Facial Palsy after Orthognathic Surgery: Incidence, Causative Mechanism, Management, and Outcome.

BACKGROUND: Facial palsy after orthognathic surgery is an uncommon but serious complication causing dissatisfaction and affecting quality of life. The occurrence could be underreported. Surgeons need to recognize this issue regarding the incidence, causative mechanism, managements, and outcome. METHODS: A retrospective review of orthognathic surgery records between January of 1981 and May of 2022 was conducted in the authors' craniofacial center. Patients who developed facial palsy after the surgery were identified, and demographics, surgical methods, radiologic images, and photographs were collected. RESULTS: A total of 20,953 sagittal split ramus osteotomies (SSROs) were performed in 10,478 patients. Twenty-seven patients developed facial palsy, resulting in an incidence of 0.13% per SSRO. In a comparison of SSRO technique, the Obwegeser-Dal Pont technique using osteotome for splitting had higher risk of facial palsy than the Hunsuck technique using the manual twist splitting ( P < 0.05). The severity of facial palsy was complete in 55.6% of patients and incomplete in 44.4%. All patients were treated conservatively, and 88.9% attained full recovery in a median duration of 3 months [interquartile range (IQR), 2.75 to 6 months] after surgery, whereas 11.1% attained partial recovery. Initial severity of facial palsy predicted the timing of recovery, with incomplete palsy patients having faster median recovery (3 months; IQR, 2 to 3 months) than the complete palsy patients (6 months; IQR, 4 to 6.25 months) ( P = 0.02). CONCLUSIONS: The incidence of facial palsy after orthognathic surgery was 0.13%. Intraoperative nerve compression was the most likely causative mechanism. Conservative treatment is the mainstay of therapeutic strategy, and full functional recovery was anticipated. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, IV.

Implementation of an Attention Mechanism Model for Facial Beauty Assessment Using Transfer Learning.

An important consideration in medical plastic surgery is the evaluation of the patient's facial symmetry. However, because facial attractiveness is a slightly individualized cognitive experience, it is difficult to determine face attractiveness manually. This study aimed to train a model for assessing facial attractiveness using transfer learning while also using the fine-grained image model to separate similar images by first learning features. In this case, the system can make assessments based on the input of facial photos. Thus, doctors can quickly and objectively treat patients' scoring and save time for scoring. The transfer learning was combined with CNN, Xception, and attention mechanism models for training, using the SCUT-FBP5500 dataset for pre-training and freezing the weights as the transfer learning model. Then, we trained the Chang Gung Memorial Hospital Taiwan dataset to train the model based on transfer learning. The evaluation uses the mean absolute error percentage (MAPE) value. The root mean square error (RMSE) value is used as the basis for experimental adjustment and the quantitative standard for the model's predictive. The best model can obtain 0.50 in RMSE and 18.5% average error in MAPE. A web page was developed to infer the deep learning model to visualize the predictive model.

Craniofacial Growth and Asymmetry in Newborns: A Longitudinal 3D Assessment.

OBJECTIVE: To evaluate the development of the craniofacial region in healthy infants and analyze the asymmetry pattern in the first year of life. METHODS: The participants were grouped by sex and age (1, 2, 4, 6, 9, and 12 months) to receive three-dimensional (3D) photographs. Stereoscopic craniofacial photos were captured and transformed into a series of craniofacial meshes in each group. The growth patterns of the anthropometric indices and the degree of craniofacial asymmetry were measured, and average craniofacial meshes and color-asymmetry maps with craniofacial asymmetry scores were calculated. RESULTS: A total of 373 photographs from 66 infants were obtained. In both genders, the highest and lowest growth rates for all anthropometric indices were noted between 1 and 2 months and between 9 and 12 months, respectively. Overall, male infants had higher anthropometric indices, head volume, and head circumference than female infants. The craniofacial asymmetry score was presented with a descending pattern from 1 to 12 months of age in both sex groups. Both sex groups showed decreased left-sided laterality in the temporal-parietal-occipital region between 1 and 4 months of age and increased right frontal-temporal prominence between 6 and 12 months of age. CONCLUSIONS: A longitudinal evaluation of the craniofacial growth of healthy infants during their first year of life was presented.

Progressive Comparison of Density Assessment of Alveolar Bone Graft in Patients with Unilateral and Bilateral Cleft.

(1) Background: Continuing to observe the grafted bone mineral density (BMD) is essential to ensure the success of alveolar bone grafting (ABG) in patients with cleft lip and palate. This study elaborates on three methods that can be used to evaluate the progressive BMD. (2) Methods: Forty patients with unilateral or bilateral clefts receiving ABG were enrolled. Cone beam computed tomography (CBCT) scans were taken at 6 months (T1) and 2 years (T2) postoperatively. In CBCT, measurements were obtained on three different planes using the circle located 1 mm from the adjacent teeth (Method A), the largest circle within the defect (Method B), or the central circle with a diameter of 2 mm (Method C). The BMD was the average density of the three planes and was adjusted by pogonion density. Bland-Altman plots were used to evaluate the agreement of each method. Inter-rater reliability was confirmed by the intraclass correlation coefficient (ICC). (3) Results: For Method A, B, and C, the mean-adjusted BMD (BMD/pogonion density, BMDa) was 17.44%, 17.88%, and 17.69%, respectively, at T1 (p = 0.495), and 22.51%, 22.87%, and 22.74%, respectively, at T2 (p = 0.690); the density enhancement rates were 40.54%, 38.92%, and 43.15% (p = 0.382). Significant differences between the BMDa at T1 and T2 were observed (p < 0.001, <0.001, and 0.001, for Method A, B, and C, respectively). The volume of the grafted tissue remained stable during T1 and T2, and no significant correlation between density enhancement rate and volume loss was observed. (4) Conclusions: A significant increase in the BMD of grafted tissue was observed in the 2-year postoperative follow-up. The three methods for measuring BMDa via CBCT can be applied in post-ABG evaluations.

On construction of transfer learning for facial symmetry assessment before and after orthognathic surgery.

Orthognathic surgery (OGS) is frequently used to correct facial deformities associated with skeletal malocclusion and facial asymmetry. An accurate evaluation of facial symmetry is a critical for precise surgical planning and the execution of OGS. However, no facial symmetry scoring standard is available. Typically, orthodontists or physicians simply judge facial symmetry. Therefore, maintaining accuracy is difficult. We propose a convolutional neural network with a transfer learning approach for facial symmetry assessment based on 3-dimensional (3D) features to assist physicians in enhancing medical treatments. We trained a new model to score facial symmetry using transfer learning. Cone-beam computed tomography scans in 3D were transformed into contour maps that preserved 3D characteristics. We used various data preprocessing and amplification methods to determine the optimal results. The original data were enlarged by 100 times. We compared the quality of the four models in our experiment, and the neural network architecture was used in the analysis to import the pretraining model. We also increased the number of layers, and the classification layer was fully connected. We input random deformation data during training and dropout to prevent the model from overfitting. In our experimental results, the Xception model and the constant data amplification approach achieved an accuracy rate of 90%.

Automatic Assessment of 3-Dimensional Facial Soft Tissue Symmetry Before and After Orthognathic Surgery Using a Machine Learning Model: A Preliminary Experience.

PURPOSE: An objective and quantitative assessment of facial symmetry is essential for the surgical planning and evaluation of treatment outcomes in orthognathic surgery (OGS). This study applied the transfer learning model with a convolutional neural network based on 3-dimensional (3D) contour line features to evaluate the facial symmetry before and after OGS. METHODS: A total of 158 patients were recruited in a retrospective cohort study for the assessment and comparison of facial symmetry before and after OGS from January 2018 to March 2020. Three-dimensional facial photographs were captured by the 3dMD face system in a natural head position, with eyes looking forward, relaxed facial muscles, and habitual dental occlusion before and at least 6 months after surgery. Three-dimensional contour images were extracted from 3D facial images for the subsequent Web-based automatic assessment of facial symmetry by using the transfer learning with a convolutional neural network model. RESULTS: The mean score of postoperative facial symmetry showed significant improvements from 2.74 to 3.52, and the improvement degree of facial symmetry (in percentage) after surgery was 21% using the constructed machine learning model. A Web-based system provided a user-friendly interface and quick assessment results for clinicians and was an effective doctor-patient communication tool. CONCLUSIONS: This work was the first attempt to automatically assess the facial symmetry before and after surgery in an objective and quantitative value by using a machine learning model based on the 3D contour feature map.

Strategic management of the minor-form and microform cleft lip: A long-term outcome assessment.

OBJECTIVE: The treatment of the lesser form cleft lip deformity (i.e., minor-form, microform, and mini-microform) is challenging to achieve patient satisfaction. There are no studies investigating how treatment outcomes balance patients' expectations and satisfaction with surgical or non-surgical care relative to the initial nasolabial findings. METHODS: Based on Mulliken's classification, consecutive records of patients with the lesser-form cleft lip from 1990 to 2015 were selected for analysis. Demographics, management, and revisions were reviewed. A panel analysis was performed based on the ratings from both professionals and non-professionals using patients' photographs. FACE-Q questionnaires were used to compare patient/parent-reported satisfaction to the normal controls. RESULTS: A total of 135 patients were included. All of the minor-form (23/23), 89% (58/65) of the microform, and 62% (29/47) of the mini-microform patients underwent surgery. Fifty-two percent (15/29) of the mini-microform patients, who underwent surgery, showed no significant improvement. Post-operative upper lip scars and remaining nasal asymmetry were the most common concerns in the treatment group. However, the FACE-Q results showed that patients experienced a statistically significant improvement in their overall facial appearance and social function in their respective groups. CONCLUSIONS: This study showed that differences exist in the perception of facial esthetics between the surgeon and the patient/parent. To achieve optimal individual treatment outcome and patient satisfaction, an awareness of the differences and treatment selection for patients are critical in surgical planning. This understanding and an open detailed discussion of overall long-term outcomes help in the management of patient expectations.

Measuring patient-reported outcomes in orthognathic surgery: Linguistic and psychometric validation of the Mandarin Chinese version of FACE-Q instrument.

BACKGROUND: Orthognathic surgery is useful for correction of dental malocclusion and improvement of facial appearance. The FACE-Q is a patient-reported outcome instrument for evaluation of surgical and psychosocial effect. The purposes of this study were to conduct a linguistic validation of all FACE-Q scales to Mandarin Chinese, to test the orthognathic surgery-related scales for reliability and validity, and to evaluate the effect of orthognathic surgery. METHODS: All FACE-Q scales and checklists were translated from English to Mandarin Chinese according to international recommendations: forward translations, backward translation, and cognitive interviews. Psychometric testing of orthognathic surgery-related scales of translated version was administered to patients with facial deformities and history of orthognathic surgery (n = 53; 17 scales) or no history of orthognathic surgery (n = 44; 11 scales), and control subjects (n = 57; 11 scales). RESULTS: All FACE-Q scales and checklists were linguistically validated into Mandarin Chinese. The contents were confirmed valid among Mandarin Chinese-speaking population. The FACE-Q scales had excellent internal consistency (Cronbach's alpha >0.70) and discriminated (p < 0.05) well between patients before and after orthognathic surgeries and normal subjects. CONCLUSIONS: This study discovered significant benefit of orthognathic surgery on improving facial appearance and psychosocial function, as compared with the non-surgical patients and normal controls.

The Impacts of Orthognathic Surgery on the Facial Appearance and Age Perception of Patients Presenting Skeletal Class III Deformity: An Outcome Study Using the FACE-Q Report and Surgical Professional-Based Panel Assessment.

BACKGROUND: A recent artificial intelligence-based investigation has shown the impacts of orthognathic surgery on the patient's facial appearance and apparent age. However, appearance and age perception as reported by patients and surgical professionals have not been addressed in the same cohort to date. METHODS: FACE-Q facial appraisal (appearance and age) and quality-of-life scale scores obtained before and after orthognathic surgery, in addition to three-dimensional photographs of 70 patients with skeletal class III deformity, were collected for a comparative cross-sectional study. Seven blinded plastic surgeons rated all photographs for apparent facial aesthetic and age scales. The FACE-Q data from 57 matched normal individuals were adopted for the comparative analyses. The correlation between the FACE-Q and the professional-based scales was tested. RESULTS: Pre-orthognathic surgery versus post-orthognathic surgery comparisons showed significant differences (p < 0.001) for all FACE-Q scales and panel assessments, with higher (FACE-Q scales and professional-based aesthetic parameters) and lower (FACE-Q patient-perceived age scale and professional-based age parameter) values for post-orthognathic surgery measurements. Patients had significantly (p < 0.001) higher (patient-perceived age scale) and lower (facial appraisal and quality-of-life scales) FACE-Q values than normal individuals for pre-orthognathic surgery but not for post-orthognathic surgery measurements. The FACE-Q facial appearance overall scale had significant correlations (p < 0.001) with the panel assessment for the parameters "beautiful" and "attractive" but not for the "pleasant" parameter. No significant correlations were observed for facial age scales. CONCLUSION: This study contributes to the orthognathic surgery literature by revealing that orthognathic surgery positively impacts the perception of apparent facial age and improves facial appearance and quality of life. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Fat Grafting in Patients With Extensive Unilateral Facial Deficiency: Three-Dimensional Computer-Assisted Planning, Implementation, and Outcome Assessment.

PURPOSE: Autologous fat injection is a widely used, simple, and less invasive technique to correct volume deficiency. This study developed a treatment method by using a 3-dimensional (3D) simulation to plan and implement fat injection in patients with an extensive facial deficiency and then validated the accuracy of the method and treatment outcomes. METHODS: Seven patients with a large unilateral facial deficiency receiving autologous fat grafts between 2015 and 2017 were recruited. One patient received repeated treatment. Furthermore, 3D surgical simulation was used to measure the difference between the mirrored image and lesion side. An extra 20% to 30% of fat graft was added. A color map was provided, and contour lines 2 mm deep marked the location of the fat injection. Outcome assessments were then performed, and a 3D symmetry index was defined using the contour lines on the facial surface. RESULTS: No significant difference was noted between the predicted volume and postoperative fat graft retention (35.7 ± 7.4 and 31.6 ± 9.7 mL, respectively; P = 0.176). A comparison of preoperative (79.5% ± 4.3%) and postoperative (89.0% ± 3.3%) 3D symmetry indexes indicated significantly improved facial symmetry (P = 0.018). Patient-reported outcomes of satisfaction on FACE-Q questionnaires yielded an average score of 62.73, higher than the control score (59.83). CONCLUSIONS: By using the proposed method, we could predict the required fat graft volume; moreover, the contoured map aided accurate surgical implementation. Thus, this method is useful for planning and guiding fat grafting treatment in patients with major unilateral facial deficiency.

Identifying Three-Dimensional Facial Fluctuating Asymmetry in Normal Pediatric Individuals: A Panel Assessment Outcome Study of Clinicians and Observers.

This study measured three-dimensional facial fluctuating asymmetry in 600 normal and healthy Taiwanese individuals (6 to 12 years old) and assessed the perceptions of increasing levels of facial fluctuating asymmetric severity by using a panel composed of 20 clinicians (surgical professionals), as well as 20 adult and 40 pre-adolescent observers. On average, this normal cohort presented a facial fluctuating asymmetry of 0.96 ± 0.52 mm, with 0.52 ± 0.05, 0.67 ± 0.09, 1.01 ± 0.10, and 1.71 ± 0.36 mm for levels I, II, III, and IV of severity, respectively. For all categories of raters, significant differences in the average symmetry-asymmetry scale values were observed, with level I < level II < level III = level IV (all p < 0.01, except for level III vs. IV comparisons with p > 0.05). For level I, pre-adolescent observers presented a significantly (p < 0.05) higher symmetry-asymmetry scale value than adult observers, with no significant (all p > 0.05) differences for other comparisons. For overall facial asymmetry and levels II, III, and IV, no significant (all p > 0.05) differences were observed. This study reveals that the normal pediatric face is asymmetric and the panel assessment of facial fluctuating asymmetry was influenced by the level of severity and the category of raters and contributes to the literature by revealing that pre-adolescent raters present a similar or higher perception of facial asymmetry than adult raters.

Investigate the oral health impact and quality of life on patients with malocclusion of different treatment needs.

BACKGROUND: This study compared oral health impacts and QoL among patients with different malocclusion types and a normal population by using self-report questionnaires. METHODS: In this cross-sectional study, 214 healthy adults were divided into 3 groups: (1) Normal, control group; (2) ORTHO, patients who received orthodontic treatment; and (3) OGS group, patients who received orthognathic surgery (OGS). The timing of measurement were at the initial stage of the orthodontic therapy and before surgery. Two questionnaires and one additional item were used: the 36-item Short Form Health Survey (SF-36) for QoL, the 14-item Oral Health Impact Profile (OHIP-14) for oral health-related QoL (OHRQOL) and one additional item for aesthetic evaluation. Descriptive and inferential statistical analyses were used to compare the 3 groups. The effects of 3 malocclusion types, gender, age, and facial asymmetry in the OGS group were also evaluated. RESULTS: The ORTHO and OGS groups had higher negative impacts than did the Normal group in the OHIP-14, but not much difference in the SF-36. The item of aesthetics related to oral health impact was the lowest in the OGS group. The patients in the ORTHO group with a Class II malocclusion were most dissatisfied in the SF-36 and OHIP-14. In the OGS group, the women dissatisfied in the OHIP-14 and the aesthetic. The older patients had higher negative impacts in the OHIP-14 than the younger patients. The patients with facial asymmetry did not suffer higher negative impacts than did the patients with a symmetrical face in the SF-36 and OHIP-14. CONCLUSIONS: The majority of the patients who required orthodontics or OGS reported a higher negative impact in the OHIP-14 compared with the normal controls, but not in the SF-36. Class II malocclusion suffered from highest psychological stress and aesthetic sensitivity than the other two subgroups in the ORTHO group.

The Effectiveness of an International Cleft Mission Model in Asia: An Update.

BACKGROUND: Cleft lip/palate is a congenital craniofacial anomaly affecting patients physically and psychosocially and has contributed to the global burden of surgical disease, especially in underprivileged areas. For 20 years, Noordhoff Craniofacial Foundation (NCF) and the Chang Gung Craniofacial Center (CGCFC) have carried out missions to these areas. Rather than implementing short-term missions that lack proper follow-up care, the team has provided an effective, long-term, and multidisciplinary approach for the treatment of patients with cleft lip/palate. In this study, we evaluate the sustainability and effectiveness of the cleft mission model implemented by NCF and CGCFC. METHODS: Data from the years 1998-2017 were retrieved from the NCF database. All local centers were evaluated by a 3-stage categorization, levels 1 to 3, based on 4 criteria: (1) capacity to carry out independent missions, (2) diversity of cleft-care professionals, (3) diversity of surgical service offered, and (4) collaboration with local hospitals. Support and training of personnel were provided based on deficiency in these criteria. Noordhoff Craniofacial Foundation made close collaborations and partnerships with several organizations that shared its mission for comprehensive cleft care in developing countries. RESULTS: In all, 19 partner cleft teams in 9 different countries were established. In coordination with these teams, NCF and CGCFC have treated 1846 patients across 78 mission trips. To date, 158 personnel from 19 different countries have been successfully trained to provide cleft care in local centers. Most partner cleft teams centers have progressively reached category level 3, including those in the Philippines, Cambodia, and Mongolia. CONCLUSIONS: In order to establish and maintain sustainable cleft care in developing regions, commitment and compassion toward those who lack essential resources are necessary. Noordhoff Craniofacial Foundation and CGCFC have achieved a successful and practicable model through seeding medical personnel in order to provide effective and sustainable cleft care to the regions in need.

Perception of Lip Cant as a Sign of Facial Deformity: Assessment by Laypersons and Professionals on Composite Face Photographs.

OBJECTIVE: Lip cant is a feature of facial deformity and commonly seen in patients with facial asymmetry. Because of its importance in aesthetic assessment, it is necessary to define the perceptions of lip cant and investigate differences in perception between laypersons and professionals. These data were insufficient in the literature. METHODS: Photographs of 30 male and 30 female individuals with normal faces were collected, and the lip line angles were measured. A composite facial photograph was generated from superimpositions of the normal faces. Lip line angles from 0° to 9° were made, with other facial features remaining unchanged. The test photographs were arranged in random fashion and evaluated by 64 laypersons and 30 professionals. Comparisons and cumulative frequency were performed. RESULTS: The lip line angle from the 60 normal persons was 1.20° ± 0.94°. From the composite test photographs, the average first perception of lip cant was 3.25° 1± 1.36° in the laypersons and 1.70° ± 0.69° in the professionals. The average first perception of unacceptable lip cant was 6.40° ± 1.79° in the laypersons and 4.40°1. ± 1.65° in the professionals. Significant differences were found between the first perception and perception as unacceptable lip cant, as well as between the laypersons and the professionals. Cumulative data showed that 82.8% of the laypersons perceived lip cant at 4°, and 17.2% of them felt it aesthetically unacceptable. Few laypersons (1.6%) considered less than 4° unacceptable. CONCLUSIONS: The data in this study provide helpful information in the evaluation of lip cant. A lip cant of 4° or more could be considered an indication for clinical management.

Predicting need for orthognathic surgery in early permanent dentition patients with unilateral cleft lip and palate using receiver operating characteristic analysis.

INTRODUCTION: The purpose of this study was to predict the need for orthognathic surgery in patients with unilateral cleft lip and palate (UCLP) in the early permanent dentition. METHODS: In this retrospective cohort study, we included 61 patients with complete UCLP (36 male, 25 female; mean age, 18.47 years; range, 16.92-26.17 years). The subjects were grouped into an orthognathic surgery group and a nonsurgery group at the time of growth completion. Lateral cephalograms obtained at the age of 11 years were analyzed to compare the 2 groups. The receiver operating characteristic analysis was applied to predict the probability of the need for orthognathic surgery in early adulthood by using the measurements obtained at the age of 11 years. RESULTS: SNB, ANB, SN, overbite, overjet, maxillary length, mandibular body length, and L1-MP were found to be significantly different between the 2 groups. For a person with a score of 2 in the 3-variable-based criteria, the sensitivity and specificity for determining the need for surgical treatment were 90.0% and 83.9%, respectively (ANB, ≤-0.45°; overjet, ≤-2.00 mm; maxillary length, ≤47.25 mm). CONCLUSIONS: Three cephalometric variables, the minimum number of discriminators required to obtain the optimum discriminant effectiveness, predicted the future need for orthognathic surgery with an accuracy of 86.9% in patients with UCLP.

Primary Repair in Patients With Unilateral Complete Cleft of Lip and Primary Palate: Assessment of Outcomes.

OBJECTIVE: Asymmetry of median facial structures is a major concern for patients with unilateral cleft lip and palate, and the principal goal of its treatment is to restore symmetry. Unilateral complete cleft of lip and primary palate (UCCLPP) is an uncommon subgroup and rarely reported. Patients with UCCLPP have protruding and deviating premaxilla, rendering a primary repair difficult. This study evaluated consecutive patients with UCCLPP and presented their treatment outcome. METHODS: We assessed 36 patients with UCCLPP and collected clinical information. Surgical repair was performed at 3 months of age by using a modified rotation-advancement method and primary nasal reconstruction. A single surgeon performed all surgical procedures. A postoperative nasal stent was used for 6 months. Follow-up standardized photographs were collected. Landmarks were identified, and nose and lip dimensions measured. The ratios of the corresponding parameters (cleft vs noncleft side) were obtained for evaluating nose and lip symmetry. RESULTS: No surgical complication was noted in any patient. The overall lip and nose outcome after the primary repair were adequate, and all ratios were close to 1. The nostril width was slightly wider on the cleft side, but the alar width and height were acceptable. The lip heights were balanced between the 2 sides. Patients who received presurgical nasoalveolar molding did not show more favorable lip and nose dimensions, except for the medial philtral height. CONCLUSION: Even in the presence of protruding and deviating premaxilla, our patients with UCCLPP obtained adequate lip and nose outcome after undergoing primary lip repair and nasal reconstruction.

A Modified Technique of Mandibular Ramus Sagittal Split Osteotomy for Prevention of Inferior Alveolar Nerve Injury: A Prospective Cohort Study and Outcome Assessment.

BACKGROUND: Postoperative functional impairment of the inferior alveolar nerve (IAN) has been a common and well-recognized complication. Our study introduced a modified Obwegeser-Dal Pont bilateral sagittal split osteotomy (BSSO) technique and evaluated the subsequent incidence of postoperative neurosensory disturbance of IAN. METHODS: In this prospective cohort study, 57 patients receiving our modified BSSO during orthognathic surgery were enrolled. The technique contained opening the 2 ramus cortices and inserting the osteotome bypassing the IAN to avoid nerve injury. A 5-point scale self-assessment questionnaire was used to evaluate IAN neurosensory disturbance one week, six months and 12 months postoperatively. Differences between groups were analyzed using χ test for categorical and Wilcoxon signed-rank test for pairwise categorical data. RESULTS: Complete ramus splitting could be achieved in 109 (95.6%) sides. Lower lip or chin neurosensory disturbances presented in 72 (63.2%) sides 1 week postoperatively and gradually reduced to 9 (7.9%), and 4 (3.5%) at postoperative months 6 and 12, respectively. CONCLUSIONS: This BSSO technique could be safely performed with low rates of IAN exposure and injury and a low incidence of persistent neurosensory disturbance in 3.5% of patients 12 months postoperatively.

Assessment of blood loss and need for transfusion during bimaxillary surgery with or without maxillary setback.

PURPOSE: The objective of this study was to compare the blood loss, transfusion needs, and operation times in subjects who underwent bimaxillary surgery with versus without maxillary setback. MATERIALS AND METHODS: A retrospective chart review was completed in all patients who underwent bimaxillary surgery from March 2009 to August 2010. The inclusion criterion was the availability of a complete chart record. Patients were divided into 1 of 2 groups based on maxillary setback procedure. The predictive variable was the treatment group. The primary outcome variable was blood loss as measured by the change in hemoglobin. The secondary outcome variables were operation time and transfusion need. The other study variables were a patient's characteristics (ie, age and gender). Mann-Whitney test was performed to compare unpaired samples. Student t test was performed to compare operation time. Multiple regression analysis was used to analyze the adjusted relation among the study variables. RESULTS: There were 82 patients (17 male and 65 female; mean age, 28.0 ± 4.9 yr; age range, 18 to 35 yr) who underwent bimaxillary surgery in this study. The mean hemoglobin decreases were 1.72 g/dL (standard deviation, 0.67 g/dL) in the nonsetback group and 2.37 g/dL (standard deviation, 0.76 g/dL) in the setback group. The average operation times were 158.24 ± 30.36 minutes (range, 127.88 to 188.6 min) in the nonsetback group and 194.35 ± 29.20 minutes (range, 165.15 to 223.55 min) in the setback group. Transfusion was not performed in any patient. After adjusting for potential factors, the multiple regression model showed that the treatment group was associated with blood loss (P < .0001) and operation time (P < .0001). CONCLUSIONS: This study shows that intraoperative bleeding and operation time increased significantly in patients undergoing mandibular ramus osteotomy and Le Fort I osteotomy with maxillary setback. However, transfusion generally is not required during 2-jaw surgery, regardless of maxillary setback.