New SCS System That Adjusts to Spinal Cord Responses Effectively Treats Chronic Pain

The results from 2 clinical studies by Saluda Medical evaluating the performance of the company’s Evoke® ECAP-Controlled, Closed-Loop Spinal Cord Stimulation (SCS) System were presented at the International Neuromodulation Society 14th World Congress, held May 25-30 in Sydney, South Wales, Australia.

Evoke is the first closed-loop SCS system that measures the spinal cord’s response to stimulation via evoked compound action potentials (ECAPs). The system adjusts on every pulse to maintain activation within the patient’s therapeutic window. The technology is designed to provide long-term relief from chronic pain, improve patients’ quality of life, and reduce dependency on pain medications.

There were 2 studies examining the efficacy of the Evoke system in patients with chronic pain: the Evoke study conducted in the United States was a 3 month-long double-blind randomized, designed to gain regulatory approval for the technology; and the Avalon study, an 18 month-long study conducted in Australia was a prospective single-arm study designed to examine the long-term effects of the system.

The Evoke study indicated statistically significant improvements in back and leg pain in patients treated with the closed-loop system vs participants in the control group (≥50% pain relief in 82.3% vs 60.3%, respectively, and ≥80% pain relief in 58.1% vs 42.9%, respectively), with comparable levels of analgesic medication use, and a greater percentage of patients in the Evoke vs control group receiving spinal cord stimulation in the therapeutic window (91.1% vs 59.5%, respectively).

A majority of patients in the Avalon study reported >80% pain relief (69.4%), clinically meaningful improvements in quality of life (83.3%), improvement in disability (minimal to moderate disability: 72.2% at 18 months vs 18.0% at baseline), reduction/elimination of opioid use (by 67.9% of participants), and the maintenance of spinal cord activation within therapeutic window for 97.5% of the time.

Clinical Pain Advisor talked with Steven M. Falowski, MD, director of functional neurosurgery at Neurosurgical Associates of Lancaster, Lancaster, Pennsylvania, and one of the investigators of the Evoke Study.

Clinical Pain Advisor: Results from the Evoke study indicate significant advantages associated with the use of a closed-loop system for SCS. In your view, what are some of the most remarkable benefits of this technology?

Dr Falowski: The Evoke data represent a tremendous advancement in our field. Using closed-loop SCS, we are no longer blindly stimulating the spinal cord or nerves. Instead, we are able to clearly see what is happening or how the patient is responding to this treatment.

Maintaining consistent stimulation within the therapeutic window has historically been a challenge. We know that each time the patient changes positions, the electrodes can get closer or farther away from the spinal cord. Even micro-movements completely change the amount of stimulation the nerves receive. However, a closed-loop system can still generate the same ECAP within the therapeutic window. The Avalon study revealed that spinal cord activation was maintained within the therapeutic window 97.5% of the time.