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.