中大脳動脈分岐部動脈りゅうに対する手術アプローチの考察 ３Ｄ‐ＤＳＡおよび術中所見の観察から

Abstract

Recent advances in neuroimaging, including 3-dimensional digital subtraction angiography (3D-DSA), enable the detailed delineation of structural characteristics of aneurysm and the parent artery. We retrospectively reviewed the operative findings and 3D-DSA images of middle cerebral artery bifurcation aneurysm (MCB-An). Morphology of MCB and An, approach to the An, and the operative view in the clipping procedure were considered in 31 MCB-Ans in 29 consecutive cases operated in 2001. In most cases, we used the distal approach, splitting the sylvian fissure from the lateral to medial direction, for clipping the MCB-An. Proximal control of the M1 was achieved in all cases. The proximal approach was performed in a case presenting with the ipsilateral internal carotid artery An. There were 2 patterns of approach angle. One is the medial trans-sylvian (m-TS) approach, in which clipping was attempted after the M1 was ensured beyond the frontal operculum. It was used in 18 cases. The other approach is the lateral trans-sylvian (l-TS) approach, which was used in 13 cases. Proximal control of the M1 was achieved between the superior and inferior trunks. The l-TS approach required an angle of approach more from the lateral and rostral side than the m-TS approach. The l-TS approach was used in cases presenting with the distal M1 running more anteroinferiorly, as compared with the m-TS approach. Morphology of the parent artery, and the relation of An and those vessels were clearly evaluated in 3D-DSA. Preoperative evaluation of 3D structures enables safe aneurysm surgery with minimum surgical procedure.