Abstract
Middle cerebral artery aneurysms arise mostly at the bifurcation of the horizontal part (Ml) of the middle cerebral artery. In many cases, proper dissection of the sylvian fissure allows observation of the whole aneurismal structure, so that neck clipping is not so difficult. However, care should be taken to avoid postoperative morbidity in particular cases including a short Ml, broad neck, and atherosclerosis of the neck/body. Surgical techniques for those cases are described in detail.