Vertebrobasilar angulation and its association with sudden sensorineural hearing loss.

The pathogenesis of sudden sensorineural hearing loss (SSNHL) is unclear, though some researchers postulate the major mechanism of onset to be via circulatory disturbance or cochlear inflammation. SSNHL can represent the sole manifestation of anterior inferior cerebellar artery infarction, and patients with a SSNHL may have higher than normal risk of future stoke. According to a vascular remodeling theory, vertebral arteries (VAs) are typically asymmetric with the basilar artery (BA) gradually curving in the opposite direction of the larger VA. Decreased wall shear stress on the inner surface of the curvature (weaker side of the vertebral artery) gives rise to an atherothrombogenic environment. It is hypothesized that angulation of the BA could contribute to the decline of anterior inferior cerebellar artery (AICA) flow or to the development of atheroma formation in the AICA orifice. Vertebrobasilar junction angulation could represent a simple and useful marker of SSNHL caused by a vascular compromise of the cochlea.