Transcranial translabyrinthine approach to vestibular schwannomas.

Surgeons who utilize the suboccipital approach for the removal of large vestibular schwannomas, can perform a planned labyrinthectomy from within the intracranial cavity via the suboccipital exposure. This transcranial translabyrinthine approach provides one of the major advantages of the conventional transmastoid translabyrinthine approach, namely, unambiguous identification of the facial nerve as it exits the internal auditory canal, without the need for complete mastoidectomy and labyrinthectomy. The labyrinthectomy is best performed prior to the complete exposure of the internal auditory canal. The approach requires the surgeon to identify the endolymphatic sac intracranially, then drill the temporal bone and follow the vestibular aqueduct to the utricle. The lateral and superior semicircular canal ampullae, the superior vestibular nerve, Bill's bar, and the facial nerve at the lateral end of the internal auditory canal can then be identified. After testing on multiple cadaver temporal bones, this approach was used in patients with large tumours that extended far laterally in the internal auditory canal. The steps in the technique are described in detail.