Fig. 2

A: modified Intradural anterior clinoidectomy. Each stage is marked with a colored star. Blue star: anterior clinoid process residue. B: proximal control of clinoidal internal carotid artery, Green star: optic nerve, Purple star: aneurysm neck: tandem clip application. D: intraoperative fluorescein angiography is a crucial step in OAA microsurgery. The yellow star shows the parent vessel flow