Carbon Dioxide Fractional Laser Versus Micro‐Plasma Radiofrequency for Hypertrophic Scar: A Two‐Center, Open‐Label, Randomized, Split‐Scar Study

ABSTRACT Objective The aim of this study is to compare the effect and safety of carbon dioxide fractional laser (CDFL) and micro‐plasma radiofrequency (MPRF) for the treatment of hypertrophic scars (HSs). Methods Symmetric HSs were divided into two sides and randomly treated with either MPRF or CDFL. The Vancouver Scar Scale (VSS), Patient and Observer Scar Assessment Scale (POSAS), shear wave elastography (SWE), and optical coherence tomography angiography (OCTA) were used to compare the changes between baseline and 1 month after the third treatment. The co‐primary outcome was the difference in the score of VSS and POSAS. Results VSS and POSAS assessments indicated that CDFL primarily improved scar color and vascularity, while MPRF mainly improved scar thickness, elasticity, and hardness. OCTA demonstrated greater changes with CDFL than with MPRF in average vascular diameter (CDFL, 45.84 ± 7.68 μm; MPRF, 32.52 ± 10.92 μm; p < 0.0001), density (CDFL, 0.385 ± 0.065; MPRF, 0.291 ± 0.082; p = 0.0166), and complexity (CDFL, 0.217 ± 0.046; MPRF, 0.145 ± 0.349; p < 0.0001). SWE confirmed greater changes with MPRF than with CDFL in thickness (CDFL, 0.079 ± 0.033 cm; MPRF, 0.102 ± 0.046 cm; p < 0.0001) and EM (CDFL, 9.97 ± 6.89 kPa; MPRF, 17.54 ± 9.35 kPa; p < 0.0001). No significant complications were recorded. Conclusion Both CDFL and MPRF were effective and safe for the treatment of HS, but they improved different scar domains. CDFL produced greater improvement in scar color and vascularity by reducing vascular diameter and density, whereas MPRF led to greater improvement in scar thickness and elasticity.