Durability of Evoked Compound Action Potential (ECAP)-Controlled, Closed-Loop Spinal Cord Stimulation (SCS) in a Real-World European Chronic Pain Population

Pain and Therapy, vol. 13, pp. 1119–1136

Abstract

INTRODUCTION: Closed-loop spinal cord stimulation (CL-SCS) is a recently introduced system that records evoked compound action potentials (ECAPs) from the spinal cord elicited by each stimulation pulse and uses this information to automatically adjust the stimulation strength in real time, known as ECAP-controlled SCS. This innovative system compensates for fluctuations in the distance between the epidural leads and the spinal cord by maintaining the neural response (ECAP) at a predetermined target level. This data collection study was designed to assess the performance of the first CL-SCS system in a real-world setting under normal conditions of use in multiple European centers. The study analyzes and presents clinical outcomes and electrophysiological and device data and compares these findings with those reported in earlier pre-market studies of the same system. METHODS: This prospective, multicenter, observational study was conducted in 13 European centers and aimed to gather electrophysiological and device data. The study focused on the real-world application of this system in treating chronic pain affecting the trunk and/or limbs, adhering to standard conditions of use. In addition to collecting and analyzing basic demographic information, the study presents data from the inaugural patient cohort permanently implanted at multiple European centers. RESULTS: A significant decrease in pain intensity was observed for overall back or leg pain scores (verbal numerical rating score [VNRS]) between baseline (mean ± standard error of the mean [SEM]; n = 135; 8.2 ± 0.1), 3 months (n = 93; 2.3 ± 0.2), 6 months (n = 82; 2.5 ± 0.3), and 12 months (n = 76; 2.5 ± 0.3). Comparison of overall pain relief (%) to the AVALON and EVOKE studies showed no significant differences at 3 and 12 months between the real-world data release (RWE; 71.3%; 69.6%) and the AVALON (71.2%; 73.6%) and EVOKE (78.1%; 76.7%) studies. Further investigation was undertaken to objectively characterize the physiological parameters of SCS therapy in this cohort using the metrics of percent time above ECAP threshold (%), dose ratio, and dose accuracy (µV), according to previously described methods. Results showed that a median of 90% (40.7-99.2) of stimuli were above the ECAP threshold, with a dose ratio of 1.3 (1.1-1.4) and dose accuracy of 4.4 µV (0.0-7.1), based on data from 236, 230, and 254 patients, respectively. Thus, across all three metrics, the majority of patients had objective therapy metrics corresponding to the highest levels of pain relief in previously reported studies (usage over threshold > 80%, dose ratio > 1.2, and error < 10 µV). CONCLUSIONS: In conclusion, this study provides valuable insights into the real-world application of the ECAP-controlled CL-SCS system, highlighting its potential for maintaining effective pain relief and objective neurophysiological therapy metrics at levels seen in randomized control trials, and potential for quantifying patient burden associated with SCS system use via patient-device interaction metrics. CLINICAL TRIAL REGISTRATION: In the Netherlands, the study is duly registered on the International Clinical Trials Registry Platform (Trial NL7889). In Germany, the study is duly registered as NCT05272137 and in the United Kingdom as ISCRTN27710516 and has been reviewed by the ethics committee in both countries.

Authors 14

1. Harold Nijhuis corresponding

   St. Antonius Ziekenhuis

   Affiliation as printed

   St. Antonius Hospital, Koekoekslaan 1, 3435 CM, Nieuwegein, Netherlands. h.nijhuis@antoniusziekenhuis.nl

   St. Antonius Hospital, Koekoekslaan 1, 3435 CM, Nieuwegein, Netherlands

2. Jan Willem Kallewaard

   Erasmus MC · Rijnstate Hospital

   Affiliation as printed

   Erasmus University Medical Center, Rotterdam, Netherlands

   Rijnstate Hospital, Velp, Netherlands

3. Johan van de Minkelis

   Elisabeth-TweeSteden Ziekenhuis

   Affiliation as printed

   Elisabeth-Tweesteden Hospital, Tilburg, Netherlands

4. Willem-Jan Hofsté

   St. Antonius Ziekenhuis

   Affiliation as printed

   St. Antonius Hospital, Koekoekslaan 1, 3435 CM, Nieuwegein, Netherlands

5. Lars Elzinga

   Bravis Ziekenhuis

   Affiliation as printed

   Bravis Hospital, Roosendaal, Netherlands

6. Ismaïl Gültuna

   Albert Schweitzer Ziekenhuis

   Affiliation as printed

   Albert Schweitzer Hospital, Zwijndrecht, Netherlands

7. Emre Almac Aachen

   Alrijne Ziekenhuis

   Affiliation as printed

   Alrijne Hospital, Leiderdorp, Netherlands

8. Ganesan Baranidharan

   Leeds Teaching Hospitals NHS Trust

   Affiliation as printed

   Leeds Teaching Hospital, Leeds, UK

9. Serge Nikolic

   St Bartholomew's Hospital

   Affiliation as printed

   St. Bartholomew's Hospital, London, UK

10. Ashish Gulve

    James Cook University Hospital

    Affiliation as printed

    James Cook University Hospital, Middlesbrough, UK

11. Jan Vesper

    Heinrich Heine University Düsseldorf

    Affiliation as printed

    Heinrich-Heine University Düsseldorf, Düsseldorf, Germany

12. Birte E. Dietz

    Saluda Medical Europe Limited (United Kingdom)

    Affiliation as printed

    Saluda Medical Europe Ltd, Harrogate, UK

13. Dave Mugan

    Saluda Medical Europe Limited (United Kingdom)

    Affiliation as printed

    Saluda Medical Europe Ltd, Harrogate, UK

14. Frank J.P.M. Huygen

    Amsterdam UMC Location University of Amsterdam

    Affiliation as printed

    Academisch Universitair Medisch Centrum, Amsterdam, Netherlands