Gamma Knife surgery for clival epidural-osseous dural arteriovenous fistulas

OBJECTIVEClival epidural-osseous dural arteriovenous fistula (DAVF) is often associated with a large nidus, multiple arterial feeders, and complex venous drainage. In this study the authors report the outcomes of clival epidural-osseous DAVFs treated using Gamma Knife surgery (GKS).METHODSThirteen patients with 13 clival epidural-osseous DAVFs were treated with GKS at the authors’ institution between 1993 and 2015. Patient age at the time of GKS ranged from 38 to 76 years (median 55 years). Eight DAVFs were classified as Cognard Type I, 4 as Type IIa, and 1 as Type IIa+b. The median treatment volume was 17.6 cm3 (range 6.2–40.3 cm3). The median prescribed margin dose was 16.5 Gy (range 15–18 Gy). Clinical and radiological follow-ups were performed at 6-month intervals. Patient outcomes after GKS were categorized as 1) complete improvement, 2) partial improvement, 3) stationary, and 4) progression.RESULTSAll 13 patients demonstrated symptomatic improvement, and on catheter angiography 12 of the 13 patients...