Clinical Evaluation of Post-Surgical Scar Hyperesthesia; an Exploratory Longitudinal Study

Evidence for the objective clinical evaluation of scar hyperesthesia is lacking. This exploratory study investigated the clinical relevance and responsiveness of objective scar evaluation measures in adults following hand surgery. With ethical approval and consent, participants were enrolled from one NHS hospital. Patient reported and investigator completed scar morphology, cosmesis, pain and function were evaluated at 1- and 4-months post-surgery. Statistical analysis investigated the responsiveness of outcome measures and association of physical measures with the Palmar Pain Severity Scale (PPS). 21 participants enrolled prior to premature study closure due to the COVID-19 pandemic; 13 completed follow up. Scar pain (p=.002); scar interference (PPI [p=.009]) and Brief Pain Inventory (BPI) scores (p=.03) improved. Neuropathic Pain Symptom Inventory (NPSI) scores demonstrated heterogeneity in scar pain; evoked pain predominated. Patient Scar Assessment Questionnaire (PSAQ) indicated improvement in cosmetic dissatisfaction and consciousness (p=.03; p=.003), respectively. Baseline psychological screening scores correlated with scar pain (p=.04), and interference (p< .001). Scar morphology, pliability and inflammation were not associated with scar pain. Significant differences in scar mechanical pain sensitivity (p=.04) and cold pain threshold (p=.05) were identified. PPS and PPI scores were responsive in a heterogeneous hand surgery sample. BPI worst pain identified severe pain, suggesting composite scar pain scores are required. The PSAQ robustly measured scar appearance and consciousness. Psychophysical tests of mechanical and thermal sensitivity are potential candidate objective measures of scar hyperesthesia. The NPSI demonstrates clinical utility for exploring scar pain symptoms and may support the elucidation of the drivers of persistent scar pain.