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ECAP-controlled closed-loop versus open-loop SCS for the treatment of chronic pain: 36-month results of the EVOKE blinded randomized clinical trial

2023; BMJ; Linguagem: Inglês

10.1136/rapm-2023-104751

1532-8651

Nagy Mekhail, Robert M. Levy, Timothy R. Deer, Leonardo Kapural, Sean Li, Kasra Amirdelfan, Jason E. Pope, Corey Hunter, Steven M. Rosen, Shrif Costandi, Steven Falowski, Abram H. Burgher, Christopher Gilmore, Farooq Qureshi, Peter S. Staats, James Scowcroft, Tory McJunkin, Jonathan D. Carlson, Christopher K. Kim, Michael Yang, Thomas Stauss, Erika Petersen, Jonathan M. Hagedorn, Richard Rauck, Jan Willem Kallewaard, Ganesan Baranidharan, Rod S Taylor, Lawrence Poree, Dan Brounstein, Rui Duarte, Gerrit Gmel, Robert B. Gorman, Ian Gopal Gould, Erin Hanson, Dean M. Karantonis, Abeer Khurram, Angela Leitner, Dave Mugan, Milan Obradović, Zhonghua Ouyang, John L. Parker, Peter Single, Nicole Soliday,

Myofascial pain diagnosis and treatment

Introduction The 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. Methods The 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. Results At 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. Conclusion This 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 number NCT02924129 .