Long term effects of Gamma knife Radiosurgery for treatment of cerebral arteriovenous malformations

 Abstract Background: The Gamma Knife Radiosurgery (GKR) is an established management option for Cerebral Ar-teriovenous Malformations (AVMS). Therapeutic benefits of radiosurgery for arteriovenous malformations are complete obliteration of nidus with minimal neurological deficit. Methods: Radiosurgery was performed between February 2003 and April 2010 at Kamraniye day clinic, Teh-ran, Iran, using the Leksell gamma knife model B (Elektra Instruments AB, Stockholm, Sweden) on 82 consecu-tive patients with AVMs. The male-to-female ratio was 1.4:1(48M, 34F). The age of the patients ranged from 9 to 70 years (mean, 28.5±12 years). The marginal dose to the AVM nidus was 45 to 85% (median, 60%) isodose and ranged from 14 to 30 Gy (mean, 20.57±13Gy).The maximum dose ranged between 20 to 60 Gy (mean, 37.5 Gy ± 10.17Gy ). Follow up of patients for complete AVM obliteration and in the case of complications MRI were performed. Results: Complete obliteration of AVM was achieved in 56 cases (68.29%). It was marked in average 3.62 [SD=3.19] years (from 1 to 5 years) after GKR. Partial obliteration (≥50% reduction of the nidus volume) was marked in 24 cases(31%), and less than 50% reduction of the nidus volume was marked in 2 cases(2.4%) with a follow-up of 5 years. Complete obliteration of AVM had statistically significant associations with smaller score of Spetzler-Martin arteriovenous malformation grading system for AVMs. (p< 0.05) Conclusion: The Gamma Knife Radiosurgery can offer total and partial obliteration to acceptable percent of treated AVM with a low risk of morbidity. Higher success observed in patients with Spetzler-Martin Grade I and II AVMs, which was attributed to smaller volume of AVMs in this group.