Cochlear implantation for hearing loss in vestibular schwannoma

Cochlear implantation for hearing loss in vestibular schwannoma may be a viable option to consider.  Evidence exists in the literature that vestibular schwannoma (VS) patients may benefit and use cochlear implants. The results compare well with other patients who have been implanted for single sided deafness (SSD) due to other causes.

Cochlear implantation for hearing loss in vestibular schwannoma

A computed tomography (CT) of a cochlear implantation after removal of a vestibular schwannoma.

 cochlear implant (CI) can be inserted during the primary surgical removal of the VS or at a later stage. When it is decided not to operate on a small VS, a CI can be still be placed to improve hearing. A large number of vestibular schwannomas may not grow and the presence of tumour is not necessarily a contraindication for  a CI. Some patients who have previously received radiotherapy for a VS may also benefit from a CI, although it seems that the outcome is more variable and unpredictable after radiation.

In patients with neurofibromatosis type 2 (NF2), CI may be formed before Auditory brainstem implant (ABI) becomes necessary. It may be used in one ear with an ABI on the other side in NF2. A CI does not disqualify patient for the later placement of an ABI should it become necessary.

Cochlear implantation for hearing loss in vestibular schwannoma can only be performed in those patients who retain functional cochlear nerve fibers. This is often not possible in larger tumours, whether operated or not. The same factors which determine functional outcome after CI in the rest of the population are also applicable in a patient with a VS. The duration of hearing loss is an important factor and the longer the deafness the poorer the outcome after CI. It is sometimes a better option to implant the only hearing ear with a VS than the other ear without a VS but with longstanding hearing loss.

One of the concerns that is often raised is the effect that a CI might have on future magnetic resonance imaging (MRI). MRI is required to follow up patients with VS. Certain precautions will then have to be taken to insure that the CI is not damaged and does not influence the result of the MRI. By placing the CI in a certain position adequate information can still be obtained from MRI. Always inform the radiologist before a MRI if you have a CI.