Nasolacrimal Canal Topography in Relation to the Maxillary Position: CBCT Insights into Le Fort Osteotomy and Fixation Safety

Background/Objectives: Le Fort I osteotomy is a widely performed surgical procedure for correcting maxillary deformities, but it carries the risk of rare complications, including nasolacrimal duct (NLD) injury. This study evaluated the anatomical relationship between the nasolacrimal canal (NLC) and the maxilla across different skeletal patterns via cone-beam computed tomography (CBCT) to define safer zones for fixation during orthognathic surgery. Methods: This retrospective study included 76 patients (152 canals) scheduled for orthognathic surgery. The participants were classified into retrognathic, orthognathic, and prognathic groups based on SNA values. Four linear distances were measured on sagittal CBCT sections: from the superior (SL), middle (ML), and inferior (IL) points of the NLD to the anterior maxillary border and from the canine apex to the inferior NLC point (IC). A total of 608 measurements were analyzed via ANOVA, the Kruskal–Wallis test, and post hoc tests, with significance set at p < 0.05. Results: The ML distance was significantly greater in the prognathic group than in the retrognathic and orthognathic groups (p < 0.001). The IL distance was significantly shorter in retrognathic individuals (p < 0.001). No significant differences were found in SL (p = 0.063) or IC (p = 0.141) among the groups. Conclusions: The proximity of the NLC to the maxilla varies according to the skeletal pattern. The retrognathic maxilla results in shorter IL distances, suggesting increased risk during fixation, whereas the prognathic maxilla results in greater ML distances. Preoperative CBCT-based individualized evaluation is recommended to optimize fixation and reduce NLD injury risk in Le Fort I osteotomy.