56 Treating Hypertrophic Burn Scar with 2940 nm Erbium: YAG Laser Fractional Ablation Improves Scar Characteristics as Measured by Noninvasive Technology

Abstract

Fractional laser resurfacing (FLR) with the CO2 laser has been shown by subjective rater systems to be effective for treating hypertrophic burns scars (HBS). However, recent literature in animal burn models has demonstrated superior effects of the erbium: yttrium aluminum garnet (Er:YAG) laser over its CO2 counterpart. To date, few studies have explored Er:YAG treatment of HBS, and none have used objective measurements. In a prospective study, we used an Er:YAG laser on HBS and measured the results with noninvasive, objective technologies. Patients with HBS and no prior FLR had a region of scar to be treated by the Er:Yag laser (TREAT) and a comparable, non-treated, control region (CONTROL). We prospectively collected scar measurements of TREAT and CONTROL regions pre-operatively, 3 weeks, and 3 months after FLR. Scar measurement devices are demonstrated in Figure 1. A separate linear mixed model analysis of multivariate (doubly) repeated measures evaluated the effect of FLR on each outcome, controlling for patient age, scar age, and sex. Seventeen patients were seen preoperatively, followed by 15 at 3 weeks and 11 at 3 months. The mixed model repeated measures analysis showed no significant treatment or treatment by time interaction effect for any measurements; however, demonstrated significant within-subject time period effects for viscoelastic deformity (p=0.03), elastic deformity (p=0.004), skin roughness (p=0.05), and wrinkle depth (p=0.04). The pattern of the least squares means (LSM) showed these aforementioned outcomes significantly increased over the 3-month assessment period for TREAT but not for CONTROL regions (Table 1). No significant differences were seen in scar epidermal thickness, dermal thickness, stiffness, transepidermal water loss, or blood flow. In a subset of six patients, no differences were seen in histological analysis over the study period. Improvement in HBS treated by Er:YAG FLR were seen within-subjects in objective, noninvasive scar measurements over 3 months. Future work will focus on developing longer, multi-center trials to further determine the effects of Er:YAG on HBS. Pattern of least squares means across assessment periods within TREAT and CONTROL regions LSM = least squares means, SE = standard error The P value is associated with the test of the overall within-subjects LSM differences on the outcomes between the repeated measures across the three time points. Pattern of least squares means across assessment periods within TREAT and CONTROL regions LSM = least squares means, SE = standard error The P value is associated with the test of the overall within-subjects LSM differences on the outcomes between the repeated measures across the three time points.