Electrode placements for cochlear implants: a review.

Abstract

Of the variety of different sites that have been proposed and used for cochlear implants, only two are now seeing widespread use. For single-channel electrodes, it appears that a placement at the round window, or just inside it, leads to no disadvantages (and perhaps some advantages) over deeper insertions. For multichannel implants, it appears that intra-cochlear electrodes are, generally speaking, preferable to extra-cochlear ones in a variety of ways, especially as the early fears about the dangers of intra-cochlear placement now seem exaggerated. One way in which extra-cochlear approaches may play an important accessory role in multichannel intra-cochlear implants is in allowing access to the apical end of the cochlea where residual nerve survival is likely to be best. Special considerations may apply for groups of patients who until recently have been implanted relatively infrequently--adults with significant residual hearing and children.