Ramanna H.C.1 , Samarth S. Gowda2 , Jithendra N.3 , Vijay Kumar K.R.4
BACKGROUND One of the most vital structures in the anterior skull base surgeries is sphenoid sinus. Sellar, parasellar, suprasellar and clival lesions can be easily accessed using sphenoid sinus and is one of the most variable of all the paranasal sinuses in terms of its surrounding anatomical relationships. It also serves as a natural route for surgical entry to the middle cranial fossa and the cave of Meckel. Further, foramen of Rotundum and the canal of Vidian serve as vital gateways to important neurovascular structures, and their close proximity to the sphenoid sinus makes it necessary for the operating surgeon to have a better understanding of this anatomical ’Holy trinity’. By shedding light on this complex anatomical relationship through the course of our study, we hope to be of better assistance to the operating surgeons. METHODS 100 consecutive CT scans of the paranasal sinuses performed for any cause, were reviewed retrospectively to look for the sphenoid sinus and its anatomical relationship to the foramen rotundum and vidian canal. All the computed tomography scans were performed using Philips Ingenuity 128 slice CT scanner. 3 mm slice contiguous images were taken, and 1 mm slice reconstruction was performed. Images were reviewed in three orthogonal planes. RESULTS Based on the study, the most common type of foramen rotundum was ’Type IIB’ and the most common position of foramen rotundum in relation to sphenoid sinus based on lateral pterygoid plate was found to be the ‘online’ type. The most common variation in the Vidian canal anatomy was found to be the ‘Type II’ canal. No association was found between types of foramen rotundum and vidian canals with position of foramen rotundum. CONCLUSIONS Knowledge of the complex anatomical relationship of sphenoid sinus is important for skull base surgeries. Results of the study help us to understand the most common anatomical variations, thus aiding in better surgical outcomes.
