Repair of electrically injured median nerve with the aid of somatosensory evoked potential.

Abstract

In repair of the high voltage electrical injuries of peripheral nerve, selection of the proper plane for nerve coaptation after debridement is important since the electrical current is inclined to pass through the nerve trunks due to the lower electric resistance. In this report, we present our experience on use of the somatosensory evoked potentials (SSEP) test to assist determination of range of the injured nerve debridement in the electrical injured nerve. From January 1997 to December 2007, 30 patients with the high voltage electrical injury in the wrist, having defect of median nerve, were treated with nerve grafting. In 18 patients, the nerve resection plane was selected with the assistance of SSEP. In 12 patients, the nerve resection plane was determined by the traditional gross examination. The average lengths of nerve defect after debridement were 10.4 cm in the procedure with SSEP assistance and 4.01 cm in the traditional procedure. The finger motion was reconstructed by the tendon graft connecting the proximal forearm muscle and the distal tendon of flexor disitorum profundus. In following up, the two-point discrimination of finger was examined. The grade of finger sensory recovery was found improved in the patients who underwent the nerve repair with SSEP assistance than that in the patients underwent treatment with the traditional method. The results suggested that aggressive debridement is recommended for the high with voltage electrical nerve injury. SSEP could be a valuable tool for determination of the range of nerve debridement.