Bad splits in bilateral sagittal split osteotomy: systematic review of fracture patterns

Bilateral sagittal split osteotomy with or without concomitant removal of third molars: a retrospective cohort study of related complications and bone healing

PURPOSE

To carry out a comparative evaluation of the intra- and postoperative complications, and bone healing, following bilateral sagittal split osteotomy (BSSO) with or without concomitant removal of third molars.

MATERIAL AND METHODS

A retrospective analysis was performed of two cohorts subjected to BSSO with the intraoperative removal of third molars (test group) versus the removal of third molars at least 6 months prior to BSSO (control group), comprising at least 1 year of clinical and radiographic follow-up. Partially or completely erupted third molars were extracted immediately before completing the osteotomy, whereas impacted third molars were removed after the osteotomy had been performed. Hardware reinforcement was performed in bimaxillary cases where concomitant molar extraction impeded placement of the retromolar bicortical screw of the hybrid technique.

RESULTS

A total of 80 surgical sites were included (40 in each group). Concomitant extraction of the molar represented a mean increase in surgery time of 3.7 min (p < 0.001). No additional complications occurred in the test group (p = 0.476). The gain in bone density was preserved in both groups (p = 0.002), and the increase was of the same magnitude in both (p = 0.342), despite the fact that the immediate and final postoperative bone densities were significantly higher in the control group (p = 0.020).

CONCLUSION

The results obtained support concomitant molar extraction with BSSO as a feasible option.

Determining the safety margin of mandibular lingula in sagittal split ramus osteotomy

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.

Exploring the relationship between the number of systematic reviews and quality of evidence: an orthognathic surgery-based study

OBJECTIVE

We analyzed the quality and quantity of systematic reviews (SRs) of orthognathic surgery, the most frequently published topic in maxillofacial surgery.

STUDY DESIGN

We searched the PubMed database for SRs of orthognathic surgery with no restriction on the language of publication date. We assessed the certainty of evidence presented according to the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocol and the Leiden Manifesto using the Grading of Recommendations Assessment, Development, and Evaluation approach. We analyzed the data using descriptive statistics, Pearson´s correlation test, and linear regression.

RESULTS

Of the 171 SRs evaluated, approximately one fifth presented evidence with a high level of certainty. The number of orthognathic surgery SRs has been increasing, and many SRs were published after very similar topics had already been published. There is no relationship between the impact factor and the certainty of evidence.

CONCLUSIONS

An excessive number of SRs of orthognathic surgery are published, and many SRs are superfluous, simply reporting previous findings. Clinicians should not base treatment decisions solely on the evidence presented in SRs, and journal editors and reviewers should evaluate these SRs more critically, particularly when they address topics that have already been covered in the literature.

Clinical Stability of Bespoke Snowman Plates for Fixation following Sagittal Split Ramus Osteotomy of the Mandible

Maxillofacial skeletal surgery often involves the use of patient-specific implants. However, errors in obtaining patient data and designing and manufacturing patient-specific plates and guides can occur even with accurate virtual surgery. To address these errors, bespoke Snowman plates were designed to allow movement of the mandible. This study aimed to compare the stability of bespoke four-hole miniplates with that of a bespoke Snowman plate for bilateral sagittal split ramus osteotomy (SSRO), and to present a method to investigate joint cavity changes, as well as superimpose virtual and actual surgical images of the mandible. This retrospective study included 22 patients who met the inclusion criteria and underwent orthognathic surgery at a university hospital between 2015 and 2018. Two groups were formed on the basis of the plates used: a control group with four-hole bespoke plates and a study group with bespoke Snowman plates. Stability was assessed by measuring the condyle-fossa space and superimposing three-dimensional virtual surgery images on postoperative cone-beam computed tomography (CBCT) scans. No significant differences were observed in the condyle-fossa space preoperatively and 1 year postoperatively between the control and study groups. Superimposing virtual surgery and CBCT scans revealed minimal differences in the landmark points, with no variation between groups or timepoints. The use of bespoke Snowman plates for stabilizing the mandible following SSRO exhibited clinical stability and reliability similar to those with bespoke four-hole plates. Additionally, a novel method was introduced to evaluate skeletal stability by separately analyzing the condyle-fossa gap changes and assessing the mandibular position.

Computed tomography evaluation of risk factors for an undesirable buccal split during sagittal split ramus osteotomy

Sagittal split ramus osteotomy (SSRO) sometimes induces an irregular split pattern referred to as a bad split. We investigated the risk factors for bad splits in the buccal plate of the ramus during SSRO. Ramus morphology and bad splits in the buccal plate of the ramus were assessed using preoperative and postoperative computed tomography images. Of the 53 rami analyzed, 45 had a successful split, and 8 had a bad split in the buccal plate. Horizontal images at the height of the mandibular foramen showed that there were significant differences in the ratio of the forward thickness to the backward thickness of the ramus between patients with a successful split and those with a bad split. In addition, the distal region of the cortical bone tended to be thicker and the curve of the lateral region of the cortical bone tended to be smaller in the bad split group than in the good split group. These results indicated that a ramus shape in which the width becomes thinner towards the back frequently induces bad splits in the buccal plate of the ramus during SSRO, and more attention should be paid to patients who have rami of these shapes in future surgeries.

Correlation between mandibular anatomy and bad split occurrence during bilateral sagittal split osteotomy: a three-dimensional study

OBJECTIVES

This study aimed to find out the correlation between different anatomical parameters of the mandible and the occurrence of a bad split in patients who had undergone bilateral split sagittal ramus osteotomy (BSSRO).

MATERIALS AND METHOD

At both the distal roots of the first molar (1) and the retromolar area (2), we measured the distance from the buccal margin of the inferior dental canal (IDC) to the buccal margin of the cortical bone (MCBC), the thickness of both buccal cortical (WBCB) and cancellous bone (WBCA), distance from the superior border of IDC to the alveolar crest (MCAC), buccolingual thickness (BLT), and thickness of cancellous bone (WCA). At the ramus, the distances between the sigmoid notch to the upper part of the lingula (SL) and the inferior border of the mandible (SIBM), the thickness of the ramus at the level of the lingula (BLTR), and the anteroposterior width of the ramus (APWR) were measured. The paired and independent t-tests were used when applicable, and a P-value < 0.05 was considered significant.

RESULTS

MCBC1 showed a significant difference between bad and non-bad split sides (P = 0.037). Both WBCA1 and WBCA2 show the same significant difference (P = 0.023, 0.024). Similarly, WCA1 and WCA2 showed a statistical difference between the bad and non-bad split sides (P = 0.027, 0.036). There were no statistically significant differences between the compared sides of WBCB1, WBCB2, MCAC1, MCAC2, SIBM, APWR, SL, and BLTR.

CONCLUSION

Narrow space between IDC and the buccal cortical margin, along with the decrease in the thickness of both buccal cancellous bone and total cancellous bone at the inferior border of the mandible along the course of SSRO, has been implicated in the occurrence of bad split intraoperatively.

Mandibular asymmetry: Is there a difference in the bone and soft tissue thickness between both sides?

OBJECTIVE

The asymmetric mandible presents the clinician with unique anatomic challenges in orthognathic surgery correction. This study aims to investigate these characteristics of the asymmetric mandible: mandible bone thickness, soft tissue thickness, and the proximity of the bone cortex to the inferior alveolar nerve (IAN) canal.

STUDY DESIGN

Three-dimensional virtual models were created of 35 participants of Asian descent with mandibular asymmetry. Mandibular bone thicknesses and soft tissue thicknesses were measured at certain landmarks. Statistical analysis of the thicknesses of both sides of the mandible was performed. Comparison of thicknesses between patients with minor and major asymmetry were also performed.

RESULTS

The bone was significantly thinner at the longer side at all 4 mandible landmarks (P < .001). The bone lateral to the IAN was significantly thinner at the longer side, as well (P < .001). The soft tissue thickness did not differ significantly across sides, except at 1 landmark. These findings were even more exaggerated in the major asymmetry group.

CONCLUSIONS

The longer side of the asymmetric mandible bone was thinner, and the bone lateral to the IAN was also thinner as a result. This asymmetric thinness was exaggerated in patients with severe asymmetry, which may predispose the longer side to IAN injury and unfavorable fractures. The differences in bone thickness in the asymmetric mandible may also result in residual postoperative asymmetry.

Determining Morbidity of Adding Genioplasty to Bimaxillary Orthognathic Surgery

BACKGROUND

Patients with dentofacial anomalies may undergo orthognathic surgery to address functional and aesthetic concerns. Past works have evaluated determinants affecting length of stay (LOS) in patients undergoing upper and/or lower jaw surgery alone. No studies have assessed the addition of genioplasty to double-jaw (Lefort I, bilateral sagittal split osteotomy (BSSO))) surgery and its effect on LOS and other outcomes. This study investigates whether the addition of genioplasty incurs additional morbidity to patients undergoing complex orthognathic surgery.

METHODS

This was a retrospective cohort study of patients undergoing orthognathic surgery at Yale-New Haven Hospital. Clinical and demographic information were compared across the "double"- and "triple"-jaw cohorts with t tests and Chi-squared analyses. Multivariable linear and logistic regression analyses were utilized to assess the impact of genioplasty when controlling for baseline patient differences.

RESULTS

A total of 27 patients received Lefort I and BSSO (double-jaw), and 224 received Lefort I, BSSO, and genioplasty (triple-jaw). Six (22.2%) double-jaw patients were segmental and fifty-eight (25.9%) triple-jaw patients were segmental (p > 0.05), during the study period. Triple-jaw surgery was associated with increased operative time (+ 41.1 min, p < 0.01). There was no increase in LOS, postoperative nausea and vomiting, opioid use, hematoma, or infection (p > 0.05).

CONCLUSIONS

This study attempted to determine if triple-jaw surgery could influence patients' LOS and other surgical outcomes compared to double-jaw surgery. Only the operative time was significantly affected. This indicates that incorporation of a genioplasty can provide aesthetic benefit without incurring significant additional morbidity to the patient.

LEVEL OF EVIDENCE III

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 .

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.

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

PURPOSE

To 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.

METHODS

The 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.

RESULTS

Two 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.

CONCLUSION

The 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.

Virtual Reality and Three-Dimensional Printed Models Improve the Morphological Understanding in Learning Mandibular Sagittal Split Ramus Osteotomy: A Randomized Controlled Study

Background: The mandibular sagittal split ramus osteotomy (SSRO) is a routine operation performed to correct mandibular deformity including mandibular retrusion, protrusion, deficiency, and asymmetry. The SSRO remains a challenging procedure for junior surgeons due to a lack of adequate morphological knowledge necessary for success in clinical practice. Virtual reality (VR) and three-dimensional printed (3DP) models have been widely applied in anatomy education. The present randomized, controlled study was performed to evaluate the effect of traditional educational instruments, VR models, and 3DP models on junior surgeons learning the morphological information required to perform SSRO.

Methods: Eighty-one participants were randomly assigned to three learning groups: Control, VR, and 3DP. Objective and subjective tests were used to evaluate the learning effectiveness of each learning instrument. In the objective test, participants were asked to identify 10 anatomical landmarks on normal and deformed models, draw the osteotomy line, and determine the description of SSRO. In the subjective test, participants were asked to provide feedback regarding their subjective feelings about the learning instrument used in their group.

Results: The objective test results showed that the VR and 3DP groups achieved better accuracy in drawing the osteotomy line (p = 0.027) and determining the description of SSRO (p = 0.023) than the Control group. However, there was no significant difference among the three groups regarding the identification of anatomical landmarks. The VR and 3DP groups gave satisfactory subjective feedback about the usefulness in learning, good presentation, and enjoyment. The Control and 3DP groups reported positive feelings about ease of use.

Conclusion: The current findings suggest that VR and 3DP models were effective instruments that assisted in the morphological understanding of SSRO-related anatomical structures. Furthermore, 3DP models may be a promising supplementary instrument to bridge the gap between conventional learning and clinical practice.

Risk Factors Analysis for Different Types of Unfavorable Fracture Patterns During Sagittal Split Ramus Osteotomy: A Retrospective Study of 2008 Sides

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 .

Dal Pont vs Hunsuck: Which Technique Can Lead to a Lower Incidence of Bad Split during Bilateral Sagittal Split Osteotomy? A Triple-blind Randomized Clinical Trial

BACKGROUND

We aimed to assess the incidence of bad split fractures during Bilateral Sagittal Split Osteotomy (BSSO) mandibular setback surgery using Dal Pont and Hunsuck techniques.

METHODS

All healthy adults with skeletal class III discrepancy, who were candidates for mandibular setback surgery were enrolled in this randomized clinical trial in the Maxillofacial Surgery Department of Qaem Hospital, Mashhad, Iran; from 2018-2020. These patients were randomly divided into two equal groups; one group underwent BSSO using Dal Pont osteotomy while the Hunsuck osteotomy was employed for the other group. A bad split fracture which identified through intra-operative clinical and postoperative radiographic examination was the outcome variable. The significance level was set at 0.05 using SPSS 16.

RESULTS

Overall, 104 consecutive patients, comprising of 52 (50%) males with an average age of 23.09±3.08 were recruited. The average duration of osteotomy and splitting was reported to be 22.74±3.06 min. 10 bad split fractures (9.62%) were observed; 7 of which occurred in the Dal Pont group and 3 in the Hunsuck group. However, this difference was not significant. In 80% of the cases, bad split osteotomy occurred in the proximal segment, while this finding was identified in the distal segment in 20% of cases. The average duration of osteotomy and splitting was significantly longer in the Dal Pont group (P<0.001).

CONCLUSION

The duration of osteotomy and splitting is much shorter when the Hunsuck technique is employed, and the incidence of unfavorable fractures is also less compared to the Dal Pont osteotomy technique.

Complications related to orthognathic surgery: A 10-year experience in oral and maxillofacial training center

This article aimed to review adverse events and complications to orthognathic surgery based upon 10 years. This study was a retrospective investigation between 2009 and 2018. Independent variables such as sex, age, pre-operative conditions, diagnosis, type of surgery, bleeding volume, surgery duration, and hospitalization were recorded. The data regarding orthognathic surgery adverse events and complications were evaluated and statistically analyzed with a significance level of p < 0.05. A total of 891 patients were included in this study (male 39.1%, female 60.9%) with a mean age of 26.4 ± 6.09 years. A neurosensory disturbance was found as immediate post-operative sequelae as 93.5%. The four most frequent complications had a relapse (6.4%), post-operative TMD (5.7%), unfavorable osteotomy (5.5%), and infection (4.9%), which seem to be more common in males. An average blood loss was 497 ± 371 ml and the average operative time was 401 ± 109.3 min. Complication rates were statistically affected by bleeding volume (p-value = 0.01), operative time (p-value = 0.03), and type of skeletal deformity (p-value = 0.01). Although numerous complications were recorded, no fatal complications were experienced. Bleeding time, operative time, and skeletal classification have significant influence on orthognathic surgery complications. However, a multitude of factors could be modified to reduce the complication rate and improve the result of the treatment. One of the most significant factors was the operative time.

Differences in the Buccal Bone Marrow Distance of ≤0.8 mm in the Mandible of Patients Undergoing Sagittal Split Ramus Osteotomy among the Different Skeletal Patterns: A Retrospective Study

This study investigated the relationship between the thickness of the ramus and skeletal patterns using cone-beam computed tomography (CBCT) for sagittal split ramus osteotomy. Ninety participants were categorized into three skeletal patterns (Class I, Class II, and Class III). The first vertical slice (slice 0) was observed in the intact mandibular canal, and then moved forward to 40 mm (slice 21) with a 2 mm interval. The thickness of buccal bone marrow (B value) was measured. A B value of ≤0.8 mm was considered to be the major risk factor causing the occurrence of postoperative lower lip paresthesia. There were 461 sides with a B value of ≤0.8 mm. There was a significant difference in the skeletal patterns [Class III (198 sides: 15.7%) > Class I (159 sides: 12.6%) > Class II (104 sides: 8.3%)]. Class II participants had significantly larger B values (2.14 to 3.76 mm) and a lower occurrence rate (≤0.8 mm) than those of Class III participants (1.5 to 3 mm) in front of the mandibular foramen (from 6 mm to 20 mm). Class III participants had significantly shorter buccal bone marrow distance and a higher occurrence rate of B values (≤0.8 mm) than Class II.

Classification and Clinical Treatments for Unfavorable Fractures of the Proximal Segment in Sagittal Spilt Ramus Osteotomy: A Retrospective Study of 964 Cases

ABSTRACT

Unfavorable fractures in sagittal split ramus osteotomy are hard to manage. The aim of this study is to develop a new classification method for unfavorable fractures of the proximal segment to guide clinical managements. After reviewing 964 cases of sagittal split ramus osteotomy, we found that the unfavorable fractures can be divided into 3 types: mandibular ramus transverse fractures (Type 1), bad fractures accompanied by free fragments (Type 2), and unexpected separation patterns without free fragments (Type 3). We calculated the incidence of each fracture type and provided instructions for their corresponding treatments. Thirty-six patients suffered from unfavorable fractures (7.4% of patients), among which 32 patients had unilateral fractures and 4 patients had bilateral fractures. There were 2 Type 1 fractures (0.2% of split sites), 8 Type 2 fractures (0.8% of split sites), and twenty-six Type 3 fractures (2.3% of split sites). Type 1 unfavorable fractures are difficult to deal with, but Types 2 and 3 are generally manageable and they have no significant impact on the final outcomes. The new classification can effectively guide treatment strategies for unfavorable fractures. Severe cases of unfavorable fractures are rare, and most unfavorable fracture cases have a positive prognosis if correctly treated in time.

Orthognathic Surgery of the Mandible

Orthognathic surgery performed in conjunction with orthodontic treatment is commonly performed to correct skeletal irregularities and realign the maxillomandibular relationship to improve occlusal function and facial esthetics. A thorough understanding of soft tissue esthetics, skeletal and occlusal relationships, and surgical techniques is required to obtain successful results. Surgical techniques have evolved greatly throughout history, as technological advances such as virtual surgical planning have become available and widely used to obtain predictable movements with minimized complications. The aim of this article is to review the orthognathic surgical procedures of the mandible, with particular attention to the indications, contraindications, preoperative assessment, surgical technique, and possible complications encountered.

Quantitative Morphometric Analysis of Anatomical Landmarks Involved in Bilateral Sagittal Split Osteotomy in Different Skeletal Malocclusions Using Cone-Beam Computed Tomography

BACKGROUND

To assess and compare the anatomical landmarks involved in bilateral sagittal split osteotomy (BSSO) in different skeletal malocclusions quantitatively using cone-beam computed tomography (CBCT).

METHODS

This retrospective study evaluated 63 CBCT scans of the three malocclusion classes (n = 21). Twenty-one quantitative variables were measured and compared between different malocclusion classes. One-way ANOVA, Welch test, Kruskal Wallis test and the Mann-Whitney test with Bonferroni adjustment were used for data analysis. The level of significance was set at ≤0.05.

RESULTS

The patients had a mean age of 26.35 years (range 18-58 years). The width of the lateral cortex in the posterior third (T1-P) of ramus in the left side, and the mean value in the right and left sides were significantly different between different classes of malocclusion (P = 0.049) such that class II patients had significantly thinner lateral cortex. No other significant differences were noted between different malocclusion classes in other variables.

CONCLUSION

The quantitative morphological assessment of the mandible in BSSO of different malocclusion classes did not reveal significant differences. There is no superiority in the dimensions of discussed landmarks involved in BSSO among different malocclusion classes. So the risk or the safety of this kind of surgery is similar for these classes. Thus, diagnostic preoperative workup by CBCT is imperative for selection of a surgical approach with minimal postoperative complications.

Major Complications and Associated Risk Factors for Osseous Genioplasty with Bimaxillary Orthognathic Surgery: An American College of Surgeons-National Surgical Quality Improvement Program Analysis

PURPOSE

Patients with significant dentofacial deformities undergoing aesthetic and functional orthognathic surgery may often require genioplasty to advance the position of the pogonion relative to B point. No study to date has evaluated nationally registered data pertaining to addition of osseous genioplasty to bimaxillary orthognathic surgery and its associated clinical outcomes.

METHODS

Data was extracted from the National Surgical Quality Improvement Program from 2010 to 2018 using current procedural terminology codes pertaining to Le Fort I osteotomy (LF), bilateral sagittal split osteotomy (BSSO), and osseous genioplasty (G) and divided into 2 cohorts: bimaxillary orthognathic surgery with and without osseous genioplasty. Thirty-day postoperative outcomes inherently recorded within National Surgical Quality Improvement Program were identified and recorded. Chi-squared analysis and unpaired 2-tail t tests were performed between the cohorts and their respective outcomes to determine significant relationships with significance set as P < 0.05.

RESULTS

There were 373 patients double- or triple-jaw patients identified from the years 2010 to 2018. The most common recorded indication for LF/BSSO was maxillary hypoplasia (27.3%) and mandibular hypoplasia (6.8%). The most common indications for LF/BSSO/G were maxillary hypoplasia (16.1%) and maxillary asymmetry (16.1%). In comparison to LF/BBSO only, LF/BSSO/GP was not associated with any differences in the rate of surgical (0.0% versus 0.31%, P = 0.72) or medical complications (0.0% versus 0.63%, P = 0.60), in addition to unplanned readmissions (0.0% versus 1.56% versus P = 0.41) or reoperations (0.0% versus 1.25%, P = 0.46). However, osseous genioplasty addition was associated with increased overall operating time (271.77 versus 231.75 minutes, P = 0.04).

CONCLUSIONS

Osseous genioplasty does not alter short-term, 30-day complication rate when performed with bimaxillary orthognathic surgery. As reoperation rates remained relatively unchanged, it can be inferred that immediate adverse events or patient dissatisfaction were not apparent within 30 days. Although mean operating time is slightly longer, cardiopulmonary resuscitation without medical comorbidity was achieved at the conclusion of the procedure.

Effect of Horizontal Osteotomy Level on Complication Rates and Neurosensory Deficits After Sagittal Split Ramus Osteotomy

Horizontal osteotomy is one of the most critical step at sagittal split ramus osteotomy (SSRO) and determination of the ideal height of this horizontal osteotomy is essential to avoid nerve and vessel injury.

PURPOSE

The aim of this study was to evaluate the level of the medial horizontal ramus cut as a risk factor for unfavorable outcomes in the SSRO.

MATERIALS AND METHODS

Sixty-four patients with dentofacial deformity who applied to Oral & Maxillofacial Surgery Department between August 2018 and August 2019 and undergone orthognathic surgery were evaluated. Out of 64, 49 patients had SSRO with or without maxillary surgery and genioplasty. Twenty-six patient had postoperative computed tomography scan with 6-months follow-up. Finally, 26 patient with 52 SSRO sides were included in this study. Computed tomography scans were evaluated and classification according to osteotomy levels was made. Postoperative neurosensory deficit, bleeding, and intraoperative complications such as bad split, visible damage to inferior alveolar bundle were assessed. Age, gender, neurosensory deficit, bad splits were analyzed and correlated with the level of the osteotomies.

RESULTS

Fifteen osteotomies were above lingula, 24 between apex and base of lingula, and 14 below lingula. One bad split occurred, and no visible damage to the inferior alveolar bundle was seen. There was no significant difference between osteotomy groups in terms of visual analogue scale (VAS) scores (P > 0.05) but in all groups; women's VAS scores are statistically significantly higher than men. (P: 0.036).

CONCLUSION

There is no correlation between the horizontal osteotomy level and intraoperative or postoperative complications. The low medial horizontal osteotomy can be safely performed in SSRO.

Spontaneous bilateral coronoid process fracture of the mandible after BSSO: A case report

A patient with spontaneous bilateral fracture of the mandibular coronoid process is presented. The definite cause is unknown, but possible contributing factors include osteoporosis, bruxism and changed kinetics of the temporalis muscle after bilateral sagittal split osteotomy (BSSO) resulting in an avulsion fracture. The patient was treated surgically with bilateral coronoidectomy.

Orthognathic surgery complications: The 10-year experience of a single center

The retrospective cohort study aimed to assess the incidence and characteristics of these complications in patients who underwent orthognathic procedures. Data on the intraoperative and the postoperative complications were extracted from the patients' medical files. Procedures were further subdivided into single-jaw procedures and bimaxillary procedures. A total of 209 orthognathic procedures were carried out in 190 patients. 184 (88%) were performed to treat angle class III malocclusion, while 25 (12%) aimed to treat class II malocclusion. A total of 94 complication events were observed (44.9% of 209 procedures). 22 of them occurred in single-jaw procedures (28.2% of 78 single jaw operations), and 72 occurred in bimaxillary procedures (55% of 131 bimaxillary operations). When compared regarding the type of complication, complication rates were comparable between the study groups with the exception of late-stage malocclusion. A significant difference (p-value = 0.028) in malocclusion incidences between the bimaxillary and single-jaw groups were observed (9 events, 4.3% and zero events, 0%, respectively). The majority of the complications during and following orthognathic surgical procedures are temporary or minor and require little or no treatment at all.

Postoperative CT findings of orthognathic surgery and its complications: A guide for radiologists

Orthognathic surgery is the standard procedure to correct congenital, developmental, or acquired dentofacial deformities. The maxillomandibular relationship corrected by orthognathic surgery can improve facial esthetics, masticatory function, articulation, and breathing. The most common types of osteotomies include the combination of Le Fort I osteotomy, bilateral sagittal split mandibular ramus osteotomy, and genioplasty. High-resolution low-dose computed tomography is useful for evaluating the facial skeleton and soft tissues after surgery as well as for depicting a variety of possible complications. This article reviews the postoperative imaging findings of the most common orthognathic surgeries and their potential complications on multidetector-row computed tomography.

Sagittal Split Ramus Osteotomy in the Shortest Buccal Bone Marrow Distances of the Mandible on the Coronal Plane

Purpose

This study investigated the relationship between the shortest buccal bone marrow of the ramus and skeletal patterns.

Materials and Methods

Using cone-beam computed tomography data (specifically, the A point-nasion-B point (ANB) angle), we divided patients into three groups as follows: skeletal class I (0° < ANB < 4°), class II (ANB: ≥4°), and class III (ANB: ≤0°). Sixteen vertical sections in the coronal plane were taken starting from slice 0 (original intact mandibular canal) anteriorly at 2 mm intervals to slice 15 (30 mm). The thickness of the mandible (M) and shortest buccal bone marrow (SBM) were measured. The data of SBM were divided into two groups (SBM ≥ 1 mm and SBM < 1 mm). For each skeletal pattern, an SBM value < 1 mm was considered to indicate a high possibility of postoperative nerve paresthesia and bad split.

Results

The three skeletal pattern groups also did not significantly differ in their M values for all sections. The mean SBM values of class III (0.91–2.11 mm) at 6–16 mm anterior to the mandibular foramen were significantly smaller than those of class II (1.53–3.17 mm). Comparing the occurrence ratio of SBM < 1 mm, the highest and lowest probabilities in class III (55% and 21.7%, respectively) were significantly larger at 6–20 mm anterior to the mandibular foramen than those in class II (28.3% and 5%, respectively).

Conclusion

Class III had a significantly shorter SBM distance and higher SBM occurrence probability than class II at the mandibular ramus region, implying that class III participants are more likely than class II participants to have nerve paresthesia and bad split after sagittal split ramus osteotomy.

Does the Presence of Impacted Mandibular Third Molars Increase the Risk of Bad Split Incidence During Bilateral Sagittal Split Osteotomy?

BACKGROUND

The possibility of mandibular bad spilt might happen during bilateral sagittal split osteotomy (BSSO). This study investigated the effect of impacted mandibular third molars on bad spilt incidence during BSSO.

METHODS

Totally, 140 patients under 40 years old who were candidates for BSSO surgery due to class 3 skeletal discrepancy were divided randomly into two equal groups. The impacted mandibular third molars were presented in one group during BSSO (Exposed), and the third molars were removed at least six months before surgery for the other group (Unexposed). All cases underwent BSSO using the same technique by a single surgeon. A bad split was diagnosed by inter-operative clinical examination and postoperative panoramic radiography.

RESULTS

Four bad split occurrences were observed including three patients in the group which impacted mandibular third molars were presented and one patient in the group without impacted mandibular third molars. The incidence of bad fracture in the exposed group was 3.7 times more than the unexposed group. The incidence of the bad fracture in exposed group was 3.7 times more than unexposed group. The chance of fractures in females was 1.7 times higher than males. With one year addition to the patient's age, chance of fracture increased 0.985 times more.

CONCLUSION

Overall incidence of bad split fracture in presence of mandibular third molars in females and at older ages increased during BSSO. The extraction of impacted mandibular third molars, six months before the BSSO is recommended to prevent the bad split incidence during the operation.

Risk factors for bad splits during sagittal split ramus osteotomy: a retrospective study of 964 cases

To identify the potential risk factors for bad splits, we calculated the incidence of bad splits from 484 patients with 964 cases of sagittal split ramus osteotomy (SSRO) and investigated the association between the occurrence of bad splits and risk factors such as gender, patients' age, class of occlusion, unimaxillary or bimaxillary surgery, presence of the lower third molar, thickness of the ascending ramus, and the distance from the mandibular canal to the buccal cortical bone. The results showed that 40 sides (4.149%) with bad splits occurred in 36 patients (7.438%). The mean (SD) gap width from the canal to the buccal cortex for the bad split group, at 4.02 (1.20)mm, was narrower (p=0.003; OR=0.689; 95% CI=0.538 to 0.882) than the normal split group 4.80 (1.72)mm. On the contrary, no statistical significance (p>0.05) was detected between the patients with bad splits and those with normal splits for the other factors. In conclusion, SSRO patients with narrower distances from the mandibular canal to the buccal cortex were more prone to bad splits. More attention should be paid to patients with this risk factor during future surgeries.

Importance in the occurrence rate of shortest buccal bone marrow distance (<1 mm) for sagittal split ramus osteotomy

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 < 1 mm). With an SBM value < 1 mm, we defined a high occurrence rate of postoperative neurosensory abnormality or unfavorable split.

RESULTS

The Class III patients had the smallest SBM value (1.31-1.75 mm) whereas the Class II patients had the largest SBM value (1.57-2.09 mm). For the Class III patients, the highest and lowest occurrence rates of SBM were 56.5% and 43.5% respectively. For the Class II patients, the highest and lowest occurrence rates of SBM were 37.1% and 17.7% respectively. The patients with Class III malocclusion had higher occurrence rates of SBM than the patients with Class II malocclusion.

CONCLUSION

Class III had a significantly higher occurrence of probability (SBM < 1 mm) than Class II. Therefore, patients with Class III were more likely to experience postoperative neurosensory abnormalities and unfavorable split than patients with Class II.

Preventing hypoesthesia after a buccal plate fracture in a sagittal split procedure: A technical note

If during a sagittal split osteotomy a buccal plate fracture occurs, it inevitably results in a time-consuming procedure with, in many cases, hypoesthesia of the mental region as a consequence of manipulation of the inferior alveolar nerve. We would like to present a novel technique to solve a (threatening) buccal plate fracture that is quick and easy to perform, and has thus far not resulted in hypoesthesia.

Neurosensory Disturbances After Bilateral Sagittal Split Osteotomy Using Piezoelectric Surgery: A Systematic Review

PURPOSE

The objective of the present systematic review was to test the hypothesis of no difference in neurosensory disturbances (NSDs) after bilateral sagittal split osteotomy (BSSO) with piezoelectric surgery compared with conventional techniques.

MATERIALS AND METHODS

A PubMed (Medline), Embase Library, and Cochrane Library search in combination with a manual search of relevant journals was conducted from January 2000 to November 2017. Randomized controlled trials and controlled trials in humans were considered. Primary outcome measures (assessment of neuro-sensitivity by subjective and objective evaluations) and secondary outcome measures (NSD risk factors, patient-reported outcome measures, complications, operating time, and intraoperative bleeding) were considered.

RESULTS

The search provided 241 studies of which 5 eligible studies were included. Meta-analysis was not possible because of considerable heterogeneity. Two studies were characterized by a moderate risk of bias and 3 were characterized by a high risk of bias. Piezoelectric surgery substantially decreased NSDs as evaluated by subjective tests. NSD after BSSO varied from 1.8 to 23.0% with piezoelectric surgery and from 7.3 to 52.0% with conventional techniques after 2 to 12 months. Furthermore, piezoelectric surgery seemed to considerably decrease the frequency of intraoperative bleeding in bimaxillary procedures and decrease the risk of an unfavorable split of the mandible and macroscopic damage of the inferior alveolar nerve.

CONCLUSIONS

The hypothesis of no difference in NSD after BSSO with piezoelectric surgery compared with conventional techniques could be neither confirmed nor rejected owing to insufficient knowledge. However, piezoelectric surgery seems to decrease the risk of NSDs after BSSO compared with conventional techniques. Long-term randomized controlled trials comparing the 2 treatment modalities by standardized subjective and objective electrophysiologic tests are needed before one treatment modality can be considered superior to another.

An In Vitro Comparison Study of the Use of a Drill or a Saw in the Hunsuck-Dal Pont Modification of the Obwegeser Sagittal Split Osteotomy in Pig Mandibles

PURPOSE

Fracture lines in unfavorable locations are referred to as "bad splits" in a mandibular sagittal split osteotomy (SSO). Several modifications of the technique by Obwegeser have been introduced to minimize this risk. This in vitro study was performed to determine whether the shape of the osteotomy cut affects the torque and the fracture pattern of an SSO in pig mandibles.

MATERIALS AND METHODS

In a split-mouth model, 16 mandibles were split according to the Hunsuck-Dal Pont modification of the Obwegeser technique. Using an oscillating saw, sharp-edged osteotomies were created on one side of the mandible and round-edged osteotomies were created on the contralateral side using a Lindemann bur. Torque forces were measured during the splitting, and the lingual fracture pattern of each split was classified.

RESULTS

Torque forces were significantly (P < .05 by paired t test) decreased by 0.77 N-m (15.6%) when a saw was used for the osteotomy. In the 2 groups, fractures were produced along the mandibular canal. The mandible was more often completely fractured, including the lower mandibular border, when the fracture was created with an oscillating saw (P = .06 by Pearson χ² test). No correlation was found between the torque used and the fracture pattern.

CONCLUSION

Compared with round-edged osteotomies, sharp-edged osteotomies in pig mandibles facilitated the Hunsuck-Dal Pont modification of the Obwegeser sagittal splitting procedure and produced predictable results with decreased torque.

Complications associated with orthognathic surgery

While most patients undergo orthognathic surgery for aesthetic purposes, aesthetic improvements are most often followed by postoperative functional complications. Therefore, patients must carefully decide whether their purpose of undergoing orthognathic surgery lies on the aesthetic side or the functional side. There is a wide variety of complications associated with orthognathic surgery. There should be a clear distinction between malpractice and complications. Complications can be resolved without any serious problems if the cause is detected early and adequate treatment provided. Oral and maxillofacial surgeons must have a full understanding of the types, causes, and treatment of complications, and should deliver this information to patients who develop these complications.