Measurement Of Tissue Thermal Conductivity With Variable Thermal Dose During An Electrosurgical Joining Process

Electrosurgical vessel joining is commonly performed in surgical procedures to maintain hemostasis. This process requires elevated temperature to denature the tissue and while compression is applied, the tissue can be joined together. The elevated temperature can cause thermal damages to the surrounding tissues. In order to minimize these damages, it is critical to understand how the tissue properties change and how that affects the thermal spread. This study used porcine aorta arterial tissue to investigate tissue thermal conductivity with variable thermal dose. Seven joining times (0, 0.5, 1, 1.5, 2, 4, and 6 seconds) were used to create different amounts of thermal dose. A hybrid method that uses both experimental measurement and inverse heat transfer analysis was conducted to determine the thermal conductivity of thin tissue samples. In general, the tissue thermal conductivity decreases when thermal dose increases. Accordingly, 36% decrease in tissue thermal conductivity was found when the thermal dose reaches the threshold for second-degree burn (with 2-second joining time). When thermal dose is beyond the threshold of third-degree burn, the tissue thermal conductivity does not decrease significantly. A regression model was also developed and can be used to predict tissue thermal conductivity based on the thermal dose.