# 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.

## Key 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.