Placebo Effect In Spinal Cord Electrical Stimulation for Pain

Objective: To evaluate if spinal cord stimulation (SCS) performs better than placebo (no stimulation) in the long term to reduce persistent neuropathic leg pain refractory to medication and other conservative treatments in patients who have undergone lumbar spinal surgery. Study design: Multicenter, double blind, randomized, sham-controlled trial. After a positive SCS test trial, participants (18-70 years) will be implanted with a non-rechargeable SCS system providing active, subthreshold stimulation and followed for 12 months in a blinded cross-over design. The primary outcome measure is the difference in change in leg pain intensity scores using the Numeric Rating Scale (NRS) between a 3-month period with optimized subthreshold stimulation, and a 3-month period with no stimulation, as compared to baseline. Quality of life, physical functioning, sleep quality, return to work, and reduction in medication use will also be investigated. Background: Up to 20% of patients who have undergone lumbar spinal surgery experience persistent back/leg pain leading to long-term reduction in functionality and quality of life. SCS is an established and safe, minimally invasive treatment for these patients when no further surgery is indicated and conservative therapies have been found to be ineffective. Placebo-controlled studies, comparing active and sham stimulation, were lacking until recently as traditional SCS relied on the patient feeling the stimulation (paresthesia). Technological progress with development of paresthesia-free stimulation forms now allows for the execution of placebo-controlled studies. A recent trial showing no significant difference in long-term effectiveness between active SCS and sham suffers from significant methodological shortcomings. This necessitates further sham-controlled studies to determine the effectiveness of SCS.