Internal auditory artery infarction - Clinicopathologic correlation

Objective: To study the pathophysiology of labyrinthine infarction. Backgro und. The syndrome of sudden onset vertigo hearing loss is commonly attribut ed to inner ear vascular disease, yet histologic studies of isolated labyri nthine infarction in humans have been rare and have not included a complete examination of the vertebrobasilar vascular system. Methods: Temporal bone s, brainstem, cerebellum, and the supplying blood vessels were subjected to gross and microscopic postmortem examinations in a 92-year-old woman who h ad a sudden onset of vertigo and hearing loss in the right ear 7 years befo re death. Results: There were prominent atherosclerotic changes at the vert ebrobasilar junction, but the internal auditory artery and its branches wer e patent on both sides. Histologic studies showed degenerative changes in t he cochlea and vestibular labyrinth on the right. The posterior canal ampul la and saccular macule were relatively preserved showing partial areas of i ntact sensory epithelium with underlying nerve fibers. The right vestibuloc ochlear nerve showed a fibrotic scar and multiple patchy areas of degenerat ion. These findings are most consistent with a transient period of reduced perfusion of the internal auditory artery. Conclusion: The partial sparing of the inferior vestibular labyrinth may indicate a decreased vulnerability to ischemia because of its better collateral blood supply.