Bilateral Auditory Brainstem Implants in Patients With Neurofibromatosis 2

To discuss indications for bilateral auditory brainstem implants (ABIs), compare audiometric outcomes of unilateral vs bilateral ABIs, and determine if patients have improved outcomes with addition of a second-side implant.

Retrospective review of 24 patients with neurofibromatosis 2 (NF2) who underwent sequential placement of ABIs from 1989 to 2019.

Tertiary referral center.

Charts were reviewed for indication for second-side surgery, use of implants, and audiometric outcomes. Implants placed in the past 30 years were included in the study. Northwestern University Children's Perception of Speech (NU-CHIPS) and/or City University of New York (CUNY) sentence scores were compared in unilateral and bilateral conditions.

Indications for a second-side implant included first-side implants with severe nonauditory symptoms (11), marginal audiometric results (9), outdated technology (2), or deterioration of first side (2). Seven patients are bilateral users and 1 patient discontinued bilateral use after a year due to no significant improvement over unilateral use. One patient with initial bilateral use was lost to follow-up. Thirteen patients are unilateral users due to nonaudiometric side effects or poor audiometric outcomes with the first side. Two patients are complete nonusers. Seventy-five percent had improved audiometric outcomes after the second-side implant, and 20% had stable findings.

Second-side ABIs should be consider in patients with poor performance from a first-side implant. Most patients demonstrate subjective improvement with the second ABI. More research is needed for better objective assessments of improvements.