ECAP-controlled closed-loop versus open-loop SCS for the treatment of chronic pain: 36-month results of the EVOKE blinded randomized clinical trial
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Published:2023-08-27
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Volume:
Page:rapm-2023-104751
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ISSN:1098-7339
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Container-title:Regional Anesthesia & Pain Medicine
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language:en
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Short-container-title:Reg Anesth Pain Med
Author:
Mekhail Nagy AORCID, Levy Robert M, Deer Timothy RORCID, Kapural Leonardo, Li Sean, Amirdelfan Kasra, Pope Jason E, Hunter Corey W, Rosen Steven M, Costandi Shrif JORCID, Falowski Steven M, Burgher Abram H, Gilmore Christopher A, Qureshi Farooq A, Staats Peter S, Scowcroft James, McJunkin Tory, Carlson Jonathan, Kim Christopher K, Yang Michael I, Stauss Thomas, Petersen Erika A, Hagedorn Jonathan MORCID, Rauck Richard, Kallewaard Jan W, Baranidharan Ganesan, Taylor Rod S, Poree Lawrence, Brounstein Dan, Duarte Rui VORCID, Gmel Gerrit E, Gorman Robert, Gould Ian, Hanson Erin, Karantonis Dean M, Khurram Abeer, Leitner Angela, Mugan Dave, Obradovic Milan, Ouyang Zhonghua, Parker John, Single Peter, Soliday Nicole
Abstract
IntroductionThe evidence for spinal cord stimulation (SCS) has been criticized for the absence of blinded, parallel randomized controlled trials (RCTs) and limited evaluations of the long-term effects of SCS in RCTs. The aim of this study was to determine whether evoked compound action potential (ECAP)-controlled, closed-loop SCS (CL-SCS) is associated with better outcomes when compared with fixed-output, open-loop SCS (OL-SCS) 36 months following implant.MethodsThe EVOKE study was a multicenter, participant-blinded, investigator-blinded, and outcome assessor-blinded, randomized, controlled, parallel-arm clinical trial that compared ECAP-controlled CL-SCS with fixed-output OL-SCS. Participants with chronic, intractable back and leg pain refractory to conservative therapy were enrolled between January 2017 and February 2018, with follow-up through 36 months. The primary outcome was a reduction of at least 50% in overall back and leg pain. Holistic treatment response, a composite outcome including pain intensity, physical and emotional functioning, sleep, and health-related quality of life, and objective neural activation was also assessed.ResultsAt 36 months, more CL-SCS than OL-SCS participants reported ≥50% reduction (CL-SCS=77.6%, OL-SCS=49.3%; difference: 28.4%, 95% CI 12.8% to 43.9%, p<0.001) and ≥80% reduction (CL-SCS=49.3%, OL-SCS=31.3%; difference: 17.9, 95% CI 1.6% to 34.2%, p=0.032) in overall back and leg pain intensity. Clinically meaningful improvements from baseline were observed at 36 months in both CL-SCS and OL-SCS groups in all other patient-reported outcomes with greater levels of improvement with CL-SCS. A greater proportion of patients with CL-SCS were holistic treatment responders at 36-month follow-up (44.8% vs 28.4%), with a greater cumulative responder score for CL-SCS patients. Greater neural activation and accuracy were observed with CL-SCS. There were no differences between CL-SCS and OL-SCS groups in adverse events. No explants due to loss of efficacy were observed in the CL-SCS group.ConclusionThis long-term evaluation with objective measurement of SCS therapy demonstrated that ECAP-controlled CL-SCS resulted in sustained, durable pain relief and superior holistic treatment response through 36 months. Greater neural activation and increased accuracy of therapy delivery were observed with ECAP-controlled CL-SCS than OL-SCS.Trial registration numberNCT02924129.
Subject
Anesthesiology and Pain Medicine,General Medicine
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