Use of STA-MCA anastomosis for clipping of giant middle cerebral artery aneurysm--case report.

A 50-year-old female developed subarachnoid hemorrhage due to rupture of a giant aneurysm in the left middle cerebral artery (MCA). One month later, direct surgery was performed on the aneurysm. The superficial temporal artery was anastomosed to the cortical artery of the parietal MCA segment. The MCA was exposed and trapped for 40 minutes during barbiturate infusion, with electroencephalographic and somatosensory evoked potential monitoring. During MCA trapping, the aneurysm was collapsed by dome puncture and obliterated by neck clipping. After surgery, she had only mild amnestic aphasia and an infarct in the medial temporal lobe demonstrated by computed tomography. However, cerebral angiography disclosed complete occlusion of the MCA by the displaced aneurysm clip, and perfusion of the distal MCA segments through the anastomosis. The initial bypass procedure prevented a disastrous outcome in this patient and is recommended for direct surgery on MCA aneurysms.