上小脳動脈末梢部破裂動脈瘤の1例—手術アプローチについての考察

A Ruptured Peripheral, Superior Cerebellar Artery Aneurysm:A case report and a review of the literature as to surgical approaches

I．はじめに

　上小脳動脈末梢部破裂動脈瘤の発生頻度は0.2％^19）と極めてまれで，現在まで20数例の報告をみるにすぎない^{1-3,5,7-9,11-18,20）}．最近，われわれは上小脳動脈末梢部の破裂性動脈瘤を経験したので報告すると共に，その手術アプローチについて考察する．

The authors described the case of a normotensive 40-year-old female with severe headache and vomiting. Neurological findings on admission to our hospital re-vealed no deficits, but plain CT findings indicated sub-arachnoid hemorrhage in the ambient, supracerebellar, quadrigeminal, and right lateral pontine cisterns. Left vertebral angiograms made through a transfemoral catheter revealed a saccular aneurysm (6×4mm) aris-ing from the medial hemispheric branch of the right su-perior cerebellar artery (SCA). On the 34th day after onset of her symptoms, the aneurysm was successfully clipped by using an infratentorial supracerebellar approach. She was discharged with no deficits. Based on our experience and a review of the litera-ture, a peripheral SCA aneurysm is best clipped by us-ing one of the following surgical approaches:(1) a subtemporal transtentorial approach for an aneurysmarising from the anterior or lateral pontomesencephalic segment,(2) a subtemporal or occipital transtentorial approach for an aneurysm arising from the cerebel-lomesencephalic segment or the proximal cortical branch, or (3) an infratentorial supracerebellar appro-ach for an aneurysm arising from the distal cortical branch.