A 62 year-old female had grade II subarachnoid hemorrhage from a giant aneurysm of the basilar artery at the right superior cerebellar artery (SCA), which was feeding an arteriovenous malformation (AVM) in the right cerebellar hemisphere. She had been suffering from right hemifacial spasm for more than 20 years. Surgery was performed through the left pterional transsylvian approach. Neck clipping was impossible. Instead, the basilar artery was clipped proximal to the SCA. The patency of the bilateral posterior communicating artery seen on preoperative angiography was assured intraoperatively. The postoperative course was complicated with left oculomotor palsy and right hemiparesis, both of which improved gradually. Right hemifacial spasm disappeared completely within one week after surgery.
Postoperative angiography showed i) an enlarged right posterior communicating artery, ii) aneurysm size decreased by 10%, iii) the right SCA decreased to one third of its preoperative size. The patient's poor heart condition made further treatment for the AVM inadvisable, and she was discharged to her home, where she could take care of herself. Seven months later, however, she fell into coma due to intracerebellar hemorrhage from the AVM and expired 10 days later. The autopsied brain revealed only a narrow infarction in the left paramedian region in the upper pons, which was due to prophylactic occlusion of the perforators. Microscopically, a decreased number of neurons and central chromatolysis were seen in the right facial nucleus. These might have been related to hemifacial spasm.
