A cross-sectional study of sphenoid sinus through gross and endoscopic dissection in North Karnataka, India

Abstract

Sphenoid sinus has got importance due to trans- sphenoid approach to the pituitary gland. This study is an attempt to know the variations in North Karnataka population, through cadaveric dissection and CT scan study. Objective: We want to study variations in sphenoid sinus and its percentage in North Karnataka population. Material and Methods: Endoscopic examination and dissection of sphenoid sinus was carried out in 30 cadavers (three female and 27 male) using 0o, 30o, 70o rigid nasal endoscopes. Sections were then made in the sagittal plane to confirm the anatomical findings and to take the necessary measurements with millimeter strips. Results: In six of cadavers pre-sellar, in four it was sellar and in 20 it was post-sellar while conchal type of sphenoid sinus was absent. The septa terminated on bone covering internal carotid artery (ICA) in seven cadavers while in two cadavers they terminated on the bone covering Optic nerve (ON). Findings of CT scan study were pre-sellar-8, sellar-14 and post-sellar-37 and in case of one subject left side sinus was conchal. Pneumatization of greater wing of sphenoid was observed in two sinuses, of pterygoid process in four sinuses and of anterior clinoid process in two sinuses. We also found onodi cell in one sinus. Conclusion: Sphenoid sinus shows various types of pneumat­ isation, and this place the sinus in close proximity to important neurovascular structures that are present around the sinus. Newer techniques are used to confirm surgical landmarks making these techniques very safe.