Anterior spinal artery involved typeの破裂解離性椎骨動脈瘤の1例

A Ruptured Vertebral Artery Dissecting Aneurysm Involving the Anterior Spinal Artery:A Case Report

Ⅰ．はじめに

　くも膜下出血（subarachnoid hemorrhage：SAH）で発症した解離性椎骨動脈瘤（vertebral artery dissecting aneurysm：VADA）は発症早期，特に24時間以内に再破裂を起こす頻度が高く^6,7)，迅速かつ確実な予防治療が求められる．近年，直達手術に代わってより低侵襲な血管内治療が主たる治療戦略の1つとなりつつある．ただし，解離部に後下小脳動脈（posterior inferior cerebellar artery：PICA）を含むPICA involved typeの症例では血行再建が必要になるため，その治療選択は未だ暫定的である．VAから分岐する重要な血管として前脊髄動脈（anterior spinal artery：ASA）がよく知られており，今回われわれはASAを解離部に含む極めて稀な症例を経験した．われわれが渉猟し得る限り初めての報告であり，文献的考察を加えて報告する．

　A 50-year-old woman presented with a subarachnoid hemorrhage caused by a ruptured vertebral artery dissecting aneurysm（VADA）involving the anterior spinal artery（ASA). The ASA branched at the proximal component of the dissecting aneurysm. The rupture point was presumed to be the distal region of the dissecting aneurysm. We performed coil embolization of the distal part only in order to prevent rebleeding and preserve the ASA. The patient showed no neurological deficits. Six months after the procedure, an angiogram demonstrated occlusion of a distal portion of the right vertebral artery. However, the ASA was still patent. No rebleeding occurred, and the patient has remained neurologically symptom-free for 3 years from the treatment. ASA-involved VADAs are extremely rare. Treatment strategy is difficult because there are no options for bypass surgery and occlusion of the ASA may lead to quadriplegia unless there is collateral flow to the ASA. Although the outcome of the patient was good with partial coil embolization in this case, the treatment strategy should be carefully considered for ASA-involved VADAs.