Darria Long Gillespie
The temporomandibular joint (TMJ) consists of the head of the mandibular condyle as well as the articular tubercle and mandibular fossa of the temporal bone (Fig. 64.1) (1). The joint is held loosely by the TMJ capsule, which has a weak surface anteriorly—allowing the variety of movements required, but also the relative ease of dislocation (2,3). The muscles of mastication are divided into two groups: the temporalis, masseter, and internal pterygoid muscles elevate, retract, and close the mandible, while the suprahyoid, infrahyoid, and external pterygoids open and protrude (Fig. 64.2) (4).
FIGURE 64.1 Bony Anatomy. (Adapted from Bickley LS, Szilagyi P. Bates’ Guide to Physical Examination and History Taking. 8th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2003.)
FIGURE 64.2 Muscular anatomy. (Adapted from Bickley LS, Szilagyi P. Bates’ Guide to Physical Examination and History Taking. 8th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2003.)
CLINICAL PRESENTATION
Temporomandibular Myofascial Pain Dysfunction Syndrome (TMPDS): TMPDS is a neuromuscular disturbance, and its causes are debated. Contributing factors include anatomic abnormalities (congenital or traumatic), microtrauma from clenching/grinding, stress, and systemic arthritides (5,6,7,8). Recent research suggests that sleep bruxism is not a cause of TMPDS (9,10). However, increased clenching and grinding in times of stress contributes to TMPDS and triggers a cycle of muscle pain, dysfunction, and spasm (1,6). Patients who present to the ED are more commonly females in their 20s to 40s (1) and experience unilateral dull pain involving the TMJ, masseter, and temporalis muscles. Pain worsens throughout the day, as well as with chewing, and may refer to the supraorbital, cervical, and occipital regions. Patients may also complain of a “click” or sensation of catching with opening and closing of the jaw (7), although clicking alone without pain is inadequate to make the diagnosis of TMPDS.
The TMJ is vulnerable to all conditions that affect joints in the body, including arthritis, ankylosis, and neoplasm (1). TMPDS secondary to systemic arthritides presents with pain and crepitus in periods of exacerbation and remission. Pain in secondary TMPDS typically is greatest in the morning, presents in younger patients, and has greater severity and joint erosion.
Acute mandibular dislocation: The most common dislocation direction is anterior, in which the condyle is trapped anterior to the articular tubercle due to muscle spasm, prohibiting jaw closure. Posterior, superior, and lateral dislocations are rare and usually associated with severe trauma and other injuries. Dislocations are more commonly bilateral; in unilateral dislocation, the jaw deviates away from the dislocation.
Acute dislocations can be caused by a direct blow to the jaw, seizures or dystonic reactions, and most commonly, due to maximum opening (yawning, laughing, vomiting, dental procedures). Predisposing factors include a shallow fossa and congenital or traumatic weakness of the joint capsule and ligaments (3,11). Patients present with the mouth stretched wide open, are anxious and uncomfortable, and have garbled speech and drooling due to the inability to swallow or move the tongue appropriately. They report exquisite pain due to masseter spasm.
DIFFERENTIAL DIAGNOSIS
In any patient presenting with facial, jaw, or head pain, the differential diagnosis includes deep space infections (peritonsillar abscess, retropharyngeal abscess, Ludwig angina), odontogenic pain (abscess, caries, tooth fracture), otologic referred pain, zoster, temporal arteritis, trigeminal neuralgia, or parotid gland pathology. Neck and shoulder pain are often reported with TMPDS, and the differential may include other disorders such as referred pain from cardiac ischemia.
Although most cases of TMJ dislocation are clinically obvious, some may be confused with mandibular fracture or acute dystonia. Dislocations and fractures may coexist.
ED EVALUATION
The emergency physician should thoroughly examine the head and neck to evaluate the airway and rule out non-TMJ causes. Examination frequently reveals spasm and tenderness of the masseter externally and internal pterygoid intraorally. The joint itself can be palpated by placing a finger just anterior to the tragus, or in the external auditory meatus and pulling forward on the tragus (Fig. 64.3). Both muscle and joint examinations should be performed while the patient opens and closes the mouth. If this completely reproduces the patient’s pain or demonstrates clicking or crepitus, a TMJ disorder is the likely cause. In severe cases, the jaw deviates toward the affected side, with myofascial spasm and trismus limiting full mouth opening. Examination may show facial asymmetry (12).
FIGURE 64.3 Palpation of the TMJ via pressure on tragus from external auditory canal.
For patients with a question of mandibular dislocation, evaluate for signs of trauma, including mandibular deformity or missing teeth, and for sensory deficit at the chin or mouth. With anterior dislocation, there is often a prominent-appearing lower jaw, as well as a depression in the preauricular area representing the empty temporal fossa.
Imaging
Atraumatic, subacute, or chronic TMJ pain: In the absence of trauma, signs of dislocation, acute change in bite, or asymmetry, emergent imaging is rarely required (7).
Mandibular dislocation: Spontaneous anterior mandibular dislocations that have no history of trauma, no atypical findings, nor evidence of fracture may be reduced without imaging (13). Otherwise, a mandibular x-ray or panorex view should be taken to exclude fracture (14). If these are unavailable, or there is high suspicion of fracture or internal derangement, a CT scan should be obtained (15).
KEY TESTING
• Obtain mandibular x-ray, panorex, or CT in cases of suspected fracture, trauma, or atypical or non-anterior dislocation
ED MANAGEMENT
TMJ pain or dysfunction: Regardless of cause, TMJ syndrome is initially treated with a combination of 1 to 2 weeks of physiotherapy, moist heated compresses, a soft/pureed diet, and nonsteroidal pain medication (5). Prescription pain medication or muscle relaxants may be of use acutely.
Acute TMJ dislocation: Anterior TMJ dislocation can be reduced in the ED.
1. Relief of anxiety, pain, and spasm is crucial (14,3), and procedural sedation or adequate analgesia is required. The physician may consider intra-articular anesthetic injection into the TMJ (3).
2. The patient should sit upright with a firm support behind his head, putting the mandible at the height of the physician’s elbow (14).
3. Facing the patient, place both thumbs intraorally (Fig. 64.4) on either the mandibular ridge or over the occlusal surface of the molars, with fingers gripping the mandible. (CAUTION: Muscle spasm will cause the jaw to snap into place quickly, and thumbs should be protected with gauze wrapping and possibly tongue depressors). Alternative methods include standing behind the patient, using an external approach (16), or positioning the patient supine with the physician at the head of the bed.
FIGURE 64.4 Anterior dislocation and reduction technique. (From Fleisher GR, Ludwig S, Henretig FM, et al. Textbook of Pediatric Emergency Medicine. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2006.)
4. Apply downward pressure to free the condyles from the tubercle. Consider gently rocking from one side to another instead of bilateral pressure, or tilting the chin up while pushing down on the posterior mandible (3,2). Once freed from the tubercle, the mandible quickly snaps posteriorly in a C-shaped direction. Success is followed by an immediate ability to close the mouth, reduced pain, and sense of relief (3).
Complications of reduction are rare and include fracture, cartilage injury, or operator bite injury. Postreduction imaging is only necessary in a difficult reduction or in cases of severe pain during/after the reduction (13).
Posterior, lateral, superior, or open dislocations, as well as those with associated fractures or that the emergency physician cannot reduce will likely require further intervention and the emergent evaluation by an oral/maxillofacial surgeon.
CRITICAL INTERVENTIONS
• Rule out non-TMJ etiologies of pain and any signs of potential airway compromise.
• Provide adequate sedation and analgesia to facilitate reduction of TMJ dislocation.
DISPOSITION
Patients with TMPDS should be referred to a general dentist or periodontist for occlusive therapy or intra-articular steroid injections. Many patients will improve with supportive measures (5); most tend to have periods of exacerbation and remission.
After successful reduction of an anterior dislocation, patients should use nonsteroidal analgesic for pain control. For the 2 weeks following a TMJ dislocation, patients must be instructed to avoid opening of the mouth beyond 2 cm, eat a soft/pureed diet, apply warm compresses, and follow up with a dentist or maxillofacial surgeon.
Special attention should be paid to children with posttraumatic internal abnormalities of the TMJ, as they are at higher risk of asymmetry in facial growth (2,14,17).
Common Pitfalls
• Failure to carefully examine for infection or referred etiology of pain.
• Failure to identify mandibular fracture.
• Failure to provide adequate sedation and analgesia to facilitate TMJ reduction.
REFERENCES
1. Rotter BE. TMJ disorders. In: Flint PW, ed. Cummings Otolaryngology: Head and Neck Surgery. 5th ed. Philadelphia, PA: Mosby; 2010:1279–1286.
2. McKay MP Majersak RJ. Facial Trauma. In: Marx J, ed. Rosen’s Emergency Medicine. 7th ed. Philadelphia, PA: Mosby; 2009:323–336.
3. Chan TC, Harrigan RA, Ufberg J. Mandibular reduction. J Emerg Med. 2008;34:
435–440.
4. Moore KL, Dalley AF, eds. Clinically Oriented Anatomy. 4th ed. Philadelphia, PA: Wolters Kluwer; 1999.
5. Rantala MA, Ahlberg J, Suvinen TI, et al. Temporomandibular joint related painless symptoms, orofacial pain, neck pain, headache, and psychosocial factors among non-patients. Acta Ondontol Scand.2003;61:217–222.
6. Velly AM, Gornitsky M, Phillipe P. Contributing factors to chronic myofascial pain: A case control study. Pain. 2003;104:491–499.
7. Goddard Greg. TM disorders. In: Lalwani AK, ed. Current Diagnosis and Therapy in Otolaryngology. 3rd ed. New York, NY: McGraw-Hill; 2012:407–414.
8. De Souza RF, Lovato da Silva CH, Nasser M, et al. Interventions for the management of temporomandibular joint osteoarthritis. Cochrane Database Syst Rev. 2012;4:CD007261.
9. Raphael KG, Sirois DA, Janal MN. Sleep bruxism and myofascial temporomandibular disorders: A laboratory-based polysomnographic investigation. J Am Dent Assoc. 2012;143(11):1223–1231.
10. Manfredini D, Lobbezoo F. Relation between bruxism and temporomandibular disorders: A systematic review of literature from 1998 to 2008. Oral Surg Oral Med Oral Pathol Oral Radiol Endod.2010;109(6):e26–e50.
11. Shorey CW, Campbell JH. Dislocation of the temporomandibular joint. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2000;89:662–668.
12. Stallard TC. Emergency disorders of the ear, nose, sinuses, oropharynx, and mouth. In: Stone CK, Humphries RL, eds. Current Diagnosis and Treatment in Emergency Medicine. 7th ed. New York, NY: McGraw Hill; 2011:513–536.
13. Heitz CR. Face and jaw emergencies. In: Tintinalli JE, ed. Tintinalli’s Emergency Medicine. 7th ed. New York, NY: McGraw Hill; 2011:1557–1564.
14. Riviello RJ, Brown NA. Otolaryngologic procedures. In: Roberts JR, Hedges JR, eds. Clinical Procedures in Emergency Medicine. 5th ed. Philadelphia, PA: Saunders Elsevier; 2010:1213–1215.
15. Sinha VP, Pradhan H, Gupta H, et al. Efficacy of plain radiographs, CT scan, MRI, and ultra sonography in temporomandibular joint disorders. Natl J Maxillofac Surg. 2012;3(1):2–9.
16. Ardehali MM, Kouhi A, Meighani A. TMJ dislocation reduction technique: A new external method vs. traditional. Ann Plast Surg. 2009;63:176–178.
17. Defabianis P. Post-traumatic TMJ internal derangement: Impact on facial growth (findings in a pediatric age group). J Clin Pediatr Dent. 2003;27(4):297–303.