Siting the receiver-stimulator of the CI-24M model of the Cochlear Limited multiple-channel cochlear implant and fixation of its electrode array

Abstract

The correct siting of the cochlear implant receiver-stimulator package is important. The package should not obtrude significantly above the surface of bone, and should be so that blows to the head do not in damage to the package, skull or brain.

The cochlear implant electrode array must be fixed at a site close to the cochlea, so that the electrode will not slide out, or be subject to differential movement with growth changes. Fixation, with Dacron® mesh, platinum-iridium ties, or clips, has been in the region of the posterior root of the zygoma and the floor of the antrum. Our research studies demonstrate that a specially-designed collar around the array can be placed through the cochleostomy and provide the necessary locking to prevent retraction of the array. It has a ceramic surround to encourage union with neighbouring bone, and stress relief to reduce wire fracture at the point where the array leaves the cochlea.