Radiosurgery for epilepsy associated with cavernous malformation:: Retrospective study in 49 patients

OBJECTIVE: Microsurgical resection of a cavernous malformation (CM) with or without associated cortical resection can provide efficient treatment of drug-resistant associated epilepsy. To explore the potential alternative role of radiosurgery and to evaluate its safety and efficacy for this indication, we conducted a retrospective multicenter study. METHODS: We retrospectively reviewed the files of patients with long-lasting drug-resistant epilepsy, presumably caused by CM, who were treated by gamma knife (GK) surgery for the control of their epilepsy in five centers (Marseilles, Komaki City, Prague, Graz, and Sheffield). A satisfactory follow-up was available for 49 patients (mean follow-up period, 23.66 +/- 13 mo). The mean duration of epilepsy before the CK procedure was 7.5 (+/-9.3) years. The mean frequency of seizures was 6.9/month (+/-14). The mean marginal radiation dose was 19.17 Cy +/- 4.4 (range, 11.25-36). Among the 49 patients, 17 (35%) had a CM located in or involving a highly functional area. RESULTS: At the last follow-up examination, 26 patients (53%) were seizure-free (Engel's Class I), including 24 in Class IA (49%) and 2 patients with occasional auras (Class IB, 4%). A highly significant decrease in the number of seizures was achieved in 10 patients (Class IIB, 20%). The remaining 13 patients (26%) showed little or no improvement. The mediotemporal site was associated with a higher risk of failure. One patient bled during the observation period, and another experienced radiation-induced edema with transient aphasia. Postradiosurgery excision was performed in five patients, and a second radiosurgical treatment was carried out in one patient. CONCLUSION: This series is the first to specifically evaluate the capability of CK surgery to safely and efficiently treat epilepsy associated with CM. Seizure control can be reached when a good electroclinical correlation exists between CM location and epileptogenic zone. Although we do not recommend CK surgery for prevention of bleeding for a CM that has not bled previously, our findings suggest that GK surgery can be proposed for the treatment of epilepsy when the CM is located in a highly functional area.