頚椎インストゥルメンテーション手術における3次元CT血管造影法を用いた椎骨動脈-後交通動脈の術前評価

Preoperative Evaluation of Vertebral and Posterior Communicating Arteries Using 3-dimensional CT Angiography before Cervical Posterior Instrumentation Surgery

　3次元CT血管造影を用いて，頚椎後方インストゥルメンテーション術前に45例の椎骨動脈(VA)走行および後交通動脈(PCOM)開存状態の評価を行った．18％の症例でVA径に1.5mm以上の左右差を認め，骨内外でのVA走行異常は18％で認められた．PCOMは42％の症例で両側ともに開存しておらず，そのような症例にVAの左右差を認めた場合(約7％)，対側のVA損傷には特に注意を要する．

　We preoperatively examined 45 patients to investigate the frequency of an anomalous vertebral artery (VA) and the presence of a posterior communicating artery (PCOM) using 3-dimensional CT angiography (3D-CTA). Asymmetry of the VAs was detected in eight patients (18%). Anomalous VAs in the intra- or extraosseous region, including a high-riding VA, persistent 1st intersegmental artery, and ponticulus posticus, were found in a total of 8 patients (18%). Nineteen patients (42%) did not have a PCOM on either side. When a VA, especially the VA on the dominant side, is injured during cervical instrumentation, catastrophic vascular complications occur in approximately 7% of patients who have asymmetrical VAs without collateral circulation. Preoperative 3D-CTA provides information on anomalous VAs and collateral circulation that is crucial to preventing vascular complications.