Long-term EVOKE™ Therapy Outcomes in Same Day Objective SCS Trial Responders: 12-month Results

Introduction: Traditional Open-Loop (OL) spinal cord stimulation (SCS) trials typically last 3-7 days, and success is defined by 50% reduction in pain symptoms based on subjective patient feedback. Prolonged OL-SCS trials may expose patients to higher risk of infections (1), lead migrations (2), and increase associated patient burden. Prognostic value and cost-effectiveness of SCS trials have also been questioned (3,4). The TRIAL-STIM RCT showed no evidence that a screening trial provides superior patient outcomes (4). EVOKE™ Therapy through evoked compound action potential (ECAP)-controlled closed-loop (CL) SCS allows objective confirmation of therapeutic neural activation (5) immediately post-programming, potentially enabling a same-day trial evaluation scenario. Previously, we reported the 3-month outcomes for same day responders whose leads were pulled on the same day as the trial procedure after experiencing physiologic ECAP-controlled CL-SCS. Herein, we report the 12-month outcomes.

Methods: Participants with chronic, intractable trunk and/or limb pain were enrolled in the prospective, multicenter ECAP study (NCT04319887). For a subset of patients, leads were pulled on the same day as the trial procedure after an objective trial evaluation was performed (Day0 Trial). During the trial evaluation, neural activation, and ability to maintain stable closed-loop EVOKE™ Therapy were objectively confirmed in addition to collection of patient-reported pain relief, functional improvement in various postures, and willingness to proceed to permanent implant. We report the 12-month outcomes of Day0 Trial patients from a single center.

Results: Day0 Trial patients (N=11) had robust 12-month outcomes: 82% responders (≥50% VAS reduction) and 64% high-responders (≥80% VAS reduction) with average pain reduction from baseline of 80%. Patients reported high satisfaction with therapy and pain relief and improvement on Patient Global Impression of Change (100% of patients “satisfied” or “very satisfied” and “much improved” or “very much improved (Table 1). Neural metrics calculated from individualized patient data were within the ranges shown to produce maximal analgesic benefit (Table 2) [6].

Conclusion: Robust 12-month outcomes for patients whose leads were pulled after an objective trial evaluation provide confidence in Day0 Trials and highlight the potential of Day0 Trials conducted with EVOKE™ Therapy for predicting long-term responders. Day0 Trials may be especially beneficial for patients using anti-coagulants and for reducing trial complication rates associated with extended trials. EVOKE™ Therapy may provide objective data to improve prognostic ability of traditional SCS trials in predicting outcomes and reducing associated patient burden. Permanent phase outcome comparisons between patients who experienced a Day 0 Trial versus a traditional trial are underway.