Abstract
An auditory brainstem implant (ABI) is a surgically implanted central neural auditory
prosthesis for the treatment of profound sensorineural hearing loss in children and
adults who are not cochlear implant candidates due to a lack of anatomically intact
cochlear nerves or implantable cochleae. The device consists of a multielectrode surface
array which is placed within the lateral recess of the fourth ventricle along the
brainstem and directly stimulates the cochlear nucleus, thereby bypassing the peripheral
auditory system. In the United States, candidacy criteria for ABI include deaf patients
with neurofibromatosis type 2 (NF2) who are 12 years or older undergoing first- or
second-side vestibular schwannoma resection. In recent years, several non-NF2 indications
for ABI have been explored, including bilateral cochlear nerve avulsion from trauma,
complete ossification of the cochlea due to meningitis, or a severe cochlear malformation
not amenable to cochlear implantation. In addition, growing experience with ABI in
infants and children has been documented with encouraging outcomes. While cochlear
implantation generally remains the first-line option for hearing rehabilitation in
NF2 patients with stable tumors or post hearing preservation surgery where hearing
is lost but a cochlear nerve remains accessible for stimulation, an ABI is the next
alternative in cases where the cochlear nerve is absent and/or if the cochlea cannot
be implanted. Herein, we review ABI device design, clinical evaluation, indications,
operative technique, and outcomes as it relates to lateral skull base pathology.
Keywords
auditory brainstem implant - hearing loss - auditory prosthesis - electric stimulation
- auditory nerve - neurofibromatosis type 2
