Within-Patient, Single-Blinded, Randomized Controlled Clinical Trial to Evaluate the Efficacy of Triamcinolone Acetonide Injections for the Treatment of Hypertrophic Scar in Adult Burn Survivors

Abstract

Intralesional corticosteroid (triamcinolone acetonide [TAC]) injections 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 to evaluate the impact of TAC injections on burn HSc compared with patient-matched usual care control scars. Fifty burn survivors with two scars (separated by nonscarred 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 was outside of the range of normal scar). Pretreatment thickness measurements of the two 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 or control. The treatment HSc received a 10 mg/ml TAC. When necessary, the injection was repeated after 6 weeks and a third final injection 6 weeks later. Objective evaluation of thickness, elasticity, erythema, and melanin was obtained at the treatment and control sites at pretreatment, posttreatment, and follow-up 6 weeks after the last injection. Thirty participants completed the study, reaching the required number for an adequately powered sample based on pilot study data analyses. Ten participants received only one injection, 27 received only two injections, and 13 received three injections of TAC. Analysis of covariance comparing the treatment vs control HSc posttreatment, controlling for pretreatment values and Fitzpatrick skin type, revealed a significant decrease in thickness and increase in elasticity of the treated compared with control HSc (P = .0003), but no significant difference in erythema or melanin. Pretreatment to posttreatment comparisons using paired t-tests revealed a significant decrease in thickness of both the treated and control HSc, an increase in elasticity of the treated HSc during the treatment period, but no significant change in the control HSc elasticity or erythema of either site, and a significant increase in melanin of both the treated (P < .001) and control (P = .02) HSc. A regression model for repeated measures, controlling for pretreatment values and skin type, revealed no significant change in thickness, elasticity, erythema, or melanin during the 6-week follow-up. Although thickness decreased at both the treated and control HSc across time, there was a significantly greater reduction at the TAC injected HSc and a significantly greater increase in elasticity. Melanin significantly increased at both the treatment and control site. There was no significant change during the follow-up period of any of the HSc characteristics.