gms | German Medical Science

Objective: Auditory brain stem implants (ABI) are a well-established method for hearing rehabilitation in NF2 patients. In non-tumor adult patients, the results are generally better than in tumor patients. In prelingually deaf children, cochlea implants (CI) are the method of choice for hearing rehabilitation. However, in some children CIs do not work or are not indicated because of malformations, ossifications of the cochlea or cochlear nerve aplasia. In those patients ABI may be an option, although clinical experience is still limited.

Methods: Ten children received implants with the Med-El ABI system, five male and five female children with an age range of 2–6 years. All were deaf since birth, two had previous CI without success. One had a Golden-Har syndrome with cochlear nerve aplasia, three had a cochlear malformation, a common cavity with N.8 hypoplasia, the other three had a cochlear nerve aplasia. Implantation was performed by a osteoplastic retrosigmoid approach in the prone position.

Results: The operative procedure was successful in all patients. In each case either a complete aplasia of the cochlear nerve or a severe hypoplasia was found. The internal auditory canal was extremely narrowed or not developed. Compared to adult cases, the dissection of the lateral recess of the fourth ventricle seems to be more difficult due to a adhesions and a thicker taenia. In all cases e-bera was recorded intraoperatively and the 12 channel simulation probe was successfully implanted. There were no severe surgical complications, one superficial wound infection, one CSF leak, no neurological deficit. After the first fitting, all patients developed some degree of sound awareness. Two patients were first fitted in 2/09 and 9/09. The first has achieved word and some speech understanding, points to pictures when named, the second understands 8 out of 10 words and verbally imitates her sister.

Conclusions: ABI is an accepted method for hearing rehabilitation in NF2 patients and adult non-tumor patients. There is an increasing body of evidence, that ABI is effective for restoration of hearing even in prelingually deaf children. Cases with cochlear nerve aplasia or hypoplasia or children with malformations of the cochlea where CI is doubtful or impossible are good candidates for ABI. Surgery is a safe procedure and children tolerate the device very well. It is recommended to think more often about ABI instead of accepting moderate or bad results with CI in pre-and postlingually deaf children