What is the impact of lateral nasal wall osteotomy depth on pterygomaxillary separation during a Le Fort I downfracture?

Background: The study aimed to investigate the effect of customized lateral nasal wall osteotomy (LNO) on the lateral nasal wall (LNW) and pterygomaxillary junction (PMJ) separation during Le Fort I. We hypothesized that customized LNO on the LNW affect the PMJ separation type.

Material and methods: This prospective, controlled, randomized study included forty-three patients were randomly assigned to either the conventional or customized (study) osteotomy groups. In the study group, LNW depth was measured before surgery in the axial section of the CT scan, and LNO was performed at a depth of 2 mm less than the measured distance. In the conventional osteotomy group, LNO was performed at 30 mm for females and 35 mm for males. Patients with cleft lip and palate, previous orthognathic surgery, or rhinoplasty were excluded. Separation types were classified as follows: LNW types; Type1-from the osteotomy line; Type2- 2-4 mm above the osteotomy line; Type3- 4 mm or more above the osteotomy line. PMJ types; Type1-including the tuber maxilla; Type2-from the pterygomaxillary junction; Type3-including the pterygoid plates. Chi-square tests were conducted to determine whether there was a significant correlation between groups and LNW separation types, groups and PMJ separation types and groups, and LNW separation type and PMJ separation type. A P value of < .05 was considered statistically significant.

Results: In both the conventional (P=0.052) and the study groups (p=0.828), there was no significant difference between LNW depth. Type 1 (P=0.0003) and Type 2 (P=0.0051) LNW separation types presented a significant difference between groups. A chi-square test showed a significant correlation between the surgical groups and PMJ separation patterns (P<0.05).

Conclusions: Customized LNO optimizes the LNW and PMJ separation. Facilitates the Le Fort I surgery and decrease unintentional fracture of the PMJ.