Surgical treatment of middle cerebral artery aneurysms.

Middle cerebral artery (MCA) aneurysms account for approximately 20% of aneurysmal subarachnoid hemorrhage (SAH). An understanding of MCA anatomy and variations is the key to successful treatment of MCA aneurysms, which may occur on the M1 segment, at the division of the main trunk or on distal branches. Patients may present with SAH, mass effect, epilepsy, or ischemia. MCA aneurysms associated with large temporal hematomas may be approached through the superior temporal gyrus. Other aneurysms are best approached with a medial or lateral transSylvian approach.