Bilateral cochlear implants: histological findings in a pair of temporal bones

The specimens were obtained from a 63-year-old white male with acquired lues. The patient experienced sudden profound deafness on the left side 15 years prior to death, and a similar loss on the right side 3 years later. By the time of death he had carried a single induction coil in the right ear for 3 years and multiple (5) hardwire electrodes in the left ear for 8 years. A complete micro-dissection or "mini-autopsy" of the specimens was performed, and the modiolus was sectioned. Photomicrographs of the dissections will be shown. In the right ear supporting elements and numerous nerve fibers were present in the apical turn. The electrode on this side was apparently tolerated well; scala tympani was normal in shape and appearance. On the left side no nerve fibers were found in the osseous spiral lamina and there was extensive new bone formation in scala tympani. It is difficult to determine if or to what extent the implants were responsible for the severe sensorineural degeneration observed in both specimens. There was severe scarring and ossification of the posterior ampulla in both ears, in all likelihood resulting from the surgery. Some aspects of surgical techniques will be discussed in view of the histopathological findings.