StereoEEG in Diagnosis of Pharmacoresistant Epilepsy

Introduction StereoEEG is a procedure of placing intracerebral depth electrodes with multiple contact points in patients suffering from pharmacoresistant epilepsy. The procedure is used in cooperation with the neurology department, UH Dubrava, for the diagnostic purposes of locating the focus point of epilepsy that could not be verified or visualized on noninvasive diagnostic procedures. Our experience so far involves 5 patients that have been treated and 58 implanted electrodes, which is on average 11.6 electrodes per patient. The procedure is performed stereotactically with preoperatively attached Leksell stereotactic frame. Patient's preoperative brain MRI is merged with a CT scan obtained after the attachment of stereotactic frame. Usually, 11 electrodes are implanted in specific points of the brain which are predetermined and planed together with our epilepsy specialists. After implantation of the intracranial depth electrodes, doses of antiepileptic drugs are gradually decreased and eventually stopped to increase the likelihood of recording seizures. The patient is monitored, and when the likely epileptogenic focus is verified, depth electrodes are removed and further treatment modality is discussed and presented to the patient.

Aim We have concluded that SEEG, although invasive, is the method of choice in patients which have intractable epilepsy without known epileptogenic zone. When it is adequately planned and performed, it is safe and reliable, for, in all patients, the epilepsy focus was found and subsequently treated, which is the main goal of stereoEEG. Our intention is to further perfect the procedure so the rate of possible complications is reduced to minimum.

Keywords StereoEEG; pharmacoresistant epilepsy; epileptogenic focus