The transcochlear approach to the skull base.

A new approach to tumors of the skull base is described. This approach is accomplished by forward extension of the translabyrinthine opening into the cerebellopontine angle. The facial nerve is mobilized in the temporal bone from the stylomastoid foramen to its entrance into the internal auditory canal. Having removed the barrier of the facial nerve, additional bone removal can be carried forward to the internal carotid artery, which now becomes the forward limit for temporal bone resection. The access attained through this exposure allows removal of tumors arising from the petrous tip, as well as tumors arising directly from the clivus. We provide the case histories of four patients in whom this approach was successfully used in removal of skull base tumors.