11. 椎骨脳底動脈循環不全の原点と歴史的変遷

抄録

　Vertebro-basilar insufficiency (VBI) is a brief episode of reversible neurological deficits caused by transient ischemia of the brainstem due to impairment of the vertebro-basilar arterial system.

　VBI was introduced initially as “syndrome of intermittent insufficiency of vertebro-basilar arterial system” and its pathophysiology was recognized to be vascular dysfunction of the brainstem in the early 20th century. Later, in the 1950's, VBI was proposed to be one clinical entity characterized by various combinations of recurring neurologic symptoms and signs involving vertigo, disequilibrium, double vision, visual hallucination, gait ataxia, face and limb numbness, weakness, dysarthria and dysphagia. The common causes of VBI were considered as atherosclerosis, which can block the posterior circulation supplying the brainstem, embolism arising from the heart and the proximal vertebral and basilar arteries due to arrhythmia, and hemodynamic disorder related to changes of the blood pressure, as well as mechanical obstruction of the vertebral artery induced by vertebral spicules.

　Various modalities such as vertebral angiography, Doppler ultrasonography, MRI and MRA are now available as useful tools for identifying the vascular structural lesions. Diffusion-weighted MRI may be useful to identify early ischemic lesions. However, it remained no major changed fundamentally in the present for diagnosis techniques depending on the history of the attacks, because it is still difficult to clinically determine the precise circulation disorder within the vertebro-basilar arterial system. Further discussions are needed to consolidate the diagnostic criteria, including the concept and pathogenesis of VBI with vertigo, in the future.