Influence of the anatomical form of the posterior maxilla on the reliability of superior maxillary repositioning by Le Fort I osteotomy

U-Shaped Osseous Release for Le Fort 1 Osteotomy: Potential Application to Superior Repositioning

This study was performed to investigate the utility of U-shaped osseous release (USOR) for Le Fort 1 osteotomy as a novel surgical technique for superior repositioning. Thirty-six patients with jaw deformities were divided into 2 groups based on whether or not USOR was adopted (18 in the non-adoption group and 18 in the adoption group). Maxillary surgical time, blood loss, and discrepancy from the planned amount of movement (anterior-posterior and superior-inferior directions) were compared between the 2 groups. Correlations between these items and the planned amount of superior-inferior movement were also examined. There were no significant differences in mean age, preset displacement, surgical time, blood loss, body mass index, or preset displacement error. However, a significant positive correlation was observed between the planned and actual amount of vertical movement only in the adoption group ( P =0.0018). In addition, there was a tendency for the error (downward) to increase as the amount of upward movement increased in the non-adoption group, but not the adoption group. These findings suggest that USOR may be a useful technique because it can safely and conveniently remove bony interference and can enable guidance to a more precise position, especially in cases with substantial superior movement.

Assessment of Maxillary Sinus Variations Post-LeFort: A Systematic Review

Background

The purpose of this article was to systematically review maxillary sinus changes after LeFort. We examined and analyzed the anatomical abnormalities that occurred following LeFort I osteotomy, as well as the abnormalities of maxillary sinus volume (MSV) before and after the operation.

Methods

A systematic search was conducted on various databases, such as Google Scholar, PubMed, and Scopus. The articles used were in English and original. This study was conducted until September 2023, and after reviewing the articles, several keywords, such as "Maxillary sinus" and "LeFort I osteotomy", were employed. The obtained data were evaluated based on the PICO framework.

Results

Findings from 15 studies showed that the amount of MSV decreased before and after the operation (considering the three dimensions of the sinus, the measurement was performed linearly). These reduction values differed between men and women, with men having a greater reduction. As is the case with other operations, there were some side effects associated with this type of operation that some patients experienced postoperatively.

Conclusion

In both male and female patients, the MSV was reduced after one-piece and multi-segment osteotomies. Nonetheless, one-piece LeFort I osteotomy showed a higher reduction in MSV than the multi-segment osteotomy method, according to this systematic review and meta-analysis.

Accuracy of mandible-independent maxillary repositioning using pre-bent locking plates: a pilot study

The double splint method is considered the gold standard for maxillary repositioning, but the procedure is lengthy and prone to error. Recent splintless methods have shown high repositioning accuracy; however, high costs and technical demands make them inaccessible to many patients. Therefore, a new cost-effective method of mandible-independent maxillary repositioning using pre-bent locking plates is proposed. Plates are bent on maxillary models in the planned position prior to surgery. The locations of the plate holes are replicated during surgery using osteotomy guides made from thermoplastic resin sheets. Pre-bent plates are subsequently fitted onto the maxilla, and plate holes are properly set to reposition the maxilla. The purpose of this study was to evaluate the accuracy of this method for maxillary repositioning and the reproducibility of the plate holes. Fifteen orthognathic surgery patients were evaluated retrospectively by superimposing preoperative simulations over their postoperative computed tomography models. The median deviations in maxillary repositioning and plate hole positioning between the preoperative plan and postoperative results were 0.43mm (range 0-1.55mm) and 0.33mm (range 0-1.86mm), respectively. There was no significant correlation between these deviations, suggesting that the method presented here allows highly accurate and reliable mandible-independent maxillary repositioning.