Bilateral Sagittal Split Osteotomy Research Articles

Management of A Bad Split Complication: A Systematic Review

Introduction: Bad split is one of the well-known intra-operative complications that occur during the bilateral sagittal split osteotomy (BSSO) procedure, which is a rehabilitation procedure for patients with mandibular deformities. The prevention of further post-surgery complications required sufficient management of bad split complications. Objective: This study aimed to analyze the management of bad split complications during a BSSO procedure. Methods: The literature review was conducted in the form of library research in the field of bad split complications' management by a BSSO based on the Preferred Reporting Items for Systematic Reviews (PRISMA). Related studies were found through using a manual search using Pubmed, ScienceDirect, Ebscohost, Scopus, Medline, Embase, and Web of Science, among other search engines. The inception of incorporation standards, the process of data extraction, and the determination of the risk of bias were carried out by the authors. The process of data screening was conducted by applying the inclusion and exclusion criteria. Results: This paper systematically reviewed seven related studies, four of which were case series and two of which were cross-sectional. The utilization of additional osteosynthetic plates was revealed throughout the extraction process as the most acquainted course of action to manage the bad split complications during the BSSO procedure. Conclusion: The osteosynthetic plate and miniplate application with bicortical or monocortical screws were exposed as the most used treatment for bad split complications.

Are condylar repositioning devices required in bilateral sagittal split osteotomies?

Bilateral Sagittal split osteotomy (BSSO) is used to correct malocclusion by mobilizing the mandible during orthognathic procedures surgically. Although the use of condylar positioning devices (CPDs) seems judicious, its effect on condylar position and relapse has not been studied in depth. A few of the limitations are the precision of such devices, along with the added amount of time to the procedure. The outcomes of the CPDs may lead to the paralysis of the muscles of mastication, malalignment of the bone segments, and deranged position of condyle due to the inadvertent force used to bring the jaws into occlusion. Thus, an effort was made to compare the merits and demerits of manual repositioning with those of CPDs.

Subjective analysis of sensitivity perception in patients submitted to orthognathic surgery

Bilateral sagittal split osteotomy is the best-established orthognathic surgical technique for mandibular dentofacial deformities correction. Some technique-related complications may occur, being paresthesia the most common. Objective: To subjectively evaluate postoperative sensitivity of individuals who underwent orthognathic surgery. Material and methods: A two-part questionnaire was answered by thirty subjects in different post-operative periods: 48 hours (T1), 7 days (T2), 14 days (T3), 30 days (T4), 60 days (T5) and 90 days (T6). Significance level was set at 0.05. Results: In part one, the Nature of Altered Sensation evaluation was performed in chin and lips. There was an improvement from T1 to T6 in regarding locations of the altered sensation (p < 0.001), moments of the altered sensation (p = 0.001), and in pain or other unpleasant sensation (p = 0.003). Other variables regarding the Nature of the Altered Sensation did not show statistically significance difference over time (p > 0.05). Regarding part two, functional impairment, it was noted that there was an improvement in T6 in relation to all variables (p < 0.05). There is a decrease in pain, lip bites, burning sensation and drooling sensation (p < 0.05). Also, there was a decrease in the difficulty for oral care. Conclusion: There is an improvement in the Nature of Altered Sensation as well as functional impairment over time.

A retrospective study of unfavorable fractures during sagittal split osteotomy: A single surgeon’s experience

BackgroundUnfavorable 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. MethodsThe 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. ResultsPatients 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). ConclusionThese 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.

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

to evaluate the efficacy of dual-purpose computer-generated splint in guiding the proximal and the distal segment in bilateral sagittal split osteotomy. It was a prospective case series study directed on 8 class III patients indicating the need of maxillary advancement and mandibular set back by bilateral sagittal split osteotomy. A CAD/CAM splint is generated to guide the distal segment to the stable maxilla and at the same time a grooved extension to engage the proximal segment ensuring the condyle in its planned position during fixation. The primary outcome was measured by calculating the difference between the pre- and post-operative condylar segment position. The present study included five female patient and three male patient with mean age of 28.4 ± 5.1years. The accuracy of the splint in positioning the mandibular proximal segment showed promising results ranging from 2.59 to 0.49. The dual-purpose splint introduced in this study showed satisfied results in maintaining the pre-operative condylar position while securing the distal segment in the desired plan.

Four-dimensional visualization of mandibular movement in the Class III patient before and after combined orthodontic and orthognathic treatment

To analyze the results of jaw motion before and after combined orthodontic and orthognathic surgical treatment in the Class III patient. A 33-year-old male with Class III malocclusion (ANB -2°, Wits -3 mm) was referred for facial deformity and malocclusion. After orthodontic preparation, a bimaxillary mandibular first orthognathic surgery was performed. After bilateral sagittal split osteotomy (BSSO) the lower jaw was shifted on the right for 3 mm right and was cw rotated for 4 mm. Le Fort I osteotomy with segmentation was performed to move the maxilla forward for 6 mm and cw rotate for 4 mm. Four-dimensional visualization of the mandibular movement was made using Planmeca 4D jaw motion system. The valuable quantitative data regarding lower jaw movement and measurement information were exported and analyzed. The maximum aperture during opening-closing movement differ before (38.7 mm) and after surgery (32.1 mm) for 6.6 mm. After surgery horizontal displacement in the maximum left lateral excursion increased by 7.6 mm and in the maximum right lateral side by 4.6 mm. Protrusion increased by 0.9 mm after surgery. Combined orthodontic and orthognathic treatment can improve soft tissue, skeletal, dental relationship, and functional results.

Comparison of two surgical techniques (HOO vs. BSSO) for mandibular osteotomies in orthognathic surgery—a 10-year retrospective study

PurposeTo retrospectively compare the high-angled sagittal split osteotomy (HOO) and the bilateral sagittal split osteotomy (BSSO) for the correction of skeletal dysgnathias regarding intra- and postoperative complications.MethodsThe electronic medical records of all patients treated with an orthognathic surgery at the Department for Oral, Maxillofacial and Facial Plastic Surgery, University Hospital Frankfurt, Germany, between the years 2009 and 2019 were retrospectively reviewed.ResultsTwo hundred ninety-one patients were included. The overall complication rates were 19.78% (BSSO) compared to 12.5% (HOO) (p = 0.14). Significant differences were found regarding the operation time (HOO < BSSO, p = 0.02), material failure (HOO > BSSO, p = 0.04), and early recurrence requiring revision surgery (HOO < BSSO, p = 0.002). The use of a ramus plate significantly reduced the risk of plate failure (2.8% < 13.6%, p = 0.05). More bad splits (p = 0.08) and early sensory disorders (p = 0.07) occurred in the BSSO group.ConclusionThe HOO presents a possible alternative to the BSSO since newly developed osteosynthesis material significantly reduces the risk of material failure. The BSSO is accompanied by higher risks of developing complications like a bad split and sensory disorders but, however, remains the standard for large anterior–posterior transpositions of the mandible.

Impact of orthognathic surgery on root resorption: A systematic review

ObjectiveThis systematic review was performed to assess the potential influence of orthognathic surgery on root resorption (RR). Material and MethodsAn electronic search was conducted using PubMed, Web of Science, Cochrane Central and Embase for articles published up to April 2022. Following inclusion and exclusion criteria, a total of six articles were selected that reported on RR following orthognathic surgery. Risk of bias assessment was performed according to the ROBINS-1 and ROB-2 tools. ResultsThe design of five studies was retrospective and one randomized clinical trial was included, with a follow-up period ranging between six months and ten years. The assessment methodologies mostly relied on two-dimensional imaging modalities where only one study used cone-beam computed tomography (CBCT) for objective quantification via linear measurements. The percentage of teeth affected by RR varied between approximately 1 and 36%, where surgically assisted rapid maxillary expansion (SARME) and Le Fort I osteotomy showed the highest percentage of RR followed by bilateral sagittal split osteotomy. ConclusionsThe present data tend to indicate that specific orthognathic procedures such as SARME and Le Fort I osteotomy may induce or reinforce RR. Yet, considering lack of evidence related to objective quantification of RR following orthodontic and/or orthognathic treatment, further CBCT-based prospective studies are required for an improved understanding of RR following different surgical procedures.

Evaluation of mandibular positional changes after orthognathic surgery in skeletal class II and class III surgery-first approach patients

PurposeThe aim of this study was to predict and compare postoperative changes of mandibular position between mandibular setback and advancement surgery in a surgery-first approach (SFA). Materials and methodsThe study population included patients who underwent mandibular setback or advancement surgery using bilateral sagittal split ramus osteotomy, those were divided into two groups: mandibular setback and advancement surgery. Surgical and postoperative mandibular positional changes were evaluated by lateral cephalograms and CTs taken within 2 months before surgery (T0), 1 week after surgery (T1), and after the debonding procedure (T2). The postoperative mandibular positional changes were predicted from the increase in vertical dimension (VD) in surgical occlusion and the counterclockwise rotation to the preoperative VD on the lateral cephalograms and CT at T1. Furthermore, resultant measurement on postoperative mandibular positional changes was performed. Finally, we compared the prediction with actual positional changes of the mandible after the debonding procedure. ResultsNine SFA patients with mandibular setback surgery and six with advancement surgery were evaluated and significant mandibular changes from T0 to T1 and from T1 to T2 were observed. Negative correlation between horizontal surgical changes and postoperative horizontal changes was present in both groups. The difference between the predicted and actual amount of postoperative mandibular movement was significant in the mandibular advancement surgery group. ConclusionPostoperative mandibular relapse appeared much larger in the mandibular advancement surgery group than in the setback group. Therefore, it is more important to consider the postoperative mandibular position change in mandibular advancement surgery in SFA.

Surgical-Orthodontic Treatment of Skeletal Class II Malocclusion with Obstructive Sleep Apnea and Multiple Missing Teeth

In the treatment of skeletal Class II retrognathic mandible, the airway should be considered for the progress and outcome of the treatment. The case report demonstrates combined orthodontic and orthognathic surgery in a 39-year-old woman with chief complaint of maxillary protrusion. The clinical examination and X-ray revealed skeletal Class II with a retrognathic mandible, high mandibular plane, vertical maxillary excess (VME), bilateral deformed condyles, and narrow posterior airway space. Moreover, the patient had several missing teeth with a posterior lingual crossbite. Polysomnography revealed obstructive sleep apnea (OSA), with a high apnea–hypopnea index (AHI) of 12.1/h. Her body mass index was low at 17.2. The preoperative orthodontic treatment included leveling, alignment, and molar uprighting. Maxillary segmental LeFort I was designed to expand her maxillary intermolar width and impact the anterior part of her maxilla. Also, bilateral sagittal split osteotomies were performed to advance her mandible position with a counterclockwise rotation of the maxillomandibular complex. The postoperative orthodontic treatment included settling the bite, monitoring the relapse, and managing the dental space for future prosthodontic rehabilitation. After a total treatment time of 1 year and 10 months, her profile was improved, her airway volume was enlarged, and her OSA was resolved, with the AHI changed to 4.3/h at 11 months after surgery then further decreased to 0/h when debonded.

Effect of modified bilateral sagittal split osteotomy on inferior alveolar nerve neurosensory disturbance

The aim of this study was to assess the occurrence of neurosensory disturbance of the inferior alveolar nerve (IAN) following modified mandibular bilateral sagittal split osteotomy (BSSO) that preserves the mandibular inferior border. All patients undergoing BSSO, associated or not with a Le Fort I osteotomy (performed by the same senior operator) between January 2018 and December 2019, were eligible. The modified BSSO consists of a modification of the technique described by Epker: the bony section of the buccal cortex stops 3-4 mm above the basal mandibular edge. While respecting the basilar border, sectioning is then performed up to the gonial angle where bicortical section is finally performed. Sensibility of the labial and chin area was evaluated immediately postoperatively, and at six months and two years of follow up. A total of 140 eligible patients underwent the modified BSSO between January 2018 and December 2019, and 72 were included. Hypoaesthesia was found in 81.9% of the patients (59/72 patients) at initial evaluation. It decreased to 45.8% (33/72 patients) at the six-month examination and to 12.5% (9/72 patients) at the last examination. Four bad splits were recorded. The modified BSSO preserves the inferior border of the mandible and maintains the IAN in the lingual fragment. There is no need to release the IAN, hence its manipulation is reduced and the incidence of IAN postoperative hypoaesthesia is also reduced.

Risk factors of neurosensory disturbances at 1 year postoperatively after bilateral sagittal split osteotomy

To investigate morphologic and surgical risk factors causing neurosensory disturbances (NSDs) after bilateral sagittal split osteotomy (BSSO). A total of 237 patients (with 474 sides) who underwent BSSO were followed up for 1 year. Parameters examined included age, sex, asymmetry, mandibular movement direction, mandible cutting devices, split type, intraoperative exposure of the inferior alveolar nerve (IAN), contact between the IAN and screw, distance between mandibular canal and inner surface of the cortical bone (distance A), distance from lateral osteotomy to mental foramen (distance B), and NSD at 1 year postoperatively. NSD was observed in 62 (13.1%) sides of 51 patients. Exploratory factor analysis determined 4 factors (factor 1: distance A; factor 2: direction of mandibular movement; factor 3: distance B and cutting devices; factor 4: IAN exposure). Logistic regression analysis was performed using the above factors and age, sex, and asymmetry, making a total of 7 variables. Age, factor 1, and factor 4 were significant predictors of NSD. Advanced age, close distance between mandibular canal and inner surface of the cortical bone, and IAN intraoperative exposure are risk factors for NSD 1 year postoperatively. Cases at high risk for NSD must be treated with great care.

How Much Opioid Medication Do Patients Need After Orthognathic Surgery?

Opioid misuse is a public health crisis. It is incumbent upon surgeons to understand analgesic requirements for operations they perform to inform responsible prescribing practices. The purpose of this study was to quantify opioid use following orthognathic surgery. This is a prospective cohort study including consecutive patients that had orthognathic surgery at the Boston Children's Hospital from May 2020 to September 2021. To be included, subjects had to have had a Le Fort I osteotomy, bilateral sagittal split osteotomies, or both. Subjects were excluded if they had a craniofacial syndrome (not including cleft lip and palate) or did not complete the study. Postoperative prescriptions and instructions were standardized. The primary outcome variable was total postoperative opioid use (inpatient+outpatient). Inpatient opioid delivery was recorded from the electronic medical record. Outpatient opioid use was ascertained via electronic questionnaire each day for 7 postoperative days. Descriptive and analytic statistics were calculated. Thirty-five subjects (54% male, age 18.7±2.7years) were included. Thirty-two subjects (91%) used postoperative opioid analgesia as inpatients, outpatient, or both, with mean total use of 18.2±20.9 morphine milligram equivalents/subject (equivalent to 7.3±8.4 oral oxycodone 5-mg doses). Nine (26%) subjects received inpatient opioid but did not use any oral opioid after discharge. As outpatients, a mean of 3.9±5.5 oral oxycodone 5-mg dose was used per patient over 2.1±2.1 postoperative days. Le Fort I osteotomy-only procedures had significantly lower (P=.032) and combined Le Fort I osteotomy and bilateral sagittal split osteotomy operations had significantly higher (P=.003) opioid requirements than the mean. Length of procedure and hospital length of stay were significant predictors of analgesic need, with an increase of 0.34 oxycodone doses/subject for each 10-minute increase in procedure time and 0.20 oxycodone doses/subject for each 1-hour increase in length of stay. Pain level on the first postoperative day was also a predictor of total opioid use (P<.050). Opioid use after orthognathic surgery is less than expected. Caution is necessary to avoid overprescribing.

Partial Bone Necrosis Following Sagittal Split Ramus Osteotomy: Report of a Complicated Orthognathic Jaw Surgery

Study Design Case Report. Objective To present a case of a previous complicated mandibular orthognathic surgery that aimed to setback the mandible in a female cleft lip and palate (CLP) patient, which led to bone necrosis on one side with subsequent severe mandibular deviation and facial asymmetry. We additionally reviewed the previous reports of similar complications, the pathophysiology and the factors that could lead to this dreadful result. Method A 27-year-old female patient presented with a severe dentofacial deformity secondary to a complicated bilateral sagittal split ramus osteotomy performed five years earlier, which resulted in aseptic bone necrosis on the right side. The patient had marked mandibular deviation, chin and midface retrusion and a pronounced occlusal discrepancy. Imaging demonstrated a bony defect at the right mandibular angle with a superiorly displaced proximal segment. Deviation of the mandible was corrected first by performing vertical ramus subsigmoid osteotomy (RSO) on the left side. The right bone defect was then reconstructed with a reconstruction plate and bone grafting. Maxillary and chin advancement was performed at a second stage. Results On follow-up, the patient shows a significant improvement in facial esthetics and mandibular symmetry and is currently under orthodontic management to enhance the occlusal relationship. Conclusion Bone necrosis is a rare but dreaded problem in orthognathic surgery. Minimizing the musculo-periosteal dissection and competent execution of the bone osteotomy is substantially effective in reducing the risk of bone ischemia and necrosis.

Ortho-surgical treatment in Class II skeletal patients with mandibular retrognathism: a concise systematic review

Introduction: In the setting of class II malocclusion corrections, the union of orthodontic and surgical procedures was developed. Bilateral sagittal split osteotomy is standard protocol for correcting mandibular retrognathism. Class II dental malocclusion with deep bite needs to be treated early by orthodontics. Thus, the commonly used technique combines BSSO for mandibular advancement and recoil genioplasty to correct the resulting chin protrusion. Objective: To carry out a systematic review of the main considerations of ortho-surgical treatments in class II patients with mandibular retrognathism. Methods: Experimental and clinical studies (case reports, retrospective, prospective and randomized) with qualitative and/or quantitative analysis were included, following the rules of the systematic review-PRISMA. Results and Conclusion: A total of 128 articles was found involving class II malocclusion and ortho-surgical treatments. After, a total of 64 articles were fully evaluated and 24 were included and discussed in this study. A meta-analysis study evaluated the best functional appliance improving mandibular length in individuals with retrognathism. Sander Bite Jumping reported the greatest increase in mandibular length, with 3.40 mm. Another meta-analysis study compared dental, skeletal, and aesthetic outcomes between orthodontic camouflage and orthodontic-surgical treatment in patients with Class II skeletal malocclusion and retrognathic mandible with anterior growth. The difference between treatments was not statistically significant regarding SNA angle, linear measure of the lower lip to the Ricketts aesthetic line, convexity of the skeletal profile or soft tissue profile excluding the nose. In contrast, orthodontic-surgical treatment was more effective to the ANB, SNB and ML/NSL angles and the soft tissue profile including the nose.

A level set approach to high fidelity interactive bone shaving for virtual training of surgical osteotomies.

Interactive multimodal surgical simulators are powerful tools that allow efficient and objective assessment of surgical skills. Bilateral Sagittal Split Osteotomy (BSSO) requires precise cutting of the mandible with a motorized saw that cannot afford a high margin of error. Surgeons rely on visual and haptic cues that are hard to train for through existing curricula without training directly on patients. In this paper, we present a new algorithm to achieve low-cost, precise sawing of the bone that is capable of providing realistic force feedback to the user at haptic rates (~1000Hz). Our method is centered around treating the bone surface as a level set that is evolved at interactive rates upon user's interaction with the virtual saw. The movement of the virtual saw itself is governed by a rigid body solver which is attached to the pose (6 degrees of freedom) of the haptic device via a mass-spring-damper which also supplies haptic force feedback. Our method allows parameterization of the erosion rate, saw speed, and bone density thus making it suitable to any material shaving application including dentistry (e.g., tooth milling) and a variety of surgical osteotomies.

Multi-segmented maxillary ortho-surgical treatment in Class II patients with maxillary protrusion and open bite: a concise systematic review

Introduction: Anterior open bite is the lack of vertical contact or negative overbite between the anterior teeth of the upper and lower arches when the posterior teeth are in occlusion. Its etiology is multifactorial, including heredity, oral habits, unfavorable growth patterns, and increased lymphatic tissue along with mouth breathing and functional oral matrices. The characteristics of individuals with anterior open bite include excessive gonial, mandibular, and occlusal plane angles, mandibular small body, and ramus increased lower anterior facial height, decreased upper anterior facial height, retrusive jaw, Class II tendency, divergent cephalometric planes, lingual position, and inadequate lip seal. Objective: To carry out a concise systematic review of multi-segmented maxillary ortho-surgical treatment in class II patients with maxillary protrusion and open bite. Methods: Experimental and clinical studies (case reports, retrospective, prospective and randomized) with qualitative and/or quantitative analysis were included, following the rules of the systematic review-PRISMA. A total of 289 articles were initially found and, after selection, 17 articles were used to compose this study. Results and conclusion: Significant improvement in anterior occlusion can be expected in most patients when maxillary or mandibular surgery is used for Class II open bite correction. However, there will be individual patients in whom there will be considerable post-treatment changes in the anteroposterior and vertical dimensions. Although individual morphology needs to be taken into account, it appears that both short-term and long-term stability are likely to be greater after Le Fort I surgery compared to bilateral sagittal split osteotomy.

Lateral cephalometric changes and stability of BSSO versus IVRO for mandibular setback surgery: A systematic review and meta-analysis.

The aim of this review is to examine the lateral cephalometric hard tissue changes and the stability of the end result of bilateral sagittal split osteotomy (BSSO) and the intraoral vertical ramus osteotomy (IVRO) techniques for mandibular setback surgery. A systematic review of MEDLINE (via PubMed), Scopus, and Cochrane Library databases (last search date: August 22nd, 2021) was performed according to the PRISMA guidelines. Only studies that directly compare BSSO and IVRO were included. Random-effects model meta-analyses were performed. Ten studies, comprising a total of 331 patients, 169 patients undergoing BSSO and 162 patients undergoing IVRO were identified. No statistically significant differences were observed regarding the angular measurements: Sella/Nasion/B point (SNB) angle post-operatively (standardized mean difference [SMD]= 0.39, 95% Confidence Interval [CI]: [-0.15] – [0.94], p=0.16, I2=57.09%) and 1 year after surgery (SMD= 0.72, 95% CI: [-0.08] – [1.53], p=0.08, I2=80.83%), gonial angle post-operatively (SMD=0.45, 95% CI: [-0,26] – [1.15], p=0.21, I2=72.54) and 1 year after surgery (SMD= 0.15, 95% CI: [-0.79] – [1.08], p=0.75, I2=91.56%), and MP angle 1 year after surgery (SMD=-0.46, 95% CI: [-1.64] – [0.72], p=0.45, I2=90.81%). In addition, no statistically significant differences were observed regarding the linear measurements, the relapse of the mandible as measured by the relapse of B point 1 year after surgery in the horizontal axis (SMD= 0.73, 95% CI: [-0.25] – [1.72], p=0.15, I2=86.43%) and vertically (SMD= -0.76, 95% CI: [-1.97] – [0.45], p=0.22, I2=90.09%). BSSO and IVRO have similar results in terms of SNB and gonial angle relapse post-operatively and 1 year after surgery, MP angle 1 year after surgery and horizontal and vertical relapse, measured in reference to B point 1 year after surgery.

Virtual surgical analysis: long-term cone beam computed tomography stability assessment of segmental bimaxillary surgery

The assessment of the stability of orthognathic surgery is often time-consuming, relies on manual re-identification of anatomical landmarks, and has been based on short-term follow-up. The purpose of this study was to propose and validate a semi-automated approach for three-dimensional (3D) assessment of the long-term stability of segmental bimaxillary surgery. The approach was developed and validated using cone beam computed tomography scans obtained at 2 weeks and 2 years postoperative. The stability of the surgical outcome was calculated as 3D translational and rotational differences between the short- and long-term postoperative positions of the individual bone segments. To evaluate reliability, intra-class correlation coefficients were calculated at a 95% confidence interval on measurements of two observers. Ten class II and III patients (six male, four female; mean age 24.4 years), who underwent a combined three-piece Le Fort I osteotomy, bilateral sagittal split osteotomy, and genioplasty, were included in the study. Intra- and inter-observer reliability were excellent (range 0.82–0.99). The range of the mean absolute difference of the intra- and inter-observer translational and rotational measurements were 0.14 mm (0.13)–0.44 mm (0.50) and 0.20° (0.16)–0.92° (0.78). The approach has excellent reliability for 3D assessment of long-term stability of segmental bimaxillary surgery.

Evaluation of lingual fracture pattern of the mandible after bilateral sagittal split osteotomy with and without inferior border osteotomy

The Purpose of the study was to evaluate the pattern of lingual split when performing a bilateral sagittal split osteotomy (BSSO) with different osteotomy methods. A total of 15 dry human cadaveric mandibles was taken for the study. The classical Epker technique of BSSO was performed on the left side. The same was done on the right side along with an-additional inferior border osteotomy. There resultant split was assessed based on modified lingual split scale. The maximum torque force that was needed to split the mandible was recorded and the fracture pattern was observed. Similar osteotomies were performed in 15 fresh goat mandibles which acted as control group. The human cadaveric dry mandible recorded an average torque of 12.6 +2.4 Nm (SD: 0.32) with a maximum of 16.0 Nm and a minimum of 8.0 Nm on left side.80% of the mandible were Type I fracture pattern and 20% had Type III fracture pattern. In contrast with the modified BSSO technique with an additional inferior border osteotomy required a maximal torque of 12.0 N and a minimal torque of 5.0 with an average required torque of 8.7 + 2.1 N on the right side of the mandible.