BACKGROUND: Chronic back pain is a debilitating condition that significantly diminishes a patient's quality of life and imposes a substantial economic burden, driven by ongoing health care costs and lost workdays.
OBJECTIVES: This trial aimed to assess the efficacy and safety of an externally powered neuromodulation system targeting the proximal peripheral nerves at the T9 dermatome for chronic back pain refractory to surgery or standard treatment by comparing sub-threshold active stimulation therapy to sham.
STUDY DESIGN: This is a prospective, multicenter, double-blinded, randomized controlled trial. Adhering to the highest standards of methodological quality control, the 38 patients who completed the study had been randomized in a 1:1 ratio to receive either subthreshold active stimulation or sham stimulation using the same Freedom® (Curonix LLC) Peripheral Nerve Stimulator System.
SETTING: This is a randomized controlled trial conducted at 2 independent clinical sites representing distinct secondary and tertiary clinical settings.
METHODS: Both the patients and the assessors were fully blinded. All patients were implanted with 2 4-electrode neurostimulators over the proximal peripheral nerves at the T9 level, in a single-stage direct to permanent procedure. The primary endpoint assessed the difference (at least 50% overall relief or a return to 30 mm or less on the Visual Analog Scale) between subthreshold stimulation and sham stimulation. Patients who received the sham treatment were unblinded and were then given the active treatment throughout the different visits if they reported a lack of response. A per-protocol analysis was conducted at the one-month visit. Patients were followed for 36 months.
RESULTS: Thirty-eight (active: n = 19; sham: n = 19) patients completed the one-month primary endpoint. Superiority for the primary endpoint was confirmed for the active stimulation arm with a responder rate of 63% compared to the sham arm with only a 16% responder rate (P = 0.007). In addition, the active stimulation patients programmed with subthreshold frequencies experienced statistically and clinically significant improvements in Visual Analog Scale scores, the Oswestry Disability Index. the European Quality of Life Survey, the EuroQOL-5 Dimension Questionnaire, and the Patient Global Impression of Change compared to the sham group. Pain relief, improved functionality, and patient satisfaction were consistently reported throughout the study and were sustained through the 36-month follow-up.
LIMITATIONS: While the study was rigorously designed and executed, residual confounding cannot be entirely excluded.
CONCLUSION: This trial showed statistically or clinically significant reductions in low back pain in patients with both Persistent Spinal Pain Syndrome Type 1 (chronic back pain without prior spine surgery) and Persistent Spinal Pain Syndrome Type 2 (chronic pain post spinal surgery), using neurostimulators applied to the proximal peripheral nerves at T9 using subthreshold high-frequency stimulation.
| Discipline Area | Score |
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| Physician |  |
Physician rater
This prospective, multicenter, double-blind RCT of High-Frequency Stimulation for the treatment of chronic low back pain is less invasive than conventional Spinal Cord Stimulation (SCS), and also less likely to be interference-prone due to its sub-threshold stimulation approach. A direct comparison between the two modalities would be of considerable interest.
, McMaster University