Water flux from partial-thickness skin wounds: Comparative study of the effects of Er:YAG and Ho:YAG lasers

Background and Objective: The clinical use of lasers to cut and coagulate tissue necessitates a better understanding of how the residual thermal damage affects healing. This study was designed to evaluate the effects of varying degrees of thermal damage on the healing process. Study Design, Materials and Methods: Partial-thickness lesions were created in guinea pig skin using an Er:YAG laser, a Ho:YAG laser, and a scalpel. To monitor recovery of the stratum corneum, water flux from the wound sites was quantified and histological data obtained for approximately one week. Results: The data indicate an exponential water loss pattern from all wounds. Water flux from the scalpel- and the Er:YAG laser-induced wounds was initially high but decreased rapidly with decay rates (mean ± SE) of 0.46±0.01 day^-1 and 0.38±0.01 day^-1, respectively. The Ho:YAG laser-induced wounds demonstrated a different pattern of decay with lower water flux values initially and a decay rate of only 0.13±0.01 day^-1. Conclusion: Histological and water flux data reveal that Er:YAG laser-induced wounds achieve epidermal integrity only slightly after scalpel-induced lesions, and Ho:YAG laser-induced wounds heal substantially slower and contain more granulation tissue.