Mandibular dislocation

Background

• Anterior Dislocation
  • Most common
  • Mandibular condyle is forced in front of the articular eminence
  • Risk factors: Prior dislocation, weak capsule, torn ligaments
  • Often occurs spontaneously while patient is yawning, "popping" ears, or laughing
• Posterior Dislocation
  • Follows a blow to the mandible that may or may not break the condylar neck
  • Condylar head may prolapse into the external auditory canal
• Lateral Dislocation
  • Often associated with mandibular fracture
• Superior Dislocation
  • Occur from blow to the partially opened mouth
  • Associated with cerebral contusions, facial nerve palsy, deafness

Clinical Features

• Anterior Dislocation
  • Difficulty speaking or swallowing
  • Malocclusion
  • Pain localized anterior to the tragus
  • Prominent-appearing lower jaw
  • Preauricular depression
• Posterior Dislocation
  • Must examine the external auditory canal
• Lateral Dislocation
  • Condylar head is palpable in the temporal space

Differential Diagnosis

Jaw Spasms

• Dystonic reaction
• Acute tetanus
• Conversion disorder
• Mandibular dislocation
• Electrolyte abnormality
  • Hypocalcemic tetany
  • Magnesium
• Meningitis
• Seizure disorder
• Strychnine poisoning
• Akathisia
• Stroke
• Drug toxicity (anticholinergic, phenytoin, valproate, carbamazepine)
• Torticollis
• PTA
• Rabies
• TMJ

Evaluation

• Spontaneous, Atraumatic Anterior Dislocation: Clinical Diagnosis.
• Traumatic Dislocation: Obtain a CT scan.
• Always examine the cranial nerves to rule out concomitant injury.

Management

Standard Technique

1. Place patient in seated position (anterior approach) or supine (posterior approach)
   1. Advisable to wrap thumbs in gauze to guard against accidental bite
2. Placed gloved thumbs in patient's mouth over the occlusal surfaces of the molars, or lateral to patient's molars in buccal fold (to avoid being bitten)
3. Apply pressure downward (toward the feet) and then backward (posteriorly)

Posterior position

Wrist Pivot Method

1. Place patient in seated position
2. While facing the patient, grasp the mandible with your thumbs at the apex of the mentum and fingers on the occlusal surface of the inferior molars.
3. Apply cephalad force with the thumbs and caudad pressure with the fingers
4. Then pivot your wrists.

• Note: This is a more physiologic reduction technique for the provider, allowing greater and more sustained force to be exerted.

Tips

1. Massage the TMJ externally prior to beginning the reduction attempt.
2. Don't Forget the Analgesia!
   1. Consider IV benzodiazepines, opioids, or procedural sedation.
   2. Inject local anesthetic into the preauricular depression just anterior to the tragus.
3. If dislocation is bilateral it may be easier to relocate one side at a time.

Disposition

Admit

• Open dislocation
• Superior dislocation
• Associated with fracture
• Nerve injury
• Inability to reduce

Discharge

Spontaneous, successfully reduced anterior dislocation with:

• Soft diet
• Tell patient not to open mouth wider than 2cm x 2wks
• Tell patient to support the mandible with a hand when they yawn

References

Authors

Mark Russell, Michael Gottlieb, Jordan Swartz, Christopher Kim, Matthew, Neil Young, Ross Donaldson, Kevin Lu