術中モニタリングの有用性と問題点 蛍光脳血管撮影と連続的ドップラー血流検査を用いた脳動脈瘤手術における穿通枝血流不全のモニタリング

Abstract

We investigated the usefulness of fluorescein cerebral angiography (FAG) and microvascular Doppler ultrasonography (MDU) for detecting the blood flow insufficiency in the perforating arteries during aneurysm surgery. FAG was performed to confirm the patency of perforating arteries located deeply in the surgical field. After aneurysm clipping, the target arteries were illuminated using a beam from the pencil-type probe with a blue light-emitting diode at its tip. After intravenous administration of 5 ml of 10% fluorescein sodium, fluorescence in the vessels was clearly observed through a microscope and recorded on videotape. The excellent image quality and spatial resolution facilitated intraoperative real-time assessment of the patency of the perforating arteries and branches such as the posterior communicating artery, anterior choroidal artery, lenticulostriate artery, recurrent artery of Heubner, hypothalamic artery or posterior thalamoperforating artery. Although MDU has generally been used in aneurysm surgery to assess the blood flow velocity before and after clipping, the complexity of keeping the MDU probe on the target vessel at the appropriate angle and degree of compression makes the detection of changes in flow velocity difficult. To overcome this problem, we continuously measured the blood flow velocity by MDU during aneurysmal clipping. The continuous MDU monitoring during aneurysm clipping enabled us to detect slight blood flow changes in real time. The findings of this study suggest that the monitoring methods introduced here are safe and reliable for detecting intraoperative blood flow insufficiency in the perforating arteries and facilitate the prevention of unexpected postoperative cerebral infarction.