Fractional carbon dioxide laser for treating hypertrophic scars: A systematic review of randomised trials

Hypertrophic scars present collagen deposition and an abnormal extracellular matrix that cause abnormal shape changes and limit normal movement. Although fractional carbon dioxide (CO₂ ) laser therapy has provided promising evidence, the improvement of scarring has not been thoroughly reviewed. A systematic review of prospective randomised trial articles collected from PubMed, MEDLINE, EMBASE, Cochrane and Scopus databases was conducted on 15 March 2020 in accordance with the PRISMA-P statement. Types and duration of fractional carbon dioxide laser used in this study along with the comparative modalities were recorded in this review. Treatment efficacy was assessed as the primary outcome. Adverse events and patient satisfaction were assessed as the secondary outcome. Five prospective randomised studies were included in this study. All studies included showed a consistent result with a conclusion that CO₂ fractional laser treatment demonstrated statistically significant improvement for various scar scoring methods. Combination with other modalities may yield better results in some studies with the risk of more severe adverse events. Temporary side effects such as itching or burning sensation, erythema and oedema were present but appeared to be minimal and well tolerated. Overall patients reported significant improvement in quality of life. Some of the studies are uncontrolled with relatively short-term follow-up. Controlled comparative studies within the same scar with larger sample size and longer follow-up period are required. This evidence suggests that fractional CO₂ laser treatment is effective for improving the clinical appearance of hypertrophic scars with a good safety profile.