Location of the nasolacrimal canal in relation to the high Le Fort I osteotomy.

The positional relationship between the high-level Le Fort I osteotomy and the nasolacrimal canal was studied in standard posteroanterior and lateral cephalograms made of 100 adult dry skulls after orienting the Frankfort horizontal of each skull to the natural horizontal plane. The simulated high-level Le Fort I osteotomy in all of the 100 skulls was under the level of the inferior orifice of the nasolacrimal canal by a mean distance of 5.2 mm (range, 0.5 to 11.5 mm). The average distance between the canal orifice and a line which extended from the lacrimal fossa to the anterior attachment of the inferior turbinate was 0.7 mm (range, 2.0 mm medially to 3.5 mm laterally). The maxillary height was strongly correlated to the height of the infraorbital foramen (r = .59, P less than .001) and the simulated osteotomy (r = .57, P less than .001). The results indicate that the osteotomy, when made just beneath the infraorbital foramen and extending into the piriform rim at the level of anterior attachment of the inferior turbinate, will usually not jeopardize the nasolacrimal duct within its bony canal. A line drawn from the lacrimal fossa to the anterior attachment of the inferior turbinate on the anterior aspect of the maxilla is a good approximation of the course of the nasolacrimal canal.