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The aim of this study was to compare two techniques for temporary intraoperative maxillomandibular fixation (TIO-MMF) during orthognathic surgery: steel-wire ligatures versus power chains. Patients undergoing orthognathic surgery between October 2019 and March 2020 were included in a prospective cross-sectional study conducted in three participating hospitals. Data were collected using a standardized measurement form. A total of 44 patients were included, in whom TIO-MMF was applied 79 times. A statistically significant difference in intraoperative loss of stability of the segment relationship was found between steel-wire ligatures (11.4%) and power chains (0%). The mean application time of TIO-MMF differed significantly between steel-wire ligatures (99 seconds) and power chains (157 seconds) (P < 0.001). There was no statistical difference in occurrence of adverse events between the two techniques. This study found that the application of TIO-MMF with power chains is more stable compared to steel-wire ligatures. Steel-wire ligatures were significantly faster to apply, although the absolute difference (less than 1 minute) was small. Other possible advantages of the proposed technique are discussed. The results of this study suggest that power chains for the application of TIO-MMF in orthognathic surgery are a valuable alternative to steel-wire ligatures.

The aim of this randomized controlled trial was to compare the skeletal stability between sagittal split ramus osteotomy (SSRO) and intraoral vertical ramus osteotomy (IVRO) in the treatment of mandibular prognathism. Patients presenting with mandibular prognathism and scheduled for orthognathic surgery were randomized into either the SSRO group or the IVRO group. Changes at B-point were assessed by serial tracing of lateral cephalograms, which were taken preoperatively, and at 2 weeks, 6 months, 1 year, and 2 years postoperatively. Ninety-eight patients were recruited, with 49 patients in each group. Between 2 weeks and 6 months postoperatively, there was significantly more surgical relapse in the horizontal direction (anterior movement) in the SSRO group when compared with the IVRO group (1.83 mm (SD 2.91 mm) vs 0.49 mm (SD 2.32 mm); p = 0.019). At 2 years, there was more surgical relapse in the horizontal direction in the SSRO group than in the IVRO group (0.27 mm (SD 0.34 mm) vs 0.10 mm (SD 0.29 mm); p = 0.014). There were also more absolute changes (irrespective of direction) at B-point in the SSRO group than in the IVRO group at postoperative 6 months, 1 year, and 2 years (p = 0.016, 0.049, and 0.045, respectively). The amounts of change at B-point as percentages of total mandibular setback were 1.3% and 3.5% in the IVRO group and SSRO group, respectively. There were no differences in vertical changes between the two groups at any time points. In conclusion, the horizontal stability at B-point was shown to be superior in the IVRO group compared with the SSRO group in the correction of mandibular prognathism during the 2-year follow-up. Although the exact clinical importance of this difference is unknown at this time, this possible benefit may be an important key factor when deciding which osteotomy technique to employ for mandibular setback.

The traditional 'high and short' medial cut of the sagittal ramus osteotomy (Hunsuck modification) is a frequent cause of lingual plate interferences in patients undergoing mandibular yaw or cant corrections. We describe how the modified 'low and short' medial cut of the sagittal ramus osteotomy reduces lingual plate interferences with improved passive alignment of the osteotomy segments.

Objectives Mandibular defects involving the central segment are challenging. This study analyzes the impact of defect extent and reconstruction method on quality of life (QOL) and obstructive sleep apnea (OSA). Materials and methods Twenty-nine ameloblastoma patients received segmental mandibulectomy involving the C-segment and immediate fibula free flap reconstruction were recruited. Defects: (C: 2, LC: 11, LCL: 19). Mean defect length: 8.79 cm (± 2.34). Inset: Low-single-barrel (n: 19), with secondary distraction osteogenesis (n: 8/19), high-single-barrel (n: 7), double barrel (n: 3). Patients were surveyed using University of Washington Quality of Life (UW-QOL) and Berlin risk of postoperative sleep apnea questionnaires. Results Flap failure: None. Mean follow-up: 109.6 ± 92.8 months. UW-QOL: Physical function 91.83 (± 14.92); social function 90.17 (± 17.19). No statistical difference between C, LC, and LCL was found, but C group which received low-single-barrel had the lowest score in appearance and chewing domains. In health-related QOL (HR-QOL) compared with 1 month before cancer, 69% reported best results. “Appearance” was the most important issue for the past 7 days, followed by “Chewing,” prevailing in LC and C groups that predominately reconstructed by low-single-barrel. Berlin score: 7 patients (4 LCL, 3 LC≥8 cm) were at high risk for postoperative OSA. Conclusion “Like-with-like” reconstruction with immediate endosteal dental implants yields the best results. Inset of fibula bone could affect outcomes, favoring double-barrel or single-high-barrel inset. Appearance and chewing remain the main concerns, largely, in those with low-single-barrel inset and no dental restoration. After long/extensive LCL and LC mandibulectomies, postoperative OSA warrants further investigation, and modification of resection/reconstruction techniques.

Background An augmented reality tool allows visual tracking of real anatomical structures and superimposing virtual images, so it can be used for navigation of important structures during surgery. Objectives The authors have developed a new occlusal splint-based optical navigation system for craniomaxillofacial surgery. In this study, the authors aim to measure the accuracy of the system and further analyze the main factors influencing precision. Methods Ten beagle dogs were selected and a three-dimensional model was established through computed tomography scanning, dental model making, and laser scanning, and then registration was performed according to the tooth marking points. The bilateral mandibular osteotomy was performed on Beagle dogs under navigation system based on the occlusal splint. The left side was taken to compare the deviation between the preoperative plan and the surgical results, and the accuracy of distance and angle and the stability of the system were analyzed. Results The average position deviation between the preoperative design and intraoperative navigation was: 0.01 ± 0.73 mm on the lateral height of the mandibular ramus, 0.26 ± 0.57 mm on the inner height of the mandibular ramus, and 0.20 ± 0.51 mm on the osteotomy length. The average angle deviation is 0.94° ± 1.38° on the angle between the mandibular osteotomy plane and ramus plane and 0.66° ± 0.97° on the angle of the retained mandibular angle. And most of the data showed good consistency. Conclusions In summary, the accuracy of the system can meet clinical requirements and can be used as a useful tool to improve the accuracy of craniomaxillofacial surgery.

The purpose of this study was to compare complication rates at the mandibulotomy site between patients receiving preoperative radiotherapy (RT) and those receiving postoperative RT during treatment for oral and oropharyngeal cancer where the surgical procedure required a mandibular osteotomy to gain access to the tumour. Sixty-four consecutive patients treated during the period 2000-2015 were available for analysis. Their medical records were reviewed retrospectively. All patients were followed for at least 1year postoperatively. A subgroup of patients received RT on several occasions or long before the mandibulotomy, therefore the statistical comparisons focused on the two groups of patients receiving RT on one occasion and within 6 months prior to or following surgery. Seventeen patients presented a total of 29 complications, yielding an overall complication rate of 27%. Orocutaneous fistula was the most common complication. Patients who received RT preoperatively presented a higher complication rate (9/15; 60%) when compared to those who received RT postoperatively (2/31; 6.5%) (odds ratio 21.8, P0.001). This study demonstrated fewer complications in the mandibulotomy area exposed to postoperative RT compared with preoperative RT. It is therefore suggested that, when possible, RT should be given postoperatively if combination treatment with RT and surgery, including a mandibulotomy, is planned.

To compare the masseter muscle changes and bone regeneration between reduction mandibuloplasty along with partial masseter muscle resection and reduction mandibuloplasty alone. Forty-seven patients who complained of prominent mandibular angle and hypertrophy masseter muscles (MMH) were divided into group 1 treated with reduction mandibuloplasty along with partial masseter muscle resection, and group 2 treated with reduction mandibuloplasty alone. Pre-5 days and long-term postoperative computed tomography data were collected, and the masseter muscle volume, hemi-mandible volume, and unilateral lower face width were measured. Patient satisfaction and complication were also evaluated. At long-term follow-up, group 1 showed a greater decrease in masseter volume (p

The present study aimed to investigate how "Gull in Flight" appearance and alar-columellar relationship change following maxillary surgery. Thirty-three patients who underwent Le Fort I osteotomy with or without mandibular osteotomy were included in this retrospective study. Measurements which were angle of columella triangle, alar-rim angle, columella lobular angle, and distance of points forming "Gull in Flight" appearance were evaluated on pre and postoperative frontal and lateral photos of patients. Data was submitted to statistical analysis and significance level was determined as 0.05. Following Le Fort I surgery, distance of points forming "Gull in Flight" appearance with respect to canthus was decreased significantly (P < 0.05). Positions of these points to each other were not changed (P > 0.05). Every 1 mm maxillary impaction led to 0.58 mm reduction in y3 (the distance from the point that illustrates Gull's body) (P = 0.032). There was a decrease in angle of columella triangle, alar-rim angle and increase in columella lobular angle. However, these changes were not found significant (P > 0.05). Angle of columella triangle was increased 2.51 degree for every 1 mm maxillary advancement (P = 0.028). In conclusion, maxillary surgery had an impact on nasal region from frontal view. However, "Gull in Flight" appearance which is one of the aesthetic parameters in nose was not changed following maxillary surgery.

Purpose: The purpose of this study is to examine the association of steroid use during orthognathic surgery and postoperative outcomes including major complications, 90-day all-cause readmission, and postoperative length of stay. Methods: A retrospective review was implemented utilizing the Pediatric Health Information System (PHIS) database from 2004 to 2014 was undertaken. Steroid exposure was defined as having been billed for the generic drug code for Dexamethasone (154035) at any time for up to 7 days from the surgery date. Unadjusted and adjusted random-intercept logistic regression models were utilized to assess the association between steroid exposure and these outcomes. Results: The sample included 5194 patients, 54% of patients were exposed to steroids, with 20.16 % exposed only on the day of surgery, 27.76% on the day of surgery and after, and 6.22% after the day of surgery. In models adjusting for age, sex, race, procedure, hospital variation and complex chronic conditions, the odds-ratio of steroid exposure was 3.46 (95% CI = 2.96-4.03) for an increased length of stay, 1.05 (95% CI = 0.81-1.37) for major complications and 1.20 (95% CI = 0.95-1.52) for 90-day all-cause readmission. Conclusion: The administration of steroids in patients undergoing orthognathic surgery is significantly associated with increased odds of length of stay. This may be due to a large set of patients receiving steroids during orthognathic procedure are less healthy than those not selected to receive steroids, and thereby require an increased length of stay. The limitations of large, administrative databases do not allow determination of this, but future prospective study is warranted.

To evaluate whether the distance between the mandibular occlusal plane and mandibular foramen predicts inferior alveolar nerve (IAN) position after the sagittal split osteotomy (SSO) when using a low medial horizontal osteotomy (Posnick's modification).This was a retrospective cohort study of patients undergoing bilateral SSOs with the medial osteotomy placed at the level of the mandibular occlusal plane. The primary predictor variable was the vertical distance between the mandibular foramen and mandibular occlusal plane. The primary outcome was IAN position after SSO: contained within the proximal segment or freely entering the distal segment. Secondary predictor variables were age, gender, primary diagnosis, and type of surgery. Descriptive, bivariate, and regression statistics were computed.Thirty-one patients underwent 62 SSOs using a low medial cut; the sample's mean age was 19.6 ± 3.0 years, and 16 subjects were female. Twenty-three subjects had a primary diagnosis of craniofacial anomaly, and 26 subjects underwent bimaxillary surgery. The IAN was contained within the proximal segment in 28 SSOs (45.2%). The distance between the mandibular occlusal plane and mandibular foramen was greater in SSOs where the nerve was contained within the proximal segment (6.9 ± 2.5 mm) versus freely entering the distal segment (4.5 ± 2.7 mm, P .001). A receiver-operator characteristic curve identified a threshold distance of greater than 5 mm as predictive of the IAN being contained within the proximal segment (sensitivity, 0.89; specificity, 0.85; area under the curve, 0.84; P .001). When the mandibular foramen was greater than 5 mm above the mandibular occlusal plane, there was an increased odds of the IAN being contained within the proximal segment (odds ratio, 48.3; 95% confidence interval, 10.5, 222.8; P .001).The distance between the mandibular occlusal plane and mandibular foramen predicts the position of the IAN after SSO when using a low medial horizontal osteotomy.

In the surgical procedures such as osteotomy to be applied to ramus of the mandible, care should be taken not to damage the inferior alveolar nerve (IAN). The safe zone, which is the area above and behind the mandibular foramen (MF), is the ramus of mandible area, where these surgeries can be performed without damaging the inferior alveolar neurovascular bundle. It was aimed to determine the safe zone in the ramus of mandible in the cone-beam computed tomography (CBCT) images of individuals. The CBCT images of 300 Turkish individuals between the ages of 18 to 65 were bilaterally and retrospectively evaluated. Three parameters on the sagittal and two parameters on the axial plane were measured. Additionally, two ratios were calculated which determined the superior and posterior part of the safe zone through the measured parameters. In this study, the safe zone was determined as the area where 55% of the upper part and 49% of the posterior part of the mandibular ramus. Determining the safe zone in surgical procedures to be applied to the ramus of mandible will help protect the neurovascular structures passing through the MF, reduce complications and increase the success rate of the surgical procedure. However, it is seen that there are few studies on this subject in the literature and there are some differences between these studies. The authors think that preoperative CBCT screening will be safer for each patient in the mandibular ramus osteotomies and more studies should be done on different populations to determine standard values.

Purpose: 3D-printed cutting guides are the current standard to translate the virtual surgery plan to the intraoperative setting. The production of these patient-specific cutting guides is time-consuming and costly, and therefore, alternative approaches are currently subject of research. The aim of this study was to assess the accuracy and reproducibility of using a novel electromagnetic (EM) navigated surgical cutting guide to perform virtually planned osteotomies in mandible models. Methods: A novel 3D navigated cutting guide (dubbed Bladerunner) was designed and evaluated with a total of 20 osteotomies, performed on plaster mandibular models according to preoperative planning using EM navigation. The pre- and postoperative scans were registered, and the difference between the preoperatively planned osteotomy and the performed osteotomy was expressed as the distance between the planned and performed cutting planes, and the yaw and roll angles between the planes. Results: The mean difference in distance between the planned osteotomy and performed osteotomy was 1.1 mm (STD 0.6 mm), the mean yaw was 1.8° (STD 1.4°), and mean roll was 1.6° (STD 1.3°). Conclusion: The proposed EM navigated cutting guide for mandibular osteotomies demonstrated accurate positioning of the cutting plane according to the preoperative virtual surgical plan with respect to distance, yaw and roll angles. This novel approach has the potential to make the use of 3D-printed cutting guides obsolete, thereby decreasing the interval between diagnosis and surgery, reduce cost and allow for adaptation of the virtual plan in case of rapid tumor proliferation or unanticipated in situ deviations from the preoperative CT/MR imaging.

Objective The aim of this study was to evaluate the relationship between neurosensory disturbance (NSD) and the different types of bilateral sagittal split osteotomy (BSSO) lingual fracture created. Study Design The study group consisted of 45 patients with mandibular deformities (90 sides; 14 males and 31 females). Computed tomography (CT) scans were obtained preoperatively and 1 week postoperatively. All patients were divided into lingual fracture line groups on the basis of their postoperative scans. NSD was tested preoperatively and 1, 3, and 12 months postoperatively by using a sensory touch Semmes-Weinstein (SW) test and the 2-point discrimination (TPD) test. Results Patients were divided into 2 groups on the basis of their lingual fracture lines after mandibular BSSO; among the 45 patients, 39 sides (43.3%) had short-splits, and 51 sides (56.7%) had long-splits. The short-split group was less affected at all tested times, and the difference between the 2 groups was significant 1 month postoperatively on TPD test but not at other times on the both tests. Conclusions The split type did not affect the NSD incidence at 3 and 12 months postoperatively.

After sagittal split osteotomy, the mandibular distal and proximal fragments do not always align themselves passively to one another, resulting in bony interferences and subsequent anomalous settlement of the condyles. Predicting these interferences could be an important ancillary procedure for avoiding intra- and postoperative surgical complications, rendering orthognathic surgery more effective and safer. This study evaluated the relevance of virtual surgical planning in assessing the displacement of the proximal segments after virtual distal segment repositioning, for predicting bony interferences between the segments and thus avoiding related intra- and postoperative surgical complications. The presence of interferences between the distal and proximal segments was compared between virtually predicted (computer-assisted simulation surgery, Dolphin software) and real cases in 100 consecutive patients diagnosed with dentofacial deformities who underwent orthognathic surgery with mandibular repositioning (using a short lingual osteotomy (SLO)). The results indicated that clockwise rotation of the mandible was the mandibular movement most prone to segment interference. Furthermore, virtual planning was sensitive (100%) but had low specificity (51.6%) in predicting proximal and distal segment interferences. This low specificity was due to the software-based automated design of the mandibular osteotomy, where the length of the distal segment was longer than the real SLO, and the mandibular ramus sagittal split was located just behind Spix's spine. Thus, more precise simulated osteotomies are needed to further validate the accuracy of virtual planning for this purpose.

Introduction The purpose of our study was to evaluate the benefit of bilateral inferior alveolar nerve block (BIANB) in managing postoperative pain, nausea and vomiting and opioid and antiemetic consumption in mandibular osteotomy. Material and methods 51 patients operated for bilateral sagittal split osteotomy (BSSO) were included in this prospective randomized controlled, double-blind, superiority trial. In the first group (n = 25), standard protocol was applied (general anesthesia and postoperative multimodal analgesia). The second group (n = 26) received bilateral inferior alveolar nerve block anesthesia at the start of surgery in addition to routine protocol. Postoperative monitoring was conducted every 4 h over the first 24 h and targeted the following criteria: postoperative nausea and vomiting (PONV), the visual analog scale (VAS) for pain, consumption of morphine (cumulative dose) and antiemetic agents, need for removal of guiding elastics. Results PONV was significantly lower in the BIANB group (15.4 % VS 40 %, p = 0.049), as were mean VAS scores for pain (1 VS 1.57, p = 0.045) and medians of morphine bolus (8 [6–16] VS 5.5 [1–8], p = 0.033). We found no significant difference in incidence of guiding elastic removal, and antiemetic consumption. Discussion The use of BIANB in BSSO improved postoperative patient comfort in terms of PONV and pain. Furthermore, it led to a decrease in opioid consumption. In conclusion, it is an additional therapeutic means of improving patients' postoperative comfort.

Unilateral posterior vertical insufficiency (PVI) is a growth defect of the mandibular condyle that results in a facial asymmetry. Various surgical procedures can be used to elongate the hypoplastic ramus. The aim of this study was to evaluate long-term aesthetic and architectural outcomes of vertical ramus osteotomy (VRO) in patients with unilateral PVI.Patients operated on with unilateral VRO were included in this retrospective study. Aesthetic and architectural parameters were evaluated on frontal photographs as well as on frontal and lateral cephalograms preoperatively, postoperatively, at 1-year and at the end of the follow-up.A total of 48 patients were analyzed. The aesthetic assessment revealed significant correction of the chin deviation (CD) and of the lip commissural line tilt after VRO (p1 = 0.0038 and p2 = 0.0067, respectively) with stable results. The architectural analysis revealed significant improvement in the maxillary and mandibular occlusal planes, as well as the chin deviation (p 0.0001). A tendency to relapse was noted for the mandibular canting and the CD during the follow-up. VRO allowed for a mean mandibular lengthening of 8.39 mm (ranging from 2.5 to 14 mm).VRO allows for immediate restoration of the symmetry of the lower third of the face in patients with unilateral PVI. A revisional procedure may be needed due to a tendency for the chin deviation to relapse.

The aim of this study was to compare the accuracy of two different voxel resolutions for the preoperative assessment of mandibular osteotomies. The study was conducted on 37 dry adult human mandibles. To obtain measurement standardization, heated gutta-percha cones were placed on the dry mandibles to mark 20 anatomical points. These cones were used for all measurement groups. Cone beam computerized tomography (CBCT) scans of the mandibles were made using 0.200 mm3 and 0.400 mm3 voxel sizes (Planmeca Promex-3D Helsinki, Finland). The results obtained from these two groups were compared with physical measurements obtained using a digital calliper, in order to analyze their predictive value. In the study, one voxel size did not have supremacy over the other in terms of accuracy. For mandibular osteotomies, 0.400 mm3 voxel size can be preferred because of lower radiation dose.

The various abnormalities of occlusion cause significant discomfort to the patient suffering from them. Currently, the surgical treatment of malocclusion in healthy patients is a routine process. The situation is completely different when the patient has a serious disease of the respiratory or cardiovascular system - a condition which may contraindicate such treatment. A 30-year-old female patient, with a class III skeletal defect (open bite and progeny) and Eisenmenger's syndrome was chosen as a clinical case. The DDS-Pro software was selected to plan the operation. The bilateral sagittal split osteotomy of the mandible was selected as the method of surgery. At the time of the initial examination, the patient had been denied surgical treatment several times in several other clinics. Before the treatment began, the patient underwent intensive preparation in the cardiac surgery unit for 2.5 months. Using the software, a surgical intervention was planned with the production of a surgical template. The operation was then performed; the treatment period was unremarkable. The resulting occlusion and changes in the shape of the face fully met the patient's psychological and esthetic expectations. In conclusion, a complicated cardiovascular pathology does not always deprive patients with malocclusion of the possibility to undergo surgical treatment.

Background Currently, botulinum toxin A (BTA) is mainly used in the treatment of muscle spasms and in cosmetic procedures, and its cosmetic indications are expanding rapidly. There have been sporadic reports focused on the preoperative usage of BTA complementing plastic surgery. We briefly summarize the current experience of BTA complementing plastic surgery in China based on clinical experience. Methods We reported a brief review of the preoperative use of BTA as an accessory to plastic surgery (blepharoplasty, chin augmentation, mandibular angle ostectomy, rhinoplasty, hyaluronic acid fillers injection for wrinkle reduction) based on previous studies and our experience. Results Preoperative treatment with BTA in plastic surgery helps surgeons operate and results in better cosmetic results. Conclusions Preoperative BTA treatment can reduce the occurrence of surgical complications as well as improve the surgical results in some plastic surgeries. The procedure is suitable for clinical application and worth promoting.

Objective: Patient safety and low complication rates are indispensable in surgical training and models are among the main educational tools. The aim of this study is to assess the efficiency of a novel model for orthognathic mandibular osteotomy. Material and Methods: A template and seventeen partial mandibular models (MM-17) were manufactured with air dried clay. The dimensions of the models were feasible for sagittal split ramus osteotomy (SSRO). Model surgery was performed by surgeons with a minimum of three years’ experience in orthognathic surgery. Each surgeon operated four separate models and the following data were recorded: corticotomy and SSRO completion time, MM-17 fracture type, similarity value of MM-17 with native mandible, representation value of MM-17, and the training compatibility value of MM-17. Results: The cost was 0.6 American Dollars. The mean corticotomy time was 126.75 seconds (110-150). Mean cortical resistance similarity value was 8.75 (8-10). The mean SSRO time was 288 seconds (205-401). Sixty percent of the fractures were seen in the outer cortex. The mean medullary resistance similarity value was 5 (4-6) and mean mandibular representation value was 5.25 (4-7). The training compatibility value was 8.25 (7-10). Conclusion: Air dried clay demonstrated mechanical similarities with bone cortex and it was used for mandibular modelling for the first time. MM-17 cost less than other devices. Corticotomy and SSRO completion times were short due to the lack of dissection and bleeding. Despite its drawbacks in SSRO, MM-17 is a versatile and low cost alternative in orthognathic mandibular corticotomy training. High power drill utilization skills may be gained with MM-17 before clinical practice.

In this article, we describe 2 high-stake diagnostic pitfalls that occurred in a single patient having undergone partial glossectomy and marginal mandibulectomy for invasive squamous cell carcinoma. Margins were grossly uninvolved. Histopathology showed a moderately differentiated squamous cell carcinoma. Microscopic evaluation of margins was challenging, as the inferior osseous margin submitted en face showed spongiotic epithelium with mixed chronic and acute inflammation, representing a periapical cyst after correlation with the gross examination. Another section of the osseous margin showed a small non-atypical epithelial nest, consistent with an odontogenic epithelial rest. We wish to raise awareness of these diagnostic pitfalls as a bone margin with such epithelial foci could be misinterpreted as positive, with serious therapeutic consequences.

Reduction mandibuloplasty is one of the most frequently performed aesthetic surgical procedures in Korea. Cases of facial nerve injury after mandibuloplasty have been reported, but most of those cases have not been clearly presented in detail. This report describes the case of a 38-year-old patient who underwent reduction mandibuloplasty at a local plastic surgery clinic. A massive bleeding event occurred during surgery, and hemostasis was performed by a surgeon at the local clinic. During an exploratory procedure, we found that the facial nerve trunk was clipped with a metallic hemoclip. We then straightened the pressed epineurium to its original shape under surgical microscopy. Oral prednisolone administration began on the first day after the procedure and was gradually tapered off. The patient showed some improvement after 7 weeks and showed 80% to 90% improvement after 5 months.

With the development of computer-assisted surgery, preoperational design is detailed in software. However, it is still a challenge for surgeons to realize the surgical plan in the craniofacial surgery. Robot-assisted surgery has advantages of high accuracy and stability. It is suitable for the high-stress procedures like drilling, milling, and cutting. This study aims to verify the feasibility for automatic drilling without soft tissues in model test based on an industrial robot platform.This study chose the data from digital laboratory in Shanghai 9th People's Hospital. The mandibular was reconstructed in software and surgical plan was also designed. Then, the coordinate data was input to the robot's software and matrix conversion was calculated by 4 marked points. The trajectory generation was calculated by inverse kinematics for target coordinates and robot coordinates. The model was fixed and calibrated for automatic drilling. At last, the accuracy was calculated by optic scanning instrument.The installment and preparation cost 10 minutes, the drilling procedure cost 12 minutes. The outside position error was (1.71 ± 0.16) mm, the inside position error was (1.37 ± 0.28) mm, the orientation error was (3.04 ± 1.02)°. Additionally, a total of 5 beagles were tested, with an accuracy error of (2.78 ± 1.52) mm. No postoperative complications occurred.This is the first study reported for robot-assisted automatic surgery in craniofacial surgery. The result shows it is possible to realize the automatic drilling procedure under the condition of no interference like soft tissues. With the development of artificial intelligence and machine vision, robot-assisted surgery may help surgeons to fulfill more automatic procedures for craniofacial surgery.

Two-month-old (Case 1) and one-year-old (Case 2) Japanese Black cattle presented with bilateral rostral mandibular open fractures. At presentation, the proximal edges of each fracture were discolored and had a severe stench, indicating necrosis caused by infection. In both cases, a bilateral rostral mandibulectomy over the symphysis was performed. Although the tongues of both animals prolapsed post-surgery, they had no significant problems with eating or drinking. Case 1 showed excellent growth during fattening, and Case 2 successfully became pregnant and gave birth. Rostral mandibulectomy can be an effective surgical option for the treatment of cattle with difficulty in internal or external fixation due to unfavorable necrotic cranial mandibular open fractures.

Segmental defect areas in the mandible can change immediately following osteotomy due to muscular traction, impacting on accurate reconstruction. The purpose of this article is to introduce a new technique based on virtual surgery planning to record the position of the bony parts prior to mandibulectomy, for use in precise mandibular reconstruction after segmental osteotomy. The position information for the bony parts is transferred to a plate with complementary surface contact and locating holes with specific directions and angles. This technique was performed for six patients with segmental defects and the results were compared to those of six previous patients in whom the technique was not utilized. The design of the location holes shortened the average operation time from 406 minutes to 349 minutes (P = 0.033) and decreased the average, maximum, and minimum graft deviation from 1.21 mm to 0.88 mm (P = 0.015), 1.28 mm to 0.99 mm (P = 0.027), and −1.15 mm to −0.77 mm (P = 0.077), respectively. The design of the locating holes in multiple plates shortened the time taken for the bony repositioning step and hence significantly shortened the total operation time. More importantly, it also increased the reconstructive accuracy.

The aim of this study was to evaluate the impact of extubation time on postoperative complications in patients undergoing bimaxillary orthognathic surgery. We therefore retrospectively compared the effect of early extubating (EE) in the operating room versus delayed extubating (LE) on the intensive care unit (ICU) regarding postoperative complications and length of ICU/hospital stay (LOICUS/LOHS). Furthermore, we analyzed the influence of the PAS change on postoperative complications.The clinical data of 117 patients were retrospective analyzed regarding postoperative complications using Clavian-Dindo Classification. Volumetric calculations of the pre- and postoperative PAS were conducted using ITK-SNAP software. The Fisher's exact test was performed to evaluate the significance of differences between categorical variables. Continuous variables were analyzed using the Mann-Whitney U-Test or the Kruskal-Wallis one-way analysis of variance. Regression analysis was used estimating predictors for postoperative complications.EE led to significant shortening of LOICUS (p 0.001) and LOHS (p = 0.023). In total, we recorded 38 complications (minor n = 30; major n = 8) within the hospital stay. Complication rates were without significant differences with respect to the postoperative ventilation strategy. Large changes in PAS volume led to an increase in the major complication rates (p = 0.031). Increase or decrease of PAS was independent from postoperative complication rates (p = 1.000). Higher body mass index (p = 0.04) and a higher ASA PS score (p = 0.016) were associated with increased major complication rates.Early extubation after surgery is a safe procedure and is associated with a reduced LOICUS and LOHS. Complications seem to occur more frequently in marked changes of the PAS and should be considered in perioperative risk stratification.

The aim of the study was to analyze the anatomic location differences of the mandibular lingula (ML) between dentoskeletal Class I and Class III patients, also between genders to obtain information that could be useful for sagittal split ramus osteotomy (SSRO) and other interventions in mandibular ramus.This study was conducted on cone-beam computed tomography (CBCT) images of 30 skeletal Class I (16 males and 14 females) patients aged between 18 to 37 years and 30 skeletal Class III (14 males and 16 females) patients aged 18 to 36 years.Statistically, the mean distance of the ML from the occlusal plane in skeletal Class III patients (9.91±3.16mm) was found to be greater than Class I patients (8.12±2.95mm). The mean distance between the posterior border of ramus and the ML was found to be statistically lower (15.82±1.80mm) compared to Class I patients (16.55±1.67mm) but the mean distance from the anterior ramus was not found statistically significant. In both groups, the mean distance between the ML and posterior ramus was statistically greater in males. The mean distance from mandibular notch to ML was significantly greater in Class III patients (18.73±2.89mm) compared to Class I patients (17.70±2.65mm) (P0.05). The most commonly encountered shape was the nodular type in both groups. The second most common type was truncated in Class I patients and triangular in Class III patients.The ML is an important landmark for mandibular ramus surgery and inferior alveolar nerve block (IANB). The anatomic data provided by this study may help surgeons to reduce complications when performing mandibular ramus osteotomies and dentists to increase the success rates of IANB.

Background In carefully selected oral cavity cancers, marginal mandibulectomy is an adequate procedure which achieves good disease control adhering to the principle of “doing as little as possible and as much as necessary”. Methodology This was a retrospective study done by reviewing the medical records of all patients who underwent marginal mandibulectomy for resection of oral cavity cancers in our institution during a period of 5 years. Data was collected from medical case records and analyzed. Results 125 cases underwent marginal mandibulectomy for resection of oral cavity cancers. 88.5% of advanced oral cavity cancers that underwent neoadjuvant chemotherapy followed by marginal mandibulectomy are still disease free. The local recurrence rate was 10.4%. Among cases which recurred, 61.5% were in T2 stage of the disease and 30.8% recurred in buccal mucosa. For lesions on the mandible (26/125), the final histopathology showed bone infiltration in only 12% cases and among them only one recurred. Among 88/125 cases where the lesion was abutting mandible even after stretching mucosa, recurrence was noted only in 11.4% with 3-year overall survival of 79.3%. Conclusions The low recurrence rate following marginal mandibulectomy in our study shows good locoregional control when performed for a lesion close to or abutting alveolar periosteum. In management of advanced oral cavity cancers, neoadjuvant chemotherapy followed by marginal mandibulectomy was effective in achieving significant locoregional control. For superficial lesions on the mandible, marginal mandibulectomy gives adequate margin clearance resulting in long term survival.

The use of individually designed osteotomies, combined with individually manufactured osteosynthesis material, is rapidly becoming a standard for more challenging maxillofacial surgery. The benefits of patient-specific implants (PSI) in orthognathic surgery are clear in complex cases. PSIs can enhance precision and ease up the surgical protocol. We previously reported on the benefits of PSIs as reposition and fixation systems during Le Fort I osteotomy. The aim of this study was to evaluate a cohort of 28 patients, treated with bilateral sagittal split osteotomy (BSSO) and PSIs for fixation, with regard to healing for up to 3 years. A retrospective cohort of 48 patients with conventional mini-plate repositioned mandibles was also collected for statistical analysis. No statistically significant differences were found with regard to infection, soft tissue problems, or reoperations between these two groups. (C) 2018 European Association for Cranio-Maxillo-Facial Surgery. (C) Published by Elsevier Ltd. All rights reserved.

Objective The aim of this study was to compare the accuracy of simulated mandibular osteotomies performed with cutting guides and two different intraoperative navigation systems based on simple (sAR) and navigated (nAR) augmented reality technology. Material and methods A total of 126 osteotomies were performed on 21 identical mandible models according to a prespecified virtual surgery plan. The data from postoperative computed tomography (CT) images were fused with preoperative CT scans to objectively compare the outcomes, i.e. angular deviations from the osteotomy trajectory (°) and displacement of two control points (mm). Results Osteotomies performed with cutting guides turned out to be the most accurate, with mean angular deviation of 4.94 ± 4.62° and mean control point displacement of 1.65 ± 0.88 mm. Mandibular osteotomies assisted with sAR and nAR were less accurate in terms of mean angular deviations (5.34 ± 3.67° and 7.14 ± 5.19°, respectively) and control point displacements (1.79 ± 0.94 mm and 2.41 ± 1.34 mm, respectively). Conclusion Our findings imply that in future, AR-based intraoperative navigation systems may find application in everyday clinical practice. Although AR technology still requires some improvements, it can already be used for presentation of digital navigation data, enhancing surgeon's awareness and hand-eye coordination during mandibular resection and reconstruction procedures.

Surgical treatment of facial asymmetry usually involves 2-jaw orthognathic surgery. But when the size of the mandible differs a great deal between the right and left sides, as in hemimandibular hyperplasia, additional contouring surgery is required. A 20-year-old woman presented with facial asymmetry, showing marked mandibular hyperplasia of the right side. She was treated with the use of 2-jaw surgery with mandibular body osteotomy in conjunction with orthodontic intrusion. Good esthetic outcome and functional occlusion were achieved.

Strong mandibular angles and a heavy chin are perceived as masculine features, so surgical feminization of female or transgender faces may warrant mandibular base narrowing (borders and angles) and a reduction in chin width and height. With this in mind, we have devised an interdental midline osteotomy (triangular in shape and with a caudal base) to accompany a box-shaped impaction osteotomy of the chin symphysis and horizontal triangular resection of the lateral mandibular border. The reduction of the intergonial width and of the mandibular border and chin widths takes place upon closure of the midline defect. Between November 2016 and August 2017, five patients agreed to the mandibular feminization osteotomy and were followed up thereafter for 6-13 months. All expressed satisfaction with the results; no dental, periodontal, or temporomandibular joint-related complications were encountered. This technique is a viable alternative to buccal decortication, chin reduction osteotomy, and masseter reduction surgery.

BACKGROUND Microvascular reconstruction is the standard of care in head and neck reconstruction, though its perioperative safety in an older population has been controversial due to safety concerns, warranting further investigation. MATERIALS AND METHODS An "older" (≥71 years) cohort undergoing reconstruction after mandibulectomy/glossectomy was compared to the remaining population in a National Surgical Quality Improvement Program (2008-2016) analysis. Cases required both a mandibulectomy/glossectomy and microvascular or local flap reconstruction (exclusion criteria: missing ages and simultaneous microvascular and local flap reconstruction). Demographics, comorbidities, and procedure types were analyzed on 985 patients (236 [24.4%] were ≥71). Outcomes were compared by reconstruction type. Regressions were performed calculating the impact of age on length of hospital stay (LOHS) and operative time. RESULTS Ablative procedures were comparable, but older patients received local flaps at higher rates (22.5% vs. 9.6%; p

Objectives Osteoradionecrosis (ORN) of the mandible is a common complication of head and neck radiotherapy and often requires surgical treatment. Squamous cell carcinoma (SCC) can be exceptionally discovered within zones of ORN on histological examination of the operative specimen. The authors discuss the management of these lesions based on a short patient series. Materials and methods This single-centre retrospective study was based on patients managed between 2012 and 2014 for ORN with incidental discovery of microscopic SCC. Results Five patients with incidental discovery of microscopic SCC in a zone of ORN of the mandible were included in this study. The mean time to onset of ORN after the end of radiotherapy for locally advanced SCC of the oral cavity or oropharynx was 42 months. Surgical treatment consisted of marginal or segmental mandibulectomy with free flap reconstruction. No recurrence was observed with a mean follow-up of 35 months [24–46]. Conclusion The incidental discovery of microscopic SCC in a zone of ORN of the mandible is a rare event and has not been reported in the literature. Optimal management cannot be reliably defined due to the lack of data in the literature, but the present study supports careful histological examination of ORN specimens. Treatment must be as conservative as possible to avoid excessively invasive surgery.

The structure and dimensions of the mandible, tongue, and hyoid complex are important variables in the pathophysiology of obstructive sleep apnea at the hypopharyngeal level. Genioglossus advancement is based on mandibular osteotomy, which brings the genioglossus muscle (GGM) forward and prevents posterior collapse during sleep. The genioglossus advancement technique has recently undergone several modifications; each has attempted to minimize surgical morbidity while improving the incorporation and advancement of the GGM. The hyoid bone has been of interest in sleep apnea and apnea-related surgical procedures because of its integral relationship with the tongue base and hypopharynx. Hyothyroidopexy is illustrated.

Summary Purpose Class II dento-facial deformity due to inferior alveolar retrusion may be difficult to treat using conventional surgical procedures. The aim of this study was to report on total mandibular subapical osteotomy (TMSO) to correct inferior alveolar retrusion, to describe its indications, the surgical technique and to analyse the aesthetic, occlusal changes and stability. Materials and methods Patients treated with TMSO from January 2004 to December 2014 were included and analysed retrospectively. Delaire's cephalometric analysis was performed before surgery and one year after surgery. Skeletal, occlusal and soft tissue changes were measured comparing lateral cephalographs before and after surgery. Results From January 2004 to December 2014, 8 patients were treated by TMSO. Six patients were analysed and presented a stable class I occlusion 3 years after surgery with an improvement of the labio-mental sulcus. Mean position of the dental apex of the inferior central incisor (ia) before surgery was −8.5 mm corresponding on an inferior alveolar retrusion of −8.5 mm. After surgery, mean ia position was −0.25 mm showing an average of alveolar advancement of 8.25 mm. Regarding the soft tissues movements, the mean labio-mental angle showed a variation from 84.7° to 120.3°, and the deepest point of the labio-mental sulcus (Mli) was advanced with a mean of 9.22 mm corresponding to the bone movements. Conclusion Total mandibular subapical osteotomy may be considered as a stable, safe and ideal procedure for patients having a class II deformity, due to a total inferior alveolar retrusion without mandibular retrognathism, improving labio-mental sulcus and chin shape.

The Chin Wing is a modified genioplasty extended along the basilar border and the angles of the mandible. This technique may be a better choice than standard genioplasty for correction of lip incompetence, retrogenia and high angle position associated with hyperdivergent cases. Our objective was to analyse the overall movement realized during surgery and the long-term stability of this procedure. Ten patients underwent a Chin Wing surgery from June 2018 to August 2019. All patients were operated on by the same surgeon. We performed a preoperative (PO), an immediate postoperative (POI), and an over 6 months postoperative (PO6) Cone Beam Computed Tomography (CBCT) for every patient. 3D reconstructions were performed for each CBCT with Proplan software. We were thus able to determine by subtractions acquired and resorbed bone volume. Some section plans were chosen in order to perform 2D measurements. The CBCT volume comparisons reveal a gain of 7.6cc between the PO and the POI, for a bone resorption of 2.5cc between POI and PO6 (33% of the volume gained). In 2D evaluation, we observe an average resorption of 1.7 mm corresponding to approximately 20% of the height gained, at the level of the mandibular angle. Given the low bone resorption we can consider Chin Wing stable over time. The important quantity of mobilized bone and the basilar rotational movement may explain over-standing aesthetic and functional outcome, compared to classical genioplasty.

Purpose. This study explored the effects of genioplasty (Gep) and anterior subapical osteotomy of the maxilla and mandible (ASOMx+ASOMd) on the pharyngeal airway dimensions of patients with bimaxillary protrusion (BiP). Method. Thirty-two patients were divided into 2 groups. Group 1 received ASOMx+ASOMd, and group 2 received ASOMx+ASOMd+Gep. The cephalograms of the patients were collected before surgery and 2 months after surgery. Changes in the landmarks, related cephalometric angles (gonial, SN-GoGn, Y -axis, and SN-C2C4 angles), and 2 pharyngeal airway dimensions (uvulo-pharyngeal airway [UOP] and tongue–pharyngeal airway [TOP]) were analyzed. Results. Before surgery, the parameters (incisor superius, incisor inferius, menton, most superior and anterior point of the hyoid bone, tip of the uvula, inferoanterior point on the second cervical vertebra, and inferoanterior point on the fourth cervical vertebra) and measured angles (SNA, SNB, ANB, gonial, SN-GoGn, Y -axis, and C4C2-SN) of both groups showed no significant differences. Following ASOMx, the patients in groups 1 and 2 exhibited a setback by 7.0 and 6.6 mm, respectively. After ASOMd, groups 1 and 2 exhibited 4.9 and 5.3 mm setbacks, respectively. No significant difference in the amount of setback was observed between groups 1 and 2. The postoperative horizontal and vertical positions of Me in group 2 were significantly forward by 6.1 mm and upward by 1.5 mm, respectively. Regarding pharyngeal airway dimensions, TOP was decreased in group 1 (1.7 mm) and group 2 (1.3 mm). In the postoperative Pearson correlation coefficient test, the horizontal and vertical positions of Me showed no significant correlation with TOP in both groups. Therefore, Gep did not prevent the reduction of TOP in group 2. Conclusion. After bimaxillary anterior subapical osteotomy, the TOP of patients with BiP was decreased, and this situation was unavoidable, regardless of whether Gep was performed.

Extra-oral vertical ramus osteotomy (EVRO) is used in orthognathic surgery for the treatment of mandibular deformities. Originally, EVRO required post-operative inter-maxillary fixation (IMF). EVRO has been developed by the use of rigid fixation, omitting no post-operative IMF. We examined retrospectively the long-term stability and post-operative complications for patients with mandibular deformities who underwent EVRO with internal rigid fixation. Patients who were treated with EVRO for a mandibular deformity in the period 2008–2017 at Clinic of Oral and Maxillofacial Surgery, Molndal, Sweden were included (N = 26). Overjet and overbite were calculated digitally and cephalometric analyses were performed pre-operatively, and at 3 days, 6 months, and 18 months post-operatively. There was a general setback of the mandible, decreased gonial angle and reduced degree of skeletal opening. Excellent dental and vertical skeletal stabilities were seen up to 18 months post-operatively, although a relapse was seen sagitally up to 6 months post-operatively. Since the overjet did not show any significant change over time, the sagittal skeletal changes are attributed to dental compensation. There was no permanent damage to the facial nerve and 5.8% neuro-sensory damage to the inferior alveolar nerve was observed.

Purpose Operative management has been reported to show varying degrees of therapeutic effects for non-bacterial diffuse sclerosing osteomyelitis of the mandible (DSOM). The purpose of this study was to retrospectively analyze and summarize the operative outcomes for non-bacterial DSOM. Methods In this retrospective cohort study, patients with non-bacterial DSOM who received operative treatment were enrolled at the Peking University Hospital of Stomatology between 2012 and 2019. The primary predictor variables were the type of operative treatment and number of operations. The outcome variables were operative outcomes (symptom relief or ineffective) and time to recurrent symptoms after operations. Other study variables were demographics, including sex, age, and non-bacterial DSOM onset time. The χ2 test and Kaplan–Meier model were used to evaluate differences. Results The sample was composed of 72 patients with a mean age at onset of 26.1 ± 17.8 years and showed a female predilection. Decortication was performed for 68 patients with non-bacterial DSOM, and 4 patients underwent segmental mandibulectomy. Symptom relief was achieved in 37 (54.4%) patients after the first decortication, and the median time to symptom recurrence was 2.0 months. Furthermore, the longest time to symptom recurrence was not more than 6 months in all patients. Among the 4 patients who underwent segmental mandibulectomy, 2 who received fibula repair experienced recurrence of symptoms at 4 and 5 months after the operations, respectively, and their normal mandible and the transplanted fibula also presented with imaging manifestations of osteomyelitis. Conclusions Decortication and segmental mandibulectomy were not effective for non-bacterial DSOM. This finding is consistent with the results of other reports, and this condition may be best managed non-operatively by rheumatologists.

BackgroundThe 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.Methods107 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.ResultsThe 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%, pConclusionBilateral 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 numberNCT02618993.

Although some technical modifications were made since H.L. Obwegeser introduced the combined maxilla and mandibular osteotomy techniques for orthognathic surgery in 1960s, the fundamental concepts of H.L. Obwegeser did not seem like changed [1]. The sequence of the orthognathic surgery varies according to the preference of the surgeons. Personally, I prefer the maxilla-first approach for patients with Class III deformities and facial asymmetry while I mostly do the mandible-first approach in patients with Class II deformities. I am convinced that the orthognathic surgical procedures could be executed effectively without complication if the surgeon was aware of the surgical anatomy and basic concept of this technique. This chapter addresses the details of the personal preferences and modifications in orthognathic surgical techniques including the surgical anatomy.

Purpose This study sought to geometrically evaluate the effect of a mandibular prosthesis on facial asymmetry in patients with one of two different types of mandibulectomy defect. Methods Facial data from 20 participants (9 men and 11 women; mean age 68 years) with either a reconstructed segmental defect (segmental group,n = 10) or a marginal mandibulectomy defect (marginal group, n =10) were acquired with a non-contact three-dimensional (3D) digitizer. Facial asymmetry was evaluated by superimposing a facial scan onto its mirror scan using 3D evaluation software. Facial scans with and without the mandibular prosthesis in place were also superimposed to evaluate the effect of the mandibular prosthesis. Results Facial asymmetry differed significantly between subjects with and without the prosthesis in the segmental group (P = 0.005) but not in the marginal group (P = 0.16). There was no significant difference in the effect of the prosthesis on facial appearance between the two groups (P = 0.052). The ratio of 3D deviation of facial asymmetry without the prosthesis and in the mirror scan with the prosthesis differed significantly between the two groups (P = 0.01). Conclusions Placement of a mandibular prosthesis has a notable effect on facial asymmetry in patients with segmental mandibulectomy defects.

Background Despite reports demonstrating feasibility of immediate dental implant placement in mandibular reconstruction with free fibula flaps for benign disease, this practice is not routinely used in the oncologic setting. The authors aim to demonstrate the safety of immediate dental implant placement for oncologic mandible reconstruction. Methods In 2017, the authors' center began immediate dental implant placement in free fibula flaps for oncologic patients undergoing mandibulectomy reconstruction. Immediate dental implant placement patients were compared to a historical cohort also reconstructed with computer-aided design and manufacturing technology beginning in 2011 (n = 34) as a noninferiority study design. Primary outcomes of interest included 90-day complications, time to radiotherapy, and time to and number of patients achieving dental restoration. Results Sixty-one patients underwent free fibula flaps following mandibulectomy using computer-aided design and manufacturing. Seventy-two dental implants were placed in the immediate dental implant placement cohort (n = 27). No differences were noted in major or minor 90-day complications between groups (p > 0.05). Radiotherapy was required in 55 percent in the immediate dental implant placement cohort versus 62 percent in the historical cohort, with no significant difference in time to radiotherapy (67.6 days versus 62.2 days, respectively). One dental implant was removed for nonosseointegration noted during vestibuloplasty. Fourteen (51.8 percent) immediate dental implant patients had complete dental restoration at 90 days compared with none in the historical cohort (p Conclusions Immediate dental implant placement is a safe procedure with an unchanged short-term complication profile and no delay in radiotherapy initiation. Patients undergoing immediate dental implant placement are more likely to complete full dental rehabilitation. Long-term and health-related quality-of-life outcomes remain to be determined. Clinical question/level of evidence Therapeutic, III.

The involvement of temporalis muscle fibers by oral submucous fibrosis (OSMF) and the procedure of coronoidectomy and temporalis myotomy in the surgical treatment protocol for the disease is a controversy. The primary objective of this study is to evaluate the histopathological changes in temporalis muscle fibers in patients undergoing surgical treatment for OSMF and to authenticate the importance of temporalis myotomy and coronoidectomy in surgical treatment protocol. A 3-year prospective study was conducted to assess the histopathological changes in temporalis muscle in surgically treated OSMF cases. The predictor variables were drawn from demographic characteristics (age and gender) etiology, and mouth opening. The outcome variables were histopathological assessment of temporalis muscle fibers for parameters suggestive of degenerative changes and fibrosis changes at cellular level. Out of 56 patients, 30 patients were had surgical intervention. Twenty-eight (93.3%) were male and 2 (6.6%) were female with a ratio of 14:1. Histopathological examination of temporalis muscle fibers revealed hyalinization of muscle fibers in 80% of the patients followed by loss of striation (73.33%), fragmentation (60%), nucleus internalization (33.33%), infiltration of macrophages and other inflammatory cells (20.67%), multiple nuclei (20%), and swollen muscle fibers (6.67%). Mean preoperative mouth opening was 12.4 and post-operatively 41.3 mm on 1-year follow-up and this was stable on further follow-up. The results of this study suggest involvement of temporalis muscle with disease itself and the justification for coronoidectomy and temporalis myotomy in the surgical protocol was established.

INTRODUCTION Peripheral nerves transmit nerve signals between periphery and the spinal cord or brain stem. Its function can be compromised by trauma to the nerve, such as those that occur in surgical procedures such as orthognathic surgery. Depending on the type of injury, treatment may be proposed, but this is still a controversial point in literature. Alternative methods that assist in the treatment of paresthesia should be studied, and in this context, selegiline hydrochloride seems to be a promising drug. AIM Based on the above, the aim of this study was to evaluate the effectiveness of selegiline hydrochloride in the treatment of facial sensory changes resulting from nerve injuries in patients undergoing maxillary orthognathic surgery. METHODS This was a double-blind randomized clinical trial with the voluntary participation of individuals who underwent orthognathic surgery. The facial sensitivity of these patients was evaluated by 2-point discrimination tests and directional perception in the region related to the lower alveolar nerve. Tests were comparatively applied at times T0 (before surgery), T8 (8 days after surgery), T15 (15 days after surgery), T30 (30 days after surgery), T60 (60 days after surgery), and T90 (90 days after surgery). RESULTS The mean age of patients was 31.14 years. With the comparative analysis of the 2-point static test on the chin, difference was observed between groups at times T15 (P = 0.007), T30 (P = 0.010), and T90 (P = 0.027) in the intergroup evaluation. Regarding results of the comparative analysis of the 2-point static test on the lip, difference was observed between groups at times T30 (P = 0.023), T60 (P < 0.001), and T90 (P = 0.005) in the intergroup evaluation. In the direction test on the chin, difference was observed between groups at times T30 (P = 0.015), T60 (P = 0.001), and T90 (P < 0.001) in the intergroup evaluation. CONCLUSIONS Selegiline hydrochloride has shown promising results in the treatment of neurosensory disorders resulting from maxillary orthognathic surgery.

Odontogenic myxoma (OM) are benign, locally aggressive tumours that are rarely found in the paediatric maxillofacial region. OMs derive from mesenchymal odontogenic tissue. We describe the management of a 3-year-old girl who presented with a large right-sided mandibular lesion. Her treatment included conservative excision, curettage and peripheral ostectomy. A literature review was performed which calls into question the dogmatic practice of resection with 1 to 1.5 cm margins. Treatment approaches to the OM could potentially be altered in the paediatric patient.

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OBJECTIVES/HYPOTHESIS While nonunion after mandibular reconstruction for head and neck surgery is rare, literature exploring management is scarce. Our primary objective was to determine success rates of tibial bone graft (TBG) in achieving mandibular union. Secondary objectives include determining factors that contribute to failure of TBG. STUDY DESIGN Retrospective Chart Review. METHODS Retrospective chart review between January 1, 2008 and December 31, 2018. Patients who underwent a mandibulotomy or mandibulectomy with osteocutaneous free flap reconstruction were identified. Patients who were pursuing dental rehabilitation, subsequently diagnosed with mandibular nonunion and received a cancellous TBG were assessed. RESULTS The 15 patients meeting inclusion criteria were mostly male (67%), white (87%), and nonsmokers (67%) with a median age of 64 (IQR = 60-73). Successful union occurred in 13 of 18 (72%) TBGs and the majority (63%) had a partial union documented at the time of surgery. Five patients (83%) who initially had a mandibulotomy achieved union compared to 78% of those with osteocutaneous reconstruction (P = 1.0). Postoperative radiation did not affect rates of union: 80% for both (P = 1.0). Patients with osteoradionecrosis (ORN) achieved union in 67% of cases compared to 75% of cases who did not have ORN (P = .86). There were similar rates of union for those who required perioperative antibiotics for infection and those without infection (67% vs. 75%, P = .86). Dental rehabilitation was achieved in 55% of patients, most commonly dentures. CONCLUSIONS This study shows that TBG can be used to achieve union for patients with malunion after head and neck cancer reconstruction. We show its successful use within the reconstructive algorithm for patients regardless of postoperative radiation for very small defects. LEVEL OF EVIDENCE 3 Laryngoscope, 131:1291-1296, 2021.

Summary Objectives The accelerated tooth movement phenomenon after orthognathic surgery has been observed. However, the underlying mechanism remains unclear. There is no experimental study showing the effect of orthognathic surgery on orthodontic tooth movement of the opposing jaw. Therefore, the present study aimed at investigating if mandibular osteotomy enhances maxillary tooth movement and bone remodelling. Materials and methods Fifty-four male Sprague-Dawley rats were randomly divided into two groups: maxillary tooth movement (TM) and maxillary tooth movement + mandibular surgery (TM + MS). The orthodontic force was delivered to move the left maxillary first molar mesially. The surgical intervention was performed on the left mandible. Microcomputed tomography, histological analysis, enzyme-linked immunosorbent assay, and quantitative real-time polymerase chain reaction were used to assess changes at 3, 7, and 21 days after surgery. Results The mandibular osteotomy accelerates the rate of maxillary tooth movement with decreased bone volume fraction on the seventh day. Bone resorption was observed on the third and seventh day after mandibular osteotomy. It was found that serum interleukin-1β level increased significantly in the TM + MS group compared with the TM group, as well as the high expression level of cathepsin K and tumour necrosis factor receptor-associated factor 5 of the orthodontic tooth on the third and seventh day after mandibular osteotomy. Conclusion Data from the present study suggested that mandibular osteotomy accelerates maxillary osteoclast activity and post-operative tooth movement, providing evidence for accelerated tooth movement phenomenon after orthognathic surgery.