Safety profile of intracranial electrode implantation for video-EEG recordings in drug-resistant focal epilepsy

Invasive electroencephalography recordings with depth or subdural electrodes are necessary to identify the ictogenic area in some drug-resistant focal epilepsies. We aimed to analyze the safety profile of intracranial electrode implantation in a tertiary center and the factors associated with its complications. We retrospectively examined complications in 163 intracranial procedures performed in adult patients. Implantation methods included oblique depth stereotactic approach (n = 128) and medial–temporal depth stereotactic approach in combination with subdural strip placement (n = 35). 1201 depth macroelectrodes, 59 bundles of microelectrodes (in 30 patients) and 148 subdural electrodes were implanted. Complications were classified as major (requiring treatment or leading to neurological impairment) or minor. The rate of overall complications was 4.9 % (n = 8), with 3.1 % (n = 5) of major complications, though no permanent morbidity or mortality was recorded. Infection occurred in 1.2 % and hemorrhage in 3.7 % of patients. One hemorrhage occurred for every 225 electrodes implanted (4.4 ‰). Microelectrodes were not responsible for any complications. Overall and hemorrhagic complications were significantly associated with MRI-negative cases (7.3 and 6.3 % versus 0 %, p = 0.04). We believe that intracranial electrode implantation has a favorable safety profile, without permanent deficit. These risks should be balanced with the benefits of invasive exploration prior to surgery. Furthermore, this study provides preliminary evidence regarding the safety of micro-macroelectrodes.