Human vestibular epithelia: prospects for future study

The lateral ampullae of thirteen patients, removed during translabyrinthine surgery for various disorders, have been examined with light and electron microscopy. Correlation of results of vestibular function tests with changes of histology and ultrastructure have been attempted. Light and electron microscopy revealed the same features that other investigators have reported as pathologic changes in the sensory epithelium and associated subepithelial structures. The occurrence of these features did not correlate with the vestibular function tests, indicating that these features, in our tissue samples, were handling and preparation artifacts. Two observations made in a specimen from a patient with Meniere's disease were difficult to ascribe to handling or preparation artifact. One was the presence of densely stained granular inclusions in the basal portion of the sensory epithelium. The location and contents of these inclusions as seen in the electron microscopy indicated they were hypertrophied degenerating nerve terminals. Similar inclusions were also seen in the axoplasm of myelinated nerve fibers in the sensory subepithelial connective tissue. The other observation believed to be relevant to the symptoms of Meniere's disease, was the presence of widened tight junctions between adjoining sensory and supporting epithelial cells. The attempt at correlation of histologic and ultrastructural changes of ampullae with vestibular function has made possible some differentiation between pathology and artifact. The significance of the ultrastructural observations is discussed.