Histopathological features of a cochlear implant and otogenic meningitis in Mondini dysplasia.

The temporal bones of a 6-year-old boy with a cochlear implant for profound hearing loss associated with Mondini dysplasia were studied histopathologically. Despite having severe Mondini dysplasia, he was able to detect sound with the implant. On histological examination of the temporal bone, he had more than 10000 spiral ganglion cells. Histopathological changes in the inner ear associated with the cochlear implant were minimal. Patients with severe Mondini dysplasia and profound hearing loss may, therefore, benefit from cochlear implantation. In the contralateral ear, the patient had suppurative labyrinthitis and meningitis associated with chronic otitis media. Histopathological evidence of inflammatory necrosis of the round window membrane was consistent with suppurative labyrinthitis secondary to otitis media.