same as to the sellar region. however the tuberculum sellae is drilled into instead of the sella. then an opening is made that extends halfway down the sella to expose the dura, and the intercavernous sinuses is exposed. when the optic chiasm, optic nerve, and pituitary gland are visible, the pituitary gland and optic chasm are pushed apart to see the pituitary stalk. an ethmoidectomy is performed, the dura is then cut, and the tumor is removed. these types of tumors are separated into two types: prechiasmal lesions: this tumor is closest to the dura. the tumor is decompressed by the surgeon. after decompression, the tumor is removed taking care to not disrupt any optic nerve or major arteries. postchiasmal lesions: this time the pituitary stalk is in the front because the tumor is pushing it towards the area the dura was opened. removal then starts on both sides of the stalk to preserve the connection between the pituitary and the hypothalamus and above pituitary gland to protect the stalk. the tumor is carefully removed and the patient is closed up. skull base reconstruction when there is a tumor, injury, or some type of defect at the skull base whether the surgeon used an endoscopic or open surgical method, the problem still arises of providing separation of the cranial cavity and cavity between the sinuses and nose to prevent cerebrospinal fluid leakage through the opening referred to as a defect. for this procedure, there are two ways to start: with a free graft repair or with a vascularized flap repair. the free grafts use secondary material like cadaver flaps or titanium mesh to repair the skull base defects, which is very successful (95% without csf leaks) with small csf fistulas or small defects. the local or regional vascularized flaps are pieces of tissue relatively close to the surgery site that have been mostly freed up but are still attached to the original tissue. these flaps are then stretched or maneuvered onto the desired location. when technology advanced and larger defects could be fixed endoscopically, more and more failures and leaks started to occur with the free graft technique. the larger defects are associated with a wider dural removal and an exposure to high flow csf, which could be the reason for failure among the free graft. pituitary gland surgery this surgery is turned from a very serious surgery into a minimally invasive one through the nose with the use of the endoscope. for instance craniopharyngiomas (cras) are starting to be removed via this method. dr. paolo cappabianca described the perfect cra for this surgery to be a median lesion with a solid parasellar component (beside the sellar) or encasement of the main neuromuscular structures that are localized in the subchiasmatic (below the optic chiasm) and retrochiasmatic (behind the optic chiasm) regions. he also says that when these conditions are met, endoscopic endonasal surgery is a valid surgical option. for a case study on large adenomas, the doctors showed that out of 50 patients, 19 had complete tumor removal, 9 had near complete removal, and 22 had partial removal. the partial removal came from the tumors extending into more dangerous areas. they concluded that endoscopic endonasal surgery was a valid option for surgery if the patients used pharmacological therapy after surgery. another study showed that with endoscopic endonasal surgery 90% of microadenomas could be removed, and that 2/3 of normal macroadenomas could be removed if they did not go into the cavernous sinus, which means fragile blood vessel triangles would have to be dealt with so only 1/3 of those patients recovered. endoscopic endonasal approach has been shown even among young patients to be superior to traditional microscopic transsphenoidal surgery. 3-d approach vs 2-d approach the newer 3-d technique is gaining ground as the ideal way to do surgery because it gives the surgeon a better understanding of the spatial configuration of what they are seeing on a computer screen. dr. nelson oyesiku at emory university helped develop the 3-d technique. in an article he helped write, he and the other authors compared the effects of the 2-d technique vs the 3-d technique on patient outcome. it showed that the 3-d endoscopy gave the surgeon more depth of field and stereoscopic vision and that the new technique did not show any significant changes in patient outcomes during or after surgery. endoscopic techniques vs open techniques in a case study from 2013, they compared the open vs endoscopic techniques for 162 other studies that contained 5,701 patients. they only looked at four tumor types: the olfactory groove meningiomas (ogm), tuberculum sellae meningiomas (tsm), craniopharyngiomas (cra), and clival chordomas (cho). they looked at gross total resection and cerebrospinal fluid (csf) leaks, neurological death, post-operative visual function, post operative diabetes insipidus, and post-operative obesity. the study showed that there was a greater chance of csf leaks with endoscopic endonasal surgery. the visual function improved more with endoscopic surgery for tsm, cra, and cho patients. diabetes insipidus occurred more in open procedure patients. the endoscopic patients showed a higher recurrence rate. in another case study on cras, they showed similar results with the csf leaks being more of a problem in endoscopic patients. open procedure patients showed a higher rate of post operative seizures as well. both of these studies still suggest that despite the csf leaks, that the endoscopic technique is still an appropriate and suitable surgical option. otologic surgery, which is traditionally performed via an open approach using a microscope, may also be performed endoscopically, and is called endoscopic ear surgery or ees.