Auditory Brainstem Implants in NF2 Patients: Results and Review of the Literature

Objective: Neurofibromatosis Type 2 (NF2) patients have multiple central nervous system tumors and, specifically, bilateral vestibular schwannomas (VSs) causing bilateral deafness. If the cochlear nerve is not preserved during tumor removal, the only hearing rehabilitation in these patients could be via an auditory brainstem implant (ABI). Study Design: Retrospective case study and literature review. Setting: Tertiary referral cranial base center. Patients: In 24 NF2 patients, 25 ABIs were placed in the lateral recess of the fourth ventricle after VS surgery via a translabyrinthine approach. Results: In this series, a large range of results are observed: from open speech and use of the telephone to no ABI use, because of the poor sound identification ability. Of the 24 patients, 19 use their ABI on a daily basis, 4 are nonusers, and 1 died of NF2 progression. A multivariate analysis did not reveal a good predictor for ABI outcome. In literature, the results of ABI in NF2 are difficult to compare, and the overall outcome was poor compared with cochlear implantation results. Conclusion: Auditory brainstem implantation in NF2 patients directly after tumor removal is a safe procedure and the best means of hearing rehabilitation if the cochlear nerve is not preserved. The results in NF2 cases in the literature and these series are poor compared with cochlear implantation. If a cochlear implant is possible, it has the preference over an ABI, also in NF2. Nevertheless, the majority of the patients have benefit of the ABI during daily life particularly in combination with lip reading.