SOLIS RCT: 2-year Outcomes of SCS vs Medical Management in Surgery-naïve Back Pain Patients

Introduction: Non-surgical back pain (NSBP) poses a significant clinical and economic burden. Multimodal spinal cord stimulation (SCS) is increasingly recommended as a therapeutic option. The SOLIS randomized controlled trial (RCT) evaluates SCS versus conventional medical management (CMM) in NSBP patients implanted with a multimodal SCS system. Here, we present the results of the randomization period, and preliminary 24-month outcomes for the SCS group, the Crossover group, and all SCS-implanted patients.

Methods: SOLIS is a multicenter, prospective RCT (ClinicalTrials.gov: NCT04676022) comparing SCS+CMM to CMM-only in NSBP patients with chronic low back and/or leg pain and no prior spine surgery. Participants meeting inclusion criteria were randomized to one of two arms. The primary endpoint was pain responder rate (≥50% reduction without increased opioids) at 3 months. Afterward, SCS subjects continued therapy as needed, while CMM subjects could elect crossover. Those receiving SCS were implanted with a multimodal SCS system (WaveWriter Systems, Boston Scientific). Key inclusion criteria include diagnosis of chronic low back pain, with or without leg pain, for 6-months, and care of chronic pain for 90 days. Primary endpoint is responder rate (≥50% reduction in pain) with no increase in baseline opioid medications at 3-months following treatment activation. At 3-months post-activation, subjects in SCS arm continue using SCS therapy as needed, whereas CMM arm subjects can elect to crossover to receive SCS, out to 24-months.

Results: Among 128 randomized subjects (63 SCS+CMM, 65 CMM-only), 89.5% of SCS+CMM arm achieved ≥50% pain relief vs. 8.1% in CMM-only at 3 months. At 24 months (n = 79), the overall responder rate was 86%, and 65% were high responders (≥80% relief). Oswestry Disability Index improved by 28 points. Eighty-one percent reported much/very much improvement via Global Impression of Change. CMM crossover subjects (n = 43) achieved outcomes similar to initial SCS group. Data collection is still ongoing.

Conclusion: Data obtained in this RCT so far demonstrates utilization of multimodal SCS provides for superior outcomes when compared to use of CMM alone for treatment of non-surgical refractory back pain including delivering sustained pain relief, functional improvement, and enhanced quality of life over two years.