Background: Endoscopic transsphenoidal surgery is a relatively novel technique with a long learning curve: it is used to resect tumors that grow in the sella. which is located at the center of the skull base. immediately below the optic nerves and brain that are wrapped by the arachnoid. containing the cerebrospinal fluid (CSF). https://www.unitedssports.shop/product-category/electronics-heart-rate-monitors/