Article

Anatomical and Morphometric Study of the Bony Nasolacrimal Canal Using Computed Tomography

Department of Ophthalmology, Korea University College of Medicine, Seoul, Republic of Korea.
Ophthalmologica (Impact Factor: 1.87). 10/2011; 227(3):153-9. DOI: 10.1159/000331986
Source: PubMed

ABSTRACT 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.
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.
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).
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.

0 Followers
 · 
126 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Purpose: To compare the minimum diameter of the nasolacrimal canal and its location between patients with or without primary acquired nasolacrimal duct obstruction (NLDO) in a Japanese population. Methods: One hundred one patients with unilateral primary acquired NLDO (Group A, 101 affected sides; Group B, 101 unaffected sides) and 50 non-NLDO patients (Group C, 100 sides) were included. Anteroposterior and transverse diameters were measured at the canal entrance and the shortest point using contiguous 1-mm axial computed tomographic images. Canal shapes were classified into 2 types: the "funnel" type (a canal with both minimum diameters at the canal entrance) and the "hourglass" type (a canal with at least one minimum diameter in the canal). The distance from the entrance to the part with the shortest diameter was measured on sides with the hourglass type. Results: The funnel type was found more frequently in Groups A and B than in Group C (p < 0.050), although a difference was not found between Groups A and B (p = 0.778). The distance of the transverse diameter was significantly shorter in Groups A and B than Group C (p < 0.050), although no significant difference was found in this distance between Groups A and B (p = 1.000). There were no significant differences between the groups for each value except for the above mentioned (p > 0.050). Conclusions: Primary acquired NLDO patients exhibited the funnel type more frequently or there was a shorter distance from the entrance to the part with the shortest diameter than non-NLDO patients, which may enhance the risk of primary acquired NLDO.
    Ophthalmic Plastic and Reconstructive Surgery 08/2014; 30(5). DOI:10.1097/IOP.0000000000000238 · 0.91 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To determine the impact of patient positioning and scan orientation on the appearance of air in the nasolacrimal drainage system on computed tomography (CT) imaging, and the repeatability of the observations. This was a retrospective analysis of CT images for 92 patients. Air was found to be present more fully in the upright-position group as compared with the supine-position group. Comparing axial and coronal scan orientation, no difference in aeration was found, except for the nasolacrimal duct in the upright-position group. Patient position should be accounted for in diagnostic conclusions and treatment decisions based on CT.
    Clinical ophthalmology (Auckland, N.Z.) 01/2015; 9:469-73. DOI:10.2147/OPTH.S80752
  • [Show abstract] [Hide abstract]
    ABSTRACT: PURPOSE:: To determine the narrowest diameter of the bony nasolacrimal canal. METHODS:: Fifty-eight bony nasolacrimal canals from 29 Japanese cadavers (12 men and 17 women; average age at death, 83.4 years; range, 70-99 years) had been fixed in 10% buffered formalin before use. After exposing the medial (44 canals) or posterior half (14 canals) of the bony nasolacrimal canal, the part with the shortest anteroposterior or transverse diameter was determined on inspection. These positions from the canal entrance were measured, and the distance ratio, indicating where the shortest diameter was located in relation to the total length of the canal, was calculated. RESULTS:: The shortest anteroposterior and transverse diameters were at the entrance to the canal in 32 of 44 canals (72.7%) and in 9 of 14 canals (64.3%), respectively. In the other canals, the shortest anteroposterior and transverse diameters were located at an average of 3.6 and 5.6 mm from the entrance, and the distance ratios were 29.0% and 46.7%, respectively. The mean shortest anteroposterior and transverse diameters were 5.6 and 5.6 mm, respectively. CONCLUSIONS:: The shortest anteroposterior and transverse diameters were at the entrance of the canal in most of the bony nasolacrimal canals. These results are comparable with the rate of obstruction at the canal entrance in primary acquired nasolacrimal duct obstruction.
    Ophthalmic plastic and reconstructive surgery 04/2013; 29(4). DOI:10.1097/IOP.0b013e31828de0b0 · 0.91 Impact Factor