ガンマナイフ手術により治療された成人と小児の脳動静脈奇形の比較

The Comparison between Adult and Pediatric AVMs Treated by Gamma Knife Radiosurgery

I．はじめに

　Steinerら^15）が，1972年に初めてガンマナイフ手術により脳動静脈奇形（AVM）を治療して以来，20年以上が経過し，これまでに多くの治療成績が報告されてきた^{1,9,11,13,16,17）}．

　われわれは，1991年5月より1994年9月までに290例のAVMをガンマナイフ手術により治療し，この中1年間以上の経過で脳血管撮影にて追跡調査されたのは99例であった．これらの症例を成人（16歳以上）と小児に分けて，脳動静脈奇形の特徴，ガンマナイフ手術後のAVMの閉塞率，副作用等について検討したので報告する．

More than 290 cases of cerebral AVM had been treat-ed by gamma knife radiosurgery since May, 1991, among which ninety-nine cases were angiographically followed up for at least one year. Comparison of the re-sults between adult and pediatric AVMs were made.

There were seventy six adult and twenty three child cases. Intracerebral hemorrhages in their past history were found in 73.7% of adult and 91.3% of child cases respectively, and the rate of intracranial hemorrhages in the pediatric group was higher than that in the adult group. The volume of the nidus of AVM in both groups was 4.2 ml in adults and 4.8 ml in children.Grade Ⅲ of the Spetzler grading system occupied a-bout 70% of all cases and was the most common grade in both groups. Treatment was performed with a mean marginal dose of 20.0Gy in adults and 20.5Gy in chil-dren.

The complete occlusion of the nidus was obtained in 45% of the adult group and 74% of the pediatric group one year after, and in 81% and 95% respectively two years after the treatment was begun. As side effects, these were two rebleedings, one radiation necrosis and one radiation-induced edema in adults. However, no side effects were observed in chil-dren.

It is considered that, when using gamma knife radiosurgery, pediatric AVMs are more likely to be occluded successfully and safely than adult AVMs.