Intractable epilepsy following radiosurgery for arteriovenous malformation- Case report

Radiosurgery is often used to treat arteriovenous malformations (AVMs) loca ted in deep brain locations. Most of these procedures are successful not on ly in obliterating the AVM but also in decreasing the frequency and severit y of associated seizures. Although radiosurgery is occasionally associated with the development of easy-to-control seizures immediately postoperativel y, there have been no reports of intractable epilepsy developing after radi osurgery. In this report, however, a case is presented in which a patient u nderwent gamma knife surgery (GKS) for an AVM, after which intractable epil epsy and mesial temporal sclerosis (MTS) gradually developed. A 37-year-old right-handed woman underwent GKS for a right mesial parietote mporooccipital AVM. One year later, the AVM had reduced in size, but the pa tient began to experience complex partial seizures (CPSs). These CPSs initi ally occurred at a frequency of one per month, but 6 months later they were occurring every other week. She also started having secondarily generalize d tonic-clonic seizures (GTCSs) once per month. Over the next year the freq uency of her seizures gradually increased to several CPSs per day and two t o three GTCSs per week, despite treatment with various combinations of anti epileptic drugs. By this time her AVM had decreased to one half of its orig inal size. Video-electroencephalography monitoring demonstrated that both t he CPSs and GTCSs were arising from the right posterior quadrant. Magnetic resonance imaging revealed not only the presence of the right-sided AVM, bu t also right-sided MTS. The patient underwent surgical resection of the AVM and right temporal lobectomy. She has been free from seizure for longer th an 1 year. Radiosurgery may be associated with intractable epilepsy and MTS.