The surgery of pituitary tumors began in 1906, when Schloffer1attacked such a lesion by the endonasal or transphenoidal route. His familiarity with the nasal accessory sinuses led him to select this approach. Subsequently this technic was modified by Kanavel2in 1909 and by Halstead3and by Hirsch 4 in 1910. In 1912 Cushing5further modified the transphenoidal approach in minor details and emphasized its value in the treatment of pituitary adenomas by reporting a large series of cases. However, the disadvantages of the endonasal route, lack of satisfactory exposure, which handicaps the operator especially if the adenoma is solid, danger of meningitis and the technical difficulties inherent in the procedure, forced the development of an intracranial approach. In 1909 Krause,6in 1913 Frazier7and in 1920 Heuer8described an approach from above through the anterior cranial fossa which, with minor modifications resulting