Computer modeling of radiofrequency thermocoagulation (RF- TC) using the recording intracerebral electrodes implanted for stereo electroencephalography (SEEG) monitoring

Our objective was to use computational modeling to provide a full and comprehensible physical description of the electrical and thermal behavior during electroencephalography-guided radiofrequency thermocoagulation (SEEG-RF-TC), a minimally invasive procedure to destroy epileptic foci in the brain. We used the Finite Element Method to solve a coupled electrical- thermal problem and obtain the temperature distributions in the tissue for a constant power thermocoagulation. We found that 5 W provokes an impedance roll-off (abrupt increase) after approximately 10 s, and that this is related to temperatures of 100 ºC in the surroundings of the contacts. Due to the internal resistance associated with the wires of the electrode, self- heating provoked a temperature increase of up to 3.3 ºC throughout the device. Our findings should alert clinicians who are guided by impedance during SEEG-RF-TC regarding overheating associated with roll-off. The self-heating (approximately 3 ºC) occurring along the electrode should also be taken into account as it could provoke thermal side-effects.