Mandibular Orthognathic Surgery Research Articles

English

Introduction The aim of the present study was to highlight the incidence and patients’ subjective perception of neurosensory disturbance and the degree of satisfaction after bilateral sagittal split osteotomies, at least 3 years after surgery. Materials and Methods The sample population consisted of all 52 consecutively operated subjects who had undergone bilateral sagittal split osteotomies between the years 2003 and 2008 at the Department of Maxillofacial Surgery at Orebro University Hospital. Patients were contacted by a letter and asked to complete a questionnaire about perceived sensory changes after the operation and their satisfaction with the result of the operation. Discussion The lack of standard methods for evaluating neurosensory disturbance is evident. Thus, the evaluation methods in the literature vary from strictly subjective to strictly objective. However, the most important factor, from the patient’s point of view, must be the patient’s own perception of the nerve impairment, not what the objective results indicate. Conclusion Half of the operated subjects had longlasting neurosensory disturbance. However, the majority of the patients (89%) were satisfied with the result of the operation despite sensory disturbances of some degree. It appears that neurosensory disturbance is not the main determining factor of patient satisfaction and seems outbalanced by preoperative information and results of function and aesthetics. Introduction The bilateral sagittal split osteotomy (BSSO), described as early as in 19571, is the most frequently used procedure to correct mandibular skeletal discrepancies by lengthening or shortening the mandible. Neurosensory disturbances (NSDs) of the lower lip and chin following this procedure are commonly due to lesions of the inferior alveolar nerve and its terminal branch, the mental nerve. This can be caused by surgical oedema, stretching, pressure, the split itself and the possible compression of the nerve during fixation2,3. The symptoms of a nerve lesion are usually varying degrees of numbness of the lower lip and chin4. Although the nerve impairment is of purely sensory nature, and consequently no motor deficit occurs, the problem concerns the patient, as anyone who has had an inferior alveolar nerve block for dental anaesthesia can well understand. This sensory deficit is not only an unpleasant sensation, but may also affect the patient’s ability to talk and masticate efficiently without traumatising the involved area2. There are many published studies of NSD in patients undergoing orthognathic surgery, but there are few studies evaluating the patients’ own perception, which could differ from the surgeon’s judgement, and often is underestimated by clinicians when compared to the patients’ subjective symptoms5,6. Most studies on the outcome of sensory function after BSSO have used the final follow-up for evaluation (2–2.5 years)3. The aim of the present study was to descriptively highlight the incidence and patients’ subjective perception of sensory impairment in the lower lip and chin and the degree of satisfaction after mandibular orthognathic surgery with BSSO at least 3 years after surgery. Materials and Methods The study protocol was approved by the Regional Ethical Review Board in Uppsala, Sweden, which follows the guidelines of the Declaration of Helsinki. All the patients (n = 52; 23 men and 29 women) who had an up-to-date address and had undergone BSSO, between the years 2003 and 2008, at the Department for Maxillofacial Surgery at Orebro University Hospital, Orebro, were contacted by a letter and were asked to participate in this study. The records of these patients were reviewed at the Department of Orthodontics in Orebro County. Subjects with craniofacial syndromes, facial trauma, pre-existing NSD and out-of-date home addresses were not considered eligible for the study. Seven subjects fulfilled the exclusion criteria. The youngest patient in this study was 21 years old. The observation period between the years 2003 and 2008 indicates a follow-up from 3 up to 8 years post-operation in this study. The operation technique used for BSSO at the Department for Maxillofacial Surgery was standardised, * Corresponding author Email: farhan.bazargani@orebroll.se 1 Public Dental Clinic, Folktandvarden Drottninggatan, Helsingborg, Sweden 2 Postgraduate Dental Education Center, Orebro, Sweden 3 Department of Social Dentistry, Faculty of Odontology, Malmo University, Malmo, Sweden 4 Department of Orthodontics, Postgraduate Dental Education Center, P.O. Box 1126, SE-701 11, Orebro, Sweden

Class III malocclusion with severe anteroposterior discrepancy

This study aims at reporting the clinical case of a patient with Class III skeletal malocclusion with severe maxillary deficiency, producing a reduced midface associated with severe mandibular prognathism. The pre-surgical orthodontic preparation was composed mainly by dentoalveolar expansion and repositioning of the incisors in the lower arch. Then, a combined maxillary and mandibular orthognathic surgery was performed. The treatment objectives were achieved, with significant improvement in facial esthetics and occlusion, followed by post-treatment stability. This case was presented to the Brazilian Board of Orthodontics and Facial Orthopedics (BBO), as part of the requirements for obtaining the title of Diplomate by BBO.

Monitoring dental pulp sensibility and blood flow in patients receiving mandibular orthognathic surgery

To investigate the effect of orthognathic surgery, in particular genioplasty, on pulp sensibility and pulp blood flow (PBF). Pulp blood flow monitoring and CO(2) pulp sensibility testing were performed on 101 mandibular anterior teeth from 17 subjects who received mandibular bilateral sagittal split osteotomy (BSSO) with or without genioplasty and other maxillary surgical procedures combined with orthodontic treatment. A laser Doppler flowmeter was used to monitor PBF using customized acrylic splints for each subject. Preoperative baseline scores were recorded from up to 1 week preoperatively, and subsequently monitored for up to 18-28 weeks postoperatively. The data were analysed by RMANOVA and pairwise comparisons. Statistical significance was defined as P < 0.05. The average PBF in subjects who received genioplasty was not significantly different to those who received no genioplasty (F = 0.076, P = 0.784). In both groups, PBF decreased significantly postoperatively (F = 23.323, P = 0.000) and remained significantly lower (P = 0.000) than preoperative values at all times. PBF decreased markedly for 1-2 weeks postoperatively in patients who received genioplasty. However, there were no statistical differences between the PBF values at any time postoperatively for either group (P > 0.05). All teeth in both groups responded to CO(2) preoperatively. The average number of teeth that responded to CO(2) postoperatively in the genioplasty group was lower without significant difference when compared to the group without genioplasty (binomial distribution F = 2.63, P = 0.1256, normal distribution F = 2.98, P = 0.1048). At each progressive period after 1-2 weeks following surgery, the number of teeth responding to CO(2) increased significantly (P < 0.001) in both groups. At the end of the study, in the genioplasty group 81.1% of teeth responded to CO(2) compared to all teeth in the group without genioplasty. Pulp blood flow decreased and remained significantly lower than preoperative values in mandibular anterior teeth postoperatively with or without genioplasty. At no time was the absence of PBF recorded. The number of teeth that responded to CO(2) decreased markedly postoperatively but recovered significantly over time. All teeth regained sensibility in the group without genioplasty at the end of the study. There were neither common trends nor coincidence in the recovery of PBF and pulp sensibility.

The spatial location of the mandibular canal in Chinese: a CT study

The inferior alveolar nerve (IAN) is vulnerable to injury from mandible fractures and surgical procedures so anatomical variations of IAN are important. Postoperative sensory alteration of the lip and chin region is high after mandibular orthognathic surgery. The incidence of IAN paresthesia following sagittal split ramus osteotomy (SSRO) ranges from 54% to 86% at 4–8 days, 41 to 75% at 1 month, 33 to 66% at 3 months, 17 to 58% at 6 months and 15 to 33% at 1 year postoperatively. This study determined the anatomical position of the mandibular canal in relation to cortical bone and molar teeth in Chinese using archived CT records. The mandibular canal was the farthest from the buccal cortex at the second molar region (mean 6.79 mm; minimum distance 4.80 mm). The anatomical location of the mandibular canal in local Chinese compares with studies on Asian cadavers. The mandible body was thickest in the region of the second molar (11.9 mm). The vertical buccal cut for SSRO should be in the region of the mandibular second molar where the bone is thickest and the mandibular canal is furthest from the buccal cortex. The safe depth for the vertical buccal cut is 4.8 mm (minimum horizontal distance).

Development of a simulation system in mandibular orthognathic surgery based on integrated three-dimensional data

PurposeSurgical simulation should reflect the 3D movement of dentition and the resultant movement of the osteotomized segments, which can influence surgical outcome. The present study was aimed at developing a new simulation system that enables virtual osteotomy of a given surgical situation and evaluation of the bony interference between the osteotomized segments of the mandible.Subjects and methodsThe data of 3D computer tomography (CT) for maxillomandibular dental casts were integrated into the standard coordinates of a 3D cephalogram. To evaluate the accuracy of the system, measurement errors of the 3D CT virtual model from a dry skull were compared with the computer simulation system and a contact-type 3D digitizer. To examine the clinical accessibility, 15 mandibular prognathism patients with mild to severe asymmetry were evaluated with the simulation program.ResultsThe average error of measurement in all directions was 1.31 mm. It was possible to simulate various osteotomy procedures by conversion of the 3D coordinates of the dental cast and CT data into the standard coordinate system of a 3D cephalogram. Using this simulation system, it was possible to prevent condylar torque or segment malpositioning by removing the bony interference visualized by a 3D virtual model.ConclusionA new system, which enables the precise visualization of osteotomized segments and calculation of bony interference, was proposed in the present study. This new system provides an acceptable precision of treatment planning of orthognathic surgery, especially for facial asymmetry.

Análise da fidelidade do traçado predictivo em pacientes submetidos à cirurgia ortognática em mandíbula

OBJETIVO: a proposta desse trabalho foi analisar a fidelidade dos traçados predictivos realizados para cirurgias ortognáticas, por meio de análise cefalométrica do pré e pós-operatório de sete dias, em pacientes submetidos à correção de deformidade mandibular. MÉTODOS: foram utilizadas telerradiografias cefalométricas de perfil de 17 pacientes submetidos à cirurgia ortognática de mandíbula. Foram realizados traçados cefalométricos do pré e do pós-operatório de 7 dias com marcação dos pontos côndilo (Co), pogônio (Pog), goníaco (Go), mento (Me), ponto B (B) e incisivo (I). A análise foi baseada na diferença obtida pela sobreposição dos traçados pré-operatório, predictivo e pós-operatório. Os pontos foram projetados em um plano cartesiano para medição das suas distâncias em milímetros. Os dados obtidos foram submetidos à análise estatística por meio do teste t de Student pareado (± = 0,05). RESULTADOS: no eixo horizontal, foi observada diferença média, entre a mudança planejada e a obtida nos traçados cefalométricos pós-operatórios, estatisticamente significativa nos pontos Pog (p = 0,014) e I (p = 0,008). No eixo vertical, não verificou-se diferença estatística significativa para os pontos cefalométricos marcados (p &gt; 0,05). CONCLUSÕES: o traçado predictivo contribuiu para a avaliação pré-operatória do paciente e, consequentemente, para a otimização do tratamento. Entretanto, ele não se mostrou totalmente fiel nos casos analisados, com leve subestimação das alterações esqueléticas horizontais. Essas alterações devem ser consideradas no planejamento e acompanhamento pós-operatório dos pacientes submetidos à cirurgia ortognática em mandíbula.

Biomechanical evaluation of a T-shaped miniplate fixation of a modified sagittal split ramus osteotomy with buccal step, a new technique for mandibular orthognathic surgery

The purpose of this study was to biomechanically evaluate the stability of a T-shaped miniplate fixation of a modified sagittal split ramus osteotomy (MSSRO) with buccal step and to compare it with single or double-parallel straight miniplates fixing a standard sagittal split ramus osteotomy (SSRO). Eighteen Synbone mandibular replicas were used in the study and divided into 3 groups. Standard SSRO was applied in the first and second groups, and the third group was cut for MSSRO with buccal step. After 7 mm of advancement, fixation modalities for the 3 groups included a single straight miniplate, double-parallel straight miniplates, and a T-shape miniplate, respectively. Each model was secured in a jig and subjected to vertical load on the anterior teeth. The T miniplate group showed a significantly higher value for stability than the group with a single straight miniplate. There was no significant difference in stability between the T miniplate and the double-parallel straight miniplate groups. For mandibular advancement surgery of 7 mm in a laboratory environment, a T-shaped miniplate used with MSSRO and buccal step as a combination significantly optimize the resistance and stability of the fixation compared with a standard SSRO fixed with a single straight miniplate.

A biomechanical evaluation of sagittal split ramus osteotomy with modified step secured by T-shape miniplate—a new plating technique for mandibular orthognathic surgery

A biomechanical evaluation of sagittal split ramus osteotomy with modified step secured by T-shape miniplate—a new plating technique for mandibular orthognathic surgery

A national review of mandibular orthognathic surgery activity in the National Health Service in England over a nine year period: Part 2 - patient factors

We aimed to investigate patients who had mandibular orthognathic surgery in England for the period 1 April 1997–30 March 2006. Data on hospital inpatient activity were extracted from the NHS Hospital Episode Statistics (HES) database for all mandibular orthognathic surgical procedures between these dates. Details of patients were investigated in relation to clinical details, socioeconomic status, other diagnoses, and clinical outcomes. Mandibular orthognathic operations were done for 8941 patients in England over the 9-year period, and the ratio of women: men was 1.7:1. The mean (SD) age at operation was 24 (9) years with no difference between sexes. There was a socioeconomic gradient in patients requesting treatment, most of whom lived in relatively affluent areas. The most common other diagnosis was “additional dentofacial anomalies” (8% of episodes). Mental or behavioural diagnoses were recorded in 41 patients (<1%). One patient died in hospital. Our results confirmed the differences in sex in patients receiving orthognathic care and highlighted socioeconomic inequalities in the treated patients. A number of coexisting diagnoses were also identified.

A national review of mandibular orthognathic surgery activity in the National Health Service in England over a nine year period: Part 1 - Service factors

We aimed to investigate the changing provision of mandibular orthognathic surgery in England for the period 1 April 1997–30 March 2006. Data on hospital inpatient activity were extracted from the NHS Hospital Episode Statistics (HES) database for all mandibular orthognathic surgical procedures between these dates. We investigated provider factors (in which units providing services were classified as undertaking either high or low volumes of activity) and temporal changes. There was a steady increase in the number of procedures over time, and a decrease in the mean time spent in hospital ( p < 0.001). Provider units with high volumes of activity had shorter inpatient stays than those that provided low volume ( p < 0.001) and exhibited a greater reduction in the duration of inpatient stays ( p = 0.02). Patterns of care are changing, and increasing numbers of treatments are being done as day-cases ( p < 0.001). Units with high volumes seem to be more efficient in terms of duration of hospital stay than low volume units. However, our data do not allow an insight into the quality of care provided, and further research is needed to address this issue.

Closure of anterior open bites with mandibular orthognathic surgery only

Closure of anterior open bites with mandibular orthognathic surgery only

Systemic Inflammatory Response Syndrome and Postoperative Complications after Orthognathic Surgery

Symptoms of Systemic Inflammatory Response Syndrome (SIRS) presenting immediately after surgery have lately been regarded as potential warnings of impending postoperative complications and multiple organ failure. Reports discussing the relationship between operative stress and SIRS are found in the field of digestive surgery, but not in that of oral surgery. Sixty-five patients with jaw deformity who had undergone maxillary and mandibular orthognathic surgery (Le Fort I osteotomy and sagittal splitting ramus osteotomy) between September 2003 and October 2006 were involved in this study. A search based on the SIRS diagnostic criteria resulted in assignment of 33 cases to the SIRS group and 32 cases to the non-SIRS group. Postoperative complications occurred in 27.3% of the SIRS group and 0.0% of the non-SIRS group (p<0.01). In four cases, a postoperative fluctuation in IL-6 level evaluated. These results suggest the importance of careful management of postoperative SIRS patients in preventing complications.

Three-dimensional soft tissue changes associated with mandibular orthognathic surgery

Three-dimensional soft tissue changes associated with mandibular orthognathic surgery

Endoscopic vertical ramus osteotomy: early clinical results.

The benefits of minimally invasive surgery have been well documented. The purpose of this report was to present early results in a series of patients who had endoscopic mandibular orthognathic surgery. Patients and methods This is a retrospective evaluation of 14 patients who underwent endoscopic vertical ramus osteotomy and rigid fixation for the treatment of mandibular prognathism (n = 9), malocclusion secondary to trauma (n = 3), or other pathology (n = 2). A 1.5-cm incision was made directly below the mandibular angle. The dissection was continued bluntly to the masseter muscle, which was incised using a needlepoint electrocautery. Then, with endoscopic elevators, an optical cavity was created for insertion of a Hopkins endoscope and visualization of the ramus/condyle unit. Anatomic landmarks were identified and the operation carried out with specially designed endoscopic equipment. Preoperative (T0), postoperative (T1), and follow-up (T2) clinical examinations; lateral cephalograms; and panoramic radiographs were used to evaluate the outcomes. The procedures performed included: vertical ramus osteotomy (n = 13 patients, 23 sides) and condylectomy plus vertical ramus osteotomy (n = 1 patient, 1 side). Mean operating time was 37 minutes per side. One patient had temporary marginal mandibular nerve weakness. The occlusal result was as planned in all cases. Panoramic radiographs documented postoperative ramus/condyle unit position and lateral cephalograms documented mandibular position. The results of this case series indicate that endoscopic vertical ramus osteotomy with rigid fixation is feasible for correction of a variety of mandibular deformities.

Dysfonctionnement des muscles labio-mentonniers et indications de la chirurgie d'affaiblissement

Hyperactivity of the muscles controlling the lower lip and chin (muscles of the chin, buccinator, orbicularis, etc.) can be demonstrated at different levels of the muscular complex and may act as an elastic force against the mandibular alveolar process. Dysfunction in this region may lead to reduction of the alveolar bone quantity, reducing the tooth-bone equilibrium. If this balance is disturbed, periodontal lesions, a lower incisal crowding and a retrognathic mandibular process may result. Surgery to correct overactivity of the chin muscles is described here step by step. Resection of the muscles may be undertaken on a greater or lesser scale and striation of the muscle may also allow reduction of muscular strength. Reducing the muscular activity creates a better environment for the development of the mandible and its alveolar process. Depending on the clinical situation, these techniques can be associated with genioplasty, bone graft and/or mandibular orthognathic surgery.

Evaluation of video imaging prediction in combined maxillary and mandibular orthognathic surgery

The purpose of this study was to evaluate the accuracy of the soft tissue profile “line drawings” predicted by Quick Ceph Image in combined maxillary and mandibular orthognathic surgical procedures. Preoperative (mean = 27.7 days presurgical) and posttreatment (mean = 11.5 months postsurgical) lateral cephalograms of 40 white patients (10 males and 30 females) who had completed treatment that involved orthodontics, one-piece LeFort I osteotomy, and mandibular advancement by bilateral sagittal split osteotomy with or without genioplasty were used in the study. Forty-five lateral hard and soft tissue landmarks were digitized, using the “on-screen” digitizing option, for each cephalogram and for each computer predicted posttreatment tracing. A customized analysis consisting of 24 linear and 4 angular measurements was used to analyze the differences between the actual posttreatment cephalometric landmark measurements and computer predicted landmark measurements. Statistically significant differences between the posttreatment cephalometric soft tissue profiles and the computer predicted soft tissue profiles were analyzed for the total sample, patients grouped according to: magnitude and direction of maxillary movements, adjunctive genioplasty procedure, V-Y closure of the LeFort I incision, and gender and age differences. The results indicated that for some of the soft tissue landmarks, differences were found between the posttreatment and the computer predicted profiles. Differences between the predicted and actual posttreatment soft tissue profiles may be attributed to the inaccuracy of Quick Ceph Image's default soft to hard tissue ratios when predicting the soft tissue response to combined maxillary and mandibular orthognathic surgical procedures. (Am J Orthod Dentofac Orthop 1997;112:656-65.)

The Re-establishment of Molar Occlusion following Orthognathic Surgery

The effect on distal molar occlusion following mandibular orthognathic surgery is highlighted. Two cases are presented in which at the completion of orthodontic/surgical treatment a stable molar occlusion was re-established by adjunctive restorative treatment. The clinical problem highlighted, illustrates the importance of restorative support for patients with residual post-orthodontic and post-surgical occlusal problems.

Evaluation of video imaging prediction in combined maxillary and mandibular orthognathic surgery: P. Mike Upton. Birmingham, Alabama: Department of Orthodontics, School of Dentistry, University of Alabama-Birmingham, 1994.

Evaluation of video imaging prediction in combined maxillary and mandibular orthognathic surgery: P. Mike Upton. Birmingham, Alabama: Department of Orthodontics, School of Dentistry, University of Alabama-Birmingham, 1994.

The use of ultrasound to determine the position of the mandibular condyle

A randomized, single blind study of 20 patients examined the accuracy of ultrasound in establishing the position of the mandibular condyle in relation to the glenoid fossa. The sonographic technique is described. The temporomandibular joint was imaged sonographically with the patients in an open- and a closed-mouth position as a model for condylar sag and proper condylar seating, respectively, during mandibular ramus osteotomy procedures. One radiologist identified condylar position correctly in 38 of 40 still ultrasound images, with a sensitivity and a specificity of 95%. During real time ultrasound examination, it is possible to visualize varying degrees of condylar movement in relation to the glenoid fossa. The results of this study support the potential use of ultrasound as an adjunct to mandibular orthognathic surgery.

Simultaneous maxillary and mandibular orthognathic surgery stabilized by rigid internal fixation

Rigid internal fixation was used successfully in 111 consecutive cases in which both the maxilla and the mandible were mobilized simultaneously. The use of rigid fixation allowed for early mobilization of the mandible, which facilitated resumption of orthodontic therapy after surgery. The favorable short-term results achieved indicate the need to study the long-term stability of the technique.