Between 1993 and 1999, 41 patients were indicated for invasive EEG examination and 49 electrode implantations were performed at our department. This group of patients consisted of 25 males and 16 females aged 18 to 49, median 30 years. The depth and strip electrodes were implanted during 31 investigations, only strip electrodes during 6 investigations and foramen ovale electrodes during 12 investigations. During the whole diagnostic process following clinical complications were observed: asymptomatic haematoma in 2 cases (4.1 %), meningitis in 1 case (2.0 %) and febrilia in 2 cases (4.1 %). Based on the results of an invasive EEG study, epilepsy surgery was indicated in 29 cases (59.2 %) and it was performed in 26 patients. In this group treatment was successful in 14 cases (58.3 %), partial success was recorded in 7 patients (29.2 %). Treatment was unsuccessful in 3 cases (12.5 %) and in 2 other cases the follow up was too short so far. The analysis proves that the stereotactic implantation of electrodes causes no serious or permanent complications and in the majority of patients invasive EEG monitoring leads to an indication of epilepsy surgery.

        Key words: stereotaxis, epilepsy, invasive EEG, epilepsy surgery