Anatomical variations of sphenoid sinus on cone beam computed tomography.

Introduction: The surgical approach to the sphenoid sinus (SS) is one of the most challenging aspects of endoscopic surgery due to its proximity to critical structures. To minimize risks, computed tomography (CT) aids in navigational guidance. Although cone beam computed tomography (CBCT) has lower contrast resolution, it offers improved precision, reduced radiation exposure, and faster imaging, making it a viability as a preoperative tool.

Methods: We randomly selected 75 patients from 707 who underwent CBCT between January and December 2023. Two observers evaluated SS anatomy with consensus. Statistical analyses were conducted using Excel® and Jamovi®.

Results: Anatomical variations were documented, with prevalence rates as follows: sphenoethmoidal cell (15%); optic nerve (ON) protrusion (21%) and dehiscence (4%); internal carotid artery (ICA) protrusion (31%) and dehiscence (0%); vidian canal (VC) protrusion (39%) and dehiscence (6%); foramen rotundum (FR) protrusion (23%) and dehiscence (5%); anterior clinoid process (ACP) pneumatization (20%); pterygoid process (PP) pneumatization (33%); conchal (1%), presellar (7%), sellar (36%) and postsellar type (56%) SS; and intersphenoidal septum (47%). Statistically significant correlations were observed between ACP pneumatization and ON protrusion (p < 0.001) and dehiscence (p = 0.018), and ICA protrusion (p = 0.001). PP pneumatization was significantly correlated with VC protrusion (p < 0.001) and dehiscence (p = 0.011), and foramen rotundum protrusion (p < 0.001).

Discussion/conclusion: Our CBCT findings largely aligned with CT data in existing literature. Due to its faster acquisition and lower radiation exposure, CBCT shows potential as a preoperative evaluation method for assessing the SS.