Craniomaxillofacial Trauma Surgery

CC

A 22-year-old male presents to the oral and maxillofacial surgery office complaining of anterior facial pain, swelling, oral bleeding, and mobile teeth.

HPI

The patient reports that he was riding his mountain bike when an abrupt bump resulted in him striking his lower face against the handlebars. He dismounted the bicycle without other injuries and drove himself to an outside emergency department. He denies loss of consciousness, nausea, vomiting, visual disturbances, or headache (indicative of head trauma with intracranial injury). He further denies stridor, dyspnea, or increased work of breathing (suggestive of foreign body aspiration resulting from dislodged teeth, dental restorations, or orthodontic appliances). He notes several dental fractures, profound mobility of the lower teeth, and gingival bleeding. He undergoes primary and secondary surveys, according to the ATLS protocol, that are found to be negative. A computed tomography (CT) scan is obtained, and the patient is given instructions to report by private car to your office for evaluation.

PMHX/PDHX/Medications/Allergies/SH/FH

The patient denies any significant cardiac, pulmonary, renal, hepatic, or neurologic diseases.

Examination

General. The patient is a well-developed, well-nourished adult male in mild distress secondary to pain and oral bleeding. He is neurologically intact.

Maxillofacial. There are no lacerations, contusions, or abrasions of the scalp, midface, or chin. The pupils are equal at 4 mm, round, and reactive to light and accommodation. The nasal dorsum is midline and stable. There is no rhinorrhea (a concern for violation of the cribriform plate with cerebrospinal fluid [CSF] leakage) and no septal hematoma on speculum examination. The ears are symmetric and without injury to the pinnae. Examination of the external auditory meatus reveals no otorrhea (also a concern for CSF leakage) or disruption of the tympanic membrane. There is no mastoid ecchymosis noted (Battle's sign, significant for occult skull base fracture). The orbits, midface, and mandible are without step deformity or crepitus on palpation. Cranial nerves II through XII are intact.

Intraoral. There is a 1-cm abrasion of the upper lip skin without significant laceration. Intraorally, there is profound ecchymosis of the upper lip mucosa with a laceration extending into the sublabial vestibule ( Figure 8-1 ). Teeth #7 and #8 are mobile as a single unit with displacement of the buccal cortical plate on manipulation. Tooth #9 is grossly mobile and subluxed several millimeters. It also demonstrates an oblique coronal fracture with pinpoint pulp exposure (Ellis class III). In addition, tooth #9 is sensitive to mechanical stimulation with a cotton-tipped applicator and tender to percussion. There is occlusal prematurity with interference of the maxillary anterior teeth on attempted intercuspation.

Imaging

A maxillofacial CT scan demonstrates an alveolar segment fracture involving teeth #7 and #8, with subluxation of tooth #9 and fracture of the alveolar plate ( Figure 8-2 ). There are otherwise no injuries to the maxillofacial skeleton, cervical spine, brain, or cranium. The minimum radiographic study necessary for diagnosis of dentoalveolar fractures is a periapical radiograph, although the diagnosis can often be made with a physical examination alone. Based on availability, other radiographic studies may include:

• Computed tomography

• Cone-beam CT (CBCT)

• Periapical radiograph with horizontally and laterally directed central beam to evaluate traumatized roots for fractures

• Occlusal view

• Panoramic radiograph

Labs

No routine laboratory tests are indicated for the work-up and diagnosis of dentoalveolar injuries in the healthy individual. If coagulopathy is suspected based on the medical history and physical exam, a coagulation profile, including the prothrombin time/partial thromboplastin time (PT/PTT), international normalized ratio (INR), and platelet count, may be obtained.

Assessment

Anterior maxillary alveolar segment fractures involving teeth #7 through #9, with lateral luxation and an Ellis class III fracture of tooth #9, and an intraoral laceration of the upper lip.

Treatment

Initial stabilization includes reduction of the teeth and splinting ( Figure 8-3 ). With the current patient, bonded flexible wire splinting was not available, so the teeth were splinted with an arch bar. The occlusion was checked, and the teeth were not in occlusion during maximum intercuspation. The patient's tetnus status was up to date. He was given a prescription for amoxicillin and chlorhexidine and discharged home. The teeth were splinted for 8 weeks because of the alveolar segment fracture. Root canal therapy was initiated on day 10 with calcium hydroxide therapy.

Complications

In the past, only about 25% to 40% of replanted, avulsed teeth show periodontal ligament (PDL) healing. This has been attributed to poor handling of the tooth. Three different types of posttraumatic external root resorption have been distinguished in the literature: surface resorption (repair-related root resorption), inflammatory resorption (infection-related root resorption) and replacement resorption (ankylosis-related root resorption). Surface resorption has no significant clinical consequences and can be observed. However, the other types of resorption can ultimately result in tooth loss. In the avulsed tooth, if the PDL that is still attached to the tooth does not dry out, the cells can remain viable for an extended period, depending on the storage medium. Once the tooth has been reimplanted and stabilized, the viable PDL cells reattach to the PDL within the socket. When the injury to the cementum of the root is localized, there is minimal destructive inflammation, allowing for new cementum to be laid down after the inflammation resolves. When there is poor handling of the avulsed tooth (e.g., drying or storage in nonphysiologic solutions), damage and necrosis of the PDL occur. Subsequently, there is a large area of inflammation to remove the damaged PDL and cementum. This must be replaced by new tissue. The slower moving cementoblasts compete with the osteoblasts in the replacement process, resulting in some areas of the root surface being replaced by bone. Over time, through osseous remodeling, this can result in osseous or replacement resorption. Internal root resorption can occur through persistent inflammation or metaplastic replacement of normal pulp tissue. This can result in late tooth fractures. Root surface treatments and root canal therapy are directed toward prevention of this complication. Ideal management of dentoalveolar trauma may have to be delayed due to life-threatening injuries that must be managed first ( Figure 8-4 ). This may result in resorptive complications.

Discusson

Appropriate diagnosis is critical in identifying and treating dentoalveolar injuries, which are known to affect one fourth of all children and one third of all adults. Depending on the mechanism of injury, a number of maxillofacial injuries may present with concomitant intracranial or cervical spine injuries, despite normal neurologic findings on physical examination. After a thorough physical examination that follows the ATLS protocol, attention is directed to the head and neck. Contaminated facial wounds should be irrigated with normal saline if available, although tap water has been shown to be as effective as saline. Patients with grossly contaminated wounds or facial injuries caused by dog or human bites should be considered for tetanus immunization based on their vaccination history. If an adult has an ambiguous immunization history or has received fewer than three prior doses of tetanus toxoid, he or she should receive tetanus immune globulin (TIG) and the tetanus-diphtheria (Td) or tetanus-diphtheria-acellular pertussis (Tdap) vaccine. Prior tetanus disease is inadequate at providing immunity, because a small amount of the highly potent toxin is sufficient to cause clinical neuromuscular weakness and airway compromise. Antibiotic coverage must be based on the mechanism and extent of injury. It is indicated in contaminated wounds with significant soft tissue injury, luxated teeth, avulsed teeth, pulp exposures, root fractures and alveolar fractures. Amoxicillin is usually chosen unless the patient is allergic to penicillin; in such cases, clindamycin can be substituted. Chlorhexidine oral rinse is an excellent choice for most oral injuries to help prevent infection.

The cause of dentoalveolar trauma varies among different demographics, but it generally results from falls, playground accidents, domestic violence, bicycle accidents, motor vehicle accidents, assaults, altercations, and sports injuries. Gassner and colleagues reported an incidence of 48.25% in all facial injuries, 57.8% in play and household accidents, 50.1% in sports accidents, 38.6% in accidents at work, 35.8% in acts of violence, 34.2% in traffic accidents, and 31% in unspecified accidents. Falling is the primary cause of dentoalveolar trauma in early childhood. Andreasen reported a bimodal trend in the peak incidence of dentoalveolar trauma in children aged 2 to 4 and 8 to 10 years.

Dentoalveolar injuries have been classified by the International Association of Dental Traumatology, which regularly reviews and updates its guidelines and publishes them online at www.dentaltraumaguide.org . Broadly, the discrete categories of dentoalveolar injury include:

• Injuries to the periodontium

• Injuries to the dental crown and root

• Injuries to the supporting alveolar bone

Injuries to the periodontium resulting from forces directed through the tooth and to the surrounding bone and periodontal attachment are the most common types of dental trauma in the primary dentition.

CC

A 21-year-old man comes to the local emergency department, stating, “I fell and cut my chin.” You are asked to evaluate this patient.

Falls show a greater proportion of subcondylar fractures compared with other fracture patterns; the role of the dentition and the influence of open versus closed mouth position are likely of minor importance. The force from direct blunt trauma at the chin (symphysis) in a fall is transmitted to the condylar region and, given the reduced cross-sectional area, a fracture is most likely to occur at this site.

HPI

The patient reports that during routine daily exercise, he jumped over a fence, tripped, and landed on his chin and right hand. He was seen at a local emergency department for the deep laceration on his chin. He also complains of inability to open wide and pain in front of his right ear. The patient did not lose consciousness, and no bleeding from the ear canal, auditory dysfunction, dizziness, tinnitus, nausea/vomiting, or visual changes are present. There is no dyspnea, stridor, or inability to manage secretions. The patient states that he is unable to get the teeth to interdigitate, he has reduced ability to open the mouth, and he feels intense pain when attempting excursive movements. There are no neurosensory changes in the lip, chin, tongue, or midface.

A thorough review of systems is essential when evaluating these patients, as is ensuring appropriate advanced trauma life support (ATLS) evaluation. Traumatic force to the mandible is transmitted to the skull base. A review of symptoms related to intracranial injury and closed head injury, as mentioned previously, allows the surgeon to determine additional studies, evaluations, or referrals. The surgeon must also be diligent about investigating signs of cervical injury; the association between mandibular fractures and cervical spine injuries is well established (although these two types of injuries infrequently occur together), and any neck pain warrants further evaluation. In addition, the surgeon must evaluate for signs of concomitant mandibular fractures, because more than half of fractures are associated with contralateral parasymphysis or body/angle fracture. A significant impact to the chin, as occurred in the current patient, raises concern for bilateral subcondylar fracture with the potential for airway compromise; therefore, a review of symptoms related to airway obstruction must be performed.

PMHX/PDHX/Medications/Allergies/SH/FH

Noncontributory.

Examination

General. The patient is a well-developed and well-nourished man in no apparent distress.

Maxillofacial. There is a 3-cm hemostatic laceration at the submental region with no foreign body or signs of obvious fracture. Upon opening, the mandible deviates to the right (due to the unopposed contralateral lateral pterygoid muscle and impaired rotation and translation on the affected side). The maximal interincisal opening is limited to 20 mm, with associated pain. There is edema of the right preauricular region, no deformity of the ear, no blood at the external auditory canal (EAC), no hemotympanum, and normal auditory acuity (hemotympanum and blood at the EAC may indicate perforation of the anterior tympanic plate). There is no otorrhea or Battle's sign (which may indicate basilar skull fracture and CSF leakage). Palpation of the right preauricular region also elicits pain (pain in the preauricular area with a history of trauma to the symphysis is highly suggestive of a subcondylar fracture).

Intraoral. Left lateral excursive movement is limited to 2 mm (excursive movement of the mandible to the left requires the function of the right lateral pterygoid against an intact condylar neck). There are no associated intraoral lacerations and no dental trauma (fractures of the teeth are not uncommon with forceful closure of the mandible at the time of trauma). Occlusal examination shows premature contacts on the right side, with a posterior left open bite (secondary to collapse of the vertical height of the mandible on the right). The airway is patent with no obstruction or reduction in airflow.

Extremities. There is pain to passive range of motion (ROM) of the right wrist. A palpable radial pulse and normal capillary refill in the nail beds are present (vascular compromise from a distal radial fracture or a carpal bone fracture, or in a compartment system, is a surgical emergency).

Imaging

Depending on the facility, initial imaging for evaluation of the mandible may include a computed tomography (CT) scan, cone-beam CT scan, panoramic radiograph, or plain view mandibular series that includes lateral and posteroanterior cephalometric films, a reverse Towne's view, and oblique views of the mandible. Many rural hospitals still use a plain view series of the mandible. Most hospitals use a CT scan, which has become the gold standard imaging modality. A CT scan allows the entire face to be evaluated in one study. The mandible can also be evaluated in several different anatomic planes. The axial and coronal planes are the two most commonly used views. The coronal plane can be very helpful for condylar process fractures and for determining dislocation and orientation; the axial planes are useful for intracapsular fractures and the remainder of the mandible. Direct coronal imaging requires hyperextension of the neck and should not be obtained in patients with a suspicion of cervical spine injury. Three-dimensional reconstructions are extremely valuable and allow preoperative planning in a more sophisticated manner for complex cases such as gunshot wounds or severely comminuted fractures. A panoramic film is the single best plain film for evaluating the entire mandible at once. In combination with a reverse Towne's view, the sensitivity for detecting a condylar process fracture increases. However, all modalities have limitations, and surgeons should use imaging studies based on individual cases and available resources.

For the current patient, a CT scan was obtained as the initial study. It demonstrated a right subcondylar fracture on coronal and axial views ( Figure 8-5 ). A plain wrist film was also obtained, which revealed a right-sided fracture of the distal radius (Colles fracture).

Labs

No routine laboratory testing is indicated unless dictated by the medical history.

Assessment

Right subcondylar fracture of the mandible and associated chin laceration; Colles fracture of the right wrist; FISS score of 1.

Treatment

The treatment of fractures of the mandibular condyle is one of the most widely debated topics in the maxillofacial literature. Several variables should be considered when determining treatment and predicting the prognosis, including the level of fracture, degree and direction of displacement, age and medical status of the patient, concomitant injuries, and status of the dentition. Assael has developed a comprehensive list of considerations affecting treatment selection and outcome, all of which should be included in the evaluation of the patient prior to the institution of therapy. Although comprehensive discussion of these considerations is beyond the scope of this chapter, the variables can be divided into patient, surgeon, and third-party categories. Age, gender, medical status, compliance, associated injuries, and fracture type are a few of the patient-specific variables. The surgeon's ability and resources, in addition to resources to cover the expense of treatment, are also pertinent to successful treatment.

The primary goal in the treatment of any fracture is adequate stabilization that allows for fracture healing and primary osseous union. In the treatment of mandibular condyle fractures, the goals of treatment are:

• Pain-free mouth opening with return to an acceptable interincisal opening

• Pain-free functional movement

• Restoration of occlusion

• Facial and jaw symmetry and establishment of facial height

• Minimal visible scarring

Preinjury alignment of the mandibular condyle within the glenoid fossa is not essential for adequate rehabilitation after mandibular condyle fractures. The pull of the lateral pterygoid muscle characteristically displaces the condyle anteriorly and medially; therefore, closed reduction (more correctly termed “closed treatment”) typically does not reduce the condyle into its original position.

The treatment options are categorized into surgical and nonsurgical modalities. Surgical treatment includes open reduction with or without internal fixation; however, most agree that if an open approach is taken, fixation should be applied. Endoscopic reduction and fixation of condylar fractures has gained popularity during the past decade. The use of this technique requires familiarity with the endoscope and the ability to convert the procedure to an open method if endoscopic reduction fails to successfully complete the procedure. The options for nonsurgical treatment include closed reduction (closed treatment) with maxillomandibular fixation (CR-MMF) and dietary modification with ROM exercises. In the treatment of facial fractures, patients older than 10 years are treated in a manner similar to that for adults; however, it is rarely advocated that children and teenagers undergo open reduction of condylar fractures. A soft diet with mobilization is the treatment of choice in patients 15 years old or younger. If the occlusion is unstable and not reproducible, a short period of intermaxillary fixation (2 weeks) can be advocated.

For the current patient, the occlusion was reestablished easily with minimal manipulation, and after extensive discussion of procedures, alternatives, risks, and benefits, the patient was placed in maxillomandibular fixation (MMF) for 4 weeks, After the 4 weeks, an aggressive post-treatment physiotherapy program was instituted, with active and passive range of motion exercises. Return to full function occurred within 4 weeks of release from MMF. There were no postoperative complications and, the patient returned to full function with stable and repeatable occlusion.

Complications

The complications of treating fractures of the mandibular condyle are well described in the literature and are often used as the basis of comparison for surgical and nonsurgical treatment. One of the most severe late complications can be temporomandibular joint (TMJ) ankylosis (fusion between the mandibular condyle and the glenoid fossa). Patients with TMJ ankylosis often have a history of facial trauma. Prevention of ankylosis was discussed by . They advocated appropriate physiotherapy early in the phase of nonsurgical treatment. Other types of late mandibular dysfunction have been cited as complications of closed reduction, including chronic pain, malocclusion, internal derangement, asymmetry, limited mobility, and gross radiographic abnormalities (however, radiographic abnormalities in the absence of pain or functional impairment have no clinical significance). Long-term complications of open reduction and internal fixation (ORIF) are scar perception, facial nerve palsy/paralysis, loss or failure of fixation, Frey's syndrome, avascular necrosis, TMJ dysfunction, and facial asymmetry. The early complications are few and can include early failure of fixation, malocclusion, pain, and infection.

Discussion

As is common with most traumatic injuries, fractures of the mandibular condyle occur in men (78%) between the ages of 20 and 39 (60%). The majority of the fractures are unilateral (84%); fewer are bilateral (16%); 14% of fractures are intracapsular, 24% are in the condylar neck, and 62% are subcondylar fractures. Adults have a relatively narrow condylar neck and thick articular surface, whereas the pediatric patient has a relatively broad condylar neck and thin articular surface in an active osteogenic phase (pediatric fractures are discussed later in the chapter).

Many studies have compared various outcomes of surgical and nonsurgical therapy, with most of the debate centering on ORIF and CR-MMF (closed treatment). The outcomes studied included perception of pain, occlusal function, asymmetry, maximal interincisal opening/ROM, muscle activity, malocclusion, midline deviation, radiographic changes, and nerve dysfunction. conducted a review of the literature ( Table 8-1 ) regarding open versus closed treatment and suggested indications for closed and open reduction. If a patient has an acceptable ROM, good occlusion, and minimal pain, observation or CR-MMF is preferred, regardless of the level of the fracture. They also suggested that condylar displacement and ramus height instability are the only orthopedic indications for ORIF of condylar fractures. Based on their review, they concluded that under similar indications and conditions, ORIF is the preferred approach. In developed a method for determining which patients would not benefit from ORIF using preoperative imaging and intraoperative clinical evaluation. This method demonstrated that patients with fractures that did not easily drop back into a malocclusion with digital pressure would not require either open reduction and can be treated with elastics to attain an acceptable occlusion.

Haug and Assael described the indications and contraindications for open treatment of condylar fractures in 2001. Their absolute indications for ORIF are patient preference (when no absolute or relative contraindications coexist); cases in which manipulation and closed reduction cannot reestablish pretraumatic occlusion and/or excursion; cases in which rigid internal fixation is used to address other fractures, affecting the occlusion; the rare instance of intracranial impaction of the proximal condylar segment; and cases in which stability of the occlusion is limited. Among the absolute contraindications are condylar head fractures (including single fragment, comminuted, and medial pole) and patients in whom medical illness or systemic injury adds undo risk to an extended general anesthesia. Condylar neck fractures were among the relative contraindications.

With nonsurgical techniques, there is no consensus on the use or duration of immobilization. Literature is available supporting anywhere from 0 to 6 weeks of closed treatment. A period of MMF is typically instituted for one of three reasons:

• 1.

  Patient comfort

• 2.

  To promote osseous union and restore premorbid occlusion

• 3.

  To help reduce the fractured segment

One method for treating fractures with no occlusal disturbances, acceptable ROM, and minimal pain is to place the patient in early full function, along with functional physiotherapy. If the patient demonstrates occlusal discrepancy, Erich arch bars can be placed for MMF or guiding elastics. For pediatric patients in a mixed dentition stage who demonstrate an occlusal discrepancy, there may be a need for circummandibular wires and/or circumzygomatic or piriform wires to obtain adequate stabilization.

Regardless of the type of treatment, patients should undergo postoperative physical therapy. Functional therapy is needed to improve ROM, asymmetric movements, scarring within the joint, or other TMJ dysfunctions. If there is limitation in mouth opening, tongue blades or other sequentially enlarging devices to gradually improve the range of mandibular opening can be used. For patients with asymmetric mouth opening, it is recommended that they function on the contralateral side. Patients can be encouraged to observe their opening and closing in the mirror and to use their hand to help correct any asymmetric movement. The overall goal is to achieve early full function and restoration to symmetric, pain-free mandibular motion.

When the decision is made to use ORIF, many advocate a retromandibular approach. This approach affords excellent exposure to the ramus-condyle unit for reduction and fixation. The approach was first described by and later adapted for use in the treatment of mandibular condylar fractures. An incision of 3 cm is made parallel to the posterior border of the mandible starting 1 cm below the earlobe. Dissection proceeds through skin, subcutaneous tissue, and platysma down to the parotid capsule. The tail of the parotid is released and elevated with blunt dissection, if necessary, to avoid violation of the parotid capsule. The posterior mandible and pterygomasseteric sling are identified. The periosteum at the posterior border of the mandible is incised and dissected in a subperiosteal plane. Both sides of the fracture are exposed to facilitate reduction and fixation. A similar approach can be used with endoscopy. This approach allows excellent exposure to the ramus-condyle unit, minimal visible scarring, and a low incidence of facial nerve damage. Other surgical approaches to the mandibular condyle include a preauricular (or endaural) incision, intraoral incision, or Risdon-type incision, depending on the fracture pattern and location.

Multiple modalities have been used to rigidly fix mandibular condylar fractures. Studies have evaluated the biomechanical behavior of dynamic compression plates, locking plates, mini–dynamic compression plates, adaptation plates, and single and double miniplates. Both mini–dynamic compression plates and double miniplates have been shown to be stable for fixation. It has also been shown that resorbable plates are effective and provide reliable stability in ORIF of condylar fractures. Many surgeons recommend that fixation be applied with the use of one or two 2-mm plates with two or three bicortical screws on both sides of the fracture. Lag screw fixation can be used in appropriate situations ( Figure 8-6 ).

As is true for most conditions, the treatment of pediatric patients requires special consideration. Up to 40% of mandibular fractures in pediatric patients involve the condyle. Anatomically, pediatric patients have a relatively broad condylar neck and a thin articular surface; this accounts for the fact that 41% of the fractures are intracapsular. Clinical suspicion and accurate diagnosis are crucial in the early stages, because missed or delayed diagnosis may not be apparent until further growth leads to morphologic or occlusal disturbance. Because pediatric patients are often in the mixed dentition stage, occlusal changes may not be as readily detected. Imaging of children is of particular concern; panoramic imaging is useful, but coronal CT has been found to be highly diagnostic in the pediatric population. Historically, nonsurgical treatment of condylar fractures has involved MMF followed by physiotherapy; given the greater osteogenic potential and faster healing rates in children than in adults, the duration of MMF has been decreasing over time and often is not even used. We recommend that a soft diet, aggressive physiotherapy, and growth monitoring be used and that closed treatment be reserved for open bite or malocclusion. Although many are proponents of open reduction even in a pediatric population, there is little role for this treatment modality, and no functional benefit has been shown. Growth disturbance has been associated with pediatric condylar fractures, and growth surveillance should be provided for all patients with these injuries.

CC

You are asked by the trauma physician at your local emergency department (ED) to evaluate a 23-year-old male patient for facial fractures (mandibular fractures are more common in males in the third decade of life). His chief complaint is, “My jaw hurts, and my teeth do not come together like before.”

HPI

The patient was riding his motocross bike earlier today when he crashed and landed on his face. He was not wearing a helmet; however, he denies any loss of consciousness. He was able to get up from the scene and ride his bike to the ED. He explains that his lower face and jaw are painful, his teeth do not occlude correctly, and his left lip is anesthetic.

Assault, motor vehicle accidents, and sporting injuries are the most common etiologies of mandibular fractures. Malocclusion is the single most important historic information suggestive of a mandibular or dentoalveolar fracture. Paresthesia of the distribution of the third division of the trigeminal nerve (V3) is common and can be due to neuropraxia, axonotmesis, or neurotmesis of the mental or inferior alveolar nerve at the fracture site.

PMHX/PDHX/Medications/Allergies/SH/FH

The patient smokes one pack of cigarettes a day and drinks alcohol on the weekends. He denies all other habits (both alcohol and tobacco use have been associated with an increased risk of infectious complications with mandibular fractures).

Examination

Imaging

Most practitioners consider computed tomography (CT) scans to be the gold standard imaging modality for evaluation of mandibular fractures. A CT scan allows the entire face to be evaluated in one study. Facial bones, including the mandible, can be evaluated in several different anatomic planes. The axial and coronal planes are the two most commonly used views. The coronal plane can be very helpful for condylar process fractures, whereas the axial views are useful for the corpus. Patients with suspicion of cervical spine injury should not have the neck hyperextended for direct coronal imaging. Instead. digitally reconstructed coronal images can be used.

Despite the popularity of CT imaging, in many facilities the initial imaging studies may consist of a panoramic radiograph or a plain view series of the mandible (posterior-anterior, reverse Towne's, bilateral lateral oblique radiographs). Many hospitals still use a plain view series of the mandible; therefore, familiarity with plain radiographs is important.

A panoramic radiograph is the imaging modality of choice for patients presenting at the surgeon's office. This radiograph is inexpensive and is the single best plain film for evaluation of the entire mandible. However, nondisplaced or minimally displaced fractures of the condyle or the symphyseal area may be difficult to detect on a panoramic radiograph. The combination of a reverse Towne's view and an anterior-posterior radiograph of the mandible results in a sensitivity and specificity similar to that of a CT scan. The decision to order different imaging modalities should be based on available resources, physical exam findings, and the cost and knowledge of limitations related to particular studies. When available, in-office cone-beam CT scans are excellent for evaluating mandibular fractures.

For the current patient, a panoramic radiograph demonstrates fractures at the left angle and in the right parasymphysis area ( Figure 8-7, A ) . A anterior-posterior view of the mandible shows severe displacement at the left angle (which explains the anesthesia of the left V3) and fracture at the right parasymphysis ( Figure 8-7, B ); note that the degree of lateral displacement is not evident on the panoramic radiograph.

Labs

Routine laboratory testing is not mandatory prior to surgical correction of mandibular fractures unless dictated by underlying medical conditions. In cases of infected mandibular fractures, a white blood cell count should be obtained.

Assessment

Open mandibular fractures at the right parasymphysis (nondisplaced), and left angle (severely displaced). Facial Injury Severity Scale (FISS) score of 4. Also, an associated injury to the left inferior alveolar nerve most consistent with neurotmesis or a Sunderland's class 5 injury.

Treatment

The treatment of mandibular fractures has a long and complicated history, dating back to 1600 b . c . The mandible is unique in that it is singled out as the bone in the face requiring special attention for various aspects of treatment (occlusion, esthetics, function) to achieve a good result. The important points in treating mandibular fractures are immobilizing fractures, appropriate use of antibiotics, and restoration of form and function.

Mandibular fractures at the angle and parasymphysis involving the teeth-bearing segments are considered open fractures. Treatment should be rendered in a timely fashion, as soon as the patient is stable and operating room facilities are available. Preoperative antibiotics have been shown to decrease the incidence of postoperative infectious complications and should be initiated regardless of the time interval before definitive surgery can be completed. The use of postoperative antibiotics remains largely practitioner dependent, and no good evidence exists guiding its necessity and potential benefits or the duration of treatment.

More important in the prevention of infection is the proper application of fixation. Movement at the fracture site increases not only the chance of infection but also the development of fibrous union, malunion, or nonunion. Rigid fixation is the key to a good outcome. However, semirigid fixation techniques, when correctly applied, can also provide a successful outcome. In addition, lag screws are a strong form of fixation and provide very good rigidity; however, the technique is not applicable to all fractures. Locking (rather than nonlocking) fixation plates provide continued rigidity if the contact area at the screw or plate–to–bone interface is reduced due to bony remodeling. In addition, locking plates do not require precise adaptation to the bony anatomy, because the screw is “locked” into special threads in the plate. Closed reduction of mandibular fractures continues to be an acceptable form of treatment and in certain patients is the best option. Closed reduction does not offer the benefit of early function, and the patient must tolerate a prolonged period of intermaxillary fixation.

If the mandible has more than one fracture, consideration should be given to the sequence of fixation. It is generally advocated to fixate the fracture segments involving dentate segments, to ensure correct occlusal relationship, prior to fixation of nondentate segments. In the current patient, the parasymphysis facture was repaired first to correctly establish arch form and occlusion.

The patient was treated with open reduction and rigid internal fixation (ORIF) under general anesthesia in an ambulatory care facility ( Figure 8-8 ). Arch bars were applied, and subsequently the occlusion and arch form were reestablished. Fixation at the parasymphysis fracture was completed by placing a plate at the superior border (zone of tension) and a plate at the inferior border (zone of compression). The fracture at the angle was reduced and fixated using rigid fixation plates at the superior and inferior borders. No postoperative maxillomandibular fixation (MMF) was used. The patient was allowed to function and maintain a soft-chew diet. The use of antibiotics consisted of perioperative intravenous penicillin. The patient was sent home with a prescription for Peridex and oral analgesics. The postoperative course was otherwise uncomplicated.

This type of fracture can also be treated using a single lag screw placed according to the Niederdellman method ( Figure 8-9 ) .

Complications

Mandibular angle fractures are generally more prone to the development of complications compared with the body, symphyseal, or parasymphyseal areas. Multiple complications may arise, but the most common are loose hardware, necessitating removal; infection; malocclusion; delayed union; and fibrous union. Damage to the inferior alveolar and lingual nerves can be a complication of the initial injury or a consequence of treatment. Infection rates for angle fractures reportedly range from 2% to more than 19%.

Discussion

There is a variety of options for the treatment of mandibular fractures, and these options primarily differ in the method of fixation (number, size, and location of fixation plates and screws). Traditionally, mandibular fractures have been successfully treated with closed reduction using intermaxillary fixation. This method results in relatively few complications. However, it is associated with a delay in functional rehabilitation compared with the more modern ORIF techniques.

Open reduction and internal fixation failed to attain widespread use prior to the 1960s mainly due to early reports of metal corrosion of steel plates and screws, metal fatigue, and screw loosening. The advent of biocompatible materials (e.g., Vitallium and titanium), along with orthopedic biomechanical studies describing the benefits of compression osteosynthesis, increased interest in open treatment of mandibular fractures. Today many practitioners prefer open to closed reduction of parasymphysis/angle fractures of the mandible. The treatment of subcondylar fractures has caused a series of controversies that are addressed in a separate chapter.

Considerable variation is seen when methods of fixation are compared. For example, dynamic compression plating (Schmoker and Spiessl), monocortical noncompression miniplate (Michelet), superior border mandibular angle plate (Champy) ( Figure 8-10 ), lag screw (Niederdellmann and colleagues), and rigid locking reconstruction plate techniques have all been described in the literature. Consensus on the optimal treatment of mandibular parasymphysis/angle fractures remains elusive; each method has its pros and cons, and few prospective, randomized trials have been done for direct comparison.

Angle fractures produce the highest frequency of complications among mandibular fractures. Infection, malunion, nonunion, and damage to adjacent structures (nerve, tooth) all plague reduction of this anatomic site. Thus many practitioners advocate absolute rigidity of the bony segments for rapid, uncomplicated healing. Early on, the Arbeits-gemeinschaft für Osteosynthesefragen /Association for the Study of Internal Fixation (AO/ASIF) established principles recommending superior and inferior border dynamic compression plates. On the other end of the spectrum, Champy recommended a single noncompression miniplate at the superior border for angle fractures, based on his studies demonstrating the tendency of the superior border to separate from unfavorable muscle pull (tension zone) and the inferior mandibular border to compress (compression zone), with an interposed neutral zone or “line of zero force.” Contrary to the principles of interfragment rigidity for optimal healing, some studies describe decreased complications with less rigid techniques, such as the Champy technique.

Niederdellmann in the 1970s described the use of lag screws for the treatment of mandibular angle fractures, with placement of the screw through the impacted third molar, if present, and subsequent removal of the tooth and screw after healing. Due to technique sensitivity and difficulty, the Niederdellmann lag screw technique remains less popular.

Several studies have found an increased risk of angle fractures associated with the presence of impacted third molars. Management of teeth in the line of fracture had previously sparked some controversy. Extraction is undoubtedly indicated when the tooth in the line of fracture is deeply carious, harbors periodontal or pericoronal infection, prevents bony reduction of the fracture, demonstrates severe root exposure, or is fractured. However, in the absence of these conditions, extraction of the tooth has not been shown to have a statistically significant benefit. Ellis reported a relatively increased, but statistically not significant, risk of postoperative complications (namely, infection) with teeth left in the line of fracture, resulting in the need for infection management and/or removal of hardware. Other studies recommend that tooth buds in the line of fracture be preserved unless infection occurs, requiring subsequent removal.

Overall, mandibular angle fractures are common and relatively easily treated with a variety of conventional techniques. The surgeon should keep in mind the potential complications and adhere strictly to sound principles of treatment, regardless of the technique selected.

CC

A 28-year-old (peak incidence is in the second or third decade) man (male to female ratio is 4 : 1) is admitted to the local emergency department 4 hours after he was hit on the left side of the face with a fist (left zygoma is most commonly affected). He complains of left-sided facial pain, blurry vision, and inability to open his mouth fully (trismus is present in about one third of patients).

HPI

The patient claims that he was minding his own business when he was suddenly “jumped” and punched in the face by an unknown individual. He does not report losing consciousness. He was subsequently brought to the emergency department by the emergency medical services (EMS) personnel.

PMHX/PDHX/Medications/Allergies/SH/FH

The patient has a positive history of alcohol abuse (more common in the trauma population) and an 8 pack-year history of tobacco use.

Examination

The patient's advanced trauma life support (ATLS) primary survey is negative, and his Glasgow Coma Scale (GCS) score is 15.

General. The patient is alert and oriented × 3. He is a well-developed and well-nourished man in mild distress.

Vital signs. His blood pressure is 130/84 mm Hg, heart rate 120 bpm (tachycardia), respirations 16 per minute, and temperature 37.6°C.

Maxillofacial. There is tenderness over the left zygoma and subconjunctival ecchymoses and edema around the left eye (present in 50% to 70% of cases). There is a palpable step along the zygomaticofrontal (ZF) suture and infraorbital rim, with flattening over the zygomatic arch, in addition to visible depression over the malar eminence and hypoesthesia of the left maxillary branch (V2) of the trigeminal nerve (50% to 90% of cases).

Eyes. The pupils are equal, round, and reactive to light and accommodation (PERRLA) (cranial nerves II and III), with no ptosis (cranial nerve III). There is no proptosis (tense proptosis may be indicative of a retrobulbar hematoma, a surgical emergency). Careful examination of the pupils reveals a downward displacement of the left pupil suggestive of loss of osseous support along the orbital floor and/or an increase in orbital volume. The lateral palpebral fissure appears grossly displaced inferolaterally (producing an antimongoloid slant). Examination of the extraocular muscles demonstrates a decrease in range of motion in the extremes of upward and downward gaze (mostly due to edema). Visual fields are intact by confrontation (cranial nerve II). Examination of the left eye confirms binocular diplopia (10% to 40% of cases). Visual acuity is 20/25 bilaterally (cranial nerve II); there is no hyphema (blood in the anterior chamber of the eye); and the fundoscopic examination is within normal limits.

Intraoral. There is ecchymosis of the maxillary buccal sulcus on the left.

Imaging

The CT scan (bony windows) is the gold standard for evaluation of zygomatic fractures, using axial and coronal sections. Reconstructed parasagittal views through the orbit can be valuable for assessing the orbital floor in the anteroposterior dimension. Direct coronal imaging may not be feasible, given the status of the cervical spine in the acute setting.

In the current patient, axial sections ( Figure 8-11, A ) reveal a significantly displaced left zygoma with fractures at the anterior maxillary wall and zygomaticotemporal (ZT) and zygomaticosphenoid (ZS) sutures. Coronal CT ( Figure 8-11, B ) reveals fractures at the right ZF suture and zygomaticomaxillary (ZM) buttress and disruption of the left orbital floor with displacement of orbital contents into the maxillary sinus. A three-dimensional computer reconstruction, although not necessary, can also be helpful in treatment planning ( Figure 8-11, C ).

Three-dimensional reconstructed CT or cone-beam computed tomography (CBCT) scans can also be most valuable in the diagnosis and visualization of ZMC fractures. Figure 8-12 demonstrates a more severe comminuted and displaced orbito-ZMC fracture.

Labs

No routine laboratory testing is necessary for the management of isolated zygomaticomaxillary complex (ZMC) fractures unless dictated by the medical history. A blood alcohol level and urine drug screen should be obtained in cases of suspected alcohol or drug intoxication.

The current patient had a blood alcohol level of 150 mg/dl (alcohol is commonly implicated in the trauma population) and a negative urine drug screen.

Assessment

Isolated fracture of the left ZMC; FISS score of 1.

Treatment

The goal of treatment is reduction of the fracture to its anatomic position to achieve optimal functional and aesthetic rehabilitation. The ZS is not commonly fixated, but adequate reduction at this suture is a good indicator of the overall three-dimensional position of the zygoma. The degree of displacement and comminution, the age of the patient, and preexisting skin creases or lacerations, in addition to the status of the globe, should be taken into account for surgical treatment planning. As with any surgery, the best treatment is that which achieves the best outcome with the least intervention. Extensive dissection and plating at multiple sutures may provide a very stable zygoma, yet the anatomic demands on the zygoma may be equally met with more conservative approaches in select cases. In a study by Zachariades and colleagues, 1,270 patients with ZMC fractures were reviewed; the researchers concluded that the best results are achieved with semirigid fixation with miniplates at one or more sites.

The current patient was taken to the operating room for open reduction with internal fixation (ORIF). Fixation was used at the ZF suture via an upper blepharoplasty (supratarsal fold) incision and at the maxillary buttress via the maxillary buccal vestibular approach. The zygomatic arch was reduced via the same incision using a Goldman elevator. Subsequently, the orbital floor and rim were explored and reconstructed via the transconjunctival approach using a titanium mesh and plate. A bilateral forced duction test was performed at beginning and the completion of the procedure.

CT-guided intraoperative navigation has gained some role in the treatment of complex midfacial fractures. This allows three-dimensional intraoperative visualization of the anatomy, for more accurate reconstruction, especially when multiple comminuted fragments complicate the stable landmarks for reduction. The patient in Figure 8-12 was treated using CT-guided intraoperative navigation and subsequent anatomic reduction ( Figure 8-13 ).

Complications

Complications of ORIF of ZMC fractures can be divided into functional and aesthetic categories, which can be related to the surgical approach. The most feared, but fortunately rare, complication is blindness secondary to retrobulbar hemorrhage (0.3%). Retrobulbar hematoma may present as tense proptosis, eye pain, elevated intraocular pressures, and visual disturbances (decreased red-green color perception, followed by decreased visual acuity) that may require surgical decompression via a lateral canthotomy and inferior cantholysis. The initial trauma also may irreversibly affect the vision. Orbital complications, such as ectropion and enophthalmos, can be a significant concern to the patient and the surgeon. The incidence of ectropion after a subciliary incision varies considerably in the literature. However, most series have reported a greater incidence of ectropion with this incision compared with the transconjunctival approaches. A great majority of cases of ectropion are transient and resolve with nonsurgical interventions.

Enophthalmos can be a difficult aesthetic problem to correct and predict. Our ability to predict the incidence of enophthalmos (based on clinical and radiographic parameters) is a key measure in determining the need for orbital floor exploration. This is weighed against the aesthetic and functional risks to the eye and periorbital tissue from orbital floor exploration and reconstruction. It is unclear what amount of orbital floor disruption would predictably cause enophthalmos. However, it is generally accepted that disruption of more than 50% of the floor, along with loss of support at the equator of the globe, causes future enophthalmos if left untreated. Therefore, careful consideration must be given to orbital floor exploration in treatment planning.

Dysfunction of the infraorbital nerve is common and intuitively related to the severity of the initial trauma, the status of the nerve, and the complexity of dissection and stretching of the soft tissue. Persistent diplopia is uncommon, because most cases of binocular diplopia resolve after the resolution of edema; however, persistent diplopia beyond 7 days requires further investigation to rule out inferior rectus entrapment.

It is important to distinguish between monocular diplopia (double vision with the unaffected eye closed) and binocular diplopia (double vision with both eyes open). Monocular diplopia may be caused by trauma to the globe, such as lens dislocation or retinal detachments. This requires emergent ophthalmologic consultation. Binocular diplopia (which is far more common) is generally caused by extraocular muscle dysfunction secondary to edema or entrapment or globe malposition.

Aesthetic complications, such as hypertrophic scars and inadequate bony reduction, can be addressed surgically at the appropriate time.

Discussion

An understanding of the anatomy of the zygoma is essential in the treatment of ZMC fractures. By definition, the four articulating sutures (ZF, ZT, ZM, and ZS) are disrupted in this fracture. Therefore, the commonly applied term “tripod fracture” is a misnomer and does not correctly describe this fracture.

Much controversy exists regarding the optimal treatment of ZMC fractures. Not unlike any other condition, treatment needs to be individually tailored to both the patient and the surgeon's experience. In the preoperative evaluation of the patient with a ZMC fracture, the ophthalmologic examination is of paramount importance. An ophthalmology consultation should be obtained on select cases as dictated by the physical examination findings.

Another area of controversy is the amount of fixation necessary for adequate reduction (ranging from none to four-point fixation). The ZF and ZM sutures are the most commonly fixated areas. All ZMC fractures involve the orbital floor (composed of the orbital segment of the maxilla, zygomatic bone, and orbital process of the palatine bone). However, as mentioned, not all ZMC fractures warrant orbital floor exploration and reconstruction. Entrapment of the extraocular muscles warrants orbital floor exploration. On evaluation of the eye, however, the examiner should be careful to distinguish impaired extraocular movement secondary to generalized edema, which is very common and frequently impairs all directions of gaze, from inferior rectus entrapment, which is rare and usually demonstrates strict impairment of upward gaze.

CC

A 33-year-old man presents to the emergency department complaining of left facial swelling, pain, and difficulty opening his mouth.

The epidemiology of isolated midfacial fracture varies greatly, depending on the geographic region, population density, socioeconomic status, and type of facility in which the research was conducted. Generally, an increased incidence is seen in the third decade of life and over the age of 50. Primary mechanisms of injury are interpersonal violence and motor vehicle collisions in the younger population and falls in the older population. A preponderance of left-sided injuries is seen when the etiology involves a personal altercation, because most assailants are right-handed and use this hand to strike the opponent on the left side.