Principles of Pituitary Surgery.

Since the description of a transnasal approach for treatment of pituitary tumors, transsphenoidal surgery has undergone continuous development. Hirsch developed a lateral endonasal approach before simplifying it to a transseptal approach. Cushing approached pituitary tumors using a transsphenoidal approach but transitioned to the transcranial route. Transsphenoidal surgery was not "rediscovered" until Hardy introduced the surgical microscope. An endoscopic transsphenoidal approach for pituitary tumors has been reported and further advanced. We describe the principles of pituitary surgery including the key elements of surgical decision making and discuss the technical nuances distinguishing the endoscopic from the microscopic approach.