Thermoelectrical Modeling of Bipolar Coagulation on Posterior Spinal Artery in a Porcine Spinal Surgery Model

The primary objective of our study was to develop a thermoelectrical model with both solid and liquid phases to calculate tissue temperature during bipolar coagulation of a posterior spinal artery on the spinal cord. Control of thermal spread caused by coagulation is a concern in spinal surgery. This model utilizes a nonisothermal flow to account for the heat transfer due to the movement of cerebrospinal fluid that is induced by electrical field and temperature gradient. The model is validated by in situ temperature measurements on a porcine spinal cord model. The maximum error for tissue temperature of this model is 12.6%, and the overall average error is 4.2%. The lesional region (>50°C) is identified to be as wide as 5 mm, and thermal dose cumulative equivalent minutes at 43°C (CEM 43) is also calculated with this model. The incorporation of nonisothermal flow has been shown to be crucial in order to accurately predict thermal dose in tissue. The developed model can be further used to establish a guideline for the use of bipolar coagulation.