Abstract
Background The SUNBURST Study, a USA-based controlled cross-over trial demonstrated that burst spinal cord stimulation was superior compared to tonic stimulation in suppressing chronic intractable pain. However, when on burst stimulation, participants preferred lower to higher amplitudes. This led to the hypothesis that lower burst amplitudes will correlate with lower pain scores while higher amplitudes will be associated with higher pain scores. Objective To investigate correlations between burst amplitude and self-reported pain and different psychosocial measures. Materials and Methods One hundred participants in the SUNBURST study were randomized to receive burst or tonic stimulation, each for 12 weeks in a cross-over manner. Complete data of 99 participants were used in this secondary analysis. Pearson correlations were conducted at 6-, 12-, 18-, and 24-weeks postactivation to determine the strength of linear relationships between burst amplitude and (1) the average seven-day daily pain Visual Analogue Scale (VAS), (2) the different domains of the Pain Catastrophizing Scale (PCS), (3) the different domains of the SF-36v2 (Quality Metric Incorporated, Lincoln, RI) Health Survey. In addition, correlations between tonic stimulation amplitude and the above-mentioned outcome measures were examined. Results Significant positive correlations were identified between burst amplitude and total, "worst," and "trunk" pain for VAS; all domains for PCS; and "Role-Physical," "Bodily Pain," and "General Health" for SF-36v2 (TM) after 12-weeks of burst stimulation. Conclusions In burst spinal cord stimulation, in contrast to tonic stimulation, lower amplitudes are more effective in suppressing pain than high amplitudes.