Diagnostic value of electrophysiological tests in patients with sciatica

OBJECTIVES: To assess the diagnostic value of electrophysiological tests in patients with sciatica. MATERIALS AND METHODS: The diagnostic value of electrophysiological tests were evaluated in 25 patients with monoradicular sciatica. The electrophysiological study included dermatomal somatosensory evoked potentials, electromyography, F-wave latencies, H-reflexes and motor and sensory nerve conduction determinations. The results of the electrophysiological examinations were evaluated blindly, and the test results were analysed separately by a receiver operating characteristic (ROC) analysis. Furthermore, the 5 modalities were evaluated jointly and analysed by a decision-analytic regret function. RESULTS: A high predictive value was found for the H-reflex examination, but low for the other modalities. When the 5 modalities were evaluated jointly, a non-significant decrease in expected regret from the pre-test situation of 0.96 to a value of 0.93 in post-test situation was revealed. CONCLUSION: Electrophysiological testing is not sufficient as stand-alone examination in patients with sciatica.