Surgery of the skull base.

Tumors involving the base of the skull are often occult and may become quite large before detection is possible. Symptomology varies depending upon the nature of the tumor and its placement. These neoplasms have frequently been considered inoperable simply because of their location, but in recent years microsurgical technique and high speed air drills have allowed the modern temporal bone surgeon to gain improved access to the skull base. A wide variety of surgical approaches to tumors in this area have been described in the past 20 years: translabyrinthine, middle fossa, transcochlear, retrolabyrinthine, retrosigmoid, transpalatal-transclival, and through the jugular bulb. The purpose of this paper is to review the indications, complications, and results of each of these procedures in relation to specific tumors involving the skull base. Case reports illustrate the diagnosis and surgical management of a variety of unusual neoplasms, including an extradural meningioma of the temporal bone and clivus, a low grade squamous cell carcinoma on the tegmen in a radical cavity, a large primary cholesteatoma, an osteoblastoma of the temporal and occipital bones, an XIth nerve neuroma in the jugular bulb area, and an osseous hemangioma involving the facial nerve at the geniculate ganglion.