小さな脳動静脈奇形の自然歴 : ガンマナイフ治療を施行した2000例の初回出血の検討  [in Japanese] Natural History of Small Cerebral Arterial Venous Malformations : Analysis of 2000 Cases Treated with Gamma Knife Surgery  [in Japanese]

We analyze 2000 cerebral arteriovenous malformations (AVMs) to ascertain the cumulative bleeding-free survival and prognostic factors. All cases in this study had small AVMs (3cm or less) and were treated with gamma knife (GK) surgery, at 6 institutes located throughout central and eastern. The median age at GK surgery was 37 years, range 4 to 84. There were 1168 men and 843 women. The Speztler-Martin grade was 1 in 488, 2 in 822 and 3 in 701. In 1066 AVMs, clinical symptoms of bleeding were recorded. The annual bleeding rate was 1.46% (overall) and 3.083% with bleeding by the person-year's method. Bleeding was observed more frequently in women than in men, especially in women of reproductive ages. Neither the volume nor the location of AVMs was a significant predictor of bleeding. This large data-base is expected to provide useful information regarding the natural history of small AVMs that can be effectively treated with GK surgery.