Temporomandibular (TMJ) Dislocation and Reduction Techniques

Mechanism or Injury — Anterior TMJ dislocation are the most common type of jaw dislocation. They typically occur due to opening the mouth in an extreme manner such as yawning. Others causes include trauma, dystonic reactions, seizures, or tetanus infection. Iatrogenic dislocations may occur during anesthesia induction and upper endoscopy. Symmetric mandibular dislocation is most common, but unilateral dislocations can also occur. Superior and posterior dislocations of the TMJ are rare and usually associated with trauma.

Risk Factors – Patients who are prone to mandibular dislocations include those with an anatomic mismatch between the temporal bone and the mandible as well as those patients who have either laxity or torn temporomandibular ligaments.

Anatomy — The TMJ consists of the articulation of the temporal and mandibular bones. TMJ dislocation occurs when the condyle travels anteriorly along the articular eminence and becomes locked in the anterior superior aspect of the eminence, preventing closure of the mouth. Dislocation causes stretching of ligaments and then severe spasm of the muscles that open and close the mouth. The resultant trismus prevents spontaneous reduction.

Presentation — Diagnosis of TMJ dislocation is made based upon clinical findings. The patient is unable to close the mouth and may have garbled speech and drooling.

It is recommended that children and most adult patients with non-traumatic TMJ dislocation should undergo panoramic jaw radiographs to exclude a mandibular fracture. Skeletally mature patients + no trauma mechanism + typical clinical findings of TMJ dislocation + no other clinical findings suggestive of fracture may undergo reduction without imaging.

Indication for Consultation — The following patients should undergo prompt referral to an oral and maxillofacial surgeon:

●Patients with an anterior TMJ dislocation + fracture
●Patients who fail reduction of an anterior TMJ dislocation despite multiple attempts.

●Patients who have had more than two prior TMJ dislocations.
●Patients with superior or posterior dislocations.

How to reduce a TMJ dislocation:

Preparation — Sedation and muscle relaxation with a benzodiazepine and pain medication is advised. Massaging the masseter muscles in order to relax and fatigue may facilitate manual reduction.

Supplies:
The following equipment should be assembled: Gloves, Gauze, Tongue blades, Bite block, Yankauer suction, and McGill forceps

Techniques:

Gag the patient — During the reflex, inhibition of the muscles of mouth closure permits the mandible to descend, thereby freeing the condyle in some patients.

Intra-oral reduction — These maneuvers require clinicians to place their thumbs or fingers within the mouth. Padding of the examiner’s hands and a bite block is suggested to prevent injury to the examiner.

Grasp the mandible with both hands; the thumbs rest inside the mouth on the ridge of the mandible adjacent to the molars, and the fingers wrap around the outside of the jaw.
Apply downward pressure to the mandible to free the condyles from the anterior aspect of the eminence; the mandible is then guided posteriorly and superiorly back into the temporal fossae.
Alternatively, the clinician may stand behind the patient who is seated in a chair and then proceeds as follows:
- Grasp the mandible and place the thumbs on the ridge of the mandible adjacent to the molars or on the occlusal surfaces with gauze protection and precautions to prevent aspiration as described above. The fingers are wrapped around the chin.
- Apply downward force with the thumbs and then apply upward pressure with the fingers on the chin.

Extra-oral reduction — This technique has the advantage of not requiring the clinician to place fingers or thumbs in the mouth.

On one side, the clinician grasps the mandibular angle with the fingers of the hand and places the thumb over the malar eminence of the maxilla.
On the other side, the clinician places the thumb just above the palpated, displaced coronoid process and fingers behind the mastoid process.
At the same time, the clinician pulls the mandibular angle forward on one side while pushing back on the coronoid process on the other side, causing one side of the mandible to reduce.

Syringe — A 5- or 10-mL syringe is placed between the posterior upper and lower molars or gums on one of the affected sides. The size of the syringe depends on which can fit most easily and still engage both upper and lower teeth.

The patient is then instructed to gently bite down on the syringe while rolling it back and forth between the teeth until the dislocation on that side is reduced.
Typically the opposite side reduces spontaneously. If this does not occur, then the syringe can be placed on the opposite side and reduction performed in the same manner.

Tongue Depressor Technique – The goal is to fatigue the masseter muscles to make the reduction easier. (See link below for video on this technique.)

https://www.youtube.com/watch?v=Kp8AzHIC0hM#action=share

Aftercare and Follow-Up — Apply a bandage around the mandible and head of the patients. Post reduction imaging is recommended to ensure adequate reduction and to exclude the presence of an avulsion fracture. (A panoramic radiograph of the jaw is preferred to plain films of the jaw.)

Sample Discharge Instructions:

Avoid extreme opening of the jaw for three weeks.
Support the lower jaw when yawning.
Apply warm compresses to the TMJ area for 24 hours.
Maintain a soft diet for one week.
Ibuprofen for pain and swelling as needed.
Follow-up with and Ear, Nose, and Throat Physician or an Oral Maxillofacial Surgeon in two to three days for further evaluation.

There are no studies that compare any of the above mentioned methods with regards to patient-oriented outcomes or clinical feasibility.

Presented By: Dr. Brenda Oiyemhonlan, MD (PGY IV – Chief Resident)

References:
Marx, J, Wall, R, and Hockberger. “Temopormandibular Dislocations.” Head and Neck Disorders in Rosen’s Emergency Medicine – Concepts and Clinical Practice. 906-907

Reduction of Temporomandibular Joint Dislocation. Uptodate. Accessed on 1/18/2016 via http://www.uptodate.com.newproxy.downstate.edu/contents/reduction-of-temporomandibular-joint-tmj dislocation?source=machineLearning&search=tmj+reduction&selectedTitle=1~150&sectionRank=1&anchor=H8320372#H8320372