For decades, the skull base has represented a virtual "no-man's land" in terms of surgical treatment. The area is extremely difficult to navigate – due to the numerous vital blood vessels and critical cranial nerves that enter and exit the base of the brain (1, 2, 3).

Perhaps the most distinguishing recent innovation in the field of Skull Base Surgery has been the introduction of Endoscopic Minimally Invasive Techniques in the treatment of complex conditions such as pituitary tumors, microvascular nerve compression syndromes, acoustic neuromas, meningiomas, and a variety of brain and skull base tumors (4, 5).

Endoscopic skull base surgery offers dramatic benefits to patients. Using extremely thin, flexible and precise endoscopic instruments, these minimally invasive approaches eliminate large craniotomies, brain retraction, scarring and nasal packing. They shorten surgery time, dramatically reduce length of stay in the hospital, and result in faster overall recovery, return to work and normal activities (6, 7).

Cranial base surgery involves treatment of the congenital, vascular, neoplastic, endocrine and traumatic lesions involving the basi cranium. This surgery is the brainchild of three specialties: Craniofacial surgery, Neurosurgery and neuro-otology and was championed by three pioneers: Tessier, Dandy and House.

Anatomically the skull base is divided into three subdivisions. The anterior skull base, the lateral skull base and the posterior or extreme lateral skull base (Fig. 1).

Anterior Skull Base

The anterior skull base is further subdivided into midline and paramedian regions. Midline lesions include congenital encephaloceles, craniofacial clefts (such as the Tessier 0-14 cleft), or tumors (such as pituitary lesions or craniopharyngiomas). Paramedian lesions include orbital tumors and locoregional extensions of paranasal sinus and head and neck tumors.

Lateral Skull Base

The lateral skull base involves lesions in the infratemporal fossa as described by Fisch. These consist of Type A, including glomus jugulare tumors, Type B, including lower clival tumors and petrous apex lesions such s cholesterol cysts. Type C and D lesions are further anterior extensions including juvenile angiofibromas and nasopharyngeal carcinomas. Lateral skull base surgery also includes transtemporal lesions (middle cranial fossa) including sphenoid wing meningiomas, neuromas of the trigeminal nerve and vascular lesions such as internal carotid artery aneurysms.

Posterior or Extreme Lateral Skull Base

Surgery of the extreme lateral skull base involves the cerebellopontine (CP) angle including acoustic neuromas, microvascular decompression of cranial nerves, meningiomas of the posterior fossa, and surgery of the craniocervical junction.