Enhancing diagnostic accuracy in presurgical evaluation: invasive recordings with a combination of subdural grids plus depth electrodes

Introduction: Patients suffering from intractable focal epilepsy due to focal cortical lesions are often considered suitable for surgery. Complete removal of the lesion and the ictal onset zone are accepted as crucial for a favorable postoperative outcome. A significant portion of the lesions extends into juxtacortical areas and is insufficiently recorded by superficial subdural grids. Objective: In our center depth electrodes (DE) were implanted into the lesions to achieve improved definition of the epileptogenic cortex in addition to subdural grid electrodes (SGE) since september 2009. We evaluated the feasibi…