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 is a single-centre, open-label, prospective pilot study in Belgium. Twenty patients scheduled for SCS with the Evoke ECAP-controlled closed-loop system will be enrolled. Eligible patients must use at least one qualifying pain medication at a minimum daily dose (gabapentin ≥150 mg, pregabalin ≥75 mg, morphine ≥40 mg, hydromorphone ≥10 mg, oxycodone ≥20 mg, fentanyl ≥25 µg).

The study includes baseline assessments, a 3-week trial period, permanent implantation if successful, and follow-up visits at 1, 3, and 6 months. Data collected include VAS pain, sleep, activity, medication use, and neurophysiological parameters (activation plots, conduction velocity, chronaxie, rheobase).

The primary endpoint is the effect of medication reduction on spinal cord sensitivity to SCS. Secondary endpoints include changes in pain intensity, medication use, sleep, activity, and additional neurophysiological outcomes.

Inclusion Criteria:

• Candidate for SCS and scheduled for trial with Evoke system.
• Diagnosis of FBSS or FNSS (PSPS-T2).
• Current use of ≥1 qualifying pain medication at or above minimum daily dose:
• Gabapentin ≥150 mg
• Pregabalin ≥75 mg
• Morphine ≥40 mg
• Hydromorphone ≥10 mg
• Oxycodone ≥20 mg
• Fentanyl ≥25 µg
• Signed informed consent.
• Age ≥18 years.

Exclusion Criteria:

• Active disruptive psychiatric disorder or condition impacting pain perception or compliance.
• Progressive neurological disease (MS, CIDP, progressive arachnoiditis, progressive diabetic neuropathy, brain/spinal tumor, severe spinal stenosis).
• Coagulation disorder, platelet dysfunction, progressive vascular disease, or uncontrolled diabetes with procedural risk.
• Active systemic or local infection.
• Pregnancy.
• Significant untreated addiction or substance abuse (within 6 months prior)

Belgian patients selected for spinal cord stimulation (SCS) with Failed Back Surgery Syndrome ( FBSS )

The international committee of medical journal editors believes there is an ethical obligtion to share data generated by interventional clinical trials. This is not considered an interventional clinical trial