Abstracts

Rationale: Stereo-electro-encephalography (SEEG) is an invasive monitoring methodology current used mostly in Europe but under-applied in the US. SEEG implantation can be cumbersome, involving several hours of planning, different imaging modalities and difficult 3D visualization of the implanted electrodes. We describe a novel technique for SEEG implantation, which it has been applied in our center for the last 4 months. Methods: Five patients with medically intractable focal epilepsy underwent stereotactic implantation of depth electrodes in order to (1) better define the epileptogenic zone and to (2) identify possible functional cortical and subcortical areas. All implanted patients were not considered optimal candidates for subdural grid evaluation. Targeting was performed based on intra-operative 3D cerebral angiogram images, which were fused to pre-operative MR and intra-operative fluoroscopy. Stereotatic coordinates were obtained based on a standard stereotactic frame system. After implantation, electricorticograms (EcoGs) were performed to electrophysiologically confirm the correct position of the electrodes. Results: The mean age was 40 year-old. Normal MR was present in 3 patients. The mean number of electrodes implanted was 14. The mean operating time was 6 hours. No complications occurred during implantation or in the post-operative period. The SEEG method was able to identify and delineate the epileptogenic zone and functional brain areas in all studied patients. Four out of five patients had surgical indications for resective surgery based on SEEG data. Conclusions: SEEG is a safe and effective methodology in localizing the epileptogenic and functional areas in the brain. The new technique described is as safe and precise as the standard procedure, bringing simplicity and time efficiency to the method.