Computed tomographic assessment of the lacrimal sac fossa in the Japanese population.

PURPOSE: To analyze the morphology of the lacrimal sac fossa in the Japanese population using computed tomographic images.

MATERIALS AND

METHODS

One-hundred-fifty-five Japanese patients diagnosed with unilateral orbital fracture were retrospectively reviewed. Measurements of the dimensions of the lacrimal sac fossa were taken on three anatomical planes (upper, middle, and lower planes) using a digital caliper/protractor tool.

RESULTS

The mean maximum thickness of the maxillary bone at the upper, middle, and lower planes of the lacrimal sac fossa were 4.60 mm, 5.07 mm, and 6.30 mm, respectively. The midpoint thickness of the maxillary bone at each plane were 3.04 mm, 3.00 mm, and 2.17 mm, respectively. The lacrimal bone thickness at each plane were 1.13 mm, 1.13 mm, and 1.08 mm, respectively. The proportion of the lacrimal sac fossa comprising of the lacrimal bone at each plane were 39.00%, 42.05%, 38.92%, respectively. On the middle plane, the mean angle between the lacrimal bone and sagittal plane was 131.92°.

CONCLUSIONS

In Japanese patients, the proportion of the lacrimal bone on the lacrimal sac fossa tended to be of greater proportion compared to studies done on other races. The mean angle of the lacrimal sac fossa seemed to be comparatively high. These results indicate that performing an osteotomy during dacryocystorhinostomy could be relatively easier in the Japanese population compared to other races.