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Permanent or transient reduction of blood flow to the end-organs and to the hindbrain is the single major cause of vestibular disorders and a common cause of sensorineural hearing loss. New imaging modalities have become available which allow the recognition of focal areas of hindbrain ischemia in the prestroke stage. The correlation between focal ischemic pathology and clinical findings opens a new approach to the mapping of central pathology. In addition a detailed knowledge of the vascular anatomy of the hindbrain is indispensable for the development of new microvascular surgical techniques aimed at the restoration of sufficient blood supply.

Considerable interest has developed in otology concerning the relationship between the vascular loop and compression of the eighth nerve, producing vertigo. Several authors have described the radiographic findings relative to the anatomy of these vascular loops. Few previous articles have dealt with cases that have had surgical confirmation or repair of the defect. Our presentation concerns 27 patients who were studied by air CT cisternography of the cerebellopontine angle cistern and internal auditory canal followed by surgical repair. We postulate dampened pulsation as the reason for being able to visualize the vessels on the air study. The diversity of vessel-eighth nerve defects is illustrated. Compression of the vestibular nerve by a vascular loop should be considered one of the causes of intractable vertigo and motion intolerance and is a differential diagnosis in Meniere disease. Air CT cisternography is useful in diagnosing this condition in patients who do not respond to medical treatment.