ネッククリッピング不可能な椎骨動脈瘤に対する治療的一側椎骨動脈閉塞術—特に術後の脳幹虚血について

Therapeutic Occlusion of Unilateral Vertebral Artery for Unclippable Aneurysms; Special reference to postoperative brainstem ischemia

I．はじめに

　ネッククリッピング不可能の椎骨動脈瘤に対し，prox—imal occlusionやtrappingにより，一側の椎骨動脈（以下VA）が遮断されても，健側VAが患側と同等またはそれ以上の太さであれば問題はないとされている．しかし，この条件を満たし術後無症状であっても，一定期間を経て脳幹虚血の症状が出現することがある．自験例をもとに，一側VA閉塞後の脳幹虚血発生の予防方法について検討する．

Seven cases of unclippable vertebral artery aneurysms (3 dissecting, 1 fusiform, 2 saccular and 1 giant) are reported. Five of these had subarachnoid hemorrhage, one showed mass effect and the other was found incidentally.

Trapping of the involved portion of the vertebral artery was performed in 4 cases, proximal clip occlu-sion in 2 and proximal balloon occlusion in 1. There were no operative deaths and no rebleeding, but brain-stem ischemia developed in 4 cases, two being transient and two permanent. The ischemic complications were possibly due to; (a) hypoperfusion in the transient cases and (b) thromboenbolism, from the partially thrombosed giant aneurysm or thrombosis of the cul-de-sac vertebral artery, in the permanent ones. Preoperative temporary vertebral artery occlusion with an inflatable balloon or postoperative anticoagu-lant therapy should be considered in the management protocol.