Treatment of chronic pain by epidural spinal cord stimulation: a 10-year experience

Abstract

Epidural spinal cord stimulation by means of chronically implanted electrodes was carried out on 121 patients with pain of varied benign organic etiology. In 116 patients, the pain was confined to the back and lower extremities and, of these, 56 exhibited the failed-back syndrome. Most patients were referred by a pain management service because of failure of conventional pain treatment modalities. Electrodes were implanted at varying sites, dictated by the location of pain. A total of 140 epidural implants were used: 76 unipolar, 46 Resume electrodes, 12 bipolar, and six quadripolar. Patients were followed for periods ranging from 6 months to 10 years, with a mean follow-up period of 40 months. Forty-eight patients (40%) were able to control their pain by neurostimulation alone. A further 14 patients (12%), in addition to following a regular stimulation program, needed occasional analgesic supplements to achieve 50% or more relief of the prestimulation pain. Pain secondary to arachnoiditis or perineural fibrosis following multiple intervertebral disc operations, when predominantly confined to one lower extremity, seemed to respond favorably to this treatment. Uniformly good results were also obtained in lower-extremity pain secondary to multiple sclerosis. Pain due to advanced peripheral vascular disease of the lower limbs was well controlled, and amputation below the knee was delayed for up to 2 years in some patients. Pain due to cauda equina injury, paraplegic pain, phantom-limb pain, pure midline back pain without radiculopathy, or pain due to primary bone or joint disease seemed to respond less well. Patients who responded to preliminary transcutaneous electrical nerve stimulation generally did well with electrode implants. Notable complications included wound infection, electrode displacement or fracturing, and fibrosis at the stimulating tip of the electrode. Three patients in this series died due to unrelated causes. Epidural spinal cord stimulation has proven to be an effective and safe means of controlling pain on a long-term basis in selected groups of patients. The mechanism of action of stimulation-produced analgesia remains unclear; further studies to elucidate it might allow spinal cord stimulation to be exploited more effectively in disorders that are currently refractory to this treatment modality.

Spinal cord stimulation in chronic pain syndromes

“…Kumar, 33 Richardson 34 and Cole et al 37 could not demonstrate good e ects, although results of Richardson's study are possibly distorted by the fact that only one patient out of 10 had paresthesia in the pain region, which is, as formerly mentioned, essential for good results. Barolat 35 found pain due to spinal cord injury by far the worst responder of the chronic pain syndromes he had studied.…”

“…The possible advantage of extended trial periods should however been weighted against the higher infection rate associated with percutaneous trials. 22 When patients are considered to be candidates for SCS therapy, there must be an objective basis for the pain complaints, 33,69 and, as mentioned before, the integrity of the ®bres to be stimulated must be guaranteed.…”

Electrical Stimulation and Motor Recovery

“…Epidural spinal cord stimulation has long been used to treat intractable pain in patients (29,111,116,145,146,149,177,183,188,227,230). Sayenko et al (220) showed that lumbosacral epidural stimulation activated widespread rostral and caudal areas of the lumbar spinal cord, involving afferent and efferent pathways, in a patient with chronic SCI.…”

Neuropathic pain in patients with spinal cord injury: report of 213 patients

“…The positioning of the spinal electrode should be precise in order to allow for overlap of the pain area during trial stimulation. This fact has been shown to be important for long-term efficacy of spinal cord stimulation (SCS) 24,25 . The SCS appears to be most effective in patients with impartial and postcordotomy pain 5 .…”