Exodontia.Info
Dislocation of the Mandible /
Jaw Dislocation / TMJ Subluxation
Predisposing Factors for Jaw Dislocation:

  • Most dislocations occur spontaneously on opening
    the mouth widely for yawn, dental work, during an
    epileptic seizure
  • Trauma may also produce dislocation
  • Trauma involving a downward force on partially
    opened jaw
  • Those with previous dislocations are at much greater
    risk for repeat dislocation
  • Shallow mandibular fossa may predispose to
    dislocation
  • Connective tissue diseases like Marfan’s or Ehlers-
    Danlos may have increased risk
  • May eventually result in osteoarthritis in TM joint
Clinical Findings:

  • Dislocations of the lower jaw (mandible) tend to be uncomfortable but not
    severely painful for the patient
  • The presence of a jaw fracture increases the pain
  • Patients are unable to close mouth completely
  • Difficulty speaking and, possibly, swallowing
  • Dislocations may be one-sided or both (unilateral or bilateral)
  • The lower jaw comes forward (pro-gnathic) appearance to jaw when both are
    dislocated
Useful Websites:

Canadian Dental Association

Drugs.com

Emedicine.com

Medscape

Merck Manual


Useful Articles:

Ind J Anaesth 2004.  Temporomandibular Joint (TMJ) Dislocation During LMA
Insertion

J Craniofacial Surg 2008.  A Clinical Study on Treatment of Temporomandibular
Joint Chronic Recurrent Dislocations by a Modified Eminoplasty Technique

Pakistan Oral & Dent J 2008.  Treatment of TMJ Recurrent Dislocation through
Eminectomy - A Study

Anesth Prog 2009.  Use of Masseteric & Deep Temporal Nerve Blocks for
Reduction of Mandibular Dislocation

Annals Plastic Surgery 2009.  Temporomandibular Joint Dislocation Reduction
Technique.  A New External Method vs. the Traditional

BJOMS 2009.  Long-Term Efficacy of Botulinum Toxin Type A for the Treatment of
Habitual Dislocation of the TMJ

JOMS 2009.  Autologous Blood Injection for the Treatment of Chronic Recurrent
TMJ Dislocation

Head & Face Medicine 2011.  Evaluation of the Mechanism & Principles of
Management of TMJ Dislocation.  Systematic Review of Literature & a Proposed
New Classification of TMJ

BJOMS 2012.  Technical Note.  Intra-Oral High Condylotomy for a Case of Chronic
Mandibular Dislocation

Ann Dent Specialty 2014.  Case Report.  Autologous Blood Injection for Treatment
of Recurrent TMJ Dislocation

Patient.co.uk 2014.  Mandibular Dislocation
Last Updated 2nd May 2016
Treatment:

Reduction:

Once radiographs have been obtained that confirm a
dislocation and exclude a
mandibular fracture, reduction attempts may proceed. Patients with mandibular
fractures
should be referred to the OMFS Department.  Uncomplicated
dislocations can be managed in the A&E ± LA ± conscious sedation.

If the
dislocation has just happened, no sedation or LA is needed.  The longer the
patient has been
dislocated, the more likely either LA ± sedation or in more severe
cases, GA.

Relocation: An initial attempt can be made for the patient to self-relocate by
eliciting the
gag-reflex.  Stimulation of the soft palate can induce the patient to
gag.  This can spontaneously re-locate the
subluxed mandible.

Gauze pads should be wrapped around both thumbs to prevent human bite injuries
as the
mandible is reduced. The thumbs are placed on the lower molars (or over
the
retro-molar pads) and the inferior surface of the mandible is grasped with the
fingers on each side. Downward pressure is exerted on the lower molars to free
the
condyle from its entrapped position in front of the articular eminence.

Following this, the
mandible is eased backwards to return it to its anatomic
position. Successful reduction is usually evident as the teeth will close rapidly due
to
masseter spasm and a palpable (and sometimes audible) clunk occurs on
reduction. The clinician must beware of having their thumbs being trapped in an
inadvertent human bite as the
mandible relocates.
Dislocation of the mandible / jaw dislocation / TMJ
subluxation
is an infrequent A&E presentation.

The condition is discomforting to the patient, although
most are not in severe pain.  In the majority of cases, the
mandible (lower jaw) can be reduced by the A&E staff
using simple techniques.  Rarely, a
mandibular dislocation
may require open reduction under general anæsthesia.

Once the
condyle (see below diagram) comes out of its
fossa, it comes to lie in front of the articular eminence
and is mechanically blocked from spontaneously moving
back into its correct position (in the
fossa).

Spasm of the
masseter and pterygoid muscles (chewing
muscles) results in
trismus (limited mouth opening) and
further traps the
condyle in its dislocated position.  The
resulting
dislocation may be one sided or both. In either
case, the patient will be unable to completely close the
mouth and will often have difficulty speaking.

The
dislocation is surprisingly not very painful unless an
associated
mandibular fracture is present.
Imaging Findings:

  • Conventional X-ray is usually diagnostic
  • Mandibular condyle lies forward (anterior) to the articulate eminence on one
    or both sides
Barton Bandage to reduce
the chance of further
TMJ
Subluxation
Follow-Up

Further Inpatient Care:

In the rare cases of mandible dislocation that cannot be reduced by the method
described above, attempted closed reduction under GA or open reduction may be
required. Similarly, chronic
dislocations or fractures / dislocations of the mandible
are best reduced by
OMFS or ENT specialists.

Further Outpatient Care:

Successfully relocated
mandibular dislocations do not require any specific
ongoing treatment, although the patient should be cautioned against wide opening
of the mouth, which could easily cause a recurrence.

All patients with reduced
mandibular dislocations should be followed-up by an
appropriate specialist because of the possibility of jaw instability,
ligamentous
damage
and chronic TMJ pain.


Complications:

Serious complications from
mandibular dislocation are rare.  There are several
complications that are associated with the
dislocation and reduction.

Dislocation complications:

Fracture of the
mandibular condyle can occur during dislocation. Open fractures
are at risk for infection and
osteomyelitis. Interposition of soft tissues may make
the
dislocation irreducible.

Injury to the
external carotid artery and facial nerve have been reported.

Complications of Reduction:

The clinician accomplishing 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.

Prognosis:

Because the
dislocation occurs in anatomically predisposed individuals and
disrupts the
joint capsule and ligaments that stabilise the TMJ, recurrent
dislocation is very common.

Recurrent
dislocation often results in osteo-arthritis of the TMJ with chronic pain
and inflammation.

There are many surgical interventions to correct chronic
dislocation and painful
TMJ syndrome
that are described in the ENT literature. Because so many of the
patients with
mandible dislocation experience recurrent dislocation, it is advisable
to 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.
Confirmation of relocation: Repeat radiographs are indicated to confirm reduction
and exclude the possibility of fracture during reduction.

The patient should be observed for
airway patency and if sedation has been used,
vital signs monitored until the effects of the sedatives have worn off.

The patient should be cautioned to avoid wide opening of the mouth to prevent
recurrent
dislocation. A Barton's bandage is applied to prevent wide mouth opening
and recurrent
dislocation.
Relocation of the subluxed TMJ - note,  
gauze wrapped around the thumbs