Auditory brainstem implantation in patients with neurofibromatosis type 2.
OBJECTIVE
Multichannel auditory brainstem implants (ABI) are currently indicated for patients with neurofibromatosis type II (NF2) and schwannomas involving the internal auditory canal (IAC) or cerebellopontine angle (CPA), regardless of hearing loss (HL). The implant is usually placed in the lateral recess of the fourth ventricle at the time of tumor resection to stimulate the cochlear nucleus. This study aims to review the surgical and audiologic outcomes in 18 patients implanted by our Skull Base Surgery Team from 1994 through 2003.


METHODS
A retrospective chart review of 18 patients with ABIs.


METHODS
We evaluated demographic data including age at implantation, number of tumor resections before implantation, tumor size, surgical approach, and postoperative surgical complications. The ABI auditory results at 1 year were then evaluated for number of functioning electrodes and channels, hours per day of use, nonauditory side effect profile and hearing results. Audiologic data including Monosyllable, Spondee, Trochee test (MTS) Word and Stress scores, Northwestern University Children's Perception of Speech (NU-CHIPS), and auditory sensitivity are reported.


RESULTS
No surgical complications caused by ABI implantation were revealed. A probe for lateral recess and cochlear nucleus localization was helpful in several patients. A range of auditory performance is reported, and two patients had no auditory perceptions. Electrode paddle migration occurred in two patients. Patient education and encouragement is very important to obtain maximum benefit.


CONCLUSIONS
ABIs are safe, do not increase surgical morbidity, and allow most patients to experience improved communication as well as access to environmental sounds. Nonauditory side effects can be minimized by selecting proper stimulation patterns. The ABI continues to be an emerging field for hearing rehabilitation in patients who are deafened by NF2.
Kanowitz
Seth J
SJ
Department of Otolaryngology, New York University School of Medicine, New York, NY, USA.
Shapiro
William H
WH
Golfinos
John G
JG
Cohen
Noel L
NL
Roland
J Thomas
JT
D000293:Adolescent; D000328:Adult; D001299:Audiometry; D038263:Auditory Brain Stem Implantation / Q000379:methods*; D038262:Auditory Brain Stem Implants; D003638:Deafness / Q000175:diagnosis / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D016518:Neurofibromatosis 2 / Q000175:diagnosis* / Q000601:surgery*; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012189:Retrospective Studies; D018570:Risk Assessment; D012494:Sampling Studies; D012720:Severity of Illness Index; D016896:Treatment Outcome