Experimental and theoretical study of an internally cooled bipolar electrode for RF coagulation of biological tissues.

Although some types of bipolar electrodes have been broadly employed in clinical practice to coagulate biological tissue by means of radiofrequency (RF) currents, there is still scanty available information about their electrical-thermal behaviour. We are focused on internally cooled bipolar electrodes. The goal of our study was to know more about the behavior of this kind of electrodes. For that, we planned an experimental and theoretical model. The experimental study was based on bovine hepatic ex vivo tissue and the theoretical model was based on the Finite Element Method (FEM). In order to check the feasibility of the theoretical model, we assessed both theoretically and experimentally the effect of the internal cooling characteristics of the bipolar electrode (flow rate and coolant temperature) on the impedance progress during RF heating and coagulation zone dimensions. The experimental and theoretical results were in good agreement, which suggests that the theoretical model could be useful to improve the design of cooled bipolar electrodes.