[Surgical Setup and Perioperative Management for Endoscopic Transsphenoidal Surgery]

Endoscopic transsphenoidal surgery has been the most commonly performed neuroendoscopic procedure in Japan since its reimbursement category was introduced in 2012. Although the surgical technique is now largely standardized, perioperative management and operating room setup still vary among institutions. At our center, patients are positioned in a semi-Fowler's posture with the head elevated to reduce venous bleeding from the cavernous sinus, while carefully monitoring the risk of venous air embolism. A slight vertex-up angle facilitates a natural instrument trajectory and is adjusted according to lesion location. Surgery is performed using a four-hand technique, with the assistant controlling the endoscope and coordinating movements with the surgeon, adapting to anatomical constraints and the use of straight or angled endoscopes. We also describe our approach to perioperative glucocorticoid supplementation, postoperative endocrine management for pituitary disorders, and the prevention and treatment of delayed postoperative hyponatremia. Collaboration with otolaryngologists is preferred for postoperative nasal care. These strategies aim to enhance surgical safety, infection control, endocrine stability, and patient comfort while supporting continued advances in endoscopic skull base surgery.