Fig. 2

Major steps during the endoscopic mini-pterional keyhole approach clipping of a middle cerebral artery bifurcation aneurysm. A Three-dimensional angiography showed the middle cerebral artery bifurcation aneurysm. B Surgical skin incision. C The sylvian fissure and carotid cistern were opened to expose the internal carotid artery and its bifurcation. D Aneurysm was then dissected. E–G The aneurysm was clipped and visualized with the Lazic aneurysm clip (blue five-pointed star). H Postoperative digital subtraction angiography showed a well-clipped aneurysm with no residual filling. I The extent of the bone window under the endoscopic view. J, K Postoperative CT scan indicated the extent of the craniotomy (green circle)