Mandible 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

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

Evaluation

Always examine the cranial nerves to rule out concomitant injury.

Spontaneous

• Likely an atraumatic anterior dislocation
  • Clinical diagnosis (no imaging required)

Traumatic Dislocation

• Obtain a CT scan to evaluate

Management

Wrist Pivot Method

• Place patient in seated position
• 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.
• Apply cephalad force with the thumbs and caudad pressure with the fingers
• Then pivot your wrists.

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

Older "Traditional" Technique

Posterior position

• Place patient in seated position (anterior approach) or supine (posterior approach)
  • Advisable to wrap thumbs in gauze to guard against accidental bite
• 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)
• Apply pressure downward (toward the feet) and then backward (posteriorly)

Tips

• Massage the TMJ externally prior to beginning the reduction attempt.
• Don't Forget the Analgesia!
  • Consider IV benzodiazepines, opioids, or procedural sedation.
  • Inject local anesthetic into the preauricular depression just anterior to the tragus.
• 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