Questionnaire-based approach to evaluate the convenience of rechargeable extracorporeal pulse generators for wireless spinal cord stimulation

Spinal cord stimulation (SCS) has been utilized for more than 50 years to treat refractory neuropathic pain. Currently, SCS systems with fully implantable pulse generators (IPGs) represent the standard. New wireless extracorporeal SCS (wSCS) devices without IPGs promise higher levels of comfort and convenience for patients. However, to date there are no studies on how charging and using this wSCS system affects patients and their therapy. This study is the first questionnaire-based survey on this topic focusing on patient experience. The trial was a single arm, open-label and mono-centric phase IV study. Standardized questionnaires were sent to all patients with a wSCS device in use at the time of trial. The primary endpoint was the convenience of the charging and wearing process scored on an ordinal scale from "very hard" (1) to "very easy" (5). Secondary endpoints included time needed for charging, the duration of stimulation per day and complication rates. Questionnaires of 6 out of 9 patients were returned and eligible for data analysis. The mean age of patients was 61.3 ± 6.7 (± SD) years. The duration of therapy was 20.3 ± 15.9 months (mean ± SD). The mean duration of daily stimulation was 17 ± 5.9 h (mean ± SD). n = 5 patients rated the overall convenience as "easy" (4) and n = 3 patients evaluated the effort of the charging process and wearing of the wSCS device as "low" (4). n = 5 patients considered the wearing and charging process as active participation in their therapy. n = 5 patients would choose an extracorporeal device again over a conventional SCS system. Early or late surgical complications did not occur in this patient collective. Overall, patients felt confident using extracorporeal wSCS devices without any complications. Effort to maintain therapy with this system was rated as low.