Computed tomography evaluation of the sphenoid sinus and the vidian canal

Computed tomography evaluation of the sphenoid sinus and the vidian canal. Objectives: To understand the relationship between the vidian canal and surrounding structures of the sphenoid sinus, and to discover factors related to the formation of various canal corpus types using preoperative computed tomography (CT). Methods: This retrospective study included 265 patients with 570 sides of identifiable vidian canal. All patients underwent paranasal sinus CT with 3-mm contiguous coronal and axial sections. Subsequently, the relationships amongst the different canal corpus types, pneumatization of the pterygoid recesses, morphometric parameters, and surrounding anatomical landmarks were investigated. Results: Dehiscence of the bony roof of the canal was much more commonly seen in canal corpus types 2 and 3 than type 1 (p<0.001). The presence of pterygoid recess pneumatization was more commonly seen in canal corpus types 2 and 3. More extensive pneumatization of the pterygoid recess was associated with a greater distance from the canal to the foramen rotundum (p<0.001), but there were no significant differences in the distance from the vidian canal to the vomerine crest (p = 0.465). Conclusion: Pterygoid recess pneumatization might alter the position of the vidian canal relative to the sphenoid corpus and the distance to the foramen rotundum, but not the distance to the vomerine crest. Therefore, analyzing the canal corpus type and pneumatization of the pterygoid recess may play a key role when choosing a surgical approach in endoscopic vidian neurectomy.