Anatomical Analysis of Sphenoid Sinus and its Surrounding Structures in Cone-beam Computed Tomography Images: A Retrospective Cross-sectional Study

Abstract Background Anatomical analysis of the sphenoid sinus is important because of its proximity to vital neurovascular structures. The aim of this study is investigating the anatomy of the SS and its surrounding structures in CBCT images. Methodology: In this retrospective cross-sectional study, 201 cone-beam computed tomography (CBCT) radiographs were analyzed. The analyzed images included the type of SS, protrusion of ICA and optic nerve and foramen rotundum, vidian canal type, the Onodi cell, pneumatization to surrounding bones, the ostium, the septum. The data were analyzed using chi-square and the t-test in SPSS 24 at a significance level of 0.05. Results The tilted septum had the highest frequency (46.3%). Ostium was bilateral in most images (56.2%). The protrusion of the ICA (54.7%) and optic nerve (62.2%) was smooth in most images. Foramen rotundum protrusion and Onodi cell prevalence were 25% and 22.9%, respectively. The postsellar type of sinus had the highest frequency (71.1%). Vidian canal Grade II had the highest frequency (40.3%). Greater wing pneumatization had the highest frequency (51.7%). No statistically significant relationship was found between the optic nerve protrusion and Onodi cell (P-value < 0.05). There was a significant relationship between the pneumatization of the pterygoid process and the protrusion of the vidian canal, and the foramen rotundum protrusion (p-value < 0.001). Conclusion CBCT imaging is very effective in the anatomical analysis of the SS and its surrounding structures. The postsellar type had the highest frequency.Vidian canal Grade II had the highest frequency; greater wing pneumatization was observed in more than half of the images; the most common type of septum was tilted; ostium was bilateral in most cases; the protrusion of the ICA and optic nerve was mostly smooth.