Non-traumatic peroneal nerve palsy: MRI findings

AIM: To present magnetic resonance imaging (MRI) findings of non-traumatic peroneal nerve palsy and to evaluate the usefulness of MRI in patients with non-traumatic peroneal nerve palsy. MATERIALS AND METHODS: In a retrospective study, 11 consecutive patients presenting with peroneal nerve palsy were included. MR images of the tower leg and electrophysiological examinations were also reviewed. The cause of peroneal nerve palsy was determined on the basis of MR] findings and was evaluated using electrophysiological data. Nine patients with causative lesions detected on MRI, underwent surgery. RESULTS: Clinical examination and electromyography (EMG) disclosed 11 peroneal lesions. MR[ and EMG revealed three types of signal intensity change, i.e. deep peroneal nerve palsy type, common peroneal nerve palsy type, and superficial peroneal nerve palsy type. The MRI and EMG findings were in agreement in seven (65%) of the 11 study patients. In nine patients the causative lesions were identified using MRI, including ganglion cyst (n = 6), osteochondroma (n = 1), synovial cyst (n = 1), and aneurysm (n = 1). CONCLUSION: Ganglion cyst is the most common cause of non-traumatic peroneal nerve palsy. MRI offers a noninvasive method for obtaining useful information to assess, localize, and monitor peripheral peroneal nerve palsy. (C) 2006 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.