Two Indices Affecting the Directions of the Sylvian Fissure Dissection in Middle Cerebral Artery Bifurcation Aneurysms
A 48-year-old woman presented with drowsy mentality due to a ruptured left MCA bifurcation aneurysm. It was difficult to expose the M1 vessel for proximal control through distal to proximal sylvian fissure dissection, so she is assigned to group I. The M1 slope gap was 1.31 mm and the M1 angles was 10.2° (). We confirmed this in the intraoperative surgical view ().