through the inferior orbital fissure. Often these intraorbital components are non- or minimally displaced and difficult to detect on CT scan. A fifth are of fracture is the zygomatic arch, usually just posterior to the zygoma. The arch may be fractures in more than one place, leading to a free depressed segment. Because of their complex three dimensional configuration, zygomatic fractures are notoriously difficult to completely reduce and fix in position while maintaining reduction. Because of the masseter pull on the zygomatic arch, these fractures have a propensity to become displaced with inadequate fixation.

Biomechanical analysis have been performed to evaluate the most efficacious way of repairing these fractures. As noted above, Davidson, Rhinehart, and O'Hara have probably done the most logical studies, but controversy still exists. Despite their studies demonstrating the superiority of rigid fixation involving at least two sites, the prevailing method utilized in a survey of over 200 surgeons in Great Britain was the Gillies incision with FZ rigid fixation only. While some have apparently achieved good results with these methods, the evidence suggests that this may not consistently work. The FZ suture line is the least useful site to detect the degree of rotation of the fracture because many rotated and displaced fractures will not appear significantly displaced at the FZ. Additionally the stability of a single plate at the FZ is questionable under dynamic loads. The importance of proper repair can be seen in patients who have undergone insufficient reduction and/or fixation of the zygomatic complex fracture. They typically have flattening of the malar eminence, facial widening on the affected side, and frequently have unequal pupillary height with enophthalmos secondary to inadequately treated orbital wall fractures causing increased orbital volume.

If open reduction/fixation is to be done, good visualization is necessary to ensure adequate anatomic reduction of displaced fractures. Multiple approaches are usually necessary, most often incorporating labiobuccal, transconjunctival (or subciliary), lateral brow incisions and or Gillies incisions. Coronal and hemicoronal approaches can be used, especially if fixation of the zygomatic arch is planned. This is a slightly controversial point as some authors insist that reduction and fixation of the arch is the key to obtaining a good result in cases where there is a displaced arch fracture. Gruss has written extensively about these injuries and is a major proponent of this technique. He stresses the need for exploration and reduction/fixation based on late post operative assymmetries after craniofacial procedures wherein other areas of rigid fixation were relied on to maintain midfacial projection, and the arch was reduced but not fixed. This seems to contradict results of some biomechanical studies (see below).

Surgical Approaches

Multiple approaches are often required to achieve the necessary exposure in cases where open reduction is required. One obvious methods of direct access through a facial wound. Other common routes are via labiobuccal, Gillies, and lateral brow incisions will not be discussed here.

Coronal & Hemicoronal

This approach allows excellent exposure of the entire frontal area and can be extended to allow access the lateral orbital wall & rim, the brow and nasofrontal area, and the zygomatic arches. The flap is elevated in the subgaleal plane until just above the supraorbital rims, at which point the periosteum is incised and a subperiosteal plane dissection continued down over nasal area. The most important principle of the flap is that as it is elevated over the temporal region, the plane of dissection just above the superficial layer of the deep temporal fascia until the dissection is approximately 2 cm away from the zygomatic arch. At this point the deep temporal fascia has split into two layers and the outer layer is incised at a 45 degree angle from the horizontal directed anteriorly/superiorly. The temporal fat pad is encountered and followed down to the zygomatic arch, reflecting the temporal fascia laterally and thus preventing injury to the frontal branch of the facial nerve. The arch can then be manipulated and repaired. Frodel and Marrentette give an excellent description of the anatomy and surgical technique using this approach. The use of this approach gives excellent cosmetic results unless the patient has or develops male pattern baldness.

Midfacial Degloving

This technique was described some time ago, but not widely used until its reintroduction by Maniglia. The degloving approach allows the soft tissue envelope of the midface to be elevated in continuity by combining a wide labiobuccal approach with release of the soft tissue from the piriform aperture and nasal skeleton. By combining this method with the coronal approach, almost the entire facial skeleton can be exposed. At the end of the procedure, some authors insist that the surgeon should redrape the soft tissue envelope and secure the periosteum to the bony skeleton through either closure of sites of periosteal incisions, or by passing small tacking sutures through holes drilled in the bone.

Transconjunctival/Subciliary

These approaches allow access to the inferior orbital rim, infraorbital area, and orbital floor. The relative advantages of the subciliary approach are that is less time consuming and there is less risk to the cornea. Hammer, et. Al., recommend against a subcilary approach if the patient has already undergone a previous subciliary incision. In the population that requires treatment for facial fracture this is not a superfluous recommendation. The transconjunctival approach leaves no visible scar and when combined with a lateral canthotomy, provides wider exposure to include the lateral orbital rim. Some use the lateral canthotomy extension to gain access to the FZ suture, negating the need for an external incision in this area. The risk of damage to the globe is small, and there are few reports of postoperative ectropion of the lower lid. There are two methods of transconjunctival exposure: preseptal and trans- or retro-septal. There are advocates of both, but the preseptal approach has not been shown to cause any increase in ectropion and it affords the luxury of not having to deal with prolapsing orbital fat in the surgical field. The lateral canthal tendon must be repaired if a cantholysis is performed, and it should be slightly overcorrected in the superior direction.

Transantral

This is basically the Caldwell-Luc approach and is easily utilized in cases where there is a defect in the anterior maxillary wall, giving direct access to the orbital floor, lateral nasal wall, and inner aspects of the zygoma and zygomaticomaxillary buttress. This access can be used prior to repair of the anterior maxillary wall, or the defect can be left unrepaired if it is small. Alternatively, a defect can be created surgically. Through this opening, elevators or other instruments such as urethral sounds (see below) can be used to assist in reduction of fractures. Maxillary sinus packing to support an isolated lateral nasal wall or orbital floor fracture can also be introduced through the opening, with the end of the packing material brought out through the defect or through a nasoantral window.

Nasoantral window

This method of access to the inner surface of the zygoma has been useful in cases where reduction of the zygoma is difficult and there is a desire to avoid additional surgical approaches. It can be utilized in combination with other approaches or alone incases where closed reduction is planned. Although there is a dearth of published descriptions of this method, Dr. Quinn has been an advocate of it and it has been used successfully at this institution many times. The technique requires the creation of a nasoantral window under the inferior turbinate to allow the introduction of a curved urethral sound into the maxillary sinus. The sound is advanced until the blunt tip of it is against the hollow of the interior surface of the zygoma. By applying manual pressure over the zygoma while maintaining pressure on the inner surface of the zygoma with the sound, the zygoma can be fairly easily manipulated bimanually. Palpation of the fracture lines and or the malar eminence is used to evaluate the reduction. Internal fixation can then be carried out if needed.

COMPLICATIONS

Malunion

Usually the result of improper reduction and fixation, resulting in malocclusion, facial asymmetry, enophthalmos, ocular dystopia, etc. Secondary repair is much more difficult to carry out and may result in legal action. The only method of prevention is meticulous technique.

CSF leak

Although not common, CSF leaks that were not noted preoperatively have been reported after the treatment of midface fractures, most commonly NASOETHMOID, LeFort II and LeFort III fractures. Fractures through the cribiform or fovea ethmoidalis are the most common causes. Obviously frontal sinus fractures which can occur in conjunction with midface fractures are another common source. CSF leaks predispose to meningitis and cases of meningitis secondary to post-traumatic CSF leaks have been reported as many as 12 years after the injury.

Epiphora

Injuries to the lacrimal system either from trauma at the time of injury or iatrogenic secondary of ORIF can result in epiphora. Post traumatic ectropion, again from injury or secondary to lower lid surgical approaches can also lead to epiphora. Lacrimal injuries usually require dacrocystorhinostomy, and ectropion requires a lid tightening procedure.

Globe injuries

The more common of these would include injury to the cornea (eg - secondary to injuring transconjunctival approach), or penetrating injuries form scalpels, wires or drill bits. Fortunately these are exceedingly rare in literature reports. Ophthalmologic consultation is mandatory in these injuries, and any c/o of eye pain or feelings of foreign body in the eye after surgery must be evaluated. Fluorescein drops on the cornea can demonstrate abrasions or lacerations, but even if this is not evident, persistent ocular c/os must not be ignored.

EOM Entrapment

During the reduction of midface fractures, an already fractured orbital floor can be mobilized inadvertently and cause herniation or entrapment of the inferior rectus. Orbital floor exploration and reconstruction should performed after other related fractures are repaired to prevent this post operative complication. Immediate postoperative impairment of EOM can be due to swelling or local anesthetic infiltration. Persistent ophthalmoplegia requires forced duction testing to rule out entrapment. Re-exploration and repair is preformed to correct this.

Pulfrich phenomenon (trivia time)

Larkin reported a relatively rare post traumatic disturbance of stereoscopic vision known as the Pulfrich effect. He found that in 6 out of 187 patients with midfacial fractures, the phenomenon could be demonstrated and 5 of these patients were symptomatic. The phenomenon occurs because of a slight interocular time difference in the transmission of information from the retinas. When this occurs, the visual cortex compensates by creating a visual impression of a moving object at an intermediate location between the point where the object actually was at the time the affected eye "saw" it and where it actually is as perceived by the unaffected eye. The net result is a visual disturbance causing objects moving in a straight line to be perceived as moving in a curvilinear manner. This can be debilitating in some situations, for example when driving a vehicle, the oncoming traffic will appear to crossing the center line and veering into the path of the affected driver. The treatment is a simple neutral density filter in front of the normal eye.

Convergence insufficiency and failure of accommodation

Al-Qurainy described this phenomenon that can occur after midfacial trauma. The mechanism is not clear, and there was no relationship detected between the incidence of this and the type of fracture sustained. It is postulated that the problem may be related to the force of impact and concomitant cerebral concussion. About 20% of these patients do not appear to recover and treatment with orthoptic exercises does not help.

SUMMARY

Midface fractures are most often sen in young adult males.

Children have a low incidence of midfacial fractures; probably due to the relatively larger cranial size, and the lack of complete maxillary sinus pneumatization.

Intracranial injuries, CSF leaks, and ocular injuries must be suspected and ruled out in patients with facial injuries.

Increased intracranial pressure (>15 mmHg) is a relative contraindication to proceeding with repair of facial fractures in patients with concomitant head injuries.

There is little difference in the outcome of stable patients whose fractures are treated very early versus those treated in a more delayed fashion.

Rigid and semirigid plating systems perform well with few complications when used to repair midfacial fractures provided proper reduction is obtained.

The dental occlusion must be used as the lower frame of reference when treating fractures that result in instability of the maxillary alveolus relative to the skull base.

Interdental wiring should never be used to "pull" the patient into occlusion during the repair of fractures.

The most common complication after rigid repair of facial fractures appears to be malunion secondary to inadequate reduction.

Bone grafting should be considered in the repair of comminuted fractures that result in gaps of > 5 mm between segments.

Membranous bone is generally a better substrate for bone grafting in the face.

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