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

OBJECTIVE There are few reported series regarding volume-staged Gamma Knife radiosurgery (GKRS) for the treatment of large, complex, cerebral arteriovenous malformations (AVMs). The object of this study was to report the results of using volume-staged Gamma Knife radiosurgery for patients affected by large and complex AVMs. METHODS Data from 20 patients with large AVMs were prospectively included in the authors' AVM database between 2004 and 2012. A staging strategy was used when treating lesion volumes larger than 10 cm3. Hemorrhage and seizures were the presenting clinical feature for 6 (30%) and 8 (40%) patients, respectively. The median AVM volume was 15.9 cm3 (range 10.1–34.3 cm3). The mean interval between stages (± standard deviation) was 15 months (± 9 months). The median margin dose for each stage was 20 Gy (range 18–25 Gy). RESULTS Obliteration was confirmed in 8 (42%) patients after a mean follow-up of 45 months (range 19–87 months). A significant reduction (> 75%) of the original nidal volume ...