Volume-staged gamma knife radiosurgery for large brain arteriovenous malformations.

Abstract

OBJECTIVE\nLarge brain arteriovenous malformations (AVM) pose a management dilemma because of the limited success of any single treatment modality by itself. Surgery alone is associated with significant morbidity and mortality. Similarly, embolization alone has limited efficacy. Volume-staged gamma knife radiosurgery (VSGR) has been developed for the treatment of large AVMs, to increase the efficacy and improve safety of treatment of these lesions. The aim of the study was to assess the efficacy and safety of VSGR technique for the treatment of large brain AVMs.\n\n\nMETHODS\nThe study included patients treated by VSGR between May 2009 and July 2015. All cases had large AVMs (>10 ml). These were 29 patients.\n\n\nRESULTS\nTwenty-four patients completed radiographic follow up with 15 obliteration cases (62.5%). There was a total of 56 sessions performed. The mean AVM volume was 16 ml (10.1-29.3 ml). The mean prescription dose was 18 Gy (14-22 Gy). The mean follow up duration was 43 months (21-73 months). One patient died during follow up from unrelated cause. Two cases suffered haemorrhage during follow up. Symptomatic edema developed in 5 (17%) patients. The factors affecting obliteration were smaller total volume, higher dose/stage, non-deep location, compact AVM, AVM score less than 3, >18 Gy dose and <15 ml total volume. The factors affecting symptomatic edema were smaller total volume and shorter time between first and last sessions (p 0.012). T2 image changes were affected by SM grade 3 or more (p 0.013) and AVM score 3 or more (p 0.014).\n\n\nCONCLUSION\nVSGR provides an effective and safe treatment option for large brain AVMs. Smaller AVM volume is associated with higher obliteration rate.