Evaluating the Anatomical Variations of the Sphenoid Sinus and Its Adjacent Structures: A Cone-Beam Computed Tomography Analysis

The sphenoid sinus is a common area for performing paranasal surgeries. This sinus and its adjacent vital structures show anatomical variation. awareness of existence of these variations can affect the complications of functional endoscopic sinus surgery.

Methods & Materials: 

120 maxillofacial CBCT images belonging to 57 women (47.5%) and 63 men (52.5%) with an average age of 39.00±13.84 years were analyzed using Romexis viewer 3.8.0 software. For each sample, the following variables were evaluated and compared in two different sexes and ages: Posterior extension of sphenoid sinus pneumatization in relation to the sella turcica, Extension of pneumatization to the clinoid and pterygoid process and whether it is unilateral or bilateral, The presence or absence of protrusion, dehiscence or septa connected to the nerve in the case of the optic canal (OC), vidian canal (VC) and foramen rotundum (FR) and its unilateral or bilateral presence,The presence or absence of a protrusion, dehiscence or septa connected to the carotid canal (CC) and its unilateral or bilateral presence One-way ANOVA, independent t-test, chi-square, and Fisher's exact tests were used for statistical analysis.

The most common pattern of sphenoid sinus pneumatization in relation to the sella turcica was post-sellar (69.1%) pattern.There was a significant relationship between the pattern of sphenoid sinus pneumatization in relation to sella turcica and protrusion/dehiscence/septa connected to CC (P=0.001, 0.032, 0.027) and VC(P=0.023) dehiscence. Pneumatization of the clinoid process was also significantly related to OC, FR and CC protrusion (P<0.05). Pneumatization of pterygoid process and greater wings of sphenoid had a significant relationship with protrusion of VC, FR and protrusion/dehiscence/septa connected to CC (P<0.05). The pattern of sphenoid sinus pneumatization was independent of gender.

The higher prevalence of high-risk anatomical variations in the population of northeastern Iran, indicate a high risk of serious complications in this area.