Electromyography in craniomaxillofacial trauma

Electromyography is used in conjunction with clinical diagnosis to determine the presence and extent of craniofacial injuries; it is also an aid in prognosis of recovery. This article reviews the neural pathophysiology following trauma and the basic principles of electrodiagnostic testing; such understanding helps to determine indications for electrodiagnostic testing.

Electrodiagnostic techniques can detect and differentiate the degree of injury. There are three major categories of nerve injury--neurapraxia, axonotmesis, and neurotmesis. In neuropraxic injuries, stimulation distal to the lesion will continue to elicit a response indefinitely; in more severe injuries, axonal degeneration begins within 3 to 5 days postinjury.

Electromyography may be used as a valuable adjunct to traditional forms of diagnosis and prognosis. The accuracy of electrodiagnostic data reported in the literature ranges from 50% to 67% in some studies and 77% to 90% in others. Studies with larger patient populations and longer follow-up periods are required.