Closed-Loop SCS System Approved for Chronic Intractable Pain

The Food and Drug Administration (FDA) has approved the Evoke® Spinal Cord Stimulation (SCS) System for the treatment of chronic intractable pain of the trunk and/or limbs, including unilateral or bilateral pain associated with failed back surgery syndrome, intractable low back pain, and leg pain.

Evoke is a novel, closed-loop SCS system that instantaneously reads, records, and responds to evoked compound action potentials (ECAPs), a measure of spinal cord fiber activation that generates pain inhibition for an individual. The Evoke System is capable of adjusting therapy more than 100 times per second to maintain optimal pain inhibition and stay within the preferred range of therapy. 

The approval was based on data from the prospective, multicenter, randomized, double-blind EVOKE study ( Identifier: NCT02924129), which compared the efficacy and safety of the Evoke SCS System to an open-loop SCS in 134 adults with chronic pain of the trunk and/or limbs. The primary endpoint was the proportion of patients with composite endpoint success, defined as a reduction in overall trunk and limb visual analog scale (VAS) pain score of 50% or more and no increase in baseline pain medication.

Findings demonstrated that the EVOKE SCS System was superior to open-loop stimulation for pain relief at 3 months (P =.005) and 12 months (P =.006). At 3 months, 82.3% (n=51/62) of the EVOKE arm and 60.3% (n=38/63) of the open-loop arm met the criteria for success. At 12 months, 83.1% (n=49/59) of patients implanted with EVOKE achieved the primary endpoint compared with 61.0% (n=36/59) of the open-loop group. Evoke also maintained spinal cord activation within the therapeutic window 95.2% of the time compared with 47.9% of the time for open-loop SCS.

“The groundbreaking technology behind the Evoke System’s ability to intelligently measure spinal cord activation has had many of us excited for a long time,” said Nagy Mekhail, MD, PhD, Professor at the Cleveland Clinic Lerner College of Medicine, Director of Evidence-Based Pain Medicine Research and Education in the Department of Pain Management at the Cleveland Clinic, and lead author and medical monitor for the EVOKE Study. “More exciting than the technology, though, is the unparalleled quality of the evidence backing this system which demonstrates pain relief coupled with clinically significant improvements in physical and emotional functioning, sleep quality, and health-related quality of life.”

Long-term data recently published in JAMA Neurology also showed that the EVOKE SCS System continued to provide superior pain relief at 24 months vs the open-loop SCS.

Saluda Medical plans to implement a controlled, limited release of the Evoke System in the second half of 2022 prior to initiating a full release in 2023.


  1. Saluda Medical receives FDA approval for the Evoke® Spinal Cord Stimulation System to treat chronic intractable pain. News release. Saluda Medical Pty Limited. Accessed March 8, 2022.
  2. Saluda Medical Evoke® SCS System. Summary of Safety and Effectiveness Data. Accessed March 8, 2022.