Cerebrovascular occlusive disease has been and continues to be a leading cause of death and disability throughout the world. In the United States there are about 400,000 new strokes each year. Some 90% of strokes are a result of vascular occlusion of the extracranial circulation. Surgical treatment of occlusive vascular diseases, principally carotid endarterectomy, has become an accepted method of treatment of a large number of patients. However, only about 70% of patients with cerebrovascular disease have surgically accessible lesions in the extracranial circulation. The remaining 30% are a result of intracranial occlusive disease which cannot at present be treated by carotid endarterectomy
