PROSPECTIVE, MULTICENTER STUDY OF SPINAL-CORD STIMULATION FOR RELIEF OF CHRONIC BACK AND EXTREMITY PAIN

Study Design. This prospective, multicenter study was designed to inve stigate the efficacy and outcome of spinal cord stimulation using a va riety of clinical and psychosocial outcome measures. Data were collect ed before implantation and at regular intervals after implantation. Th is report focuses on 70 patients who had undergone 1 year of follow-up treatment at the time of data analysis.Objectives. To provide a more generalizable assessment of long-term spinal cord stimulation outcome by comparing a variety of pain and functional/quality-of-life measures before and after management. This report details results after 1 year of stimulation. Summary of Background Data. The historically diverse methods, patient selection criteria, and outcome measures reported in the spinal cord stimulation literature have made interpretation and co mparison of results difficult. Although short-term outcomes are genera lly consistent, long-term outcomes of spinal cord stimulation, as dete rmined by prospective studies that assess multidimensional aspects of the pain complaint among a relatively homogeneous population, are not well established. Methods. Two hundred nineteen patients were entered at six centers throughout the United States. All patients underwent a trial of stimulation before implant of the permanent system. Most were psychologically screened. One hundred eighty-two patients were implan ted with a permanent stimulating system. At the time of this report, c omplete 1-year follow-up data were available on 70 patients, 86% of wh om reported pain in the back or lower extremities. Patient evaluation of pain and functional levels was completed before implantation and 3, 6, 12, and 24 months after implantation. Complications, medication us age, and work status also were monitored. Results. All pain and qualit y-of-life measures showed statistically significant improvement during the treatment year. These included the average pain visual analogue s cale, the McGill Pain Questionnaire, the Oswestry Disability Questionn aire, the Sickness Impact Profile, and the Beck Depression Inventory. Overall success of the therapy was defined as at least 50% pain relief and patient assessment of the procedure as fully or partially benefic ial and worthwhile. Using this definition, spinal cord stimulation suc cessfully managed pain in 55% of patients on whom 1-year follow-up is available. Complications requiring surgical intervention were reported by 17% (12 of 70) of patients, Medication usage and work status were not changed significantly. Conclusions. This prospective, multicenter study confirms that spinal cord stimulation can be an effective therap y for management of chronic low back and extremity pain. Significant i mprovements in many aspects of the pain condition were measured, and c omplications were minimal.