Accuracy Of Orthognathic Surgery Research Articles

Do Patient-Specific Osteosynthesis Plates Improve Accuracy in Orthognathic Surgery?

Do Patient-Specific Osteosynthesis Plates Improve Accuracy in Orthognathic Surgery?

Evaluation of the Predictability and Accuracy of Orthognathic Surgery in the Era of Virtual Surgical Planning

Virtual surgical planning allows orthognathic surgeons to design a surgical plan preoperatively and establish a personalized surgical protocol. This study aims to validate the predictability and accuracy of orthognathic surgery through a comparison of the three-dimensional (3D) models of the virtual planning and postoperative CBCT using free software (3D Slicer) on 40 patients who underwent bimaxillary orthognathic surgery. The distances of point A, point B, pogonion (Pog), and the first upper and lower molars, both in each axis (x, y, and z) and in the 3D space, were analyzed. The median of the distances in the mediolateral direction was the lowest, while the highest differences were found at point A and Pog in the anteroposterior direction (0.83 mm and 0.78 mm, respectively). Vertical differences were higher in the maxilla than in the mandible. In conclusion, we found that orthognathic bimaxillary surgery using virtual surgical planning was more accurate when positioning the bone segments in the mediolateral direction, using the information provided by the splint, as well as when positioning the mandible compared to the maxilla.

Virtually-Planned Orthognathic Surgery Achieves an Accurate Condylar Position

Accuracy in orthognathic surgery with virtual planning has been reported, but detailed analysis of accuracy according to anatomic location, including the mandibular condyle, is insufficient. The purpose of this study was to compare the virtual plan and surgical outcomes and analyze the degree and distribution of errors according to each anatomic location. This retrospective cohort study evaluated skeletal class III patients, treated with bimaxillary surgery. The primary predictor was anatomic locations that consisted of right and left condyles, maxilla, and the distal segment of the mandible. Other variables were age and gender. The primary outcome was surgical accuracy, defined as mean 3-dimensional distance error, mean absolute error, and mean error along the horizontal, vertical, and anteroposterior axes between the virtual plan and surgical outcomes. Landmarks were compared using a computational method based on affine transformation with a 1-time landmark setting. The mean errors were visualized with multidimensional scattergrams. Bivariate and regression statistics were computed. This study included 52 patients, 26 men and 26 women, with a mean age of 21years and 3months. The mean 3D distance errors for condylar landmarks, maxillary landmarks, and landmarks on the distal segment of the mandible were 1.03, 1.25, and 2.24mm, respectively. Condylar landmarks, maxillary landmarks, and the landmarks on the distal segment of the mandible were positioned at 0.49mm inferior, 0.28mm anterior, and 1.25mm inferior, respectively. The landmark errors for the distal segment of the mandible exhibited a wider distribution than those for condylar and maxillary landmarks. Agreement between the planned and actual outcome aided by virtual surgical planning was highest for the condyles, followed by the maxilla, and the distal segment of the mandible. It is important to consider the tendency for surgical errors in each anatomic location during operations.

“Monoblock” Occlusal Model to Enhance Occlusal Verification During Orthognathic Surgery

Intraoperative verification of the planned occlusion is critical in ensuring the accuracy of orthognathic surgery. This step is limited to visual inspection, which can be especially challenging when the planned occlusal setup is less-than-stable. The authors introduce a cost-effective method of an accurate reproduction of the planned occlusion using additive manufacturing which can aid in intraoperative verification of positionally unstable occlusal setups. The authors present a case example, and discuss various technical considerations.

Splintless surgery using patient-specific osteosynthesis in Le Fort I osteotomies: a randomized controlled multi-centre trial

The accuracy of orthognathic surgery has improved with three-dimensional virtual planning. The translation of the planning to the surgical result is reported to vary by >2mm. The aim of this randomized controlled multi-centre trial was to determine whether the use of splintless patient-specific osteosynthesis can improve the accuracy of maxillary translation. Patients requiring a Le Fort I osteotomy were included in the trial. The intervention group was treated using patient-specific osteosynthesis and the control group with conventional osteosynthesis and splint-based positioning. Fifty-eight patients completed the study protocol, 27 in the patient-specific osteosynthesis group and 31 in the control group. The per protocol median anteroposterior deviation was found to be 1.05mm (interquartile range (IQR) 0.45–2.72mm) in the patient-specific osteosynthesis group and 1.74mm (IQR 1.02–3.02mm) in the control group. The cranial–caudal deviation was 0.87mm (IQR 0.49–1.44mm) and 0.98mm (IQR 0.28–2.10mm), respectively, whereas the left–right translation deviation was 0.46mm (IQR 0.19–0.96mm) in the patient-specific osteosynthesis group and 1.07mm (IQR 0.62–1.55mm) in the control group. The splintless patient-specific osteosynthesis method improves the accuracy of maxillary translations in orthognathic surgery and is clinically relevant for planned anteroposterior translations of more than 3.70mm.

Accuracy between virtual surgical planning and actual outcomes in orthognathic surgery by iterative closest point algorithm and color maps: A retrospective cohort study.

BackgroundTo evaluate the accuracy between actual outcomes and virtual surgical planning (VSP) in orthognathic surgery regarding the use of three-dimensional (3D) surface models for registration using iterative closest point (ICP) algorithm and generated color maps.Material and MethodsConstruction of planning and postoperative 3D models in STL files format (M0 and M1, respectively) from CBCT of 25 subjects who had been submitted to bimaxillary orthognathic surgery was performed. M0 and M1 were sent to Geomagic software in semi-automatic alignment surface mesh order of M0 and M1 for registration using ICP algorithm to calculate mean deviation (MD, MD+, MD-, SD) and root mean square (RMS – 3D Error). Color maps were generated to assess qualitative congruence between M0 and M1. From deviation analysis, 3D Error was defined as accuracy measurement. To assess the reproducibility, the workflow was performed by two evaluators multiple times. t-tests were used to assess whether all means of MD, MD+, MD-, SD and 3D Error values would be ≤ - 2 mm and ≥ 2 mm.ResultsHigh intra and inter evaluators correlation were found, supporting the reproducibility of the workflow. t-tests proved that all MDs and 3D Error values were > - 2 mm and < 2 mm.Conclusions3D error mean was within the standards of clinical success lower than 2 mm. ICP algorithm provided a reproducible method of alignment between 3D models and generated color maps to evaluate 3D congruence but did not answer all methodological parameters regarding the assessment of accuracy in orthognathic surgery. Key words:Accuracy, Cone-Beam computed tomography, CAD-CAM, Orthognathic surgery, three-dimensional imaging.

Accuracy in orthognathic surgery─comparison of preoperative plan and postoperative outcome using computer-assisted two-dimensional cephalometry by the Onyx Ceph® system

PurposeThis retrospective study analyzes deviations between preoperative planning and postoperative outcome in orthognathic surgery using 2D Onyx Ceph®-cephalometric analyzing and planning system. Materials and methodsA total of 100 patients with a mean age 25.1 of years were included in this study. In 33 patients a bilateral sagittal split osteotomy and in seven patients a Le Fort I osteotomy was performed. A total of 60 patients were treated by a bimaxillary approach. Onyx Ceph® was used as cephalometric planning software (Onyx Ceph®), followed by mock operations. Postoperative cephalograms were obtained after 3.3 days and compared to preoperative planning cephalograms for sagittal (SNA, SNB, ANB) and vertical (ArGoMe, ML-NSL, NL-NSL) angle measurements. Real and absolute mean deviation were documented. ResultsAbsolute mean deviation (degrees) between postoperative and planned jaw movement was lower for the sagittal parameters SNA (0.58), SNB (1.15) and ANB (1.05) compared to the vertical parameters NL-NSL (1.47), ML-NSL (1.96) and ArGoMe (3.20). SNA, SNB and ANB showed constant deviations independent from the extent of jaw movement. With regard to the vertical parameters ML-NSL, ArGoMe and NL-NSL the extent of the postoperative rotational jaw movement was not as much as planned, particularly for vertical shifts of more than 4°. ConclusionBy using the 2D Onyx Ceph® cephalometric software for orthognathic surgery, the deviations between planned and actual movements are within an acceptable and predictable range. Planning of extensive vertical alterations may result in greater deviations after surgery.

Accuracy of orthognathic surgery using 3D computer-assisted surgical simulation

Abstract Objective To evaluate the accuracy of maxilla and mandibular repositioning during two-jaw orthognathic surgery using computerassisted surgical simulation (CASS) Materials and methods Fifteen patients who underwent two-jaw orthognathic surgery using CASS (VSP,® Orthognathics by 3D Systems) were evaluated to assess the accuracy of the simulation. Translational and rotational discrepancies of the centroids of the maxilla and mandible and the translational discrepancy of the dental midline between the planned and actual outcomes were reported using the root mean square error (RMSE). The number of cases that exceeded limits set for clinical significance, the direction of the error in relation to the direction of planned movement and the differences between segmental and non-segmental procedures were evaluated as secondary outcomes Results The largest translational RMSE was 1.53 mm along the y-axis in the maxilla and 1.34 mm along the y-axis in the mandible. The largest rotational RMSE was 1.9° about the x-axis in the maxilla and 1.16° about the x- and y-axes in the mandible. The largest RMSE for the dental midline was 1.6 mm along the y-axis in the maxilla and 1.34 mm along the y-axis in the mandible. A tendency for insufficient advancement of the maxilla was noted Conclusions CASS is an efficient and accurate way to develop the surgical plan and transfer the plan to the patient intraoperatively. While CASS is accurate on a population level, there remains the potential for clinically significant errors to occur on an individual basis Conclusion The present case indicated that the timely extraction of palatally-placed maxillary lateral incisors facilitated functional appliance therapy in the management of a skeletal Class II problem. The crowding of the lower anterior teeth was relieved and alignment of the upper arch was achieved with full fixed appliance therapy, resulting in improved aesthetics and a stable occlusion at one year review

Accuracy of orthognathic surgery — a retrospective service evaluation

Accuracy of orthognathic surgery — a retrospective service evaluation

Custom-Machined Miniplates and Bone-Supported Guides for Orthognathic Surgery: A New Surgical Procedure

Several surgical strategies exist to improve accuracy in orthognathic surgery, but ideal planning and treatment have yet to be described. The purpose of this study was to present and assess the accuracy of a virtual orthognathic positioning system (OPS), based on the use of bone-supported guides for placement of custom, highly rigid, machined titanium miniplates produced using computer-aided design and computer-aided manufacturing technology. An institutional review board-approved prospective observational study was designed to evaluate our early experience with the OPS. The inclusion criteria were as follows: adult patients who were classified as skeletal Class II or III patients and as candidates for orthognathic surgery or who were candidates for maxillomandibular advancement as a treatment for obstructive sleep apnea. Reverse planning with computed tomography and modeling software was performed. Our OPS was designed to avoid the use of intermaxillary fixation and occlusal splints. The minimum follow-up period was 1year. Six patients were enrolled in the study. The custom OPS miniplates fit perfectly with the anterior buttress of the maxilla and the mandible body surface intraoperatively. To evaluate accuracy, the postoperative 3-dimensional reconstructed computed tomography image and the presurgical plan were compared. In the maxillary fragments that underwent less than 6mm of advancement, the OPS enabled an SD of 0.14mm (92% within 1mm) at the upper maxilla and 0.34mm (86% within 1mm) at the mandible. In the case of great advancements of more than 10mm, the SD was 1.33mm (66% within 1mm) at the upper maxilla and 0.67mm (73% within 1mm) at the mandibular level. Our novel OPS was safe and well tolerated, providing positional control with considerable surgical accuracy. The OPS simplified surgery by being independent of support from the opposite maxilla and obviating the need for classic intermaxillary occlusal splints.

Checking the prediction accuracy in orthognathic surgery

Checking the prediction accuracy in orthognathic surgery

Improving the Accuracy of Orthognathic Surgery Through the Use of the Tridimensional Orthognathic Gauge™

Improving the Accuracy of Orthognathic Surgery Through the Use of the Tridimensional Orthognathic Gauge™

A Mix-resolution Bone-related Statistical Deformable Model (mBr-SDM) for Soft Tissue Prediction in Orthognathic Surgery Planning

In this paper, we propose a Mix-resolution Bone-related Statistical Deformable Model (mBr-SDM) to improve the predicting accuracy of orthognathic surgery, particularly for the main deformation region. Mix-resolution Br-SDM consists of two separate Br-SDM of different resolutions: a high-resolution Br-SDM which is trained with more samples to capture the detail deforming variations in the main deforming regions of interest, together with a low-resolution Br-SDM which is trained with a smaller number of samples to capture the major variations of the remaining facial points. The experiments have shown that the mix-resolution Br-SDM is able to significantly reduce the predicting error compared with the corresponding Finite Element Model, while giving a low computational cost which is characteristic of the SDM approach.

Rapid Maxillary Distraction Protocol Utilizing the Halo Distraction System and Rigid Internal Fixation

To shorten head frame wear time associated with external halo distraction (HD), we have adapted a protocol for maxillary distraction with the halo system that integrates plate fixation. All patients had a history of cleft lip and/or palate and maxillary retrusion > or = 8 mm. Five patients treated with this protocol and followed for at least 1 year were included in this study. The protocol included a 3-day latency period, variable maxillary distraction, and removal of the halo device with simultaneous rigid internal fixation. Two patients had a variable period of maxillomandibular fixation (MMF), which maintained the maxillary advancement and idealized intercuspal position while permitting further callus maturation. Cephalographs were obtained preoperatively, immediately following distractor removal, and 1 year after rigid internal fixation. The mean age at time of surgery was 18.7 years. The maxillary deficiency ranged from 8 to 15 mm (mean = 10.6 mm). All five patients demonstrated excellent occlusion. Cephalometric analysis 1-year post rigid internal fixation revealed minimal (<1 mm) skeletal relapse. Rapid maxillary distraction followed by MMF to maintain maxillary advancement may reduce halo device wear to 1 to 2 weeks. MMF optimizes occlusion by forcing the maxillary teeth into maximal intercuspal position. Rigid fixation is not only associated with less long-term relapse compared to nonrigid forms of fixation, but also minimizes the incidence of nonunion. This treatment protocol provides the advancement possible with distraction osteogenesis and the accuracy of orthognathic surgery, thereby minimizing external head frame wear.

Polyvinylsiloxane as an Alternative Material for the Intermediate Orthognathic Occlusal Splint

Accuracy in orthognathic surgery is dependent on a number of factors. First, meticulous preoperative evaluation including a critical clinical examination, dental models, face-bow, and occlusal registrations, is paramount in preparation for orthognathic surgery. The second step in the process is the accurate application of this data to the orthognathic model surgery, which in turn leads to the fabrication of accurate surgical splints. Finally, application of these splints, coupled with sound surgical technique, allows accurate positioning of the jaws at the time of surgery.

Surgical accuracy in orthognathic surgery

This study investigated the accuracy with which the planned surgical change could be achieved during orthognathic surgery, based upon the retrospective cephalometric analysis of 62 patients who received correction of dentofacial deformity. It is concluded that, despite individual variation, no statistically significant difference could be demonstrated between the orthognathic prediction and the surgical outcome. This supports both the use of orthognathic profile planning and the surgeon's ability to follow the plan.