Audiometric Outcomes of Auditory Brainstem Implantation During Vestibular Schwannoma Resection in NF2 Patients

Background: Many patients with neurofibromatosis type II (NF2) suffer from sensorineural hearing loss, and associated cochlear nerve compromise in NF2 patients makes auditory brainstem implant (ABI) an attractive treatment option. The long-term outcomes and benefits of the device are still being explored. Methods: A retrospective review was conducted for 11 ABI recipients at a single institution tertiary center between November 2017 to August 2022. Patients diagnosed with NF2 undergoing resection for concurrent vestibular schwannoma (VS) were included. Pre and post audiometric assessments were reviewed. Evaluation included pure-tone audiometry and speech testing. Results: Our cohort included 11 patients with a median age of 34 years old. All patients underwent a translabyrinthine approach for implant placement with concurrent VS resection. Average tumor size of VS was 2.87 cm. Pre-operatively, 8 patients had pure tone averages (PTA) with no response at 110 dB, 2 were within mild-moderate hearing loss (25-45 dB), and one patient had a PTA of profound loss (92 dB). Post-operatively, 9 (81%) patients had improvement in PTA. In total, 7 patients reported mild side effects upon ABI activation which included dizziness (n=2), tinnitus (n=1), and abdominal and lower extremity tingling sensation (n=3). Of the 7 patients with ESP scores, 5 had a score >75%, indicating the auditory ability to detect pattern perception upon auditory stimulation through the ABI alone. Conclusions: Nine of 11 patients derived benefits from ABI placement. These findings demonstrate that ABI placement during concurrent VS resection can provide a significant hearing benefit for NF2 patients.