Pain suppression by peripheral nerve stimulation. Chronic effects of implanted devices

This is a study of the long range effects of pain suppression obtained by electrical stimulation of peripheral nerves. These cases were followed during 12--46 months and evaluated personally and by questionnaires. Selection for surgery was done exclusively on the basis of the results of a preoperative peripheral nerve stimulation test. Of 37 cases observations, 18 were considered significantly relieved; that is, more than 50% of the intensity and/or duration of pain was consistently admitted. The results obtained in the acute preoperative trial could be reproduced indefinitely in some cases for as long as 46 months. Correlation of the results with the disease producing the pain revealed as benefitting for painful syndromes associated with peripheral nerve disorders, amputation, soft tissue injuries (nerves?), and some recurrent lumbar disc surgeries. Sciatic, ulnar and occipital nerve implantations were particularly rewarding. The best and worse results were analyzed. The complications appear to be largely preventable and of no serious consequences. Our analysis suggests that most failures take place within 2 years from implantation. Experience seems to be accumulating showing that a number of patients may receive sustained relief beyond this period.