Abstracts

Rationale: Despite the remarkable progress of modern neuroimaging some patients with intractable epilepsy require intracranial recording to lateralize or precisely localize the epileptic generator in order to assess candidacy for seizure surgery. In 1977 Talariach and Bancaud reported their technique of stereoelectroencephalography (SEEG). This is a frame-based technique which requires an intra-operative angiogram and is limited to an orthogonal trajectory. Commercial electrodes developed with input from French neurosurgeons are fully MRI compatible. Tailored radiofrequency lesions made through these electrodes prior to removal may obviate the need for craniotomy in some patients. The electrodes may be removed at the bedside. Methods: Olivier at the MNI has perfected a novel technique of SEEG placement without a traditional frame or the need for intra-operative x-rays or angiogram. It allows accurate placement in virtually any trajectory and thus fewer electrodes may be necessary. The electrodes we have been using are not MRI compatible. Radiofrequency lesionectomy through these electrodes has not been attempted. An operative procedure is required for their removal. Results: Experience over the past several years has allowed the adaptation of our method of SEEG placement to commercially available electrodes. This new technique will be demonstrated by intra-operative photographs and post-implantation MRI. Conclusions: With the fusion of these technologies we may: accurately place fewer electrodes, acquire MRI with the electrodes in place, perform radiofrequency lesions, and avoid a second surgery for removal. This advance permits image-guided stereotaxic resection using MRI acquired with the electrodes in place thus ensuring adequate removal of tissue around specific electrodes and/or specific electrode contacts.