Neurophysiologic tests in diagnosis of nerve root compression caused by disc herniation.

Patients with lumboradicular pain syndromes with or without sensomotor symptoms and signs often present with discrepancies in clinical and neuroradiologic (magnetic resonance imaging, computed tomography, myelogram) findings that make it difficult to identify a particular nerve root responsible for the patient's complaints. However, two questions usually are discussed for patients with relative indications for surgery: 1) positive predictors for an operation: who are the good candidates for surgery?; and 2) which level or nerve root should be approached to perform minimally invasive surgery? When imaging and clinical findings are not in complete agreement, the surgeon may need additional tests to make important decisions regarding surgery. Neurophysiologic tests can provide such information. However, the surgeon's expectation cannot be satisfied fully because of unanswered questions related to sensitivity, specificity, and positive predictive value of a particular electrophysiologic study.