1. Pain Physician 2020;23;451-460Comparison of Spinal Cord Stimulation Waveforms for Treating Chronic Low Back Pain: Systematic Review and Meta-Analysis
   Systematic Review
   Tuan Tang, MD, Alaa Abd-Elsayed, MD, Timothy Deer, MD, Sayed Wahezi, MD, Jay Karri, MD, and Vwaire Orhurhu, MD.

BACKGROUND: The treatment of chronic refractory low back pain (LBP) is challenging. Conservative and pharmacologic options have demonstrated limited efficacy. Spinal cord stimulation (SCS) has been shown to be effective in reducing chronic LBP in various contexts. With emerging SCS technologies, the collective evidence of novel waveforms relative to traditional tonic stimulation for treating chronic LBP has yet to be clearly characterized.

OBJECTIVES: To provide evidence for various SCS waveforms—tonic, burst, and high frequency (HF)—relative to each other for treating chronic LBP.

STUDY DESIGN: Systematic review and meta-analysis.

METHODS: PubMed, Medline, Cochrane Library, prior systematic reviews, and reference lists were screened by 2 separate authors for all randomized trials and prospective cohort studies comparing different SCS waveforms for treatment of chronic LBP.

RESULTS: We identified 11 studies that included waveform comparisons for treating chronic LBP. Of these, 6 studies compared burst versus tonic, 2 studies compared burst versus HF, and 3 studies compared tonic versus HF. A meta-analysis of 5 studies comparing burst versus tonic was conducted and revealed pooled superiority of burst over tonic in pain reduction. One study comparing burst versus tonic was excluded given technical challenges in data extraction.

LIMITATIONS: Both randomized controlled trials and prospective cohort studies were included for meta-analysis. Several studies included a high risk of bias in at least one domain.

CONCLUSIONS: Burst stimulation is superior to tonic stimulation for treating chronic LBP. However, superiority among other waveforms has yet to be clearly established given some heterogeneity and limitations in evidence. Given the relative novelty of burst and HF SCS waveforms, evidence of longitudinal efficacy is needed.

KEY WORDS: Chronic low back pain, spinal cord stimulation, tonic, burst, high frequency