Seizure control after radiosurgery on cerebral arteriovenous malformations.

Among 462 cases of cerebral arteriovenous malformation (AVM) treated with gamma-radiosurgery, the initial presentations were haemorrhage in 68%, epilepsy in 12.8%, neurological deficits in 3.2%, minor symptoms in 7.6% and asymptomatic in 4.5% respectively. There were 79 cases (17.1%) who had had a convulsive seizure before radiosurgery and they were classified into two groups: 58 cases presented with seizure as an initial symptoms (group A) and the other 21 cases mostly had seizures following intracranial haemorrhage (group B). Before radiosurgery, generalised seizure was the predominant seizure pattern in both groups, followed by pure partial and complex partial seizures. There was no major difference in seizure patterns or seizure frequency in group A and B. At radiosurgery AVMs were treated with a mean maximum dose of 37.2 Gy and a marginal dose of 19.8 Gy. Seizures had apparently decreased in most of the cases at the last follow-up (mean 24 months) according to the obliteration of the nidus. Seizures were either decreased or had disappeared in 91.6% of group A and 62.5% of group B patients. The overall results indicate that seizures improved in 85.5%, were changed in 11.6% and deteriorated in 2.9% of patients. Radiosurgery is effective not only for the obliteration of nidus of cerebral AVM, but also for seizure control, even before complete occlusion of the nidus.