Perioperative complications following sagittal split osteotomy of the mandible

Three-dimensional computed tomographic evaluation of bilateral sagittal split osteotomy lingual fracture line and le fort I pterygomaxillary separation in orthognathic surgery using cadaver heads: ultrasonic osteotome versus conventional saw

PURPOSE

The purpose of this study was to observe the quality of the fracture line on the lingual side of the mandible after sagittal split osteotomy and the quality of pterygomaxillary separation after Le Fort I osteotomy using the BoneScalpel ultrasonic osteotome.

MATERIALS AND METHODS

Bimaxillary procedures, according to the standard protocol, were performed using 10 fresh cadaver heads. The ultrasonic osteotome was used in the study group, and a reciprocating saw was used in the control group. Three-dimensional reconstructions of postoperative computed tomographic scans were obtained. The lingual ramus fracture pattern and the pterygomaxillary separation pattern were observed, classified, and compared. Postoperative dissections of the skulls were performed to assess the integrity of the infra-alveolar nerve and the descending palatine artery.

RESULTS

No significant differences were found in the cutting time of bone between the BoneScalpel and the sagittal saw. Of the sagittal split osteotomies in the study group, 90% showed a good pattern (vertical pattern of fracture line extending to the inferior border of the mandible running behind the mandibular canal) compared with 50% of the sagittal split osteotomies in the control group. Ideal separation of the pterygoid plates without fractures was observed in 80% of the Le Fort I osteotomies in the study group compared with 50% of the osteotomies in the control group. High-level fractures occurred in 30% of cases in the control group compared with none in the study group. The integrities of the infra-alveolar nerve and the descending palatine artery were preserved in all cases.

CONCLUSION

Use of the ultrasonic BoneScalpel did not require more time than the conventional method. An improved pattern of lingual fracture lines in mandibular sagittal split osteotomy procedures and the pattern of pterygomaxillary separation in Le Fort I osteotomy procedures were observed.

Peri-operative second molar tube failure during orthognathic surgery: two case reports

With improvements in bonding techniques, bracket base design and bond strengths, molar tubes are becoming more popular in orthodontics. Molar tubes make an attractive alternative to conventional banding due to a reduction in clinical bonding time and ease of placement on partially erupted teeth. The use of molar tubes negates the need for orthodontic separation and subsequent cementation of bands, and offers improved periodontal health. Their use on terminal molars, however, should be limited to non-orthognathic cases. This paper presents two cases of peri-operative second molar tube failure during orthognathic surgery. They are presented in the hope that it will highlight the importance of banding the distal terminal molar in orthognathic cases to prevent loss of molar tubes and peri-operative contamination of the surgical wound site.

Evaluation of the mandibular split patterns in sagittal split ramus osteotomy

PURPOSE

To evaluate the split patterns of the mandibular ramus in sagittal split ramus osteotomy (SSRO) using cone-beam computed tomography (CBCT) and examine the related anatomic features that may be associated with these split patterns.

PATIENTS AND METHODS

The authors designed and implemented a retrospective cohort study and enrolled a sample composed of consecutive patients with different maxillofacial deformities who underwent an SSRO from July 2011 through October 2012 at the Department of Orthognathic Surgery at the Tianjin Stomatological Hospital of Nankai University. The split patterns, which were selected at random at 1 side per patient, were evaluated by CBCT as the outcome variable 1 month after the operation. The predictor variable was composed of a set of heterogeneous anatomic variables that could be associated with the split patterns. Type I split was defined as a split at the lingual side near the mylohyoid sulcus. Type II split was defined as a split at the posterior border of the mandibular ramus. Appropriate bivariate and regression statistics were computed, and the level of statistical significance was set at a P value less than .05.

RESULTS

One hundred thirty patients with different maxillofacial deformities (62 male and 68 female; mean age, 23 yr) underwent an SSRO. Two types of split patterns of the mandibular ramus were observed in SSRO: a split at the lingual side near the mylohyoid sulcus, which occurred in 75.38% of patients, and split at the posterior border region of the mandibular ramus, which occurred in 24.62% of patients. No fracture lines were observed through the mandibular canal. The thickness of the lingual cortical bone between the mandibular canal and the posterior border of the ramus was significantly associated with the split patterns (P < .05). The thickness of the cortical bone in the posterior border of the ramus, the degree of the mandibular angle, and the shapes of the mandibular ramus in the axial plane also were found to influence these split patterns. There was no meaningful association between the split patterns and a patient's age and gender.

CONCLUSION

The split patterns of the mandibular ramus during SSRO were influenced by some anatomic features of the mandibular ramus. Therefore, examining the anatomy of the mandible with CBCT before surgery may play an important role in predicting the split patterns of the mandibular ramus during SSRO.

Low to high oblique ramus piezoosteotomy: a pilot study

Two major drawbacks of classical bilateral sagittal split osteotomy (BSSO) are occasional inferior alveolar nerve damage and bad splits. In order to avoid these two well-known disadvantages and benefit from ultrasonic bone cutting, a low-to-high oblique piezoosteotomy (LHO) was developed from Schlössmann's 1922 high oblique osteotomy, clinically evaluated with a standard and a novel osteosynthesis system. Eighty-five patients were retrospectively evaluated, 23 with an LHO osteotomy with standard osteosynthesis, 33 LHO with a dedicated plate osteosynthesis and compared to 29 patients with BSSO and standard osteosyntheses. The mean mandibular advancement in the LHO standard osteosynthesis/LHO dedicated plate osteosynthesis/BSSO collectives was 4.7 ± 2.5/7.8 ± 7.1/4.1 ± 2.8 mm, the mean one year relapse 2.6 ± 0.8 (p = 0.58)/1.4 ± 1.4 (p = 0.28)/2.1 ± 1.4 mm; the mean mandibular setback was 6.9 ± 3.6/7.7 ± 4.1/8.1 ± 4.9 mm and the one year relapse 2.9 ± 2.9 (p = 0.16)/1.4 ± 1.0 (p = 0.38)/1.5 ± 1.9 mm; clockwise rotation of the mandible was 5.2 ± 3.2/6.3 ± 5.1/10.2 ± 6.9°, the one year relapse 2.7 ± 1.2 (p = 0.18)/2.1 ± 1.7 (p = 0.09)/11.4 ± 9.3°; counterclockwise rotation averaged 6.4 ± 3.2/6.5 ± 7.9/6.5 ± 6.1° with a mean one year relapse of 3.3 ± 0.6 (p = 0.37)/3.7 ± 1.9 (p = 0.21)/4.5 ± 6.2°. LHO had 3%, BSSO 5% three months postoperative inferior alveolar nerve deficit (p = 0.17). The operation time was significantly shorter when LHO and dedicated plates were used compared to BSSO. Two broken conventional plates occurred in LHO, which stimulated the development of the dedicated plates used, one in BSSO; four bad splits in BSSO and two in LHO. Reosteosyntheses were performed using the newly developed dedicated "orthognathics" plate. LHO was successfully performed, easier and faster than BSSO. Gonial angle modifications were possible due to the oblique cut. Postoperative stability appears sufficient for moderate repositioning with a lower incidence of bad split and inferior alveolar nerve irritation, moreover blood loss was reduced. Since 2 standard miniplate fractures occurred in LHO, the "orthognathics" osteosynthesis was developed, applied and no further osteosynthesis fractures were seen.

Clinical and radiographic evaluation of a computer-generated guiding device in bilateral sagittal split osteotomies

The bilateral sagittal split osteotomy (BSSO) is one of the main orthognathic surgery procedures used for managing skeletal mandibular excess, deficiency or asymmetry. It is known to be a technique-sensitive procedure with high reported incidences of inferior alveolar nerve injury, bad splits and post-surgical relapse. With the increasing use of computer-assisted techniques in orthognathic surgery, the accurate transfer of the virtual plan to the operating room is currently a subject of research. This study evaluated the efficacy of computer-generated device at maintaining the planned condylar position and minimizing inferior alveolar nerve injury during BSSO. The device was used in 6 patients who required isolated mandibular surgery for correction of their skeletal deformities. Clinical evaluation showed good recovery of the maximal incisal opening and a reproducible occlusion in 5 of the 6 patients. Radiographic evaluation showed better control of the condyle position in both the vertical and anteroposterior directions than in the mediolateral direction. The degree of accuracy between the planned and achieved screw positions were judged as good to excellent in all cases. Within the limitations of this study and the small sample size, the proposed device design allowed for good transfer of the virtual surgical plan to the operating room.

[High oblique sagittal split osteotomy]

INTRODUCTION

Bilateral sagittal split osteotomy has become the standard mandibular surgery for the treatment of dental and facial deformities, even for small ones. The morbidity must be as low as possible.

TECHNICAL NOTE

We describe a technique with reduced split surfaces, with an oblique bone section rather than a split. The bone is cut complete, on the posterior edge of the ramus, following an oblique line from above the lingula downward and laterally towards the supra-angular region.

DISCUSSION

This section preserves the inferior alveolar nerve. It greatly decreases the risk of neurological sequels. Most mandibular movements are possible except for important advancement and elongation of the ramus.

Prevalence and treatment of dentofacial deformities on a multiethnic population: a retrospective study

INTRODUCTION

The purpose of the present study was to retrospectively analyze patients with dentofacial deformities attending a reference center in a Brazilian educational institution who sought orthosurgical treatment.

MATERIAL AND METHODS

The medical records of 251 patients who sought treatment from 2003 to 2011 at Piracicaba Dental School, State University of Campinas (Unicamp) were analyzed. The exclusion criteria were as follows: patients presenting syndromes and labiopalatal clefts; in addition, incomplete records were excluded from the study.

RESULTS

The prevalence of dentofacial deformities was greater in women (60.93 %), as well as leukoderma patients (69.22 %). The main motivation for treatment was functional (52 %), followed by esthetics (27 %). As for skeletal pattern, class III was the most incident (55 %), followed by class II (29.5 %) and class I (15.5 %). Regarding the type of deformity, class I patients had predominantly maxillary atresia (53 %). In the case of class II patients, the main deformity was anteroposterior mandibular deficiency (89 %), and in class III, anteroposterior maxillary deficiency (51 %).

DISCUSSION

The results of the present study suggest that the profile of patients bearing dentofacial deformities in this population is composed of mostly young women motivated by functional issues, and class III skeletal deformity is the most common.

Morphologic features of the mandibular ramus associated with increased surgical time and blood loss in sagittal split-ramus osteotomy

PURPOSE

To determine whether specific morphologic features of the mandibular ramus can predict increased surgical time and blood loss in sagittal split-ramus osteotomy (SSRO).

MATERIALS AND METHODS

The clinical and morphologic features of the mandibular ramus, obtained from computed tomographic images (n=50), were analyzed to predict the surgical time, the time required for ablation of the medial mandibular ramus, and the time required for sectioning of the mandible in performing a modified Obwegeser SSRO.

RESULTS

Significant factors associated with surgical time were an anterior border of the ramus at least 10.5 mm wide, a maximal length of the thickened ramus of at least 8.5 mm, and a distance from the mandibular incisor to the posterior border of the mandible of at least 97.5 mm. There were significant differences in blood loss between the 2 axial aspects of the medial ramus.

CONCLUSIONS

The greater protrusion of the medial oblique ridge, thickened ramus, and longer distance from the mandibular incisors to the posterior border of the mandible may increase the surgical time and blood loss in patients undergoing classic SSRO. When planning or performing an SSRO, the morphologic features obtained from computed tomographic images may help surgeons gain a better understanding of the potential difficulties when the surgical site involves the medial aspect of the ascending ramus of the mandible.

Ultrasonic orthognathic surgery: enhancements to established osteotomies

The use of a novel ultrasonic osteotome enabled the authors to modify well-established orthognathic osteotomies to more favourably address the anatomy. For this purpose, they utilized a powerful ultrasonic device with tissue-selective cutting characteristics that was originally developed for spinal osteotomies and nerve decompression (BoneScalpel™ by Misonix Inc., Farmingdale, NY, USA). Its straight ultrasonic blade was adapted for dual action, and a soft protective element was added. The product modifications and the related changes regarding maxillary and mandibular osteotomies are explained in detail. A series of 83 patients underwent orthognathic surgery with the BoneScalpel ultrasonic osteotome. All osteotomies within this study group were performed purely ultrasonically and without the auxiliary use of reciprocating saws or rotary burrs. The complications, alveolar nerve impairment and bad splits were assessed. To assess the quality of the lingual osteotomies and pterygomaxillary separation, three-dimensional scanning was performed on 30 patients. In conclusion, the BoneScalpel™ ultrasonic osteotome enabled improved control over orthognathic osteotomies and resulted in significant reductions in the occurrence of nerve impairment and bad splits.

Impact of the mandibular divergence on the position of the inferior alveolar nerve and mylohyoid nerve: a computed tomography study and its relevance to bilateral sagittal split osteotomy

PURPOSE

Bilateral sagittal split osteotomy (BSSO) is the most common procedure used to treat mandibular deformities. BSSO procedures include the Epker technique and the Dal Pont technique which are the most frequently used. Because of the intramandibular pathway of the inferior alveolar nerve (IAN), neurosensory disturbance of the lower lip and chin is the most common complication of BSSO. This study performed quantitative measurements from computed tomographic (CT) data obtained on dry human mandibles. The main aim of the study was to evaluate if mandibular divergence can predict the position of the IAN and the mylohyoid nerve (MHN) to prevent nerve injury.

METHODS

After CT and 3D reconstruction of 65 dry mandibles, 30 measurements were made on 3 planes for each hemi-mandible. This allowed analysis of the IAN and MHN pathways. Three groups of hemi-mandibles were created depending on their divergence, and a statistical analysis was performed.

RESULTS

Eight out of the 30 measurements showed a significant difference among the 3 groups. There was no significant difference for the remaining 22 measurements.

CONCLUSIONS

The IAN seems to have a more superior position in the groups of mandibular hypo- and hyper-divergence. Orthognathic surgeons should use a more superficial retromolar bone incision in these cases. Finally, the Epker technique would be safer for preserving the MHN in normo- and hypo-divergent patients.

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.

Management of chronic facial pain

Pain persisting for at least 6 months is defined as chronic. Chronic facial pain conditions often take on lives of their own deleteriously changing the lives of the sufferer. Although much is known about facial pain, it is clear that those physicians who treat these conditions should continue elucidating the mechanisms and defining successful treatment strategies for these life-changing conditions. This article will review many of the classic causes of chronic facial pain due to the trigeminal nerve and its branches that are amenable to surgical therapies. Testing of facial sensibility is described and its utility introduced. We will also introduce some of the current hypotheses of atypical facial pain and headaches secondary to chronic nerve compressions and will suggest possible treatment strategies.

Short-term periodontal and microbiological changes following orthognathic surgery

OBJECTIVE

Aim of the present study was to evaluate the influence of orthognathic surgery on the development of periodontal and microbiological changes.

MATERIALS AND METHODS

Fifteen consecutively treated patients with a mean age of 24.9±7.7 years receiving orthognathic surgery were included in the present study. Plaque index (PI) and concentrations of 11 periodonto-pathogenic bacteria were recorded one day prior to surgery (t(0)) and one week (t(1)) and six weeks (t(2)) post-surgery. In addition, a complete periodontal examination including pocket probing depth (PPD), gingival recession (GR), clinical attachment level (CAL), bleeding on probing (BOP) and width of keratinized gingiva (WKG) was conducted at t(0) and t(2). For statistical analysis, general linear model and paired t-test were applied.

RESULTS

A significant increase of PI (t(0)-t(1), p=0.037) was followed by a significant decrease (t(1)-t(2), p=0.017). Apart from Eikenella corrodens (p=0.036), no significant microbiological changes were recorded. PPD significantly increased on oral sites (p=0.045) and GR especially on buccal sites (p=0.001). In the incision area the development of GR was significantly higher on the test (buccal) than on the control sites (oral). Both gingival biotypes were affected by GR.

CONCLUSIONS

Orthognathic surgery causes statistically significant changes of periodontal parameters, but these changes do not necessarily impair the aesthetic appearance of the gingival margin.

Osteomyelitis after bilateral sagittal split osteotomy: case report and a review of the management

OBJECTIVES

The purpose of this paper is to report a case of osteomyelitis following a bilateral sagittal split osteotomy in a patient who underwent 2-jaw surgery. A review of the management of osteomyelitis is included, with a discussion of implications for the reconstruction of the mandible after treatment for osteomyelitis.

STUDY DESIGN

A case of a rapidly progressing osteomyelitis is presented with a detailed review of the management of osteomyelitis, using this case to illustrate key points of management.

RESULTS

In a very short period of time the patient lost a significant portion of the left side of her mandible. The actual management that she underwent, as well as some of the controversies that are present with the treatment of osteomyelitis, is discussed.

CONCLUSION

Although osteomyelitis of the mandible usually is seen after odontogenic infections and trauma, it can occur in patients undergoing elective osteotomies. When recognized, it should be aggressively treated.

Mandibular stability after SSRO with or without postoperative maxillo-mandibular fixation for Class III malocclusion

OBJECTIVE

The objective of this study was to assess the usefulness of maxillo-mandibular fixation (MMF) from a viewpoint of skeletal and occlusal stability and to investigate the complications after surgery with and without MMF.

MATERIALS AND METHODS

Twenty-seven patients who underwent surgical correction of class III malocclusion were analyzed. The surgical procedure in all cases consisted of a bilateral sagittal splitting ramus osteotomy (SSRO). The segments were then fixed rigidly with titanium screws. A postoperative MMF was performed in 13 patients within 1 day of the SSRO. The MMF lasted for 1 week. The other 14 patients were free to move their jaw on the day of the surgery and received occlusal guidance with elastics starting from the third postoperative day. Cephalograms were taken preoperatively, at 1 day postoperatively and at 1, 3, 6, 12, and 24 months after surgery. Skeletal and occlusal stabilities along with postoperative complications were then assessed.

RESULTS

Discomfort of the pharynx and postoperative pain was more severe in the MMF group. Even without MMF, occlusion was guided to the ideal position by an average of 5.3 days after surgery. Occlusal and skeletal stability was satisfactory in both groups, and there was no correlation between the surgical results and postoperative MMF.

CONCLUSION

MMF may not be necessary after a rigid fixation SSRO, considering the risks of airway problems.

Piezoosteotomy in orthognathic surgery versus conventional saw and chisel osteotomy

INTRODUCTION

Piezoosteotomy was assessed as alternative osteotomy method in orthognathic surgery regarding handling, time requirement, nerve and vessel impairment.

MATERIALS AND METHODS

In this comparative clinical experience, 90 patient's orthognathic surgery procedures were performed in typical distribution prospectively by piezoosteotomy: 34 (38%) monosegment, 47 (52%) segmented LeFortI osteotomies, 94 (52%) sagittal split osteotomies, 11 (12%) symphyseal, and 4 (2%) mandibular body osteotomies. As controls served 90 retrospective patients with conventional saw and chisel osteotomy: 58 (64%) monosegment, 27 (30%) segmented LeFortI osteotomies, 130 (72%) sagittal split, and 4 (4%) symphyseal osteotomies.

RESULTS AND DISCUSSION

Piezoosteotomies were individually designed to interdigitate the jaw segments after repositioning. The pterygomaxillary suture weakened angulated tools; auxiliary chisels were required in 100% of cases for the nasal septum and lateral nasal walls, in 33% for pterygoid processes. The dorsal maxilla as the pterygoid process were easily reduced; 15% mandibular osteotomies required sawing, while the lingual dorsal osteotomy was performed by manual feedback due to limited visibility. Bloodloss decreased from average 537 +/- 208 ml vs. 772 +/- 338 ml (p = 0.0001). Operation time remained unchanged: 223 +/- 70 min vs. 238 +/- 60 min (p = 0.2) for a conventional bimaxillary procedure. Clinical courses and reossification were unobtrusive. Alveolar inferior nerve sensitivity was retained in 98% of the piezoosteotomy collective versus 84% of controls (p = 0.0001) at 3 months postoperative testing.

CONCLUSION

Piezoelectric osteotomy did not prolong the operation and reduced blood loss as alveolar nerve impairment. A few patients required additional sawing or chisel. Piezoelectric screw insertion as complex osteotomies may be initiated to simplify the procedure and increase segment interdigitation after repositioning as to minimize the osteofixation time and dimensions.