Otogenic facial paralysis. A histopathological study.

The histopathological changes of the facial canal and nerve in facial paralysis due to chronic suppurative otitis madia are described in six temporal bones. Bony destruction of the facial canal was found in its tympanic segment and in its upper mastoid part in all cases, but it was particularly notable in the labyrinthine segment as well. The pathological process, cholesteatoma or granulation tissue surrounding the exposed facial nerve was inflamed in all cases. The affected facial nerve showed degenerative and inflammatory changes throughout its tympanic segment in all cases, but its mastoid segment appeared to be relatively normal. Our findings suggest that facial paralysis occurs us chronic suppurative otitis when the inflammatory process specifically involves the facial nerve trunk.