Risk factors for common complications associated with bilateral sagittal split osteotomy: A literature review and meta-analysis

Investigation of the efficacy of two different laser types in the treatment of lower lip paresthesia after sagittal split ramus osteotomy

Orthognathic surgery involves invasive and major surgical procedures commonly used to correct maxillofacial deformities. Bilateral sagittal split ramus osteotomy (BSSO) is often used to treat dentofacial anomalies related to the mandible, but it can result in various complications, the most common of which is inferior alveolar nerve damage. Nerve damage-induced paresthesia of the lower lip significantly affects patient comfort. Medical treatments such as steroids and vitamin B, low-level laser therapy (LLLT), and platelet-rich fibrin (PRF) can be used as supportive therapies for nerve regeneration after damage. This study aimed to investigate the effectiveness of two different types of lasers in treating lower lip paresthesia after BSSO. This clinical trial was a controlled, single-center, prospective, single-blind, randomized study. Thirty patients were included in the study and randomly assigned to three groups: Group I (laser GRR, n = 10) received transcutaneous and transmucosal GRR laser treatment, Group II (Epic10 laser, n = 10) received transmucosal and transcutaneous Epic10 laser treatment, and Group III (vitamin B, n = 10) received B-complex vitamin tablets orally once a day. Two-point and brush tests were performed six times at specific intervals, and a visual analog scale was used to evaluate pain and sensitivity. Both vitamin B and laser therapies accelerated nerve regeneration. The contribution of the laser groups to the healing rate was better than that of the vitamin B group. Although there was no statistically significant difference between the two laser groups, clinical observations indicated better results in the GRR laser group.

Successful rehabilitation after multiple severe complications following orthognathic surgery: a case report

BACKGROUND

Complications of orthognathic surgery are quite rare, but they cause suffering in affected individuals. The range of complications is broad and includes both hard and soft tissue.

CASE PRESENTATION

We here present a case of a fully healthy woman without signs of impaired healing capacity. The patient underwent bimaxillary orthognathic surgery and experienced multiple complications both peri- and post-operatively. During the post operative period, the patient also suffered from soft tissue complications after an orthopaedic injury. Therefore, we referred the patient to her general practitioner for further medical investigation. We also present the result after restorative surgery and endodontic and prosthodontic treatment resulting in a successful rehabilitation.

CONCLUSION

This case report clearly shows the need for a good collaboration between different odontological and medical fields to achieve a good and predictable result. In situations where normal healing processes do not occur, in-depth analysis must be carried out.

HIGHLIGHTS

Orthognathic surgery affects soft and hard tissue which can result in adverse healing and complications. It is of great importance to follow up performed surgery to see late complications. Be restrictive with early re-operations when there are signs of necrosis. Always use a multidisciplinary approach when handling complications after surgery.

Does osteotomizing the lower border of the mandible affect the lingual split pattern in a sagittal split ramus osteotomy?

AIM

The purpose of this study was to evaluate the effect of adding a fourth osteotomy at the lower border of the mandible on the lingual cortical fracture pattern in bilateral sagittal split ramus osteotomies.

PATIENTS AND METHODS

The sample of the study consisted of 20 patients (12 male and 8 female, with a mean age of 26.79 ± 7.12 years) with mandibular deformities who needed bilateral sagittal split ramus osteotomy. One side underwent a traditional sagittal split ramus osteotomy, and the procedure was modified on the other side by adding a 1 cm horizontal osteotomy at the lower border of the mandible, just distal to the caudal end of the vertical buccal osteotomy cut. A 3D CBCT was used to identify the split pattern.

RESULTS

In the total sample, 40% of the lingual splits ran vertically toward the lower border of the mandible (LSS1), 20% of the splits passed horizontally to the posterior border of the mandible (LSS2), 32.5% of the splits took place along the inferior alveolar canal (LSS3), and 7.5% of the splits were unfavourable fractures (LSS4). On the inferior border osteotomy sides, the distribution of LSS1, LSS2, LSS3, and LSS4 was 10 (25%), 6 (15%), 4 (10%), and 0 (00), respectively. Their distribution on the sides without inferior border osteotomy was 6 (15%), 8 (20%), 13 (32.5%), and 3 (7.5%), respectively. Statistical analysis revealed a significant difference between the two groups (p < 0.05).

CONCLUSION

Inferior border osteotomy tends to direct the lingual split fracture line toward the lower and posterior borders of the mandible and minimizes bad splits; however, further studies are needed to confirm our findings.

Evaluation of the Lingual Splitting Patterns and the Lateral Bone Cut Ends Following Mandibular Bilateral Sagittal Split Osteotomy Using Cone Beam Computed Tomography (CBCT)

The bilateral sagittal split osteotomy (BSSO) is the most popular orthognathic procedure performed by maxillofacial surgeons to treat skeletal class II and class III and to correct mandibular asymmetries. The study aimed to evaluate the lingual splitting patterns and lateral bone cut end (LBCE) in bilateral sagittal split osteotomy (BSSO) and their relation with the ramal thickness and the presence of impacted third molars using cone beam computed tomography (CBCT). This prospective observational study included patients with mandibular prognathism who were treated with BSSO with or without Le Fort I osteotomy. Cone beam computed tomography was used to measure the ramal thickness preoperatively and to evaluate the LBCE, and the lingual splitting patterns postoperatively. Twenty-one patients (42 sides) were included in this study. The most commonly observed lingual splitting pattern was type III (47.6%), while the most common LBCE was type B (59.5%). The bad split was encountered 8 times on 42 sides (16.7%). A nonsignificant relationship between the ramal thickness and bad splitting was observed ( P =0.901). Impacted third molars were present in 16 of the 42 sides (38.1%) and had no significant effect on the occurrence of bad splitting ( P =0.063). Type III lingual splitting pattern and type B LBCE were the most commonly observed patterns. No direct association was observed concerning the presence of impacted mandibular third molars and the thickness of the ramus with the occurrence of bad splitting.

Readmission after orthognathic surgery

OBJECTIVE

To evaluate the readmission rate after orthognathic surgery and identify associated risk factors.

STUDY DESIGN

Retrospective analysis of patients who underwent orthognathic surgery and had an unexpected hospital admission, with or without return to the operating room (OR), within the first postoperative year. Study variables included sex, age, American Society of Anesthesiologists (ASA) status, type of surgery, concomitant third molar extraction, concomitant genioplasty, duration of surgery, first assistant experience, and duration of hospitalization. Bivariate associations were calculated between variables and readmission status. Chi-square and Fisher's Exact tests were used to compare categorical variables, and a 2-sample t test was used to compare continuous variables.

RESULTS

There were 701 patients included in the study. The readmission rate was 9.70%. Twelve patients were managed non-surgically, and 56 patients required an OR procedure. The most common reason for readmission without return to the OR was an infection, and for reoperation was hardware removal. Age, sex, type of surgery, third molar extraction, genioplasty, duration of surgery, and experience of first assistant were not found to be predictors for readmission.

CONCLUSIONS

Only ASA classification and duration of initial hospitalization were significant risk factors for readmission of patients within the first postoperative year after orthognathic surgery.

Risk factors for lower border notching after bilateral mandibular sagittal ramus advancement: three-dimensional evaluation

Bilateral sagittal split osteotomy (BSSO) mandibular advancement can cause mandibular lower border notching (MLBN). The objective of this study was to calculate the incidence of MLBN and identify risk factors. This single-centre, retrospective study was performed between January 2018 and November 2020, in the Maxillofacial Surgery Department, Centre Hospitalier Universitaire, Caen. Patients who underwent BSSO advancement and had cone beam computed tomography (CBCT) scans obtained preoperatively, immediately postoperative (within 1 week), and late postoperative (≥1 year) were included. Measurements were made on the CBCT images. A total of 113 patients (226 operated sides) were enrolled. Mean age at the time of surgery was 17 years; 66.4% of patients were female and 33.6% were male. MLBN was observed on 35 operated sides (15.5% of sides). Advanced age (P = 0.002) and the degree of mandibular advancement (P = 0.008) were determined to be risk factors for developing MLBN. Sex, the operated side, third molar removal, and genioplasty were not associated with an increased occurrence of MLBN. Older patient age at the time of surgery and the requirement for a large advancement should be taken into consideration by the surgeon in order to reduce the risk of MLBN by using a modified BSSO procedure or bone grafting.

Biomechanical Effects of Different Miniplate Thicknesses and Fixation Methods Applied in BSSO Surgery Under Two Occlusal Conditions

Purpose

Finite element analysis (FEA) was used to evaluate the effects of different thicknesses, numbers, and positions of the miniplate applied in bilateral sagittal split osteotomy (BSSO) under two occlusal conditions.

Methods

An FEA model of the mandibles was constructed and combined with different thicknesses (0.6 or 1 mm), number (one or two), positions (upper or lower) of a miniplate and was divided into six models. In addition, external forces were applied to the muscles to simulate the intercuspal position (ICP) and right unilateral molar clench. This study used the reaction force of the temporomandibular joints and the stress of the mandible as observation indexes.

Results

The results of this study show that, under ICP, the 0.6 mm lower model generated greater TMJ force reaction compared to the 0.6 mm upper model. The same trend was seen in the 1 mm lower model compared to the 1 mm upper model. Regarding the stress of the bone on the screw-implanted sites, under ICP, screw 10 showed greater stress than screw 2, and screw 11 showed greater stress than screw 3. The stress values of the miniplates showed, under ICP, point 1-c was greater than point 3-c, and point 1-b was greater than point 3-b.

Conclusion

In the case of BSSO mandibular advancement surgery, implanting the miniplate at the upper position can reduce the force on the TMJ and the stress on the distal segment of the mandible. The miniplate can also resist the tensile stress more effectively. In addition, implanting two miniplates with thinner sizes may be an alternative in clinical practice.

Titanium or Biodegradable Osteosynthesis in Maxillofacial Surgery? In Vitro and In Vivo Performances

Osteosynthesis systems are used to fixate bone segments in maxillofacial surgery. Titanium osteosynthesis systems are currently the gold standard. However, the disadvantages result in symptomatic removal in up to 40% of cases. Biodegradable osteosynthesis systems, composed of degradable polymers, could reduce the need for removal of osteosynthesis systems while avoiding the aforementioned disadvantages of titanium osteosyntheses. However, disadvantages of biodegradable systems include decreased mechanical properties and possible foreign body reactions. In this review, the literature that focused on the in vitro and in vivo performances of biodegradable and titanium osteosyntheses is discussed. The focus was on factors underlying the favorable clinical outcome of osteosyntheses, including the degradation characteristics of biodegradable osteosyntheses and the host response they elicit. Furthermore, recommendations for clinical usage and future research are given. Based on the available (clinical) evidence, biodegradable copolymeric osteosyntheses are a viable alternative to titanium osteosyntheses when applied to treat maxillofacial trauma, with similar efficacy and significantly lower symptomatic osteosynthesis removal. For orthognathic surgery, biodegradable copolymeric osteosyntheses are a valid alternative to titanium osteosyntheses, but a longer operation time is needed. An osteosynthesis system composed of an amorphous copolymer, preferably using ultrasound welding with well-contoured shapes and sufficient mechanical properties, has the greatest potential as a biocompatible biodegradable copolymeric osteosynthesis system. Future research should focus on surface modifications (e.g., nanogel coatings) and novel biodegradable materials (e.g., magnesium alloys and silk) to address the disadvantages of current osteosynthesis systems.

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.

Is orthognathic surgery indicated for wind instrument players? A multiple case study

Introduction For the ambitious wind instrument player with severe malocclusion, the decision to undergo orthognathic surgery can be difficult.Aim To qualitatively explore and reveal key aspects of considerations for and outcomes of orthognathic surgery by interviewing a group of advanced and professional wind instrumentalists.Materials and methods One investigator, using a standardised questionnaire, interviewed seven cases. The interviews were analysed by two investigators who are knowledgeable about embouchure.Outcomes An ideal jaw relationship is not a prerequisite to achieving a professional career in music. Complete embouchure loss after surgery can be experienced due to changes in the position of incisors, lip relationship and tongue position relative to the shape of the oral cavity and as a result of neurosensory changes. Neurosensory recovery and 'wind instrument rehabilitation' takes at least six months, which was achieved in three out of five cases. The following temporary or permanent difficulties during playing after surgery were reported: onset of notes, high notes, leaps and intervals, and stable and well-tuned sound.Conclusion In view of the risks involved, orthognathic surgery in wind instrumentalists should only be considered when there is an (oral) health indication.

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.

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.

Intraoperative removal of third molars does not affect the postoperative infections after BSSO - Randomized controlled trial

The goal of this study was to evaluate the incidence of postoperative wound infection and timing of mandibular third molar removal in bilateral sagittal split osteotomy (BSSO). This wis a prospective, single-blinded, randomized, split-mouth clinical trial. All patients were divided into two groups: Group I, where pre-operative removal of the third molars were done 6 months prior to BSSO and Group II, where intra-operative removal of contralateral third molars were done for the same patients during the osteotomy. The primary outcome variable studied was postoperative infection rate and the secondary outcome variable was bad split during BSSO. Among the seventy five patients (150 sites), one site in group II developed infection whereas none of the sites in group I developed infection (p = 1.000). No sites had bad split in both the groups. The results from the present study show that there is no difference between the presence or absence of mandibular third molars on post-operative wound infection following bilateral sagittal split osteotomy, and the authors hence suggest removing third molars during BSSO for patient comfort.

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.

Penetration of inferior alveolar nerve canal increased by bicortical fixation after bilateral sagittal split osteotomy in mandibular prognathism

The purpose of this three-dimensional cone beam computed tomography (CBCT) study was to identify the difference between monocortical fixation (MCF) and bicortical fixation (BCF) in mandibular canal penetration after bilateral sagittal split osteotomy (BSSO) to correct mandibular prognathism, where interosseous fixation was done by BCF or MCF. CBCT was performed 1 week postoperatively and Dolphin 3D software was used to assess direct penetration of the mandibular canal by either type of screw. The primary outcome variable was the presence or absence of mandibular canal penetration and was categorized as a binary coded variable. The BCF and MCF groups were compared by χ² test, and the odds ratio for canal penetration was estimated. Multiple logistic regression was performed to identify factors related to canal penetration. A total of 118 patients were included. The MCF group had only 6% canal penetrations (3/50 patients) and the BCF group had 58.8% canal penetrations (40/68 patients). The regression model showed that BCF was the only factor causing mandibular canal penetration, with an adjusted odds ratio of 52.5. Awareness of the increased risk of canal penetration with BCF and potential nerve injury might influence case selection.

Position of the mandibular canal before and after bilateral sagittal split ramus osteotomy: a cone beam computed tomographic study

The aim of this study was to evaluate the position of the mandibular canal (MC) before and after bilateral sagittal split ramus osteotomy (BSSRO) using cone-beam computed tomography (CT), and to compare the position of the MC in Class II and Class III patients in the preoperative period. Patients were divided into two groups: Class II (n = 38) and Class III (n = 41). Measurements of the superior, inferior, buccal, and lingual distances of the MC in relation to the cortical bone were taken at three levels in the proximal segment of the mandible. Results were analysed using the Kruskal-Wallis test (p < 0.05). In the Class II group the superior distance of the MC at levels 2 and 3, and the inferior distance at level 3 significantly decreased after BSSRO. In the Class III group, no significant differences were found at any level, and the inferior distances at all levels were smaller preoperatively than those in the Class II group. In the Class II group the position of the MC altered in relation to superior and inferior cortical bone after BSSRO. However, the position of the MC remained stable in the Class III group. Our results also suggest a deeper cut in inferior cortical bone in Class III patients.

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.

Comparison of bicortical, miniplate and hybrid fixation techniques in mandibular advancement and counterclockwise rotation: A finite element analysis study

OBJECTIVE

This study aims to evaluate biomechanical stability and stress distribution of five different fixation types with finite element analysis using 10-mm advancement with or without counterclockwise rotation of the mandible.

MATERIALS AND METHODS

After sagittal split osteotomy, 10-mm advancement was performed in the first group and 10-mm advancement and 10-degree counterclockwise rotation were performed in the second group. One miniplate (M-1), two-miniplate (M-2), one miniplate and a bicortical screw (H), l-shaped bicortical screw (B-1), and inverted l-shaped bicortical screw (B-2) systems were placed. Totally, 120 N force was applied to the models at a 45-degree angle from the lower edge of the symphysis.

RESULTS

The highest values on fixation were seen with miniplate, while the mean values were obtained with bicortical screw system. The highest values on bone were achieved using bicortical screws. One miniplate (M-1) showed both the highest and mean displacement. The highest values in counterclockwise-rotated models increased in all parameters, compared to non-rotated models.

CONCLUSION

In cases in which passive alignment between segments and adequate bone contact are ensured, inverted l-shaped bicortical screw, two-miniplate, or hybrid systems are recommended.

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.

Effectiveness of low-level laser therapy on recovery from neurosensory disturbance after sagittal split ramus osteotomy: a systematic review and meta-analysis

Background

Orthognathic surgery such as bilateral sagittal split ramus osteotomy (BSSRO) for the treatment of mandibular deformities is one of the most common procedures in maxillofacial operations that may lead to neurosensory disturbance. In this study, we aimed to evaluate the effectiveness of low-level laser therapy (LLLT) on augmenting recovery of neurosensory disturbance of inferior alveolar nerve (IAN) in patients who underwent BSSRO surgery.

Methods

A comprehensive literature search was conducted by two independent authors in PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), Scopus, Embase, and Google Scholar electronic databases. Besides, a manual search of all textbooks and relevant articles were conducted. Searches took place in August 2020 and were limited to published and peer-reviewed articles from 2000 to 2020. All analysis was performed using the comprehensive meta-analysis (CMA) and the STATA MP (version:16) software. The weighted mean difference (WMD) using the inverse variance method and the standard mean difference (SMD) was considered for continuous variables.

Results

Seventy-four papers were retrieved after removing duplicate studies and finally, eight studies were assessed for qualitative synthesis and five for meta-analysis. Totally, 94 patients were included in the meta-analysis. Based on the meta-analysis, it was shown that LLLT was not effective in a short interval (0 to 48 h) after surgery, but in a period of more than 1 month after surgery, the positive results of treatment can be observed strikingly. Also, LLLT side/group showed no significant difference in some aspects of neurosensory recovery such as thermal sensation compared to the placebo side/group.

Conclusions

The meta-analysis of randomized controlled trials revealed that LLLT generally improves IAN sensory disturbance caused by BSSRO. Further high-quality clinical trials with longer follow-up periods and larger sample sizes are recommended.

Complications or rather side effects? Quantification of patient satisfaction and complications after orthognathic surgery-a retrospective, cross-sectional long-term analysis

OBJECTIVES

The aim of this clinical analysis was to evaluate intraoperative and early postoperative complications as well as late findings and the overall patient satisfaction following orthognathic surgery.

MATERIALS AND METHODS

In a retrospective, cross-sectional study, 119 patients after orthognathic surgery were included. Surgical approaches were single bilateral sagittal split osteotomy (BSSO (n = 52)), single LeFort-I osteotomy (n = 5) and bimaxillary osteotomy (LeFort-I + BSSO (n = 62)). Intraoperative and early (0-4 weeks postoperative) complications were investigated retrospectively (n = 119), whereas late findings and quality of life were assessed via clinical follow-up and survey (mean: 59 months postoperative) on 48 patients.

RESULTS

Bad split (n = 4/114) was the most common intraoperative complication followed by one case of severe bleeding. Regarding early postoperative complications, temporary damage of the inferior alveolar nerve after BSSO was most common (n = 33/114), followed by facial nerve dysfunction (n = 3), failed osteosynthesis (n = 2) and one case of postoperative dyspnoea. Permanent hypaesthesia of the lower lip was the most prevalent (n = 28/45^{(BSSO and LeFort-I + BSSO)}) late finding with varying extent, followed by temporomandibular dysfunction (TMD) (n = 25/48). Skeletal relapse mostly occurred after class II treatment, followed by class III, posterior crossbite and open bite. Overall, the surgery improved the patients' self-perception (85.4%), with 60.4% of patients opting for surgery again.

CONCLUSIONS

Long-term complications after orthognathic surgery occurred more frequently than commonly described in the literature, and analyses of the quality of life show the need for more comprehensive preoperative patient education.

CLINICAL RELEVANCE

Hypaesthesia of the lower lip presented less as complication but rather as side effect following BSSO. As orthognathic surgery is mostly elective, preoperative patient education is of pivotal importance and should include proactive risk stratification.

Stability of fixation methods in large mandibular advancements after sagittal split ramus osteotomy: an in vitro biomechanical study

Sagittal split ramus osteotomy (SSRO) with large mandibular advancements is a common surgical procedure and could be indicated for patients with sleep apnoea. As a large variety of fixation methods is used for the stabilisation of SSRO, a biomechanical test model was used to analyse which fixation technique was most stable. For this in vitro study, 80 polyurethane hemimandibles with a prefabricated SSRO were used as substrates. Loads in Newtons were recorded at displacements of the mandibular incisive edge at 1mm, 3mm and 5mm. The samples were divided into two groups: mandibular advancements of 10mm and 15mm. In both groups, four fixation techniques were used: (A) one four-hole miniplate; (B) two four-hole miniplates; (C) one four-hole miniplate plus one bicortical screw; and (D) three bicortical screws in an inverted-L arrangement. In group 1, three bicortical screws resulted in the best stability, and in group 2, two miniplates resulted in the best stability. The use of two miniplates did not show significant differences between both groups. Other fixation methods showed more stability with 10mm advancements. This study therefore suggests that in SSRO with advancements exceeding 10mm, the use of two miniplates is the optimal means of providing rigid fixation.

Antibiotic prophylaxis in oral and maxillofacial surgery: a systematic review

Surgical site infections are a complication of oral and maxillofacial procedures, with the potential for significant morbidity and mortality. Use of preoperative, perioperative, and postoperative antibiotic prophylaxis to reduce the incidence of surgical site infections must be balanced with considerations of a patients' risk of antibiotic-related adverse events. This review aimed to provide evidence-based recommendations for antibiotic prophylaxis. Searches were conducted using MEDLINE, the Cochrane Library, EMBASE, and PUBMED for maxillofacial procedures including: treatment of dental abscesses, extractions, implants, trauma, temporomandibular joints, orthognathics, malignant and benign tumour removal, and bone grafting, limited to articles published since 2000. A total of 98 out of 280 retrieved papers were included in the final analysis. Systematic reviews were assessed using AMSTAR criteria. Randomised controlled trials were assessed for bias using Cochrane Collaborative tools. The overall quality of evidence was assessed using GRADE. Prophylactic antibiotic use is recommended in surgical extractions of third molars, comminuted mandibular fractures, temporomandibular joint replacements, clean-contaminated tumour removal, and complex implants. Prophylactic antibiotic use is not routinely recommended in fractures of the upper or midface facial thirds. Further research is required to provide recommendations in orthognathic, cleft lip, palate, temporomandibular joint surgery, and maxillofacial surgical procedures in medically-compromised patients.

Long-term neurosensory disturbances after modified sagittal split osteotomy

We have investigated the long-term incidence of neurosensory disturbances after modified bilateral sagittal split osteotomy, and identified associated risk factors. We prospectively studied 376 patients, and their self-reported neurosensory disturbances were evaluated six months, and one, two, and three years postoperatively. The correlations between the following risk factors and neurosensory disturbances were investigated using univariate analysis and stepwise multivariate analysis: age at operation, sex, type of movement (advancement, setback, or rotation), concurrent genioplasty, type of detachment, iliac crest bone graft, and use of dicalcium phosphate synthetic bone graft. Probabilities of less than 0.05 were accepted as significant. Three years postoperatively, 57 patients (15%) reported altered sensation of the lower lip or chin. Older age correlated significantly with neurosensory disturbances (p<0.0001). Greater mandibular advancement correlated with postoperative "positive" neurosensory phenomena (right side p=0.08; left side p=0.03). Intraoperative surgical manipulation of the left inferior alveolar nerve was significantly associated with postoperative hypoaesthesia (p=0.014). Older age at surgery, extensive mandibular advancement, and surgical manipulation of the left inferior alveolar nerve, were associated with long-term neurosensory disturbances after modified bilateral sagittal split osteotomy. The modified operation seems to safeguard the inferior alveolar nerve from transection, without causing damage to other nerves.

What factors affect the attachment of the inferior alveolar nerve to the buccal plate following sagittal split osteotomy?

PURPOSE

This study aimed to assess the factors that can possibly affect the positioning of the inferior alveolar nerve (IAN) in the proximal or distal segment following sagittal split osteotomy (SSO).

MATERIALS AND METHODS

This was a prospective cohort study. The patients were assigned according to the position of the IAN: the IAN was attached to the buccal plate in group 1 (27 SSOs), while it was in the distal segment in group 2 (83 SSOs).

RESULTS

The mean of the buccolingual thickness of the proximal segment at the vertical cut of the osteotomy (BLTP) was 5.0 ± 0.62 mm in group 1 and 4.16 ± 0.72 mm in group 2. The mean of the distance between the IAN and the external cortical bone at the distal of the second molar before the osteotomy (IANB) was 0.5 ± 0.24 mm in group 1 and 1.24 ± 0.45 mm in group 2. There were significant differences for the mean BLTP and IANB between the two groups (P = 0.001).

CONCLUSION

It seems that the thickness of the buccal plate of the proximal segment, the distance from the IAN to the external cortical bone, the osteotomy technique, and the presence or absence of impacted third molars may be associated with the positioning of the IAN following SSO.

Density of the mandibular ramus (cancellous:cortical bone volume ratio) as a predictor of the lingual fracture pattern in bilateral sagittal split osteotomy

The aim of this retrospective cohort study was to evaluate the relative amount of cancellous bone in the mandibular ramus as a predictor of lingual fracture patterns after bilateral sagittal split osteotomy (BSSO). The study including 78 consecutive patients (156 osteotomy sites). In preoperative cone-beam computed tomographic (CT) scans, the volumes of cancellous and cortical bone in the BSSO surgical field were estimated. Patients were divided into two groups based on the cancellous:cortical bone ratio. We studied postoperative cone-beam CT scans for lingual fracture lines and subcategorised them according to the lingual split scale (LSS). Generalised linear mixed models (GLMM) were estimated to evaluate the association between the cancellous:cortical bone ratio and the lingual fracture pattern. There was a significant association between the cancellous:cortical bone ratio of the mandibular angle and the lingual fracture pattern after BSSO. Mandibular angles with a relatively small amount of cancellous bone showed significantly more LSS3 fracture lines (OR=1.990, 95%CI 1.043 to 3.796, p=0.043). These mandibular angles also showed more unfavourable fractures (LSS4), although this was not significant (OR=2.352, 95%CI 0.748 to 7.392, p=0.143). The relative amount of cancellous bone in the mandibular angle is significantly associated with the lingual fracture line after BSSO.

Effect of photobiomodulation on recovery from neurosensory disturbances after sagittal split ramus osteotomy: a triple-blind randomised controlled trial

We have investigated the effect of photobiomodulation on the recovery of neurosensory function of the lip and chin after bilateral sagittal split osteotomy (BSSO). Laser irradiation was applied with a GaAs diode laser (continuous wave 980nm wavelength, power 100mW, and energy density 12J/cm²). It was maintained within a 0.5cm² area in a total of 12 points for 60seconds at each visit on each point. Unilateral extraoral contact photobiomodulation treatment was applied the day before operation and then on days 1, 3, 7, 14, 21, and 28 postoperatively. One side of the mandible was the intervention side and the other the control side. On the control side, the laser probe was turned off and placed on the chosen area. Neurosensory evaluations were made before and immediately after operation, and 30 days and 60 days postoperatively. Twenty-five patients were screened, and 18 who met the inclusion criteria were included in the study; 14 were women and the mean (SD) age was 23 (5) years. Analysis of the visual analogue scales for general sensibility, pain discrimination, directional discrimination, and 2-point discrimination showed a significant difference between the intervention and control sides after 30 days (p=0.0011, 0.0034, 0.0023, and 0.0160, respectively). The difference was also significant after 60 days (p=0.0001, 0.0002, 0.0003, and 0.0010, respectively). The thermal discrimination rate was significantly higher in the laser group than the control group 30 days after surgery (p=0.002), but after 60 days the difference was not significant (p=1.000). We found no side effects from the laser radiation during the two-month follow up. The results suggest that photobiomodulation accelerated the patients' improvement from neurosensory disturbance after BSSO.

Complications associated with orthognathic surgery: A retrospective study of 485 cases

PURPOSE

To identify the most prevalent types of complications associated with orthognathic surgery and its possible risk factors.

METHODS

This study was a retrospective investigation of records of 485 patients who underwent orthognathic surgery between 2008 and 2014 at the Oral and Maxillofacial Surgery Service at the Federal University of Paraná, Curitiba, Brazil. Types of complications were recorded. Independent variables such as sex, age, duration of surgery and hospitalization, number of surgeries, surgical site, and types of osteotomy performed were evaluated. Complications were also evaluated based on the treatment according to the Clavien-Dindo Classification. Data were submitted to statistical analysis with a significance level of 0.05.

RESULTS

A total of 93 complications were reported (19.2%), including postoperative malocclusion, hemorrhage, inferior alveolar nerve injury, bad split, and infection. Complications were more common in men (p = 0.029). The number of complications was higher in surgeries that took more time to perform (p < 0.05) when the entire sample was taken into consideration. The prevalence of complications was related to a higher number of procedures per surgery (p = 0.019). Complications were more frequent in mandibular procedures (p = 0.010), particularly in bilateral sagittal split osteotomies (p < 0.001). Related to treatment, Clavien-Dindo grade I complications were the most frequent (72.04%). There was no association between sex, age, surgery duration, length of hospitalization, or surgical site with complication grades according to the Clavien-Dindo classification (p ≥ 0.05).

CONCLUSION

Postoperative malocclusion, hemorrhage, inferior alveolar nerve injury, bad split and infection are the most prevalent complication in orthognathic surgery. They seem to be related to sex, duration of surgery, number of surgeries, surgical site, and the type of osteotomy performed. With these in mind, it is possible to explain to the patient the different levels of severity of complications related to the surgery.

Age and gender variations in the cone-beam computed tomographic location of mandibular canal: Implications for mandibular sagittal split osteotomy

Background

Mandibular sagittal split osteotomy (MSSO) may incur unfavorable split and sensorineural injuries. Knowledge of the anatomic location of the mandibular canal (MC) and bone thickness in the region of interest for MSSO, and the possible variations by age and gender can assist in avoiding such complications. Purpose: To study the location of the MC and bone thickness in the region of MSSO by cone-beam computed tomography (CBCT) radiographs and to evaluate the possible variations by age and gender in a Jordanian population.

Material and Methods

This retrospective radio-anatomical study examined all CBCT radiographs for patients treated over three years at the University of Jordan Hospital, Amman, Jordan. Distances from the MC to the cortical external surfaces and MC diameter (MCD) were measured by a reliable observer at three predetermined regions for MSSO: region (A) [mandibular foramen area], region (B) [mandibular angle area] and region (C) [directly mesial to the second molar]. Gender and age differences in all measurements were then compared using non-parametric Mann-Whitney U test.

Results

The final study radiographs comprised a total of 202 CBCT belonged to a cohort of 202 subjects; 91 males (45.1%) and 111 (54.9%) females, with mean age (± SD) of 42.94 ± 18.54 years (range 18–90 years). Whereas only the bone thickness superior, buccal and inferior to MC in regions (B) and (C), and MCD in the three regions exhibited significant (p< 0.05) gender differences, all measured distances exhibited statistically significant (p< 0.05) differences between young and adult patients.

Conclusions

The location of MC and bone thickness in the region of MSSO were significantly variable according to age, but exhibited sexual diamorphism only in regions (B) and (C). This fundamental knowledge should be considered during MSSO planning.

Key words:Cone-Beam Computed Tomography, mandibular canal, mandibular sagittal split osteotomy.

Fixation methods in sagittal split ramus osteotomy: a systematic review on in vitro biomechanical assessments

The aim of this systematic review was to assess the stability of rigid internal fixation (RIF) techniques in sagittal split ramus osteotomy (SSRO) based on in vitro biomechanical assessments, with particular interest in large mandibular advancements. In general, RIF methods can be divided into three groups: bicortical screws, miniplates, and a combination of the two. An electronic search of the PubMed, CINAHL, and Embase databases was performed, and studies published between January 2003 and March 2018 were screened for inclusion. Comparative studies with an in vitro experimental design, using biomechanical assessments to measure the stability of RIF methods in SSRO, were included. Of 104 unique studies identified in the initial search, 24 were included. Twenty-two of these 24 studies analyzed an advancement of the mandible of 7mm or less. The use of a single four-hole or six-hole miniplate was less stable than the use of bicortical screws, hybrid techniques, double miniplates, or grid plates. Two studies analyzed advancements of 10mm, for which two miniplates placed in parallel and a grid plate showed most stability. Although there was agreement between studies with regard to results, more biomechanical studies are required to quantify the stability of fixation methods in larger mandibular advancements.

Osteotomy Site Grafting in Bilateral Sagittal Split Surgery With Bioactive Glass S53P4 for Skeletal Stability

In orthognathic surgery, the aim of the treatment is to achieve a good occlusion and a satisfying aesthetic outcome. In large mandibular advancements insufficient healing at the mandibular inferior border may lead to loss of support for the overlaying tissue at the osteotomy site. Augmentation can be performed to improve stability, bone regeneration, and the aesthetic outcome. The purpose of this prospective clinical study was to evaluate the use of a novel material for this indication; granules of the antibacterial, osteoconductive, and slowly resorbing bioactive glass S53P4 as filling material in large mandibular advancement in bilateral sagittal split osteotomies. The authors treated 25 patients who underwent bilateral sagittal split osteotomies due to class II dentoskeletal deformities. The mandibular osteotomy site defects (8-15 mm) were augmented with bioactive glass S53P4. The average clinical follow-up was 33 months and the average radiological follow-up with cone beam computerized tomography was 24 months. The clinical and radiological results were good with regard to healing, bone regeneration, and stability of the osteotomy sites. The recontouring of the inferior mandibular border provided a good soft tissue support followed by an excellent aesthetic outcome in 96% of the osteotomy sites. The occlusion was stable in 88% of the patients. The authors' results show that bioactive glass S53P4 is a safe grafting material for osteotomy site defects in significant mandibular advancements with reliable bone regeneration, providing long-term stability at the osteotomy site and at the inferior mandibular border.

Orthodontic camouflage versus orthodontic-orthognathic surgical treatment in class II malocclusion: a systematic review and meta-analysis

This systematic review was performed to compare dental, skeletal, and aesthetic outcomes between orthodontic camouflage and surgical-orthodontic treatment, in patients with a skeletal class II malocclusion and a retrognathic mandible who have already finished their growth period. A literature search was conducted, and a modified Downs and Black checklist was used to assess methodological quality. The meta-analysis was conducted using the DerSimonian-Laird random-effects method to obtain summary estimates of the standardized mean differences and corresponding 95% confidence intervals. Nine articles were included in the qualitative synthesis and seven in the meta-analysis. The difference between treatments was not statistically significant regarding SNA angle, linear measurement of the lower lip to Ricketts' aesthetic line, convexity of the skeletal profile, or the soft tissue profile excluding the nose. In contrast, surgical-orthodontic treatment was more effective with regard to ANB, SNB, and ML/NSL angles and the soft tissue profile including the nose. Different treatment effects on overjet and overbite were found according to the severity of the initial values. These results should be interpreted with caution, due to the limited number of studies included and because they were non-randomized clinical trials. Further studies with larger sample sizes and similar pre-treatment conditions are needed.

CBCT location of the fusion between the buccal and lingual cortical in the mandibular ramus: importance to sagittal split osteotomy

Background

Mandibular Sagittal Split Osteotomy (MSSO) is a popular technique in orthognathic surgery used both to advance and to retreat the mandible. However, MSSO may incur in important complications, such as bad splits and sensorineural injuries. Knowing the location of the fusion between the buccal and lingual cortical (FBLC) in the mandibular ramus and the bone thickness in the region where osteotomies will be performed is determinant in MSSO planning to avoid complications. The aim of this study was to document and evaluate possible differences between sexes regarding the location of the FBLC in relation to the superior cortical of mandibular foramen (MF) and bone thickness in the region of interest for MSSO in a Brazilian population.

Material and Methods

Eighty five cone-beam Computed Tomography (CBCT) scans were used to perform linear measurements to determine the location of the FBLC. Bone thickness from the mandibular canal (MC) to the cortical external surfaces and the diameter of the MC were measured at three different points: mandibular ramus (A), mandibular angle (B) and mesial of the second molar (C).

Results

The FBLC was located at a mean distance of 8.3 mm from the superior cortical of the MF in males and 8.1 mm in females. There was no difference between males and females regarding the mean bone thickness from the MC to the buccal external surface at all the points investigated (p >>0.05). Bone thickness from the lingual external surface to the MC was bigger among females than males in regions B and C (p<0.05). The diameter of the MC was bigger among males in regions B and C.

Conclusions

Sexual dimorphism regarding mandibular bone thickness but not regarding the location of FBLC was present. This fundamental knowledge may assist to the panning of MSSO.

Key words:Cone-Beam Computed Tomography, mandibular nerve, orthognathic surgery, sagittal split ramus osteotomy.

Are there risk factors for osseous mandibular inferior border defects after bilateral sagittal split osteotomy?

PURPOSE

Bone defects of the inferior mandibular border (osseous inferior border defects) can cause unesthetic postoperative outcomes after bilateral sagittal split osteotomy (BSSO). The aim of this study was to estimate the frequency of osseous inferior border defects after BSSO and to identify risk factors for this complication.

MATERIALS AND METHODS

This retrospective study included consecutive patients who underwent BSSO for mandibular retrognathia. The primary outcome was the presence/absence of osseous inferior border defects. Predictors included the mandibular movement, rotation of the occlusal plane, postoperative proximal segment position, pattern of lingual fracture, occurrence of bad split, and presence of third molars.

RESULTS

The study sample consisted of 200 patients and had a mean follow-up of 13 months. The mean mandibular advancement and rotation was respectively 5.8 mm and 5.4° clockwise. Osseous inferior border defects were present in 7.0% of splits and in 12.5% of patients. Significant risk factors for inferior border defects included increased advancement, increased clockwise rotation, cranial rotation of the proximal segment, and a split originating in the lingual cortex.

CONCLUSION

In conclusion, osseous inferior border defects occur significantly more often in cases with large mandibular advancement, increased clockwise rotation of the occlusal plane, malpositioning of the proximal segment, and a split originating in the lingual cortex.