Long-term outcome of spinal cord stimulation for chronic pain management

Study Design. This is a retrospective study on 102 patients subjected to implantation of a spinal cord stimulation system for nonmalignant chronic pain management. The study was conducted through an extensive questionnaire and telephone interviews by a neutral third party. All the patients were implanted with a complete spinal cord stimulation system without a preliminary trial with a temporarily implanted electrode. Diagnostic categories were neuropathic pain,failed back syndrome, spinal cord injury pain, and miscellaneous. Average follow-up was 3.8 years (6 months to 8 years). Patients were divided in two groups: all the implanted patients in the survey (Group A) and the implanted patients who experienced some degree of pain relief with the stimulation (Group B). Group B (80 patients) closely matches previously published series where an initial temporary screening was performed. Results. Twenty-one,percent of the patients never experienced any pain relief. Of the remaining 80, 75% were still using the stimulator. Fifty-one percent of the 80 patients were experiencing good to excellent results and 20% moderate results. There was no reduction over time in the amount of pain relief in patients who initially had at least 75% pain relief. Patients with initial pain relief between 50% and 74% observed a moderate reduction in their pain relief after two years. Patients who initially experienced less than 50% pain relief observed a dramatic reduction in their results in the long term followup. Psychological screening contributed to the success of the procedure. Conclusions. With proper medical and psychological screening and with demonstrated initial pain relief, spinal cord stimulation remains an effective modality in the long-term management of severe chronic pain.