[[Oskar Hirsch]] described the fully extracranial endonasal transethmoid transsphenoidal approach in [[1909]]. He was the first to describe the surgical entrance to the sella using this exclusively unilateral [[endonasal]] route, which he demonstrated on a cadaver. He reports performing this procedure on a live patient in April, [[1910]], under [[local anesthesia]] in stages over 5 weeks. For better exposure, Hirsch consolidated his method with Killian's submucosal window resection of the posterior [[nasal septum]] allowing for bilateral access to the sphenoid sinus and sella, and completed a single-stage procedure on a patient in June 1910. Oskar Hirsch was the first to describe and perform a stepwise surgical approach to the [[sella]] using an exclusively extracranial, endonasal, [[transethmoidal]], and transsphenoidal approach. He built upon his mentor Markus Hajek's approaches to the posterior ethmoid cells and [[sphenoid sinus]] ((Ben-Shlomo N, Mudry A, Naples J, Walsh J, Smith TR, Laws ER, Corrales CE. Hajek and Hirsch: Otolaryngology Pioneers of Endonasal Transsphenoidal Pituitary Surgery. Laryngoscope. 2023 Apr;133(4):807-813. doi: 10.1002/lary.30496. Epub 2022 Nov 24. PMID: 36420787; PMCID: PMC10023270.)).