Temporal bone pathology of a patient with cochlear implant.

A 66-year-old man with profound total deafness received a 22-channel cochlear implant. After surgery, his hearing improved and the postoperative course was uneventful except transient vertigo. The patient died of lung cancer after 2.5 years. Twelve hours after death, the temporal bone was harvested for histological and electron microscopic examination. The mastoid air cells were preserved, although a few mucosal folds were present. The Dacron mesh tie had largely been absorbed, but part remained embedded in fibrous tissue. No inflammation was noted in the tympanic cavity or the round window through which the electrodes were inserted. In the cochlea, the scala tympani was filled with fibrous tissue at the site of electrode insertion. The scala media had collapsed, while the organ of Corti and stria vascularis showed degeneration. Osseous spiral bundles and spiral ganglion cells were noted, though reduced in number.