Cochlear implants for congenital deformities.

There have been few accounts of multi-channel cochlear implants in patients with congenital structural deformities of the inner ear which are associated with severe and sometimes progressive deafness. These malformations can now be recognized easily on 2 plane thin section high resolution CT studies which are mandatory for the pre-implantation assessment. However, no attempt seems to have been made to describe which of these malformations would be suitable for an implant or for which would this procedure be contra-indicated. True Mondini deformity of both the cochlea and dilated vestibular aqueduct type would appear suitable for a multi channel implant, but this type of implant should not be used for a primitive otocyst, severe labyrinthine dysplasia or the characteristic X-linked deformity.