In 1910, Oskar Hirsh, an otolaryngologist, introduced a transseptal, transsphenoidal approach to the pituitary gland 1) an operation which is still in use today. Cushing performed his first pituitary operation in 1909 2) using Schloffer's method but then rapidly adopted Hirsh's approach adding a sublabial incision and a headlamp to improve visualization of the sella. Using this approach he performed 231 operations with a 5.6% mortality rate 3) 4).
Hirsch continued to perform transphenoidal hypophysectomy and by 1937 had performed the operation on 277 patients with a mortality rate of 5.4% 5). After being displaced from Austria by the Nazis shortly thereafter, he emigrated to the US and continued to operate at Massachusetts General Hospital in collaboration with a neurosurgeon, Hannibal Hamlin. The other surgeon who kept the technique alive was Norman Dott, a British neurosurgeon who learned the approach in 1923 from Cushing and by 1956 had performed 80 procedures with no deaths 6).
The modern advent of the transsphenoidal approach as the preferred approach to the pituitary began in 1956 when a French neurosurgeon, Gerard Guiot, learned the technique from Dott and brought it back to Paris and reintroduced it to skeptical colleagues. He ultimately performed over 1,000 transsphenoidal hypophysectomies and also introduced the use of intraoperative fluoroscopy 7) 8) 9).