Parameter analysis in stereoelectroencephalography-guided radiofrequency thermocoagulation: A common basis for objective comparison between protocols.

Objective: Stereoelectroencephalography-guided radiofrequency thermocoagulation (SEEG-guided RF-TC) is an invasive procedure based on stereotactic lesioning of cortical targets in the brain using bipolar current through electrode contacts within the SEEG implant. To date, several RF-TC protocols have been described in the literature; however, a consensus has yet to be reached. This work aims to analyze the electrical parameters during RF-TC processes, offering a method to objectively describe and compare different SEEG-guided RF-TC protocols.

Methods: The study included patients who underwent RF-TC procedures at the IRCCS Istituto delle Scienze Neurologiche di Bologna from February 2022 to May 2023. During each procedure, modifications of the following parameters were measured: voltage, current, impedance, and electric power. An ad-hoc algorithm was implemented to detect abrupt impedance raises, which reflects the occurrence of the thermocoagulation. A two-sample t-test was used to compare parameter curves in RF-TC of different brain structures.

Results: A total of ninety-two RF-TC procedures were performed in eight patients according to a standardized protocol. During each procedure, impedance levels started at about 700Ω and rose up to 1300Ω, displaying an erratic pattern characterized by one or multiple raises. All measured parameters exhibited similar trends until the first peak, after which changes were influenced by the frequency of impedance raises. No significant correlations were observed between parameter modifications in distinct anatomical sites of RF-TC.

Significance: The systematic analysis of electrical parameters may represent a reliable tool to compare different RF-TC protocols, paving the way for identifying optimal configurations for SEEG-guided RF-TC procedures in the future.