Influence of scar age, laser type and laser treatment intervals on adult burn scars:A systematic review and meta-analysis

Aim: The study aims to identify whether factors such as time to initiation of laser therapy following scar formation, type of laser used, laser treatment interval and presence of complications influence burn scar outcomes in adults, by meta-analysis of previous studies.Methods: A literature search was conducted in May 2022 in seven databases to select studies on the effects of laser therapy in adult hypertrophic burn scars. The study protocol was registered with PROSPERO (CRD42022347836).Results: Eleven studies were included in the meta-analysis, with a total of 491 patients. Laser therapy significantly improved overall VSS/POSAS, vascularity, pliability, pigmentation and scar height of burn scars. Vascularity improvement was greater when laser therapy was performed > 12 months (-1.50 [95%CI = -2.58;-0.42], p = 0.01) compared to < 12 months after injury (-0.39 [95%CI = -0.68; -0.10], p = 0.01), the same was true for scar height ((-1.36 [95%CI = -2.07; -0.66], p < 0.001) vs (-0.56 [95%CI = -0.70; -0.42], p < 0.001)). Pulse dye laser (-4.35 [95%CI = -6.83; -1.86], p < 0.001) gave a greater reduction in VSS/POSAS scores compared to non-ablative (-1.52 [95%CI = -2.24; -0.83], p < 0.001) and ablative lasers (-0.95 [95%CI = -1.31; -0.59], p < 0.001).Conclusion: Efficacy of laser therapy is influenced by the time lapse after injury, the type of laser used and the interval between laser treatments. Significant heterogeneity was observed among studies, suggesting the need to explore other factors that may affect scar outcomes