A Randomized Controlled Trial of Subcutaneous Nerve Stimulation for Back Pain Due to Failed Back Surgery Syndrome: The SubQStim Study

Objectives To compare the effectiveness of peripheral nerve stimulation utilizing a subcutaneous lead implant technique-subcutaneous nerve stimulation (SQS) plus optimized medical management (SQS + OMM arm) vs. optimized medical management alone (OMM arm) in patients with back pain due to failed back surgery syndrome. Patients and Methods Patients were recruited from 21 centers, in Europe, Israel, and Australia. Eligible patients were randomized (1:1) to SQS + OMM or OMM arms. Those in the SQS arm were implanted with a neurostimulator and up to two subcutaneous percutaneous cylindrical leads in the area of pain. Patients were evaluated pre-randomization and at one, three, six, and nine months post-randomization. The primary endpoint was the proportion of subjects with a >= 50% reduction in back pain intensity (responder) from baseline to nine months. Secondary outcomes included proportion of responders with a >= 50% reduction in back pain intensity at six months and >= 30% reduction at nine months, and the mean change from baseline in back pain intensity at six and nine months between the two arms. Results Due to the slow rate of recruitment, the study was terminated early with 116 subjects randomized. A total of 33.9% (19/56, missing: n = 20 [36%]) of subjects in the SQS + OMM arm and 1.7% (1/60, missing: n = 24 [40%]) in the OMM arm were responders at Month 9 (p < 0.0001). Secondary objectives showed a significant difference in favor of SQS + OMM arm. Conclusion The results indicate that the addition of SQS to OMM is more effective than OMM alone in relieving low back pain at up to nine months.