Chronic dorsal column stimulation via percutaneously inserted epidural electrodes. Preliminary results in 31 patients

31 patients suffering from intractable pain associated with chronic low back syndrome, terminal cancer, and other disorders have been studied after an average 6 months' treatment by electrical stimulation of the spinal cord applied via electrodes inserted through a Tuohy needle into the epidural space. As judged by three different subjective rating methods, epidural stimulation successfully relieved otherwise intractable chronic pain in from 23 to 26 of the 31 patients. Reported improvements in the ability to perform various everyday activities, and elimination of drug usage by many patients, corroborate this finding. The side effects of stimulation, both as reported subjectively and as measured objectively by sensory testing, were not clinically significant. Spontaneous electrode displacements, leading to loss of analgesia and requiring minor surgery for repositioning, were encountered frequently, as were lead wire failures necessitating replacement. The partially implanted, externally powered stimulation system presently in use also suffers from problems of reliability and convenience to the patient.