Pain Sketches to Predict Pain following Primary Targeted Muscle Reinnervation in Amputees

Background:Numeric scales are validated methods to report pain outcomes after targeted muscle reinnervation (TMR) but do not include the assessment of qualitative pain components. This study evaluates the application of pain sketches within a cohort of patients undergoing primary TMR and describes differences in pain progression according to early postoperative sketches.Methods:This study included 30 patients with major limb amputation and primary TMR. Patients' drawings were categorized into four categories of pain distribution [focal pain (FP), radiating pain (RP), diffuse pain (DP), or no pain (NP)] and interrater reliability was calculated. Second, pain outcomes were analyzed for each category. Pain scores were the primary outcome, and Patient-Reported Outcomes Measurement Information System (PROMIS) instruments were the secondary outcome.Results:The interrater reliability for the sketch categories was good (overall kappa coefficient of 0.8). The NP category reported a mean decrease in pain of 4.8 points, followed by the DP (2.5 points) and FP categories (2.0 points). The RP category reported a mean increase in pain of 0.5 points. For PROMIS Pain Interference and Pain Intensity, the DP category reported a mean decrease of 7.2 and 6.5 points, respectively, followed by the FP category (5.3 and 3.6 points). The RP category reported a mean increase of 2.0 points in PROMIS Pain Interference and a mean decrease of 1.4 points in PROMIS Pain Intensity. Secondary outcomes for the NP category were not reported.Conclusion:Pain sketches demonstrated reliability in pain morphology assessment and might be an adjunctive tool for pain interpretation in this setting.