AUTHOR AND EDITOR INFORMATION

Section 1 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

INTRODUCTION

Section 2 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

Background

Dislocation of the mandible is an infrequent presentation in the ED. The condition causes the patient discomfort, although most are not in severe pain. In a majority of cases, the mandible can be reduced by using simple techniques. Rarely, a mandibular dislocation may require open reduction under general anesthesia.

Pathophysiology

Certain patients are predisposed to mandibular dislocation at the temporomandibular (TMJ) joint by virtue of a shallow mandibular fossa in the temporal bone or an underdeveloped condyle of the mandible. In addition, patients with connective tissue diseases, such as Marfan syndrome or Ehlers-Danlos syndrome, can also have a reported increased incidence of mandibular dislocation and subluxation. Most cases of dislocation occur spontaneously when the jaw is opened wide (eg, while yawning, yelling, eating, singing, during prolonged dental work, endoscopy) or during a seizure. Traumatic dislocations also occur when downward force is applied to a partially opened mandible.

Once the condyle is pried out of its fossa, it lies anterior to the articular eminence and is blocked mechanically from spontaneously reducing. Spasm of the masseter and pterygoid muscles results in trismus and further traps the condyle in its dislocated position. The resulting dislocation may be unilateral or bilateral. In either case, patients are unable to close their mouths completely and often have difficulty speaking. The dislocation is surprisingly not very painful unless an associated mandibular fracture is present. In rare instances, severe trauma may result in displacement of the condyle medially into the cranial fossa.

Mortality/Morbidity

Mortality is not associated with mandibular dislocation. Morbidity is due to an increased tendency for recurrent dislocation and for eventual development of painful osteoarthritis of the traumatized joint or TMJ syndrome. Delayed reductions in fracture/dislocations may result in limited mobility secondary to fibro-osseous ankylosis.

CLINICAL

Section 3 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

History

• The patient often is unable to enunciate clearly; this may make the history difficult to ascertain. Most patients relate an uncomfortable sensation of jaw movement following maximal mouth opening, such as that associated with yawning. This is followed by an inability to close the mouth and variable amounts of pain and discomfort in the area of the mandibular fossa.
• Most patients with traumatic dislocations relate a history of being struck on a partially opened jaw with similar resulting symptoms. Rarely, a patient presents with mandible dislocation as part of a multiple trauma scenario, in which case head injuries, intoxication, or other causes of altered mental status may interfere with the patient's complaint of the mandible dislocation. In these rare cases, the dislocation may be discovered on physical examination.
• Patients may have experienced previous dislocations and complain of a recurrent dislocation.

Physical

• The physical findings depend on the duration of dislocation, presence of associated fracture, and whether the dislocation is bilateral or unilateral.
• Unilateral dislocation: The mandible is tilted and lies lower on the affected side. Associated edema, tenderness, and palpable deformity may be present in the TMJ area. The teeth cannot be closed actively or passively.
• Bilateral dislocation: When both mandibular condyles are dislocated, the patient appears to have prognathia (underbite) and has bilateral edema and tenderness in the TMJ areas. The teeth do not close actively or passively as a result of mechanical obstruction. Bilateral masseter spasm often is palpable.
• Associated fractures
• • A fracture at the base of the condyle or in the subcondylar region of the mandible allows the mandible to slide forward and mimics a dislocation. The pain associated with a fracture is greater than that with a simple dislocation.
  • Since reduction of a dislocation may result in an iatrogenic fracture of the condyle, perform this reduction gradually and gently.

Causes

• Patients with a congenitally shallow mandibular fossa or underdeveloped condyle are at risk for dislocation.
• Previous dislocations, whether from preexisting anatomic abnormalities or destruction of stabilizing ligaments, predispose patients to repeated dislocations.
• Rare causes of dislocation include Marfan syndrome, Ehlers-Danlos syndrome, malignancy, osteomyelitis, and rheumatoid arthritis, although the latter condition usually results in ankylosis of the TMJ.
• The immediate cause of dislocation is usually an exaggerated opening of the mouth that pries the condyle out of the fossa.

DIFFERENTIALS

Section 4 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

WORKUP

Section 5 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

Imaging Studies

• Plain radiography
• • Plain radiographs of the mandible, including bilateral oblique views, virtually always show the affected condyle lying anterior to the articular eminence.
  • Obtain radiographs prior to attempts at reduction because of the risk of associated fracture of the mandible. Direct attempts at reduction without imaging may be considered in patients who are chronic dislocators.
  • A Panorex view of the mandible is most accurate in detecting and characterizing mandibular fractures and reliably detects dislocations; however, the availability of Panorex is variable.
• CT scan and MRI
• • CT scan and MRI may demonstrate a dislocation, although neither is indicated in uncomplicated cases. However, in children, CT has demonstrated to be more sensitive than Panorex in detecting fractures of the condyle.
  • MRI especially is useful in visualizing structural abnormalities of the TMJ in cases of chronic jaw pain associated with TMJ syndrome.

TREATMENT

Section 6 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

Prehospital Care

No specific treatment is indicated in the field. The decision regarding self-transport versus paramedic transport is based upon factors other than the mandibular dislocation (eg, presence of multiple trauma, patient's level of pain and distress).

Emergency Department Care

• ED treatment is initiated by establishing airway patency and adequate ventilation when indicated.
• In a majority of cases, definitive diagnosis and treatment can be accomplished in the ED.
• Associated injuries in cases involving trauma (eg, cervical spine injury) take precedence over treatment of the mandible dislocation.
• The diagnosis and reduction of the mandibular dislocation should take place after more life-threatening injuries have been addressed.
• More complex cases, such as irreducible dislocations, chronic dislocations, or those with associated fractures should be treated with analgesics and referred urgently to appropriate specialists.
• Reduction
• • Once adequate radiographs, when indicated, have been obtained that confirm a dislocation and exclude a mandibular fracture, proceed with reduction attempts. Refer patients with mandibular fractures to appropriate specialists.
  • Uncomplicated dislocations can be managed in the ED. With dislocations that have occurred recently, one attempt at reduction can be made without administration of sedation (eg, conscious sedation).
  • Conscious sedation is appropriate provided that adequate monitoring can be arranged and the physician is experienced in the technique. Combining single doses of a benzodiazepine and opiate usually sedates the patient and relaxes masseter spasm sufficiently to allow manipulation of the mandible, but other medications such as ketamine or etomidate may also be considered. Local anesthesia into the TMJ also may facilitate reduction.
  • Reduction technique 1: Clinician faces the patient.
    • Seat the patient on a chair against a wall and have him or her rest his or her head against the wall for support.
    • Place gloved thumbs on the retromolar pad (ie, behind the last molar) on either side of the mandible and grasp the inferior surface of the mandible with the fingers on each side.
      
    • With elbows locked, exert downward pressure on the lower molars by bending your knees to free the condyle from its entrapped position anterior to the articular eminence.
    • Ease the mandible posteriorly to return it to its anatomic position.
    • Successful reduction is usually evident, as the teeth close rapidly due to masseter spasm, and a palpable (and sometimes audible) clunk occurs on reduction.
    • The physician must beware of having her or his thumbs trapped in an inadvertent human bite as the mandible relocates. Because of this risk, the common practice of wrapping both thumbs with gauze and pressing down on both molars is discouraged.
  • Reduction technique 2: Clinician stands behind the patient.
    • This technique is preferable when deep conscious sedation precludes having the patient sit up.
    • Place the thumbs on the retromolar pads and grasp the mandible anteriorly with the fingers.
    • Exert caudal pressure and the mandible usually reduces once sufficient distraction has occurred. If not, slight posterior pressure may be required to complete the reduction.
  • Confirmation of relocation: Repeat radiographs to confirm reduction and exclude the possibility of fracture during reduction. Observe the patient for airway patency and monitor vital signs until the effects of the sedatives have worn off. Caution the patient to avoid opening the mouth widely to prevent recurrent dislocation. Barton bandages rarely are used and are indicated primarily in patients who are unable to understand or follow discharge instructions (eg, developmentally delayed). For most patients, the Barton bandage is unnecessary, and instructions to avoid wide mouth opening for several days and to begin range of motion exercises are sufficient.

Consultations

All patients should be referred for follow-up by an otolaryngologist or oral-maxillofacial surgeon. More urgent consultation is indicated for irreducible dislocations or fracture/dislocations of the mandible that may require operative intervention.

MEDICATION

Section 7 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

Sedation and analgesia are indicated if reduction is attempted. The medications traditionally employed for this purpose are diazepam and meperidine. Other conscious sedation protocols can be employed providing the patient maintains an adequate gag reflex. Deep conscious sedation is not desirable, as the patient should remain seated during relocation. Certain medications that can cause masseter spasm (eg, methohexital, chlordiazepoxide, phenothiazines) should be avoided, as this complication would prevent relocation of the mandible.

Drug Category: Analgesics

Pain control is essential to quality patient care. It ensures patient comfort, promotes pulmonary toilet, and aids physical therapy regimens. Many analgesics have sedating properties that benefit patients with injuries.

Drug Category: Anxiolytics

Patients with painful injuries usually experience significant anxiety. Anxiolytics allow the clinician to administer a smaller analgesic dose to achieve the same effect.

FOLLOW-UP

Section 8 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

Further Inpatient Care

• In the rare cases of mandible dislocation that cannot be reduced by the methods described above, closed reduction under general anesthesia or open reduction may be required. Dislocations associated with fractures of the mandible are best reduced by oral-maxillofacial surgeons or otolaryngologists.

Further Outpatient Care

• Successfully relocated mandible dislocations do not require any specific ongoing treatment, although the patient should be cautioned against opening the mouth wide, which could easily cause a recurrence.
• A soft collar may be considered for support of the TMJ after reduction.
• All patients with reduced mandible dislocations should be followed up by an appropriate specialist because of the possibility of jaw instability, ligamentous damage, and chronic TMJ pain.

Transfer

• Patients with dislocation of the mandible can be transferred providing no severe associated injuries are present, vital signs are stable, and the airway is patent.
• In many cases, relocation is simple to perform at the initial ED, and the patient can be referred for ongoing care at another facility, precluding the need for transfer.

Complications

• Serious complications from mandibular dislocation are rare. Several complications are associated with the dislocation and reduction, however.
• Dislocation complications
• • Fracture of the mandibular condyle can occur during dislocation.
  • Open fractures are at risk of infection and osteomyelitis.
  • Interposition of soft tissues may make the dislocation irreducible.
  • Theoretically, massive edema or bleeding into the pharynx may compromise the airway, although this complication has not been reported.
  • Injury to the external carotid artery and facial nerve has been reported.
• Complications of reduction
• • The practitioner performing the reduction may sustain a human bite as the jaw closes rapidly on reduction.
  • The mandibular condyle may fracture as it passes under the articular eminence.
  • Depending on the medications used for sedation/analgesia or conscious sedation, the patient may experience hypotension, apnea, dysrhythmias, allergic reaction, or a host of other less common complications particular to the medications used.

Prognosis

• As the dislocation occurs in anatomically predisposed individuals and disrupts the joint capsule and ligaments that stabilize the TMJ, recurrent dislocation is very common. Recurrent dislocation often results in osteoarthritis of the TMJ with chronic pain and inflammation.
• Many surgical interventions are available to correct chronic dislocation and painful TMJ syndrome described in the OMF and ENT literature. As many patients with mandible dislocation experience recurrent dislocation, refer all of these patients to an appropriate specialist for follow-up.

Patient Education

• Patients should be instructed to avoid opening their mouths widely to prevent recurrent dislocation.
• For excellent patient education resources, visit eMedicine's Back, Ribs, Neck, and Head Center, Breaks, Fractures, and Dislocations Center, and Teeth and Mouth Center. Also, see eMedicine's patient education articles Temporomandibular Joint (TMJ) Syndrome, Broken Jaw, and Broken or Knocked-out Teeth.

REFERENCES

Section 9 of 9

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

• Bauss O, Sadat-Khonsari R, Fenske C, et al. Temporomandibular joint dysfunction in Marfan syndrome. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. May 2004;97(5):592-8. [Medline].
• Chacon GE, Dawson KH, Myall RW, Beirne OR. A comparative study of 2 imaging techniques for the diagnosis of condylar fractures in children. J Oral Maxillofac Surg. Jun 2003;61(6):668-72; discussion 673. [Medline].
• Fonseca RJ, Walker RV, eds. Management of injuries to the temporomandibular joint region. In: Oral and Maxillofacial Trauma. Philadelphia: WB Saunders Co;1991:430-1. [Medline].
• Laskin DM. Temporomandibular joint disorders. In: Frederickson JM, Krause CJ, eds. Otolaryngology: Head and Neck Surgery. 2nd ed. St. Louis: Mosby-Yearbook;1993:1443-50. [Medline].
• Mangi Q, Ridgway PF, Ibrahim Z, Evoy D. Dislocation of the mandible. Surg Endosc. Mar 2004;18(3):554-6. [Medline].
• Thexton A. A case of Ehlers-Danlos syndrome presenting with recurrent dislocation of the temporomandibular joint. Br J Oral Surg. Mar 1965;27:190-3. [Medline].
• van der Linden WJ. Dislocation of the mandibular condyle into the middle cranial fossa: report of a case with 5 year CT follow-up. Int J Oral Maxillofac Surg. Apr 2003;32(2):215-8. [Medline].

Article Last Updated: Dec 13, 2005