Visual evoked potentials in endoscopic and anterior skull base surgery: a review.

The anterior visual pathway can be damaged during surgery of the anterior skull base, the sellar and parasellar area, the orbit, or the paranasal sinuses. Clinical per-operative monitoring of the visual pathway is difficult and damage to the optic nerve is often only determined late. Visual evoked potentials may provide an early indication of reversible change to the visual system and various per-operative monitoring techniques have been used. These techniques show promise but at present they are too cumbersome and give results which are too variable to be reliable in per-operative monitoring.