Retrospective analysis of changes in nasolacrimal canal with cone beam computerized tomography in dentofacial deformity surgery

Orthognathic surgery is a procedure applied in cooperation with Oral and Maxillofacial Surgery and Orthodontics specialities in patients with dentofacial anomalies who have completing their developmental period. The most commonly used orthognathic surgical approaches today are Le Fort I osteotomy for the maxilla and bilateral sagittal split ramus osteotomy for the mandible. During the maxillary Le Fort I osteotomy, the location of many anatomical structures' changes. Of these, the nasolacrimal canal, which is adjacent to the surgical field, is an anatomical structure that requires utmost care during the surgical operation while forming the incision line and positioning the screws-plates. For this purpose, cone beam computed tomography of 50 patients who completed their growth and development and underwent Le Fort I operation were retrospectively analysed. In the preoperative and postoperative cone-beam computed tomography images of these patients, the narrowest diameter, widest diameter and length of the nasolacrimal canal were measured. While planning the surgery, it should be taken into consideration that the nasolacrimal canal will narrow and shorten after the operation. In line with these measurements, the results we obtained in our study revealed the opinion that many postoperative complications can be avoided by examining the preoperative cone beam computed tomography images in detail.