Long-term pain control by direct peripheral-nerve stimulation.

In 1970, we began implanting electrodes for prolonged stimulation of injured peripheral nerves to reduce chronic pain. Thirty-eight peripheral nerves in thirty-five patients have been stimulated with electrodes for a period ranging from four to nine years. Nineteen electrode systems were implanted in the upper extremity (eleven on the median nerve, six on the ulnar nerve, one on the median and ulnar nerves, and one on the median and radial nerves), with successful relief of pain in 52..6 per cent of the patients. Sixteen stimulators have been implanted on the sciatic nerve with a success rate for pain relief of 31 per cent. Failures in the lower extremity were found primarily in lesions of the posterior tibial nerve at the ankle. We speculate that the stress of weight-bearing and the anatomical position of the posterior tibial nerve may partially account for this rate of failure. Use of the electrode-implant systems required careful preoperative assessment by an experienced team, meticulous technique, and a mechanical system that tolerates stress. The location and characteristics of the lesion affect the response to electrical stimulation.