Predictability of maxillary repositioning during bimaxillary surgery: accuracy of a new technique

doi:10.1016/j.ijom.2006.10.015

International Journal of Oral and Maxillofacial Surgery

Volume 36, Issue 4, April 2007, Pages 296-300

https://doi.org/10.1016/j.ijom.2006.10.015 Get rights and content

Abstract

The purpose of this retrospective study was to evaluate the predictability of maxillary repositioning following Le Fort I osteotomy during bimaxillary surgery using a new technique with splints to reposition the maxilla in the three planes of space. In order to assess the accuracy of horizontal and vertical maxillary movements of the maxilla, 32 consecutive patients who underwent bimaxillary surgery had their predictive tracings and model surgery measures compared to postoperative cephalograms taken 1 week after surgery. There was a strong positive correlation between model surgery and postoperative result: 53% of horizontal movements and 41% of vertical movements showed less than 0.2 mm variation. When predictive tracings were compared to postoperative results 44% of horizontal and 50% of vertical movements showed less than 0.2 mm variation. There was no significant difference (P > 0.05) between the planned and actual maxillary positions in the sample evaluated. This technique for maxillary repositioning during two-jaw surgery proved to be effective and predictable, with strong agreement between predictive tracings, model surgery and postoperative results.

Section snippets

Material and methods

Thirty-two consecutive patients who underwent bimaxillary surgery during a 9-month period were included in this study. Inclusion criteria were complete pre- and postoperative cephalometric documentation, predictive tracings, model surgery casts and hospital records with planned movements of maxillary surgery, a one-piece Le Fort I osteotomy in any direction, absence of craniofacial anomalies or cleft lip/palate, and no previous maxillary surgery.

Results

The variability between the planned maxillary position in model surgery and the post-surgical position in the horizontal and vertical plane is presented in Table 1. The majority of cases showed a variation of less than 0.2 mm for either horizontal or vertical movement. Only one case presented a variation of 0.7 mm. Figure 4 shows graphs of the planned horizontal and vertical position of the upper incisor in model surgery versus the postoperative result.

The variability between the planned

Discussion

Since orthognathic surgery is elective, it is imperative that the surgeon strives to provide the patient with the most accurate surgical repositioning possible⁹. Esthetic demands nowadays determine successful parameters, and a few millimetres of inaccuracy of the upper incisive position can affect patient satisfaction, mainly in the vertical position.

The accuracy of orthognathic surgery depends on two main steps: paper surgery to model surgery and model surgery to real surgery. Before surgery,

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Cited by (49)

Comparison of the Accuracy of Maxillary Repositioning Between Using Splints and Templates in 2-Jaw Orthognathic Surgery
2022, Journal of Oral and Maxillofacial Surgery
Printed cutting and repositioning templates could bring superior accuracy when transferring a maxillary plan to the operating room compared to a wafer-based method. However, the effect of these methods in different types of cases is inconclusive. The objective of the study was to compare the accuracy when using printed occlusal splints versus templates in simple and complicated cases.
A retrospective cohort study design was used. Complicated cases were defined as cases involving impaction movement of more than 2 mm, occlusal plane canting of more than 3°, or midline discrepancies of more than 2.5 mm. Other cases were simple cases. Enrolled patients were randomly allocated into the digital occlusal splint (DOS) cohort and the digital templates (DT) cohort. The outcome variable was surgical accuracy, defined as the average deviation between the planned and postsurgical locations of bilateral maxillary central incisors, canines, first premolars, and first molars. Predictor variables were 1) operative complexity, simple versus complicated; and 2) technique for positioning the maxilla, DOS versus DT. Covariates were age and planned surgical movement. Two-way analysis of variance was used.
Seventy patients were included in this study. Thirty-three were in the DOS cohort, and 37 in the DT cohort. The average deviation was significantly smaller in the complicated cases in the DT cohort (1.37 mm; 95% confidence interval, 1.08-1.66 mm) than that in the DOS cohort (2.47 mm; 95% confidence interval, 1.92-3.02 mm) (P = .002). The deviations in anteroposterior direction of complicated cases in the DT cohort were smaller than the corresponding values of the DOS cohort (P = .035). There is no significant difference between the deviation values of simple and complicated cases using templates (P = .116).
These results indicate that in complicated cases, printed guiding templates exhibit better accuracy for repositioning the maxilla than printed occlusal splints, and the effect of templates in different cases proved to be stable.
Accuracy of midface advancement using patient-specific surgical guides and pre-bent plates versus conventional interocclusal wafers and conventional plate fixation in quadrangular Le Forte II osteotomy. A randomised controlled trial
2021, British Journal of Oral and Maxillofacial Surgery
The aim of this study was to assess the accuracy of quadrangular Le Fort II osteotomy and midface advancement utilising digitally fabricated surgical guides with pre-bent plates compared with conventional interocclusal wafers. Twenty patients with midface deficiency were allocated randomly to two groups: patient-specific surgical guides and pre-bent titanium miniplates were utilised in the study group, while conventional interocclusal wafers with intraoperatively adapted titanium miniplates were utilised in the control group. The accuracy of virtual planning was assessed in both groups using computed tomography (CT). Both groups showed accurate transfer of the plan, but the computer-guided group showed significantly greater accuracy and a shorter surgical time than the conventional group. The use of patient-specific surgical guides and pre-bent plates represents a promising computer-guided approach especially for inexperienced surgeons. Nevertheless, a major limitation is increased overall cost compared with the conventional approach.
Comparison of three different types of splints and templates for maxilla repositioning in bimaxillary orthognathic surgery: a randomized controlled trial
2021, International Journal of Oral and Maxillofacial Surgery
The selection and implementation of a plan for maxillary surgery is of the utmost importance in achieving the desired outcome for the patient undergoing two-jaw orthognathic surgery. Some splint-based and splintless methods, accompanied by computer-assisted techniques, are helpful in improving surgical plan implementation. However, randomized controlled trials focused on this procedure are lacking. This study included 61 patients who underwent bimaxillary surgeries. The patients were randomly assigned to a conventional resin occlusal splint (CROS) group, a digital occlusal splint (DOS) group, or a digital templates (DT) group, in a 1:1:1 ratio. The mean linear distance between the planned and actual postoperative positions of eight selected points on the surfaces of the maxillary teeth was selected as the outcome measure. The distance was significantly smaller in the DT group (1.17 ± 0.66 mm) when compared to both the CROS group (2.55 ± 0.95 mm, P < 0.05) and DOS group (2.15 ± 1.12 mm, P < 0.05). However, the difference between the CROS group and DOS group was not statistically significant. These findings indicate that using digital templates results in the best performance in transferring the surgical plan to the operation environment as compared to the other two types of splints. This suggests that the application of digital templates could provide a reliable treatment option.
Treatment of hemimandibular hyperplasia by computer-aided design and computer-aided manufacturing cutting and drilling guides accompanied with pre-bent titanium plates
2020, Journal of Cranio-Maxillofacial Surgery
The treatment of hemimandibular hyperplasia (HH) is difficult by performing condylectomy and orthognathic surgery in one stage. This study investigated the clinical feasibility of treating HH with computer-aided design and computer-aided manufacturing (CAD/CAM) cutting and drilling guides and the pre-bent titanium plates to improve the accuracy of operation to avoid condyle reconstruction.
12 patients diagnosed with HH were included in this study from 2014 to 2018. Conservative condylectomy and bimaxillary orthognathic surgery were performed in all patients. The CAD/CAM cutting and drilling guides and the pre-bent titanium plates were used to guide surgeries. Follow-up and radiographic examinations were performed. The difference between virtually simulated and postoperative models was measured.
All patients got satisfactory and stable results, without complications or obvious relapse during follow-up. Occlusion relationship, temporomandibular joint function and facial symmetry were improved obviously after surgery. Comparison between simulated plans and actual postoperative outcomes showed that the surgical plans were transferred accurately.
CAD/CAM cutting and drilling guides and the pre-bent titanium plates described in this paper can help transferring the results from computer simulation to the operating room accurately. Conservative condylectomy can be operated exactly matching bimaxillary orthognathic surgery for treating HH, avoiding condyle reconstruction.
Three-dimensional measurement and registration accuracy of a third-generation optical tracking system for navigational maxillary orthognathic surgery
2019, Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology
The purpose of this study was to evaluate the accuracy of an optical tracking system during reference point localization, measurement, and registration of skull models for navigational maxillary orthognathic surgery.
Accuracy was first evaluated on the basis of the position recording discrepancy at a static point and at 2 points of fixed lengths. Ten reference points were measured on a skull model at 7 different locations, and their measurements were compared with predicted positions by using 4 registration methods. Finally, positional tracking of reference points for simulated maxillary surgery was performed and compared with laser scan data.
The average linear measurement discrepancy was 0.28 mm, and the mean measurement discrepancy with the 5 registered cranial points was 1.53 mm. The average measurement discrepancy after maxillary surgery was 1.91 mm (for impaction) and 1.56 mm (for advancement). The registration discrepancy in jitter and point registration on the y-axis was significantly greater than on the other axes.
The optical tracking system seems clinically acceptable for precise tracking of the maxillary position during navigational orthognathic surgery, notwithstanding the chance of greater measurement error on the y-axis.
Influence of the anatomical form of the posterior maxilla on the reliability of superior maxillary repositioning by Le Fort I osteotomy
2019, International Journal of Oral and Maxillofacial Surgery
Certain patients with facial deformities require superior repositioning of the maxilla via Le Fort I osteotomy; however, the magnitude of superior repositioning of the maxilla is often less than expected. In this study, the correlation between the accuracy of superior repositioning of the maxilla and the anatomical form of the maxillary posterior region was examined. Seventy-five patients who underwent Le Fort I osteotomy without forward movement of the maxilla but with superior repositioning of the maxilla were included in this study. The bone volume around the descending palatine artery (DPA), the angle of the junction between the pterygoid process and the tuberosity, and the distance between the upper second molar and the pterygoid process were measured via three-dimensional analysis. A significant negative correlation (r = −0.566) was found between the bone volume around the DPA and the ratio of repositioning (actual movement divided by expected movement). It is possible that the superior repositioning of the maxilla expected prior to surgery was not sufficiently attained because of the large volume of bone around the DPA. The results of this study show that in some patients, superior repositioning was not achieved at the expected level because of bone interference attributable to the anatomical form of the maxillary posterior region.

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Clinical PaperOrthognathic SurgeryPredictability of maxillary repositioning during bimaxillary surgery: accuracy of a new technique

Abstract

Section snippets

Material and methods

Results

Discussion

Br J Oral Maxillofac Surg

J Oral Maxillofac Surg

J Oral Maxillofac Surg

J Oral Maxillofac Surg

Int J Oral Maxillofac Surg

J Oral Maxillofac Surg

Clinical Paper
Orthognathic Surgery
Predictability of maxillary repositioning during bimaxillary surgery: accuracy of a new technique