Extracranial-Intracranial Vascular Shunt Procedures

Cerebrovascular occlusive disease has been and continues to be a leading cause of death and disability throughout the world. In the United States there a re about 400,000 new strokes each year. 1 Some 90% of strokes are a result of vascular occlusion of the extracranial circulation.2 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 accessi ble lesions in the extracranial circulation . The remaining 30% are a result of intracranial occlusive disease which cannot at present be treated by carotid endarterectomy. Endarterectomies or embolectomies or both have been a ttempted intracranially but have carried high morbidity a nd morta lity rates. Middle cerebral artery embolectomy, for example, has been successfully performed technically, but the results have been poor. Presently, bypass procedures seem to carry a smaller mortality and morbidity rate and a better clinical result. Austin has estimated that there are about 12,000 patients with inoperable lesions by conventiqnal vascular techniques who might be candidates for a bypass procedure of an obstructed or stenosed intracranial vessel. 3 The first intracerebral bypass procedure was performed in 1944 by Henschen.' He transplanted a pedicle of temporalis muscle over the surface of the brain . The pa tient apparently improved, but this by-