ABSTRACT
The middle fossa (MF) approach can be used as an extradural access route to approach the MF floor, the internal auditory canal (IAC), the posterior fossa and the petrous apex. Neurosurgeons and neurotologists considering undertaking this approach are encouraged to consider three-dimensional (3D) computerized tomographic (CT) reconstruction of the temporal bone and middle and posterior fossae prior to surgery, in order to understand the microsurgical anatomy and relations of neurovascular structures, especially where bony landmarks may be absent. The lateral end of the IAC can be identified either by first finding the GSPN as described by House or by using the SSC as advocated by Fisch. Approximately three-quarters of the circumference of the IAC at the porous acousticus are exposed. This degree of exposure is not possible at the lateral end of the IAC because of the proximity of the ampulla of the SSC and the cochlea.
