ECAP-Based SCS for the Treatment of Chronic Pain: evoke Study 36-Month Outcomes

BACKGROUND: INTRODUCTION: Utilization of objective neurophysiological measures to guide clinicians in providing optimal spinal cord stimulation (SCS) for chronic pain patients is a novel concept to neuromodulation. This clear and transparent mechanistic approach provides a better understanding to clinicians, patients, and payors allowing for proper evaluation of clinical outcomes. A novel SCS system delivers evoked‐compound action potentials (ECAPs)‐ based therapy to 1) Guide programming and confirm activation of the intended target (i.e., ECAP‐guided programming); and 2) Deliver closed‐loop therapy to maintain accurate and consistent neural activation on every stimulus (i.e., ECAP‐controlled closed‐loop SCS). AIMS: This therapy has now been studied in a 24‐month double‐blind randomized controlled trial (RCT) with self‐selected crossover through 36 months. ECAP‐based therapy enables real‐time collection of continuous, objective, in‐vivo neurophysiological data. This provides proper evaluation of the therapy and interpretation of the clinical outcomes, resulting in a level of evidence unmatched in neuromodulation. METHODS: The EVOKE RCT was designed to evaluate the safety and efficacy of ECAP‐based therapy to treat chronic back and leg pain (NCT02924129)1. Patients were randomized to open‐loop (OL) or ECAP‐controlled closed‐loop (CL) stimulation; both treatment groups received ECAP‐guided programming. Following the 24‐ month visit1, patients were allowed to participate in a self‐selected crossover phase which continued through the 36‐month visit. Overall, back and leg pain (VAS), opioid usage, and other patient‐reported clinical outcomes including physical (ODI) / emotional (POMS) functioning, sleep quality (PSQI), and quality of life (EQ‐5D) were collected. Additionally, objective neurophysiological data, including spinal cord activation were measured. RESULTS: Following the 24‐month visit, 62% OL vs. 32% CL blinded patients voluntarily crossed‐over to the other stimulation mode. At the end of the crossover, 89% of patients who were exposed to CL, remained in CL. In this presentation, 36‐month outcomes of Evoke study will be premiered in Europe. Durability of ECAP‐based therapy, including the safety profile, holistic treatment response, consistency/accuracy of delivered neural activation, crossover results, and associated neurophysiology will be presented. CONCLUSIONS: Data from the EVOKE study demonstrates that ECAP‐guided programming and ECAP‐controlled closed‐loop neural activation resulted in sustained, durable pain relief and holistic treatment response at 36 months. ECAP‐based therapy provides a transparent, objective approach to SCS by which therapy can be monitored and adjusted to improve patients' lives.