Association of accessory sphenoidal septum with protrusions of sphenoid sinus

Abstract

Purpose: Accessory sphenoidal septum (ASS) is a septal variation that exists in addition to the primary septum of the sphenoid sinus and can be found in or near anatomically essential structures. This study aimed to investigate the relationships between protrusions of vital structures around the sphenoid sinus and the ASSs.

Methods: This cross-sectional retrospective study is based on the analysis of CBCT scans of 314 patients in axial, coronal, and sagittal planes with 0.2-0.3 slice thicknesses. Optic nerve (ON), internal carotid artery (ICA), both ON and ICA, maxillary nerve (MN), vidian canal (VN) and ASSs were detected, and the relationship between protrusions of these vital anatomical structures and ASS was evaluated.

Results: Statistically significant relationship was observed between the right Type 1 ON protrusion (p < 0.05) and left Type 1 ON protrusion (p = 0.001); left Type 3 ON protrusion (p < 0.05); right Type 4 ON protrusion (p < 0.05) and ASS. Statistically significant relationship was also observed between the right ICA protrusion and ASS (p < 0.05). The right Type 1 VN protrusion (p = 0.001); left Type 2 VN protrusion (p < 0.001); right and left Type 3 VN protrusions (p < 0.001) were found to be significantly associated with the ASS.

Conclusions: ASSs have significant associations with some protrusions, and they tend to cause potentially severe complications in endoscopic sinus surgery. This variability requires a comprehensive understanding of regional sphenoid sinus anatomy with detailed three-dimensional tomographic imaging.

Keywords: Accessory sphenoidal septum; Cone-beam computed tomography; Paranasal sinuses/surgery; Protrusion; Sphenoid sinus.