Impact of Long-Term Evoked Compound Action Potential Controlled Closed-Loop Spinal Cord Stimulation on Sleep Quality in Patients With Chronic Pain: An EVOKE Randomized Controlled Trial Study Subanalysis

Objective: Spinal cord stimulation (SCS) is considered an effective interventional nonpharmacologic treatment option for several chronic pain conditions. Here we present the effects of the novel evoked compound action potential (ECAP) controlled closed-loop (ECAP-CL) SCS system on long-term sleep quality outcomes from the EVOKE study.

Materials and methods: The EVOKE study is a double-blind, randomized, controlled clinical trial conducted at 13 sites in the United States (N = 134 patients). The clinical trial utilized SCS to manage chronic pain and compared novel ECAP-CL technology to open-loop SCS. Additionally, sleep quality data was collected using the Pittsburgh Sleep Quality Index (PSQI) at baseline and all study visits.

Results: The mean PSQI global score for ECAP-CL patients at baseline was 14.0 (n = 62; ± 0.5, SD 3.8), indicating poor sleep quality. Clinically meaningful and statistically significant reductions (p < 0.001) in the global PSQI scores were noted at 12 months (n = 55; 5.7 ± 0.6, SD 4.2). A total of 76.4% of ECAP-CL patients met or exceeded Minimal Clinically Important Difference from baseline in PSQI at 12 months. Additionally, 30.9% of ECAP-CL patients achieved "good sleep quality" scores (PSQI ≤ 5), and 29.1% achieved sleep quality remission. "Normative" sleep scores were observed in 29.6% of ECAP-CL patients at 12 months, and these scores were better than the US general population. Additionally, ECAP-CL patients achieved statistically significant changes from baseline (p < 0.01) across all seven subcomponent scores of PSQI at 12 months.

Conclusions: ECAP-CL SCS elicits consistent neural activation of the target leading to less variability in long-term therapy delivery. In the EVOKE study, this resulted in ECAP-CL patients demonstrating clinically superior and sustained pain relief. Results from this study provide new evidence of long-term improvement in sleep quality and quantity in patients with chronic pain resulting from the use of this novel ECAP-CL SCS technology.

Clinical trail registration: The Clinicaltrials.gov registration number for the study is NCT02924129.