Identification of cell thermal microenvironment in porcine skin during laser cauterization

Abstract

In order to minimize bleeding during surgical intervention, laser devices make it possible to produce local heat for cauterization and to reduce the blood loss at the site of the incision in the skin. However, the method is sometimes associated with local overheating and tissue partial vaporization. We present a 3D Finite Element Model (FEM) hierarchical model to simulate the effect of heat produced by different surgical laser devices on the skin. The model includes the macro-molecular, cell and tissue scales. The model follows the bio-heat equation where the transient heat diffusion includes heat conduction in the tissue, convection with the surrounding air, the metabolic heat and the heat source of the laser device. The laser heat flow propagating in the skin was assumed to exponentially decrease from the opening edge of the wound. A set of different lasers were tested on live porcine skin under general anesthesia. The skin morphology of harvested samples along the wound was digitally surveyed in light microscopy observations of the skin specimens that had been previously stained with an anti-swine antibody. The biological constituents of the skin tissue were modeled as separate continua of specific thermal properties taken from the literature in the presented preliminary model. The numerical model evaluated the temperature and the heat flux fields in the vicinity of the laser wound in porcine skin. Using an inverse procedure, these results were validated by comparison with antibody stained tissue images of the experimental samples in order to identify the temperature at which significant damage is experienced by skin cells.