Prevalence of Anatomical Variations of Sphenoid Sinus and Its Adjacent Structures Pneumatization and Its Significance: A CT Scan Study.

The purpose of our study was to assess the prevalence of variations and type of sphenoid sinus and its adjacent structures pneumatization and its significance. This prospective study included 114 patients who underwent CT of the paranasal sinuses. The CT scan in axial, coronal and mid sagital section were analysed to assess the type of pneumatization of the sphenoid sinus and its adjacent structures like; anterior clinoid process, greater wing of sphenoid and pterygoid process. The sphenoid sinus pneumatization was classified into Conchal, Presellar, and Sellar types, later comprised of sellar and post-sellar types. Out of 114 cases of pneumatized sphenoid sinus, 5.2% cases were conchal type, 26.3% cases Presellar type and 68.4% cases sellar type. The one or more adjacent structures was pneumatized in 71 (62.2%) of cases. The adjacent structures which found to be pneumatized are anterior clinoid process in 26.3%, Pterygoid process in 23.6%, and greater wing of sphenoid in 12.3% cases. The pneumatization of adjacent structures was more prevalent in sellar type of sphenoid sinus, followed by pre-sellar type and no pneumatization in conchal type. The anterior clinoid process pneumatization was present in 26.1% of cases, in which 3 (2.6%) cases in pre-sellar type and 27 (23.5%) cases in sellar type. It was unilaterally pneumatized in 13 (11.4%) and bilaterally in (17 (14.9%) cases. The pterygoid process pneumatization was present in 27 (23.6%) of cases, unilateral in 16 (14%) cases and bilateral in 11 (9.6%) cases. The Greater wing of sphenoid pneumatization was found in 14 (12.3%) cases, no cases in conchal types, 2 (1.8%) in pre-sellar type, and 12 (10.4%) in sellar type There was no statistically difference found in between right and left side of sphenoid sinus and its structure pneumatization. The extent of pneumatization of the sphenoid sinus has clinical and surgical implications in sinus diseases, sellar and central skull base lesions.