Mandible-first sequence in bimaxillary orthognathic surgery: a systematic review

Mandibular autorotation: a critical virtual parameter in clinical decision-making regarding maxilla-first versus mandible-first sequence

Large degrees of mandibular autorotation during intermediate splint design are prone to transfer error and decrease accuracy. The purpose of this study was to evaluate the amount of mandibular autorotation necessary to design intermediate splints for maxilla- and mandible-first sequences using virtual planning software, to help the clinical decision-making regarding the most adequate sequence for each patient. The influence of specific orthognathic movements (different vertical and sagittal changes at the Le Fort I level, cant correction) and the type of maxillofacial deformity (skeletal Class II, III, anterior open bite) were evaluated to identify those that would require higher levels of autorotation for each sequence. Three-dimensional virtual surgical planning data of 194 patients were reviewed (126 female, 68 male; mean age 26.5 ± 11.0 years; 143 skeletal Class II, 51 skeletal Class III) and subgroup analyses were conducted using the Kruskal-Wallis test and post-hoc pairwise comparisons. As an additional parameter (mandibular autorotation), maxilla-first is indicated for bimaxillary osteotomies with Le Fort I posterior intrusion, anterior open bite, and skeletal Class III, while mandible-first is recommended for Le Fort I global extrusion, especially with maxillary cant correction.

Accuracy of patient-specific implants versus CAD/CAM splints with the mandible-first approach in bimaxillary orthognathic surgery for skeletal Class II malocclusion

This retrospective study aimed to compare the accuracy of patient-specific implants (PSI) versus mandible-first computer-aided design and manufacturing (CAD/CAM) splints for maxilla repositioning in orthognathic surgery of skeletal Class II malocclusion patients. The main predictor was the surgical method (PSI vs. splints), with the primary outcome being the discrepancy in maxilla centroid position, and secondary outcomes being translation and orientation discrepancies. A total of 82 patients were enrolled (70 female, 12 male; mean age 25.5 years), 41 in each group. The PSI group exhibited a median maxillary position discrepancy of 1.25 mm (interquartile range (IQR) 1.03 mm), significantly lower than the splint group's 1.98 mm (IQR 1.64 mm) (P < 0.001). In the PSI group, the largest median translation discrepancy was 0.74 mm (IQR 1.17 mm) in the anteroposterior direction, while the largest orientation discrepancy was 1.83° (IQR 1.63°) in pitch. In the splint group, the largest median translation discrepancy was 1.14 mm (IQR 1.37 mm) in the anteroposterior direction, while the largest orientation discrepancy was 3.03° (IQR 2.11°) in pitch. In conclusion, among patients with skeletal Class II malocclusion, the application of PSI in orthognathic surgery yielded increased precision in maxillary positioning compared to mandible-first CAD/CAM splints.

On the feasibility of minimally invasive Le Fort I with patient-specific implants: Proof of concept

A novel approach to Le Fort I osteotomy is presented, integrating patient-specific implants (PSIs), osteosynthesis and cutting guides within a minimally invasive surgical framework, and the accuracy of the procedure is assessed through 3D voxel-based superimposition. The technique was applied in 5 cases. Differences between the surgical plan and final outcome were evaluated as follows: a 2-mm color scale was established to assess the anterior surfaces of the maxilla, mandible and chin, as well as the condylar surfaces. Measurements were made at 8 specific landmarks, and all of them showed a mean difference of less than 1 mm. In conclusion, the described protocol allows for minimally invasive Le Fort I osteotomy using PSIs. Besides, although the accuracy of the results may be limited by the small sample size, the findings are consistent with those reported in the literature. A prospective comparative study is needed to obtain statistically significant results and draw meaningful conclusions.

Exploring the relationship between the number of systematic reviews and quality of evidence: an orthognathic surgery-based study

OBJECTIVE

We analyzed the quality and quantity of systematic reviews (SRs) of orthognathic surgery, the most frequently published topic in maxillofacial surgery.

STUDY DESIGN

We searched the PubMed database for SRs of orthognathic surgery with no restriction on the language of publication date. We assessed the certainty of evidence presented according to the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocol and the Leiden Manifesto using the Grading of Recommendations Assessment, Development, and Evaluation approach. We analyzed the data using descriptive statistics, Pearson´s correlation test, and linear regression.

RESULTS

Of the 171 SRs evaluated, approximately one fifth presented evidence with a high level of certainty. The number of orthognathic surgery SRs has been increasing, and many SRs were published after very similar topics had already been published. There is no relationship between the impact factor and the certainty of evidence.

CONCLUSIONS

An excessive number of SRs of orthognathic surgery are published, and many SRs are superfluous, simply reporting previous findings. Clinicians should not base treatment decisions solely on the evidence presented in SRs, and journal editors and reviewers should evaluate these SRs more critically, particularly when they address topics that have already been covered in the literature.

Mandible-First Sequencing Increase Surgical Accuracy for Patients With Skeletal Class II Malocclusion Concomitant With Unstable Condyle-Fossa Relation

The aim of this study was to explore whether mandible-first sequencing increases the surgical accuracy in bimaxillary orthognathic surgery for patients with skeletal class II malocclusion concomitant with the unstable condyle-fossa relation. A retrospective evaluation of 19 patients who had undergone virtually planned double-splint orthognathic surgery with different operation sequences was performed: maxilla-first (n=9) or mandible-first (n=10) surgery. The centroid position, translational, and rotational differences in the maxilla were evaluated by comparing the virtual plans with actual results. The stability was assessed by comparing the actual results with the follow-up outcomes 6 months postoperatively. The accuracy of the maxilla centroid position was improved in mandible-first sequencing surgery: mandible-first 1.87±0.94 mm versus maxilla-first 2.70±0.75 mm (P<0.05). Moreover, no significant difference was detected in the translational and orientational discrepancies between the 2 groups. Neither sequencing procedure differed in the overall stability: maxilla-first (1.48±1.13 mm) versus mandible-first (1.57±0.90 mm). This study indicated that the mandible-first surgery leads to a more accurate maxilla position than the maxilla-first surgery for patients with skeletal class II malocclusion concomitant with the unstable condyle-fossa relation.

Predictability of the virtual surgical plan for orthognathic surgery with the mandible surgery first sequence

The aim of this study was to compare the virtually planned position to the postoperative position of the maxilla, having performed the maxilla-first sequence or mandible-first sequence orthognathic surgery. An audit of 64 patients who underwent bimaxillary surgery between 2017 and 2020 was performed. Thirty patients had maxilla-first surgery and 34 had mandible-first surgery. The planned and post-surgical positions were analyzed using specific skeletal landmarks. Differences were calculated and the two-sample t-test was used to compare the groups. Measured differences between the planned and postoperative results differed significantly between the mandible-first and maxillary-first surgery groups (P < 0.001). The maxillary central incisors were under-advanced in the anterior-posterior direction in both groups. Most data points showed deviation from the surgical plan ≤ 2 mm and ≤ 4°. Secondarily, maxillary under-advancement in the mandible-first cohort was evaluated; these patients were subdivided into rigid and non-rigid fixation groups. The non-rigid fixation group showed less accuracy compared to the rigid fixation group, which was statistically significant (P = 0.014). The findings of this study demonstrate that virtual surgical planning can be less accurate in predicting the maxillary incisor position when performing mandible-first surgery, but this inaccuracy is within the acceptable range and can be mitigated by rigid fixation of the mandible.

Surgical accuracy of CAD/CAM splints using virtual surgical planning in orthognathic surgery: policy implications for healthcare in Australia

BACKGROUND

This study examines post-surgical outcomes of maxillary position using virtual surgical planning (VSP) with computer designed and manufactured surgical splints, without the use of costly patient specific implants (PSI), in the treatment of routine nonsyndromic orthognathic patients. The cost of these personalized medical devices and their impact in the setting of cranio-maxillofacial surgery is currently under review by The Department of Health and Aged Care in Australia.

METHODS

This is a single-centre retrospective analysis of 49 patients who underwent bimaxillary orthognathic surgery by a single surgeon at Epworth Richmond Hospital (Victoria, Australia) over a period spanning 2016 to 2020. Patients were included in the study provided their surgery was facilitated using VSP with manufacture of computer designed occlusal splints.

RESULTS

Use of computer designed and manufactured splints were highly reliable in reproducing the virtual surgical plan, when using palatal plane, upper incisor angulation, and anterior upper facial height.

CONCLUSION

Use of computer designed and manufactured splints provide a method of leveraging the accuracy of VSP methods, without the additional costs associated with PSI. These findings may assist in appropriate resource allocation and case stratification in patients undergoing orthognathic surgery.

Sequencing in Orthognathic Bimaxillary Surgery: Which Jaw Should Be Operated First? A Scoping Review

Bimaxillary orthognathic surgery is widely used for the correction of dentoskeletal deformities. Surgery sequencing (maxilla or mandible first) remains debated, and guidelines and consensus are lacking. This scoping review summarizes the state of the art and compares the advantages and disadvantages of both approaches. The review was conducted following PRISMA-ScR guidelines. Three electronic databases (PubMed, Scopus, Web of Science) were searched using the PICO protocol and key words in orthognathic surgical sequencing. Four reviewers screened the records independently, and disagreement was resolved by consensus. A total of 23 records met the inclusion criteria. The advantages and disadvantages of the two approaches were compared and assessed for accuracy of reporting. Within the limitations of the present study, available evidence for the intrinsic advantages and the accuracy of the mandible-first sequence supports the choice of this approach in most cases. Nevertheless, each clinical case needs to be evaluated individually, as no dogmatic recommendations can be given for sequencing in bimaxillary orthognathic surgery.

Computer Guided Generated Dual-Purpose Splint for Bilateral Sagittal Split Osteotomy

Purpose

to evaluate the efficacy of dual-purpose computer-generated splint in guiding the proximal and the distal segment in bilateral sagittal split osteotomy.

Patients and Method

It was a prospective case series study directed on 8 class III patients indicating the need of maxillary advancement and mandibular set back by bilateral sagittal split osteotomy. A CAD/CAM splint is generated to guide the distal segment to the stable maxilla and at the same time a grooved extension to engage the proximal segment ensuring the condyle in its planned position during fixation. The primary outcome was measured by calculating the difference between the pre- and post-operative condylar segment position.

Results

The present study included five female patient and three male patient with mean age of 28.4 ± 5.1 years. The accuracy of the splint in positioning the mandibular proximal segment showed promising results ranging from 2.59 to 0.49.

Conclusion

The dual-purpose splint introduced in this study showed satisfied results in maintaining the pre-operative condylar position while securing the distal segment in the desired plan.

Current trends in orthognathic surgery

Orthognathic surgery has steadily evolved, gradually expanding its scope of application beyond its original purpose of simply correcting malocclusion and the facial profile. For instance, it is now used to treat obstructive sleep apnea and to achieve purely cosmetic outcomes. Recent developments in three-dimensional digital technology are being utilized throughout the entire process of orthognathic surgery, from establishing a surgical plan to printing the surgical splint. These processes have made it possible to perform more sophisticated surgery. The goal of this review article is to introduce current trends in the field of orthognathic surgery and controversies that are under active discussion. The role of a plastic surgeon is not limited to performing orthognathic surgery itself, but also encompasses deep involvement throughout the entire process, including the set-up of surgical occlusion and overall surgical planning. The authors summarize various aspects in the field of orthognathic surgery with the hope of providing helpful information both for plastic surgeons and orthodontists who are interested in orthognathic surgery.

Algorithm to the treatment of Crouzon syndrome

Clinical reports regarding the entire surgical sequence in Crouzon syndrome from the neonatal period to the adult age are rare. The purpose of this study is to trace an operative algorithm with a long term follow up in a homogenous group of patients affected by Crouzon syndrome. A retrospective review was conducted for all patients affected by Crouzon syndrome who completed the entire surgical sequence. 7 Crouzon patients (4 females, 3 males) completed the entire surgical sequence at different ages: fronto-orbital advancement (0.9 years), LF III distraction osteogenesis (11.5 years) and orthognathic surgery (18 years). The mean age at the last follow up was 19.3 years; normalization of the face was obtained in all cases with improvement of the respiratory problems. After orthognathic surgery, all patients had stable occlusion. A one-year postoperative CBCT scan revealed almost complete ossification of all osteotomy sites. Frontoorbital advancement and modified Le Fort III distraction osteogenesis are reliable surgical procedures. SARME and conventional orthognathic surgery with reductive genioplasty and fat grafting are performed at the end of the surgical sequence to enhance facial aesthetics.

PSI-Guided Mandible-First Orthognathic Surgery: Maxillo-Mandibular Position Accuracy and Vertical Dimension Adjustability

In orthognathic surgery, patient-specific osteosynthesis implants (PSIs) represent a novel approach for the reproduction of the virtual surgical planning on the patient. The aim of this study is to analyse the quality of maxillo-mandibular positioning using a hybrid mandible-first mandibular-PSI-guided procedure on twenty-two patients while the upper maxilla was fixed using manually bent stock titanium miniplates. The virtual surgical plan was used to design PSIs and positioning guides, which were then 3D printed using biocompatible materials. A Cone Beam Computed Tomography (CBCT) scan was performed one month after surgery and postoperative facial skeletal models were segmented for comparison against the surgical plan. A three-dimensional cephalometric analysis was carried out on both planned and obtained anatomies. A Spearman correlation matrix was computed on the calculated discrepancies in order to achieve a more comprehensive description of maxillo-mandibular displacement. Intraoperatively, all PSIs were successfully applied. The procedure was found to be accurate in planned maxillo-mandibular positioning reproduction, while maintaining a degree of flexibility to allow for aesthetics-based verticality correction in a pitch range between −5.31 and +1.79 mm. Such a correction did not significantly affect the achievement of planned frontal symmetry.

Orthognathic Surgery of the Mandible

Orthognathic surgery performed in conjunction with orthodontic treatment is commonly performed to correct skeletal irregularities and realign the maxillomandibular relationship to improve occlusal function and facial esthetics. A thorough understanding of soft tissue esthetics, skeletal and occlusal relationships, and surgical techniques is required to obtain successful results. Surgical techniques have evolved greatly throughout history, as technological advances such as virtual surgical planning have become available and widely used to obtain predictable movements with minimized complications. The aim of this article is to review the orthognathic surgical procedures of the mandible, with particular attention to the indications, contraindications, preoperative assessment, surgical technique, and possible complications encountered.

Orthognathic Surgery-LeFort I Osteotomy

Orthognathic surgery is a complex type of facial surgery that can have a profound impact on a patient's occlusal function and facial aesthetics. Close collaboration between the maxillofacial surgeon and an orthodontist is required, and the surgical team must have a strong foundation in facial analysis and firm understanding of the maxillofacial skeleton to achieve surgical success. Herein, we review the maxillary LeFort I osteotomy as it pertains to orthognathic surgery, with particular attention to the indications, contraindications, preoperative assessment, surgical technique, and possible complications encountered.

Comparison of actual amount of movement with surgical treatment objective in the orthognathic maxillary repositioning

OBJECTIVE

To compare the postoperative position of the maxilla with the surgical treatment objectives (STO) in bimaxillary orthognathic surgery for evaluating the surgical accuracy and investigating the pattern and cause of the discrepancy.

METHODS

Patients undergoing conventional bimaxillary orthognathic surgery by a single oral and maxillofacial surgeon were enrolled. Utilizing the superimposition of preoperative and postoperative computed tomography images, the actual amounts of positional change of both the maxillary central incisor and first molars were compared with those of STO. All the patients were divided into two groups according to the actual discrepancy between STO and the postoperative position and factors that may affect surgical accuracy were analyzed.

RESULTS

In 62 cases, the absolute mean value of the positional difference between STO and the actual outcome was 2.20 mm (X-axis, 0.93 mm; Y-axis, 1.31 mm; and Z-axis, 1.09 mm) in the maxillary central incisor. The signed mean value of the central incisor was -0.07 mm, 0.79 mm, and -0.57 mm in the X-, Y-, and Z-axes, respectively, and the value in the Y- and Z-axes showed a statistically significant difference in comparison with STO (P<0.01). Age, sex, skeletal Angle classification, maxillary and mandibular profile, use of 3D virtual surgery, facial asymmetry, and yawing correction did not show a statistically significant correlation with surgical accuracy at the central incisor.

CONCLUSION

There was an acceptable range of discrepancy between postoperative maxillary position and STO after orthognathic surgery; however, there was a tendency for posterior and downward movement in the maxillary anterior teeth.

Current Trends in Orthognathic Surgery in Poland—A Retrospective Analysis of 124 Cases

The analysis aims at assessing the current trends in orthognathic surgery. The retrospective study covered a group of 124 patients with skeletal malocclusion treated by one team of maxillofacial surgeons at the University Hospital in Zielona Góra, Poland. Various variables were analysed, including demographic characteristics of the group, type of deformity, type of osteotomy used, order in which osteotomy was performed and duration of types of surgery. The mean age of the patients was 28 (ranging from 17 to 48, SD = 7). The group included a slightly bigger number of females (59.7%), with the dominant skeletal Class III (64.5%), and asymmetries were found in 21.8% of cases. Types of osteotomy performed during surgeries were divided as follows: LeFort I, segmental LeFort I, BSSO, BSSO with genioplasty, LeFort I with BSSO, LeFort I with BSSO and genioplasty, segmental LeFort I with BSSO, isolated genioplasty. Bimaxillary surgeries with and without genioplasty constituted the largest group of orthognathic surgeries (49.1%), and a slightly smaller percentage were one jaw surgeries (46.7%). A statistically significant correlation was found between the type of surgery and the skeletal class. In patients with skeletal Class III, bimaxillary surgeries were performed significantly more often than in patients with skeletal Class II (57.5% vs. 20.0%; p = 0.0002). The most common type of osteotomy in all surgeries was bilateral osteotomy of the mandible modo Obwegeser–Epker in combination with Le Fort I maxillary osteotomy (42.7%). The order of osteotomies in bimaxillary surgeries was mandible first in 61.3% of cases. The longest surgery was bimaxillary osteotomy with genioplasty (mean = 265 min), and the shortest surgery was isolated genioplasty (mean = 96 min). The results of the analysis show a significant differentiation between the needs of orthognathic surgery and the types of corrective osteotomy applied to the facial skeleton.

Relapse and temporomandibular joint dysfunction (TMD) as postoperative complication in skeletal class III patients undergoing bimaxillary orthognathic surgery: A systematic review

Objectives

The aim of this study was to determine Relapse and TMD as postoperative complication in skeletal class III patients undergoing bimaxillary orthognathic surgery.

Materials and methods

Data was obtained by database searching using The Cochrane Central Register of Controlled Trials (central), PUBMED, SCOPUS, EMBASE, Google scholar, National Medical library, New Delhi. The titles and abstracts of the electronic search results were screened and evaluated by two observers for eligibility according to the inclusion and exclusion criteria.

Results

5261 articles were retrieved for the review. Among these, 3474 duplicate articles were removed. 418 studies were selected based on the eligibility criteria. For the present review, 30 articles were included after elimination according to the inclusion criteria. The Prisma diagram flowchart demonstrates our selection scheme. Quality assessment criteria to evaluate the studies were decided by two review authors in accordance with CONSORT guidelines. Each study was assessed using the evaluation method described in the Cochrane Handbook for Systematic Reviews. Among the 30 studies included in the review, marked degree of relapse in the mandible was noted from 3 months - 1 year postoperatively in 8 studies, 5 studies reported both TMD prevalence and relapse, whereas only 4 studies reported TMD disorder alone.

Conclusion

Complications of relapse and TMD are associated with bimaxillary orthognathic surgery procedures. More RCTs and CCTs are needed in this regard to get better quality evidence. This review was registered with PROSPERO: CRD42020211342.

Bilateral mandibular block improves pain relief and morphine consumption in mandibular osteotomies: a prospective, randomized, double-blind, placebo-controlled clinical trial

BACKGROUND

The sensory innervation of the lower jaw mainly depends on the third root of the trigeminal nerve, the mandibular nerve (V3). The aim of this single-center, prospective, randomized, double-blind, placebo-controlled study was to evaluate the effectiveness of bilateral V3 block for postoperative analgesia management in mandibular osteotomies.

METHODS

107 patients undergoing mandibular surgery (75 scheduled osteotomies and 32 mandible fractures) were randomized in two groups. A bilateral V3 block was performed in each group, either with ropivacaine 0.75% (block group, n=50) or with a placebo (placebo group, n=57). A postoperative multimodal analgesia was equally provided to both groups. The primary outcome was the cumulative morphine consumption at 24 hours. Secondary outcomes were the occurrence of severe pain and the incidence of postoperative nausea and vomiting (PONV) in the first 24 hours. Data were analyzed on an intention-to-treat basis.

RESULTS

The cumulative morphine consumption at 24 hours was significantly lower in the block group (median 8.0 mg (IQR 2.0-21.3) vs 12.0 mg (IQR 8.0-22.0), p=0.03), as well as the incidence of severe pain during the 24 hours of follow-up (4.0% vs 22.8%, p<0.01). The mandibular block had no impact on the incidence of PONV.

CONCLUSION

Bilateral V3 block for mandibular osteotomies is an effective opioid-sparing procedure. It provided better postoperative analgesia in the first 24 hours, and it did not affect PONV incidence.

TRIAL REGISTRATION NUMBER

NCT02618993.

Recent advances in orthognathic surgery

PURPOSE OF REVIEW

The aim of this article is to review the recent literature on orthognathic surgery for treatment of malocclusion and obstructive sleep apnea (OSA). The discussion outlines the refinements of the procedure and advances in technology.

RECENT FINDINGS

Maxillomandibular advancement (MMA) may be performed for complex malocclusion and OSA. Although orthodontic management followed by MMA has been the gold standard in managing complex cases, the surgery first approach for treatment of malocclusion has increased in popularity because of decreased treatment time and improved patient quality of life. MMA continues to be the gold-standard for treatment of refractory sleep apnea. Technological advancements, including 3D printing and virtual surgical planning, have enhanced the patient experience and provided more efficiency to this surgery.

SUMMARY

First introduced in the 19th century, orthognathic surgery has continuously been refined. Over the last few decades, there has been increasing support for a surgery first approach in the treatment of malocclusion. MMA has revolutionized the surgical treatment of OSA and provides the best opportunity for success or cure in patients with complex obstructive patterns. Technology has enhanced the surgical process and created more efficiency for the surgeon and patient. VIDEO ABSTRACT: http://links.lww.com/COOH/A40.

Mandibular micrognathia and vertical maxillary excess correction with combination LeFort I and inverted L osteotomies

A 34-year-old woman with mandibular micrognathia, vertical maxillary excess, and an open bite characterized by a "bird-face" deformity was treated with orthodontics combined with LeFort I and bilateral inverted L osteotomies. The total treatment time was 16 months. Her occlusion and facial appearance were significantly improved by a surgical-orthodontic plan. This case report presents the discussion of a unique and complex orthognathic surgical case and the myriad of orthodontic and surgical considerations that it involved.

Accuracy of 3D virtual surgical planning for maxillary positioning and orientation in orthognathic surgery

OBJECTIVE

This retrospective and observational study evaluated the accuracy of a 3D virtual surgical planning (VSP) for the maxillary positioning and orientation in patients undergoing bimaxillary orthognathic surgery, comparing the planned and postoperative outcomes.

SETTING AND SAMPLE POPULATION

Seventy consecutive patients of both sexes, who were submitted to bimaxillary orthognathic surgery between 2015 and 2019 were included in our study.

MATERIAL AND METHODS

The patients were evaluated by fusing preoperative planning and postoperative outcome using cone-beam computed tomography scan evaluation. Three-dimensional VSP and postoperative outcomes were compared by using three linear and three angular measurements. The main outcome interest was the difference between the VSP movement, and the surgical movement obtained. The success criterion adopted was a mean linear difference of <2 mm and a mean angular difference of <4°.

RESULTS

Results were analysed using a linear mixed model with fixed and random effects, at α = .05. No significant statistical differences were found for linear and angular measurements between the planned and postsurgical outcomes (P > .05). All overlapping points presented values within the range considered clinically irrelevant (<2 mm; <1°).

CONCLUSIONS

Three-dimensional VSP was executed with a high degree of accuracy. When comparing the planned and postsurgical outcomes, all overlapping points presented values within the range considered clinically irrelevant.

Does Mandible-First Sequencing Increase Maxillary Surgical Accuracy in Bimaxillary Procedures?

PURPOSE

In bimaxillary procedures, it is important to know how the chosen sequence affects the surgical outcome. The purpose of this study was to explore whether the theoretical advantages of using the mandible-first procedure were supported by clinical data.

MATERIALS AND METHODS

The authors performed a retrospective investigation on a cohort compiled from 3 published retrospective studies. The sample was composed of patients treated at the Radboud University Nijmegen Medical Centre (Nijmegen, the Netherlands) from 2010 to 2014 and the Odense University Hospital (Odense, Denmark) from 2011 to 2015. The inclusion criterion was bimaxillary surgery without maxillary segmentation. The exclusion criterion was lack of a virtual surgical plan. The primary outcome variable was surgical accuracy, defined as the mean difference between the obtained outcome and the virtual surgical plan. The primary predictor variable was the comparison between mandible-first and maxilla-first sequencing. Secondary predictors were inferior maxillary repositioning and counterclockwise (CCW) rotation. The confounding variable was the virtually planned reposition. Results were analyzed by mixed-model regression encompassing all variables, followed by a detailed analysis of positive results using 2-sample t tests.

RESULTS

Overall, 145 patients were included for analysis (98 women; mean age, 28 years). Operating on the mandible first notably influenced maxillary positioning and placed the maxilla 1.5 mm posterior and with 1.4° of CCW rotation compared with virtual surgical planning. The interaction of surgical sequence with maxillary rotation showed similar surgical accuracy between maxilla-first surgery with clockwise rotation and mandible-first surgery with CCW rotation. Inferior maxillary repositioning resulted in the maxilla being placed 1.7 mm (maxilla-first sequence) and 2.0 mm (mandible-first sequence) posterior to the planned position.

CONCLUSION

Surgical accuracy was considerably influenced by sequencing in bimaxillary procedures. It remains important to know how the chosen sequence affects the surgical outcome so that the virtual surgical plan can be adjusted accordingly.

Long-term effects of Class II Herbst treatment on the pharyngeal airway width

Objective

The aim was to assess the long-term effects of Class II malocclusion treatment with the Herbst appliance on the pharyngeal airway (PA) width in comparison to untreated individuals with Classes I and II malocclusion.

Methods

Lateral cephalometric radiographs of 13 male Class II patients from before (T1) and after (T2) treatment with the Herbst appliance as well as after the end of growth (T3) were retrospectively analyzed and compared to two untreated age- and gender-matched samples with Class I (n = 13) or Class II (n = 13) malocclusion. The PA dimensions were measured using the parameters p (narrowest distance between the soft palate and the posterior pharyngeal wall) and t (narrowest distance between the base of the tongue and the posterior pharyngeal wall). In addition, standard cephalometric measurements were performed.

Results

Relevant changes in PA dimensions were only seen for the post-treatment period, during which the distances p and t showed a significant increase in the Herbst group only (∆p: 2.3 mm, ∆t: 3.3 mm) while remaining similar in both untreated groups (∆p: 0.5 mm, ∆t: 0.5 mm, respectively, ∆p: 0.7 mm, ∆t: 1.6 mm). During the same period, posterior face height showed a significantly larger increase in the Herbst group than in both control groups (8.2 versus 5.8 mm, respectively, 5.4 mm), whereas anterior face height (NL-Me) showed a similar development in all groups (4.6 versus 4.4 mm, respectively 3.2 mm).

Conclusion

In the long term, Herbst treatment resulted in a significant post-treatment increase of PA width, possibly due to an increased lower posterior facial height development compared to untreated individuals.

Alteration of Occlusal Plane in Orthognathic Surgery: Clinical Features to Help Treatment Planning on Class III Patients

Dentofacial deformities (DFD) presenting mainly as Class III malocclusions that require orthognathic surgery as a part of definitive treatment. Class III patients can have obvious signs such as increasing the chin projection and chin throat length, nasolabial folds, reverse overjet, and lack of upper lip support. However, Class III patients can present different facial patterns depending on the angulation of occlusal plane (OP), and only bite correction does not always lead to the improvement of the facial esthetic. We described two Class III patients with different clinical features and inclination of OP and had undergone different treatment planning based on 6 clinical features: (I) facial type; (II) upper incisor display at rest; (III) dental and gingival display on smile; (IV) soft tissue support; (V) chin projection; and (VI) lower lip projection. These patients were submitted to orthognathic surgery with different treatment plannings: a clockwise rotation and counterclockwise rotation of OP according to their facial features. The clinical features and OP inclination helped to define treatment planning by clockwise and counterclockwise rotations of the maxillomandibular complex, and two patients undergone to bimaxillary orthognathic surgery showed harmonic outcomes and stables after 2 years of follow-up.

Effects of mandibular setback with or without maxillary advancement osteotomies on pharyngeal airways: An overview of systematic reviews

Background

Mandibular setback osteotomies potentially lead to narrowing of the pharyngeal airways, subsequently resulting in post-surgical obstructive sleep apnea (OSA).

Objective

To summarize current evidence from systematic reviews that has evaluated pharyngeal airway changes after mandibular setback with or without concomitant upper jaw osteotomies.

Methodology

PubMed, EMBASE, Web of Science, and Cochrane Library databases were searched with no restriction of language or date. Systematic reviews studying changes in pharyngeal airway dimensions and respiratory parameters after mandibular setback with or without concomitant upper jaw osteotomies have been identified, screened for eligibility, included and analyzed in this study.

Results

Six systematic reviews have been included. While isolated mandibular setback osteotomies result in reduced oropharyngeal airway dimensions, the reduction is lesser in cases with concomitant upper jaw osteotomies. Only scarce evidence exists currently to what happens to naso- and hypo-pharyngeal airways. There is no evidence for post-surgical OSA, even though some studies reported reduced respiratory parameters after single-jaw mandibular setback with or without concomitant upper jaw osteotomies.

Conclusion

Although mandibular setback osteotomies reduce pharyngeal airway dimensions, evidence confirming post-surgical OSA was not found. Nevertheless, potential post-surgical OSA should be taken into serious consideration during the treatment planning of particular orthognathic cases. As moderate evidence exists that double-jaw surgeries lead to less compromised post-surgical pharyngeal airways, they should be considered as the method of choice especially in cases with severe dentoskeletal Class III deformity.

Study registration

PROSPERO (registration number: CRD42016046484).

Achievability of 3D planned bimaxillary osteotomies: maxilla-first versus mandible-first surgery

The present study was aimed to investigate the effects of sequencing a two-component surgical procedure for correcting malpositioned jaws (bimaxillary osteotomies); specifically, surgical repositioning of the upper jaw-maxilla, and the lower jaw-mandible. Within a population of 116 patients requiring bimaxillary osteotomies, the investigators analyzed whether there were statistically significant differences in postoperative outcome as measured by concordance with a preoperative digital 3D virtual treatment plan. In one group of subjects (n = 58), the maxillary surgical procedure preceded the mandibular surgery. In the second group (n = 58), the mandibular procedure preceded the maxillary surgical procedure. A semi-automated analysis tool (OrthoGnathicAnalyser) was applied to assess the concordance of the postoperative maxillary and mandibular position with the cone beam CT-based 3D virtual treatment planning in an effort to minimize observer variability. The results demonstrated that in most instances, the maxilla-first surgical approach yielded closer concordance with the 3D virtual treatment plan than a mandibular-first procedure. In selected circumstances, such as a planned counterclockwise rotation of both jaws, the mandible-first sequence resulted in more predictable displacements of the jaws.

How Many Oral and Maxillofacial Surgeons Does It Take to Perform Virtual Orthognathic Surgical Planning?

PURPOSE

Virtual surgical planning (VSP) has become routine practice in orthognathic treatment planning; however, most surgeons do not perform the planning without technical assistance, nor do they routinely evaluate the accuracy of the postoperative outcomes. The purpose of the present study was to propose a reproducible method that would allow surgeons to have an improved understanding of VSP orthognathic planning and to compare the planned surgical movements with the results obtained.

MATERIALS AND METHODS

A retrospective cohort of bimaxillary orthognathic surgery cases was used to evaluate the variability between the predicted and obtained movements using craniofacial landmarks and McNamara 3-dimensional cephalometric analysis from computed tomography scans. The demographic data (age, gender, and skeletal deformity type) were gathered from the medical records. The data analysis included the level of variability from the predicted to obtained surgical movements as assessed by the mean and standard deviation. For the overall sample, statistical analysis was performed using the 1-sample t test. The statistical analysis between the Class II and III patient groups used an unpaired t test.

RESULTS

The study sample consisted of 50 patients who had undergone bimaxillary orthognathic surgery. The overall evaluation of the mean values revealed a discrepancy between the predicted and obtained values of less than 2.0 ± 2.0 mm for all maxillary landmarks, although some mandibular landmarks were greater than this value. An evaluation of the influence of gender and deformity type on the accuracy of surgical movements did not demonstrate statistical significance for most landmarks (P > .05).

CONCLUSIONS

The method provides a reproducible tool for surgeons who use orthognathic VSP to perform routine evaluation of the postoperative outcomes, permitting the identification of specific variables that could assist in improving the accuracy of surgical planning and execution.