Variations of sphenoid sinus and their impact on related neurovascular structures

The sphenoid sinus is deeply seated in the skull and is the most inaccessible paranasal sinus intimately related to numerous vital neural and vascular structures. This work determines the incidence of the different anatomical variations of sphenoid sinus as detected by CT scan and their impact on related neurovascular structures, for the safe removal of inter sphenoid and pituitary lesions. The CT scan of 20 patients were reviewed regarding the different anatomical variations of the sphenoid sinus: degree of pneumatisation, protrusion of internal carotid artery (ICA), optic nerve (ON), and dehiscence of the walls of ICN and ON, and the septation pattern. There were 10 cases with protrusion and 9 cases of dehiscence of the bony wall on ICA, 13 cases of optic nerve protrusion and 10 cases of dehiscence. Sellar pneumatisation was present in majority of the patients (55%), with 5 patients having presellar (25%) and 4 patients having post sellar pneumatisation (20%). Different anatomical configurations of the sphenoid sinus can seriously affect the access to the sella via the nose. The surgeon should be aware of these findings preoperatively to reach the sella safely and effectively.