前交通動脈動脈瘤とWillis動脈輪前半部の奇形および血流動態

CORRELATION WITH THE ANTERIOR COMMUNICATING ARTERY ANEURYSM AND, THE ANOMALIES AND THE BLOOD CIRCULATION AT THE ANTERIOR PART OF THE CIRCLE OF WILLIS

Ｉ．緒言

　脳動脈瘤の大半はWillis動脈輪に発生するが，そのうち前交通動脈に発生するものは約1／3である。われわれは1969年3月末現在254例の脳動脈瘤を経験し，著者の一人鈴木はうち218例に直接手術を行なっている。そのうち前交通動脈動脈瘤は96例，37.8％で，89例に直接手術を行ない，直接手術率は92.7％である。うち入院中死亡は5例，入院中直接手術死亡率は5.6％である。前交通動脈動脈瘤においてWillis動脈輪前半部の奇形を伴うものが多いことは文献的にもしばしば報告されている^{3）9）10）17）}。われわれの症例においても奇形のあるものがやはり所見上多く，また奇形を伴わない症例でも脳血管写上，一側からだけ両側前大脳動脈が造影される血流動態の異常を伴うものが多かった。そこでわれわれの前交通動脈動脈瘤症例においてWillis動脈輪前半部奇形と血流動態異常の有無につき種々検討を行なつた。その結果，奇形を含めると血流動態の異常がこの部動脈瘤発生の重大な因子となると考えられたので報告する。

On this report the correlation with the aneurysm of the anterior communicating artery and, the anomalies and the blood circulation at the anterior part of the circle of Willis was investigated.

Ninety-six cases of the anterior communicating artery aneurysm were experienced and 89 cases of them were attacked directly by Jiro Suzuki, one of authors, and 5 cases died after operation during hospitalization, subsequently the mortality rate was 5.6%.

Both A1 portion of the anterior carebral artery, the anterior communicating artery and aneurysm at the anterior communicating artery were observed from the point of view of the operative and angiographical findings on 68 cases.

The total number of cases with organic anomalyon the anterior portion of the circle of Willis or functional abnormality of blood circulation in A₁ portion of anterior cerebral artery were 54 cases, 79.4%. The details of these cases were as follow as, hypoplasia of unilateral A₁ portion, 37 cases, 54.4%, anomaly of anterior communicating artery 7 cases including 3 cases with a hypoplasia of unilateral A₁ portion, 10.3% and functional abnor-mality of blood circulation at A₁ portion, 13 cases, 19.1%.

These anomaly and functional abnormality on anterior portion of the circle of Willis were thought as a causal effect of the aneurysm of anterior communicating artery.

In 80 control cases that were consisted of brain tumor, epilepsia and head injury etc., unilateral Al hypoplasia were 15 cases, 18.8%, functional abnor-mality of blood circulation at A₁ portion 13 cases, 16.3% and normal 52 cases, 65%.

It was emphasized that to know the existence of the anomaly and abnormality of blood circulation at the anterior part of the circle of Willis in about 80% of anterior communicating artery aneurysms was available for the direct operation and diagnosis on the aneurysm of anterior communicating artery.