title: The role of intravascular embolization prior to radiosurgery of cerebral arteriovenous malformations. from the standpoint of hemorrhage and early obliteration after gamma knife radiosurgery.
abstract: The role of intravascular embolization prior to radiosurgery of cerebral arteriovenous malformations was evaluated based on the basis of the results of gamma knife radiosurgery in relation to hemorrhage and early obliteration after treatment. Nine of 213 patients experienced hemorrhage 4 to 42 months after radiosurgery. All AVMs in these patients had dilated feeding arteries, and the flow of the AVM was rapid and/or high. An intranidal aneurysm was seen in one patient. Drainage of all AVMs consisted of a single and/or deep draining veins, and venous obstruction was found in six. Sixty-three of 87 patients followed for more than four years after radiosurgery were examined angiographically, and total obliteration of AVM was observed in 52 of them (82.5%). Early obliteration was found in 19 of the 34 patients examined within 12 months. The obliteration rate was significantly higher in slow- and low-flow AVMs (73.9%) than in rapid- and/or high-flow AVMs (18.2%). It is concluded that the role of intravascular embolization prior to radiosurgery is not only decreasing the size of the AVM but decreasing the risk of hemorrhage and shortening the latency period by decreasing their flow rate and flow volume.
authors.affiliation: Department of Restorative Neurosurgery, Institute of Neural Function, Numata Neurosurgery and Heart Disease Hospital; Numata, Gunma, Japan. hkinoue@po.kannet.ne.jp.
authors.forename: H K
authors.initials: HK
authors.lastname: Inoue
authors.forename: Y
authors.initials: Y
authors.lastname: Nagaseki
authors.forename: I
authors.initials: I
authors.lastname: Naitou
authors.forename: M
authors.initials: M
authors.lastname: Negishi
authors.forename: M
authors.initials: M
authors.lastname: Hirato
authors.forename: T
authors.initials: T
authors.lastname: Shibazaki
authors.forename: C
authors.initials: C
authors.lastname: Ohye
authors.forename: Y
authors.initials: Y
authors.lastname: Andou