Hearing Response Following Internal Auditory Canal Decompression in Neurofibromatosis Type 2

Neurosurgery. 2019 Sep 1;85(3):E560-E567. doi: 10.1093/neuros/nyz057.


Background: Hearing response following an osteodural decompression of the internal auditory canal (IAC) is controversial.

Objective: To evaluate the course of auditory brainstem responses (ABRs) and the early hearing response during the first year following IAC decompression for small to medium-sized vestibular schwannomas occurring in neurofibromatosis type 2 (NF2).

Methods: Retrospective chart review of middle fossa craniotomy for IAC osteodural decompression in NF2-related vestibular schwannomas.

Results: Twelve NF2 patients were operated on from 2011 to 2016 for IAC decompression. All had NF2 according to the Manchester criteria. All had a progressive change of their ABRs documented from the diagnosis of NF2 over a mean period of 6.25 [0.36;10.9] yr. Treatment was proposed to stop hearing progression based on the speech discrimination scores (SDSs; n = 4) or for hearing maintenance (n = 8). In patients with prior hearing progression, hearing responses were observed in 3 of the 4 patients during the first year. One patient kept on progressing. In the hearing maintenance group, the SDSs remained stable. SDSs improved from 85% [20-100] to 92.5% [60-100] on average (n = 12) and from 55% [20-80] to 77.5% [50-100] in the hearing progression group (n = 4). ABRs improved in 4 patients following decompression.

Conclusion: IAC decompression allows early objective hearing responses in select patients. We suggest that the procedure should be offered to patients with hearing progression based on their SDSs and/or associated progressive increases in their wave III and V latencies on ABRs.

Keywords: Acoustic neuroma; Deafness; Hearing; Middle fossa craniotomy; Neurofibromatosis type 2; Vestibular schwannoma.

MeSH terms

  • Adolescent
  • Adult
  • Child
  • Cohort Studies
  • Decompression, Surgical / methods*
  • Ear, Inner / physiology*
  • Ear, Inner / surgery*
  • Evoked Potentials, Auditory, Brain Stem / physiology
  • Female
  • Follow-Up Studies
  • Hearing / physiology*
  • Hearing Tests / methods*
  • Humans
  • Male
  • Middle Aged
  • Neurofibromatosis 2 / diagnosis
  • Neurofibromatosis 2 / surgery*
  • Retrospective Studies