Durability of the Therapeutic Effect of Restorative Neurostimulation for Refractory Chronic Low Back Pain

Abstract

Objectives The purpose of the ongoing follow‐up of ReActiv8‐A clinical trial is to document the longitudinal benefits of episodic stimulation of the dorsal ramus medial branch and consequent contraction of the lumbar multifidus in patients with refractory mechanical chronic low back pain (CLBP). We report the four‐year outcomes of this trial. Materials and Methods ReActiv8‐A is a prospective, single‐arm trial performed at nine sites in the United Kingdom, Belgium, and Australia. Eligible patients had disabling CLBP (low back pain Numeric Rating Scale [NRS] ≥6; Oswestry Disability Index [ODI] ≥25), no indications for spine surgery or spinal cord stimulation, and failed conventional management including at least physical therapy and medications for low back pain. Fourteen days postimplantation, stimulation parameters were programmed to elicit strong, smooth contractions of the multifidus, and participants were given instructions to activate the device for 30‐min stimulation‐sessions twice daily. Annual follow‐up through four years included collection of NRS, ODI, and European Quality of Life Score on Five Dimensions (EQ‐5D). Background on mechanisms, trial design, and one‐year outcomes were previously described. Results At baseline (N = 53) (mean ± SD) age was 44 ± 10 years; duration of back pain was 14 ± 11 years, NRS was 6.8 ± 0.8, ODI 44.9 ± 10.1, and EQ‐5D 0.434 ± 0.185. Mean improvements from baseline were statistically significant (p < 0.001) and clinically meaningful for all follow‐ups. Patients completing year 4 follow‐up, reported mean (±standard error of the mean) NRS: 3.2 ± 0.4, ODI: 23.0 ± 3.2, and EQ‐5D: 0.721 ± 0.035. Moreover, 73% of participants had a clinically meaningful improvement of ≥2 points on NRS, 76% of ≥10 points on ODI, and 62.5% had a clinically meaningful improvement in both NRS and ODI and 97% were (very) satisfied with treatment. Conclusions In participants with disabling intractable CLBP who receive long‐term restorative neurostimulation, treatment satisfaction remains high and improvements in pain, disability, and quality‐of‐life are clinically meaningful and durable through four years.

Non-Spinal Neuromodulation of the Lumbar Medial Branch Nerve for Chronic Axial Low Back Pain: A Narrative Review

“…Percutaneous PNS of the LMBN is a relatively new modality, and to date, there are 10 human, clinical studies focusing on nonspinal neuromodulation for chronic axial LBP (16)(17)(18)(19)(20)(21)(22)(23)(24)(25). Kapural et al (25) was the first to publish clinical data using the SPRINT device.…”

“…An important critique is that the data analysis did not include patients who explanted due to inefficacy of the therapy, so the true responder rates may be over-stated. Lastly, Mitchell et al ( 18 ) studied 53 patients in a prospective, multicenter, single arm trial that extended to4 years. Again, all outcome (NRS, ODI, EQ-5D) measures were significantly increased from baseline at the 4-year mark ( p < 0.05).…”

“…Again, all outcome (NRS, ODI, EQ-5D) measures were significantly increased from baseline at the 4-year mark ( p < 0.05). Moreover, Mitchell found that 62.5% of participants had clinically meaningful improvement in both NRS and ODI ( 18 ). In this study, though the sample size was modest, the long-term follow up is notable as it is the only study in this review with this follow up length.…”

The Added Value of Subcutaneous Peripheral Nerve Field Stimulation Combined with SCS, as Salvage Therapy, for Refractory Low Back Pain Component in Persistent Spinal Pain Syndrome Implanted Patients: A Randomized Controlled Study (CUMPNS Study) Based on 3D-Mapping Composite Pain Assessment

“…We would carefully hypothesize that PNfS, as peripheral nerve stimulation, implanted in front of paravertebral muscles, innervated fascia and aponeurosis, could have an electrical influence on proximal structures, and could play an indirect role as a spinal musculoskeletal system electronic booster, helping to regain function by improving muscular adaptation and to increase proprioceptive feedback coming from this complex musculature. This concept has been the subject of new developments in peripheral nerve stimulation, as published by Eldabe's team [37,38], and could be transposed to the differential role and added-value of PNfS to SCS.…”

The Added Value of Subcutaneous Peripheral Nerve Field Stimulation Combined with SCS, as Salvage Therapy, for Refractory Low Back Pain Component in Persistent Spinal Pain Syndrome Implanted Patients: A Randomized Controlled Study (CUMPNS Study) Based on 3D-Mapping Composite Pain Assessment

“…We would carefully hypothesize that PNfS, as peripheral nerve stimulation, implanted in front of paravertebral muscles, innervated fascia and aponeurosis, could have an electrical influence on proximal structures, and could play an indirect role as a spinal musculoskeletal system electronic booster, helping to regain function by improving muscular adaptation and to increase proprioceptive feedback coming from this complex musculature. This concept has been the subject of new developments in peripheral nerve stimulation, as published by Eldabe's team [34,35], and could be transposed to the differential role and added-value of PNfS to SCS.…”