The anatomical variations in the neurovascular relations of the sphenoid sinus: An evaluation by coronal computed tomography

Aim: The sphenoid sinus is deeply situated in the skull and is the least accessible paranasal sinus. The sphenoid sinus is surrounded by vital structures such as the optic nerve and internal carotid artery, and therefore additional radiological assessment of the sphenoid sinus and the related neurovascular structures is inevitable before surgery. The aim of this study was to note the anatomic variations in the relationship of these structures with the sphenoid sinus by analyzing the coronal computed tomography (CT) scans. Material and methods: The consecutive coronal CT scans of 100 patients that included 43 males and 57 females were evaluated. Results: Variations in the neurovascular boundaries of the sphenoid sinus were a common finding in the present study and were seen in as many as 66% of the cases. Variations involving the Vidian canal were the commonest in our study and were seen in around 42%, followed by those involving the bony canal for internal carotid artery, 33%; maxillary nerve, 21 % and optic nerve, 9%. Conclusion: These variations do not represent disease as such, but may increase the risk of endoscopic mishaps. CT of the paranasal sinus region is therefore an essential prerequisite prior to sinonasal and trans-sphenoidal surgeries.