Anatomical study on endoscopic endonasal transsphenoidal surgery for pituitary tumors

Objective: To provide anatomical basis for endoscopic endonasal transsphenoidal surgery for pituitary tumors. Methods: The structures in sellar area were observed and measured in 25 adult cadaveric head specimens, and the structures in sphenoidal sinus and sellar area were observed under the operating endoscope in 9 fresh adult cadaveric head specimens. Results: The height of diaphragma sellea turcica was 5.5±0.6 mm. The sagittal and the transverse diameter of foramen of diaphragma sellea turcica were 6.2±1.3 and 6.5±1.5 mm respectively. The distances from the anterior edge of it to the anterior edge of pituitary stalk and tuberculum sellae were 2.5±1 .1 and 3.4±1.3 mm. At the cranial end, the transverse diameter of optic nerve was 5.0±0.4 mm The distance between bilateral optic nerves was 13.7±2.3 mm. The distance from anterior border of opticochiasma to the midpoint of sulcus prechiasmaticus was 6.8±1.3 mm The transverse diameter of chiasma was 11.5±1.4 mm. Conclusion: Neurosurgeon should be familiar with the structures of sellar area and the bottom of sphenoidal sinus and take advantage of these anatomical landmarks to perform the endoscopic endonasal transsphenoidal pituitary surgery step by step.