Comparison of the visual analog scale (vas) and the scaling pain relief (spr) measurements in the assessment of the results of spinal cord stimulation trial and therapy: A prospective study

Objectives: The goal of this study was to compare the results of evaluating the success of spinal cord stimulation (SCS) using the Visual Analog Scale (VAS) and a Scaling Pain Relief (SPR) measurement. Methods: This prospective study included 29 patients, who were considered good candidates for an SCS trial. In the immediate post trial period, immediate post implant period, and one-month post implant period, pain relief was assessed by VAS percent change and using an SPR measurement (direct patient report of pain relief). Statistical analysis of the results included a repeated measures analysis of variance (ANOVA) comparing VAS percent change versus direct patient report of percentage of pain relief (SPR) at the post trial, post implant, and one month follow-ups for all patients that received a permanent implant. Results: Twenty-one patients had a successful trial and 20 were implanted with a permanent system. There was a strong positive correlation between the two pain relief measures at every measured timepoint. Direct patient reports of percentage of pain relief (SPR) were statistically higher than VAS percent change at the post trial period. Seven patients were considered good candidates for implantation based on the SPR measurement, but not VAS percent reduction. These patients went on to achieve clinically significant changes. Discussion: SPR measurements such as direct patient reports of pain relief should be considered in place of VAS percent change when determining SCS trial success.