Skeletal Stability Following LeFort I Maxillary Advancement With Rigid Fixation: A Retrospective Study

TL;DR

This study examines how much the maxilla moves back after surgery, finding that larger advancements are more stable and about a quarter of movement is typically lost in the first year.

Contribution

The study identifies that larger maxillary advancements result in greater skeletal stability and quantifies typical relapse rates following LeFort I surgery with rigid fixation.

Findings

Mean horizontal relapse was 1.33 mm, representing 24% of the surgical advancement after one year.

Advancements greater than 5 mm showed significantly lower percentage relapse compared to smaller advancements.

Concomitant mandibular surgery, age, and sex did not significantly affect skeletal stability.

Abstract

Introduction

Postoperative skeletal relapse is the most common complication following LeFort I maxillary advancement, even with modern rigid fixation techniques. This retrospective study aimed to evaluate the magnitude and predictors of horizontal skeletal relapse at one year after Le Fort 1 advancement osteotomy stabilized exclusively with rigid fixation.

Materials and methods

Thirty-two consecutive adult patients (mean age, 25 years) who underwent LeFort I advancement (with or without simultaneous mandibular surgery) between 2018 and 2021 were included after obtaining approval from the institutional ethics committee. All procedures followed a standardized protocol using four L- or straight miniplates at the pyriform and zygomatic buttress regions bilaterally, without routine bone grafting for gaps of ≤6 mm. Digital lateral cephalograms were obtained preoperatively (T0), immediately postoperatively (T1), and ≥12 months postoperatively (T2). The horizontal position of point A parallel to the Frankfort plane was measured using Dolphin Imaging software. Statistical analyses included independent t-tests and multivariate linear regression.

Results

The mean maxillary advancement at T1 was 5.52±1.18 mm. At a mean follow-up of 14.38±1.29 months, mean horizontal relapse was 1.33±0.31 mm, representing 24.06±2.92% of the surgical advancement. Patients with advancements >5 mm (n=19) showed significantly lower percentage relapse (22.07±2.64% vs. 26.06±3.35%, p=0.003) and less overjet relapse (0.27±0.12 mm vs. 0.41±0.10 mm, p=0.001) than those with ≤5 mm advancement. Multivariate linear regression confirmed that greater magnitude of advancement was an independent negative predictor of percentage relapse (p=0.033). Concomitant mandibular surgery, age, and sex did not significantly affect the stability.

Conclusion

Four-point 2.0-mm titanium miniplate fixation provided reliable long-term skeletal stability after LeFort I maxillary advancement. Larger advancements were more stable than smaller ones, supporting adequate rather than conservative surgical correction. Clinicians can counsel patients that approximately one-quarter of the achieved advancement is typically lost within the first postoperative year with excellent stability thereafter.