Dorsal column stimulation in pain treatment.

Thirty-five patients with chronic pain were treated by electrical stimulation of the dorsal columns through implanted epidural electrodes. In 5, such stimulation had minimal pain-reducing effect during an immediate postoperative trial period, and the electrodes were removed. In the remaining 30, an electrode system for chronic stimulation was implanted. Four of these died of related or unrelated causes. The electrode system was removed in 2 patients due to infections, and in 1 due to mechanical discomfort. The remaining 23 patients answered a questionnaire concerning the pain reducing effect of stimulation (4-60 months postoperatively, median 15 months). The group as a whole estimated the pain reducing effect of stimulation as weak. Only 10 patients (43.5%) used the stimulator regularly. Even in these patients, the pain-reducing effect was limited. Chronic back pain after repeated back surgery responded relatively better to stimulation than did the other cases. Phantom limb pain was most resistant. The modest results suggest future restriction on the use of such stimulation.