A Classification of Experimental Models of Brain Ischemia

vertebral or posterior communicating arteries. Both patients, aged 46 and 52, were believed at increased risk of infarction in the future; one patient had a recurrent ischemic episode while on anticoagulants. An occipital to posterior-inferior cerebellar artery anastomosis was performed in each patient. Neither patient was worse after surgery and clinically was unchanged. Both anastomoses were patent angiographically and by Doppler. Long-term follow-up and angiography are in progress. A discussion of the indications, technical problems, and implications of cerebral revascularization for vertebrobasilar insufficiency and infarction will be given.