Seizure outcomes after stereotactic radiosurgery for the treatment of cerebral arteriovenous malformations

Abstract

OBJECTIVE Patients with cerebral arteriovenous malformations (AVMs) commonly present with seizure. Seizure outcomes in patients treated with stereotactic radiosurgery (SRS) are poorly defined. A case series of patients with cerebral AVMs treated with SRS is presented to evaluate long-term seizure outcome. METHODS A retrospective review of the medical record was performed, identifying 204 consecutive patients with AVMs treated with SRS between January 1991 and June 2012. Clinical and radiographic data were evaluated. Seizure outcome was measured using the Engel Epilepsy Surgery Outcome Scale. Mean duration of follow-up was 37.1 months (SD 38.3 months) with a minimum follow-up period of 1 month. RESULTS Of the 204 patients with cerebral AVMs treated with SRS, 78 patients (38.2%) presented with seizures and 49 of those patients were treated with antiepileptic drugs (AEDs). Following SRS, 63 (80.8%) of the 78 patients who had had seizures prior to SRS were seizure-free at a mean follow-up time of 37.2 months (SD 41.3 months). Of the 49 patients who had been treated with AEDs, 17 were still taking AEDs at last follow-up. Of the 126 patients who did not present with seizures prior to treatment with SRS, only 5 patients (4.0%) had seizures in the post-SRS period. There was no significant correlation between post-SRS seizure status and patient demographic features, comorbidities, AVM characteristics, history of operative intervention, pre- or posttreatment hemorrhage, or radiographic degree of AVM resolution. CONCLUSIONS Stereotactic radiosurgery for treatment of cerebral AVMs is effective at providing long-term control of seizures. A substantial number of patients who were treated with SRS were not only seizure free at their last follow-up, but had been successfully weaned from antiepileptic medications.

Seizure control after radiosurgery for cerebral arteriovenous malformations: a 25-year experience

“…However, two studies published after the one by Chen et al 4 that included 151 total patients demonstrated that AVM obliteration does not necessarily predict seizure outcomes. 7,30 In our study, we observed that seizure remission was not significantly associated with AVM obliteration, suggesting that SRS provides at least some seizure control via radiation to the surrounding tissue. 4,12,15 Although not well understood, it has been suggested that perinidal radiation provides seizure relief through multiple mechanisms, including inhibition of protein synthesis, neuromodulatory effects on local inhibitory and excitatory neurons, perinidal gliotic capsule formation, dendritic sprouting, and cortical reorganization.…”

“…Of note, our results indicate that the proportion of patients reaching freedom from maintenance AED therapy (18%) was lower than that reported in previous studies. 7,30,39 In general, our approach has been to attempt to wean patients off AEDs after 2 years of seizure freedom. 4 Nonetheless, we found that many patients were maintained on 1 AED despite AVM obliteration and seizure freedom for > 2 years.…”

“…Indications for SRS in the management of seizures have thus depended on nonrandomized case series, which have been limited by small sample size, short followup duration, and inadequate review of the AED regimen. 4,7,11,12,15,23,30,32,34 In the current study, we describe longterm seizure outcomes in a large observational cohort of SRS-treated AVMs in patients presenting with seizure. Additionally, we characterize the temporal course of post-SRS seizures and identify prognostic pre-SRS, intra-SRS, and post-SRS factors associated with long-term seizure control.…”

Results of volume-staged fractionated Gamma Knife radiosurgery for large complex arteriovenous malformations: obliteration rates and clinical outcomes of an evolving treatment paradigm

“…Considering the inherent difficulty of achieving a complete obliteration for such challenging lesions, seizure control and prevention of neurological deficit progression are key objectives in the radiosurgical treatment of large AVMs. The dramatic positive effect of radiosurgical treatment on seizure outcome has been previously reported to be up to 80% 4,7,24,33 and related to obliteration. This also holds true for large cerebral AVMs, as we reported 50% of patients to be seizure-free (Engel Class I) and 25% to have a significant reduction in epileptic episodes (Engel Class II), thereby achieving an overall good outcome in seizure control for 75%.…”

Recent advances in epilepsy

“…Radiosurgery for arteriovenous malformations may give excellent outcomes for associated epilepsy and positive prognostic factors have been reported to be presentation with haemorrhage rather than epilepsy and the absence of post-treatment haemorrhage [163–165]. A recent meta-analysis of stereotactic radiosurgery for mesial temporal sclerosis [166] showed that the total number of patients reported remains low (<200) but that half became seizure free at a median of 14 months after treatment with a complication rate of around 8% (excluding headache which was more common) and rates of visual field defects similar to open surgery.…”