前床突起下前外側壁に生じた内頸動脈瘤に対する直達手術

Direct Surgery for Paraclinoid Aneurysm Arising from the Anterolateral Wall of the Internal Carotid Artery

Ⅰ．は じ め に

　傍前床突起部動脈瘤（paraclinoid aneurysm；PA）とは硬膜輪から後交通動脈分岐部までの内頸動脈より発生したものと定義されることが多く，さらに近年，発育方向や眼動脈，上下垂体動脈との位置関係等より種々の分類^1,9,12)がなされている．このうち内頸動脈前外側壁より生じた動脈瘤は稀である．今回われわれは，分岐血管を認めない内頸動脈前外側部より生じた未破裂PA 5例を経験したので，手術手技について若干の文献的考察を加え報告する．

The internal carotid aneurysm (ICA) arising from the paraclinoid region is associated with the origins of the superior hypophyseal artery and the ophthalmic artery. Recently,other aneurysms which can arise in this region without imvolvement of the arterial branches has been reported. Among those aneurysms,there are very rare type of aneurysms located on the anterolateral aspect of the internal carotid artery.

　In this report,we described our experience with direct surgery for five cases of the unruptuted paraclinoid aneurysm arising from the anterolateral aspect of the ICA.

　Firstly,the common carotid artery was exposed to carry out proximal flow control. We used the pterional approach. The anterior clinoid process was deleted after having confirmed aneurysm and the dural ring was incised. Extreme care had to be taken during this step. All patients underwent successful neck clipping.

　In recent two cases we employed the neuroendoscope (EndoArmTM) to observe the unrecognized area of surgical microscope and untrasonic bone curette (SONOPETTM) to perform the safe removal of the anterior clinoid process. This procedure is very useful for carring out the neck clipping for aneurysms which are located on the anterolateral aspect of the internal carotid artery.