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This article describes a novel minimally invasive technique for bilateral sagittal split osteotomy (BSSO) that aims to reduce surgical trauma while maintaining bone overlap and rigid internal fixation for proper consolidation of the bone segments. The technique involves a small vestibular mucoperiosteal incision made on the lateral aspect of the mandible between the first and second molars, enabling a standard ramus split, surgical segment movement, and miniplate fixation. A retrospective evaluation of 67 consecutive patients who underwent BSSO using this protocol showed favorable split of the mandible with no unfavorable splits or non-union. Patients were discharged from hospital within an average of 17 h with minimal postoperative complications. This technique provides good surgical visualization with a very small incision and allows standard BSSO surgery without difficulty. [ABSTRACT FROM AUTHOR]

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

This retrospective study examined long-term (4–5 years) condylar positional and volumetric changes and skeletal stability after bimaxillary orthognathic surgery in skeletal Class III patients. Pre-surgical (T0: 0.9 ± 1.1 months) and post-surgical (T1: 0.6 ± 0.7 months; T2: 12.8 ± 3.1 months; T3: 56.5 ± 6.5 months) cone beam computed tomography (CBCT) images of 22 patients were obtained. CBCT multiplanar reformation (MPR) images were generated, and three-dimensional (3D) condylar models were constructed and superimposed to compare changes in condylar volume from pre- to postoperative. Condylar position in the sagittal and coronal planes altered immediately after surgery; however at long-term follow-up, the condyles had returned to their pre-surgical position. The condyles remained slightly inwardly rotated at short-term (−2.6°, 95% confidence interval −3.5° to −1.7°) and long-term (−1.9°, 95% confidence interval −2.8° to −1.0°) follow-up. Changes in condylar volume were insignificant after surgery. Condylar positional changes had no effect on skeletal stability. However, patients with an increased face height prior to surgery and more retrusive jaw position postoperatively were more prone to condylar resorption. Surgical changes remained stable 4–5 years after surgery. In conclusion, condylar position changed insignificantly following surgical correction in Class III patients provided that the correct surgical technique was employed. [ABSTRACT FROM AUTHOR]

BackgroundThe lingula is an important landmark for conducting certain mandibular surgery procedures, such as sagittal split ramus osteotomy (SSRO) and intraoral vertical ramus osteotomy (IVRO). The purpose of this study was to investigate the location of the lingula in both horizontal and vertical planes among four different shapes of the mandibular ramus.MethodsNinety patients, 60 female and 30 male, underwent cone beam computed tomography scans to evaluate the measurements of the lingula tip (Li) in relation to the anterior border (AB), posterior border (PB), sigmoid notch (SN), and inferior border (IB) of the ramus. The proportional relationship of the Li in both the horizontal and vertical planes is indicated by the Li–AB/AB–PB ratio and Li–SN/SN–IB. lingula shapes were categorized into triangular, truncated, nodular, and assimilated shapes. Statistical analyses were performed to compare the variations in the measurements between different shapes of lingula and genders.ResultsThe mean Li–AB distance was 18.88 mm, and it was determined to be significantly greater with the truncated shape when compared to the other three shapes. The mean Li–PB distance was 15.23 mm, with no significant differences observed among the four shapes. The mean Li–AB/AB–PB ratio was found to be 55.3%. The truncated shape had a ratio of 57.2%, which was significantly higher compared to the nodular shape (54%) and assimilated shape (50.4%). The mean distance was 19.95 mm for the Li–SN and 31.34 mm for the Li–IB. There was no significant difference in these distances among the 4 lingula shapes. The mean Li–SN/SN–IB ratio was 38.5%. There were no significant differences in measurements between male and female.ConclusionSignificant differences were observed in the 4 lingula shapes in relation to the Li position, which was situated superiorly and posteriorly to the central point of the ramus. Therefore, it is crucial to take into account the differences in lingula shapes during SSRO and IVRO procedures on the ramus.

The purpose of this study was to elucidate the effects of mandibular anatomy and osteotomy technique on lingual fracture patterns in SSRO. The predictor variables were: length of horizontal medial osteotomy; type of border osteotomy; buccolingual width; and vertical length of the basal cortex. The outcome variable was the type of lingual split pattern. This was categorized into four types according to a lingual split scale (LSS): LSS 1, true Hunsuck; LSS 2, fracture line to posterior border of the ramus; LSS 3, through to mandibular canal; LSS 4, unfavorable fracture pattern. Data were analyzed using analysis of variance and the Pearson χ2 test. Values of p < 0.05 were considered statistically significant. The study sample comprised 312 lingual split patterns in 156 patients. The most common type of lingual split pattern was LSS 1 (n = 204). There was a significant relationship between inferior border osteotomy type and LSS type (p = 0.001). Whilst LSS 1 was the most common among all border osteotomy types. LSS 4 was most frequently observed in cases where the lower border osteotomy remained in the buccal surface. According to the results of this study, the likelihood of an unfavorable split pattern increases when the lower border osteotomy remains in the buccal surface. [ABSTRACT FROM AUTHOR]

Objective: The objective of this study was to evaluate the effect of orthognathic surgery on taste sensation. Materials and methods: Thirty-five patients scheduled to undergo Le Fort I osteotomy (LFIO), sagittal split ramus osteotomy (SSRO), and bimaxillary surgery (BMS) were evaluated by administering localized and whole-mouth taste tests preoperatively and postoperatively at months 1, 3, and 6. The patients were asked to identify the quality of four basic tastes applied to six locations on the palate and tongue and to rate the taste intensities they perceived. Taste recognition thresholds and taste intesity scores were evaluted according to operation groups and follow-ups. Results: There were significant decreases in the quinine HCl recognition thresholds at the postoperative follow-ups compared to the preoperative in LFIO patients (p = 0.043). There were significant decreases in sucrose taste intensity scores in the right posterolateral part of the tongue at months 3 and 6 compared to preoperative in SSRO patients (p = 0.046), and significant increases in quinine HCL taste intensity scores in the right and left anterior parts of the tongue at month 6 compared to preoperative in LFIO patients (p < 0.05). Conclusion: Taste perception is affected due to potential damage to the chemosensory nerves during orthognathic surgical procedures. Generally, non-significant alterations have been observed in taste perception after orthognathic surgery, except for significant alterations in bitter and sweet taste perceptions. Clinical relevance: Maxillofacial surgeons should be aware of taste perception change after orthognathic surgery procedures and patients should be informed accordingly. The trial registration number (TRN): NCT06103422/Date of registration: 10.17.2023 (retrospectively registered). [ABSTRACT FROM AUTHOR]

Key Clinical Message: Sturge–Weber syndrome (SWS) is a neurocutaneous syndrome characterized by angiomas. This report presents airway management using submental intubation in sagittal split ramus osteotomy under general anesthesia and aimed to explore better anesthetic management for avoiding the rupture of angiomas in a patient with SWS. [ABSTRACT FROM AUTHOR]

Objective: Unilateral temporomandibular joint ankylosis with jaw deformity (UTMJAJD) may require simultaneous total joint prosthesis (TJP) reconstruction, sagittal split ramus (SSRO), and Le Fort I osteotomies. The purpose of this study was to evaluate outcomes in patients treated with these procedures. Methods: Patients diagnosed UTMJAJD between 2016 and 2018 were selected for the study. Mandible-first procedure was performed after ankylosis release with TJP on the ankylosed side and SSRO on the contralateral side. Le Fort I osteotomy with and without genioplasty was lastly performed. Maximal incisor opening (MIO), facial symmetry, and jaw and condyle stability were compared before, after operation, and during follow-ups. Results: Seven patients were included in the study. Their average chin deviation was 9.5 ± 4.2 mm, and maxillary cant was 5.1 ± 3.0°. After operation, jaw deformity significantly improved, with chin deviation corrected 7.6 ± 4.1 mm (p = 0.015) and advanced 5.9 ± 2.5 mm (p = 0.006). After an average follow-up of 26.6 ± 17.1 months, MIO significantly increased from 11.4 ± 9.3 to 35.7 ± 2.6 mm (p = 0.000). The occlusion was stable with no significant positional or rotational changes of the jaw (p > 0.05). There was no obvious condylar resorption during follow-ups. Conclusion: Simultaneous TJP reconstruction, SSRO, and Le Fort I osteotomy are reliable and effective methods for the treatment of UTMJAJD. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to assess the correlation between temporomandibular joint (TMJ) disc position and skeletal stability and identify the cephalometric measurements associated with relapse after bimaxillary surgery. Methods: The participants were 62 women with jaw deformities (124 joints) who underwent bimaxillary surgery. The TMJ disc position was classified into four types (anterior disc displacement (ADD), anterior, fully covered, and posterior) using magnetic resonance imaging, and cephalometric analysis was performed preoperatively and 1 week and 1 year postoperatively. The differences between pre- and 1-week postoperative values (T1) and 1-week and 1-year postoperative value (T2) were calculated for all cephalometric measurements. Moreover, the relationship between skeletal stability using cephalometric measurements, skeletal class, and TMJ disc position was analyzed. Results: The participants included 28 patients in class II and 34 in class III. There was a significant difference in T2 in SNB between class II mandibular advancement cases and class III mandibular setback cases (P = 0.0001). In T2, in ramus inclination, there was a significant difference between the ADD and posterior types (P = 0.0371). Stepwise regression analysis revealed that T2 was significantly correlated with T1 for all measurements. However, the TMJ classification was not applied to all measurements. Conclusion: This study suggested that TMJ disc position, including ADD, could not affect skeletal stability, including the maxilla and distal segment after bimaxillary osteotomy, and short-term relapse could be related to the movement amount or angle change by surgery for all measurements. [ABSTRACT FROM AUTHOR]

Purpose: The anatomical position of the lingula is clinically very important to prevent injuries during sagittal split ramus osteotomy. Our study aims to evaluate the localisation of the lingula by cone beam computed tomography (CBCT) and to compare the localisation of the lingula between malocclusion, gender, and lingula types. Methods: A retrospective study was conducted to evaluate the shape and location of the lingula using CBCT. A total of 250 CBCT images were included in this study. The lingula was classified as nodular, assimilated, truncated, or triangular type. Six defined distances from the top of the lingula were measured: anterior border of the ramus (L-A), posterior border of the ramus (L-P), internal oblique ridge (L-IOR), mandibular notch (L-N), and distal surface of the mandibular second molar (L-M2) and occlusal plane (L-OP). The measured distances were compared between gender, malocclusion, and lingula types. Results: The most common type of lingula was nodular (32.4%). The L-N, L-P, L-M2, and L-OP distances between genders were statistically higher in male patients than in female patients. The L-IOR, L-M2, and L-OP distances exhibited statistically significant differences found between malocclusions. No statistically significant difference was found when the distances of the lingula to the anatomical points were compared between the lingula types. Conclusion: These variations in positioning of the lingula depending on the dysmorphoses are developing towards a systematic 3D examination before any mandibular osteotomy to precisely visualize the position and shape of the lingula. [ABSTRACT FROM AUTHOR]

Summary: This study evaluated the stability of bilateral sagittal split ramus osteotomy (BSSRO) associated with positional plagiocephaly and temporal and masseter muscles using posteroanterior cephalogram analysis and three-dimensional computed tomography (3D-CT). This retrospective cohort study included 31 patients who underwent BSSRO for mandibular asymmetry. The cranial vault asymmetry index (CVAI) and the cephalic index were used as indicators of positional plagiocephaly. The distance from the vertical reference line to the menton (Me) was measured on posteroanterior cephalograms immediately and 1 year after surgery, and postoperative stability was assessed. Temporal and masseter muscles were constructed from 3D-CT data and their volumes were measured. Simple regression analysis showed a significant correlation between postoperative changes in the vertical reference line to the Me and the CVAI (R = 0.56, p = 0.001), the amount of surgical movement in the vertical reference line to the Me (R = 0.41, p = 0.023), and the variable temporal muscle volume (R = 0.27, p = 0.028). There was no significant correlation between postoperative changes in the vertical reference line to the Me and the cephalic index (R = 0.093, p = 0.62) and variable masseter muscle volume (R = 0.16, p = 0.38). According to multivariate analysis, CVAI (p = 0.003) and amount of surgical movement in the vertical reference line to the Me (p = 0.014) were significant predictors of postoperative change in the vertical reference line to the Me. Positional plagiocephaly and amount of surgical movement influence lateral skeletal stability following BSSRO for mandibular asymmetry.

Objective: The purpose of this study is to assess the impact of Sagittal Split Ramus Osteotomy (SSRO) on the alignment of the condyle and orientation of the Ramal segment following surgery in patients operated for the correction of mandibular asymmetry. Methods: A total of 27 patients who underwent SSRO were enrolled in this study, and study groups were defined as asymmetric (study group) and symmetric (control group) using linear measurements from the dental midline based on a three-dimensional coordinate system. Differences on preoperative and postoperative values of anterior (AJS), posterior (PJS) and superior joint spaces (SJS), condylar axial angle (CAA), Sagittal Ramal Angle (SRA), and Coronal Ramal Angles (CRA) of study and control groups were measured and compared. The data was analyzed using the “Wilcoxon signed-ranks test” to identify differences between groups. Results: Differences between preoperative and postoperative values of CRA and SRA of the contralateral group showed statistically significant results with p-values of 0.007 and 0.005, respectively. A statistically significant change in CAA angle was found in the control and deviation groups (p = 0.018 and p = 0.010, respectively). Conclusions: SSRO has inevitable effects on the condylar and ramal orientation. Individuals with asymmetry require particular attention throughout the planning process and beyond. Conjunctive modalities and modifications should be considered and utilized when necessary. Future studies with larger sample sizes, homogenous follow-up periods, and more comprehensive clinical data are needed to substantiate understanding of the response of the condylar segment. Clinical relevance: Orthognathic surgeries inevitably alter the alignment and harmony of temporomandibular structures and may result in change of AJS, PJS, SJS, CAA, SRA, and LRA, which may change the biomechanics of joint and lead to several complications like temporomandibular disorders. Especially in cases with midline asymmetry needs special consideration from planning till the end of the treatment to achieve best results. In severe cases, conjunctive modalities and modifications and other alternatives such as inverted-L osteotomies should be considered. [ABSTRACT FROM AUTHOR]

The aim of this study was to identify clinical factors associated with progressive facial swelling after orthognathic surgery. Patients diagnosed with jaw deformities and undergoing orthognathic surgery were retrospectively evaluated, and those with surgical site infection, Le Fort I osteotomy, or genioplasty only were excluded. Facial swelling volume was calculated by comparing facial volume preoperatively and three days postoperatively using 3D images and image analysis software (VECTRA H2). FXIII was measured within three days after surgery in only patients with unexplained postoperative bleeding or hematoma. The correlation between facial swelling volume and clinical factors was statistically analyzed. Facial swelling volume was examined in 78 patients. Univariate analysis showed a significant difference between facial swelling volume (mean = 41.6 cm3) and operation time (mean = 209.3 min, r = 0.283, p = 0.012), ΔHb level (mean = 1.18 g/dL, r = 0.235, p = 0.039), as well as decreased factor XIII activity (mean = 75.3%, p = 0.012). Multivariate analysis showed a significant difference between facial swelling volume and FXIII deficiency (standard error = 6.44, p = 0.031).Progressive facial swelling immediately after orthognathic surgery may be due to factor XIII deficiency. [ABSTRACT FROM AUTHOR]

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

Resumen: Actualmente, los procedimientos mínimamente invasivos son una tendencia en todos los campos de la medicina, donde la cirugía mínimamente invasiva se define como la disciplina en la que las intervenciones quirúrgicas se realizan de formas novedosas para disminuir las secuelas de las disecciones quirúrgicas estándar. Los objetivos de la cirugía mínimamente invasiva son reducir el trauma tisular, minimizar el sangrado, el edema y las lesiones a los tejidos adyacentes, mejorando así la velocidad y la calidad de la recuperación.Varios artículos publicados recientemente han aplicado este concepto a la cirugía ortognática, donde los resultados avalan que los pacientes sometidos a este tipo intervenciones mediante incisiones pequeñas y disecciones mínimas tienen menor morbilidad y una recuperación postquirúrgica más rápida.El siguiente artículo tiene como objetivo realizar una revisión de la literatura y exponer las técnicas mínimamente invasivas en lo que respecta a la osteotomía Le Fort I, osteotomía sagital de rama mandibular y genioplastía. Abstract: Currently, minimally invasive procedures are a trend in all medical fields, where minimally invasive surgery is defined as the discipline in which surgical interventions are performed in novel ways to decrease the sequelae of standard surgical dissections. The goal of minimally invasive surgery is to reduce tissue trauma, minimize bleeding, edema, and injury to adjacent tissues, thereby improving the speed and quality of recovery.Recently, several articles have applied this concept to orthognathic surgery, where the results support that patients undergoing this type of procedure, through small incisions and minimal dissections, have less morbidity and faster post-surgical recovery.The following article aims to review the literature and expose the minimally invasive techniques related to Le Fort I osteotomy, sagittal split ramus osteotomy and genioplasty.

Segmental mandibular advancement (SMA) consists of a combination of bilateral sagittal split osteotomy, anterior subapical osteotomy with extraction of the first premolars, and genioplasty, to allow an extended advancement of the mandible for the improvement of tongue base obstruction in moderate-to-severe obstructive sleep apnoea (OSA) and to minimize any unfavourable aesthetic change due to the large jaw advancement. The aim of this pilot study was to evaluate the surgical outcomes and complications following SMA in OSA patients. Twelve patients (nine male, three female) underwent SMA as part or whole of their skeletal advancement procedure for OSA. The apnoea–hypopnoea index (AHI) improved from a mean± standard deviation 42.4 ± 22.0/hour preoperatively to 9.0 ± 17.4/hour at 1 year postoperative. Surgical success (50% reduction in AHI) was achieved in 11 of the 12 patients (91.7%) at 1 year postoperative, while seven patients (58.3%) attained surgical cure (AHI<5/hour). The lowest oxygen saturation (LSAT) increased from a mean 73.3% preoperatively to 78.7% at 1 year postoperative. The airway volume increased from a mean 2.4 ± 1.7 cm3 at baseline to 6.7 ± 3.5 cm3 at 1 year postoperative (P < 0.001). No major complication occurred. This pilot study showed that SMA appears to be safe and effective as part or whole of the skeletal advancement surgery for moderate-to-severe OSA. [ABSTRACT FROM AUTHOR]

The purpose of the present study was to compare changes in the stability of the pharyngeal airway space (PAS) and the hyoid bone position between patients with and without mandibular asymmetry. We included 104 patients who underwent sagittal split ramus osteotomy. Patients whose menton was deviated by ≥ 4 mm from the facial median line were categorized as the asymmetry group. The patients were divided into the symmetry group (72 patients) and the asymmetry group (32 patients). The patients treated were evaluated using lateral cephalometric radiography 1 and 6 months postoperatively. Following orthognathic surgery, the airway space in the oropharynx and the hypopharynx significantly decreased in both the both groups (p < 0.05). The diameters of the oropharynx and hypopharynx in the asymmetry group gradually decreased after sagittal split ramus osteotomy compared with those in the symmetry group (p < 0.05). The hyoid bone was moved in an inferoposterior direction postoperatively in both groups. In the symmetry group, the hyoid bone that was moved inferiorly tended to move back toward the original position over a period of 6 months postoperatively(p < 0.05). In the asymmetry group, the hyoid bone that was moved inferiorly remained in the same position 6 months postoperatively. These results showed that the time required before pharyngeal airway morphology and the hyoid bone were stabilized was relatively longer in the asymmetry group. [ABSTRACT FROM AUTHOR]

The purpose of this retrospective study was to analyze changes in the position of the condyles following mandibular setback surgery with manual guidance. The study included 28 patients with mandibular prognathism who underwent mandibular setback surgery using manual guidance with a bioabsorbable mesh for mandibular fixation, and changes in the position of the center of the condylar head were compared at three time points: before surgery (T0), within 1 week after surgery (T1), and 6 months after surgery (T2). The results showed significant lateral, anterior, and inferior movements of the condyle at T1 compared to T0, with an average movement of 0.66 ± 0.84 mm along the x-axis, −1.27 ± 0.82 mm along the y-axis, and −0.20 ± 0.69 mm along the z-axis, with a 1.77 ± 0.87 mm linear distance (p < 0.05). At T2, the condylar position had mainly changed inferiorly along the y-axis (−0.17 ± 0.48 mm) (p < 0.05) compared to that at T0. The change in the position along the x-axis (−0.14 ± 0.57 mm), z-axis (−0.05 ± 0.68 mm), and linear distance (0.85 ± 0.57 mm) at T2 was not significantly different from that in the condylar position at T0 (p > 0.05). The study suggests that significant anterior–lateral–inferior condylar movement occurs within 1 week after mandibular setback surgery using manual guidance, but the condyle returns to its original position over time, which is clinically acceptable. [ABSTRACT FROM AUTHOR]

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Copyright of Diyala Journal of Medicine is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: To investigate and compare the effect of two orthognathic procedures for mandibular setback, namely, sagittal split ramus osteotomy (SSRO) and intraoral vertical ramus osteotomy (IVRO), on oral health, mental- and physical health-related quality of life across time. Materials and methods: Patients with mandibular prognathism and planned for orthognathic surgery were recruited in this study. Patients were randomized into two groups (IVRO and SSRO groups). Quality of life (QoL) was assessed with the 14-item Short-Form Oral Health Impact Profile (OHIP-14) and the 36-item Short-Form Health Survey (SF-36) preoperatively (T0), postoperative 2 weeks (T1), 6 weeks (T2), 3 months (T3), 6 months (T4), 12 months (T5), and 24 months (T6). A comparison of OHIP-14 and SF-36 scores between two groups was conducted. Results: Ninety-eight patients (49 SSRO group, 49 IVRO group) participated in this study. There was no significant difference in OHIP-14 scores between SSRO and IVRO throughout the treatment process. SSRO group had significant reduction of OHIP-14 score (i.e., improving oral health–related QoL) since postoperative 2 weeks, whereas IVRO group had significant reduction since postoperative 6 weeks. Starting from postoperative 3 months, the oral health–related QoL of both groups was already significantly better than the baseline level and continued to steadily improve afterwards. For SF-36, both groups had increased physical health summary score starting from postoperative 2 weeks, indicating an early and gradual recovery of physical health–related QoL. The mental health summary score of the SSRO group began to increase from postoperative 2 weeks, but that of the IVRO group only began to increase from postoperative 6 weeks. Patient age at the time of surgery was positively correlated with OHIP scores in the postoperative period. Conclusions: The study concludes that both SSRO and IVRO contributed to the improvement of QoL in the long term, but oral health– and mental health–related QoL of SSRO groups showed earlier improvement. Clinical relevance: Undergoing orthognathic surgery at early ages is advised, as older age of patients appeared to have worse QoL. Trial registration: Clinical trial registration number: HKUCTR-1985. Date of Registration: 14 Apr 2015. [ABSTRACT FROM AUTHOR]

The sagittal split ramus osteotomy (SSRO) has been performed mainly on an inpatient basis because of the duration of anaesthesia and the potential risk of postoperative complications, such as bleeding, pain, nausea, and vomiting. However, advances in both surgical and anaesthetic management have enabled the reduction of these risks and shortened the length of hospital stay. Thus, the SSRO may be feasible even in the ambulatory setting in elective cases. The clinical records of all patients who underwent an outpatient SSRO between August 2011 and September 2020 at Lilla Craniofacial Clinic were reviewed retrospectively. Data on age, sex, duration of surgery, operative procedures, intraoperative bleeding, and admission status were investigated. In total, 143 patients underwent a bilateral SSRO. The SSRO was performed as an isolated procedure in 73 patients and concomitantly with other surgical procedures in the remaining 70 patients. Overall, 142 of the 143 patients were discharged on the day of surgery (99.3%); only one (0.7%) required an overnight stay because of a submental haemorrhage after genioplasty. No emergency hospitalizations or readmissions occurred after discharge. Multimodal perioperative management, both surgical and anaesthetic, facilitated enhanced patient recovery after surgery, and SSRO was performed successfully and safely as an ambulatory procedure. [ABSTRACT FROM AUTHOR]

Osteochondromas (OCs) are rare benign tumors of the temporomandibular joint (TMJ) area, while synovial chondoromatoses are rare benign tumor-like disease. Few reports on the simultaneous development of an OC and synovial chondromatosis have been published. We describe here an extremely rare case of facial asymmetry caused by an ipsilateral OC and synovial chondromatosis at the TMJ. A patient was referred to our department with a chief complaint of malocclusion. Cephalometric photographs showed facial morphological asymmetry, and computed tomography imaging revealed a left condylar head tumor and multiple calcified lesions in the superior joint space. A dentofacial deformity induced by a tumor at the left condylar head and synovial osteochondromatosis at the left TMJ was diagnosed. He initially underwent condylectomy and tumorectomy. Histopathologically, the mandibular surface was elevated and capped with cartilage that exhibited weak atypia and a low cell density. The bone beneath the cartilage cap was thickened, but no atypia was noted. In the second surgical step, bilateral sagittal split ramus osteotomy was performed to improve the facial appearance and achieve normal occlusion. Finally, three dental implants were inserted to replace missing teeth for oral rehabilitation. Three years have passed since the completion of all treatments, and the patient is progressing well without recurrence of the TMJ tumor or mandibular deviation. Mandibular movement is normal, and the final occlusion and facial appearance remain satisfactory. [ABSTRACT FROM AUTHOR]

The patterns of the lingula and antilingula are crucial surgical reference points for ramus osteotomy. Cone-beam computed tomography (CBCT) provides three-dimensional images, and patient radiation dose is significantly lower for CBCT than for medical CT. The morphology of the mandibular lingula and antilingula of ninety patients (180 sides) were investigated using CBCT. The lingula were classified as having triangular, truncated, nodular, and assimilated shapes. The antilingula were classified as having hill, ridge, plateau, and plain shapes. The patients' sex, skeletal patterns (Classes I, II, and III), and right and left sides were recorded. The most to least common lingula shapes were nodular (37.8%), followed by truncated (32.8%), triangular (24.4%), and assimilated (5%). The most to least common antilingulae were hill (62.8%), plain (18.9%), plateau (13.9%), and ridge (4.4%) patterns, respectively. The lingula and antilingula had identical patterns on both sides in 47 (52.2%) and 46 patients (51.1%), respectively. Sex and skeletal pattern were not significantly correlated to lingula and antilingula shapes. No significant correlation was observed between lingula and antilingula shapes. [ABSTRACT FROM AUTHOR]

Objective To establish a three-dimensional coordinate system that can accurately measure the recurrence rate after orthognathic surgery, and evaluate and analyze the degree of recurrence. Methods Data from patients who underwent orthognathic surgery in a hospital were selected to reconstruct three-dimensional images with spiral CT. The two researchers used the multiplane assisted positioning method to fix the points three times and screened them using intra-andintreclass correlation coefficients (ICC). Reproducible and accurate landmark points were drawn to establish different coordinate systems and calculate the facial asymmetry index (AI) to determine the coordinate system with the best mid-sagittal plane symmetry. This coordinate system and lateral radiographs were used to separately measure the recurrence rate, and evaluate and analyze the three-dimensional recurrence degree of orthognathic surgery. Results Ten landmark points that may be repeatedly fixed were obtained, including N (nasion), K (K point), ANS(anterior nasal spine), PNS (posterior nasal spine), Ptm(pterygomaxillary fissure), Gn (gnathion), IZ(IZ point), MZ (MZ point), Ms (mastoideale), Cor (coronion) and and Go (gonion). Three coordinate systems were established, and the most suitable coordinate system was the upper edge point of the left infraorbital foramen. The inner upper edge of the right infraorbital foramen and both sides of the midpoint of the ear points constituted the horizontal plane (HP), which passed through the outermost point of the left zygomatic frontal suture and the outermost point of the right zygomatic frontal suture and was perpendicular to the horizontal plane to constitute the coronal plane (CP). It was perpendicular to the two planes to form a sagittal plane (SP). Two-dimensional and three-dimensional measurements of recurrence were performed on 112 patients, and new three-dimensional recurrence evaluation results were obtained. Less than 40% had low recurrence, 40% to 61% had moderate recurrence, and greater than 61% had high recurrence. Conclusion This study established a three-dimensional coordinate system suitable for measuring the recurrence rate after orthognathic surgery, obtained a new three-dimensional recurrence evaluation result, and provided a clinical experimental basis for evaluating the effect of orthognathic surgery and improving stability.

Background: Unfavorable fractures are among the most common complications of bilateral sagittal split ramus osteotomy (BSSRO). This study aimed to evaluate unfavorable fracture patterns during BSSRO and assess the related risk factors and treatment measures. Methods: The clinical records and radiographs of 679 patients (1 358 sides) who underwent BSSRO at Shanghai Ninth People’s Hospital between September 2013 and December 2021 were examined. Results: Patients with unfavorable fractures who underwent surgical restoration were studied. The incidence of unfavorable fractures was 0.8% (n=11), with the highest rate in the third year. The unfavorable fractures were divided into three types by location and clinical treatment: (1) SSRO could still be completed after buccal/lingual plate unfavorable fracture (0.6%, n=8); (2) condylar/coronoid process fractures/intermaxillary fixation needed (0.1%, n=2); (3) additional osteotomy required (0.07%, n=1). Conclusion: These results suggest that as a surgeon’s experience increases, the rate of unfavorable fractures may decrease. The novel classification of unfavorable fractures for SSRO might be useful for surgeons to make appropriate treatment choices during orthognathic surgery.

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This study aimed to investigate the changes in preexisting temporomandibular joint (TMJ) clicking and the new incidence of TMJ clicking after orthognathic surgery. A total of 60 patients (30 men and 30 women) with mandibular prognathism underwent intraoral vertical ramus osteotomy (IVRO) for a mandibular setback. The setback amount and TMJ clicking symptoms (preoperative and one year postoperative) were recorded. To assess the risk of new incidence of TMJ clicking in asymptomatic patients, the cutoff value for postoperative mandibular setback was set at 8 mm. The left and right mandibular setbacks were 11.1 and 10.9 mm in men, respectively, and 10.7 and 10.0 mm in women, respectively. Thus, no difference in setback amount on either side was observed between the sexes. The improvement rate in patients with preexisting TMJ clicking was 69.2% (18 of 26 sides); the postoperative improvement rates were 71.4% (setback amount > 8 mm) and 60% (setback amount ≤ 8 mm). IVRO may reduce the severity of preexisting TMJ clicking. A high setback amount (>8 mm) may not be associated with a considerable increase in the risk of postoperative TMJ clicking. [ABSTRACT FROM AUTHOR]

Purpose: This study compared the mechanical behavior of two fixation techniques used in three sections representing the sagittal split ramus osteotomy (SSRO) in polyurethane replicas that were divided into groups, according to type of section, and sub-groups according to type of fixation, simulating 11-mm advancement and 6º clockwise mandibular rotation. Methods: Loads were applied in two regions, aiming at progressive application and consequent strength value, measured in kilogram-force in displacements of 1, 3, 5, and 7 mm, from the load application tip. Shapiro–Wilk test was performed, followed by two-way analysis of variance (ANOVA-2 way), and Bonferroni's multiple comparison. Results: The results showed no statistically significant difference in the type of section and type of fixation used when load was applied to the inter-incisor region. However, when load was applied to the first molar region, statistically significant difference was observed in 1-mm displacement, in which section described by Epker with two modifications showed greater strength, regardless of type of fixation used (p = 0.007). Conclusion: In the application of load in the inter-incisor region, there was no statistical difference between the type of osteotomy and the type of fixation used. When applying loads to molars, there was a difference for the type of osteotomy, where the Epker osteotomy with 2 modifications presented greater resistance, regardless of the type of fixation used. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the stress distribution and displacement values of six different miniplate systems in large mandibular advancement after sagittal split ramus osteotomy (SSRO) with finite element analysis (FEA). A three-dimensional model of a mandible was created and a 10 mm advancement SSRO was simulated. The model was fixed using a four-hole miniplate, a six-hole miniplate, a newly designed six-hole miniplate and their curved versions. Maximum principal stress values for bone, von Mises stress values for osteosynthesis materials, and the amount of displacement between segments were measured. The highest von Mises value was observed in the curved version of the newly designed six-hole miniplate; the lowest value was detected in the four-hole curved miniplate. The lowest value of maximum principal stress in the bone was found in the curved version of the novel design six-hole miniplate. The least displacements between segments were also recorded in the new design of straight miniplate; therefore, for large mandibular advancement surgery, this novel six-hole miniplate may be a promising option with positive biomechanical characteristics. [ABSTRACT FROM AUTHOR]

Objectives: This pilot study evaluated the relationship between inferior alveolar nerve location through computed tomography scan and intraoperative inferior alveolar nerve entrapment after bilateral sagittal split osteotomy. Material and Methods: Overall, 20 helicoidal computed tomography scans were evaluated in patients with facial deformities who underwent to bilateral sagittal split osteotomy (BSSO). The distance from the mandibular canal to the internal surface of the buccal and lingual cortical bone, mandibular thickness, bone density and proportion of medullary and cortical bone in 3 regions were evaluated. During the intraoperative period, the segment to which the nerve remained adhered after performing BSSO was analysed, and the data correlated. Results: The distance from the mandibular canal to the buccal cortical bone showed a mean of 2.6 mm when the inferior alveolar nerve was adhered to the distal segment and mean of 0.7 mm when the nerve was adhered to the proximal segment. The thickness was 11.2 mm and 9.8 mm when the nerve was adhered the distal the proximal segments respectively. Mandibular thickness, distance from the mandibular canal to the buccal and lingual cortical were statistically related to intraoperative nerve entrapment (P < 0.05). Conclusions: Narrow jaws and the distance from the mandibular canal to buccal cortical bone less than 2 mm increases the risk of the inferior alveolar nerve entrapment in bilateral sagittal split osteotomy.

The purpose of this retrospective study was to analyze changes in the position of the condyles following mandibular setback surgery with manual guidance. The study included 28 patients with mandibular prognathism who underwent mandibular setback surgery using manual guidance with a bioabsorbable mesh for mandibular fixation, and changes in the position of the center of the condylar head were compared at three time points: before surgery (T0), within 1 week after surgery (T1), and 6 months after surgery (T2). The results showed significant lateral, anterior, and inferior movements of the condyle at T1 compared to T0, with an average movement of 0.66 ± 0.84 mm along the x-axis, −1.27 ± 0.82 mm along the y-axis, and −0.20 ± 0.69 mm along the z-axis, with a 1.77 ± 0.87 mm linear distance (p < 0.05). At T2, the condylar position had mainly changed inferiorly along the y-axis (−0.17 ± 0.48 mm) (p < 0.05) compared to that at T0. The change in the position along the x-axis (−0.14 ± 0.57 mm), z-axis (−0.05 ± 0.68 mm), and linear distance (0.85 ± 0.57 mm) at T2 was not significantly different from that in the condylar position at T0 (p > 0.05). The study suggests that significant anterior–lateral–inferior condylar movement occurs within 1 week after mandibular setback surgery using manual guidance, but the condyle returns to its original position over time, which is clinically acceptable.

Objectives: This pilot study evaluated the relationship between inferior alveolar nerve location through computed tomography scan and intraoperative inferior alveolar nerve entrapment after bilateral sagittal split osteotomy. Material and Methods: Overall, 20 helicoidal computed tomography scans were evaluated in patients with facial deformities who underwent to bilateral sagittal split osteotomy (BSSO). The distance from the mandibular canal to the internal surface of the buccal and lingual cortical bone, mandibular thickness, bone density and proportion of medullary and cortical bone in 3 regions were evaluated. During the intraoperative period, the segment to which the nerve remained adhered after performing BSSO was analysed, and the data correlated. Results: The distance from the mandibular canal to the buccal cortical bone showed a mean of 2.6 mm when the inferior alveolar nerve was adhered to the distal segment and mean of 0.7 mm when the nerve was adhered to the proximal segment. The thickness was 11.2 mm and 9.8 mm when the nerve was adhered the distal the proximal segments respectively. Mandibular thickness, distance from the mandibular canal to the buccal and lingual cortical were statistically related to intraoperative nerve entrapment (P < 0.05). Conclusions: Narrow jaws and the distance from the mandibular canal to buccal cortical bone less than 2 mm increases the risk of the inferior alveolar nerve entrapment in bilateral sagittal split osteotomy. [ABSTRACT FROM AUTHOR]

Purpose: To summarize unfavorable fracture patterns during sagittal split ramus osteotomy (SSRO) and investigate the association with influencing factors. Materials and Methods: We conducted a retrospective analysis of 1007 patients with 2008 sides of SSRO and classified unfavorable fracture patterns into three types: fracture lines involving the sigmoid notch, condylar process, or coronoid process (Type A); fracture lines extending from the posterior border of the mandibular ramus to the mandibular body or the anterior border of the ramus (Type B); and unfavorable fractures located in the anterior horn of the proximal segment with free fragment (Type C). Logistic regression analysis was used to evaluate factors influencing unfavorable fracture patterns, including sex, age at the time of operation, class of occlusion, presence of the third molar, uni- or bi-maxillary surgery, and the distance from the mandibular canal to the buccal cortex. Results: The distance from the mandibular canal to the buccal cortex was significantly associated with unfavorable fracture patterns during SSRO. The presence of third molars was significantly associated with Type A fractures. The distance from the mandibular canal to the buccal cortex was significantly lower in Type B fractures. Conclusion: We found that the influencing factors for unfavorable fracture patterns varied. Clinicians should pay specific attention to patients with factors for each unfavorable fracture pattern during SSRO. Level of Evidence IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266. [ABSTRACT FROM AUTHOR]

Objective: The internal fixation has been purpose of study for many years, but there is still no consensus on the best method of fixation in relation to resistance for bilateral sagittal split ramus osteotomy (BSSO) using plates. Therefore, the aim of this study was to assess five different methods of osteosynthesis using resorbable and non-resorbable plates and screws in simulated sagittal split osteotomy (SSO) of the mandibular ramus. Materials and Methods: SSO was performed in 25 polyurethane synthetic mandibular replicas. The distal segments were moved forward 5 mm, and the specimens were grouped according to the fixation method: Inion resorbable plate, KLS resorbable plate, standard four-hole titanium miniplate (Medartis), two standard four-hole titanium miniplates (Medartis) and an adjustable titanium miniplate (Slider/Medartis). Mechanical evaluation was performed by applying compression loads to first molar using an Instron universal testing machine up to a 5 mm displacement of the segments. Resistance forces were obtained in Newtons (N), and statistical analysis was performed using the software R v. 3.5 with significance level of 0.05. Linear mixed models were used to compare the force required to move each type of plate. Results: The results showed that the resistance of SSO was better accomplished using two titanium miniplates and KLS resorbable plate showed the least resistance. However, both titanium and resorbable plates behaved similarly in small displacements, which are most commonly observed in BSSO postoperative time. Conclusion: It can be concluded that both resorbable and non-resorbable systems might offer suitable mechanical resistance in the procedures where there are no mechanical postoperative complications. [ABSTRACT FROM AUTHOR]

We compared the stability and stress analysis of four different fixation methods after sagittal split ramus osteotomy (SSRO) in mandibular models. In the first model (1P1B) we adapted a four-hole, 2.0 mm standard miniplate on the osteotomy line with one bicortical screw at the top. In the second (2P) we placed two four-hole 2.0 mm standard miniplates above and below the osteotomy line. In the third (3B), we applied three inverted L-shaped bicortical screws, and in the last (1RP1B) we used a four-hole miniplate with increased thickness on the osteotomy line with one bicortical screw at the top. A static vertical load of 200 Newtons (N) was then applied to each model from the occlusal of the first molar. The maximum and minimum principal stresses on the bone were observed more in the proximal segment close to the osteotomy line in all groups. Maximum von Mises stresses were 2705.21 Megapascals (MPa), 1633.56 MPa, 1121.4 MPa, and 1734.44 MPa for the 1P1B, 2P, 3B, and 1RP1B groups, respectively. Displacement values were 1.92 mm, 1.15 mm, 0.79 mm, and 1.42 mm for the 1P1B, 2P, 3B, and 1RP1B groups, respectively. The reinforced plate contributed to the stabilisation, but it was not as effective as three bicortical screws and a double plate. [ABSTRACT FROM AUTHOR]

The aim of this systematic review was to investigate whether the presence of third molars (3Ms) during sagittal split osteotomy of the mandible increases the risk of complications. Searches were conducted using MEDLINE via PubMed, LILACS, Cochrane Central, Scopus, DOSS, and SIGLE via OpenGrey up to December 2020. Fifteen articles were included for evaluation and 14 in the meta-analysis, with a total of 3909 patients and 7651 sagittal split osteotomies (670 complications). Inferior alveolar nerve (IAN) exposure in the proximal segment was the most frequent complication (n = 409), followed by bad splits (n = 151). Meta-analysis revealed no significant increase in the incidence of 3M-related IAN exposure (P = 0.45), post-surgical infections (P = 0.15), osteosynthesis material removal (P = 0.37), or bad splits (P = 0.23). The presence of 3Ms was associated with a reduced risk of nerve disorder (P = 0.05) and favoured bad splits in the lingual plate (P = 0.005). The quality of evidence was very low, mainly due to non-randomized study designs, high risk of bias, inconsistency, and imprecision. This systematic review suggests that the removal of 3Ms before sagittal mandibular osteotomy does not reduce the incidence of complications. Thus, we recommend future better-designed studies with rigorous methodologies and adjustments for confounding factors. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare the mechanical characteristics of five commonly used fixation methods for sagittal split osteotomy with a major advancement and counterclockwise rotation with a model that mimics the human mandible. Twenty-five virtually osteotomised and 3-dimensionally printed hemimandibles were fixed with an 8mm gap at the upper border and a 12mm gap at the lower border of the osteotomy. The following fixation methods were used: Group 1: a single miniplate, group 2: two miniplates, group 3: three bicortical screws in the upper border, group 4: three bicortical screws in an inverted L configuration, group 5: a single miniplate and a bicortical screw. A mechanical test using vertical linear loading at 1 mm/min velocity on a universal testing machine was carried out. The forces needed to displace the distal segment from 1-5 mm were recorded. The difference between groups was statistically significant for all displacement levels. Group 1 showed the minimum, group 5 showed the maximum resistance in almost all displacement values and there was a trend for higher to lower resistance values towards groups 5 to 1. Fixation methods that used one bicortical screw and a miniplate or three bicortical screws showed higher load resistance against displacement. [ABSTRACT FROM AUTHOR]

Sagittal split ramus osteotomy (SSRO) is a versatile orthognathic procedure for correcting mandibular deformities. Various complications can possibly occur when performing SSRO, and it can even cause serious adverse consequences because of the complexity of anatomy and operative procedures. The types of complications and their accompanying clinical manifestations are closely related to the choice of diagnosis and treatment strategies and clinical outcomes. To discuss the causes, prevention, and treatment measures of various common complications of SSRO, domestic orthog-nathic surgery experts prepared this consensus to increase the awareness of SSRO complications, thereby ensuring safe surgical procedure and good results. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate whether differences in the pattern of the lingual plate split in sagittal split ramus osteotomy (SSRO) affect the remodelling of the split site. Sixty-one patients with mandibular prognathism (122 sides) underwent SSRO. Computed tomography (CT) was performed at 1 week and 1 year after SSRO. Bone splits were classified according to the lingual split scale (LSS) and the lateral bone cut end (LBCE) by evaluating CT images at 1 week. The remodelling at the split sites was evaluated by superimposing the CT images obtained at 1 week and 1 year. Regarding the LSS pattern, significant differences were observed in the distance between anteroposterior ramus points (P = 0.033) and the ramus area in the axial image (P = 0.011). The LBCE pattern also showed a significant difference in the distance between anteroposterior ramus points (P = 0.043). In conclusion, the differences in the lingual plate split and ramus cut end of the SSRO influence the postoperative remodelling in the anteroposterior region of the split site. [ABSTRACT FROM AUTHOR]

Postoperative orthodontic treatment after orthognathic surgery is particularly affected by relapse of ≥2 mm. Patients who had undergone surgery were retrospectively reviewed, and factors contributing to relapse were investigated. The study subjects were 130 patients who underwent bilateral sagittal split ramus osteotomy between January 2016 and December 2017 in our hospital. Lateral cephalometric radiographs were taken preoperatively (T1), immediately postoperatively (T2), and 1 year postoperatively (T3), and the positions of the maxilla and mandible (SNA, SNB), mandibular changes due to surgery [Point B (X, Y), Argo-FH, mandibular plane], hyoid position (MP-H), head position (NSL/CVT, SN-C2C4), and airway space (SPAS, MAS, IAS) were measured. Postoperative changes (T2–T1) and postoperative stability (T3–T2) were assessed, the change in Point B (X) between T3 and T2 was calculated, and those patients in whom this change was <2 mm (Group S) were compared with those in whom it was ≥2 mm (Group R). An unpaired t -test (p < 0.05) was used for statistical analysis. Complete sets of radiographs were obtained for 42 patients. A comparison of T2–T1 between Group S (n = 33) and Group R (n = 9) found no significant difference in either SNB or Point B (X), but significant differences in MP-H, NSL/CVT, and SN-C2C4 (p < 0.05). These results showed that postoperative mandibular relapse of ≥2 mm occurred irrespective of the degree of mandibular setback, and it was more likely to occur when surgery had resulted in a greater change in hyoid position. [ABSTRACT FROM AUTHOR]

BackgroundMandibular sagittal split ramus osteotomy (SSRO) is a routine surgery to correct mandibular deformities, such as mandibular retrusion, protrusion, deficiency, and asymmetry. However, nonunion/malunion of the fragments and relapse caused by fixation failure after SSRO are major concerns. Rigid fixation to maintain postosteotomy segmental stabilization is critical for success. Additionally, understanding the biomechanical characteristics of different fixation methods in SSRO with large advancements is extremely important for clinical guidance. Therefore, the aim of the present study was to evaluate the biomechanical characteristics of different SSRO methods by finite element analysis.MethodsSSRO finite element models with 5-, 10-, 15-, and 20-mm advancements were developed. Seven fixation methods, namely, two types of bicortical screws, single miniplate, dual miniplates, grid plate, dual L-shaped plates, and hybrid fixation, were positioned into the SSRO models. Molar and incisal biomechanical loads were applied to all models to simulate bite forces. We then investigated the immediate postoperative stability from four aspects, namely, the stability of the distal osteotomy segment, osteotomy regional stability, stress distribution on the mandible, and implant stress performance.ResultsThe stability of the distal osteotomy segment and osteotomy region decreased when the advancement increased. All seven fixation methods displayed favorable biomechanical stability under minor advancement (5 mm). With large advancements, bicortical screws, dual miniplates, and grid plates provided better stability. The von Mises stress was concentrated around the screws close to the osteotomy region for the proximal segment for all fixation methods, and the von Mises stress on implants increased with larger advancements. With small advancements, five fixation methods endured tolerable maximum stresses of

Background/Purpose: The neurosensory disturbance is a common complication following sagittal split ramus osteotomy (SSRO) whereas the shortest buccal bone marrow (SBM) is an important risk factor. The present study aimed to investigate the relationship between the occurrence rates of SBM among three skeletal patterns. Methods: The cone-beam computed tomography (CBCT) images of 90 participants were divided into skeletal Class I, II, and III. There were six horizontal planes separated apart by a 2 mm interval; it started with plane 0 (original intact mandibular canal) to plane 5 which was 10 mm below. The data of SBM were divided into two groups (SBM ≥ 1 mm and SBM

The goal of this study was to determine whether a relationship exists between the amount of mandibular setback and the amount of airway dimensional changes. Records and cone beam computed tomography (CBCT) of patients who had undergone isolated bilateral sagittal split osteotomy setback between January 1, 2013 and March 16, 2020 at a single institution were reviewed retrospectively. The primary outcome variable was upper airway volume dimension change, and the predictor variable was the magnitude of mandibular setback as measured by six different methods. Thirty-one patients were included in the study, with a mean mandibular setback ranging from 1.41 mm to 6.11 mm. None of the predictor variables showed an association with oropharyngeal (P = 0.54) or hypopharyngeal (P = 0.33) volume. Stepwise regression analysis failed to show any significant relationships. Similarly, there was no statistically significant association between any of the predictor variables and oropharyngeal (P = 0.44) or hypopharyngeal (P = 0.74) minimum axial area. The results showed that no correlation exists between the magnitude of mandibular setback and the amount of static airway dimensional changes; therefore, it may not be possible to predict whether obstructive sleep apnea will develop following mild to moderate mandibular setback based upon CBCT measurements. [ABSTRACT FROM AUTHOR]

Neurosensory disturbance of the inferior alveolar nerve (IAN) is an adverse effect associated with sagittal split osteotomies (SSO). The purpose of this work was to evaluate neurosensory recovery of the IAN when SSOs were performed with piezoelectric (PZ) versus reciprocating (RP) saws. This was a prospective split-mouth study of patients undergoing bilateral SSO using a PZ saw on one side and an RP saw on the other. The primary outcome of interest was neurosensory recovery, as assessed using the functional sensory recovery (FSR) scale defined by the UK Medical Research Council. Descriptive, bivariate, and regression statistics were computed. Twenty patients (40 SSOs) with a mean age of 19.9 ± 3.2 years were included. The mean mandibular movement did not differ significantly (P = 0.50) between the PZ and RP groups. All patients achieved FSR within 1 year of surgery (range 34–249 days). The median time to FSR overall was comparable between the PZ and RP groups (94.5 days and 101.5 days, respectively; P = 0.20). However, at the time FSR was achieved, PZ SSO sites were more likely to have higher neurosensory scores when compared to RP SSO sites (hazard ratio 2.3, 95% confidence interval 1.1–4.9, P = 0.04). [ABSTRACT FROM AUTHOR]

Objective: The incidence of postoperative nausea and vomiting (PONV) after general anesthesia with total intravenous anesthesia (TIVA) was reported to be significantly lower than with volatile inhalational agents (13.3% vs 25%). However, no investigation of PONV risk factors associated with TIVA has ever been reported. This cross-sectional retrospective study aimed to investigate whether known risk factors influenced PONV in intubated general anesthetics utilizing TIVA for dental or oral and maxillofacial surgery.Methods: Subjects were 761 patients who underwent dental or oral and maxillofacial surgery under TIVA with propofol, fentanyl, and remifentanil. Univariate and multivariable logistic regression analyses were performed using PONV (within 24 hours) as the dependent variable and previously reported risk factors as independent variables.Results: Age (odds ratio [OR]: 1.020 per year decrease; 95% confidence interval [CI]: 1.0002-1.0418; P = .047) and female sex (OR: 2.73; 95% CI: 1.60-4.84; P < .001) were positively associated with PONV. Sagittal split ramus osteotomy (SSRO) (OR: 2.28; 95% CI: 1.21-4.33; P = .011) and bimaxillary osteotomy (OR: 5.69; 95% CI: 2.09-15.99; P < .001) were more likely to be associated with PONV than operations that were neither bimaxillary osteotomy nor SSRO. Late PONV (2-24 hours) had an ∼2.7 times higher incidence than early PONV (0-2 hours).Conclusion: These findings suggest further PONV countermeasures, aside from TIVA with propofol and prophylactic antiemetics for orthognathic surgeries especially bimaxillary osteotomy, are needed. [ABSTRACT FROM AUTHOR]