In the cooperative patient with a spontaneous nontraumatic anterior dislocation, the diagnosis is based upon clinical grounds. In other dislocations, radiographs may be needed to confirm clinical suspicion. In the setting of significant trauma, radiographs should be obtained to exclude fracture. The panoramic view usually demonstrates the pathology and excludes other mandibular injury. Specific jaw or TMJ films may be helpful. In the patient with more serious trauma, where there may be a superior dislocation or intracranial injury, a CT scan will provide more information.
The differential diagnosis of jaw dislocation includes mandibular fracture, traumatic hemarthrosis, acute closed locking of the TMJ meniscus, and TMJ dysfunction. 12 Treatment
Reduction may be attempted in closed anterior dislocations without fracture. Most attempts are made easier with analgesia. A short-acting intravenous muscle relaxant (e.g., midazolam) helps to decrease muscle spasm.11 Appropriate airway and hemodynamic monitoring is required. A systemic analgesic (e.g., narcotic) may also be considered. Conscious sedation has also been used successfully.10
Alternatively, local anesthetic can be placed into the joint capsule. 11 Using aseptic technique, a 21-gauge needle is placed into the preauricular depression just anterior to the tragus and 2 mL of 2% lidocaine is injected.12 (See Fig 232-1,)
There are two methods for reducing an anterior mandibular dislocation.12 The most commonly used technique requires the patient to be firmly seated, with the head against the wall or chair back, positioned so that the examiner's flexed elbow is at the level of the patient's mandible. Facing the patient, the examiner places his or her gloved thumbs in the patient's mouth, over the occlusal surfaces of the mandibular molars, as far back as possible. The fingers should curve beneath the angle and body of the mandible. Using the thumbs, the examiner applies pressure downward and backward. Slightly opening the jaw may help disengage the condyle from the anterior eminence. (See £19.232-2). When the dislocation is bilateral, it may be easier to relocate one side at a time. Some suggest that the examiner may wish to wear gauze over the thumbs for protection, should the mandible snap closed after reduction.12
FIG. 232-2. The temporomandibular joints in normal and dislocated positions, and positioning for mandibular relocation in a seated patient. Positioning for mandibular relocation in a recumbent patient.
The second technique requires the examiner, standing behind the recumbent patient, to place the thumbs on the molars and apply downward and backward pressure.12
If the reduction is successful, the patient should be able to close his or her mouth immediately. Postreduction radiographs are not usually required unless the procedure was difficult or traumatic or there is significant discomfort postprocedure.
Complications from the reduction itself are unusual but can include iatrogenic fracture or avulsion of the articular cartilage. 10 Disposition
Patients with dislocations that are open, superior, associated with fracture, that manifest any nerve injury, or that are unreducible by closed technique should be emergently referred to a head and neck or oral surgeon.
Following the successful reduction of an acute dislocation, patients are placed on a soft diet and cautioned against opening their mouths more than 2 cm for the following 2 weeks.11 They should be instructed to support the mandible with a hand when they yawn. Nonsteroidal analgesics may be required to manage initial discomfort.
In all dislocations, follow-up is recommended. In severe cases, intermaxillary fixation may be required to control jaw motion during healing. Chronic dislocations may require operative intervention.
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