Anatomical and morphometric study of the bony nasolacrimal canal using computed tomography.
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.
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ABSTRACT: PURPOSE:: To examine the relative positions of the lacrimal fossa (LF) and the bony nasolacrimal canal (BNLC) in relation to each other and a reference plane. METHODS:: Forty-two orbits and BNLCs from 21 Asian cadavers (9 men and 12 women; average age at death, 84.4 years; range, 70-99 years) had been fixed in 10% buffered formalin before use. After exposing the LF and the medial half of the BNLC, the authors measured the angles of the longitudinal axis of the LF and the BNLC relative to the aesthetic horizontal plane respectively. Based on these values, the relative orientation of the LF and the BNLC was determined and defined in terms of Δ BNLC-LF. A positive Δ BNLC-LF represents a nasolacrimal canal that descends posteriorly relative to the LF. RESULTS:: The mean LF, BNLC, and Δ BNLC-LF were 9.5°, 19.8°, and 10.3°, respectively. In 39 passages (92.9%), the Δ BNLC-LF was positive, representing a nasolacrimal canal that is more posteriorly oriented than the LF. In 3 passages (7.1%), the Δ BNLC-LF was equal to or less than 0°; 2 of them (4.8%) had a straight course and 1 passage (2.4%) had a negative value. CONCLUSIONS:: In most patients, the BNLC is directed more posteriorly than the LF. This finding may help in preventing an inadvertent false passage during probing and intubation in patients with epiphora.Ophthalmic plastic and reconstructive surgery 10/2012; · 0.69 Impact Factor
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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; · 0.69 Impact Factor