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Background: Impaired neuromuscular control and degeneration of the multifidus muscle have been linked to the development of refractory chronic low back pain (CLBP). An implantable restorative-neurostimulator system can override the underlying multifidus inhibition by eliciting episodic, isolated contractions. The ReActiv8-B randomized, active-sham-controlled trial provided effectiveness and safety evidence for this system, and all participants received therapeutic stimulation from four months onward. Objective: This study aimed to evaluate the two-year effectiveness of this restorative neurostimulator in patients with disabling CLBP secondary to multifidus muscle dysfunction and no indications for spine surgery. Materials and Methods: Open-label follow-up of 204 participants implanted with a restorative neurostimulation system (ReActiv8, Mainstay Medical, Dublin, Ireland) was performed. Pain intensity (visual analog scale [VAS]), disability (Oswestry disability index [ODI]), quality-of-life (EQ-5D-5L), and opioid intake were assessed at baseline, six months, one year, and two years after activation. Results: At two years (n = 156), the proportion of participants with ≥50% CLBP relief was 71%, and 65% reported CLBP resolution (VAS ≤ 2.5 cm); 61% had a reduction in ODI of ≥20 points, 76% had improvements of ≥50% in VAS and/or ≥20 points in ODI, and 56% had these substantial improvements in both VAS and ODI. A total of 87% of participants had continued device use during the second year for a median of 43% of the maximum duration, and 60% (34 of 57) had voluntarily discontinued (39%) or reduced (21%) opioid intake. Conclusions: At two years, 76% of participants experienced substantial, clinically meaningful improvements in pain, disability, or both. These results provide evidence of long-term effectiveness and durability of restorative neurostimulation in patients with disabling CLBP, secondary to multifidus muscle dysfunction. Clinical Trial Registration: The study is registered on clinicaltrials.gov with identifier NCT02577354.

Chronic low back pain can be caused by impaired control and degeneration of the multifidus muscles and consequent functional instability of the lumbar spine. Available treatment options have limited effectiveness and prognosis is unfavorable. We conducted an international randomized, double-blind, sham-controlled trial at 26 multidisciplinary centers to determine safety and efficacy of an implantable, restorative neurostimulator designed to restore multifidus neuromuscular control and facilitate relief of symptoms (clinicaltrials.gov identifier: NCT02577354). Two hundred four eligible participants with refractory mechanical (musculoskeletal) chronic LBP and a positive prone instability test indicating impaired multifidus control were implanted and randomized to therapeutic (N = 102) or low-level sham (N = 102) stimulation of the medial branch of the dorsal ramus nerve (multifidus nerve supply) for 30 minutes twice daily. The primary endpoint was the comparison of responder proportions (≥30% relief on the LBP visual analogue scale without analgesics increase) at 120 days. After the primary endpoint assessment, participants in the sham-control group switched to therapeutic stimulation and the combined cohort was assessed through 1 year for long-term outcomes and adverse events. The primary endpoint was inconclusive in terms of treatment superiority (57.1% vs 46.6%; difference: 10.4%; 95% confidence interval, -3.3% to 24.1%, P = 0.138). Prespecified secondary outcomes and analyses were consistent with a modest but clinically meaningful treatment benefit at 120 days. Improvements from baseline, which continued to accrue in all outcome measures after conclusion of the double-blind phase, were clinically important at 1 year. The incidence of serious procedure- or device-related adverse events (3.9%) compared favorably with other neuromodulation therapies for chronic pain.

Background: Restorative neurostimulation is a rehabilitative treatment for patients with refractory chronic low back pain (CLBP) associated with dysfunction of the lumbar multifidus muscle resulting in impaired neuromuscular control. The ReActiv8-B randomized, sham-controlled trial provided evidence of the effectiveness and safety of an implanted, restorative neurostimulator. The two-year analysis previously published in this journal demonstrated accrual of clinical benefits and long-term durability. Objective: Evaluation of three-year effectiveness and safety in patients with refractory, disabling CLBP secondary to multifidus muscle dysfunction and no indications for spine surgery. Materials and Methods: Prospective, observational follow-up of the 204 implanted trial participants. Low back pain visual analog scale (VAS), Oswestry Disability Index (ODI), EuroQol quality of life survey, and opioid intake were assessed at baseline, six months, and one, two, and three years after activation. The mixed-effects model repeated measures approach was used to provide implicit imputations of missing data for continuous outcomes and multiple imputation for proportion estimates. Results: Data were collected from 133 participants, and 16 patients missed their three-year follow-up because of coronavirus disease restrictions but remain available for future follow-up. A total of 62% of participants had a ≥ 70% VAS reduction, and 67% reported CLBP resolution (VAS ≤ 2.5cm); 63% had a reduction in ODI of ≥ 20 points; 83% had improvements of ≥ 50% in VAS and/or ≥ 20 points in ODI, and 56% had these substantial improvements in both VAS and ODI. A total of 71% (36/51) participants on opioids at baseline had voluntarily discontinued (49%) or reduced (22%) opioid intake. The attenuation of effectiveness in the imputed (N = 204) analyses was relatively small and did not affect the statistical significance and clinical relevance of these results. The safety profile remains favorable, and no lead migrations have been observed to date. Conclusion: At three years, 83% of participants experienced clinically substantial improvements in pain, disability, or both. The results confirm the long-term effectiveness, durability, and safety of restorative neurostimulation in patients with disabling CLBP associated with multifidus muscle dysfunction. Clinical Trial Registration: The Clinicaltrials.gov registration number for the study is NCT02577354.

Burst spinal cord stimulation (SCS) can achieve excellent clinical reduction of pain, alongside improvements in function, quality of life, and related outcomes. Good outcomes likely depend on good lead placement, thereby enabling recruitment of the relevant neural targets. Several competing approaches exist for lead implantation, such as the use of single vs bilateral leads and leads lateralized vs placed at midline. The objective of this study was to examine the relationship between paresthesia locations and pain relief with burst SCS in a prospective double-blind crossover design.All participants had bilateral back and leg pain, with more intense pain experienced on one side of the body. A trial SCS system was placed, during which brief intraoperative mapping with conventional stimulation was used to characterize paresthesia locations. Two programs for subperception burst SCS treatment were then applied for two days each, in random order: bilateral paresthesia coverage vs unilateral paresthesia coverage contralateral to the side of the body with more intense pain. Pain ratings (visual analog scale [VAS]) and pain reductions (scaling pain relief [SPR]) were reported for each.Of the 30 participants who completed the study, 24 (80%) had good pain relief with at least one program. A baseline VAS score of 8.75 was reduced to 5.98 with contralateral stimulation and to 2.88 with bilateral stimulation; with SPR, this equated to 31.25% and 67.50% improvement, respectively. The incremental benefit of bilateral stimulation over contralateral stimulation was statistically significant (p 0.001). Of the 24 participants, 87.5% preferred bilateral stimulation, whereas 12.5% preferred unilateral stimulation. The six participants who failed the trial had no preference.When burst stimulation is delivered to spinal targets that can generate paresthesias contralateral to the side of worst pain, suboptimal therapy is achieved. Thus, attention to laterality and pain coverage is critical for successful therapy, and it may be important to carefully consider lead implantation techniques.

Objective: Postherniorrhaphy pain is a not uncommon, and difficult to treat, pain condition. Success with different methods of neurostimulation has been reported in the literature in the last decade. We assess the use of a new modality of neuromodulation—spinal-peripheral neurostimulation (SPN). Materials and Methods: We report the results of treatment of a patient with bilateral, intractable postherniorrhaphy pain with SPN. Results: Significant reduction in pain and decrease in opioid consumption have been achieved. Conclusion: SPN can be an effective treatment for postherniorrhaphy pain resistant to conservative management.

Objective: The goal of the study was to assess the efficacy of interaction between spinal cord stimulation (SCS) and peripheral nerve field stimulation (PNFS) and to evaluate a new spinal-peripheral neuromodulation method for low back pain. Materials and Methods: The prospective two-part study included patients with low back pain due to failed back surgery syndrome and/or spinal stenosis. In the first part 20 patients were implanted with SCS and PNFS. They selected the best program out of three: SCS alone, PNFS alone, or both together. In the second part another 20 patients with the same implanted leads were selecting between three programs: SCS and PNFS separately, SCS as anode and PNFS as cathode, or in reverse. Results: In the first part 79% of the patients selected simultaneous use of SCS and PNFS. The overall success of the trials was 85%. In the second part communication between SCS and PNFS provided wider coverage of axial pain. The overall success of the trials was 90%. Conclusion: Simultaneous use of SCS and PNFS increase efficacy of both methods for axial back pain. The new SPN method showed great potential in providing coverage for back pain.

Introduction. Spinal cord stimulation is a widely used treatment modality for chronic pain, especially failed back surgery syndrome. However, migration of the lead or leads, coverage of axial pain, and the selection of an optimal system configuration continue to be subjects for serious debate. Materials and Methods. A retrospective study of the use of the method of "midline anchoring" of a single Octrode® lead, in 54 patients with low back and/or lower extremity pain, was done to assess the efficacy of this technique. Results. During the study period of 9.3 months, only a 4% revision rate was reported. Reduction in pain of more than 50% and individual patient satisfaction scores were very high (85% and 87%, respectively). Successful bilateral pain coverage was obtained with a single Octrode® lead. The lower extremities and buttocks area were captured in 89% of the patients. Axial pain coverage was achieved in the majority of the patients, with 71% reporting adequate coverage of the upper lumbar spine. A "guarded cathode" array was used in the vast majority of the cases, with a relatively low position of the lead. Conclusions. "Midline anchoring" of the spinal cord stimulation lead is an effective implantation technique, allowing the use of a single, percutaneous, Octrode® lead, while preventing lead migration and allowing capture of axial and lower extremity pain, unilateral as well as bilateral. This study revives the idea of a single lead as a possible optimal configuration.

Intrathecal drug delivery is a widely used and effective method of treatment for chronic intractable pain. Unfortunately all currently used agents can not provide adequate pain relief in all patients. A prospective study of neuroaxial methadone was performed in 24 patients, all of whom had failed treatment with multiple previous intrathecal drugs. Thirteen patients experienced improvement of their pain control with methadone, nine continued to receive this agent for 6 months with good pain relief, improved quality of life and no side effects. The final rates of methadone infusion were 2.2 times higher than preceding morphine rates. The only observed possible side effect of methadone was transient blurred vision in one patient. Methadone is a promising alternative neuroaxial agent in the treatment of chronic pain.

Spinal cord stimulation (SCS) is a popular method of treatment of chronic pain. Unfortunately, migration of the lead continues to be a serious complication of this therapy. In an attempt to reduce lateral migration of the SCS lead, we performed a retrospective assessment of a new technique of percutaneous lead placement. This new method of "midline anchoring" of the lead using the plica mediana dorsalis was tested against conventional technique in a retrospective study involving 122 trials and 91 implants of SCS over a period of five years. The use of "midline anchoring" resulted in a decrease in lead migration from 23% to 6% after trial insertion and from 24% to 7% after implantation. We conclude that "midline anchoring" of the SCS lead is an effective method of preventing lead migration.

Introduction: Patients with extensive surgery in the lumbar and thoracic spine are often not considered for neurostimulation due to the inability to perform a conventional spinal cord stimulation (SCS) trial. We are presenting six such patients in which spinal-peripheral neurostimulation (SPN) was used via a caudal approach. Methods: Six patients with intractable low back and leg pain following extensive lumbar and thoracic surgeries, up to at least the T10 level, underwent a stimulation trial with one caudal lead and one subcutaneous lead in order to achieve SPN. Results: In five cases, the trial was successful with coverage of the pain area and at least satisfactory pain relief. All six patients were implanted with a paddle lead(s) and a subcutaneous lead using SPN with good pain control. Conclusion: SPN with a caudal lead appears to be a viable option for SCS trial in patients with no possibilities for conventional trial lead placement.

Objective: There is a lack of objective measurements of the spinal cord stimulator (SCS) trial results, which leads to increased number of failed permanent placements. Certain modes of sensory functions were tested as possible correlates with trial success. Design. A convenience sample of 44 patients undergoing SCS trial underwent current perception threshold (CPT), pain perception threshold (PPT) and pain tolerance threshold (PTT) testing before and after the procedure. PPT and PTT were also recorded twice at the same period of time in 9 volunteers. Results: PPT, but not PTT, showed an unacceptably high level of intra-individual variability in volunteers. CPT measurements did not produce significant changes after SCS use. PTT not only showed significant changes after SCS trial, but also correlated with the results of the trial and success of the permanent implantation. Conclusion: PTT may possibly serve as an objective measurement of the SCS trial outcome.