Prospective analysis of the precision of electrodes implantation in invasive EEG for drug-resistant epilepsy using the VarioGuide®

Details

Supervisors

Raftopoulos, Christian ; Ribeiro Vaz, José Géraldo ; Joris, Vincent ; De Nijs, Loïc

Faculty

Faculté de médecine et médecine dentaire

Degree label

Master [180] en médecine

Abstract

INTRODUCTION: Frameless neuronavigated stereoencephalography (SEEG), inter alia the VarioGuide® system from Brainlab, may represent a timesaving, less expensive alternative to the traditional framebased or robot-guided implantation of intraparenchymal electrodes. METHODS: The prospective analysis included all patients with refractory epilepsy that underwent electrode implantation in our center (Cliniques universitaires Saint-Luc) between March 2019 and December 2020. The primary outcome was the implantation accuracy, determined by calculating the Euclidean distance between planned and in vivo trajectory. For each trajectory, intracranial length, entry angle, bone thickness, soft tissue thickness and entry angle were determined. A linear regression model was used to evaluate their predictive strength with regard to the outcome. Categorical variables such as the target, the approach, as well as the surgeon also were investigated. Secondary outcomes were the surgical duration, the major and minor complications, and the clinical usability of the data. RESULTS: Twenty-three patients underwent implantation of 216 depth electrodes in total. Mean accuracy was 4,62 mm +- 2,64 mm (standard deviation) for the entry point and 4,34 mm +- 2,36 (standard deviation) for the target point. The chosen trajectory which depended upon the approach and target, as well as the intracranial length were shown to significantly influence the accuracy. The mean operating time was 180 minutes, corresponding to approximately 20 minutes/electrode. Seven out of 23 patients had minor complications, 5 of them were asymptomatic or slightly symptomatic hematomas with spontaneous resorption. We had no major complications. CONCLUSION: Compared to the existing literature, the VarioGuide® system proved to be moderately accurate but successful, timesaving and kept complication rates within acceptable bounds.