The Comprehensive AOCMF Classification System: Mandible Fractures-Level 3 Tutorial

Two versus three magnesium screws for osteosynthesis of mandibular condylar head fractures: a finite element analysis

OBJECTIVES

Previous finite element analyses (FEA) have shown promising results for using two titanium screws in treating mandibular condylar head fractures but limited mechanical stability of a two-screw osteosynthesis with magnesium screws. Given the potential benefits of magnesium screws in terms of biocompatibility and resorption, this study aimed to compare two- and three-screw osteosynthesis solutions for a right condylar head fracture (AO CMF type p) with magnesium screws with a FEA.

MATERIALS AND METHODS

A previously validated finite element model simulating a 350 N bite on the contralateral molars was used to analyze von Mises stress within the screws, fragment deformation, and fracture displacement. All screws were modeled with uniform geometric specifications mirroring the design of Medartis MODUS® Mandible Hexadrive cortical screws.

RESULTS

The three-screw configuration demonstrated lower values for all three parameters compared to the two-screw scenario. There was a 30% reduction in maximum von Mises stress for the top screw and a 46% reduction for the bottom screw.

CONCLUSIONS

Fracture treatment with three magnesium screws could be a valuable and sufficiently stable alternative to the established treatment with titanium screws. Further studies on screw geometry could help improve material stability under mechanical loading, enhancing the performance of magnesium screws in clinical applications.

CLINICAL RELEVANCE

The use of magnesium screws for osteosynthesis of mandibular condylar head fractures offers the benefit of reducing the need for second surgery for hardware removal. Clinical data is needed to determine whether the advantages of resorbable screw materials outweigh potential drawbacks in condylar head fracture treatment.

A finite element analysis on the indication for extracting partially impacted mandibular third molars considering mandibular trauma

BACKGROUND

Patients presenting with partially impacted lower third molars (M3) have a higher likelihood of experiencing angle fractures while simultaneously decreasing the risk of condylar fractures. However, the specific biomechanical mechanism responsible for this occurrence remains unclear. Moreover, there is an ongoing debate regarding whether the removal of M3s might actually increase the risk of condylar fractures. This study aimed to evaluate how the presence of M3s influences mandibular fractures resulting from blows to the symphysis and lateral mandibular body, and to determine the indication for extracting M3s in such cases.

METHODS

Models of the mandible with a partially M3-impacted model (M3I), M3-extracted model (M3E), and M3-absent model (M3A) were generated using a computer. A traumatic blown force of 2000 N was applied to the symphysis and the right body of the mandible. Von Mises and principal stresses were analyzed, and failure indexes were determined. Two cases of mandibular linear fractures were chosen for model verification and interpretation.

RESULTS

When force was applied to the symphysis, the condylar region exhibited the highest stress levels, while stress in the mandibular angle region was much less regardless of the M3 state. On applying the force to the right mandibular body, stress in the condylar region decreased while stress in the mandibular body increased, especially in the blown regions. Impacted tooth or cavity formation post-M3 extraction led to uneven stress distribution on the blown side of the mandible, increasing the risk of mandibular angle fractures. In cases where M3 was absent or the extraction socket had healed, stress from lateral traumatic blown force was evenly distributed along both the inner and outer oblique lines of the mandible, thereby reducing the risk of mandibular fractures.

CONCLUSIONS

The reduced risk of condylar fractures in patients with partially impacted lower M3s and mandibular angle fractures is mainly due to lateral blows on the mandible, which generate less stress in the condylar region than blows on the mandibular symphysis, rather than being caused by the M3 itself. Extraction of the lower M3 can decrease the risk of mandibular fractures, with a minor influence on condylar fractures.

Surgical treatment of clinically infected mandibular fractures

PURPOSE

To clarify reasons for infections, surgical techniques, and occurrence of postoperative surgical site complications in infected mandibular fractures.

METHODS

Patients with clinically infected mandibular fracture of the dentate part without preceding surgery were studied retrospectively. Clinical infection was defined to occur if pus, abscess, or a fistula in the fracture area was present. Patient-, fracture-, and surgery-related variables were evaluated, and predictors for postoperative complications were analysed.

RESULTS

Of 908 patients with surgically treated fracture in the dentate part of the mandible, 41 had infected fracture at the time of surgery (4.5%). Of these patients, 46.3% were alcohol or drug abusers. Median delay from injury to surgery was 9 days. Patient-related factors were the most common cause for delayed surgery (n = 30, 73.2%), followed by missed diagnosis by a health care professional (n = 8, 19.5%). Twenty-two fractures were treated via extraoral approach (53.7%) and the remaining 19 intraorally (46.3%). Postoperative surgical site complications were found in 13 patients (31.7%), with recurrent surgical site infections predominating. Notable differences between total complication rates between intraoral and extraoral approaches were not detected. Secondary osteosynthesis for non-union was conducted for one patient treated intraorally.

CONCLUSIONS

Postoperative surgical site complications are common after treatment of infected mandibular fractures, and these occur despite the chosen surgical approach. Infected mandibular fractures heal mainly without bone grafting, and non-union is a rare complication. Due to the high complication rate, careful perioperative and postoperative care is required for these patients.

In-silico study of type 'B' condylar head fractures and evaluating the influence of two positional screw distance in two-screw osteosynthesis construct

Clinical fixation screws are common in clinical practices to fix mandibular condyle fractures. Evidence suggests significance of 'working length' that is, distance between proximal and distal fixation screws in proximity to the fracture in orthopaedic implant design. In pursuit of stable implant-bone construct, this study aims to investigate the biomechanical performance of each configuration considered in the study and provide an optimal working length between the screws for clinical reference. Finite element models of virtually designed broken condyle as type 'B' were simulated and analysed in ANSYS Workbench. Screws are implanted according to previous literature at five varied distances 'd' maintaining five different ratios with the fracture length 'D'. Based on a literature review, boundary conditions, muscle traction forces and non-linear contacts were assigned to obtain precise results. Each case is considered an individual configuration and von Mises distribution, microstrain in bone, screw-bone interface micromotion and fracture dislocation were evaluated for all these configurations. Stress-shielding phenomenon is observed for maximum von Mises stresses in bone. Microstrain concentration was significant in cancellous bone in the vicinity of the screw around the fracture line. Configurations were compared based on the stress-strain along with micromotion to support the required amount of osseointegration between implant and bone. Presented data from all five conditions supported the assumption that under physiological loading conditions, the D3 configuration provided stability for fracture healing. Further research on screw shapes, diameters and material properties, or investigating the direction of forces within the screws could provide further insight into this topic.

Evaluation of Mandibular Fractures in a German Nationwide Trauma Center Between 2015 and 2017

Introduction

This study analyses the treatment of isolated mandibular fractures between 1.1.2015 and 21.31.2017 at Dortmund General Hospital.

Materials and Methods

Patient documentation and radiological images have been assessed, and a descriptive statistical analysis has been performed.

Results

Three hundred and twenty-eight patients were identified with isolated mandibular fractures (259 male, 69 female). The male-to-female ratio is 3.75: 1. A total of 541 fracture sites have been identified (1.65 fractures/patient). Forty of these were observed in the dentoalveolar region (fracture of the alveolar process, dental injuries), and the other 501 injuries were distributed in the remaining parts of the lower jaw.A detailed analysis of the osteosynthesis implants is provided. A total of 20 serious complications were observed (6% in all primary cases, 4.5% without osseointegrated implants).

Discussion

The demographic data and the anatomical distribution of the fracture sites are comparable with international literature. Dentoalveolar injuries mostly occur in younger patients. The complication rate in this study (4.5%) is below the international data; however, we found a considerably higher rate than in the midfacial region (central midface: 0%, lateral midface: 1.43%). Despite this complication rate, the procedure can be considered safe.

Supplementary information

The online version of this article (10.1007/s12663-021-01513-4).

Craniomaxillofacial trauma in immature dogs–etiology, treatments, and outcomes

Treatment of craniomaxillofacial (CMF) trauma in dogs often requires a multidisciplinary approach and a thorough understanding of the CMF anatomical structures involved. This retrospective study aimed to utilize computed tomography (CT) studies of immature dogs evaluated for CMF trauma and to describe common fracture locations, treatment modalities, and complications, as well as the fracture healing outcomes. The medical records and CT studies of 94 dogs under 1 year of age over a 13-year period were evaluated. The skeletal location of CMF fractures, as well as the severity of displacement and fragmentation of each fracture, was recorded. Case demographic data and trauma etiology were also recorded. Animal bites accounted for the majority of trauma (71.0%). The most likely bone or region to be fractured was the maxillary bones, followed by the molar region of the mandibles. Up to 37 bones or specific regions were fractured in any given patient, with an average of 8.8 ± 3.1 fractured bones or regions per dog. Rostral mandibular trauma was associated with intra-articular fractures of the temporomandibular joint (p = 0.016). Patients sustained concomitant injuries in 32% of the cases. Muzzle therapy was the main treatment performed for most dogs (53.2%), followed by soft tissue closure (47.9%) and selective dental extractions (27.6%). Healing complications were recorded in 71.6% of the dogs, with malocclusion being the most reported complication (55.2%), and associated with dentate mandibular jaw fractures (p = 0.05). The average number of complications per dog was 2.4. No statistically significant association was found between treatment modality and healing outcome. There was a positive correlation between the severity of fracture fragmentation and displacement and a negative healing outcome (all rho >0.7). Further treatment was required in 55.6% of the dogs. Additional dental extractions were performed in 77.7% of patients. Healing complications were common in the immature CMF trauma case. Thus, the need for a comprehensive assessment of the entire CMF region during the initial visit, as well as follow-up, preferably using CT or cone beam CT, is underscored.

Detection and classification of mandibular fracture on CT scan using deep convolutional neural network

OBJECTIVES

This study aimed to evaluate the accuracy and reliability of convolutional neural networks (CNNs) for the detection and classification of mandibular fracture on spiral computed tomography (CT).

MATERIALS AND METHODS

Between January 2013 and July 2020, 686 patients with mandibular fractures who underwent CT scan were classified and annotated by three experienced maxillofacial surgeons serving as the ground truth. An algorithm including two convolutional neural networks (U-Net and ResNet) was trained, validated, and tested using 222, 56, and 408 CT scans, respectively. The diagnostic performance of the algorithm was compared with the ground truth and evaluated by DICE, accuracy, sensitivity, specificity, and area under the ROC curve (AUC).

RESULTS

One thousand five hundred six mandibular fractures in nine subregions of 686 patients were diagnosed. The DICE of mandible segmentation using U-Net was 0.943. The accuracies of nine subregions were all above 90%, with a mean AUC of 0.956.

CONCLUSIONS

CNNs showed comparable reliability and accuracy in detecting and classifying mandibular fractures on CT.

CLINICAL RELEVANCE

The algorithm for automatic detection and classification of mandibular fractures will help improve diagnostic efficiency and provide expertise to areas with lower medical levels.

Simple dentate area fractures of the mandible - can we prevent postoperative infections?

OBJECTIVE

To evaluate the occurrence of surgical site infections and predisposing factors for these in simple mandibular fractures.

MATERIAL AND METHODS

A retrospective study of patients with fractures of the dentate part of the mandible included patients with intraorally treated simple fractures of the mandibular body, symphysis, and parasymphysis. The primary outcome variable was postoperative surgical site infection. Use of antibiotics, injury mechanism, fracture and surgery-related explanatory variables, patient-related variables and level of oral hygiene according to the modified Total Dental Index were evaluated.

RESULTS

Of 254 patients with mandibular fractures, 107 were included in the final analysis. The infection group consisted of 18 patients (16.8%). Despite the high infection occurrence, significant differences were not found between antibiotic use or other studied variables and infection occurrence. Infections occurred mainly in patients without any specific explanatory factor for infection.

CONCLUSION

The notably high occurrence of surgical site infections despite antibiotic use after simple mandibular fracture surgery highlights the importance of perioperative tissue handling and local oral circumstances. It is also necessary to consider whether we generally accept the high risk of infection associated with the intraorally treated simple mandibular fractures.

Effect of oral exercises and photobiomodulation therapy in the rehabilitation of patients with mandible fractures: randomized double-blind clinical trial

Mandible fractures compromise stomatognathic functions, requiring rehabilitation. Evaluate the effectiveness of photobiomodulation (PBM) associated with oral exercises for rehabilitation of patients with mandible fractures. In this randomized clinical trial, we compared PBM with PBM sham in 14 adults with mandibular fractures who underwent surgical intervention. The sessions were performed 24 h and 48 h after surgical procedure, and weekly for 4 weeks after hospital discharge. Both groups performed oral exercises after each PBM session. Restriction of food consistencies, mandibular mobility, pain, and facial sensitivity measured before and after the surgical procedure were the outcomes evaluated, one and 3 months after surgery. Maximum interincisal distances (MID), exercise pain, and restriction of food consistencies were also evaluated during each week of intervention. Both groups showed normal MID (> 35 mm) and food consistencies consumed 1 month after the surgical procedure, with no significant differences between them. Individuals in the PBM group had less pain response to exercise during all the weeks of intervention than the sham group (p < 0.05). The patients presented a reduction in the painful response in MID and mandibular laterality movements 1 month after surgery compared to the preoperative period. In contrast, there was an improvement in laterality in the sham group only 3 months postoperatively and persistent pain in MID. There was no significant difference in facial sensitivity within and between groups during follow-up. The performance of oral exercises associated with PBM effectively facilitated the early rehabilitation of oral functions, with significant gains in pain management.

Evaluation of Panfacial Fractures in a German Supraregional Trauma Center between 2015 and 2017 - A Retrospective Study

Introduction:

Panfacial fractures represent the most severe injuries to the face. The combination of these fractures determines the treatment strategy. This study aims to retrospectively review the data of adult patients treated for complex facial skull fractures in a hospital in Dortmund, Germany from 2015-2017.

Materials and Methods:

We extracted related patient data from the hospital electronic repository and reviewed the patient files and radiological images. The fractures were classified based on the AO-Classification. The statistical analysis was performed by descriptive statistical methods. The main goal was to determine the most common fracture combinations.

Results:

A total of 188 patients with panfacial fractures were identified (181 adults, 7 children and adolescents). The gender and age distribution corresponded to the international literature (male-to-female ratio: 3.1:1, most common injuries among young men). 2–9 fracture sites were identified per patient, resulting in a fracture frequency of 3.13 per patient. 69 different fracture combinations have been identified. The most common ones were combinations of lateral and central mid-face fractures, and combinations of nasal bone fractures with lateral midface fractures or nasal bone fractures combined with mandibular fractures. Between 1 and 13 osteosynthesis implants per patient were used for osteosynthesis; the most commonly used plates were 2.0 mm and 1.5 mm straight plates. The average inpatient stay was 3 days (standard deviation [SD] = 3.0 days), and the average operation time (incision to suture) was 39.5 min (SD = 53.5 min).

Discussion:

Panfacial fractures are the most complex maxillofacial injuries. The complication rate in this study (4.5%) is below the international data. The treatment of panfacial fractures requires designated centers with experienced teams and good interdisciplinary cooperation.

Complications after osteosynthesis of craniofacial fractures-an analysis from the years 2015-2017

BACKGROUND

Complications mean a recurring problem in everyday clinical practice. Complication rates between 6 and 13% are described for the treatment of bony injuries to the head and neck area. This paper aims to provide a detailed analysis of the complications after osteosynthesis in facial skull fractures.

MATERIAL AND METHOD

In this retrospective study, we reviewed all patient records of injured treated in the Department of Cranial and Maxillofacial Surgery at the Dortmund General Hospital between 2015 and 2017.

RESULTS

Of the 22,031 head and neck injuries, 685 were treated with osteosynthesis. A clinically significant complication was reported in 32 patients (4.76%). The number of total complications was 63. In total, 66.7% of all complications have been identified in the paramedian mandible (44%), median mandible, mandibular angle, and in the collar area (each 12.7%). Eleven implants (in 5 patients) showed a cancellous bone impaction. Broken implants have been recognized in two cases. In 8 cases, there was a pseudarthrosis in the fracture area; in one case, there was a broken implant and pseudarthrosis in combination.

CONCLUSION

Osteosynthesis is a safe method of treating facial skull fractures, which is why we consider it the gold standard of therapy. The complication rate is well below 5%. The 3-dimensional adaptation (bending) and shortening of the osteosynthesis implants do not lead to an increase in complications.

Craniomaxillofacial Trauma in Dogs-Part II: Association Between Fracture Location, Morphology and Etiology

Treatment of craniomaxillofacial (CMF) trauma in dogs requires a thorough understanding of the CMF skeletal structures involved. The human medical literature has several examples of CMF trauma and fracture classification, including the classically described Le Fort fractures. The recent classification schemes require large studies using computed tomography (CT). In the veterinary medical literature, such studies are lacking. The aims of part II of this retrospective study were to use a large number of CT studies of dogs evaluated for CMF trauma to determine whether specific fracture locations in the CMF region occur concurrently, and whether trauma etiology influences fracture morphology. This information may then be used to form a fracture classification scheme in the future. The medical records and CT studies of 165 dogs over a 10-year period were evaluated. The skeletal location of CMF fractures as well as the severity of displacement and fragmentation of each fracture was recorded. Dogs' demographic data and trauma etiology were also recorded. Fractured portions of the mandible tended to occur with fractures of adjacent bones, with the major exception of symphyseal separation, which occurred simultaneously with fractures of the cribriform plate. Fractures of the maxillary bone were accompanied by many concurrent fractures affecting the majority of the midface, skull base, and cranial vault. When the zygomatic bone was fractured, the other bones comprising the orbit also tended to fracture. Fractures of the relatively superficially located frontal and nasal bones were often accompanied by fractures of the skull base. Fracture etiology influenced fracture morphology such that vehicular trauma resulted in a relatively higher number of severely displaced and comminuted fractures than did other trauma etiologies. This study provides examples of fractures that, when found, should prompt veterinarians to look for additional injuries in specific locations. In addition, it further highlights the need for thorough CT evaluation of the entire CMF region, even when clinically apparent fractures appear relatively superficial.

Craniomaxillofacial Trauma in Dogs-Part I: Fracture Location, Morphology and Etiology

Treatment of craniomaxillofacial (CMF) trauma in dogs often requires a multidisciplinary approach and a thorough understanding of the CMF skeletal structures involved. The aim of this retrospective study was to use a large number of CT studies of dogs evaluated for CMF trauma and to describe fracture location and morphology in relation to demographic data and trauma etiology. The medical records and CT studies of 165 dogs over a 10-year period were evaluated. The skeletal location of CMF fractures as well as the severity of displacement and fragmentation of each fracture was recorded. Patient demographic data and trauma etiology were also recorded. Animal bites accounted for the majority of trauma (50%), followed by unknown trauma (15%), vehicular accidents (13%), and blunt force trauma (13%). Small dogs, <10 kg, and juveniles accounted for the majority of patients (41.8 and 25.5%, respectively). The most likely bone or region to be fractured was the maxillary bone, followed by the premolar and molar regions of the mandible. Up to 37 bones or regions were fractured in any given patient, with an average of 8.2 fractured bones or regions per dog. The most commonly fractured location varied according to trauma etiology. Specifically, vehicular accidents tended to result in more locations with a higher probability of fracture than other trauma types. A major conclusion from this study is that every bone of the CMF region was fractured in at least one case and many cases had a large number of fractured regions. Thus, the need for comprehensive assessment of the entire CMF region, preferably using CT, is underscored.

Imaging of mandibular fractures: a pictorial review

Mandibular fractures are among the most common maxillofacial fractures observed in emergency rooms and are mainly caused by road accidents. The clinical features of mandibular fractures include malocclusion and loss of mandibular function. Panoramic radiography is usually limited to isolated lesions, whereas computed tomography is the tool of choice for all other facial traumatic events. No reference standard classification system for the different types of mandibular fractures is defined. Therapeutic options include a conservative approach or surgical treatment based on the anatomic area and the severity of fracture. The main purpose of this pictorial review is to illustrate a practical description of the pathophysiology of mandibular fractures and describe both the imaging techniques to recognise them and the therapeutic indications.

Osteosynthesis of segmental alveolar fractures by internal fixation and the prognosis of the fractures and teeth

BACKGROUND/AIMS

Fracture of the alveolar process is a common injury, but the traditional splinting fixation may not be possible in some cases. The aim of this study was to describe the osteosynthesis performed in segmental alveolar fractures by internal fixation and evaluate the prognosis of the fractures and teeth involved.

MATERIALS AND METHODS

Twenty-two patients who were identified as having segmental alveolar fractures treated with osteosynthesis by internal fixation at the authors' department from January 2007 to December 2016 were included with 90 traumatized teeth. The prognosis of the fractures and teeth involved in the fractures was evaluated by the post-operative computed tomography combined with a follow-up study.

RESULTS

All patients achieved healing and consolidation of the alveolar fractures. Furthermore, the occlusion was restored and the wounds healed. During the surgical procedures, no observed iatrogenic dental damage caused by the interdental drilling was found. Eventually, only 15.6% of the teeth had pulp necrosis, whereas the other healing complications were rare or not observed in the study.

CONCLUSIONS

Osteosynthesis by internal fixation is an effective and safe treatment for some segmental alveolar fractures. The teeth involved in these fractures also have good prognosis.

The Comprehensive AO CMF Classification System for Mandibular Fractures: A Multicenter Validation Study

The AO CMF has recently launched the first comprehensive classification system for craniomaxillofacial (CMF) fractures. The AO CMF classification system uses a hierarchical framework with three levels of growing complexity (levels 1, 2, and 3). Level 1 of the system identifies the presence of fractures in four anatomic areas (mandible, midface, skull base, and cranial vault). Level 2 variables describe the location of the fractures within those defined areas. Level 3 variables describe details of fracture morphology such as fragmentation, displacement, and dislocation. This multiplanar radiographic image-based AO CMF trauma classification system is constantly evolving and beginning to enter worldwide application. A validation of the system is mandatory prior to a reliable communication and data processing in clinical and research environments. This interobserver reliability and accuracy study is aiming to validate the three current modules of the AO CMF classification system for mandible trauma in adults. To assess the performance of the system at the different precision levels, it focuses on the fracture location within the mandibular regions and condylar process subregions as core components giving only secondary attention to morphologic variables. A total of 15 subjects individually assigned the location and features of mandibular fractures in 200 CT scans using the AO CMF classification system. The results of these ratings were then statistically evaluated for interobserver reliability by Fleiss' kappa and accuracy by percentage agreement with an experienced reference assessor. The scores were used to determine if the variables of levels 2 and 3 were appropriate tools for valid classification. Interobserver reliability and accuracy were compared by hierarchy of variables (level 2 vs. level 3), by anatomical region and subregion, and by assessor experience level using Kruskal-Wallis and Wilcoxon's rank-sum tests. The AO CMF classification system was determined to be reliable and accurate for classifying mandibular fractures for most levels 2 and 3 variables. Level 2 variables had significantly higher interobserver reliability than level 3 variables (median kappa: 0.69 vs. 0.59, p  < 0.001) as well as higher accuracy (median agreement: 94 vs. 91%, p  < 0.001). Accuracy was adequate for most variables, but lower reliability was observed for condylar head fractures, fragmentation of condylar neck fractures, displacement types and direction of the condylar process overall, as well as the condylar neck and base fractures. Assessors with more clinical experience demonstrated higher reliability (median kappa high experience 0.66 vs. medium 0.59 vs. low 0.48, p  < 0.001). Assessors with experience using the classification software also had higher reliability than their less experienced counterparts (median kappa: 0.76 vs. 0.57, p  < 0.001). At present, the AO CMF classification system for mandibular fractures is suited for both clinical and research settings for level 2 variables. Accuracy and reliability decrease for level 3 variables specifically concerning fractures and displacement of condylar process fractures. This will require further investigation into why these fractures were characterized unreliably, which would guide modifications of the system and future instructions for its usage.

Digital diagnosis and treatment of mandibular condylar fractures based on Extensible Neuro imaging Archive Toolkit (XNAT)

Objectives

The treatment of condylar fractures has long been controversial. In this paper, we established a database for accurate measurement, storage, management and analysis of patients’ data, in order to help determine the best treatment plan.

Methods

First of all, the diagnosis and treatment database was established based on XNAT, including 339 cases of condylar fractures and their related information. Then image segmentation, registration and three-dimensional (3D) measurement were used to measure and analyze the condyle shapes. Statistical analysis was used to analyze the anatomical structure changes of condyle and the surrounding tissues at different stages before and after treatment. The processes of condylar fracture reestablishment at different stages were also dynamically monitored. Finally, based on all these information, the digital diagnosis and treatment plans for condylar fractures were developed.

Results

For the patients less than 18 years old with no significant dislocation, surgical treatment and conservative treatment were equally effective for intracapsular fracture, and had no significant difference for neck and basal fractures. For patients above 18 years old, there was no significant difference between the two treatment methods for intracapsular fractures; but for condylar neck and basal fractures, surgical treatment was better than conservative treatment. When condylar fracture shift angle was greater than 11 degrees, and mandibular ramus height reduction was greater than 4mm, the patients felt the strongest pain, and their mouths opening was severely restricted. There were 170 surgical cases with condylar fracture shift angel greater than 11 degrees, and 118 of them (69.4%) had good prognosis, 52 of them (30.6%) had complications such as limited mouth opening. There were 173 surgical cases with mandibular ramus height reduction more than 4mm, and 112 of them (64.7%) had good prognosis, 61 of them (35.3%) had complications such as limited mouth opening.

Conclusions

The establishment of XNAT condylar fracture database is helpful for establishing a digital diagnosis and treatment workflow for mandibular condylar fractures, providing new theoretical foundation and application basis for diagnosis and treatment of condylar fractures.

An Alternative Method of Intermaxillary Fixation for Simple Pediatric Mandible Fractures

PURPOSE

Mandibular fractures represent a substantial portion of facial fractures in the pediatric population. Pediatric mandibles differ from their adult counterparts in the presence of mixed dentition. Avoidance of injury to developing tooth follicles is critical. Simple mandibular fractures can be treated with intermaxillary fixation (IMF) using arch bars or bone screws. This report describes an alternative to these methods using silk sutures and an algorithm to assist in treating simple mandibular fractures in the pediatric population.

PATIENTS AND METHODS

A retrospective chart review was performed and the records of 1 surgeon were examined. Pediatric patients who underwent treatment for a mandibular fracture in the operating room from 2011 to 2015 were identified using Common Procedural Terminology codes. Data collected included age, gender, type of fracture, type of treatment used, duration of fixation, and presence of complications.

RESULTS

Five patients with a mean age of 6.8 years at presentation were identified. Fracture types were unilateral fractures of the condylar neck (n = 3), bilateral fractures of the condylar head (n = 1), and a unilateral fracture of the condylar head with an associated parasymphyseal fracture (n = 1). IMF was performed in 4 patients using silk sutures, and bone screw fixation was performed in the other patient. No post-treatment complications or malocclusion were reported. Average duration of IMF was 18.5 days.

CONCLUSIONS

An algorithm is presented to assist in the treatment of pediatric mandibular fractures. Silk suture fixation is a viable and safe alternative to arch bars or bone screws for routine mandibular fractures.

The Comprehensive AOCMF Classification System: Midface Fractures - Level 3 Tutorial

This tutorial outlines the details of the AOCMF image-based classification system for fractures of the midface at the precision level 3. The topography of the different midface regions (central midface-upper central midface, intermediate central midface, lower central midface-incorporating the naso-orbito-ethmoid region; lateral midface-zygoma and zygomatic arch, palate) is subdivided in much greater detail than in level 2 going beyond the Le Fort fracture types and its analogs. The level 3 midface classification system is presented along with guidelines to precisely delineate the fracture patterns in these specific subregions. It is easy to plot common fracture entities, such as nasal and naso-orbito-ethmoid, and their variants due to the refined structural layout of the subregions. As a key attribute, this focused approach permits to document the occurrence of fragmentation (i.e., single vs. multiple fracture lines), displacement, and bone loss. Moreover, the preinjury dental state and the degree of alveolar atrophy in edentulous maxillary regions can be recorded. On the basis of these individual features, tooth injuries, periodontal trauma, and fracture involvement of the alveolar process can be assessed. Coding rules are given to set up a distinctive formula for typical midface fractures and their combinations. The instructions and illustrations are elucidated by a series of radiographic imaging examples. A critical appraisal of the design of this level 3 midface classification is made.

The Comprehensive AOCMF Classification System: Mandible Fractures- Level 2 Tutorial

This tutorial outlines the details of the AOCMF image-based classification system for fractures of the mandible at the precision level 2 allowing description of their topographical distribution. A short introduction about the anatomy is made. Mandibular fractures are classified by the anatomic regions involved. For this purpose, the mandible is delineated into an array of nine regions identified by letters: the symphysis/parasymphysis region anteriorly, two body regions on each lateral side, combined angle and ascending ramus regions, and finally the condylar and coronoid processes. A precise definition of the demarcation lines between these regions is given for the unambiguous allocation of fractures. Four transition zones allow an accurate topographic assignment if fractures end up in or run across the borders of anatomic regions. These zones are defined between angle/ramus and body, and between body and symphysis/parasymphysis. A fracture is classified as "confined" as long as it is located within a region, in contrast to a fracture being "nonconfined" when it extents to an adjoining region. Illustrations and case examples of mandible fractures are presented to become familiar with the classification procedure in daily routine.

The Comprehensive AOCMF Classification System: Radiological Issues and Systematic Approach

The AOCMF Classification Group developed a hierarchical three-level craniomaxillofacial (CMF) classification system with increasing level of complexity and details. The basic level 1 system differentiates fracture location in the mandible (code 91), midface (code 92), skull base (code 93), and cranial vault (code 94); the levels 2 and 3 focus on defining fracture location and morphology within more detailed regions and subregions. Correct imaging acquisition, systematic analysis, and interpretation according to the anatomic and surgical relevant structures in the CMF regions are essential for an accurate, reproducible, and comprehensive diagnosis of CMF fractures using that system. Basic principles for radiographic diagnosis are based on conventional plain films, multidetector computed tomography, and magnetic resonance imaging. In this tutorial, the radiological issues according to each level of the classification are described.

The Comprehensive AOCMF Classification System: Fracture Case Collection, Diagnostic Imaging Work Up, AOCOIAC Iconography and Coding

The AO classification system for fractures in the adult craniomaxillofacial (CMF) skeleton is organized in anatomic modules in a 3 precision-level hierarchy with account for an increasing complexity and details. Level-1 is most elementary and identifies no more than the presence of fractures in 4 separate anatomical units: the mandible (code 91), midface (92), skull base (93) and cranial vault (94). Level-2 relates the detailed topographic location of the fractures within defined regions of the mandible, central and lateral midface, internal orbit, endo- and exocranial skull base, and the cranial vault. Level-3 is based on an even more refined topographic assessment and focuses on the morphology - fragmentation, displacement, and bone defects - within specified subregions. An electronic fracture case collection complements the preceding tutorial papers, which explain the features and options of the AOCMF classification system in this issue of the Journal. The electronic case collection demonstrates a range of representative osseous CMF injuries on the basis of diagnostic images, narrative descriptions of the fracture diagnosis and their classification using the icons for illustration and coding of a dedicated software AOCOIAC (AO Comprehensive Injury Automatic Classifier). Ninety four case examples are listed in two tables for a fast overview of the electronic content. Each case can serve as a guide to getting started with the new AOCMF classification system using AOCOIAC software and to employ it in the own clinical practice.