Cochlear implantation in the neurofibromatosis type 2 patient: long-term follow-up

OBJECTIVE: To evaluate the long-term hearing outcomes of neurofibromatosis type 2 (NF2) patients with cochlear implants. METHODS: Retrospective analysis of cochlear implant performance in NF2 patients using open- and closed-set speech perception testing. RESULTS: Patients with NF2-associated bilateral vestibular schwannomas frequently become profoundly deaf. The aim of surgical resection should be to preserve serviceable hearing in at least one ear; however, this goal can be difficult to achieve. Frequently, tumor size or poor preoperative hearing status can require a surgical approach that leaves the patient with a profound, bilateral sensorineural hearing loss. If the cochlear nerve is preserved anatomically after vestibular schwannoma surgery, and if promontory stimulation confirms the functionality of the cochlear nerve, then cochlear implantation is an excellent option to restore hearing. We present six cochlear implant patients with NF2 who attained a significant improvement in open- and closed-set speech understanding with a mean follow-up of 7.9 (range: 5-13) years after surgery. In all but one case, the hearing results did not deteriorate over the follow-up period. CONCLUSION: Early surgical intervention for vestibular schwannomas in NF2 patients when the cochlear nerve can be spared is an important consideration to allow for possible cochlear implantation. A 6- to 8-week recovery period for the anatomically intact cochlear nerve may be necessary to obtain a positive promontory stimulation response following tumor resection and should be performed prior to cochlear implantation.