Chang Gung Forum: An Exemplary Strategy for Implementing a Multidisciplinary Network of Experts in Craniofacial Anomalies.

INTRODUCTION: The Chang Gung Forum has been dedicated to the care of craniofacial anomalies since 2000. This annual continuing medical education program focuses on orofacial cleft and surgery-first orthognathic surgery by providing up-to-date information and management guidelines. This study explored how the Chang Gung Forum has influenced medical perspectives, decisions, and practices in a multidisciplinary craniofacial team. METHODS: Between 2000 and 2022, 20 Chang Gung Forums have been held. A questionnaire was distributed among 170 attendees who had participated in the forum more than once. The questionnaire collected information on the participants' experiences and levels of satisfaction with the educational program and whether or how it had influenced their clinical practice. RESULTS: Valid responses from 86 attendees (response rate, 50.6%) who had participated more than once were collected and analyzed. The overall satisfaction rate of the Chang Gung Forum based on the respondents' most recent visits was 4.28 ± 0.63 out of 5. Of the respondents, 90.9% acknowledged changes in their clinical practice, with modifications in surgery plans and decisions being the most notable (48.5%). In addition, comprehension increased throughout years of attending the annual forum (P < 0.001). CONCLUSION: The Chang Gung Forum has contributed markedly to the community of congenital craniofacial anomalies. The program will continue providing updated information and influencing the clinical decision-making of health care professionals.

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.

Site and severity of facial asymmetry after bimaxillary surgery for class III deformity: a case-control study.

OBJECTIVES: The study aimed (1) to evaluate the site and severity of facial asymmetry in Class III patients before and after bimaxillary surgery, and (2) to identify the influence of initial severity and positional jaw asymmetry on residual facial asymmetry. MATERIALS AND METHODS: Preoperative and postoperative cone-beam computed tomography of 65 patients with Class III facial asymmetry who underwent bimaxillary surgery were evaluated. Five midline and 14 paramedian facial soft tissue landmarks were identified to assess facial asymmetry. The outcomes were compared to a control group consisting of 30 age- and gender-matched Class I subjects. The postoperative positional jaw asymmetry (i.e., shift, roll, yaw) of each osteotomy segment (maxilla, mandible, chin, ramus) was also measured. RESULTS: Before surgery, the asymmetry was more severe at the chin, middle and lower contour. Bimaxillary surgery effectively corrected facial asymmetry, particularly in achieving normalization of chin deviation. However, significant asymmetry persisted postoperatively in the middle and lower contour (p < 0.001 and p < 0.01, respectively), which was affected by the positional ramus asymmetry in the roll and shift. CONCLUSIONS: Deviation of the chin, middle and lower contour contributed significantly to overall facial asymmetry in Class III asymmetry. Despite normalization of the chin deviation after bimaxillary surgery, asymmetry persisted at the middle and lower contour, primarily as the result of insufficient correction of the positional ramus asymmetry. CLINICAL RELEVANCE: Understanding the residual asymmetry after bimaxillary surgery is important for minimizing deviation and optimizing the surgical planning for its correction.

Extensive Gingivoperiosteoplasty Versus Secondary Alveolar Bone Grafting in Patients With Complete Bilateral Cleft Lip and Palate During the Mixed Dentition Period: A Retrospective Outcome Analysis.

BACKGROUND: The concept of gingivoperiosteoplasty (GPP) in the mixed dentition stage as compared with secondary alveolar bone grafting (ABG) in management of alveolar cleft has not been much discussed upon. The authors present the experience with extensive GPP and ABG in the mixed dentition stage in complete bilateral alveolar cleft cases. METHODS: A retrospective review of nonsyndromic patients with complete bilateral alveolar cleft operated on with either GPP or ABG (iliac crest) in the mixed dentition stage with at least 1-year follow-up was performed. Dental occlusal radiographs were evaluated for level of bone gain using Bergland and Witherow scales. Statistical evaluation of clinical success and procedure-related complications was conducted using χ2 test and odds ratio. RESULTS: Twenty-four patients in the GPP group and 20 in the ABG group were comparatively studied. Clinical success rate as indicated by Bergland scales I and II (87.5% in GPP vs 82.5% in ABG; P = 0.731), complication rate (20.83% in GPP vs 30% in ABG; P = 0.484), and status of canine eruption showed no significant differences in clinical outcomes in both groups. CONCLUSIONS: The technique of extensive GPP as described by authors shows equal efficacy to secondary ABG for management of bilateral alveolar clefts during the mixed dentition period.

Skeletal stability after bimaxillary surgery with surgery-first approach for class III asymmetry is not related to virtual surgical occlusal contact.

OBJECTIVES: Surgery-first orthognathic surgery is rarely used in class III asymmetry due to concerns of reduced skeletal stability from unstable surgical occlusion. This study aimed to evaluate if skeletal stability after surgery-first orthognathic surgery is related to virtual surgical occlusal contact or surgical change. MATERIALS AND METHODS: We studied 58 adults with class III asymmetry, consecutively corrected by Le Fort I osteotomy and bilateral sagittal split osteotomy using a surgery-first approach. Dental casts were manually set to measure virtual surgical occlusal contact including contact distribution, contact number, and contact area. Cone-beam computed tomography taken before treatment, 1-week post-surgery, and after treatment was used to measure surgical change and post-surgical stability of the maxilla and mandible in translation (left/right, posterior/anterior, superior/inferior) and rotation (pitch, roll, yaw). The relationship between skeletal stability and surgical occlusal contact or surgical change was evaluated with correlation analysis. RESULTS: Significant instability was found in the mandible but not in the maxilla. No correlation was found between the maxillary or mandibular stability and surgical occlusal contact (all p > 0.01). However, a significant correlation was found between the maxillary (roll and yaw) or mandibular (shift, roll and pitch) stability and its surgical change (all p < 0.001). CONCLUSIONS: In correction of class III asymmetry with surgery-first bimaxillary surgery, the skeletal stability is not related to the virtual surgical occlusal contact, but surgical skeletal change. CLINICAL RELEVANCE: Planned over-correction is a reasonable option for correction of severe shift or roll mandibular asymmetry in bimaxillary surgery for class III deformity.

Type of mandibular asymmetry affects changes and outcomes of bimaxillary surgery for class III asymmetry.

OBJECTIVES: Various methods have been used to classify class III asymmetry. There is little information on the use of an asymmetry index to examine soft tissue changes and outcomes for patients with class III asymmetry. This study aimed to (1) evaluate soft tissue changes and outcomes for three types of mandibular asymmetry and (2) determine if measures are associated with type of asymmetry. MATERIALS AND METHODS: Adults who consecutively underwent bimaxillary surgery using surgery-first approach for correction of class III asymmetry were divided into three groups based on type of mandibular asymmetry. This previously reported classification system is simple and mutually independent, categorizing mandibular asymmetry according to the amount and direction of ramus asymmetry relative to menton deviation: patients with a larger transverse ramus distance on the menton deviation side were divided into group 1 and group 2; group 1 (n = 45) exhibited a menton deviation larger than ramus discrepancy; group 2 (n = 11) exhibited a menton deviation less than ramus discrepancy; group 3 (n = 22) had larger transverse ramus distance contralateral to the side of the menton deviation. Soft tissue facial asymmetry indices, calculated from cone beam computed tomography images, assessed midline and contour asymmetry presurgery, changes postsurgery, and outcomes. RESULTS: Compared with groups 1 and 2, the presurgery index for contour and midline asymmetry was smallest for group 3. All the three groups had significant improvement in midline asymmetry postsurgery, and outcome measures were good; there were no differences between groups. However, contour asymmetry only improved significantly for groups 1 and 2. The outcome for contour asymmetry was fair for groups 1 and 3 and poor for group 2. CONCLUSIONS: Bimaxillary surgery significantly improved facial midline asymmetry. The type of mandibular asymmetry was associated with postsurgical changes and outcomes for contour asymmetry. CLINICAL RELEVANCE: Understanding the types of mandibular asymmetry could help clinicians to develop treatment plans and predict treatment changes and outcomes.

Skeletal and upper airway stability following modified maxillomandibular advancement for treatment of obstructive sleep apnea in skeletal class I or II deformity.

OBJECTIVES: Maxillomandibular advancement (MMA) is an effective short-term treatment for obstructive sleep apnea (OSA). This study aimed to evaluate the long-term stability of the facial skeleton, upper airway, and its surrounding structures, as well as improvement in OSA following MMA. MATERIALS AND METHODS: Thirty-one adults with moderate-to-severe OSA underwent surgery-first modified MMA as primary surgery. Polysomnography and cone-beam computed tomography were obtained pre-surgery, early post-surgery, and at follow-up (i.e., ≥ 2 years post-surgery). Image analysis software assessed the facial skeleton, upper airway, and its surrounding structures. RESULTS: Early post-surgery, apnea-hypopnea index (AHI) had decreased significantly (p < 0.001) and the minimum oxygen saturation (MSAT) increased (p = 0.001), indicating significant improvement in OSA. At follow-up, the AHI and MSAT remained stable. However, the anterior maxilla, soft palate, and tongue moved backward while the hyoid moved downward. There was also a significant decrease in the minimal cross-sectional area of the oropharynx. The reduction in AHI was significantly related to the anterior movement of the anterior maxilla and tongue, inferior movement of the posterior maxilla, and superior movement of the soft palate tip. CONCLUSIONS: The improvement of OSA after modified MMA remained stable for at least 2 years following treatment, despite the relapse of the facial skeleton, upper airway, and its surrounding structures. The reduction of AHI was not related to changes in the caliber of the upper airway but to the movement of the maxilla, soft palate, and tongue. Clinical relevance Modified MMA is clinically effective for long-term treatment of patients with moderate-to-severe OSA.

Comparison of stability and outcomes of surgery-first bimaxillary surgery for skeletal class III deformity between unilateral and bilateral cleft lip and palate.

OBJECTIVES: Some adults with cleft lip and palate (CLP) require orthognathic surgery due to skeletal deformity. This prospective study aimed to (1) compare skeletal stability following bimaxillary surgery for correction of class III deformity between patients with unilateral CLP (UCLP) and bilateral CLP (BCLP), and (2) identify risk factors of stability. MATERIALS AND METHODS: Adults with CLP and skeletal class III deformities who underwent surgery-first bimaxillary surgery were divided into two groups according to cleft type: UCLP (n = 30) and BCLP (n = 30). Skeletal stability was assessed with measures from cone beam computed tomography images of the maxilla and mandible taken before treatment, 1-week and ≥ 1 year postsurgery for translation (left/right, posterior/anterior, superior/inferior) and rotation (yaw, roll, pitch); multiple regression analysis examined risk factors. RESULTS: At follow-up, the maxilla moved upwards in both groups, and backwards in the UCLP group. The mandible moved forward and upward, shifted to the cleft (deviated) side, and rotated upward in both groups. The amount of surgical advancement was a risk factor for sagittal stability in the maxilla (ß = -0.14, p < 0.05). The mandible had three risk factors for sagittal stability: age (ß = -0.23, p < 0.05), surgical team (ß = -1.83, p < 0.05), and amount of surgical setback (ß = -0.32, p = 0.001). CONCLUSIONS: Two years after bimaxillary surgery, patients with UCLP had a higher sagittal relapse of the maxilla compared with patients with BCLP, which was due to a greater surgical advancement in the patients with UCLP. CLINICAL RELEVANCE: Surgery-first bimaxillary surgery results in favorable treatment outcomes for correction of cleft-related class III deformity. Severity of jaw discrepancy and surgeons should be considered in the surgical design of overcorrection.

What are the Effects of Age and Presence of Third Molars on the Occurrence of Unfavorable Splits During Sagittal Split Osteotomy?

PURPOSE: Several studies have investigated risk factors of unfavorable splits associated with sagittal split osteotomies but yielded conflicting information. The purpose of this study is to estimate the frequency of and identify factors associated with unfavorable splits during sagittal split osteotomies (SSOs). MATERIAL AND METHODS: A retrospective cohort study was conducted on patients who underwent orthognathic surgery, including SSOs at our institution from January 2010 to October 2016. The independent variables were mandibular third molar (M3) status, age, gender, and preoperative dentofacial diagnosis. The outcome variable was the effectiveness of the sagittal split resulting in either favorable or an unfavorable split. Data analyses were performed using logistic regression models except in the case of small sample sizes of preoperative dentofacial diagnoses for which the Fisher's exact test was used. RESULTS: A total of 888 patients with an average age of 24.97 ± 5.09 years underwent 1,776 SSOs. Sixteen (0.90%) unilateral unfavorable splits occurred. Unfavorable splits were less common in patients with an M3 present than in patients with the M3 absent. Having an M3 present reduced the chance of an unfavorable split by 69%, adjusted for age and gender; OR (95% CI) = 0.308 (0.103, 0.919); P = .035. The odds of having an unfavorable split were increased by 8.8% for every year of age increase; adjusted OR (95% CI) = 1.088 (1.004, 1.178); P = .038. Based on this estimation, a 45-year-old is 2.3 times more likely to have an unfavorable split compared to a 35-year-old (95% CI:1.041, 5.146), and is 5.4 times more likely to have an unfavorable split compared to a 25-year-old (95% CI:1.083, 26.48). CONCLUSIONS: The presence of a mandibular third molar (M3) was associated with a decreased risk of an unfavorable split, independent of age and gender. There was a significant association between increased age and the incidence of an unfavorable split.

Videofluoroscopic Findings as Predictors of Velopharyngeal Insufficiency After Orthognathic Surgery in Patients With Cleft Lip and Palate.

BACKGROUND: Midface retrusion is a common problem in patients with cleft lip and palate owing to the lack of adequate growth of the maxilla. Midface advancement surgery is a definite treatment for midface retrusion; however, the subsequent oropharyngeal airway changes might result in velopharyngeal insufficiency (VPI) in affected patients. Determining the predictors of VPI beforehand and modifying the surgical procedure would be beneficial. MATERIALS AND METHODS: A retrospective review of 42 patients with cleft lip and palate who underwent orthognathic surgery from 2013 to 2014 was performed. A total of 25 patients met the inclusion criteria and had undergone complete pre- and postsurgery videofluoroscopy, nasopharyngoscopy (NPS), and speech assessment. We compared 2 groups of patients, those who showed NPS finding changes of more than 0.1 (8 patients) and those without changes (17 patients), by measuring the distances of the contact point to the tip of the velum, gap size at maximum closure (MC) and rest, contact area length, lateral wall closure rate, closure velocity, and 2 angles (from the velum to the hard palate and genu) at MC and rest. The amount of maxillary advancement was also recorded. RESULTS: Among the 8 patients with NPS finding changes, 3 underwent Furlow palatoplasty for VPI. No significant difference was found in the amount of maxillary advancement between the groups (5.8 vs 5.7 mm). Significant differences were found in the preoperative gap size at MC and angle at the genu at MC (P = 0.035 and .012). These could be considered as the predictors before surgery. After surgery, a significant difference was found in the contact area, lateral wall closure rate, and gap size at MC (P = 0.005, 0.018, and 0.01). CONCLUSION: Videofluoroscopy is a relatively applicable method of determining dynamic changes in the velum function. By performing videofluoroscopy before midface advancement surgery in patients with cleft lip and palate, we may predict the risk of VPI and consider alternative surgical strategies.

Unilateral Cleft Lip Repair Using the Chang Gung Technique: An Outcome Analysis.

OBJECTIVE: This retrospective study analyzed the outcomes of patients undergoing complete or incomplete unilateral cleft lip repair using the Chang Gung technique. The goal was to compare the symmetry and change of the technique through the measurement of anthropometric points on digital photographs. METHODS: From 2010 to 2016, a total of 274 complete and incomplete cleft lip patients without other craniofacial deformities were included in the study. All included patients had a minimum 1-year follow-up with frontal view photographs taken. The vermilion area, lip width, vermilion height, lateral lip length, lip height, and Cupid's bow width of both cleft and noncleft sides were measured for all patients. The Cleft Lip Component Symmetry Index was used to determine the symmetry of the cleft and noncleft sides in both incomplete and complete cleft groups. RESULTS: A total of 152 complete and 122 incomplete cleft lip patients were included in the study. The mean Cleft Lip Component Symmetry Index values showed that the vermilion area, lip height, and Cupid's bow width were symmetric on both cleft and noncleft sides. Lip width and lateral lip length were noted to be shorter, whereas the vermilion height was thicker on the cleft side than on the noncleft side. Significant differences between the complete and incomplete cleft group measurements were found for lateral lip length and lip height, and complete cleft measurements were shorter than those for incomplete clefts. There were no significant differences in vermilion area, lip width, vermilion height, and Cupid's bow width. CONCLUSIONS: The outcome analysis showed that vermilion height reduction and modifications could be made for both complete and incomplete groups. The complete cleft lip has been found to have a significantly shorter lateral lip length and lip height, reflecting a more severe anatomical soft tissue deficiency in this group. A long-term outcome anthropometric point study may further verify the results of this surgical technique.

Impact of the Different Types of Le Fort I Maxillary Surgical Movement on Nasal Width Changes: A Photogrammetric Analysis.

BACKGROUND: Le Fort I maxillary movements affect nasal width, but nasal width changes with specific movement types have not been formally addressed to date. OBJECTIVES: The purpose of this study was to analyze and compare the changes in nasal width with different maxillary movements. METHODS: A retrospective study was performed among consecutive patients who underwent bimaxillary orthognathic surgery (n = 138) and who were grouped based on the type of maxillary movement (ie, maxillary advancement with intrusion [MAI], maxillary advancement with extrusion [MAE], and maxillary setback with intrusion [MSI]). Preoperative and 12-month postoperative nasal widths were analyzed photogrammetrically by 2 blinded evaluators. RESULTS: Maxillary advancement with intrusion and MAE presented a significantly (P < 0.05) higher alar base widening than MSI did, with no significant (P > 0.05) differences between MAI and MAE. Maxillary advancement movements (MAI and MAE) showed significantly (P < 0.05) higher alar base widening than maxillary setback movement (MSI). However, no significant (P > 0.05) difference was observed between maxillary intrusion (MAI and MSI) and maxillary extrusion (MAE) movements. CONCLUSIONS: This study shows that the nasal width varies distinctly depending on the type of Le Fort I maxillary surgical movement.

One-splint versus two-splint technique in orthognathic surgery for class III asymmetry: comparison of patient-centred outcomes.

OBJECTIVES: Two-jaw orthognathic surgery (OGS) is done using either the one-splint technique with free-hand positioning of the maxillomandibular complex or the two-splint technique with intermediate splints to position the maxilla. It is uncertain which technique achieves better outcomes. This study compares frontal soft tissue symmetry and subjective patient QoL between one-splint and two-splint techniques in skeletal Class III asymmetry patients undergoing OGS with three-dimensional surgical planning. MATERIALS AND METHODS: This retrospective case-control study comprised 34 one-splint and 46 two-splint OGS patients. Frontal photographs and Orthognathic Quality of Life Questionnaire (OQLQ) were done pre- and post-treatment. Frontal soft tissue symmetry was analysed with the anthropometric Facial Symmetry Index. Measurements were compared with t-tests and chi-squared tests with p-value set at 0.05. RESULTS: The groups differed in pre-treatment ANB and OQLQ scores. The two-splint group showed significant improvement in all symmetry measures. The one-splint group showed significant improvement in all symmetry measures except midface deviation, upper contour deviation and the Facial Contour Symmetry Index. Both groups showed significant improvement in OQLQ scores. There were no significant differences in post-treatment symmetry measurements and OQLQ scores between groups. CONCLUSIONS: Although two-splint technique may better improve contour symmetry, there were no significant differences in frontal soft tissue symmetry and QoL after OGS in skeletal Class III asymmetry with either one-splint or two-splint technique, with both techniques resulting in significant improvement. CLINICAL RELEVANCE: One-splint and two-splint surgical techniques produce similar patient-centred outcomes in Class III asymmetry patients.

Comparative stability and outcomes of two surgical approaches for correction of class III asymmetry with lip or occlusal cant.

OBJECTIVES: To assess and compare the stability and outcomes of the two surgical approaches for patients with roll asymmetry. MATERIALS AND METHODS: A total of 50 adult patients were consecutively recruited for this prospective study. Patients with class III asymmetry and lip or occlusal cant who underwent bimaxillary surgery were grouped according to surgical approach: asymmetric posterior impaction on both sides (API, n = 31) and posterior impaction on one side and posterior extrusion on the other side (PIE, n = 19). Postsurgical stability and outcomes between groups were determined with cone-beam computed tomography for facial midline, lip, and occlusal cant at 1 week (T1), and at least 12-month postsurgery (T2, completion of orthodontic treatment). RESULTS: Presurgery, the upper anterior occlusal cant and lip cant were significantly greater for the PIE group (p < 0.05). Postsurgery (T2), the mandible moved upward and rotated upward in both groups. However, the upward rotation was significantly greater in the PIE group compared with the API group. Although the two approaches resulted in significant improvements in facial symmetry, the deviation in the facial midline remained under-corrected for most API patients. CONCLUSIONS: Patient outcomes for mandibular stability and facial symmetry differed between the two surgical approaches for correction of class III asymmetry with lip or occlusal cant. CLINICAL RELEVANCE: The findings of this study suggest that planned over-correction is a reasonable option for the approach of asymmetric posterior impaction on both sides.

History and Evolution of Orthognathic Surgery at Chang Gung Craniofacial Center: Lessons Learned From 35-Year Experience.

BACKGROUND: Modern orthognathic surgery (OGS) was established on the basis of contributions from multidisciplinary centers worldwide. This study reports the history and evolution of OGS at the Chang Gung Craniofacial Center (CGCC) and identifies the lessons learned from 35 years of experience. METHODS: The total number of OGS procedures managed by the CGCC multidisciplinary team between 1981 and 2016 was determined. The database of the senior author (Y.-R.C.) was reviewed for consecutive OGS procedures performed between 2003 and 2016. A literature review was also performed to retrieve the contributions from the total CGCC team. RESULTS: The 35 years of experience at a single center and 13-year experience of a single surgeon corresponded to 8073 and 2883 OGS procedures, respectively. Moreover, 53 peer-reviewed articles were reviewed. Teamwork (plastic surgeons, orthodontists, and anesthetists) ensured an optimal balance between occlusion functional and facial aesthetic outcomes, with patient safety ensured and a minimum of OGS-related complications. Progression from the conventional orthodontics-first approach to the surgery-first OGS approach decreased the overall treatment time. Transition from 1-jaw to 2-jaw surgery enabled more consistent aesthetic outcomes to be achieved. Conversion from the 2-splint to the single-splint technique enabled development of a more precise tridimensional simulation plan and surgical execution, including in challenging scenarios such as malocclusion associated with facial asymmetry. Clockwise pitch rotation of the maxillomandibular complex has been designed for facial aesthetic purposes in class III malocclusion, whereas counterclockwise pitch rotation of the maxillomandibular complex improves airway function in those with sleep apnea. CONCLUSIONS: The lessons learned from experience and outcome-based articles reveal that OGS has successfully evolved at the CGCC, with a balance being achieved between functional and aesthetic outcomes and effective decreases in the burden of care (ie, morbidity, complications, and treatment time).

A new 3D analysis on displacement of proximal segment after bilateral sagittal split osteotomy for class III asymmetry.

OBJECTIVES: We aimed to quantify the displacement of the proximal segment after bilateral sagittal split osteotomy in patients with class III asymmetry and evaluate if the displacement was related to the movement of the distal segment. MATERIAL AND METHODS: Forty adults with class III asymmetry corrected by bimaxillary surgery were studied. Cone-beam computed tomography taken before and 1 week after surgery was used to measure the displacement of proximal segments and movement of the distal segment in terms of translation and rotation. The relationship between the displacemnt of the proximal segment and the movement of the distal segment was evaluated. RESULTS: After surgery, the deviated proximal segment was displaced forward and to the deviated side, rotated downward, tilted, and turned to the opposite side. The opposite proximal segment was displaced forward and rotated downward. The roll rotation of the proximal segment was correlated with the left/right movement and roll rotation of the distal segment. CONCLUSION: Early after orthognathic correction for class III asymmetry, the deviated proximal segment was displaced in a direction favorable for correction of asymmetry. The roll rotation of the proximal segment was affected by the transverse movement and roll rotation of the distal segment. CLINICAL RELEVANCE: Knowledge of the ability and limitation of the proximal segment rotation improves the virtual simulation.

The Medial Subcoronoid Process Region as a Novel Source of Bone Grafts in Orthognathic Surgery and Genioplasty.

BACKGROUND: Since 2012, the authors have adopted the medial subcoronoid process bone interpositional grafting in OGS and genioplasty procedures. The purpose of this study was to present the technical details and clinical outcomes of this alternative bone interpositional grafting for LeFort I and chin osteotomies. METHODS: Consecutive patients (n = 50) who underwent single-splint bimaxillary OGS with or without genioplasty and received medial subcoronoid bone interpositional grafting were included. Standardized facial and intraoral photographs at early and late postoperative periods (12.2 ±â€Š3.3 and 44.8 ±â€Š8.4 months postsurgery, respectively) were blindly rated to assess facial symmetry, chin, and occlusion status based on qualitative rating scales. Complication and reoperation rates were also reviewed. RESULTS: The medial subcoronoid bone interpositional grafts were adopted to stabilize different LeFort I maxillary movement types or lengthening/advancing genioplasty (36 and 14 patients, respectively). Overall, the early facial symmetry, chin, and occlusion status were maintained at late evolutions. None of the patients had donor-site or bone graft-related complications (i.e., bad split, undesired mandible fracture, infection, fibrous union, nonunion, and/or permanent neurosensory deficit) or revisionary surgery during follow-up. CONCLUSION: The medial subcoronoid process bone grafting was a feasible alternative for bone interpositional defects of LeFort I and chin osteotomies with no significant morbidity and avoiding secondary donor sites.

Long-term outcomes of bimaxillary surgery for treatment of asymmetric skeletal class III deformity using surgery-first approach.

OBJECTIVES: Although several studies have reported the advantages of the surgery-first approach for orthognathic correction of Class III deformity, there are few reports of the success of this approach for patients with facial asymmetry. Therefore, the purpose of this study was to evaluate the outcome of bimaxillary surgery for asymmetric skeletal Class III deformity using a surgery-first approach. MATERIALS AND METHODS: Sixty-five patients who consecutively underwent at least a combined Le Fort I and a bilateral sagittal split osteotomy for asymmetric skeletal Class III deformity were identified in the authors' patient database. Standardized frontal photographs were used to measure the change in midface, intercommissural line, chin from midface, and chin deviation angles as well as upper, middle, and lower contour deviation angles. The facial midline symmetry index, facial contour symmetry index, and overall facial symmetry index were also calculated. Self-reported questionnaires regarding overall appearance and satisfaction with facial areas were administered at least 1 year post-surgery. RESULTS: Forty-six patients had genioplasty. There was a statistically significant improvement in the deviation angles measured and the facial midline, facial contour, and overall facial symmetry index. Self-reported questionnaires, completed at least 1 year post-surgery, showed that patient satisfaction was high. CONCLUSIONS: These findings demonstrate that the surgical-orthodontic treatment with surgery-first approach can successfully maintain or improve facial symmetry. CLINICAL RELEVANCE: The surgery-first approach for improving facial asymmetry using the guidelines described for setups of the models is a feasible alternative to the classic orthodontic-first approach for bimaxillary orthognathic surgery.

Effects of Hypotensive Anesthesia on Reducing Intraoperative Blood Loss, Duration of Operation, and Quality of Surgical Field During Orthognathic Surgery: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

PURPOSE: The objective of this study was to evaluate the efficacy of hypotensive anesthesia in reducing intraoperative blood loss, decreasing operation time, and improving the quality of the surgical field during orthognathic surgery. A systematic review and meta-analysis of randomized controlled trials addressing these issues were carried out. MATERIALS AND METHODS: An electronic database search was performed. The risk of bias was evaluated with the Jadad Scale and Delphi List. The inverse variance statistical method and a random-effects model were used. RESULTS: Ten randomized controlled trials were included for analysis. Our meta-analysis indicated that hypotensive anesthesia reduced intraoperative blood loss by a mean of about 169 mL. Hypotensive anesthesia was not shown to reduce the operation time for orthognathic surgery, but it did improve the quality of the surgical field. Subgroup analysis indicated that for blood loss in double-jaw surgery, the weighted mean difference favored the hypotensive group, with a reduction in blood loss of 175 mL, but no statistically significant reduction in blood loss was found for anterior maxillary osteotomy. If local anesthesia with epinephrine was used in conjunction with hypotensive anesthesia, the reduction in intraoperative blood loss was increased to 254.93 mL. CONCLUSIONS: Hypotensive anesthesia was effective in reducing blood loss and improving the quality of the surgical field, but it did not reduce the operation time for orthognathic surgery. The use of local anesthesia in conjunction with hypotensive general anesthesia further reduced the amount of intraoperative blood loss for orthognathic surgery.

Concomitant Third Molar Removal During Sagittal Split Osteotomy of the Mandible.

It is described in textbook about management of third molar in orthognathic surgery that "ideally, the third molars should be removed 9 to 12 months before sagittal split osteotomy (SSO)." At the Chang Gung Craniofacial Center, the authors always remove mandibular third molars during SSO, because: removal of third molars at the same time of SSO could reduce psychological stress on patients by saving 1 surgical procedure under local anesthesia, better exposure of impacted third molars could be facilitated by sagittal split of buccal cortical plate, rigid fixation could be performed without difficulty by our fixation method using plates and screws crossover anterior oblique line. Strong force during the elevation of third molars, however, may result in the fracture of distal segment of SSO, where the buccal cortical plate is relatively thin because of the presence of third molar. Therefore, more care needs to be taken in the surgical technique, which is different from ordinary tooth extraction. In this paper, the details of surgical procedure of third molar removal during SSO were reported.