Functional and radiographic long-term results after bad split in orthognathic surgery

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.

The Unfavourable Split: a novel classification and an 11-year retrospective study looking at alternative methods for management of this well-known complication

An unfavourable split is a well-known complication following a sagittal split osteotomy (SSO) of the mandible. Our aim was to analyse all unfavourable mandibular splits that had occurred when carrying out a SSO with the aim to design a classification which can facilitate management. We carried out a retrospective study analysing all orthognathic surgery from January 2010 until April 2021. Data surrounding unfavourable splits during this period were specifically analysed. Orthognathic surgery during this period was performed by a single OMFS unit with osteotomies performed by a single surgeon and their trainee. The dataset included 311 patients who underwent either a bilateral sagittal split osteotomy (BSSO) or a bimaxillary osteotomy. There were 225 bimaxillary osteotomies and 86 BSSOs. Twenty-one patients had unfavourable splits following their BSSO with a total of 22 out of 622 sagittal split osteotomies over this 11-year period. Bilateral unfavourable splits occurred in one patient. These results correlate to an incidence rate of 6.8% of unfavourable splits following SSO's in an 11-year period. The results reveal common patterns of unfavourable splits to suggest a simple classification based on our results. This can be applied to any unfavourable splits in SSO which then allows the clinician to proceed with surgery and prevent abandonment of the procedure. It is classified as follows: Type 1 fractures where the mandibular condyle is attached to the proximal fragment; Type 2 fractures whereby the mandibular condyle is attached to the tooth-bearing segment; Type 3 fractures are lingual cortex fractures. Each of these fracture types has a specific management protocol, which we recommend is used in all unfavourable splits.

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.

Incidence of condylar resorption after bimaxillary, Lefort I, and mandibular surgery: an overview

The aim of the present overview was to evaluate the outcomes of systematic reviews to determine the incidence of condylar resorption in patients submitted to orthognathic surgery and analyze whether the risk of developing this condition is related to a specific type of surgery. Searches were conducted in the PubMed/MEDLINE, Embase, and Cochrane electronic databases for systematic reviews with quantitative data on condylar resorption due to any type of orthognathic surgery for dentoskeletal deformities published up to May 25, 2019. The AMSTAR 2 and Glenny tools were applied for the quality appraisal. Five systematic reviews were included for analysis. Only one article was considered to have high quality. Among a total of 5128 patients, 12.32% developed condylar resorption. From those patients, 70.1% had double jaw surgery, 23.4% had mandibular surgery alone, and in 6.5% a Lefort I technique was used. Based on these findings, bimaxillary surgery could be considered a risk factor for condylar resorption. However, these results should be interpreted with caution, since other factors, such as pre-operative skeletal deformities, type of movement, and type of fixation, can contribute to the development of this condition. Further studies should consider reporting main cephalometric data, temporomandibular diagnosis, hormonal levels, and tomographic measures before and after the surgery at least every 6 months during the firsts two years to identify accurately risk factors for condylar resorption.

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.

Condylar form alteration on skeletal class II patients that underwent orthognathic surgery: An overview of systematic reviews

Background

Bilateral sagittal split osteotomy (BSSO) is commonly considered as the surgical technique of election for the treatment of skeletal class II with mandibular hypoplasia. After orthognathic surgery, condylar resorption can occur as a surgical relapse, which may affect the temporomandibular joint. Objective: This study aimed to summarise published systematic review that assess if orthognathic surgery with mandibular advancement performed on skeletal class II patients results in condylar form alteration.

Material and Methods

A literature search was performed using the electronic databases PubMed, Web of Science, Cochrane Library, Embase along with several sources of grey literature. Selection Criteria: Inclusion criteria were systematic reviews published until December 2019, of skeletal class II patients aged more than 18 years old that underwent BSSO with mandibular advancement surgery. Data collection: The electronic search identified 37 publications. Four publications fulfilled the inclusion criteria and were included in this meta-analysis. Qualitative assessment of the selected studies was performed using the Assessment of Multiple Systematic Reviews – AMSTAR 2 checklist.

Results

Four systematic reviews were included in this review. Despite its low incidence all studies reported condylar resorption. However, there were methodological limitations in all assessed articles.

Conclusions

The alteration of the condylar form may be a consequence of BSSO with mandibular advancement surgery. Additional high quality prospective research assisted by 3D-imaging technology is needed to allow more definite conclusions.

Key words:Evidence-based orthodontics, TMJ, Class II, mandibular advancement, malocclusion, Angle class II.

Temporomandibular disorders in Class II malocclusion patients after surgical mandibular advancement treatment as compared to non-treated patients

BACKGROUND

Severe malocclusions may cause functional and aesthetic problems and symptoms of temporomandibular disorders (TMD). Studies have investigated association between malocclusions and TMDs and shown controversial findings.

OBJECTIVE

Purpose of this investigation was to examine the prevalence of TMD sub-diagnoses, using Diagnostic Criteria for the TMD (DC/TMD), in patients with Class II malocclusion and retrognathic mandible who had undergone mandibular advancement surgery 4-8 years previously, and to compare their frequencies with non-treated patients with a similar pre-existing condition.

METHODS

Study cohort comprised 151 patients who had orthognathic treatment due to mandibular retrognathia in 2007-2011. Seventy-seven (51%) participated in the study (Group 1). Group 2 comprised 22 patients who were planned for orthognathic treatment but had not started their treatment. Patients filled in the Finnish version of the DC/TMD Symptom Questionnaire and were examined using to the DC/TMD Axis I. DC/TMD Symptom Questionnaire were inquired by phone from 24 of the 74 patients who did not participate in the study.

RESULTS

Results showed that Group 2 had more myalgia (13% vs 50%, P < 0.001) and arthralgia (18% vs 65%, P < 0.001) sub-diagnoses than Group 1. A tendency was noted that Group 2 had more pain-related TMD symptoms than Group 1. No differences were found between Groups 1 and 3 in gender and age distribution or frequency TMD symptoms.

CONCLUSION

Prevalence of especially pain-related TMD diagnoses was higher in Group 2 compared to Group 1, thus indicating a possible beneficial effect of this treatment for TMD.

Condylar resorption in orthognathic patients after mandibular bilateral sagittal split osteotomy: a systematic review

Objective

To systematically search the literature and assess the available evidence regarding the incidence and quantification of condylar resorption following bilateral sagittal split osteotomy (BSSO) of the mandible in orthognathic patients.

Search methods

Electronic database searches of published and unpublished literature were performed. The reference lists of eligible studies were hand searched for additional studies.

Selection criteria

Randomized clinical trials (RCTs), prospective, and retrospective studies with patients of any age that underwent BSSO were included.

Data collection and analysis

Study selection, data extraction, and risk of bias assessment were performed individually and in duplicate.

Results

One RCT, 3 prospective, and 10 retrospective studies were included in this review. The lack of standardized protocols and the high amount of heterogeneity precluded a valid interpretation of the actual results through pooled estimates. There was a substantial consistency among studies, however, that young, female patients with mandibular deficiency and high mandibular plane angle, submitted to surgical counterclockwise rotation of mandibular segments, were more prone to a higher risk for condylar resorption after BSSO. The level of evidence was found to be low given the high/serious risk of bias in all included studies.

Conclusions

Condylar resorption should be taken into account as a potential postsurgical complication after BSSO. However, its incidence and quantification need precautious interpretation owing to the low level of evidence and the high heterogeneity of studies. Additional high-quality prospective research assisted by 3D imaging technology is needed to allow more definitive conclusions.

Registration

Study not registered.

Conflict of interest

None.

Bad splits in bilateral sagittal split osteotomy: systematic review and meta-analysis of reported risk factors

An unfavourable and unanticipated pattern of the bilateral sagittal split osteotomy (BSSO) is generally referred to as a 'bad split'. Patient factors predictive of a bad split reported in the literature are controversial. Suggested risk factors are reviewed in this article. A systematic review was undertaken, yielding a total of 30 studies published between 1971 and 2015 reporting the incidence of bad split and patient age, and/or surgical technique employed, and/or the presence of third molars. These included 22 retrospective cohort studies, six prospective cohort studies, one matched-pair analysis, and one case series. Spearman's rank correlation showed a statistically significant but weak correlation between increasing average age and increasing occurrence of bad splits in 18 studies (ρ=0.229; P<0.01). No comparative studies were found that assessed the incidence of bad split among the different splitting techniques. A meta-analysis pooling the effect sizes of seven cohort studies showed no significant difference in the incidence of bad split between cohorts of patients with third molars present and concomitantly removed during surgery, and patients in whom third molars were removed at least 6 months preoperatively (odds ratio 1.16, 95% confidence interval 0.73-1.85, Z=0.64, P=0.52). In summary, there is no robust evidence to date to show that any risk factor influences the incidence of bad split.

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

An unfavourable and unanticipated pattern of the mandibular sagittal split osteotomy is generally referred to as a 'bad split'. Few restorative techniques to manage the situation have been described. In this article, a classification of reported bad split pattern types is proposed and appropriate salvage procedures to manage the different types of undesired fracture are presented. A systematic review was undertaken, yielding a total of 33 studies published between 1971 and 2015. These reported a total of 458 cases of bad splits among 19,527 sagittal ramus osteotomies in 10,271 patients. The total reported incidence of bad split was 2.3% of sagittal splits. The most frequently encountered were buccal plate fractures of the proximal segment (types 1A-F) and lingual fractures of the distal segment (types 2A and 2B). Coronoid fractures (type 3) and condylar neck fractures (type 4) have seldom been reported. The various types of bad split may require different salvage approaches.

Preoperative, intraoperative, and postoperative complications in orthognathic surgery: a systematic review

Objectives

The aim of this study was to determine whether orthognathic surgery is associated with any complications, and what type of complications may occur.

Materials and methods

Data were obtained using PubMed (MEDLINE), ISI Web of Knowledge, Ovid, Cochrane Library, Embase Library, and an additional manual search. The titles and abstracts of the electronic search results were screened and evaluated by two observers for eligibility according to the inclusion and exclusion criteria.

Results

A total of 1924 articles were identified, and we retained 44 articles for the final analysis. The Prisma diagram flowchart demonstrates our selection scheme. For the purpose of this study, the Cochrane data extraction form was modified. One review author extracted data from the included studies, and the second author checked all of the forms. The hierarchy of evidence classification from the UK NHS Centre for Reviews and Dissemination was used to assess the level of evidence for the retrieved studies.

Conclusions

An evaluation of the obtained studies revealed the existence of a large number of varied complications associated with orthognathic surgery procedures.

Clinical relevance

Oral and maxillofacial surgeons, orthodontists, and the surgical team need to prevent such complications during preoperative, intraoperative, and postoperative periods to increase the safety of orthognathic surgery procedures. This review was registered on http://www.crd.york.ac.uk/PROSPERO as CRD42013004711.

Electronic supplementary material

The online version of this article (doi:10.1007/s00784-015-1452-1) contains supplementary material, which is available to authorized users.

Three-dimensional evaluation of lingual split line after bilateral sagittal split osteotomy in asymmetric prognathism

OBJECTIVES

The aim of this study was to evaluate the pattern of lingual split line when performing a bilateral sagittal split osteotomy (BSSO) for asymmetric prognathism. This was accomplished with the use of cone-beam computed tomography (CBCT) and three-dimensional (3D) software program.

MATERIALS AND METHODS

The study group was comprised of 40 patients (20 males and 20 females) with asymmetric prognathism, who underwent BSSO (80 splits; n=80) from January 2012 through June 2013. We observed the pattern of lingual split line using CBCT data and image analysis program. The deviated side was compared to the contralateral side in each patient. To analyze the contributing factors to the split pattern, we observed the position of the lateral cortical bone cut end and measured the thickness of the ramus that surrounds the mandibular lingula.

RESULTS

The lingual split patterns were classified into. The true "Hunsuck" line was 60.00% (n=48), and the bad split was 7.50% (n=6). Ramal thickness surrounding the lingual was 5.55±1.07 mm (deviated) and 5.66±1.34 mm (contralateral) (P=0.409). The position of the lateral cortical bone cut end was classified into three types: A, lingual; B, inferior; C, buccal. Type A comprised 66.25% (n=53), Type B comprised 22.50% (n=18), and Type C comprised 11.25% (n=9).

CONCLUSION

In asymmetric prognathism patients, there were no differences in the ramal thickness between the deviated side and the contralateral side. Furthermore, no differences were found in the lingual split pattern. The lingual split pattern correlated with the position of the lateral cortical bone cut end. In addition, the 3D-CT reformation was a useful tool for evaluating the surgical results of BSSO of the mandible.

Effect of perioperative buccal fracture of the proximal segment on postoperative stability after sagittal split ramus osteotomy

Objectives

Buccal fracture of the mandibular proximal bone segment during bilateral sagittal split ramus osteotomy (SSRO) reduces the postoperative stability. The primary aim of this study is to evaluate the effect of this type of fracture on bone healing and postoperative stability after mandibular setback surgery.

Materials and Methods

Ten patients who experienced buccal fracture during SSRO for mandibular setback movement were evaluated. We measured the amount of bone generation on a computed tomography scan, using an image analysis program, and compared the buccal fracture side to the opposite side in each patient. To investigate the effect on postoperative stability, we measured the postoperative relapse in lateral cephalograms, immediately following and six months after the surgery. The control group consisted of ten randomly-selected patients having a similar amount of set-back without buccal fracture.

Results

Less bone generation was observed on the buccal fracture side compared with the opposite side (P<0.05). However, there was no significant difference in anterior-posterior postoperative relapse between the group with buccal fracture and the control group. The increased mandibular plane angle and anterior facial height after the surgery in the group with buccal fracture manifested as a postoperative clockwise rotation of the mandible.

Conclusion

Bone generation was delayed compared to the opposite side. However, postoperative stability in the anterior-posterior direction could be maintained with rigid fixation.

Risk factors and prevention of bad splits during sagittal split osteotomy

PURPOSE

One of the operative complications of the sagittal split osteotomy of the mandible is a bad split, which describes an unfavorable or irregular fracture of the mandible in the course of the osteotomy. The purpose of this study is to identify previous studies which reported incidences of bad split occurrence during sagittal split osteotomy and to discuss its mechanisms and risk factors, based on a literature review, in order to minimize their occurrence. A few illustrative cases are also presented.

METHODS

An electronic search was undertaken in January 2011. The titles and abstracts from these results (n = 363) were read for identifying studies which reported incidences of bad split occurrence during sagittal split osteotomy procedures.

RESULTS

Twenty-one studies were identified and assessed. The incidence of bad splits from these studies varied between 0.21% and 22.72%. The buccal plate of the proximal segment and the posterior aspect of the distal segment were the most affected areas.

DISCUSSION

The surgical patient should be evaluated according to age and the presence of unerupted/impacted third molars. Prevention is focused on adequate osteotomy design, eliminating sharp angle where abnormal stress occurs on bony segments, completion of adequate cuts into the retrolingular depression and through the inferior border, and careful separation of the segments. The SSO is an extremely technical and sensitive procedure, and careful attention will probably prevent most unfavorable splits. If a fracture occurs, the fractured segments should be incorporated into the fixation scheme if possible. The occurrence of bad splits cannot always be avoided. When adequately treated the chances of functional success are good.