Spinal cord stimulation--a long-term evaluation in patients with chronic pain.

Spinal cord stimulation (SCS) is an established treatment modality for chronic pain, angina pectoris, and peripheral vascular disease. This study evaluates experience with SCS over a 13-year period with emphasis on surgical complications, revisions and pain relief. It took the form of a retrospective study of medical/surgical records coupled with a postal/telephone questionnaire. The subjects consisted of seventy patients, aged from 21 to 76 years (mean 47; median 46), with severe, chronic pain refractory to conventional treatment, who underwent SCS implantation between 1984 and 1997. It investigated surgical revisions, complications and pain relief. There were 72 surgical revisions comprising electrode replacement/repositioning (32), generator replacement (22), cable failure (6) and implant removal (12). Half the devices were revised within 3 years (95% confidence interval: 2-5 years) of implantation. Six (8.6%) implants became infected. Sixty per cent of patients reported substantial relief of pain. This study shows that the majority of patients undergoing SCS derive significant benefit in terms of pain relief, but commonly require surgical revisions due to both technical and biological factors. These devices require systematic evaluation to determine optimal usage, clinical effectiveness and cost-benefit analysis.