Sciatic neuropathies--a retrospective review of electrodiagnostic features in 29 patients.

Sciatic neuropathy is an uncommonly diagnosed focal mononeuropathy. We reviewed the aetiology and electrodiagnostic features of 29 patients studied at the Neurodiagnostic Laboratory, Tan Tock Seng Hospital from January 1989 to April 1995. External nerve compression was the most common cause (38%) followed by trauma (21%). Other rare causes in this series included intragluteal injections, hip surgery and diabetic mononeuropathy while 24% had uncertain aetiology. Electrodiagnostic studies showed preferential involvement of the peroneal division in 51%. Axonal loss was found in 97%. We conclude that sciatic neuropathy often mimics distal peroneal nerve dysfunction and neurophysiological studies are essential for diagnosis. Furthermore, these studies are necessary for assessing prognosis in relation to axonal loss.