Surgical anatomy for infralabyrinthine approach to the internal auditory canal.

Surgical anatomy for infralabyrinthine approach to the internal auditory canal was evaluated using human temporal bone in order to understand advantages and disadvantages of this approach. The procedure is extracranial without any damage of labyrinth. Lateral exposure of the internal auditory canal allows for easy separation of the cochlear and vestibular nerves. There are some potential problems of little importance stemming from anatomical variations, such as high jugular bulb, forward positioned sigmoid sinus and poor pneumatization of the infralabyrinthine space. This approach offers access to the eighth cranial nerve with minimal risk and morbidity.