Assessment of Bony Anatomical Variations of Paranasal Sinuses and Nasal Cavity: A Cone Beam Computed Tomography Study

Purpose: Air-filled and bony surrounded structures around the nasal cavity are defined as paranasal sinuses and are effective in the development of facial structures, jaws and airway. Although these structures are separated from each other by thin bone lamina, they are connected via ostiums. Paranasal sinuses are associated with other anatomical structures such as internal carotid artery, orbit, cavernous sinus, optic nerve. Knowledge of the anatomy and variations of the paranasal sinuses is very important in terms of applications such as functional endoscopic sinus surgery, implant surgery involving posterior maxilla and complications that may occur. Methods: In our study, a total of 180 cone beam computed tomography (CBCT) images containing all of the paranasal sinuses were evaluated retrospectively in terms of anatomical variation presence or absence. Results: The most common anatomic variations in our study were agger nasi cell (80.6%), concha bullosa (65.6%) and septum pneumatization (60.3%), while the least observed variations were sphenomaxillary plate (2.1%), second middle turbinate (1.8%) and concha bullosa of the inferior turbinate. (1.7%). Conclusion: Anatomical variations of paranasal sinuses particularly in the osteomeatal complex (OMC), can obstruct sinus drainage, leading to chronic inflammation. Due to their proximity to dental structures, preoperative imaging is crucial to avoid surgical complications. While computed tomography (CT) scans provide the best diagnostic accuracy for paranasal sinuses evaluation, high radiation exposure doses risks to sensitive tissues. In 3-dimensional radiological examination of the paranasal sinuses, CBCT stands out as a good option due to its lower radiation dose and cost effectiveness.