Acute dislocation of the temporomandibular joint (TMJ) is a relatively common occurrence; chronic long-term dislocation is rare. Variance in the duration of dislocation and anatomical considerations make the treatment for long-standing dislocation complex and controversial. This paper attempts to review the literature associated with chronic TMJ dislocation treatment options and presents the authors’ experience with a particularly long term dislocation.
Dislocation of the temporomandibular joint (TMJ) typically occurs when the mandibular condyle becomes displaced out of the glenoid fossa and anterior to the articular eminence, although rare reports also describe posterior, lateral, and superior dislocations. One or both mandibular condyles can be affected with the majority of cases occurring bilaterally. Some authors differentiate subluxation, as displacement of the condyle which can be self-reduced by the patient, and dislocation as displacement that cannot be reduced by the patient.
Dislocation of the TMJ is a fairly common condition which occurs for a variety of reasons. Predisposing and etiological factors for condylar dislocation include extreme mouth opening during yawning (46%), motor vehicle accidents and other trauma, dental treatments, medications, especially the anti-emetics metoclopramide and compazine which produce extra pyramidal effects, joint hypermobility associated with systemic diseases such as Ehlers–Danlos and Marfan syndromes, congenital joint weakness, intubation, and psychogenic and neurological disorders.
Classification of the dislocation can be divided into acute (most common), habitual, recurrent, and long-standing or chronic. No clear guidelines or standards have been set to define a duration distinguishing chronic from acute dislocation. Huang et al. suggest that chronic dislocation be defined as acute dislocation left untreated or inadequately treated for 72 h or more.
Most commonly, mandibular dislocation is an acute anterior dislocation and can be manipulated downward and backward into the glenoid fossa with or without local anaesthesia or sedation. Habitual or recurrent dislocation is repeated episodes of dislocation becoming more and more frequent and progressively worse. Long-standing or chronic dislocation is extremely rare, but causes significant discomfort and quality of life issues for the patient.
A 73-year-old otherwise healthy female was referred to the authors’ clinic with the chief complaint of inability to close her mouth. Four months prior to presentation, she recalled yawning and states she was unable to close her mouth afterward. She was fully edentulous with upper and lower complete dentures, and had no prior history of TMJ dislocation. At the time of dislocation, she presented to an outside hospital and was misdiagnosed as having had a stroke. She was admitted and a work up for cerebrovascular accident was performed and found to be negative. She was discharged still in open lock and went to see her general dentist. The dentist was unable to reduce her mouth opening and referred her to a maxillofacial surgeon. Owing to restrictions and limitations in her insurance plan, there were delays in presenting to the oral and maxillofacial surgeon. On presentation to the surgeon, she was diagnosed with anterior dislocation of the TMJ and unsuccessful attempts were made to reduce the open lock with local anaesthetic in the office and under general anaesthesia and muscle relaxants in the operating room. On presentation to the authors’ clinic she had been dislocated for 12 weeks. She complained of inability to masticate, swallow, and difficulty with speaking. She continued to wear her dentures, but the occlusion was significantly altered and non-functional.
She had complete maxillary and mandibular dentures, downward and forward displacement of the chin with significant anterior open bite. No palpable condyle in the pre-auricular region. Tenderness to palpation in the pre-auricular region was noted.
Radiologic examination was undertaken with a panoramic radiograph and computed tomography (CT). The panorex showed bilateral anteriorly displaced mandibular condyles well beyond the articular eminences ( Fig. 1 ). The CT confirmed the panoramic findings and also showed cupping of the lateral pole of the condyle consistent with pseudoarticulation with the zygomatic arch ( Fig. 2 ).
With the history provided, the authors again attempted unsuccessfully to reduce the dislocation with local anaesthesia in the office. At this point surgical intervention was indicated and discussed with the patient.
Once under general anaesthesia, manual attempts were made to reduce the condyles unsuccessfully. At that time, bilateral incisions were made with a periauricular approach to the TMJ. The glenoid fossas were found to be empty of the mandibular condyles and contained significant dense scar tissue. The condyles were found anterior to the eminence and medial to the zygomatic arch. The authors attempted to reposition the condyles manually to the original position; but owing to the dense fibrosis and masticatory muscle shortening, these attempts also failed.
A clinical decision was made at that time that the patient would require a condylectomy in order to reduce the mandible in its appropriate position. In consideration of the patients edentulism and the ramus shortening bilateral condylectomies would cause, the authors decided to reconstructed the TMJ with an alloplastic total joint prosthesis (Biomet Microfixation, Jacksonville, FL, USA). The condylectomies were performed and the patient was placed in intermaxillary fixation (IMF) utilizing her dentures to estabilish proper jaw relations ( Fig. 3 ). The ramus was accessed via a submandibular approach, and the fossa components and mandibular components were secured. The IMF was released and the occlusion was checked and found to be reproducible and stable with good range of motion. The patient was not left in IMF postoperatively.