Into and out of the cochlea: A re-implantation saga

Introduction: In patients with normal inner ear architecture at imaging and who received a prior cochlear implant (CI) without difficulty, the expectation is that replacing a failed CI should be straightforward. Here, we present a patient in whom an unusual complication (to our knowledge, not reported) was encountered. Methods: Review of audiological and medical and surgical records and imaging data. Results: Re-implantation went well except no electrically elicited compound action potential could be elicited via any electrode. The replacement CI did not provide any auditory perception. CT showed the electrode array to enter the cochlea with three electrodes, but all other electrodes extended toward the Eustachian tube. Subsequent re-implantation into the scala vestibuli yielded excellent performance with the CI. Conclusion: Mechanical forces, such as from a CI array, can erode the hardest bone over time. This possibility should be a consideration in patients who are undergoing CI device replacement.