Electrical stimulation of the brain in treatment of chronic pain. Experience over 5 years.

Forty-eight patients underwent electrical stimulation of the brain for treatment of chronic pain between 1978 and 1983. Average pain duration prior to treatment was 4.5 years. Before selection for this procedure patients underwent pain treatment in a multidisciplinary pain center, intensive psychological and psychiatric evaluation, and assessment of pain responsiveness to intravenous administration of placebo, morphine, and naloxone. A total of 71 electrodes were placed in the 48 patients at a variety of stimulating targets, including the periaqueductal gray matter, periventricular gray matter, thalamus, and internal capsule. Seventy-two percent of patients experienced complete or partial pain relief. In addition, 59% of patients were able to discontinue narcotic usage. Twenty-five percent of patients returned to normal physical activities and another 33% showed marked improvement in functional capacity. Follow-up periods ranged from 2 to 60 months; with a mean follow-up period of 20 months. A variety of relatively minor complications occurred, but no mortality or permanent sequelae were experienced. No patient's pain was made worse as a result of electrical stimulation. Electrical stimulation of the brain offers a safe and relatively effective method for the treatment of chronic pain in appropriately selected patients, who are unresponsive to other forms of therapy.