Evaluation of facial soft tissue asymmetric changes in Class III patients after orthognathic surgery using three-dimensional stereophotogrammetry

The aim of this study was to investigate changes in facial soft tissue asymmetry over time after orthognathic surgery in Class III patients using three-dimensional stereophotogrammetry. The study included 101 patients with a skeletal Class III malocclusion (72 female, 29 male; age range 19–53 years, mean age 28.6 years) who underwent orthognathic surgery. The minimum follow-up was 12 months. Three-dimensional photographs were acquired using the 3dMDtrio stereophotogrammetry system, and 21 anthropometric landmark positions were evaluated at three time points: before surgery (T0), 6 months (T1) and 12 months (T2) after surgery. Facial asymmetry was assessed and classified as follows: 0–2 mm, mild; 2–5 mm, moderate;> 5 mm, severe. The average distance for whole face asymmetry differed between T0 (median 0.76 mm) and T1 (median 0.70 mm); however, there was no statistically significant difference at any time point. The chin volume asymmetry score differed significantly between T0 (median 1.11 mm) and T1 and T2 (median 1.08 mm for both; P < 0.001 and P = 0.001, respectively), but not between T1 and T2 (P = 0.061). The study findings indicate that the asymmetry of the facial soft tissues has the potential to return after 6 months, without reaching the baseline.     

An innovative universal protocol for orthognathic surgery three-dimensional virtual simulation

The aim of this technical note is to describe a protocol for three-dimensional virtual simulation of orthognathic surgery that has been designed to be easily implemented, without the need for any special clinical apparatus, software brand, or computed tomography sequence. The protocol comprises innovative concepts and simplified steps for image segmentation, creation of a composite skull, control of the condylar position, and sequencing of bimaxillary surgery. This protocol was applied by the developers in about 2000 cases performed between 2015 and 2022, and has become quite popular among local surgeons. Previous preliminary studies have shown that it meets the accuracy standards for clinical use, although further studies with larger numbers of patients are desirable for additional validation.     

Posterior bending osteotomy: An effective measure to secure facial symmetry in orthognathic surgery

This study aimed to compare the effectiveness of posterior bending osteotomy and grinding techniques for orthognathic surgery in patients with facial asymmetry. Patients who had undergone Le Fort I osteotomy and bilateral sagittal split ramus osteotomy, and who presented with a menton shift and setback difference exceeding 4 mm, were enrolled. Cone-beam computed tomography was performed before surgery (T0), immediately after surgery (T1), and 6 months after surgery (T2). Overall, 38 patients were included and divided into posterior bending osteotomy (n = 23) and grinding (n = 15) groups.Significant differences were observed between the posterior bending osteotomy and grinding groups on the treated side. In the grinding group, the gonion on the treated side was displaced slightly outward, resulting in a significant difference between both sides (non-treated side: 50.52 ± 4.20 [T0] and 48.67 ± 4.37 [T2]; treated side: 50.88 ± 4.55 [T0] and 51.00 ± 3.95 [T2]; p = 0.038). In the posterior bending osteotomy group, bilateral inward movements of the gonion were observed, and the distance from the midsagittal plane to the gonion did not differ significantly between the sides (non-treated side: 46.74 ± 4.41 [T0] and 45.54 ± 3.95 [T2]; treated side: 47.43 ± 4.93 [T0] and 45.18 ± 3.52 [T2]; p = 0.224). The yawing movement of the proximal segment was greater in the grinding group than in the posterior bending osteotomy group (non-treated side: p = 0.839; treated side: p = 0.025).Posterior bending osteotomy is recommended over the grinding method for patients with severe facial asymmetry, in order to ensure a symmetric and esthetic facial profile by allowing passive adaptation between the mandibular segments.     

Soft tissue response and facial symmetry after orthognathic surgery

ObjectiveIn orthognathic surgery aesthetic issues and facial symmetry are vital parameters in surgical planning. Aim of this investigation was to document and analyze the results of orthognathic surgery on the base of a three-dimensional photogrammetric assessment, to assess the soft tissue response related to the skeletal shift and the alterations in facial symmetry after orthognathic surgery.Patients and methodsIn this prospective clinical trial from January 2010 to June 2011, 104 patients were examined who underwent orthognathic surgery due to mono- or bimaxillary dysgnathia. The standardized measurements, based on optical 3D face scans, took place one day before orthognathic surgery (T1) and one day before removal of osteosynthesis material (T2).ResultsSoft tissue changes after procedures involving the mandible showed significant positive correlations and strong soft tissue response (p < 0.05). The midfacial soft tissue response after maxillary advancement was only of minor extent (p > 0.05). The facial surfaces became more symmetric and harmonic with the exception of surgical maxillary expansion, but improvement of facial symmetry revealed no statistical significance.ConclusionSoft tissue response after orthognathic surgery and symmetry are only partially predictable, especially in the maxillary and midfacial region. Computer programs predicting soft tissue changes are not currently safely reliable and should not be used or with caution to demonstrate a patient potential outcome of surgery.     

Three-dimensional evaluation of soft-tissue response to osseous movement after orthognathic surgery in patients with facial asymmetry: A systematic review

To systematically assess the current literature on soft-tissue response associated with osseous movement following orthognathic surgery in patients with facial asymmetry.Six electronic databases (PubMed, EMBASE (via Ovid), Medline (via Ovid), Cochrane Library, Scopus, and Web of Science) and gray literature were searched for studies evaluating hard- and soft-tissue responses three-dimensionally after orthognathic surgery, using MeSH terms and keywords. The methodological quality and level of evidence of the included studies were analyzed using EPHPP and GRADE, respectively.The primary search yielded 125 articles, and 10 articles that satisfied the predefined inclusion criteria were finally included. All the included articles evaluated soft-tissue response, with six of them additionally investigating the magnitude of this response. Soft tissues move with hard tissues horizontally and anteroposteriorly; however, soft-tissue movement is less than hard tissue movement. In addition, soft tissue movement is more pronounced in the lower central facial region. Six articles were judged as having ‘strong’ methodological quality, while the evidence was found to be of ‘low’ quality for the soft-tissue response and the magnitude of this response.Despite a low level of evidence, the review substantiates a favorable three-dimensional soft-tissue response following osseous surgery. The soft-tissue response is more pronounced horizontally, anteroposteriorly, and in the lower central facial region. Nevertheless, well-designed prospective studies with a higher level of evidence are needed.     

Computer-assisted orthognathic surgery for correction of facial asymmetry: results of a randomised controlled clinical trial

In this randomised controlled clinical trial, 2 homogeneous groups of patients with facial asymmetry (n = 10 in each) were treated by either classic or computer-assisted orthognathic corrective surgery. Differences between the 2 groups in the alignment of the lower interincisal point (p = 0.03), mandibular sagittal plane (p = 0.01), and centring of the dental midlines (p = 0.03) were significant, with the digital planning group being more accurate.     

Stability of lingual plate osteotomy in orthognathic surgery for patients with severe facial asymmetry: A retrospective analysis with 1-year follow-up

This study aimed to evaluate the stability of lingual plate osteotomy after sagittal split ramus osteotomy (SSRO) in patients with severe facial asymmetry. It included 20 patients undergoing lingual plate osteotomy between January 2011 and January 2017. Cephalometric X-ray imaging and three-dimensional computed tomography (3DCT) were performed before the operation and then 1 day and 1 year after the operation. The relapse rate and postoperative complications were assessed. The operation time was compared between lingual plate osteotomy and transoral angle osteotomy.Specific values measured on cephalometric X-ray and 3DCT images showed significant changes 1 day after the operation, with 47.9% correction occurring in the occlusal plane angle (mean ± SD = 1.74 ± 0.84°, p < 0.05). However, no significant differences were found between measurements taken 1 day and 1 year after the operation, with a 5% change seen in the occlusal plane angle (mean ± SD = 0.1 ± 0.24°, p = 0.61), suggesting that the surgical outcomes can be well maintained for at least 1 year after surgery.Three patients experienced numbness postoperatively but recovered within 1 year. The operation time for lingual plate osteotomy was shorter than that for transoral angle osteotomy. Our findings indicate that lingual plate osteotomy after SSRO is stable, effective, and safe in patients with severe facial asymmetry.     

Mandibular asymmetries and associated factors in orthodontic and orthognathic surgery patients

Objectives:To estimate the prevalence of mandibular asymmetries in orthodontic and orthognathic surgery patients and to investigate demographic and skeletal factors associated with this disharmony.Materials and Methods:Cone-beam computed tomography images of 1178 individuals aged 19 through 60 years with complete dentitions were analyzed. Outcomes were classified as relative mandibular symmetry, moderate asymmetry, and severe asymmetry. Factors recorded included sex, age, side of mandibular deviation, sagittal jaw relationship, vertical skeletal pattern, angle of the cranial base, and maxillary asymmetry. Ordinal logistic regression was used to estimate simple and adjusted odds ratios (OR) for the individuals with moderate and severe mandibular asymmetry, as well as 95% confidence intervals.Results:Prevalence values of 55.2%, 27.2%, and 17.6% were observed for relative mandibular symmetry, moderate asymmetry, and severe asymmetry, respectively. An independent association with the side of mandibular deviation and the presence of maxillary asymmetry was observed, both for subjects with moderate mandibular asymmetry (left side: OR = 1.50; 95% CI: 1.01–2.24 / maxillary asymmetry: OR = 2.07; 95% CI: 1.11–3.76) and for those with severe asymmetry (left side: OR = 2.09; 95% CI: 1.27–3.44 / maxillary asymmetry: OR = 4.93; 95% CI: 2.64–9.20).Conclusions:Moderate and severe mandibular asymmetries were present in 44.8% of the sample, being associated with the side of mandibular deviation and with maxillary asymmetry.     

Surgery-first orthognathic approach for the correction of facial asymmetry

We aimed to compare the reliability of the surgery-first approach and the traditional orthodontic-first approach for the correction of facial asymmetry based on the new classification of facial asymmetry.Patients with facial asymmetry who underwent orthognathic surgery between January 2016 and January 2019 were included. Cephalometric changes and relapse ratios were analyzed 12 months before and after surgery. Patients were divided into horizontal and vertical asymmetry groups based on the asymmetry vector, and subgroup analysis was conducted.The surgery-first approach without presurgical orthodontic treatment and the orthodontic-first approach showed a similar degree of asymmetry correction and skeletal stability. The relapse ratios of the maxilla height in the surgery-first and orthodontic-first groups were 0.25 ± 0.21 and 0.27 ± 0.25, respectively (p = 0.63), the relapse ratios of the maxilla width were 0.31 ± 0.32 and 0.21 ± 0.2, respectively (p = 0.14), the mandibular height relapse ratios were 0.34 ± 0.58 and 0.29 ± 0.36, respectively (p = 0.69), and the mandibular width relapse ratios were 0.12 ± 0.22 and 0.26 ± 0.31, respectively (p = 0.058). The treatment period of the surgery-first group (18.5 ± 5.3 months) was significantly shorter than that of the orthodontic-first group (22.9 ± 7.5 months, p = 0.024). Among the surgery-first group, patients with vertical asymmetry (15.0 ± 3.2 months) had a shorter treatment than those with horizontal asymmetry (21.6 ± 6.8 months, p = 0.006).Although contesting traditional standards is always challenging, the surgery-first orthognathic approach may lead to a new era in traditional orthognathic approaches. This new classification of facial asymmetry could be useful and practical when treating patients with facial asymmetry regardless of the etiology.     

Three-dimensional assessment of functional change following Class 3 orthognathic correction - A preliminary report

Orthognathic surgery is a well-documented clinical procedure for patients who complain of functional and aesthetic problems related to dento-facial imbalance. The aims of treatment are to establish facial harmony, normalise function and maximise the stability of the outcome. Conventional diagnostic aids to treatment include plain film radiographs and photographs which provide a static analysis of the facial structures at a particular point in time. Functional assessment of facial movement is rarely performed but could have important implications on the stability of the surgery through post-surgical soft tissue adaptation to the new skeletal relationships. A case report is presented for which novel three-dimensional motion analysis techniques were used to assess facial movement through the surgical correction of a Class 3 malocclusion. It was found that facial movement increased for all circum-oral postures post-surgery. Future research in this field recommends collection of data from a control group to allow comparisons of facial movement between different surgical samples.     

Masseter muscle changes following orthognathic surgery: A long-term three-dimensional computed tomography follow-up

Objective:To evaluate the long-term changes of masseter muscle morphology in skeletal Class III patients with facial asymmetry following two-jaw orthognathic surgery (Le Fort I osteotomy + intraoral vertical ramus osteotomy).Materials and Methods:Using computed tomography (CT), a longitudinal study was conducted on 17 skeletal Class III patients with facial asymmetry. Measurements from the reconstructed three-dimensional (3D) CT images were compared from T1 (before surgery), T2 (1 year after surgery), and T3 (4 years after surgery). The maximum cross-sectional area (CSA), orientation, thickness, and width of the masseter muscle were measured on both the deviated and nondeviated sides. The control group included 17 volunteers with skeletal and dental Class I relationships without dentofacial deformities.Results:At T1, there were no significant differences in CSA, thickness, or width of masseter muscle between the deviated and nondeviated sides. Masseter muscle orientation was significantly more vertical on the nondeviated side than on the deviated side at T1 (P < .01); no significant bilateral differences were noted at T2 and T3. At T1, masseter muscle measurements were significantly lower than controls (P < .01). During T1–T3, a significant increase was noted in CSA, thickness, and width (P < .01) of masseter muscle. At T3, no significant difference was noted between the study and control groups.Conclusion:After surgery, the masseter muscle measurements of skeletal Class III asymmetry patients showed no significant differences compared with the control group within the 4-year follow-up period, indicating adaptation to the new skeletal environments and increased functional demand.     

Facial palsy after orthognathic surgery: A systematic review

It was the aim of the systematic review to evaluate the incidence of facial palsy following orthognathic surgery, and to assess the possible mechanisms of injury, subsequent management, and eventual outcomes. The protocol of this systematic review was registered in the International Prospective Register of Systematic Reviews. A thorough search of PubMed, Scopus, Cochrane Library, and CINAHL databases up to April 2022 was conducted. In total, 34 articles were selected for this review, including 54 facial palsies in 53 patients. The incidence of facial palsy was estimated to range from 0.04% to 0.77%. Most of the possible etiologies proposed involved intraoperative nerve compression or postoperative edema. Physical therapy and steroid administration were the most frequently employed management approaches. Surgical exploration for the facial nerve was executed in one patient. Forty-three facial palsies (79.6%) attained complete recovery with conservative management, whereas 11 facial palsies (20.4%) continued to show incomplete recovery during the follow-up period. Earlier facial palsy onset (timing after surgery) was related to a higher risk of continuing palsy (p = 0.018). Within the limitations of this review it seems that facial palsy following orthognathic surgery should be treated conservatively whenever appropriate.     

Barcelona line. A multicentre validation study of a facial projection reference in orthognathic surgery

The purpose of this study was to validate an already published facial anteroposterior reference: upper incisor (UI) to soft tissue plane or so-called Barcelona line (BL) to trace the most aesthetic sagittal position of the maxilla. A cross-sectional multicentre evaluation of Caucasian patients from Spain and Brazil with different anteroposterior maxillary positions was designed. Sagittal images in natural head orientation of grouped patients according to the horizontal distance from the UI to BL were ranked by healthcare professionals and non-professional Caucasian raters according to the aesthetic perception of each profile, using a digital survey. Seventy-four raters (50 laypeople, 12 orthodontists, and 12 maxillofacial surgeons) rated 40 profiles. The best-rated profile corresponded to group 3 (0–4 mm UI-BL) with 61.8% of positive evaluations, followed by group 4 (≥ 4 mm UI-BL): with 61.1%. On the other hand, group 1 (≤?4 mm UI-BL) was the worst-ranked profile with 71.8% of negative evaluations, followed by group 2 (?4–0 mm UI-BL): with 59.6% of negative evaluations. The correlation between the mean assessment score and UI-BL showed a moderately-strong association (r = 0.68, p < 0.001). The inter-rater reliability of assessment (74 evaluators) was moderate (k = 0.49, 95% CI: 0.39 to 0.59). The results suggest that protrusive middle-third facial profiles are preferable. The BL is proposed as a simple, individualised, and reproducible tool to trace an aesthetic sagittal position of the maxilla in orthognathic surgery.     

Cone beam computed tomography volumetric airway changes after orthognathic surgery: a systematic review

The aim of this systematic review was to provide a structured overview of three-dimensional airway volume changes in relation to various orthognathic surgeries. Clinical human studies performing pre- and postoperative three-dimensional airway volume assessments to investigate volumetric changes of the airway after orthognathic surgery were included. Pre-determined inclusion and exclusion criteria were applied in an extensive search of the PubMed, Embase, and Web of Science electronic databases. The cut-off date was set to January 1, 2022. Forty-one articles reporting retrospective and prospective case–control and case series studies were included. All studies were determined to be of medium quality (moderate risk of bias). The included studies were categorized by type of intervention. Pre- and postoperative volumes were extracted from the available data, and volume changes as a percentage of the preoperative levels were calculated. Isolated mandibular setback surgery generally decreased the airway volume. Isolated maxillary or mandibular advancement, bimaxillary advancement, and surgically assisted maxillary expansion generally increased the airway volume in the total airway and oropharynx, among which the effect of bimaxillary advancement surgery appeared most significant. High heterogeneity exists in the terminology and definitions of the airway and its segments. A more uniform methodology for airway volume measurement is needed to provide an insight into the impact on the airway of specific types of surgical intervention. In conclusion, airway volumes are affected after orthognathic surgery, which may be of clinical significance, especially in patients who are predisposed to obstructive sleep apnoea.     

改良双侧下颌支矢状劈开术固定法在矫正面部不对称畸形中的初步应用

目的: 研究双侧下颌支矢状劈开术(BSSRO)中保留凹陷侧近心端骨板联合双皮质螺钉固定法在矫正面部不对称畸形中应用价值。方法：选择2013年1月—2013年7月间在上海交通大学医学院附属第九人民医院行正颌手术治疗的8例成年偏突颌畸形患者作为研究对象,术前进行临床检查和三维CT检查,确定双侧咬肌区的不对称情况,术中常规行BSSRO和(或)上颌骨Le Fort I型截骨术。在下颌骨旋转后退后,肥大侧去除近心端多余骨板行4孔小钛板固定,凹陷侧保留近心端多余骨板用双皮质螺钉固定。术后3个月检查患者面部对称性的改善情况,并通过正位片测量、计算患者手术前、后两侧结构的对称性,评估该方法的有效性。利用SPSS 20.0 软件包对数据进行配对t检验。结果：8例患者的面部不对称性均得到很好改善,未出现钛钉脱落、骨块移位和复发等情况。手术前、后患者面部对称性相关指标的差值具有统计学意义(P<0.05)。结论：BSSRO中保留凹陷侧近心端骨板联合双皮质螺钉固定法能更有效地矫正面部不对称畸形,可安全应用。     

Appearance on face reading (cheek line) after orthognathic surgery

The cheek line (face reading) is an aesthetic element of the facial profile. The purpose of our study was to investigate the changes in the cheek line after mandibular setback surgery. Forty patients (20 female and 20 male, mean (SD) age 22 (5) years) were diagnosed with mandibular prognathism and treated by intraoral vertical ramus osteotomy alone. Cephalograms were obtained before operation (T1), at least a year postoperatively (T2), and final surgical changes over a year (T2-T1). The cheek line and landmarks (soft and hard tissues) were compared using the paired t test. The hypothesis was that the cheek line did not change significantly after mandibular setback. At the time of the final follow-up (T2-T1), the mean (SD) horizontal setback of pogonion (Pog) was 12.3 (3.5) mm for women and 11.7 (4.3) mm for men. The ratios of soft:hard tissue, labrale inferius:incisor inferius, labiomental sulcus:point B, soft tissue Pog:Pog, and cheek point:Pog in women were 0.96, 0.98, 0.98, and 0.08, and in men 0.91, 1.01, 0.94, and 0.13, respectively. The nasolabial and cervicomental angles in women were significantly increased by 11.1° and 11.4°, respectively, and in men the nasolabial angle was significantly increased by 11.1° and the mentolabial angle reduced by 9.9°. The cheek line (T2-T1) was moved significantly forwards. The hypothesis was therefore rejected. In conclusion, the cheek line was advanced significantly after isolated mandibular setback.     

正颌外科计算机辅助诊断、模拟手术及面像预测系统准确性研究

目的评价计算机专家预测系统的预测准确性及其临床应用的意义和价值。方法通过应用正颌外科专家预测系统（ｏｒｔｈｏｇｎａｔｈｉｃｓｕｒｇｅｒｙｐｒｅｄｉｃａｔｉｏｎｅｘｐｅｒｔｓｙｓｔｅｍ，ＯＳＰＥＳ）对临床３１例牙颌面畸形患者进行了术前诊断，模拟手术和面像预测。结果本系统能够较为准确的预测术后治疗效果，单颌手术平均总准确率达９５％以上，双颌手术达８５％以上。对硬组织预测较软组织预测更为准确。并对影响计算机专家预测系统准确性的因素等进行了讨论。结论计算机专家预测系统是正颌外科预测分析的有价值的工具。     

Enhanced recovery after orthognathic surgery: a retrospective comparison study of 56 patients

Enhanced Recovery After Surgery (ERAS) protocols have been demonstrated to expedite recovery and decrease hospital stay from multiple surgical specialties. This study sought to determine how an ERAS protocol would improve patient outcomes with regards to inpatient postoperative nausea, vomiting, and pain scores following orthognathic surgeries. This was a retrospective study comparing patients who underwent orthognathic surgery with and without an ERAS protocol. The primary measurables included opioid consumption, antiemetic medical consumption, nausea and vomiting incidences, and pain scores between the two groups during their hospital stays. A total of 56 patients were retrospectively analysed comparing ERAS protocol to non-ERAS protocol. The maximum pain score of the ERAS group was 5.50 out of 10 compared to the control group of 7.50 out of 10 (p<0.001). Morphine equivalent consumption during their time in the ward was statistically significant (51.4 mg control versus 9.4 mg ERAS group). ERAS protocol is safe and effective for decreasing postoperative pain and nausea. The ERAS protocol is not only applicable for orthognathic surgery but should be highly considered for other maxillofacial surgeries.     

The effect of orthognathic surgery on temporomandibular disorder

This study aimed to evaluate the difference in prevalence of temporomandibular disorder (TMD) before and after orthognathic surgery (OGS), particularly in patients with mandibular asymmetry.A prospective cohort study of patients undergoing corrective orthognathic surgery was conducted. Pre-operative and post-operative (3 months, 6 months and 1 year) TMD assessment were performed according to the Diagnostic Criteria for TMD (DC/TMD) protocol.64 patients were included in the study. Overall, there was a significant reduction of 26.5% in TMD prevalence from 60.9% pre-operatively to 34.4% 1-year post-operatively (p = 0.003). In all, 37.5% of patients had their TMD condition treated, 50% had no change in their symptoms while 12.5% experienced a worsening of their symptoms. No significant difference in terms of change in TMJ status was observed among the different ramus procedures, the type and magnitude of mandibular movement, skeletal class, and presence of mandibular asymmetry.In conclusion, it appears that corrective orthognathic surgery for dentofacial deformities might provide a secondary benefit of treating TMD. However, surgeons have to be aware that a small percentage of patients might experience a deterioration of their TMD condition, and that those who were previously asymptomatic may develop TMD symptoms after surgery.     

A new model of customized maxillary guide for orthognathic surgery: Precision analysis

PurposeTo evaluate the surgical accuracy of a new Maxillary Bone-Dental-Supported guide (MBDS) for osteotomy and maxillary positioning in orthognathic surgeries.Materials and methodsThe customized MBDS were prototyped through CAD-CAM technology (computer-aided design and manufacturing). The planning image (CT0) was superimposed on the computed tomography scan post-treatment (CT1) and the mean of positional differences between them were obtained tridimensionally at the axes: mediolateral (X), anteroposterior (Y) and vertical (Z).ResultsEleven patients were selected according to the inclusion and exclusion criteria. The mediolateral movement showed the best precision, with a greater mean difference of 0.34 mm at the CI point (central incisor) and less than 0.02 mm at the RM point (right molar). In the vertical direction, the largest mean discrepancy found was 0.50 mm and on the y-axis, anteroposterior, was 0.74 mm, as well as two at the CI point. The skeletal SNA point, on the other hand, showed the smallest average discrepancies: 0.10 mm (x-axis), 0.03 mm (y-axis) and 0 mm (z-axis). Overall, 99.24% of the discrepancies found were less than 2 mm.ConclusionOur results suggests that the double support, osseous and dental, present in that new guide, favored the positional stability of the maxilla and promoted better control of its vertical axis. Furthermore, the function of an osteotomy guide increases the predictability and security of the surgical procedure.