Temporomandibular joint (TMJ) dislocation

INTRODUCTION — This topic will review the evaluation and reduction of temporomandibular joint (TMJ) dislocations. The evaluation and management of pediatric dental injuries and jaw fractures are discussed separately. (See "Evaluation and management of dental injuries in children" and "Mandibular (jaw) fractures in children" and "Initial evaluation and management of facial trauma in adults".)

EPIDEMIOLOGY AND RISK FACTORS — Anterior TMJ dislocation commonly follows extreme opening of the mouth (eg, during eating, yawning, laughing, singing, kissing, vomiting, or dental treatment) and less often occurs after trauma [1-3]. Dislocation also can result from dystonic reactions to drugs, seizures, or tetanus infection [4,5]. In addition, iatrogenic dislocation during anesthesia induction and upper endoscopy have been described [6,7]. Symmetric mandibular dislocation is most common, but unilateral dislocation with the jaw deviating to the opposite side can also occur.

Superior and posterior dislocations of the TMJ are very rare and usually associated with high-energy trauma [8]. Superior dislocations occur in association with mandibular fossa fractures. Posterior dislocations may be associated with disruption of the external auditory canal or fracture of the temporal plate.

Patients prone to mandibular dislocation include those with an anatomic mismatch between the fossa and articular eminence, weakness of the capsule and the temporomandibular ligaments (eg, patients with Ehlers-Danlos or Marfan syndrome), and torn ligaments. Patients who have had one episode of dislocation are predisposed to recurrence [9].

ANATOMY — The TMJ consists of the articulation of the temporal and mandibular bones (figure 1). 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 (figure 2) [3]. Dislocation results in stretching of the ligaments and is associated with severe spasm of the muscles that open and close the mouth (ie, the masseter, medial and lateral pterygoid, and temporalis) (figure 3) [10,11]. The resultant trismus prevents the condyle from returning to the mandibular fossa.

CLINICAL FEATURES — TMJ dislocation presents with mandibular pain and inability to close the mouth after extreme opening (eg, yawning, eating, singing, or laughing), excessive muscle contraction of the muscles of mastication (eg, due to dystonic reaction, seizures, or tetanus), or after facial trauma.

On physical examination, the patient is unable to close the mouth and may have garbled speech and drooling [1,12]. A depression may be noted in the preauricular area. Palpation of the TMJ reveals one or both of the condyles trapped in front of the articular eminence and spasm of the muscles of mastication. In addition, the coronoid process of the mandible becomes prominent and palpable just below the maxilla (image 1). With bilateral TMJ dislocation the jaw is open and fixed in the midline. With unilateral jaw dislocation, the jaw is open and deviated to the unaffected side.

DIAGNOSIS — The diagnosis of TMJ dislocation is made clinically. All children and most adult patients with nontraumatic TMJ dislocation should also undergo panoramic jaw radiographs or mandibular computed tomography (CT) to exclude a mandibular fracture. Whenever possible, panoramic jaw radiographs are preferred in children because of lower radiation exposure. Skeletally mature patients with no trauma mechanism, typical clinical findings of TMJ dislocation, and no other clinical findings suggestive of fracture may undergo reduction without radiographs if obtaining radiographs poses an undue delay in reduction.

Patients with a possible jaw dislocation in the setting of facial trauma warrant CT of the face to fully assess for associated fractures and other injuries. (See "Initial evaluation and management of facial trauma in adults", section on 'Facial injury'.)

DIFFERENTIAL DIAGNOSIS — Nontraumatic TMJ dislocation may occasionally be confused with infectious processes that cause trismus and/or drooling such as peritonsillar abscess, retropharyngeal abscess, or epiglottitis.

The key differentiating findings are as follows:

●Patients with peritonsillar abscess, retropharyngeal abscess, or epiglottitis typically complain of throat or neck pain, are febrile, may have characteristic findings on physical examination, and, if trismus is present, cannot open their mouth widely. (See "Peritonsillar cellulitis and abscess", section on 'Typical presentation' and "Epiglottitis (supraglottitis): Clinical features and diagnosis", section on 'Clinical presentation'.)

●By contrast, patients with nontraumatic TMJ dislocation report jaw pain, have a widely opened mouth that they cannot close, a normal appearing oropharynx, and are usually afebrile.

Traumatic TMJ dislocations may also appear similar to bilateral fractures of the mandibular condyles on physical examination. CT of the face differentiates these injuries from each other and also identifies when they coexist.

INDICATIONS FOR SUBSPECIALTY CONSULTATION OR REFERRAL — The following patients should undergo prompt referral to an oral and maxillofacial surgeon:

●Patients with an anterior TMJ dislocation in association with a fracture.

●Patients who fail reduction of an anterior TMJ dislocation despite multiple attempts. Of note, clinicians who use the traditional intraoral method may be able to reduce the dislocation with an alternative technique such as the syringe or extraoral technique [13-16]. (See 'Reduction' below.)

●Patients who have had more than two prior TMJ dislocations.

●Patients with superior or posterior dislocations.

In some instances, peripheral nerve blocks of the masseteric and deep temporal nerves in conjunction with local infiltration of the TMJ capsule may permit reduction of TMJ dislocations that are otherwise difficult to reduce, avoiding the need for procedural sedation or general anesthesia [17].

Patients in whom reduction is difficult or who have more than one recurrence may require additional intervention.

REDUCTION

Preparation — Patients with TMJ dislocation are usually anxious and in pain. The patient and, for children, the caregiver should receive an explanation concerning the injury and the procedural approach. Case reports indicate that successful reduction without sedation may be accomplished using techniques such as the syringe, intraoral/wrist pivot, or extraoral technique [13-15].

If manual reduction by the traditional method is planned, sedation and muscle relaxation with a benzodiazepine (eg, intravenous [IV] midazolam) and pain medication (eg, IV fentanyl) is advised. (See "Procedural sedation in children: Approach" and "Procedural sedation in adults in the emergency department: General considerations, preparation, monitoring, and mitigating complications".)

Approach — Several different techniques have been described for reduction of TMJ dislocation [8,13-16,18]. We suggest that the clinician attempt reduction using the syringe technique first because it does not require placement of the finger or thumbs on the occlusal surfaces of the molars and may be accomplished quickly without sedation [19]. However, evidence is lacking regarding which technique is most effective. Thus, while clinicians should use the technique with which they are most comfortable, the following approach is suggested:

●The syringe method is attempted for one to two minutes, if necessary. Some patients may succeed with variation in the suggested motion (eg, "roll the syringe," "try to push your chin forward," "try to bite your front teeth together," or "move your jaw from side to side"). Even several attempts add very little time, risk, or discomfort and, when successful, avoid more invasive alternatives.

●Manual reduction using any of the intra-oral approaches described below, making no more than two attempts without procedural sedation.

●Manual reduction with procedural sedation.

●Consultation or referral to an oral and maxillofacial surgeon.

Although gagging the patient can also reduce nontraumatic TMJ dislocation [13], we do not advocate this method because of the risk of vomiting and aspiration.

Syringe method — With this technique, a 5- or 10-mL syringe is placed between the posterior upper and lower molars or gums on one of the affected sides (picture 1). The size of the syringe is chosen by which syringe can fit most easily but still engage both upper and lower teeth [16]. The patient is then instructed to gently bite down on the syringe while rolling it forward and backward between the teeth until the dislocation on that side is reduced. Typically, the opposite side reduces spontaneously. If this does not occur, the syringe can be placed on the opposite side and reduction performed in the same manner.

In a case series of 31 patients with acute nontraumatic TMJ dislocations, the syringe technique was successful in 30 individuals. Furthermore, successful reduction occurred in less than one minute in 77 percent of patients [16].

Intraoral technique — Manual reduction may be accomplished by one of several intraoral maneuvers [3,8,18]. These maneuvers require clinicians to place their thumbs or fingers within the mouth. In addition to padding on the examiner's hands, a bite block is suggested to prevent injury.

The following equipment should be assembled:

●Gloves

●Gauze (if thumbs require wrapping, trailing appendage or gauze with strings are preferred to avoid aspiration)

●Tongue blades (shortened to be secured to the upper and lower surfaces of the thumbs of the clinician using gauze) or aluminum finger splints that can be bent around the thumbs and taped in place

●Bite block

●Yankauer suction

●Magill forceps (to retrieve gauze from the mouth should it become dislodged)

The clinician may also choose to massage the masseter muscles in order to relax and fatigue them, which may facilitate manual reduction.

Manual reduction methods include:

●Traditional – For the traditional technique the clinician faces the patient and then proceeds as follows [3,8,18]:

•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. Some clinicians prefer to place the thumbs on the occlusal surfaces of the teeth. In this case, the thumbs must be wrapped with gauze to protect them when reduction is accomplished because the masseters can contract with tremendous force. Some clinicians also use shortened tongue blades on the upper and lower surfaces of the thumbs as well. The gauze should be positioned so that the trailing appendage or string exits the mouth and is easily grasped with Magill forceps in the event that the gauze is dislodged during the reduction.

•While having an assistant prevent movement of the head, 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 (figure 4).

Alternatively, the clinician may stand behind the patient who is seated in a chair and then proceeds as follows [8]:

•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.

•Brace the patient's head against your abdomen.

•Apply downward force with the thumbs and then apply upward pressure with the fingers on the chin.

•If difficulty with reduction is encountered, the clinician may choose to rock the mandible back and forth to facilitate muscle fatigue, or while attempting reduction have the patient open wider, which will relax the masseter and temporalis.

●Wrist pivot – With this technique, the clinician faces the patient and grasps the mandible with the thumbs together under the chin (mentum) and fingers on the occlusal surfaces of the lower molars (figure 5) [14].

Next, upward force is applied with the thumbs and downward pressure is provided by the fingers. Force must be applied equally at all sites to avoid mandibular fracture. The clinician then pivots both wrists forward, which reduces the dislocation. Successful reduction by this technique in one case after failure of the traditional approach despite sedation has been described [14].

●Supine position technique – This technique attempts reduction with the patient in the supine position and the provider seated in a chair behind the patient's head. After thoroughly suctioning secretions from the mouth, the provider applies caudal thumb pressure on the anterior edge of the ascending ramus on both sides of the jaw rather than the occlusive surfaces while the remaining fingers of both hands grasp the mandible (picture 2).

In one trial of 40 patients, the majority with bilateral TMJ dislocation, the supine position technique was faster and less painful than the traditional technique [20]. However, both techniques successfully reduced the dislocation in all patients.

Extraoral technique — The extraoral reduction technique is another option if the syringe or intraoral technique fails. This technique requires firm pressure on the mandibular angle, which is usually painful, but has the advantage of not requiring the clinician to place fingers or thumbs in the mouth during reduction as follows (figure 6) [15]:

●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. At this point, the other side usually reduces spontaneously.

In a case series of seven patients who had failed initial attempts at TMJ dislocation reduction, including six individuals with bilateral dislocations, this technique was successful in all patients without the need for sedation or general anesthesia [15].

ADDITIONAL CARE AND FOLLOW-UP — After successful reduction of a TMJ dislocation, patients may warrant radiographs to ensure adequate reduction and to exclude an avulsion fracture. If available, a panoramic radiograph of the jaw is preferred to plain films of the jaw. Radiographs may be omitted in skeletally mature patients if the jaw feels back in place, dental occlusion is normal, and jaw movement does not cause significant pain.

Following reduction, the patient should receive the following instructions [3,4,8]:

●Avoid extreme opening of the jaw for three weeks. In some patients, placement of a padded rigid cervical collar (eg, Miami-J or Aspen cervical collar) may facilitate this instruction [21].

●Support the lower jaw when yawning.

●Apply warm compresses to the TMJ area for 24 hours.

●Maintain a soft diet for one week.

●Take nonsteroidal anti-inflammatory agents (eg, ibuprofen) as needed for pain and swelling.

●Undergo evaluation by oral and maxillofacial surgery in two to three days.

RECURRENT DISLOCATIONS — Patients with recurrent dislocation may be helped initially with the application of a Barton bandage after reduction (an elastic bandage or sling that wraps around the top of the head and mandible). In addition, intermaxillary fixation with wire and elastics may be necessary. Mandibular dislocation that persists or recurs despite fixation often leads to frequent emergency department visits. This problem may create suspicion of malingering or drug-seeking behavior on the part of the patient but may also indicate the presence of an orofacial movement disorder (oromandibular dystonia) involving the lateral pterygoid muscle on one or both sides [22].

Therapies for recurrent dislocation depend upon the precipitating anatomic mechanism and may include the use of sclerosing agents, maxillomandibular fixation, injection of botulinum toxin into the lateral pterygoid muscles, and surgery (eminectomy or eminoplasty) [1,3,10,11,23,24].

SUMMARY AND RECOMMENDATIONS

●Anatomy – Temporomandibular joint (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 (figure 1 and figure 2). (See 'Anatomy' above.)

●Etiology – TMJ dislocation commonly follows extreme opening of the mouth (eg, eating, yawning, laughing, singing, vomiting, dental treatment) and is less often caused by trauma or excessive muscle contraction from a dystonic reaction, seizure, or tetanus. (See 'Epidemiology and risk factors' above.)

●Clinical features – Clinical features of TMJ dislocation include trismus with the mouth open widely in the midline (bilateral dislocation) or deviated to the unaffected side (unilateral dislocation), a depression in the preauricular area, spasm of the muscles of mastication, and prominent and palpable mandibular coronoid processes just below the maxilla (image 1). (See 'Clinical features' above.)

●Diagnosis and imaging – The diagnosis of TMJ dislocation is made based upon clinical findings. All children and most adult patients with nontraumatic TMJ dislocation should also undergo panoramic jaw radiographs or mandibular computed tomography (CT) to exclude a mandibular fracture. Whenever possible, panoramic jaw radiographs are preferred in children because of lower radiation exposure. Skeletally mature patients with no trauma mechanism, typical clinical findings of TMJ dislocation, and no other clinical findings suggestive of fracture may undergo reduction without radiographs if obtaining radiographs poses an undue delay in reduction. (See 'Diagnosis' above.)

All patients with a possible jaw dislocation in the setting of facial trauma warrant CT of the face to fully assess for associated fractures and other injuries. (See 'Diagnosis' above.)

●Indications for specialty consultation – The following patients should undergo prompt referral to an oral and maxillofacial surgeon (see 'Indications for subspecialty consultation or referral' above):

•Patients with an anterior TMJ dislocation in association with a fracture.

•Patients who fail reduction of an anterior TMJ dislocation despite multiple attempts. Of note, clinicians who use the traditional intraoral method may be able to reduce the dislocation with an alternative technique (syringe method or extraoral technique). (See 'Reduction' above.)

•Patients who have had more than two prior TMJ dislocations.

•Patients with superior or posterior dislocations.

●Technique - For patients with TMJ dislocation, we suggest reduction using the syringe technique first because it does not require placement of the finger or thumbs on the occlusal surfaces of the molars and may be accomplished quickly without sedation (Grade 2C). However, the clinician should use the technique with which they are most comfortable. (See 'Approach' above.)

The methods of TMJ dislocation reduction are described above and include:

•Syringe method (picture 1) (see 'Syringe method' above)

•Traditional intraoral (figure 4), wrist pivot techniques (figure 5), or supine position techniques (picture 2) (see 'Intraoral technique' above)

•Extraoral technique (figure 6) (see 'Extraoral technique' above)

Reduction without sedation may be possible using the syringe, wrist pivot, or extraoral technique; sedation and analgesia is advised prior to attempting reduction with the traditional intraoral technique. (See 'Preparation' above.)

After successful reduction of a TMJ dislocation, patients may warrant radiographs to ensure adequate reduction and exclusion of an avulsion fracture. If available, a panoramic radiograph of the jaw is preferred to plain films of the jaw. Radiographs may be omitted in skeletally mature patients if the jaw feels back in place, dental occlusion is normal, and jaw movement does not cause significant pain.

●Aftercare – Aftercare instructions include a soft diet, local measures to manage pain, avoidance of extreme jaw opening, and evaluation by an oral and maxillofacial surgeon two to three days after reduction. (See 'Additional care and follow-up' above.)