T3 Randomized, Controlled, Within-patient, Single-blinded Study to Evaluate the Efficacy of Corticosteroid Injections for the Treatment of Hypertrophic Scar in Adult Burn Survivors

Abstract

Abstract Introduction Intralesional corticosteroid injections (CSI) have become one of the cornerstone treatments of hypertrophic scar (HSc). However, the evidence is of limited-quality and published investigations have almost exclusively been performed in linear scars rather than hypertrophic burn scars. Thus, the aim of this study was to perform an appropriately powered, single-blinded, randomized controlled trial (RCT) to evaluate the impact of CSI on burn HSc compared to patient-matched control (C) scars. Methods Fifty burn survivors with 2 independent scars (separated by non-scarred skin preferably on the contralateral side or an anatomically similar site) were selected based on high-frequency ultrasound thickness (>2.034 mm to ensure that the site were outside of the range of normal scar). Baseline thickness measurements of the 2 sites were within 0.5 mm of each other, to ensure homogeneity and an erythema index >300 to establish they were immature HSc. The sites were randomly assigned to treatment (Tx) or C. The Tx HSc received a 10 mg/ml CSI. The CSI was repeated 6 weeks later and a 3rd final injection 6 weeks later if deemed necessary. Objective evaluation of thickness, pliability, erythema and melanin were obtained at the Tx and C sites at baseline, end of Tx and 6 weeks after the last injection. Thirty one participants completed the study, reaching the required number for an adequately powered sample based on pilot study data analyses. Results The mean number of injections per site was 2.1(±0.7 SD). An ANCOVA comparing the Tx vs C post-Tx, controlling for baseline and Fitzpatrick skin type, revealed a significant decrease (↓) in thickness and increase (↑) in pliability of the Tx compared to C HSc (p=0.0003), but no significant difference in erythema or melanin. Baseline to post-Tx comparisons using paired t-tests revealed significant ↓ in thickness of both the Tx and C HSc and ↑ in pliability of the Tx HSc during the Tx period, but no significant change in C HSc pliability or erythema. Wilcoxon Signed Rank Test revealed a significant ↑ in melanin of both Tx (p< 0.001) and C (p=0.0035) HSc. A regression model for repeated measures, controlling for baseline and skin type, revealed no significant change in thickness, pliability, erythema or melanin during the 6 week follow up. Conclusions Although HSc thickness ↓ at both the Tx and C site across time there was a significantly greater reduction at the CSI site and significantly greater ↑ in pliability. Melanin significantly ↑ at both the Tx and C site. There was no significant change during follow up of any of the HSc characteristics. Applicability of Research to Practice This well-controlled RCT demonstrated the benefits CSI for burn HSc thickness and pliability and the need for patient-matched C HSc.