ABSTRACT
A 47-year-old man presented with a superior hypophyseal artery aneurysm and an ipsilateral posterior communicating artery aneurysm. Both lesions were successfully clipped without removal of the anterior clinoid process or retraction of the optic nerve by using endoscopic guidance. The endoscope was introduced into the prechiasmatic cistern and provided a clear visual field around the aneurysm that could not be seen via the operating microscope. The endoscope was useful in the identification of the medially projecting lesion and the small perforating branches of the ophthalmic segment of the internal carotid artery. A fenestrated clip could be introduced around the neck of the aneurysm and placed in the best position under endoscopic guidance. Endoscopy-assisted clipping is potentially a very useful procedure for aneurysm surgery.