Accuracy of virtual surgical planning in two-jaw orthognathic surgery: comparison of planned and actual results

In-house CAD/CAM fabricated repositioning guide in maxillary repositioning after Le Fort I osteotomy

OBJECTIVE

This study aimed to compare the accuracy of two transferring methods, which are the intermediate splint made by computer-aided design (CAD)/computer-aided manufacturing (CAM) and the customized maxillary repositioning guide for orthognathic surgery.

MATERIALS AND METHODS

Patient data regarding virtual surgical simulations were collected. For analyzing the accuracy, the postoperative cone-beam computed tomography and preoperative simulation data were superimposed. The x, y, and z coordinates were obtained at three landmarks in the maxillary dentition, and the linear and angular differences between the surgical simulation and the actual surgery were evaluated.

RESULTS

Thirty-three patients were included in this study, 16 in the splint group and 17 in the guide group. One coordinate in the guide group and nine in the splint group showed errors of >2 mm, with a statistically significant difference. There was no significant difference between the two groups in the three-dimensional error distance at each reference point. In most measurements, the interquartile range of the guide group showed a narrower distribution than that of the splint group.

CONCLUSION

It is more advantageous to use a customized maxillary repositioning guide than an intermediate splint made via CAD/CAM to obtain an accuracy within the 2 mm discrepancy range.

A prospective cohort study on effects of mandibular setback with or without maxillary advancement for skeletal class III malocclusion on sleep-related respiratory parameters

PURPOSE

This study aimed to investigate changes in sleep-related respiratory parameters before and after orthognathic surgery in patients with skeletal class III malocclusion.

METHODS

Adults with skeletal class III malocclusion and treated with isolated mandibular setback or bimaxillary surgery (maxillary advancement and mandibular setback) were recruited. Sleep-related respiratory parameters were obtained with type III sleep study. Epworth Sleepiness Scale (ESS) was also recorded. The pre- and post-operative (6 months) data were compared. Correlations between these changes and pre-operative characteristics were analyzed. Subjects were categorized into three groups based on changes in the respiratory event index (REI) and 3% oxygen desaturation index: Δ ≤ -2.5, -2.5 < Δ < 2.5, and Δ ≥ 2.5. Amounts of surgical movement and pre-surgical parameters were compared among the 3 groups.

RESULTS

Thirty patients with an average age of 25.4 ± 5.0 years were recruited. Eleven patients underwent isolated mandibular setbacks while nineteen received bimaxillary surgery. Pre- and post-operative sleep-related respiratory parameters were not significantly different in the total samples, and when analyzed separately according to surgical procedures. Pre-operative ESS were correlated with the changes in REI (p = 0.01), average blood oxygen levels (p = 0.01), and snoring percentage (p = 0.04). Additionally, this study found that patients with a significant decrease in REI (ΔREI ≤ -2.5) after surgery had significantly higher pre-operative REI (6.2 events/hour) compared to those with minor REI changes (2.6 events/hour).

CONCLUSION

There was no significant change in sleep-related respiratory parameters following mandibular setbacks with or without maxillary advancement in this study.

TRAIL REGISTERED

This study was retrospectively registered and approved on February 11, 2025, under registration number TCTR20250211002.

Accuracy of Two Different Patient-Specific Drill/Cutting Guides for Maxillary Repositioning When Used for Minimally Invasive Bimaxillary Orthognathic Surgery

BACKGROUND

Minimally invasive orthognathic surgery (MIOS) involves smaller incisions and minimal tissue dissection. Most MIOS is done using interim splints to position the first jaw. The application of patient-specific implants in MIOS is difficult due to the size of traditional cutting/drill guides, which require larger incisions. As a result, MIOS guides were redesigned for this study to fit into smaller incisions.

PURPOSE

The study purpose was to estimate and compare the accuracy of the smaller and redesigned bone-borne (BB) versus bone/tooth-borne (BTB) cutting/drilling guides used in minimally invasive bimaxillary orthognathic surgery.

STUDY DESIGN, SETTING, SAMPLE

This retrospective cohort study included consecutive MIOS patients treated by a single surgeon at the University of Texas Health San Antonio from June 2023 to September 2024. It included patients that underwent bimaxillary MIOS with complete preoperative and postoperative cone-beam computed tomographic records. Exclusion criteria included craniofacial syndromes, severe medical comorbidities, or single-jaw surgery.

PREDICTOR VARIABLE

The primary predictor variable was the type of cutting/drilling guide (BB vs BTB) used to perform maxillary osteotomy.

MAIN OUTCOME VARIABLE(S)

The primary outcome variable was accuracy, defined as mean linear discrepancy that is closest to 0 mm. Linear discrepancies between planned and actual maxillary movements were measured.

COVARIATES

Demographics and malocclusion type.

ANALYSES

χ2 tests compared categorical variables, and Student's t-tests assessed accuracy differences. A P value < .05 was considered significant, with a Bonferroni correction applied for multiple comparisons.

RESULTS

The sample consisted of 20 patients (15 females, 75%; 5 males, 25%; mean age 24 ± 11.3 years) evenly divided into BB (n = 10) and BTB (n = 10) guide groups. The BTB guide demonstrated superior vertical accuracy for the upper incisor (mean difference: 0.67 mm, standard deviation = 0.33, P = .02) and the upper left canine (mean difference: 0.11 mm, standard deviation = 0.04, P = .03) when comparing means. However, no significant differences were found in root mean square discrepancies (P > .2) or other measurements (P > .06).

CONCLUSIONS AND RELEVANCE

Both guides achieved acceptable accuracy overall, with the BTB guide showing superior precision for 2 of the 11 landmarks.

Role of artificial intelligence in treatment planning and outcome prediction of jaw corrective surgeries by using 3-D imaging: a systematic review

OBJECTIVE

Artificial intelligence (AI) has been increasingly utilized in diagnosis of skeletal deformities, while its role in treatment planning and outcome prediction of jaw corrective surgeries with 3-dimensional (3D) imaging remains underexplored.

METHODS

The comprehensive search was done in PubMed, Google scholar, Semantic scholar and Cochrane Library between January 2000 and May 2024. Inclusion criteria encompassed studies on AI applications in treatment planning and outcome prediction for jaw corrective surgeries using 3D imaging. Data extracted included study details, AI algorithms, and performance metrics. Modified PROBAST tool was used to assess the risk of bias (ROB).

RESULTS

Fourteen studies were included. 11 studies used deep learning algorithms, and 3 employed machine learning on CT data. In treatment planning the prediction error was 0.292 to 3.32 mm (N = 5), and Dice score was 92.24 to 96% (N = 2). Accuracy of outcome predictions varied from 85.7% to 99.98% (N = 2). ROB was low in most of the included studies. A meta-analysis was not conducted due to significant heterogeneity and insufficient data reporting in the included studies.

CONCLUSION

3D imaging-based AI models in treatment planning and outcome prediction for jaw corrective surgeries show promise but remain at proof-of-concept. Further, prospective multicentric studies are needed to validate these findings.

Does the Sequence of Bimaxillary Orthognathic Surgery Affect Accuracy in Skeletal Class III Patients?

BACKGROUND

It is necessary to determine whether the sequence of maxillary and mandibular surgeries in bimaxillary orthognathic surgery affects the accuracy of surgical outcomes.

PURPOSE

The study aimed to measure and compare the accuracy among patients who underwent maxilla-first versus mandible-first bimaxillary surgery to correct a class III skeletal pattern.

STUDY DESIGN, SETTING, SAMPLE

This retrospective cohort study included consecutive patients treated by a single surgeon at one center using Le Fort I and bilateral sagittal split osteotomy surgery. Exclusions included patients scheduled for one-jaw or maxilla-segmental surgery and those with craniofacial syndromes, such as clefts.

PREDICTOR VARIABLE

The predictor variable was operative sequence for bimaxillary operations, divided into maxilla- or mandible-first groups.

OUTCOME VARIABLE

The outcome variable was accuracy, measured using linear discrepancies between landmarks in the virtual plan and actual operative outcomes. The measurement of linear discrepancy that was closer to 0 was considered the more accurate result.

COVARIATES

Sex, age, maxilla sagittal rotation degree, amount of posterior maxilla impaction, mandibular autorotation (°), and intermediate splint thickness (mm) were the covariates.

ANALYSES

Statistical analysis was performed using Student's t-test and Pearson's correlation, with statistical significance set at P < .05.

RESULTS

The sample comprised 60 patients with a mean age of 22.8 ± 3.7 years, of whom 36 (60%) were male. In the maxilla-first group, there were 30 subjects (60% male; mean age: 23.1 ± 4.2 years), with a mean mandibular autorotation of 0.41° (range: 0°-2.5°). The mandible-first group comprised 30 patients (60% male; mean age: 22.6 ± 3.3 years), with a mean mandibular autorotation of 5.46° (range: 1.9°-9.2°). The linear discrepancies for all landmarks did not significantly differ between mandible- and maxilla-first groups (P > .18). The mean three-dimensional discrepancies for all landmarks in maxilla-first group was 1.23 ± 0.5 mm and 1.23 ± 0.33 mm in mandible-first group, with no significant difference observed between the groups (P > .98). The amount of mandibular autorotation for intermediate splint application showed no significant correlation with the linear discrepancies (P > .58).

CONCLUSION AND RELEVANCE

In patients with skeletal class III malocclusion, mandible-first surgery in bimaxillary orthognathic surgery demonstrates accurate outcomes comparable to maxilla-first surgery.

Accuracy of 3D Virtual Surgical Planning Compared to the Traditional Two-Dimensional Method in Orthognathic Surgery: A Literature Review

With the innovation of three-dimensional imaging and printing techniques, computer-aided surgical planning, also known as virtual surgical planning (VSP), has revolutionized orthognathic surgery. Designing and manufacturing patient-specific surgical guides using three-dimensional printing techniques to improve surgical outcomes is now possible. This article presents an overview of VSP in orthognathic surgery and discusses the advantages and accuracy of this technique compared to traditional surgical planning (TSP). A PubMed and Google Scholar search was conducted to find relevant articles published over the past 10 years. The search revealed 2,581 articles, of which 36 full-text articles specifically addressed the topic of this study. The review concludes that VSP in orthognathic surgery provides optimal functional and aesthetic results, enhances patient satisfaction, ensures precise translation of the treatment plan, and facilitates intraoperative manipulation.

Customized Genioplasty and Advantages of 3D Virtual Planning: An Updated Literature Review

Genioplasty is a surgical technique that modifies the projection of the chin in three dimensions to achieve symmetry and facial harmonization. Virtual 3D planning is increasingly used, supplanting the conventional surgical technique due to the precise and predictable results obtained.The definition of the objective of the study was first carried out using the PICO (Patient, Intervention, Comparison, Outcome) question method. Posteriorly, an updated literature review was carried out in the "PubMed" database using the keywords "Genioplasty and Virtual 3D Planning," obtaining 11 articles for the study with the objective of defining the advantages and disadvantages of performing a virtually planned genioplasty, comparing it with the conventional technique.In the results, it is observed that virtually planned genioplasty presents greater precision, a reduction in surgical time, and a lower rate of complications than the conventional technique. Virtual planning using computer-aided design/computer-aided manufacturing technology presents good reproducibility in the patient with <2 mm variations between what was planned and what was obtained postoperatively, with statistically significant results (p < 0.001).In conclusion, virtually planned genioplasty with customized cutting guides and osteosynthesis plates achieves very precise surgery results with good reproducibility, reducing surgical time, intraoperative complications, and the difficulty of the surgical technique.

Accuracy of maxillary repositioning surgery in teaching hospitals using conventional model surgery

PURPOSE

The aim of this study was to assess the accuracy of maxillary repositioning surgery in teaching hospitals using conventional model surgery.

MATERIALS AND METHODS

A total of 73 patients undergoing single-piece LeFort I osteotomies in the maxilla and bilateral sagittal split osteotomies in the mandible were included in the study. Preoperative and immediate postoperative cone-beam CT were compared in computer software (Dolphin3D©). Maxillary landmarks relative to the vertical and horizontal reference lines were evaluated. The difference between the planned and achieved maxillary positions was measured. Distance error in millimeters and achievement ratio (achieved displacement/planned displacement*100) were calculated for different maxillary movements.

RESULTS

Midline correction and advancement were the most accurate movements with an overall mean distance error of 0.53 mm and 0.63 mm respectively while posterior impaction and setback were the least accurate movements with 1.38 mm and 1.76 mm mean discrepancies, respectively. A significant difference was observed only in setback movement regarding the discrepancy value (P < .05). Although setback and down-graft movements tended to under-correction, all other movements were overcorrected. As the magnitude of maxillary movements increases, the accuracy decreases. In severe displacements (≥ 8 mm), the accuracy declines significantly (P < .05).

CONCLUSION

Classic cast surgery and manually fabricated intermediate splints in teaching hospitals yield accurate and acceptable results in the majority of cases (84.6%). The accuracy of maxillary repositioning decreases as the magnitude of displacement increases.

Evaluation of Soft Tissue Changes Following Orthognathic Surgery Using Virtual Surgical Planning Software

CONTEXT

Orthognathic surgery brings about a harmonious relationship between jaws, resulting in improved facial aesthetics. It is key to analyze if satisfactory results can be attained by using virtual surgical planning for orthognathic procedures so as to recommend it for routine clinical practice.

AIMS

The aims of this study were to evaluate the various soft tissue changes that take place following orthognathic surgery using three-dimensional (3D) imaging and virtual surgical planning software and quantify the accuracy of virtual surgical planning software on patients undergoing orthognathic surgery.

SETTINGS AND DESIGN

This is an observational prospective study with a sample size of 12.

METHODS AND MATERIALS

In this prospective study, 12 patients undergoing orthognathic surgery were included following the inclusion and exclusion criteria. A usual pre-surgical work-up was done and a 3D replica of the facial skeleton was formulated using the software with the DICOM data acquired from the patient i.e., CT and scans of patient's dentition. Virtual surgical planning was done and splints were manufactured according to the desired newly achieved position. Patients were operated following the virtual surgical plan guided by the computer-aided design and computer-aided manufacturing (CAD-CAM) splints. Post-operative evaluation was done. As the study is more of a descriptive study to obtain detailed knowledge of a new procedure, only one group is being studied and hence there is no statistical testing included in this study.

RESULTS

The mean discrepancy noticed after superimposition of soft tissue points was 0.92 with a standard deviation of 0.3.

CONCLUSIONS

3D CT virtual surgical planning is a reliable tool to achieve predictable and reliable post-operative results in orthognathic surgical cases.

Enhancing skeletal stability and Class III correction through active orthodontist engagement in virtual surgical planning: A voxel-based 3-dimensional analysis

INTRODUCTION

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

Three-dimensional positioning of the maxilla using novel intermediate splints in maxilla-first orthognathic surgery for correction of skeletal class III deformity

OBJECTIVES

Successful orthognathic surgery requires accurate transfer of the intraoperative surgical plan. This study aimed to (1) evaluate the surgical error of a novel intermediate splint in positioning the maxilla during maxilla-first orthognathic surgery and (2) determine factors influencing surgical error.

MATERIALS AND METHODS

This prospective study examined 83 patients who consecutively underwent Le Fort I osteotomy for correction of skeletal class III deformity using a novel intermediate splint and a bilateral sagittal split osteotomy. Surgical error was the outcome variable, measured as the difference in postoperative translational and rotational maxillary position from the virtual plan. Measures included asymmetry, need and amount for mandibular opening during fabrication of intermediate splints, and planned and achieved skeletal movement.

RESULTS

Mean errors in translation for vertical, sagittal, and transversal dimensions were 1.0 ± 0.7 mm, 1.0 ± 0.6 mm, and 0.7 ± 0.6 mm, respectively; degrees in rotation for yaw, roll, and pitch were 0.8 ± 0.6, 0.6 ± 0.4, and 1.6 ± 1.1, respectively. The transverse error was smaller than sagittal and vertical errors; error for pitch was larger than roll and yaw (both p < 0.001). Error for sagittal, transverse, and roll positioning was affected by the achieved skeletal movement (roll, p < 0.05; pitch and yaw, p < 0.001). Surgical error of pitch positioning was affected by planned and achieved skeletal movement (both p < 0.001).

CONCLUSIONS

Using the novel intermediate splint when performing Le Fort I osteotomy allowed for accurate positioning of the maxilla.

CLINICAL RELEVANCE

The novel intermediate splint for maxillary positioning can be reliably used in clinical routines.

Applications of Cone Beam Computed Tomography Scans in Dental Medicine and Potential Medicolegal Issues

A cone beam central tomography (CBCT) scan produces images in orthogonal and non-orthogonal with great spatial resolution. When a dental health care practitioner (DHP) orders a CBCT scan, they should consider if it is truly indicated, as CBCT scans carry up to four times the dosage of radiation compared to panoramic radiographs. Any diagnostic imaging obtained of a patient should include a formal interpretive report commenting on the findings within the imaging. Ordering of limited field of view (FOV) CBCT scans and failing to report on abnormal findings present outside of the region of interest (ROI) is a potential medicolegal issue.

Are Virtually Designed 3D Printed Surgical Splints Accurate Enough for Maxillary Reposition as an Intermediate Orthognathic Surgical Guide

Background and Aim

The accuracy of the virtually-designed 3D-printed surgical splints requires investigation for the practical use of surgical plan in the operating room. This study aimed to compare the validity of the 3D-printed and the conventional intermediate splints and evaluate the outcomes after the surgical application of the 3D-printed splint compared with the predicted values.

Methods

In this study, ten patients with dentofacial deformity were recruited. Participants were analyzed by the conventional surgical planning and virtual surgical planning. The intermediate surgical splints were created by the conventional and 3D-printing methods. Maxillary movements in 3 spatial directions were measured in an articulator after the application of both splints. Correlation and agreement between the two methods were tested by intraclass correlation coefficient (ICC). After the confirmation of 3D printed splint validity for each patient, the surgery was performed using 3D printed splints. It is assumed that ideally cephalometric prediction values are going to be obtained using conventional acrylic splints (gold standard). So, as a second objective, the outcome of the surgically-applied 3D-printed splint was evaluated and compared with the predicted values and finally analyzed by the paired t-test.

Results

Based on the observations, there was an excellent agreement between the virtually-designed 3D-printed and conventional intermediate surgical splints (ICC ranged between 0.83 and 0.99 for linear values). There was a good cumulative agreement of ICC greater than 0.80. Overall, the mean linear measurements were not different between conventional and 3D-printed splint on the articulator. Also, there were no significant differences between the linear and angular measurements of 2D-cephalometric prediction and postoperation values.

Conclusion

The results showed cautiously the acceptable accuracy of the 3D-printed splints for several parameters in three spatial dimensions within the laboratory and clinical settings.

Accuracy of hard and soft tissue prediction using three-dimensional simulation software in bimaxillary osteotomies: A systematic review

INTRODUCTION

Orthognathic surgery is considered nowadays as a revolutionary treatment option for treating skeletal discrepancies and severe malocclusions in the sagittal, vertical and transverse dimensions. This surgery allows both the restoration of facial harmony and the achievement of satisfactory dental occlusion. The technology of computer-assisted surgeries including virtual surgical simulation programs and planning software greatly contributes to providing a three-dimensional simulation and precise mobilization of the maxilla and/or mandible, thus allowing the prediction of the final outcome in soft tissues. This study aims to systematically review the available scientific literature about the accuracy of the hard and soft tissue predictions delivered by the many promoted three-dimensional simulation software.

MATERIAL AND METHODS

An electronic search was conducted on various databases: Medline via PubMed, The Cochrane Library, EBSCO-host, and Web of Science. The search was established on a well-defined research question following PICO principle: population, intervention, comparator and outcome. Search evaluation and the assessment of risk of bias were undertaken in each study following its type and design.

RESULTS

Fifteen studies were included for qualitative analysis. Seven studies evaluated the accuracy of soft tissue prediction, seven focused more on the accuracy of hard tissue and one study assessed both hard and soft tissue prediction accuracy delivered by the simulation software. Moreover, three studies were judged to be low risk and four were classified as high risk. Included studies revealed that hard tissue prediction is highly accurate and reliable, leading to clinically acceptable results. Yet, soft tissue prediction is unclear due to various factors that bias its results. Caution should therefore be taken when providing information about the soft tissue planning to patients.

CONCLUSIONS

Computer assisted 3D simulation protocols allow for more precise repositioning of the maxilla and/or mandible compared to conventional 2D methods. However, 3D soft tissue prediction using simulation software remains less accurate, especially in the labial region.

Reproducibility and reliability of digital occlusal planning for orthognathic surgery

The digital articulation of dental models is gradually replacing the conventional physical approach for occlusal prediction planning. This study was performed to compare the accuracy and reproducibility of free-hand articulation of two groups of digital and physical dental models, 12 Class I (group 1) and 12 Class III (group 2). The models were scanned using an intraoral scanner. The physical and digital models were independently articulated 2 weeks apart by three orthodontists to achieve the maximum inter-digitation, with coincident midlines and a positive overjet and overbite. The occlusal contacts provided by the software color-coded maps were assessed and the differences in the pitch, roll, and yaw were measured. The reproducibility of the achieved occlusion of both the physical and digital articulation was excellent. The z-axis displayed the smallest absolute mean differences of 0.10 ± 0.08 mm and 0.27 ± 0.24 mm in the repeated physical and repeated digital articulations, respectively, both in group 2. The largest discrepancies between the two methods of articulation were in the y-axis (0.76 ± 0.60 mm, P = 0.010) and in roll (1.83° ± 1.72°, P = 0.005). The overall measured differences were< 0.8 mm and< 2°. Despite the steep learning curve, digital occlusal planning is accurate enough for clinical applications.

Maximizing the Virtual Surgical Planning Session for Orthognathic Surgery

Virtual surgical planning (VSP) and computer-aided design/computer-aided manufacturing have become essential tools for planning orthognathic surgery. Despite widespread use, empirical gaps still exist in the literature regarding the logistics of the orthognathic planning session itself. More precisely, there is a need to explicate the VSP workflow on which specific parameters are needed for a translation into 3D software. Although each surgeon has his/her theoretical framework, none have been elucidated to properly communicate the necessary pieces of information needed to plan the correction of a variety of dentofacial deformities. The authors provide an outline for conducting a successful VSP planning session for orthognathic surgery.

Accuracy of virtual surgical planning in bimaxillary orthognathic surgery with mandible first sequence: A retrospective study

The aim of this study was to verify treatment accuracy using virtual surgical planning (VSP) with a mandible-first sequence and strict surgical protocol to determine what surgical and methodological factors might influence outcomes. VSP transfer accuracy was evaluated retrospectively through a modified method involving voxel-based superimposition in patients who had undergone bimaxillary surgery with a mandible-first sequence to correct dentoskeletal deformities. Data analysis showed that the movements planned and those executed were substantially equivalent (p < 0.01), with the exception of mandibular and maxillary sagittal movements that were 0.72 ± 0.90 mm and 1.41 ± 1.04 mm smaller, respectively, than planned. This study showed that a mandible-first sequence is accurate for transferring virtual surgical planning intraoperatively. There are several factors involved in the proper transfer of virtual planning beyond the software, such as surgical technique and sequencing. Inaccurate sagittal movements and maxillary repositioning seem to depend mainly on surgical factors.

The Last 40 Years of Orthognathic Surgery: A Bibliometric Analysis

PURPOSE

Bibliometric analyses provide information on the effectiveness, performance, trends, and various other characteristics of research by using mathematical and statistical analysis methods for data related to scientific publications. This study aims to determine the focus of studies in the field of orthognathic surgery, map it, and present the results in a simplified manner through a comprehensive bibliometric analysis of the relevant literature.

METHODS

In this bibliometric analysis study, orthognathic surgery publications from 1980 to 2022 were retrieved from the Web of Science Core Collection database. The independent variables were co-citations, while the outcome variables included cross-country collaboration analysis, keyword analysis, co-citation analysis, and cluster analysis of the co-citation network. Covariates were the number of publications, number of citations, year range, centrality value, and silhouette value. The bibliometric analysis was conducted using CiteSpace, VOSviewer, and R-Studio software.

RESULTS

A total of 7,135 publications and 75,822 references were included in the analysis, and the annual growth rate of publications was 9.52%. The co-citation clustering analysis revealed that the orthognathic surgery literature was organized into 16 subject headings. Patient satisfaction was found to be the most widely published topic. The youngest clusters, representing new topics in the field, were virtual planning and examination of condylar changes after orthognathic surgery.

CONCLUSION

Bibliometric analysis methods were used to evaluate the 40-year history of the orthognathic surgery literature. The analysis identified the most influential publications, the topics in which the literature is divided, and hot spots in the field. By conducting similar bibliometric research studies in the future, the progress and future direction of the literature can be monitored based on evidence.

Early experience of wafer-free Le Fort I osteotomy with patient-specific implants in cleft lip and palate patients

PURPOSE

The use of virtual surgical planning and patient-specific saw and drill guides combined with customized osteosynthesis is becoming a gold standard in orthognathic surgery. The aim of this study is to report preliminary results of the use of virtual surgical planning and the wafer-free PSI technique in cleft patients.

MATERIALS AND METHODS

Patient-specific saw and drill guides combined with milled patient-specific 3D titanium alloy implants were used in reposition and fixation in Le Fort I osteotomy of 12 cleft patients. Surgical information was retrieved from hospital records. Pre- and post-operative lateral cephalograms were analyzed.

RESULTS

In 10 of 12 cases, the implants fitted as planned to predesigned drill holes and bone contours with high precision. In one patient, the mobilization of the maxilla was too demanding for virtually planned advancement, and the implants could not be used. In another patient, PSI fitting was impaired due to an insufficient mobilization of maxilla and tension on PSI fixation with screws. After the surgery, the mean advancement of the anterior maxilla (point A) of all patients was 5.8 mm horizontally (range 2.7-10.1) and -3.1 mm vertically (range -9.2 to 3.4). Skeletal relationships of the maxilla and mandible could be corrected successfully in all patients except for the one whose PSI could not be used.

CONCLUSIONS

Virtual surgical planning combined with PSI is a possible useful clinical adjunct for the correction of maxillary hypoplasia in cleft patients. Large maxillary advancements and scarring may be cause problems for desired advancement and for the use of implants.

Three-Dimensional Accuracy and Stability of Personalized Implants in Orthognathic Surgery: A Systematic Review and a Meta-Analysis

This systematic review aimed to determine the accuracy/stability of patient-specific osteosynthesis (PSI) in orthognathic surgery according to three-dimensional (3D) outcome analysis and in comparison to conventional osteosynthesis and computer-aided designed and manufactured (CAD/CAM) splints or wafers. The PRISMA guidelines were followed and six academic databases and Google Scholar were searched. Records reporting 3D accuracy/stability measurements of bony segments fixated with PSI were included. Of 485 initial records, 21 met the eligibility (566 subjects), nine of which also qualified for a meta-analysis (164 subjects). Six studies had a high risk of bias (29%), and the rest were of low or moderate risk. Procedures comprised either single-piece or segmental Le Fort I and/or mandibular osteotomy and/or genioplasty. A stratified meta-analysis including 115 subjects with single-piece Le Fort I PSI showed that the largest absolute mean deviations were 0.5 mm antero-posteriorly and 0.65° in pitch. PSIs were up to 0.85 mm and 2.35° more accurate than conventional osteosynthesis with CAD/CAM splint or wafer (p < 0.0001). However, the clinical relevance of the improved accuracy has not been shown. The literature on PSI for multi-piece Le Fort I, mandibular osteotomies and genioplasty procedure is characterized by high methodological heterogeneity and a lack of randomized controlled trials. The literature is lacking on the 3D stability of bony segments fixated with PSI.

Trends in Craniofacial Fellowship Career Outcomes: A Call for Expanding Professional Opportunities in Craniofacial Surgery

PURPOSE

Limited available pediatric plastic surgery positions fail to accommodate the increasing number of craniofacial fellows trained annually. However, many adult indications have increased the demand for craniofacial expertise. Given new opportunities available to craniofacial surgeons, the authors aim to evaluate career prospects for recent craniofacial graduates and explore additional career opportunities.

METHODS

Upon approval from the American Society of Craniofacial Surgeons (ASCFS), an anonymous online survey invitation was sent to craniofacial fellows who graduated from 2016 to 2021. Respondents were queried regarding their craniofacial fellowship and subsequent career prospects.

RESULTS

A total of 124 eligible participants were identified, of which 30 (24.2%) responded. Craniomaxillofacial case distribution at respondents' current practices varied, with 42.3% reporting a 50% to 75% craniofacial caseload and 38.5% reporting less than 25%. Craniofacial trauma reconstruction was performed most at current positions (92.3%), followed by general reconstruction (92.3%) and breast surgery (69.2%); the least commonly performed was facial feminization (23.1%). Most respondents desired an increased craniomaxillofacial caseload (65.4%). However, 26.9% were unable to secure their current position before fellowship completion, and 80.0% cited limited craniofacial job availability. Recommendations to improve fellowship comprehensiveness and increase candidate competitiveness included increased facial feminization, facial esthetic, and microsurgical experience.

CONCLUSION

To adapt to trends in craniomaxillofacial surgery, ASCFS should encourage developing fellowships that increase exposure to gender-affirming, adult craniofacial reconstruction, orthognathic, and skeletal facial esthetic surgery. Expanding training beyond congenital deformities can provide additional employment opportunities while maintaining excellence and innovation in facial plastic surgery.

Accuracy of Maxillary Positioning During Orthognathic Surgery: A Comparison of Web-based 3-Dimensional Virtual Surgical Planning and Actual Outcomes

PURPOSE

To determine the accuracy of planned maxillary positioning by virtual surgery by comparing planned and actual postoperative outcomes.

MATERIALS AND METHODS

Twenty patients who underwent 2-jaw orthognathic surgery performed by a single surgeon from May 2017 to December 2020 were the subjects of this retrospective study. The coordinates of reference points in horizontal, sagittal, and coronal planes as determined by virtual surgery were compared with those of actual surgical outcomes. The reference points used were as follows: #16 mesiobuccal cusp tip (#16), #26 mesiobuccal cusp tip (#26), and #11 mesial tip (U1); anterior nasal spine; and posterior nasal spine. Three-dimensional linear distances between the reference point on which virtual surgery was performed and the reference point after the actual operation was calculated.

RESULTS

Of the 20 patients, there were 11 males and 9 females of average age 20.65±2.41 years. Three-dimensional printed wafers had high accuracy with a maximum difference of 0.3 mm. No significant difference was observed in horizontal or coronal planes for any reference point, but a significant difference was observed in the sagittal plane. However, positional differences between planned and actual reference points were all <1 mm.

CONCLUSIONS

Virtual surgical planning and 3-dimensional printed wafer achieved excellent maxillary positioning accuracies after orthognathic surgery.

The Accuracy of 3D Surgical Design and Simulation in Prefabricated Fibula Free Flaps for Jaw Reconstruction

The ideal jaw reconstruction involves the restoration and maintenance of jaw continuity, jaw relations, joint alignment, and facial contour, and, most importantly, dental occlusal reconstruction. One of the essential requirements of achieving a consistent functional outcome is to place the bony reconstruction in the correct three-dimensional position as it relates to the other jaw segments and dentition. A protocol of occlusion-driven reconstruction of prefabricated fibular free flaps that are customized to the patient with surgical design and simulation (SDS)-planned osseointegrated implant installation was developed by our institution. This innovation introduced significant flexibility and efficiency to jaw reconstructions, but functional and cosmetic outcomes were dependent on the accuracy of the final reconstructions when compared to the SDS plan. The purpose of this study was to examine the accuracy of the SDS-planned fibular flap prefabrication in a cohort of patients undergoing jaw reconstruction. All patients that had undergone primary jaw reconstruction with prefabricated fibular free flaps were reviewed. The primary outcome of this study was the accuracy of the postoperative implant positions as compared to the SDS plan. A total of 23 implants were included in the analysis. All flaps survived, there was no implant loss postoperatively, and all the patients underwent all stages of the reconstruction. SDS planning of fibular flap prefabrication resulted in better than 2 mm accuracy of osteointegrated implant placement in a cohort of patients undergoing jaw reconstruction. This accuracy could potentially result in improved functional and cosmetic outcomes.

Three-Dimensional Comparison of the Maxillary Surfaces through ICP-Type Algorithm: Accuracy Evaluation of CAD/CAM Technologies in Orthognathic Surgery

PURPOSE

This retrospective study aims to compare the accuracy of two different CAD/CAM systems in orthognathic surgery. The novelty of this work lies in the method of evaluating the accuracy, i.e., using an Iterative Closest Point (ICP) algorithm, which matches a pair of 2D or 3D point clouds with unknown dependencies of the transition from scan s_(k) to scan s_(k+1).

METHODS

The study population was composed of ten patients who presented to the Maxillofacial Surgery Department of the University "Sapienza" of Rome for the evaluation and management of skeletal malocclusions. The patients were divided into two groups, depending on the technique used: group 1: splintless group (custom-made cutting guide and plates); group 2: splint group (using a 3D-printed splint). STL files were imported into Geomagic^® Control X™ software, which allows for comparison and analysis using an ICP algorithm. The RMSE parameter (3D error) was used to calculate the accuracy. In addition, data were compared in two different patient subgroups. The first subgroup only underwent a monobloc Le Fort I osteotomy (p-value = 0.02), and the second subgroup underwent a Le Fort I osteotomy associated with a segmental osteotomy of the maxilla (p-value = 0.23).

RESULTS

Group 1 showed a 3D error of 1.22 mm ± SD 0.456, while group 2 showed a 3D error of 1.63 mm ± SD 0.303. These results have allowed us to compare the accuracy of the two CAD/CAM systems (p-value = 0.09).

CONCLUSIONS

The ICP algorithm provided a reproducible method of comparison. The splintless method would seem more accurate (p-value = 0.02) in transferring the surgical programming into the operating room when only a Le Fort I osteotomy is to be performed.

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.

3D Printing and Virtual Surgical Planning in Oral and Maxillofacial Surgery

Compared to traditional manufacturing methods, additive manufacturing and 3D printing stand out in their ability to rapidly fabricate complex structures and precise geometries. The growing need for products with different designs, purposes and materials led to the development of 3D printing, serving as a driving force for the 4th industrial revolution and digitization of manufacturing. 3D printing has had a global impact on healthcare, with patient-customized implants now replacing generic implantable medical devices. This revolution has had a particularly significant impact on oral and maxillofacial surgery, where surgeons rely on precision medicine in everyday practice. Trauma, orthognathic surgery and total joint replacement therapy represent several examples of treatments improved by 3D technologies. The widespread and rapid implementation of 3D technologies in clinical settings has led to the development of point-of-care treatment facilities with in-house infrastructure, enabling surgical teams to participate in the 3D design and manufacturing of devices. 3D technologies have had a tremendous impact on clinical outcomes and on the way clinicians approach treatment planning. The current review offers our perspective on the implementation of 3D-based technologies in the field of oral and maxillofacial surgery, while indicating major clinical applications. Moreover, the current report outlines the 3D printing point-of-care concept in the field of oral and maxillofacial surgery.

Evaluation of postoperative changes in condylar positions after orthognathic surgery using balanced orthognathic surgery system

Background

Many studies on maintaining the condyle in a normal or anatomical position during orthognathic surgery have been conducted to stabilize surgical outcomes and prevent iatrogenic temporomandibular joint complications. The aim of this study is to evaluate the changes in condylar positions after orthognathic surgery using virtual surgical planning via the balanced orthognathic surgery (BOS) system.

Methods

Postoperative changes in condylar position were retrospectively evaluated in 22 condyles of 11 patients with skeletal class III malocclusion who underwent orthognathic surgery using virtual surgical planning via the BOS system. The center point coordinates of the condylar head before and after orthognathic surgery were analyzed using voxel-based registration.

Results

Changes in the condylar position mainly occurred downward in the y-axis (−1.09 ± 0.62 mm) (P < 0.05). The change in the x-axis (0.02 ± 0.68 mm) and z-axis (0.01 ± 0.48 mm) showed no significant difference between before and after orthognathic surgery.

Conclusion

These results indicate that the changes in the condylar positions after orthognathic surgery using virtual surgical planning via the BOS system mainly occurred downward in the y-axis, with slight changes in the x- and z-axes. The change in the condylar position after orthognathic surgery using the BOS system is clinically acceptable.

Accuracy of virtual surgical planning in segmental osteotomy in combination with bimaxillary orthognathic surgery with surgery first approach

Background

This study aimed to assess the accuracy of virtual surgical planning (VSP) in segmental osteotomy in combination with bimaxillary orthognathic surgery with surgery first approach (SFA) by means of three-dimensional (3D) measuring and superimposition, so as to promote the application of digital technology in combined orthodontic-orthognathic treatment.

Methods

20 patients treated with segmental osteotomy in combination with bimaxillary orthognathic surgery with SFA from 2018 to 2020 were included. All of them acquired VSP performed by ProPlan CMF 3.0 software (Materialise Corporation, Belgium). The preoperative (T0) 3D model of VSP and the postoperative (T1) 3D model, reconstructed by the cone-beam computed tomography (CBCT) data acquired one week after surgery, were compared by measuring the 3D coordinates of the landmarks as well as 3D model superimposition for deviation analysis. The deviation analysis was achieved by Geomagic Studio 2013 (3D Systems Corporation, USA). The differences which represented the accuracy of VSP were evaluated by the root mean square deviation (RMSD) and the Bland–Altman method.

Results

There was no statistically significant difference between the 3D coordinates of T1 and T0 (P > 0.05), and the mean overall RMSD was 1.37 mm, within the clinical relevance of 2 mm. The RMSD of sagittal direction (1.76 mm) was greater than that of coronal and vertical directions (1.09 mm and 1.24 mm), and the RMSD of maxillary and mandibular aspects were basically equal (1.30 mm and 1.45 mm). The Bland–Altman method showed the T0 and T1 measurements were in good agreement. The mean RMSD obtained from the deviation analysis was 1.85 mm, within the clinical relevance.

Conclusions

VSP in segmental osteotomy in combination with bimaxillary orthognathic surgery with SFA proved to acquire accurate outcome in this study.

Accurate transfer of bimaxillary orthognathic surgical plans using computer-aided intraoperative navigation

Objective

To examine the accuracy of computer-aided intraoperative navigation (Ci-Navi) in bimaxillary orthognathic surgery by comparing preoperative planning and postoperative outcome.

Methods

The study comprised 45 patients with congenital dentomaxillofacial deformities who were scheduled to undergo bimaxillary orthognathic surgery. Virtual bimaxillary orthognathic surgery was simulated using Mimics software. Intraoperatively, a Le Fort I osteotomy of the maxilla was performed using osteotomy guide plates. After the Le Fort I osteotomy and bilateral sagittal split ramus osteotomy of the mandible, the mobilized maxilla and the distal mandibular segment were fixed using an occlusal splint, forming the maxillomandibular complex (MMC). Realtime Ci-Navi was used to lead the MMC in the designated direction. Osteoplasty of the inferior border of the mandible was performed using Ci-Navi when facial symmetry and skeletal harmony were of concern. Linear and angular distinctions between preoperative planning and postoperative outcomes were calculated.

Results

The mean linear difference was 0.79 mm (maxilla: 0.62 mm, mandible: 0.88 mm) and the overall mean angular difference was 1.20°. The observed difference in the upper incisor point to the Frankfort horizontal plane, midfacial sagittal plane, and coronal plane was < 1 mm in 40 cases.

Conclusions

This study demonstrates the role of Ci-Navi in the accurate positioning of bone segments during bimaxillary orthognathic surgery. Ci-Navi was found to be a reliable method for the accurate transfer of the surgical plan during an operation.

Evaluation of the accuracy of virtual planning in bimaxillary orthognathic surgery: Systematic review

The purpose of this research was to evaluate the accuracy of virtual planning in bimaxillary orthognathic surgery in bone by comparing the mean linear and angular measurements of the surgical plan with the actual surgical result. Electronic databases, MEDLINE via PubMed, Web of Science, SCOPUS, the Cochrane Library, grey literature, and the American clinical trials registry (www.ClinicalTrials.gov), were accessed as search engines. The studies consisted of publications on the assessment of accuracy in virtual planning in bimaxillary orthognathic surgery between 2010 and 2020. After application of the eligibility criteria, 26 articles were included, and their quality was evaluated using the methodological index for non-randomised studies (MINORS) tool and Cohen's kappa statistic in the MedCalc program (MedCalc Software Ltd). Evidence obtained by comparing the planning and surgical results, both in the maxilla and mandible, showed that there is great accuracy in virtual planning in bimaxillary orthognathic surgery.

Conformity of the Virtual Surgical Plan to the Actual Result Comparing Five Craniofacial Procedure Types

BACKGROUND

The "accuracy" of virtual surgical planning across multiple procedure types is not known. The authors aimed to compare the planned outcome from virtual surgical planning to the actual postoperative outcome for five craniofacial procedure types performed by a single surgeon: implant cranioplasty, cranial vault remodeling, orthognathic surgery, mandible reconstruction, and mandibular distraction.

METHODS

Stereolithography formats were obtained from virtual surgical planning and compared to postoperative computed tomographic scans for consecutive patients who underwent one of the five procedure types. Volumetric renderings of the operated bony region of interest were overlaid and compared using a Boolean operation to compute conformity (as a percentage of the region of interest). Conformity across procedure type was analyzed using analysis of variance and post hoc Bonferroni analysis, where appropriate.

RESULTS

One hundred thirty patients were included (51.5 percent male and 49.5 percent female; mean age, 27 years; 59 orthognathic surgery, 32 cranial vault remodeling, 16 mandible reconstruction, 12 mandibular distraction, and 11 implant cranioplasty patients). The highest tier of conformity was obtained for implant cranioplasty (median, 76.8 ± 10.3 percent) and mandible reconstruction (mean, 69.4 ± 11.2 percent), followed by orthognathic surgery (mean, 55.0 ± 7.3 percent) and mandibular distraction (median, 41.9 ± 20.3 percent), followed by cranial vault remodeling (mean, 22.2 ± 12.1 percent) (p < 0.001 between tiers and p > 0.05 among tiers).

CONCLUSIONS

Virtual surgical planning resulting in custom permanent implants and intraoperative guides provides more predictable results compared to virtual surgical planning used for procedures involving higher degrees of skeletal repositioning and postoperative movement (i.e., mandibular distraction and nonrigid cranial vault remodeling). In cases with expectedly lower conformity, excellent outcomes can be achieved with sound intraoperative judgment.

Randomized Controlled Clinical Trial to Assess the Utility of Computer-Aided Intraoperative Navigation in Bimaxillary Orthognathic Surgery

ABSTRACT

Accurate application of the preoperative surgical plan in actual surgical settings is of paramount importance in orthognathic surgery. This randomized controlled clinical trial aimed to evaluate the accuracy of computer-aided intraoperative navigation (Ci-Navi) compared with that of conventional navigation methods in bimaxillary orthognathic surgery. Fifty-two patients were randomly divided into 2 groups. Group A (n = 26) patients underwent surgery assisted with Ci-Navi and group B (n = 26) patients underwent surgery assisted with conventional intraoperative navigation methods. During the operation, after LeFort I osteotomy, the mobile maxilla was repositioned to the designated position either using assistance from real-time Ci-Navi (group A) or using an intermediate splint (group B). Intra- and intergroup linear and angular differences between preoperative planning and postoperative outcomes were calculated. In group A, the overall mean linear difference was 0.79 mm (0.62 mm for the maxilla and 0.88 mm for the mandible) and the overall mean angular difference was 1.20°. In 23 cases, the difference from the upper incisor point to the Frankfort horizontal plane, midfacial sagittal plane, and coronal plane was less than 1 mm. In group B, the overall mean linear difference was 1.98 mm (1.76 mm for the maxilla and 2.02 mm for the mandible) and the overall mean angular difference was 2.08°. The difference from the upper incisor point to the Frankfort horizontal plane, midfacial sagittal plane, and coronal plane was less than 1 mm in 15 cases. This study demonstrates the utility of Ci-Navi is superior to the conventional methods in aiding the accurate repositioning of bony segments in bimaxillary orthognathic surgery.

Reliability of cephalometric landmark identification on three-dimensional computed tomographic images

Our aims were to evaluate the reliability of three-dimensional (3D) cephalometric landmark identification in 3D images, and to propose an improved protocol for determining these landmarks. Computed tomographic (CT) images of 13 landmarks were obtained. One that did not show any artifacts, asymmetry in maxillofacial structures, or bony defects, was selected. Two orthodontic practitioners identified 3D cephalometric landmarks 10 times at one-week intervals. The distances of 26 landmarks were measured on the basis of three reference planes (coronal, horizontal, and sagittal). Ten mean (SD) measurements from each examiner were calculated, and the maximum and minimum values and the difference from the 10 measurements of each one were measured at a 95% confidence interval. Interexaminer differences for the three planes were found in the upper right first molar, point A, both gonions, left orbitale, and both porions. The lower right first molar, foramen magnum, gnathion, nasion, and pogonion showed interexaminer differences in two planes. Menton, basion, posterior nasal spine, upper and lower left first molar, and right mental foramen showed interexaminer differences in only one plane. With reference to intraexaminer differences, poor repeatability was observed for gonion, orbitale, condylion, and porion. Reliable 3D landmarks are the meeting point of sutures, distinct structures at converging planes, landmarks positioned in the midline, distinct anatomical structures such as the mental foramen, and teeth using multiplanar views.

Pediatric Orthognathic Surgery: National Analysis of Perioperative Complications

BACKGROUND

Orthognathic surgery has traditionally been performed after skeletal maturity. Although these procedures are also being performed in children, the implications of earlier intervention and specific risk factors in this younger population remain unknown.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program Pediatric dataset was queried for orthognathic procedures performed in 2018. Complications, readmissions, and reoperations were analyzed with appropriate statistics.

RESULTS

Overall adverse event rate after orthognathic surgery in pediatric patients was 7.8% (n = 22 of 281), which were associated with having any comorbidity (P < 0.001), overall respiratory comorbidities (P = 0.004), structural pulmonary abnormality (P < 0.001), developmental delay (P = 0.035), structural central nervous system abnormality (P < 0.001), and neuromuscular disorder (P = 0.035). Most common complications were excessive bleeding (2.5%), surgical site infection (1.1%), and pneumonia (0.7%). Orthognathic surgery in children below 6 years of age is associated with significantly increased adverse events (P < 0.001), including surgical site infection (P < 0.001), pneumonia (P = 0.022), readmission (P < 0.001), and reoperation (P < 0.001). Le Fort I osteotomies (P < 0.001) and bilateral sagittal split osteotomies (P = 0.009) took significantly longer for older patients in the years of permanent dentition than younger patients in the years of deciduous dentition. Single- and double-jaw procedures in pediatric patients have similarly low adverse events (P all ≥0.130). Interestingly, bilateral sagittal split osteotomies performed before 13.5 years of age were associated with a higher risk of adverse events (P = 0.012), such that these younger patients were 7.1 times more likely to experience adverse events if their procedure was performed earlier.

CONCLUSIONS

Orthognathic surgery is relatively safe, but children in the years of deciduous dentition under 6 years of age have significantly increased risk of adverse events.

Comparison of time and cost between conventional surgical planning and virtual surgical planning in orthognathic surgery in Korea

BACKGROUND

The purpose of this study was to measure the time of the conventional surgical planning (CSP) and virtual surgical planning (VSP) in orthognathic surgery and to compare them in terms of cost.

MATERIAL AND METHOD

This is a retrospective study of the patients who underwent orthognathic surgery at the OOOOO University Dental Hospital from December 2017 to August 2018. All the patients were analyzed through both CSP and VSP, and all the surgical stents were fabricated through manual and 3-dimensional (3D) printing. The predictor variables were the planning method (CSP vs. VSP) and the surgery type (group I: Le Fort I osteotomy+bilateral sagittal split osteotomy [LFI+BSSO] or group II: only bilateral sagittal split osteotomy [BSSO]), and the outcomes were the time and cost. The results were analyzed using paired t test.

RESULTS

Thirty patients (12 females, 18 males) met the inclusion criteria, and 17 patients were excluded from the study due to missing or incomplete data. There were 20 group I patients (LFI+BSSO regardless of genioplasty) and 10 group II patients (BSSO regardless of genioplasty). The average time of CSP for group I was 385±7.8 min, and that for group II was 195±8.33 min. The time reduction rate of VSP compared with CSP was 62.8% in group I and 41.5% in group II. On the other hand, there was no statistically significant cost reduction.

CONCLUSIONS

The time investment in VSP in this study was significantly smaller than that in CSP, and the difference was greater in group I than in group II.

Efficient in-house 3D printing of an orthognathic splint for single-jaw cases

The purpose of this paper is to outline a simple and effective digital protocol for in-house 3D-printing of orthognathic splints for use during single-jaw orthognathic surgery. Using this protocol, an intraoral scanner, and virtual planning software, computer-designed splints were fabricated by a rapid prototyping machine in-house. The protocol was utilized for 35 consecutive patients requiring single-jaw orthognathic surgery between January 2019 and March 2020. The total time from initial scan to splint fabrication for each case was between 5 and 9hours, including 3minutes for scanning of models, 4.5minutes for development of the splint, and 4-8hours for rapid prototyping and post-processing. This time varied based on the complexity of the design and the number of splints printed simultaneously. The average cost of raw materials for each splint was $0.73 Canadian dollars.

Virtually-Planned Orthognathic Surgery Achieves an Accurate Condylar Position

PURPOSE

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.

PATIENTS AND METHODS

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.

RESULTS

This study included 52 patients, 26 men and 26 women, with a mean age of 21 years and 3 months. 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 2.24 mm, respectively. Condylar landmarks, maxillary landmarks, and the landmarks on the distal segment of the mandible were positioned at 0.49 mm inferior, 0.28 mm anterior, and 1.25 mm inferior, respectively. The landmark errors for the distal segment of the mandible exhibited a wider distribution than those for condylar and maxillary landmarks.

CONCLUSIONS

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.

A comparative study of the accuracy between two computer-aided surgical simulation methods in virtual surgical planning

OBJECTIVE

The aim of this retrospective and observational study was to compare the accuracy of two different virtual surgical planning (VSP) protocols, namely, the CASS method and the modified CASS method.

MATERIALS AND METHODS

The patients underwent bimaxillary orthognathic surgery, planned using either the CASS method or the modified CASS method. Linear and angular discrepancies between the VSP outcome and postoperative outcome for both groups were compared for maxilla, mandible, and chin segments. Aside from the comparison between both groups, additional criteria were used to determine the accuracy of the protocol based on a linear and angular difference between planned and actual outcomes of less than 2 mm and 4°, respectively. The intergroup comparisons were performed by one-way ANOVA, with the level of significance set at 5%.

RESULTS

A total of 21 patients, of both genders, were assigned into group I (n = 11), planned with the CASS method, and group II (n = 10), planned with the modified CASS method. Both the CASS and modified CASS methods presented similar accuracy with regard to linear differences for the maxilla, mandible, and chin segments, except for ΔX for the mandibular segment, where the modified CASS method showed slightly better accuracy. However, there was a statistically significant difference with regard to angular differences in the chin segment, with the CASS method shown to be the more accurate. Aside from Δpitch for the chin segment, no linear or angular differences exceeded 2 mm or 4°.

CONCLUSION

Although statistically significant differences were found with regard to angular measurements in the chin segment, the accuracy of the modified CASS method for virtual planning can be considered as clinically equivalent, with a performance comparable to that of the CASS method.

Accuracy of virtual planning in orthognathic surgery: a systematic review

BACKGROUND

The elaboration of a precise pre-surgical plan is essential during surgical treatment of dentofacial deformities. The aim of this study was to evaluate the accuracy of computer-aided simulation compared with the actual surgical outcome, following orthognathic surgery reported in clinical trials.

METHODS

Our search was performed in PubMed, EMBASE, Cochrane Library and SciELO for articles published in the last decade. A total of 392 articles identified were assessed independently and in a blinded manner using eligibility criteria, out of which only twelve articles were selected for inclusion in our research. Data were presented using intra-class correlation coefficient, and linear and angular differences in three planes.

RESULTS

The comparison of the accuracy analyses of the examined method has shown an average translation (< 2 mm) in the maxilla and also in the mandible (in three planes). The accuracy values for pitch, yaw, and roll (°) were (< 2.75, < 1.7 and < 1.1) for the maxilla, respectively, and (< 2.75, < 1.8, < 1.1) for the mandible. Cone-beam computed tomography (CBCT) with intra-oral scans of the dental casts is the most used imaging protocols for virtual orthognathic planning. Furthermore, calculation of the linear and angular differences between the virtual plan and postoperative outcomes was the most frequented method used for accuracy assessment (10 out of 12 studies) and a difference less than 2 mm/° was considered acceptable and accurate. When comparing this technique with the classical planning, virtual planning appears to be more accurate, especially in terms of frontal symmetry.

CONCLUSION

Virtual planning seems to be an accurate and reproducible method for orthognathic treatment planning. However, more clinical trials are needed to clearly determine the accuracy and validation of the virtual planning in orthognathic surgery.

Comparison of three different types of splints and templates for maxilla repositioning in bimaxillary orthognathic surgery: a randomized controlled trial

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±0.66mm) when compared to both the CROS group (2.55±0.95mm, P<0.05) and DOS group (2.15±1.12mm, 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.

Three-dimensional accuracy of virtual planning in orthognathic surgery

INTRODUCTION

This study aimed to assess the accuracy of virtual surgical planning (VSP) performed by Dolphin Imaging software (version 11.9; Dolphin Imaging and Management Solutions, Chatsworth, Calif).

METHODS

Ten people requiring bimaxillary surgery and genioplasty were followed up prospectively. All patients had preoperative cone-beam computed tomography, plaster models, and photographs allowing for VSP. Interocclusal intermediate surgical splints were produced using a 3-dimensional (3D) printer. Postoperative images were acquired 15 days after surgery using cone-beam computed tomography. ITK-Snap (version 3.6; Cognitica, Philadelphia, Pa) allowed the segmentation of reliable 3D models. Geomagic Qualify 2013 (3D Systems, Rock Hill, SC) and MeshValmet (version 3.0) were used to identify the differences between VSP and actual surgical results through the root mean square values and the 3D translational displacement (3-axes) of the 3D centroid of each model.

RESULTS

Discrepancies between the VSP and the actual result were found at the mandible (P = 0.013) and the chin (P = 0.013) when considering the root mean square values. In addition, 3D centroid differences were found in the transverse and sagittal direction of the right ramus (P = 0.034 and P = 0.005, respectively) and the sagittal aspect of the left ramus (P = 0.025). Considering 2 mm as a threshold of clinical relevance, almost all the bone fragments (maxilla, proximal, and distal mandibular segments) were accurately corrected by surgery, although not in the chin.

CONCLUSIONS

On the basis of the obtained values, it is possible to consider the Dolphin Imaging software as clinically acceptable for performing virtual orthognathic surgical planning.

Orthodontic and surgical management of a patient with severe mandibular deficiency and asymmetry with condylar hypoplasia using 3-dimensional surgical planning in combination with a modified surgery-first approach

Progressive improvements in digital technology and surgical techniques have synergized the speed, predictability, and favorable outcomes for patients undergoing surgical-orthodontic treatment with handicapping dentofacial deformities. This case report will demonstrate the management of a patient with severe mandibular hypoplasia, condylar hypoplasia, and mandibular asymmetry. The dentofacial deformity, and consequently, the unaesthetic facial appearance, led to psychosocial stress, symptoms of excessive daytime sleepiness, and functional limitations, especially related to mandibular movements. A modified surgery-first approach was used, which was successfully performed using computer-assisted surgical planning. Postsurgical orthodontics was accomplished with the aid of temporary skeletal anchorage mini-plates. An additional alloplastic enhancement of the chin addressed the severe microgenia, which the osseous advancement could not achieve. This resulted in a total advancement of the pogonion by 26 mm yielding a remarkable improvement in the patient's facial esthetics. Furthermore, a considerable improvement in mandibular function and reduction in daytime sleepiness occurred. The severe malocclusion with a discrepancy index value of 47 was treated to a successful final occlusion in 21 months of treatment time.

Orthognathic Hardware Complications in the Era of Patient-Specific Implants

BACKGROUND

Patients undergoing orthognathic skeletal correction present with a variety of comorbidities that may affect surgical outcomes. The purpose of this study was to determine how patient risk factors and operative technique contribute to complication rates after orthognathic surgery in the era of patient-specific implants.

METHODS

Retrospective cohort analysis was conducted of pediatric patients undergoing Le Fort I osteotomy, bilateral sagittal split osteotomy, and/or genioplasty from 2014 to 2018. Patient risk factors, operative characteristics, and postoperative outcomes were gathered and compared with appropriate statistics.

RESULTS

Ninety-four patients met inclusion criteria, with an overall 1-year complication rate of 11.7 percent (11 of 94). Patient-specific mandibular plates are significantly associated with infection (p = 0.009; OR, 8.8), occurrence of any complication (p = 0.003; OR, 8.3), readmission (p < 0.001; OR, 11.1), and reoperation (p < 0.001; OR, 11.4). In patients with syndromes or history of cleft lip/palate, patient-specific mandibular plates are associated with infection (p = 0.006; OR, 10.3), readmission (p < 0.001; OR, 21.6), and reoperation (p < 0.001; OR, 22.9). In multivariate regression controlling for age, sex, syndrome status, and orofacial cleft history, use of patient-specific mandibular plates was associated with infection (p = 0.017; adjusted OR, 12.5), any complication (p = 0.007; adjusted OR, 11.8), readmission (p = 0.001; adjusted OR, 17.9), and reoperation (p = 0.001; adjusted OR, 18.9).

CONCLUSIONS

In the era of patient-specific orthognathic surgery, syndromic status and use of patient-specific mandibular plates are associated with increased infection, readmission, and reoperation because of hardware-related complications. The authors' data support increased caution and counseling with use of patient-specific mandibular implants in patients with syndromic status, history of orofacial cleft, and history of previous maxillomandibular surgery given increased risk of hardware-related complications.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Digital Image Analyses of Preoperative Simulation and Postoperative Outcome following Blepharoptosis Surgery

Background

Before blepharoptosis surgery, simulation of eyelid features, including lid height and crease position, is often performed. However, discrepancies of the simulation and outcome can occur. The purpose of this study was to analyze the pre- and postoperative images and to evaluate factors contributing to the discrepancies.

Methods

Forty-one involutional blepharoptosis patients (68.2 ± 7.1 years) underwent levator aponeurosis advancement. A semicircular bent wire was used to push the preoperative ptotic eyelid up to simulate the postoperative appearance of the eyelid. Digital images of the simulation were compared with the appearance at 3 months after the surgery. The ImageJ software was used to analyze the pre- and postoperative margin reflex distance-1 (MRD-1), pretarsal show (PTS), fissure height (FH), and ocular surface area (OSA). Factors with a potential of affecting the predictability of simulation were determined.

Results

During simulation, the MRD-1 was 3.6 ± 0.4 mm, the PTS was 3.48 ± 1.2 mm, the FH was 8.5 ± 0.9 mm, and the OSA was 120.7 ± 22.3 mm². After the surgery, the corresponding values were 3.3 ± 1.2 mm, 3.3 ± 1.5 mm, 8.6 ± 1.4 mm, and 119.1 ± 25.1 mm², respectively. The postoperative MRD-1 was significantly smaller than that of the simulation (P = 0.005, paired t test). The MRD-1 simulation error was positively correlated with the length and width of the skin resection (all P < 0.05), and the PTS error was positively correlated with the length of the skin resection (r = 0.332, P = 0.031) and negatively correlated with the preoperative OSA (r = -0.588, P = 0.007).

Conclusions

The postoperative appearance of the eyelid can be simulated fairly accurately by pushing up the upper eyelid with a curved wire. However, the MRD-1 tended to be overestimated, especially for cases requiring a large skin resection.