Anatomical and morphometric study of the bony nasolacrimal canal using computed tomography

Aims: To determine the diameters, angles and sectional area of the bony nasolacrimal canal using computed tomography for obtaining detailed anatomical knowledge of the drainage system and utilizing these measurements in planning interventions for nasolacrimal duct obstruction in adults and children. Methods: Using standard computed tomographic images, we measured the diameters, angles and sectional area of the bony nasolacrimal duct in 228 patients without nasolacrimal duct disease. Results: There was no statistically significant difference in other parameters between males and females. In particular, age had a significant effect on the angle between the bony nasolacrimal canal and the nasal floor in the pediatric patients (<10 years; p = 0.00), and pediatric patients had more acute angles than adult patients (>10 years old). Conclusions: In nasolacrimal probing of congenital nasolacrimal duct obstruction, the probe should be passed more to the posterior part of the nasal cavity. In other words, the distal part of the probe should form a more obtuse angle with the forehead in pediatric patients than in adults. This study may contribute to the establishment of a detailed anatomical and morphometric baseline of the bony nasolacrimal canal and provide useful information for the planning of interventions for nasolacrimal duct obstruction in adults and children.