Soleymani, Hunter

Importance Chronic pain is a leading cause of disability, and many affected patients rely on long-term opioid therapy despite its unfavorable adverse effect profile. Spinal cord stimulation is an established therapy for chronic pain that may secondarily reduce opioid consumption by providing sustained analgesia. Objective To quantify changes in opioid use following spinal cord stimulation implantation for the treatment of chronic pain through a systematic review and meta-analysis. Data sources We conducted a comprehensive search of MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Scopus from each database’s inception to July 1, 2024. Study selection We included studies describing patients who underwent spinal cord stimulator implantation for the treatment of chronic pain. A total of 2,784 potential studies were identified and screened by multiple independent reviewers, yielding a final total of 43 studies included in the systematic review. Data extraction and synthesis Data extraction was completed by multiple independent reviewers following Preferred Reporting Items for Systematic Reviews and Meta-Analysis and Meta-analysis Of Observational Studies in Epidemiology guidelines. A random effects model with Hartung-Knapp-Sidik-Jonkman adjustment was used to estimate pooled estimates. Certainty assessment was performed following the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) framework. Main outcome(s) and measure(s) The primary outcomes were change in continuous opioid use (ie, morphine milligram equivalent (MME)) and categorical opioid use (yes/no) from preimplantation to 12 months following spinal cord stimulator implantation. Results Meta-analysis of 12 month continuous MME use comprising 22 study comparisons (1,666 individuals) revealed a weighted mean difference of −18.06 MME (95% CI −24.41 to −11.70; 95% prediction interval −38.29 to 2.17; p<0.001). Meta-analysis of categorical opioid use at 12 months comprising 24 study comparisons (1,527 individuals) revealed an OR of 0.47 (95% CI 0.30 to 0.75; 95% prediction interval 0.10 to 2.11; p=0.003), signifying lower odds of opioid continuation. Conclusions and relevance Spinal cord stimulation is associated with reduced opioid dose consumption and increased odds of opioid cessation at 12 months postimplantation compared with baseline in patients with chronic pain; however, both of these conclusions are supported by evidence of very low GRADE certainty. PROSPERO registration number CRD42024574921.

Background Peripheral nerve stimulation (PNS) has emerged as a promising neurostimulation modality, yet its effectiveness and durability for chronic pain remain uncertain. We conducted a systematic review and meta-analysis to evaluate changes in pain intensity following implantable PNS therapy. Methods Eligible studies included adults (≥18 years) with chronic pain treated with an implantable PNS system, and pain intensity was assessed at baseline and follow-up time points. The primary outcome was change in pain intensity from baseline to 6 months after PNS implantation. Secondary outcomes included changes in pain intensity at 3, 12 and 24 months after PNS implantation. Standardized mean differences (Hedges’ g ) were pooled using a random-effects model. Results A total of 106 studies comprising 9272 patients were included. PNS was associated with large, statistically significant reductions in pain intensity from baseline to all time points: 3 months (Hedges’ g 2.92; 95% CI 2.62 to 3.21), 6 months (Hedges’ g 3.08; 95% CI 2.68 to 3.48), 12 months (Hedges’ g 2.68; 95% CI 2.30 to 3.05) and 24 months (Hedges’ g 2.08; 95% CI 1.68 to 2.48) (all p<0.001). However, the certainty of evidence as assessed by the Grading of Recommendations Assessment, Development and Evaluation criteria was rated as low for the primary outcome, due to pooling from observational studies, risk of bias, and heterogeneity (statistical, clinical and methodological). Subgroup analyses revealed no differences by study design or device type, while smaller effect sizes were reported in industry-funded studies and those with declared conflicts of interest. The largest effect sizes were observed in pelvic and upper extremity pain, whereas the smallest in truncal pain. Conclusion Implantable PNS provides persistent and clinically meaningful analgesia for chronic pain, with benefits sustained up to 24 months. These findings support broader clinical adoption and provide evidence to inform pay0r coverage and policy decisions.