European randomized controlled trial evaluating differential target multiplexed spinal cord stimulation and conventional medical management in subjects with persistent back pain ineligible for spine surgery: 24-month results

Abstract

Background: Differential target multiplexed spinal cord stimulation (DTM SCS) was shown to be superior to conventional SCS for treating chronic low back pain (CLBP) in subjects with persistent spinal pain syndrome with previous spinal surgery (PSPS-T2) or ineligible for it (PSPS-T1). This study reports 24-month efficacy and safety of DTM SCS vs. conventional medical management (CMM) in PSPS-T1 subjects across four European countries.

Methods: This is a prospective, multicenter, open-label, randomized, controlled trial with optional crossover. Subjects randomized 1:1 to DTM SCS or CMM. Primary endpoint was responder rate (% subjects reporting ≥50% CLBP relief) at 6 months. A superiority test compared responder rates between treatments. CLBP and leg pain levels, functional disability, quality of life (QoL), patient satisfaction and global impression of change were evaluated for 24 months. A Composite Responder Index (CRI) was obtained using CLBP relief, disability and QoL. Incidence of study-related adverse events evaluated safety.

Results: A total of 55 and 57 subjects were randomized to DTM SCS and CMM respectively. DTM SCS was superior, with CLBP responder rates ≥80% and CLBP relief >5.6 cm (>70% reduction) through the 24-month follow-up. Improvements with DTM SCS in other outcomes were sustained. The CRI was >80% for DTM SCS through 24 months. Opioid medication intake decreased in subjects treated with DTM SCS. Most patients treated with DTM SCS felt satisfied and improved at the end of the study. Safety was congruent with other studies.

Conclusion: DTM SCS is efficacious and safe during 24 months for the treatment of CLBP and leg pain in PSPS-T1 patients ineligible for spine surgery.

Significance statement: This randomized controlled trial shows that Differential Target Multiplexed SCS (DTM SCS) is an effective and safe long-term treatment for PSPS type 1 patients suffering from axial low back pain with or without leg pain and who are ineligible for spinal surgery. Currently, CMM treatments are their only option and provide limited benefits. Besides superior pain relief, DTM SCS provides significant improvements in functional disability, quality of life, high levels of satisfaction and perceived impression of change.