Dynamic Evaluation of Microwound Healing Induced by a Fractional CO₂ Laser Using Reflectance Confocal Microscopy

A model for evaluating the in-vivo skin wound healing process over time is needed. Wound healing can be evaluated using reflectance confocal microscopy (RCM), which permits the dynamic characterization of the skin in a noninvasive manner.

The aim of this study was to analyze the healing process of fractionally induced microwounds using RCM.

Eight healthy volunteers had a fractional carbon dioxide (CO₂) laser applied to the healthy skin of their inner arm in a single session. The wound healing of the skin at the stratum spinosum and stratum basale layers was examined using RCM. Two dermatologists evaluated the changes in the ablative zone using a grading system (ranging from completely recovered to slightly enlarged ablative zone) at four temporal time points: 3, 7, 14, and 28 days after laser application.

The ablative zone in the epidermis was 75 percent of the baseline after seven days and 25 percent of the area after 14 days compared to the baseline. The expanded ablative zones in the epidermis were observed in some subjects resulting from contraction between Day 3 and Day 7. The ablative zone completely healed 28 days after laser application in both the spinous and basal layers of the epidermis.

The healing process in the ablative zone of the fractional CO₂ laser-induced microwounds was observed over 2 to 4 weeks, revealing a regenerated epidermis of replaced keratinocytes from the basal layer through RCM.