Anatomical Variations of the Sphenoid Sinus and its Adjacent Critical Structures Using Cone Beam Computed Tomography: A Cross-Sectional Study

Solmaz Valizadeh; Mohammadhosein Rezaiefard; Masoud Mohammadpour; Navid Jamalzadeh

doi:10.18502/jimc.v6i2.12244

Solmaz Valizadeh Department of Oral and Maxillofacial Radiology, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Mohammadhosein Rezaiefard Department of Oral and Maxillofacial Radiology, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Masoud Mohammadpour Department of Oral and Maxillofacial Radiology, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Navid Jamalzadeh Department of Oral and Maxillofacial Radiology, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran

DOI: https://doi.org/10.18502/jimc.v6i2.12244

Keywords: Carotid artery, Optic nerve, Prevalence, Septa

Abstract

Background: The aim of the study was to determine the anatomical variations of the sphenoid sinus and its adjacent critical structures using Cone-Beam Computed Tomography (CBCT).

Methods: This cross-sectional study was conducted on CBCT scans of 67 females and 84 males between 18 to 67 years. Presence/ absence of intersphenoid septa, sphenoid sinus pneumatization and its type (conchal, presellar, sellar, and postsellar a and b), protrusion of the optic canal and carotid canal into the sphenoid sinus, optic canal and carotid canal dehiscence, and Anterior Clinoid Process (ACP) pneumatization was evaluated on CBCT scans, and their prevalence and correlation were calculated. Data were analyzed by the Chi-square test (alpha=0.05).

Results:The prevalence of intersphenoid septa was 98.68%. Postsellar type a was the most common type of sphenoid sinus pneumatization with a prevalence of 41.3%. The prevalence of conchal, presellar, sellar and postsellar b types was 0, 11, 30, and 17.7%, respectively. The prevalence of optic canal and carotid canal protrusion into the sphenoid sinus was 50 and 52.7%, respectively. The prevalence of optic canal and carotid canal dehiscence was 48.3 and 40.3%, respectively. The prevalence of ACP pneumatization was 45%. Optic canal and carotid canal protrusion had a significant correlation with ACP pneumatization (p<0.001). Also, carotid canal and optic canal protrusion and dehiscence were significantly correlated with degree of sphenoid sinus pneumatization (p<0.001).

Conclusion: Sphenoid sinus pneumatization significantly increases the likelihood of carotid canal, optic canal protrusion into the sphenoid sinus and their dehiscence, therefore, a preoperative 3D imaging is strongly recommended prior to trans-sphenoidal surgical procedures.