Burst Spinal Cord Stimulation: A Systematic Review and Pooled Analysis of Real-World Evidence and Outcomes Data

Abstract

Objective: This review provides a comprehensive assessment of the effectiveness of burst spinal cord stimulation (SCS). Ratings of pain intensity (visual analog scale or numeric rating scale) and patient-reported outcomes (PROs) on functional/psychometric domains such as depression (Beck Depression Index), catastrophizing (Pain Catastrophizing Scale), surveillance (Pain Vigilance and Attention Questionnaire), and others are addressed.

Design: Articles were identified and selected from the literature according to prospective, replicable methods. Effectiveness data-pain scores and PRO ratings-were weighted by study sample sizes and pooled. The effects of burst SCS were compared against values at baseline and with tonic SCS. For PROs, published population norms were used for comparison.

Results: Fifteen articles, with a combined sample size of 427, were included. Follow-up ranged from a few hours to two years. A variety of prospective designs were employed, including crossover studies, single-arm cohorts, and a randomized controlled trial, as well as retrospective case reports. The weighted pooled mean pain rating across articles at baseline was 76.7 (±27.4). With tonic SCS, this was reduced to 49.2 (±12.9), and with burst SCS it was further reduced to 36.7 (±11.6), a 12.5-point difference between tonic and burst values. Psychometric analyses of PROs noted preferential improvement with burst SCS. In addition, 65% of subjects stated a preference for burst SCS.

Conclusions: In pooled analyses that incorporated all available published evidence, the improvement over baseline for burst SCS was shown to have a clinically important incremental benefit over tonic SCS. In addition, burst SCS may support resolution of the emotional or cognitive aspects of pain that are mediated by medial thalamo-cortical pathways. This study highlights the value in considering the entire knowledge base in therapeutic assessments as well as adopting a consistent set of outcome variables within neuromodulation. Burst SCS is a valuable intervention, providing both analgesia and psychometric benefits that warrant further thoughtful applications.

Keywords: Affective and Medial Pathway; Burst Stimulation; Chronic Pain; Depression; Neuromodulation; Pooled Analysis; Spinal Cord Stimulation.

Figure 1

Summary of article selection.

Figure 2

Pain scores (visual analog scale or numeric rating scale) at baseline or with active spinal cord stimulation (tonic vs burst) are compared. Left side: Bar heights represent pooled weighted means across studies for each of the stimulation conditions. Error bars represent standard error of the mean. Right side: Points represent means for each of the studies that contributed to the pooled means for each of the stimulation conditions.

Figure 3

Across studies, a higher proportion of subjects preferred burst spinal cord stimulation (SCS) than preferred tonic SCS or another SCS/had no preference. Bar heights represent pooled means across studies for each of the stimulation conditions. Error bars represent standard error of the mean.

Figure 4

Depression (Beck Depression Inventory, top), pain catastrophizing (Pain Catastrophizing Scale, middle), and pain vigilance and awareness (Pain Vigilance and Attention Questionnaire, bottom) scores were highest at baseline and were reduced after treatment with burst spinal cord stimulation. Bar heights represent pooled means across studies. Population norms from the literature are included for comparisons (green bars).

Figure 5

Patient-reported outcome (PRO) scores were normalized as proportions of the maximum/worst possible score for each instrument and weighted by sample size. Combined pooled means were then calculated for all PROs across studies at baseline or with active spinal cord stimulation (SCS; tonic vs burst). Left side: Bar heights represent pooled means across SCS studies at baseline, with tonic SCS, and with burst SCS. Error bars represent standard error of the mean. Pooled population norms from the literature (also normalized and weighted by the same method; green bar) are included as a comparison. Right side: Points represent normalized scores for each of the studies that contributed to the pooled means for each of the stimulation conditions.

Figure 6

Passive-recharge BurstDR waveform (left) and active recharge burst waveform (right), termed “clustered tonic stimulation” by one author. Reprinted with permission from De Ridder [53].