According to study results, evoked compound action potential-controlled closed-loop spinal cord stimulation compared with fixed-output, open-loop spinal cord stimulation offered significantly greater and more meaningful pain relief at 12 months in patients with chronic, intractable back and leg pain.
“The results of the U.S. Evoke pivotal trial published in the top neurology journal, The Lancet Neurology, are truly a game-changer for the field, as they show how this promising new type of therapy may benefit patients suffering with chronic pain,” Lawrence Poree, MD, MPH, PhD, director of the neuromodulation service in the division of pain medicine at University of California, San Francisco and the senior author of the study, told Healio/Orthopedics. “Evoke is designed to enable an interactive, mechanism-based, individualized therapy utilizing an objective outcome measure. Overall the study shows the advantage of closed-loop spinal cord stimulation, demonstrating robust, long-term evidence of outcomes in the treatment of overall pain — and not just a segment of pain —with high responder rates of more than 50% of patients achieving over 80% pain relief.”
At 13 specialist clinics, academic centers and hospitals, investigators performed a double-blind, randomized controlled trial of 134 patients with chronic, intractable back and leg pain who were on pain medication. Patients also had no prior experience with spinal cord stimulation. There were 67 patients who were assigned to receive evoked compound action potential-controlled closed-loop spinal cord stimulation and the other 67 patients received fixed-output, open-loop spinal cord stimulation. The proportion of patients with a 50% decrease or greater in the overall back pain and leg pain without an increase in pain medications was the primary study outcome. Investigators tested noninferiority and superiority in 125 intention-to-treat patients at 3 months after permanent implant and in 118 patients at 12 months after permanent implant.
Results showed more patients in the closed-loop spinal cord stimulation group achieved the primary outcome vs. the open-loop group (82.3% vs. 60.3%) at 3 months and at 12 months (81.3% vs. 61%).
According to researchers, there was no difference seen among the treatment groups with regard to safety profiles. Investigators noted the most frequently seen adverse events included lead migration, implantable pulse-generator pocket pain and muscle spasm or cramp.
“In addition, this double-blind randomized control trial confirms the open label Australian Avalon study, again demonstrating that that the spinal cord response to stimulation can be successfully measured and used to adjust stimulation to maintain spinal cord activation within the patient-specific therapeutic window,” Poree said. “This controlled level of spinal cord activation provided by closed-loop technology was associated with increased pain relief and positive clinical outcomes in the study.” – by Monica Jaramillo
Disclosures: The researchers report no relevant financial disclosures.