Histopathology of the facial nerve after longitudinal temporal bone fracture.

The temporal bone histopathology in a patient who suffered repeated head trauma and a longitudinal temporal bone fracture shows unusual features associated with the facial nerve. In the distal meatal segment, a type of traumatic neuroma was found with disorganized nerve bundles and distinct areas of Schwann's cell proliferation but lacking fibrosis. Periosteal new bone formation in the labyrinthine segment narrows the fallopian canal and protrudes into the nerve, which completely fills the canal. The tympanic and mastoid segments of the nerve show severe degeneration of nerve fibers and an increase in connective tissue between fascicles. An attempted facial nerve decompression did not reach the area of primary pathology in the labyrinthine and meatal segments of the nerve, which could have been exposed by the transtemporal supralabyrinthine approach.