THE EFFECTS OF SPINAL CORD STIMULATION IN NEUROPATHIC PAIN ARE SUSTAINED: A 24-MONTH FOLLOW-UP OF THE PROSPECTIVE RANDOMIZED CONTROLLED MULTICENTER TRIAL OF THE EFFECTIVENESS OF SPINAL CORD STIMULATION

OBJECTIVE: After randomizing 100 failed back surgery syndrome patients to receive spinal cord stimulation (SCS) plus conventional medical management (CMM) or CMM alone, the results of the 6-month Prospective Randomized Controlled Multicenter Trial of the Effectiveness of Spinal Cord Stimulation (i.e., PROCESS) showed that SCS offered superior pain relief, health-related quality of life, and functional capacity. Because the rate of crossover favoring SCS beyond 6 months would bias a long-term randomized group comparison, we present all outcomes in patients who continued SCS from randomization to 24 months and, for illustrative purposes, the primary outcome (>50% leg pain relief) per randomization and final treatment. METHODS: Patients provided data on pain, quality of life, function, pain medication use, treatment satisfaction, and employment status. Investigators documented adverse events. Data analysis included inferential comparisons and multivariate regression analyses. RESULTS: The 42 patients continuing SCS (of 52 randomized to SCS) reported significantly improved leg pain relief (P < 0.0001), quality of life (P <= 0.01), and functional capacity (P = 0.0002); and 13 patients (31%) required a device-related surgical revision. At 24 months, of 46 of 52 patients randomized to SCS and 41 of 48 randomized to CMM who were available, the primary outcome was achieved by 17 (37%) randomized to SCS versus 1 (2%) to CMM (P = 0.003) and by 34 (47%) of 72 patients who received SCS as final treatment versus 1 (7%) of 15 for CMM (P = 0.02). CONCLUSION: At 24 months of SCS treatment, selected failed back surgery syndrome patients reported sustained pain relief, clinically important improvements in functional capacity and health-related quality of life, and satisfaction with treatment.