Abstract
Early epilepsy is a well-documented complication after aneurysm operations, but the mechanism is not well clarified. After aneurysm clipping, CSF drainage equipped with electrodes was inserted around aneurysm in 25 cases in which 20 patients were operated on within 48 hours after onset of subarachnoid hemorrhage and 3 during the chronic stage. Two cases had unruptured aneurysms. Both scalp and depth EEGs were continuously monitored for 7 to 14 days after operation. In these 25 cases, anticonvulsant was given in only one case.
Three types of EEG abnormalities were recorded. Type A: Spike or sharp wave localized to deep recordings and not observed from scalp EEGs. The peak of spike incidence was day 1 or 2 after operation in cases of less prominent SAH on preoperative CT. In cases of massive SAH, an increase of spike incidence was observed. Type B: Sustained paroxysm localized to deep recordings. This was recorded in 7 cases from day 2 to 13. In 5 cases, prominent SAH was observed on CT. Type C: Secondary generalization of seizure discharges was observed in 2 cases with massive SAH. Epileptiform discharges started from deep recordings. Administration of VPA did not prevent occurrence of type A discharge. These results suggest that early epilepsy after aneurysm operation may originate in the infero-medial part of the frontal or temporal lobe damaged by either SAH per se or surgical manipulation. Possible mechanisms of postoperative epilepsy after aneurysm operation and indication of prophylactic administration of anticonvulsant are in this paper.
