Selecting the Ear to be Implanted

Selection of the ear to be implanted is most often relatively simple. In fact, in most cases either ear is equally suitable for implantation. However, there are times when selecting the best ear to be implanted can become a complex issue.

The first step is to be sure that the both the cochlea and auditory nerve are present. This is accomplished through CT scan or MRI scans. Complete absence of these structures is extremely rare. The CT or MRI also lets the surgeon determine if the structures of the inner ear are abnormally formed, or have abnormal bone growth, and if one ear is more seriously affected than the other.

Next, we need to be certain that there is no medical reason not to implant one or the other ear. This might be based on chronic middle ear problems in one as compared to the other ear, or histories of previous surgeries. When CT Scans, MRIs or medical considerations eliminate one ear from implantation, the other is chosen.

In most instances, both ears are radiologically and medically implantable, and the decision is based on residual hearing. As seen in the algorithm below, when there is some residual hearing in both ears but one has better hearing aid function, the poorer ear is normally selected. However, when the poorer ear is long-term deafened, has no responses and has not been aided, the better ear may be chosen.

Click image for enlarged view.

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