Disclosures: Alexios G. Carayannopoulos, DO, MPH, DABPMR, FFSMB, FAAOE: No financial relationships or conflicts of interest

Objective: To determine long-term durability of clinical benefits of an implantable Restorative Neurostimulation system (ReActiv8® by Mainstay Medical; PMA Granted by FDA in 2020) in patients with refractory chronic low back pain (CLBP) and multifidus muscle dysfunction. Restorative neurostimulation overrides underlying multifidus muscle inhibition by stimulation of the L2 medial branch of the dorsal ramus nerve with the aim of restoring functional spine stability and consequently reducing mechanically induced pain.

Design: Prospective, open label, two-year follow-up of trial participants.Setting : Twenty-six multidisciplinary centers in the United States, Australia, and Europe.Participants : Refractory CLBP and evidence of multifidus dysfunction (prone-instability-test). Pain-intensity ≥6 cm on a 10-cm Visual-Analog-Scale (LBP-VAS) and disability ≥21 points on the Oswestry Disability Index (ODI). No indication for spine surgery.

Interventions: All participants received the implanted Restorative Neurostimulation system, self-administered up to 60 minutes of stimulation per day, and were followed-up through two years.

Main Outcome Measures: LBP-VAS; ODI; EQ-5D; opioid use; related adverse events.

Results: At baseline (N&#3f204), participants were 47±9 years of age, had back pain for 14±11 years, average LBP-VAS of 7.3±0.7 cm, ODI of 39.1±10.3 points, EQ-5D of 0.585±0.174 and LBP on 97±8% of days during the year before enrollment. At two years (N&#3f159), average LBP-VAS had improved by -4.8±2.4 cm (-65.9±32.6%) (P < 0.0001), ODI by -21.7±16.8 points (-54.7±39.2%) (P < 0.0001) and EQ-5D by 0.215±0.215 (P < 0.0001); 71% of participants had ≥50% LBP-VAS reduction; 66% had VAS≤2.5cm (LBP-resolution); 62% had ≥20 points ODI reduction; 77% had ≥50% reduction in LBP-VAS and/or ODI; and 59% voluntarily eliminated or reduced opioid consumption. The overall safety profile is favorable, and no lead migrations were observed.Conclusions: Restorative neurostimulation is an effective, safe, and durable treatment for patients with refractory CLBP, multifidus muscle dysfunction and no indications for spine surgery. Ongoing accrual and durability of clinical benefits in function, symptoms, and quality of life is consistent with restoration of neuromuscular control.

Level of Evidence: Level I

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/long-term-durability-of-clinical-benefits-of-restorative-neurostimulation-in-patients-with-chronic-low-back-pain-and-multifidus-muscle-dysfunction-two-year-pivotal-trial-results/