Computer-assisted orthognathic surgery: feasibility study using multiple CAD/CAM surgical splints

doi:10.1016/j.oooo.2011.11.009

Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology

Volume 113, Issue 5, May 2012, Pages 673-687

https://doi.org/10.1016/j.oooo.2011.11.009 Get rights and content

Objective

We present a virtual planning protocol incorporating a patented 3–surgical splint technique for orthognathic surgery. The purpose of this investigation was to demonstrate the feasibility and validity of the method in vivo.

Materials and Methods

The protocol consisted of (1) computed tomography (CT) or cone-beam computed tomography (CBCT) maxillofacial imaging, optical scan of articulated dental study models, segmentation, and fusion; (2) diagnosis and virtual treatment planning; (3) computed-assisted design and manufacture (CAD/CAM) of the surgical splints; and (4) intraoperative surgical transfer. Validation of the accuracy of the technique was investigated by applying the protocol to 8 adult class III patients treated with bimaxillary osteotomies. The virtual plan was compared with the postoperative surgical result using image fusion of CT/CBCT dataset by analysis of measurements between hard and soft tissue landmarks relative to reference planes.

Results

The virtual planning approach showed clinically acceptable precision for the position of the maxilla (<0.23 mm) and condyle (<0.19 mm), marginal precision for the mandible (<0.33 mm), and low precision for the soft tissue (<2.52 mm).

Conclusions

Virtual diagnosis, planning, and use of a patented CAD/CAM surgical splint technique provides a reliable method that may offer an alternate approach to the use of arbitrary splints and 2-dimensional planning.

Section snippets

Computer-Assisted Orthognathic Surgery: Virtual Planning and CAD/CAM Surgical Splints

We have developed and patented (WO 2008/031562) a computer-assisted design and manufacture (CAD/CAM) technique for the fabrication of multiple surgical splints for orthognathic surgery.³¹ The benefits of this technique are that it allows direct operative transfer of virtual surgical plans, and is easy to use, relatively inexpensive, and clinically efficient. The workflow process consists of 4 stages as described in the following paragraphs.

Sample

This was a prospective observational design approved by the Ethics Committee of the Medical Faculty of the University of Cologne (approval no. 05-111). Subjects were recruited from patients who attended the University Clinic in Cologne. All patients were provided with informed consent. The inclusion criteria were (1) adult patients, (2) skeletal class III, (3) dental class III combined with an open bite or vertical maxillary extrusion, and (4) consented to bimaxillary surgeries. The exclusion

Results

Both mean intra- (0.91) and interobserver (0.92) ICC reliabilities were high. All correlations were highly significant (P < .0001).

Table IV shows the angular measurement differences between virtual planning position (T0) and postoperative surgical result (T1) in relation to various reference planes. The inclination of the angles between the maxillary and occlusal planes between the FHP and the midfacial plane showed no significant differences (ΔT1 – T0). Although mean angular differences for

Discussion

In this article, we presented a computer-assisted orthognathic surgery protocol incorporating a patented CAD/CAM 3-splint concept. We showed that this approach provided clinically acceptable precise transfer of preoperative planning to the surgical environment for the maxilla (<0.23 mm) and the condyles (<0.05°, <0.18 mm), comparing favorably with reported variations within conventional clinical orthognathic protocols incorporating lateral cephalometry, facebow transfer to a semiadjustable

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Enhancing skeletal stability and Class III correction through active orthodontist engagement in virtual surgical planning: A voxel-based 3-dimensional analysis
2024, American Journal of Orthodontics and Dentofacial Orthopedics
Skeletal stability after bimaxillary surgical correction of Class III malocclusion was investigated through a qualitative and quantitative analysis of the maxilla and the distal and proximal mandibular segments using a 3-dimensional voxel-based superimposition among virtual surgical predictions performed by the orthodontist in close communication with the maxillofacial surgeon and 12-18 months postoperative outcomes.
A comprehensive secondary data analysis was conducted on deidentified preoperative (1 month before surgery [T1]) and 12-18 months postoperative (midterm [T2]) cone-beam computed tomography scans, along with virtual surgical planning (VSP) data obtained by Dolphin Imaging software. The sample for the study consisted of 17 patients (mean age, 24.8 ± 3.5 years). Using 3D Slicer software, automated tools based on deep-learning approaches were used for cone-beam computed tomography orientation, registration, bone segmentation, and landmark identification. Colormaps were generated for qualitative analysis, whereas linear and angular differences between the planned (T1-VSP) and observed (T1-T2) outcomes were calculated for quantitative assessments. Statistical analysis was conducted with a significance level of α = 0.05.
The midterm surgical outcomes revealed a slight but significantly less maxillary advancement compared with the planned position (mean difference, 1.84 ± 1.50 mm; P = 0.004). The repositioning of the mandibular distal segment was stable, with insignificant differences in linear (T1-VSP, 1.01 ± 3.66 mm; T1-T2, 0.32 ± 4.17 mm) and angular (T1-VSP, 1.53° ± 1.60°; T1-T2, 1.54° ± 1.50°) displacements (P >0.05). The proximal segments exhibited lateral displacement within 1.5° for both the mandibular right and left ramus at T1-VSP and T1-T2 (P >0.05).
The analysis of fully digital planned and surgically repositioned maxilla and mandible revealed excellent precision. In the midterm surgical outcomes of maxillary advancement, a minor deviation from the planned anterior movement was observed.
Do Patients Detect Changes in Breathing After Orthognathic Surgery?
2024, Journal of Oral and Maxillofacial Surgery
Orthognathic surgery addresses facial aesthetics and function in patients with dentofacial deformities. It is associated with changes in upper airway volume (UAV). If changes in UAV are perceived by asymptomatic patients is unclear.
The purpose was to measure associations between changes in UAV and patient-reported benefits using patient-reported outcome measures.
A sample presenting dentofacial deformities without reported breathing problems undergoing orthognathic surgery was retrospectively studied. Patients aged 18-30 years with 12-month follow-up were included. Patients with systemic disease, drug abuse, mental health disorder, or temporomandibular joint dysfunction were excluded.
The predictor variable was changes in UAV measured in 3-dimensional computed tomography. Subjects were grouped into increased or decreased UAV.
The primary outcome variable was changes in health-related quality of life measured with Oral Health Impact Profile 49 (OHIP-49).
Weight, height, age, sex, and sub-scaled OHIP-49 were registered. Cephalometric measurements of hard tissue movements were recorded.
Mean, standard deviation, and a level of statistical significance at P < .05 were used. Differences in OHIP-49 were compared using unpaired t-test. The correlation between covariates and outcomes was analyzed using the Spearman’s rank test. Analysis of covariance between the predictor and outcome, adjusted for covariates (body mass index), was performed.
Fifty-four subjects with a mean age of 20.89 years and 52% males were enrolled. The mean change in UAV was 0.12 cm³ (standard deviation [SD] 9.21, P = .93) with a mean absolute deviation of 7.28 cm³ (SD 5.54). The mean change in OHIP-49 score was 20.93 (SD 28.90). Twenty-seven (50%) subjects had increased UAV (7.4 cm³, SD 6.13) and the other had decreased (−7.17 cm³, SD 5.01) (P = .01). At follow-up, equal levels of mean OHIP-49 score were found, but because of a baseline difference (15.74, P = .048), the subjects with and without increased UAV improved in OHIP-49 score 13.04 (SD 30.53) and 28.81 (SD 25.33), respectively (P = .04).
Because equal levels of OHIP-49 score at follow-up, changes in UAV could not be associated with patient-reported health-related quality of life. Patient-reported outcome measure evaluations of orthognathic surgical treatment for airway obstruction should be performed in patients with a perceived impairment.
Patient-specific plates for facial fracture surgery: A retrospective case series
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Surgeons often encounter challenges when treating maxillofacial fractures using conventional methods that involve trimming or bending ready-made titanium plates for open reduction and internal fixation (ORIF) since it can be time-consuming, imprecise, and inconvenient. This retrospective case series aimed to introduce a novel bone reduction method that utilizes virtual planning, patient-specific surgical guides, and titanium plates.
Seven patients with mandibular symphysis or subcondylar fractures resulting from facial trauma underwent cone-beam computed tomography (CBCT) or facial CT scans, and their medical histories were documented. Virtual surgery was conducted based on three-dimensional (3D) stereolithography images derived from CT scans using the FaceGide software (MegaGen, Daegu, Korea). ORIF was performed using patient-specific surgical guides and plates that were designed, printed, and milled. Radiographic, clinical, and occlusal evaluations were conducted at two weeks and six weeks postoperatively. Subsequently, 3D images from virtual surgery and postoperative CT scans were compared.
The comparison of 3D virtual surgery and postoperative images revealed minimal surface differences of less than 1 mm. T-scan evaluations indicated that there were no statistically significant differences between the two- and six-week postoperative assessments. Favorable clinical outcomes were observed.
This novel method demonstrated stable outcomes in terms of occlusion and healing, with no notable complications. Consequently, this approach may serve as a viable alternative to conventional methods.
Facial fracture surgery that utilizes patient-specific surgical guides and plates within a digital workflow can facilitate meticulous surgical planning, reducing the risk of complications and minimizing operation time.
Custom made cutting guides and osteosynthesis plates versus CAD/CAM occlusal splints in positioning and fixation of the maxilla in orthognathic surgery: A prospective randomized study
2022, Journal of Cranio-Maxillofacial Surgery
The aim of this study is to compare the accuracy of maxilla positioning in orthognathic surgery with the use of custom-made devices (cutting guides and patient-fitted osteosynthesis plates) comparing to CAD/CAM splints.
A prospective randomized study was performed. Patients with dentofacial deformities undergoing orthognathic surgery were compared, using customized guides (experimental group) vs. CAD/CAM surgical splints (control group) for the repositioning of the upper maxilla. Preoperative and postoperative CT scans were used to compare positioning and fixation of the maxilla in the three planes of space.
A total of 30 patients were included in the study (15 patients in each study group). The mean error obtained with customized guides was 0.8 mm (range 0.1–1.9) in the anterior-posterior axis, 0.4 mm (range 0–1.4) in the vertical axis and 0.2 mm (range 0–1.1) in the horizontal axis. There were statistically significant differences in the anterior-posterior and vertical axes in favour of the customized implants, whereas there were no differences in the horizontal plane. Furthermore, there was a mean reduction of the operative time of 36.5 min in the experimental group.
Within the limitations of the study it seems that patient specific surgical guides should be preferred when accuracy of repositioning of the maxilla and saving operative time are the priority.
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.
On the use of intraoperative 3D-RX C-arm imaging in orthognathic surgery: a prospective non-consecutive case series study
2024, Oral and Maxillofacial Surgery

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Oral and maxillofacial radiologyComputer-assisted orthognathic surgery: feasibility study using multiple CAD/CAM surgical splints

Objective

Materials and Methods

Results

Conclusions

Section snippets

Computer-Assisted Orthognathic Surgery: Virtual Planning and CAD/CAM Surgical Splints

Sample

Results

Discussion

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Computer-assisted orthognathic surgery: feasibility study using multiple CAD/CAM surgical splints