Variations in sphenoid sinus anatomy with special emphasis on pneumatization and endoscopic anatomic distances

Objectives: The purpose of this study was to presentthe morphometry and pneumatization of the sphenoidsinus in detail for the neurosurgeon for transnasalapproach to the hypophyseal tumors and especially forfunctional endoscopic sinus surgery.Methods: One hundred and eighty midsagittalmagnetic resonance images, 48 bones and 29hemi-sectioned cadaveric heads obtained from EgeUniversity, Faculty of Medicine, Departments ofAnatomy and Radiology were used in 2003. Thesphenoid sinuses were classified into sellar, pre-sellar,conchal and post-sellar types according to the extent oftheir posterior limits. Different measurements based onthe surgical approach and sinus size were performed.Results: Conchal type sinus was observed in 1.9%,pre-sellar type 9%, sellar type 52.9% and post-sellar type36.2% of the specimens. Conchal type sphenoid sinuswas not observed in males, but in 1.7% of females.Pre-sellar type was observed in 5.6% of males and 2.8%of females. Sellar type was found in 24.4% of males and23.9% females, and post-sellar type in 19.5% of malesand 22.2% of females. The sphenoid sinus length at theupper and lower parts was 13.51±3.25mm and24.57±6.65mm. The sphenoid sinus height at the anteriorand posterior parts was 21.27±4.25mm and14.5±4.07mm. Distance from the ostium to limen was56.6±5.6mm and from ostium to sill was 64.6±6.11mm incadaveric specimens. In MR images, distance from theostium to the sill was 68.7±5.9mm and from sella to sill82.8±6.2mm.Conclusion: Sphenoid sinus variations observed inpneumatization, size, localization and shape areimportant in providing a better surgical approach andavoiding surgical complications.