未破裂遠位部脳底動脈瘤に対するanterior temporal approachの限界とその対応

The Limits and Countermeasures of the Anterior Temporal Approach for Unruptured Upper Basilar Artery Aneurysms

Ⅰ．はじめに

　一般的に脳底動脈先端部（basilar artery top：BA top）や脳底動脈上小脳動脈分岐部（basilar artery-superior cerebellar artery：BA-SCA）の遠位部脳底動脈瘤に対する外科的治療は，transsylvian approach⁹⁾とsubtemporal approach²⁾が選択される場合が多い．しかし脳圧排の少なさや対側の後大脳動脈（posterior cerebral artery：PCA）の確認には前者が優れ，脳底動脈瘤背側の確認には後者が優れているとされ，両者は一長一短である．したがって両者の中間からapproachするanterior temporal approach（ATA）^3,7,8)は，おのおのの長所を生かし広範な術野が獲得できると考え，当院では採用している．ATAを実施する際にはapproachの限界と対応方法を理解しておく必要がある．当院における遠位部脳底動脈瘤に対するATAの実際と発展を提示し，その有用性を報告する．

　Background and Purpose：In general, upper basilar artery aneurysms are treated following the transsylvian or subtemporal approach. These approaches have both advantages and disadvantages. Therefore, we followed the anterior temporal approach that provides a wider surgical field in the retro-carotid space.

　Methods：We reviewed the clinical records of 37 patients with an upper basilar artery aneurysm operated on following the anterior temporal approach between 2002 and 2012 in our institute, and evaluated the usefulness of this approach.

　Results：In 23 cases, several additional techniques were performed. In all these cases a wide operation field was obtained in the retro-carotid space and the aneurysm was completely obliterated. The post operative adverse events were temporary oculomotor palsy in 6 cases, permanent oculomotor palsy in 3 and temporary epilepsy, aphasia due to venous infarction and asymptomatic cerebral infarction in 1 case each.

　Conclusions：The anterior temporal approach allows the additional use of several techniques and provides a wide surgical field. Therefore, we consider this approach is useful to reach and treat upper basilar artery aneurysms.