Extracranial-intracranial bypass surgery in cerebrovascular diseases.

Since the report from the International Study on extracranial-intracranial bypass was presented in 1985, an abrupt stop to almost all bypass surgery was introduced. The clear goals of the bypass study to reduce repeated strokes based on extracranial-intracranial bypass could not be documented. This review emphasizes the drawbacks of this previous study and why its conclusions were too sweeping, including statements that the study could not validate. The present status on cerebral hemodynamics and possible augmentations of reduced cerebral vascular reserve using extracranial-intracranial bypass are given. It is concluded that in hemodynamic proven cases extracranial-intracranial bypass may definitely benefit the patients. This group of patients, among all stroke victims in the International Study, could not be deducted due to the study design. The high frequency of repeated serious strokes occurring among patients with hemodynamic insufficiency and its prevention by bypass surgery is documented. The right operation was carried out among a large group of "wrong" patients. The prevention of repeated strokes that an extracranial-intracranial bypass allows us today, indicates that this operative method should also be possibly applied in the Kingdom under well defined hemodynamic circumstances.