Skull base surgery may be done to remove both non-cancerous and cancerous growths, and abnormalities on the underside of the brain, the skull base or the top few vertebrae of the spinal column. Because this is a difficult area to reach, skull base surgery is most often performed as a minimally invasive endoscopic procedure through the nose. Conditions such as pituitary tumors, meningiomas, chordomas, cerebrospinal fluid fistulas, cysts and growths caused by infections are treated in this manner.