Anatomical Variations of the Paranasal Sinuses and Nasal Cavity and their association with Radiologically Evident Sinus Disease on Computed Tomography

Abstract

Introduction: Sinonasal anatomical variations, frequently seen on paranasal sinus CT, can predispose disease by obstructing ventilation and mucociliary clearance. Their recognition is essential for accurate diagnosis and effective surgical planning. This study evaluated the prevalence of these variations in Nepalese patients and their associations with gender, ethnicity, and radiologically detected sinonasal disease.

Methods:This cross-sectional study retrospectively reviewed 348 non-contrast paranasal sinus CT scans performed at Bir hospital from November 2024 to May 2025. Variations assessed included deviated nasal septum (DNS), concha bullosa, agger nasi cells, uncinate process pneumatization, Haller cells, Onodi cells, paradoxically curved middle turbinate (PCMT), and sinus septations. Sinonasal disease was determined radiologically. Associations with gender, ethnicity, and disease were analyzed using Chi-square or Fisher’s exact tests (p < 0.05 significant).

Results: The mean age of patients was 39.9 ± 18.4 years; 180 (51.7%) were male .The most common variation was DNS at 87.9%, followed by agger nasi cells (38.7%), concha bullosa (26.4%), sinus septations (25.3%), and Haller cells (16.3%). Radiological sinonasal disease was present in 217 patients (62.4%). No significant differences in anatomical variations were found by gender or ethnicity (all p > 0.05). Significant associations with disease included uncinate process pneumatization, concha bullosa, agger nasi cells, and Haller cells. DNS was paradoxically more prevalent in patients without disease, likely due to referral bias.

Conclusions: Sinonasal anatomical variations are common in the Nepalese population and several variants particularly those involving the Osteomeatal complex are significantly associated with radiologically evident sinus disease.