左椎骨動脈後下小脳動脈分岐部の未破裂脳動脈瘤に対し対側後頭下開頭にてクリッピングを行った1例

Contralateral Suboccipital Approach for Clipping of an Unruptured Vertebral Artery-Posterior Inferior Cerebellar Artery Aneurysm

Ⅰ．はじめに

　椎骨動脈後下小脳動脈分岐部動脈瘤（vertebral artery-posterior inferior cerebellar artery aneurysm：VA-PICA動脈瘤）に対する手術アプローチは動脈瘤の位置，高さなどによりさまざまな方法がある．今回われわれは，VAが正中より対側へ偏位している症例の左VA-PICA動脈瘤に対し，反対側の右後頭下アプローチでクリッピングし得た症例を経験した．本例類似の症例報告は少なく，文献的考察を加えて報告する．

　Numerous approaches have been used to access aneurysms of the vertebral artery（VA)-posterior inferior cerebellar artery（PICA）complex for microsurgical clipping. Here, we report the case of a patient with an unruptured aneurysm of the left VA-PICA complex that was successfully treated using a contralateral suboccipital approach. Computed tomography angiography demonstrated a small saccular aneurysm arising from the lateral aspect of the left V4 segment just distal to the PICA origin. The aneurysm deviated to the right from the midline at the level of the jugular tubercle on angiographic evaluation, so we selected a contralateral suboccipital approach. The aneurysm was completely obliterated by neck clipping. After surgery, slight dysphagia and hoarseness appeared, but dysphagia disappeared within several days and hoarseness disappeared within 5 months. VA-PICA aneurysms can vary in their relationship to cranial nerves, brainstem, and bones of the skull base. Neurosurgeons should consider using a contralateral approach for certain aneurysms arising from a tortuous VA that has crossed the midline.