Extradural Intracranial (Middle Fossa) Approach to the Internal Auditory Canal

N RECENT years, otologic surgeons have made an exponential advance in the surgical management and understanding of conduction deafness, largely as a result of rather highly developed microscopic techniques. Surgical procedures through the external auditory canal or mastoid do not provide a satisfactory access to the cochlea, labyrinth and their nerves. For this reason, surgical progress in the problem of perceptive loss of hearing has been limited. Classic posterior-fossa approaches limit visualization of the 7th and 8th nerves to the cerebellopontine cistern medial to the meatus of the internal auditory canal. Approximately 3 years ago we learned from a series of dissections on cadavers that a modification of the extradural (SpillerFrazier) 7 rhizotomy approach to the middle fossa provided us with a theoretically safe and surprisingly adequate exposure of the internal auditory canal and its contents. The purpose of this presentation is to describe this operation which, to date, has been performed by the authors and Dr. W. F. House:~ in 40 cases. PROCEDURE