Neurophysiological Sensitivity to Spinal Cord Stimulation

This pilot study investigates the effects of reducing pain medication including opioids and anticonvulsants, on spinal cord sensitivity during closed-loop spinal cord stimulation (SCS). Patients with Persistent Spinal Pain Syndrome Type 2 (FBSS/FNSS) will undergo a standard 21-day SCS trial with the Evoke closed-loop system, followed by permanent implantation if successful. Neurophysiological responses (activation plots, conduction velocity, chronaxie, rheobase) and patient-reported outcomes (VAS, activity, sleep, medication intake) will be collected during the trial and up to 6 months after implantation. The goal is to evaluate the relationship between medication tapering and spinal cord sensitivity

This study is being conducted in patients who will receive a spinal cord stimulator. This device helps manage chronic neuropathic pain in the trunk and/or limbs. The patients will receive a spinal cord stimulator that is available, notified, and reimbursed in Belgium, which uses a special technology automatically adjusting the intensity of the stimulation. This is called a closed-loop system. The closed-loop system stimulates the Beta fibers in the spinal cord and simultaneously measures their response. Based on the measured response, the stimulation strength is automatically adjusted. In Belgium, after implant of the leads the effect must first be evalauted for 3 weeks before implanting the Internal Pulse Generator; this is called the trial period. Only if the trial is successful, the patients will receive a permanent implant. The primary goal of the study is to evaluate how different types of pain medication influence the neurophysiological response of the Beta fibers during spinal cord stimulation. Patients will be divided into three groups, based on the medication they are taking before receiving a spinal cord stimulator: * patients not taking any pain medication, * patients taking strong opioids, * patients taking anticonvulsant medication. As part of the study, patients will follow the normal clinical schedule. During visits, they will be asked questions about their pain, sleep, medication use, and activity. The study will end one month after the patient receives the permanent spinal cord stimulator implant.