Purpose: To evaluate the anatomy of the sphenoid ostium (SO), which has so far only been investigated with the aid of two-dimensional computed tomography (CT) or using a cadaver, from a new point of view through the use of 3D CT for the first time.
Methods: We have evaluated 50 patients who had CT angiography done for different reasons. The sphenoid sinus types and the SO were evaluated three dimensionally. The average diameters of the sphenoid ostia, and their distances to the midline, as well as to each other and the choana have been measured. In addition, the SO were categorized according to their shapes.
Results: The average age of the patients was 48.5. No SO was found in seven cases (14 %). The average distance of the SO to the midline was 2.78 mm on the right side and 2.77 on the left. Four different shapes of SO were determined; round, oval, irregular and linear. The average distance of the right and left SO to the choana was 15.22 ± 0.95 and 14.87 ± 1.11 mm, respectively. No statistically significant difference was found between the male and female sexes with regard to the calculated diameters and shapes of the SO (p > 0.05).
Conclusion: The anatomy of the sphenoid sinus and the SO varies widely from individual to individual. We have demonstrated in our study that these anatomic variations could be evaluated pre-operatively. Using this imaging technique, surgeons can make a pre-operative 3D evaluation of the sphenoid ostium, encountered in the surgery and thus achieve better orientation.