Novel Spinal Cord Stimulation Waveforms for Treating Back and Leg Pain: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Abstract

Background: Spinal cord stimulation (SCS) has been suggested as a treatment option to improve the quality-adjusted life years of individuals with low back pain. However, previous reviews have some methodologic limitations. This review aims to evaluate the effectiveness of novel SCS waveforms on pain outcomes in patients with low back pain (LBP) compared with traditional SCS or placebo comparator.

Materials and methods: Nine electronic data bases, ongoing trials, gray literature, and targeted journals were searched from inception to December 27, 2021. The Cochrane risk of bias and Grading of Recommendation, Assessment, Development, and Evaluations were used to appraise individual and overall evidence. Subjects aged ≥ 18 years with or without previous surgeries and having LBP for at least three months were included. The primary outcome was pain intensity including back or leg pain scores at postintervention. Secondary outcomes comprised decrease in back, leg, and overall pain, and health-related quality of life.

Results: A total of 11 randomized controlled trials (RCTs) involving 955 participants across four countries were included. Our meta-analysis revealed that novel SCS waveform was superior to traditional SCS or placebo comparator for treating leg pain (Z = -2.12, p = 0.03) with a small effect size (Hedges' g = -0.18, 95% CI: -0.34 to -0.01). Back-pain intensity (g = -0.22, 95% CI: -0.47 to 0.02) and health-related quality of life (g = -0.12, 95% CI: -0.43 to 0.18) were similar between the novel SCS waveform group and the traditional SCS or placebo comparator groups. The meta-regression did not identify any effect of the covariates on back-pain intensity.

Conclusions: With low certainty of evidence, this finding provides a rationale for considering the novel SCS waveform as complements to the usual therapeutic plan. Future trials should adopt well-designed RCTs with larger sample size and follow-up assessment.

Keywords: Low back pain; meta-analysis; spinal cord stimulation; systematic review.