Factors affecting dimensions of the ethmoid infundibulum and maxillary sinus natural ostium in a normal population

OBJECTIVES: To investigate the ethmoid infundibulum (EI) and maxillary sinus natural ostium (MSNO) dimensions in normal sinuses of the Asian population; identified variation between sides, gender, and age groups; and to assess the effects of such variation on the measurements. METHODS: We assessed EI dimension and MSNO diameter in computed tomography (CT) scans of the normal paranasal sinus of 100 patients who underwent trans-sphenoid endoscopic surgery. We compared demographic data and multiple anatomical variations. RESULTS: The gap difference in EI length between the right and left sides significantly differed from 0 (0.47±1.38 mm). We found wider EI in people aged ≥60 years (2.44±0.59 mm), compared to people aged <60 years (2.25±0.31 mm). Ethmoid infundibulum length was greater among individuals with Haller cells (8.84±1.56 mm) than in individuals without them (7.92±1.47 mm). Furthermore, MSNO diameter was greater with accessory ostium (3.48±0.77 mm versus 3.02±0.72 mm, presence versus accessory ostium absence). CONCLUSION: Multiple factors may affect EI and MSNO dimensions. Ethmoid infundibulum length differed between both sides. Ethmoid infundibulum width differed between individuals aged ≥60 years and individuals aged <60 years. Haller cells and accessory ostium presence were associated with significant differences in those measurements.