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Fracture, Mandibular

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Fracture, Mandibular
Harry Stafford
Blake Boggess
Basics
  • First priority is to protect the airway, as severe fractures of facial structures may result in airway obstruction from lack of glossal-supporting structures, blood clots, loose teeth, dentures, or bony fragments.
  • Protect the C-spine.
Description
  • Fracture of the mandible is usually due to a direct force.
  • Frequently injured because of the mandible's prominence and relative lack of support
  • The most common area to be fractured is the angle, followed by the condyle, molar, and mental regions.
  • Because of its thickness, the mandibular symphysis is rarely fractured.
Epidemiology
The mandible is the third most common facial fracture following nasal and zygomatic fractures.
Incidence
The incidence of mandibular fractures is lowest in children younger than 5 yrs of age (1.2 per 100,000), and peaks between 16 and 20 yrs of age (26.5 per 100,000).
Prevalence
Fractures of the mandible have been reported to account for 36–70% of all maxillofacial fractures.
Risk Factors
43% of mandible fractures are caused by vehicular accidents, 34% by assaults, 7% work-related, 7% the result of a fall, 4% from sporting accidents, and the remainder were unspecified (1).
Etiology
  • Usually result from a direct force applied to the mandible by motor vehicle accidents, personal violence, contact sports, or industrial accidents
  • The most common area to be fractured is the angle, followed by the condyle, molar, and mental regions.
Commonly Associated Conditions
  • Additional traumatic facial fractures and other injuries
  • Patients may be intoxicated and unable to give a complete history of the injury.
Diagnosis
History
  • The source, size, and direction of traumatic force are helpful in diagnosis.
  • Patients involved in motor vehicle accidents tend to sustain compound, comminuted fractures.
  • Localized trauma (eg, pipe, stick, hammer, fist) tends to cause a single comminuted fracture since the force is concentrated in a small area.
  • Trauma distributed to a larger surface area may cause several fractures (eg, symphysis, condyle) secondary to distribution of the force throughout the mandible. These fractures are classified by the anatomic location. More than 50% of patients have multiple fractures.
  • Direction of the force can help in making the diagnosis of concomitant fractures. Trauma directed to the chin often results in a symphyseal fracture with concomitant unilateral or bilateral condylar fractures.
Physical Exam
  • Patient complaints include:
    • Facial asymmetry, deformity, dysphagia, and mandibular pain
    • Malocclusion, decreased range of motion of the temporomandibular joint, or a grating sound conducted to the ear with movement of the mandible
  • Inspect the maxillofacial area for obvious deformity:
    • Note facial lacerations, swelling, and hematomas.
    • A common site for a laceration is under the chin, and is associated with subcondylar or symphysis fracture.
  • From behind the supine or seated patient, bimanually palpate the inferior border of the mandible from the symphysis to the angle on each side. Note areas of swelling, step deformity, or tenderness.
  • Loose, fractured, or missing teeth, gross malalignment of teeth; separation of tooth interspaces; and ecchymosis or hematoma of the floor of the mouth
  • Protrusion or lateral excursion of the jaw. Interference with normal mandibular function, including decreased range of motion or deviation of the mandible with opening:
    • The examiner should be able to insert 3 fingers between the mandible and maxilla.
    • Suggested by inability of the patient to break a tongue depressor placed between the teeth and forced downward
  • Paresthesia of the lower lip or gums strongly indicates a mandibular fracture with secondary damage to the inferior alveolar nerve.
  • Standing in front of the patient, palpate the movement of the condyle through the external auditory meatus. Pain elicited through palpation of the preauricular region should alert the clinician to a possible condylar fracture.
  • Observe any deviation on opening of the mouth, or for an inability to chew or open mouth:
    • Deviation on opening is typically toward the side of the mandibular condyle fracture.
    • Note any limited opening and trismus that may be a result of reflex muscle spasm, temporomandibular effusion, or mechanical obstruction to the coronoid process resulting from depression of the zygomatic bone or arch.
  • Changes in occlusion are highly suggestive of a mandibular fracture.
  • Look for intraoral mucosal or gingival tears:
    • Floor of the mouth ecchymosis may indicate a mandibular body or symphyseal fracture. If a fracture site along the mandible is suggested, grasp the mandible on each side of the suspected site and gently manipulate it to assess mobility.
  • Inability of the examiner to note motion of the mandibular condyles when palpated through the external ear canals with motion of the jaw is highly suggestive of a mandibular fracture.
Diagnostic Tests & Interpretation
Imaging
  • The following types of radiographs are helpful in diagnosis of mandibular fractures:
  • Panoramic radiograph
  • Bilateral oblique radiographs
  • Posteroanterior mandibular view
  • Reverse Towne view
  • Mandibular occlusal view
  • Mandibular views are best for evaluating the condyles and neck of the mandible.
  • Dental panoramic views are best for evaluating the symphysis and body.
Diagnostic Procedures/Surgery
If the plain films are negative and a condylar fracture is still suspected, obtain a CT of the condyles in the coronal plane.
Differential Diagnosis
  • Contusions
  • Dislocation of the mandible
  • Isolated dental trauma
Treatment
Pediatric Considerations
  • Mandibular fractures are uncommon in children <6 yrs of age. When they do occur, they are usually greenstick fractures and can be managed with soft diet alone. Parents should be informed that any fracture of the mandible has the potential to damage permanent teeth and cause facial asymmetry; long-term follow-up with a specialist is advisable.
  • 20–40% of patients have associated injuries, and treatment should address the most lethal concerns from airway obstruction, aspiration, major hemorrhage, cervical spine or cord injury, and/or intracranial injury.
  • Airway compromise can occur from intraoral edema and hematoma, bony fragments, loose teeth, and loss of tongue support.
  • C-spine precautions should be maintained.
  • If intubation is needed, an oral trachea tube should be placed.
  • Nasotracheal or cricothyrotomy may be indicated, depending on the extent of the injuries.

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ED Treatment
  • With the exception of condylar fractures, many mandibular fractures are associated with mucosal, gingival, or tooth socket disruption, and should be considered open fractures:
    • Patients should receive antibiotics such as penicillin or erythromycin to cover intra-oral anaerobic pathogens.
  • Tetanus prophylaxis if appropriate
  • Definitive care usually consists of reduction and fixation by wiring upper and lower teeth in occlusion for 4–6 wks:
    • This may not be possible initially due to patient instability or local edema.
    • Linear, nondisplaced, or greenstick fractures may be treated with soft diet without wiring.
  • If mandible dislocation is present, bilateral downward pressure while the jaw is open placed on the occlusal surface of the posterior lower teeth while grasping the mandible:
    • The goal is to free the condyle from its anterior position to the eminence.
    • The operator's thumbs are placed on the external oblique line of the mandible (lateral to the third molar area) or, after wrapping the thumbs in gauze, on the occlusal surface of the lower molars. The other fingers are curled under the mandible. The patient is asked to open wide, as if yawning, and the operator then applies downward force on the molars while applying upward force over the chin until the mandible reduces (2).
    • Once reduced, the patient should be placed in a Barton bandage for temporary immobilization until they receive definitive care.
    • Reduction is facilitated by muscle relaxants (diazepam or midazolam), or anesthetic injection of mastication muscles.
    • A bite block should be used or examiner's fingers should be wrapped in gauze to prevent injury.
Medication
  • Use of preoperative and perioperative antibiotics in mandible fractures with dentate involvement is well established to reduce the risk of infection (3).
  • Diazepam: Adult: 10 mg IV; peds: 0.1–0.2 mg/kg/dose IV
  • Midazolam: Adult: 2–5 mg IV; peds: Safety not established, but 0.02–0.05 mg/kg/dose have been used
  • Penicillin: Adult: 500 mg PO q.i.d.; peds: 25–30 mg/kg/24 hr divided q6h PO
  • Erythromycin: Adult: 500 mg PO q.i.d.; peds: 30–50 mg/kg/24 hr divided q6–8h PO
Surgery/Other Procedures
  • With the exception of condylar fractures, many mandibular fractures are associated with mucosal, gingival, or tooth socket disruption and should be treated as open fractures.
  • Patients should receive antibiotics such as penicillin or erythromycin to cover oral anaerobic microbes.
  • Patients should have their tetanus updated if needed.
  • Definitive care usually consists of reduction and fixation by wiring upper and lower teeth in occlusion for 4–6 wks.
  • Linear, nondisplaced, or greenstick fractures may be treated with a soft/liquid diet without wiring.
In-Patient Considerations
Admission Criteria
  • Those fractures in which there is significant displacement or associated dental trauma, or those fractures that are thought to be open, require urgent specialty consultation for admission.
  • The severity of associated trauma may indicate admission.
  • Any patient with the potential for airway compromise, including oropharyngeal edema or bilateral mandibular body fractures, should be admitted.
  • An unreliable patient with nondisplaced fractures should be admitted for definitive fixation.
  • In the pediatric population, if the mechanism of injury is not appropriate to the injuries seen, evaluate for child abuse.
Discharge Criteria
Relatively asymptomatic patients with nondisplaced, closed fractures may be discharged on analgesics and a soft diet. They should be referred to an otorhinolaryngologist or an oral maxillofacial surgeon within 1–2 days.
Ongoing Care
Patient Education
Alcohol abuse plays a major role in the etiology of mandibular fractures. It results in a higher rate of complications either secondary to noncompliance or as a result of metabolic dysfunction.
Prognosis
  • Patients will usually be immobilized for 4–6 wks, and can resume contact sports within 1–2 mos after treatment with appropriate protective equipment (eg, customized headgear to provide protection).
  • A better prognosis is achieved with removal of grossly diseased teeth.
  • Physical therapy is also recommended to improve jaw opening.
Complications
  • Treatment should occur as soon as possible. Prolonged delay in treatment contributes to infection.
  • Immobilization of the fracture segments is perhaps the most important aspect in avoiding delayed union, nonunion, and infection.
References
1. Alonso LL, Purcell TB. Accuracy of the tongue blade test in patients with suspected mandibular fracture. J Emerg Med. 1995;13:297–304.
2. Ellis E, Moos KF, el-Attar A. Ten years of mandibular fractures: an analysis of 2,137 cases. Oral Surg Oral Med Oral Pathol. 1985;59:120–129.
3. Busuito MJ, Smith DJ, Robson MC. Mandibular fractures in an urban trauma center. J Trauma. 1986;26:826–829.
Additional Reading
Luyk NH, Ferguson JW. The diagnosis and initial management of the fractured mandible. Am J Emerg Med. 1991;9:352–359.
Miles BA, Potter JK, Ellis E. The efficacy of postoperative antibiotic regimens in the open treatment of mandibular fractures: a prospective randomized trial. J Oral Maxillofac Surg. 2006;64:576–582.
Shepherd SM, Lippe MS. Maxillofacial trauma. Evaluation and management by the emergency physician. Emerg Med Clin North Am. 1987;5:371–392.
Shorey CW, Campbell JH. Dislocation of the temporomandibular joint. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2000;89:662–668.
Codes
ICD9
  • 802.20 Closed fracture of unspecified site of mandible
  • 802.21 Closed fracture of condylar process of mandible
  • 802.22 Closed fracture of subcondylar process of mandible
Clinical Pearls
  • Consider a mandibular fracture for any athlete that has facial deformity, dysphagia, and mandibular pain after direct trauma to the face.
  • The first priority is to maintain the airway and the C-spine.
  • This fracture must be treated as an open fracture with antibiotics.


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