Anterior and middle skull base tumors, mainly meningiomas, are usually operated on
using a sub-frontal route with a microscope. With modern radiotherapy, the goal of skull
base surgery moves from a radical surgery with high rate of side effect to a functional
concept that aims to remove as much as possible of the tumor without compromising the
neurological status of patients. Minimally skull base surgery benefits from keyhole and
endoscopy techniques. For 3 2 decades, the development of endoscopy helps to imagine
innovative approaches for skull base tumors such as the endonasal route. Nonetheless,
CSF leak issue and the absence of direct control of the tumor margins may limit the
interest of such a route. Keyhole craniotomies have been developed with microscope but
vision issue limits their use. Combining advantages of both techniques appears therefore
natural and gave birth to intracranial assisted and more recently to fully endoscopic
keyhole surgery. For anterior or middle skull base tumors, Keyhole supraorbital
approaches can be done either by a trans-eyebrow or trans-eyelid routes. A step-by-step
description of these fully endoscopic alternative routes summarizing advantages and
drawbacks compared to others (traditional sub-frontal or more recent endonasal
approaches) is reported in this chapter by the authors.