Evaluating osteogenic effects associated with the incorporation of ascorbic acid in mineralized collagen scaffolds

Current treatments for craniomaxillofacial (CMF) defects motivate the design of instructive biomaterials that can promote osteogenic healing of complex bone defects. We report methods to promote in vitro osteogenesis of human mesenchymal stem cells (hMSCs) within a model mineralized collagen scaffold via the incorporation of ascorbic acid (vitamin C), a key factor in collagen biosynthesis and bone mineralization. An addition of 5 w/v% ascorbic acid into the base mineralized collagen scaffold significantly changes key morphology characteristics including porosity, macrostructure, and microstructure. This modification promotes hMSC metabolic activity, ALP activity, and hMSC-mediated deposition of calcium and phosphorous. Additionally, the incorporation of ascorbic acid influences osteogenic gene expression (BMP-2, RUNX2, COL1A2) and delays the expression of genes associated with osteoclast activity and bone resorption (OPN, CTSK), though it reduces the secretion of OPG. Together, these findings highlight ascorbic acid as a relevant component for mineralized collagen scaffold design to promote osteogenic differentiation and new bone formation for improved CMF outcomes.

Outcomes of 35 dogs with craniomaxillofacial osteosarcoma treated with stereotactic body radiation therapy

Canine craniomaxillofacial osteosarcoma (OSA) is most commonly treated surgically; however, in cases where surgery is not feasible or non-invasive treatment is desired, stereotactic body radiation therapy (SBRT) may be elected for local tumour control. In this study, we evaluated 35 dogs treated with SBRT. Nine dogs (26%) had calvarial, seven (20%) had mandibular and 19 (54%) had maxillary OSA. Median time to first event (TFE) was 171 days, and overall median survival time (MST) was 232 days. Site-specific MSTs were 144 days for mandible, 236 days for calvarium and 232 days for maxilla (p = .49). Pulmonary metastatic disease was observed in 12/35 (34%) patients and was detected pre-SBRT in six dogs (17%) and post-SBRT in the remaining six dogs (17%). Eighteen adverse events post-SBRT were documented. Per veterinary radiation therapy oncology group criteria, five were acute (14%) and three were late (9%) grade 3 events. Neurological signs in two dogs were suspected to be early-delayed effects. Cause of death was local progression for 22/35 (63%) patients, metastasis for 9/35 (26%) patients and unknown for four. On univariate analysis, administration of chemotherapy was associated with a longer TFE (p = .0163), whereas volume of gross tumour volume was associated with a shorter TFE (p = .023). Administration of chemotherapy and five fractions versus single fraction of SBRT was associated with increased survival time (p = .0021 and .049). Based on these findings, a treatment protocol incorporating chemotherapy and five fractions of SBRT could be considered for dogs with craniomaxillofacial OSA electing SBRT with careful consideration of normal tissues in the field.

Virtual surgical planning in craniomaxillofacial surgery: a structured review

Craniomaxillofacial (CMF) surgery is a challenging and very demanding field that involves the treatment of congenital and acquired conditions of the face and head. Due to the complexity of the head and facial region, various tools and techniques were developed and utilized to aid surgical procedures and optimize results. Virtual Surgical Planning (VSP) has revolutionized the way craniomaxillofacial surgeries are planned and executed. It uses 3D imaging computer software to visualize and simulate a surgical procedure. Numerous studies were published on the usage of VSP in craniomaxillofacial surgery. However, the researchers found inconsistency in the previous literature which prompted the development of this review. This paper aims to provide a comprehensive review of the findings of the studies by conducting an integrated approach to synthesize the literature related to the use of VSP in craniomaxillofacial surgery. Twenty-nine related articles were selected as a sample and synthesized thoroughly. These papers were grouped assigning to the four subdisciplines of craniomaxillofacial surgery: orthognathic surgery, reconstructive surgery, trauma surgery and implant surgery. The following variables - treatment time, the accuracy of VSP, clinical outcome, cost, and cost-effectiveness - were also examined. Results revealed that VSP offers advantages in craniomaxillofacial surgery over the traditional method in terms of duration, predictability and clinical outcomes. However, the cost aspect was not discussed in most papers. This structured literature review will thus provide current findings and trends and recommendations for future research on the usage of VSP in craniomaxillofacial surgery.

Bioactive Scaffolds as a Promising Alternative for Enhancing Critical-Size Bone Defect Regeneration in the Craniomaxillofacial Region

Reconstruction of critical-size bone defects (CSDs) in the craniomaxillofacial (CMF) region remains challenging. Scaffold-based bone-engineered constructs have been proposed as an alternative to the classical treatments made with autografts and allografts. Scaffolds, a key component of engineered constructs, have been traditionally viewed as biologically passive temporary replacements of deficient bone lacking intrinsic cues to promote osteogenesis. Nowadays, scaffolds are functionalized, giving rise to bioactive scaffolds promoting bone regeneration more effectively than conventional counterparts. This review focuses on the three approaches most used to bioactivate scaffolds: (1) conferring microarchitectural designs or surface nanotopography; (2) loading bioactive molecules; and (3) seeding stem cells on scaffolds, providing relevant examples of in vivo (preclinical and clinical) studies where these methods are employed to enhance CSDs healing in the CMF region. From these, adding bioactive molecules (specifically bone morphogenetic proteins or BMPs) to scaffolds has been the most explored to bioactivate scaffolds. Nevertheless, the downsides of grafting BMP-loaded scaffolds in patients have limited its successful translation into clinics. Despite these drawbacks, scaffolds containing safer, cheaper, and more effective bioactive molecules, combined with stem cells and topographical cues, remain a promising alternative for clinical use to treat CSDs in the CMF complex replacing autografts and allografts.

CMF-Net: craniomaxillofacial landmark localization on CBCT images using geometric constraint and transformer

Accurate and robust anatomical landmark localization is a mandatory and crucial step in deformation diagnosis and treatment planning for patients with craniomaxillofacial (CMF) malformations. In this paper, we propose a trainable end-to-end cephalometric landmark localization framework on CBCT scans, referred to as CMF-Net, which combines the appearance with transformers, geometric constraint, and adaptive wing (AWing) loss. More precisely: 1) We decompose the localization task into two branches: the appearance branch integrates transformers for identifying the exact positions of candidates, while the geometric constraint branch at low resolution allows the implicit spatial relationships to be effectively learned on the reduced training data. 2) We use the AWing loss to leverage the difference between the pixel values of the target heatmaps and the automatic prediction heatmaps. We verify our CMF-Net by identifying the 24 most relevant clinical landmarks on 150 dental CBCT scans with complicated scenarios collected from real-world clinics. Comprehensive experiments show that it performs better than the state-of-the-art deep learning methods, with an average localization error of 1.108 mm (the clinically acceptable precision range being 1.5 mm) and a correct landmark detection rate equal to 79.28%. Our CMF-Net is time-efficient and able to locate skull landmarks with high accuracy and significant robustness. This approach could be applied in 3D cephalometric measurement, analysis, and surgical planning.

Craniomaxillofacial trauma in war-torn nations: Incidence, management gaps, and recommendations

Craniomaxillofacial trauma (CMFT) is a type of injury that affects the face, neck, and scalp, and includes facial bone fractures, dentoalveolar trauma, and soft tissue injuries. Work, traffic accidents, sports, and daily activities commonly cause these injuries. However, they are widespread in war-torn countries where armed conflict leads to a high incidence of CMFT. The lack of resources, health care infrastructure, and surgical personnel in these areas result in subpar treatment and poor patient outcomes, contributing to the high mortality and morbidity rates among war victims. The importance of a multidisciplinary approach to CMFT management cannot be overstated, but current obstacles, such as a lack of access to proper medical care and rehabilitation services, impede the development of effective treatments. CMFT treatment is complex and prohibitively expensive for war-torn nations to afford, necessitating international intervention to provide life-saving surgical procedures for those suffering from CMFT in conflict zones. Despite efforts to improve CMFT treatments in war-torn countries, more must be done to improve treatment outcomes. Data collection and research must also be improved in order to develop effective evidence-based treatment methods.

Preliminary Study of the Treatment Strategy for Retaining Traumatic Foreign Bodies Involving the Carotid Artery

PURPOSE

Craniomaxillofacial trauma is usually accompanied by indwelling foreign bodies, and some of those are close to the carotid artery, which increases the risks and difficulties of surgical treatment. The introduction of interventional radiology combined with image-guided surgical navigation may be a good solution for precise surgery to remove foreign bodies.

PATIENTS AND METHODS

Four patients were included in the study. All patients underwent digital subtraction angiography and enhanced computed tomography before surgery. The patients were divided into 3 categories (A, B, and C) according to the presence of carotid artery damage and its positional relationship with the foreign body, and 3 corresponding treatment strategies were developed. Treatments were completed using interventional radiology and surgical navigation systems.

RESULTS

All foreign bodies were completely removed, except for 1 remaining in the jugular foramen in a patient. The prognosis of all patients was good, and no systemic complications occurred.

CONCLUSION

The combined interventional radiology and surgical navigation method proposed in this study is an effective method to improve the accuracy and safety of foreign body removal surgery.

The Global Impact of COVID-19 on Craniomaxillofacial Surgeons: A Follow-Up Survey After One Year

Study Design

Comparative cross-sectional.

Objective

To measure the impact that COrona VIrus Disease-19 (COVID-19) has had on craniomaxillofacial (CMF) surgeons after 1 year and compare it with 2020 data by (1) measuring access to adequate personal protective equipment (PPE), (2) performance of elective surgery, and (3) the vaccination status. This should be investigated because most CMF surgeons felt that hospitals did not provide them with adequate PPE.

Methods

The investigators surveyed the international AO CMF membership using a 30-item online questionnaire and compared it to a previous study. The primary predictor variable was year of survey administration. Primary outcome variables were availability of adequate personal protective equipment (adequate/inadequate), performance of elective surgery (yes/no), and vaccination status (fully vaccinated/partly vaccinated/not vaccinated). Descriptive and analytic statistics were computed. Binary logistic regression models were created to measure the association between year and PPE availability. Statistical significance level was set at P < .05.

Results

The sample was composed of 523 surgeons (2% response rate). Most surgeons reported access to adequate PPE (74.6%). The most adequate PPE was offered in Europe (87.8%) with the least offered in Africa (45.5%). Surgeons in 2021 were more likely to report adequate PPE compared to 2020 (OR 3.74, 95% CI [2.59-4.39]). Most of the respondents resumed elective surgery (79.5% vs 13.3% in 2020) and were fully vaccinated (59.1%).

Conclusions

Most CMF surgeons now have access to adequate PPE, resumed elective surgery, and are either fully or partly vaccinated. Future studies should investigate the long-term impact of the fast-evolving COVID-19 pandemic on CMF surgeons.

Application of zebrafish in the study of craniomaxillofacial developmental anomalies

Craniomaxillofacial developmental anomalies are one of the most prevalent congenital defects worldwide and could result from any disruption of normal development processes, which is generally influenced by interactions between genes and the environment. Currently, with the advances in genetic screening strategies, an increasing number of novel variants and their roles in orofacial diseases have been explored. Zebrafish is recognized as a powerful animal model, and its homologous genes and similar oral structure and development process provide an ideal platform for studying the contributions of genetic and environmental factors to human craniofacial malformations. Here, we reviewed zebrafish models for the study of craniomaxillofacial developmental anomalies, such as human nonsyndromic cleft lip with or without an affected palate and jaw and tooth developmental anomalies. Due to its potential for gene expression and regulation research, zebrafish may provide new perspectives for understanding craniomaxillofacial diseaseand its treatment.

Role of Navigation in Oral and Maxillofacial Surgery: A Surgeon's Perspectives

Surgeries related to the maxillofacial area deal with an intricate network of anatomical structures. With the complexity of the vital structures, it necessitates a surgical team to respect each anatomical boundary. In the past, there was an exceptionally high number of cases with surgical errors. These errors were not because of flaws in the surgeon’s skills or techniques but owing to lack of resources. Visualisation is one of the key factors that determines the precision of any surgical outcome. Advances in surgical planning have led to the introduction of a “Navigation” system that helps surgeons to see more, know more and ultimately do more for their patients. The usefulness of the navigation system in oral surgeries has been indicated by its surgical applications in craniomaxillofacial trauma, orthognathic surgeries, head and neck pathological resections, complex skull base surgeries and surgery involving temporomandibular joint. A vast majority of research literature has suggested remarkable improvement in surgical outcomes under the guidance of 3d planning and navigation. However, with such an inordinate advancement, financial expenses and a gradual learning curve are always a constraining factor in surgical navigation. This article overviews indication of navigation in craniofacial surgeries with a focus on applied aspect, planning and solution to the future problem.

The Global Impact of COVID-19 on Craniomaxillofacial Surgeons

STUDY DESIGN

The COrona VIrus Disease-19 (COVID-19) pandemic has disrupted craniomaxillofacial (CMF) surgeons practice worldwide. We implemented a cross-sectional study and enrolled a sample of CMF surgeons who completed a survey.

OBJECTIVE

To measure the impact that COVID-19 has had on CMF surgeons by (1) identifying variations that may exist by geographic region and specialty and (2) measuring access to adequate personal protective equipment (PPE) and identify factors associated with limited access to adequate PPE.

METHODS

Primary outcome variable was availability of adequate PPE for health-care workers (HCWs) in the front line and surgeons. Descriptive and analytic statistics were computed. Level of statistical significance was set at P < .05. Binary logistic regression models were created to identify variables associated with PPE status (adequate or inadequate).

RESULTS

Most of the respondents felt that hospitals did not provide adequate PPE to the HCWs (57.3%) with significant regional differences (P = .04). Most adequate PPE was available to surgeons in North America with the least offered in Africa. Differences in PPE adequacy per region (P < .001) and per country (P < .001) were significant. In Africa and South America, regions reporting previous virus outbreaks, the differences in access to adequate PPE evaporated compared to Europe (P = .18 and P = .15, respectively).

CONCLUSION

The impact of COVID-19 among CMF surgeons is global and adversely affects both clinical practice and personal lives of CMF surgeons. Future surveys should capture what the mid- and long-term impact of the COVID-19 crisis will look like.

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.

Incidental findings on craniomaxillofacial cone beam computed tomography in orthodontic patients

PURPOSE

Cone beam computed tomography (CBCT) in orthodontics is increasingly used for detecting impacted or ectopic teeth or for orthognathic and cleft lip and palate treatment. Incidental findings (IFs) are frequently encountered and often relevant. The aim of this study was to detect the prevalence of relevant pathologies on CBCT scans of orthodontic patients.

METHODS

Over a 6-year period, incidental imaging findings were analyzed in 345 CBCT scans (181 men; 164 women; age 16.3 ± 8.4 years), and subdivided into dental (Group 1), skeletal (Group 2), sinunasal (Group 3), and infrequent other pathologies (Group 4).

RESULTS

A total of 502 IFs were detected in 345 patients (1.4 IFs per patient, on average). Most IFs were found in Group 1 (358 IFs; 71.3%), followed by Group 2 (129 IFs; 25.7%), Group 3 (14 IFs; 2.8%), and Group 4 (1 IF; 0.2%). There were 119 (34.5%) patients with a missing wisdom tooth, 94 (27.3%) with dental aplasia, 71 (20.6%) with dislocations, 33 (9.6%) with partial opacifications, and 27 (7.8%) with signs of sinusitis.

CONCLUSIONS

This study found that IFs in orthodontic CBCT scans are frequently encountered, even in younger orthodontic patients. When interpreting CBCT scans, orthodontists should be aware of potential relevant IFs that may require further investigation, change patients' treatment or affect their quality of life.

A 14-Year Review of Craniomaxillofacial Gunshot Wounds in a Resource-Limited Setting

This study analyzed the prevalence, clinical characteristics, and management of civilian-type craniomaxillofacial gunshot wounds (CGSWs) seen over a 14-year period in a Northern Nigerian teaching hospital. A retrospective study of all hospital records relating to CGSWs from January 2000 to December 2013 was conducted to determine the prevalence of CGSWs. Information retrieved included site of injury, type of projectile, management protocol, as well as duration of hospitalization. A total of 46 admissions for CGSWs were recorded during the period under review from a total of 2,228 maxillofacial admissions. This gave a prevalence of 2.1% for CGSWs (95% confidence interval = 1.56-2.81). Sex distribution was 14.3:1 (M:F) with overall mean age of 32.9 ± 8.4 years. Average length of hospitalization was 17.7 (±15.56) days. Management of CGSWs consisted of emergency care, preliminary intervention, definitive reconstruction, revisions, and rehabilitation. Conclusively, analysis of the yearly incidence of CGSWs showed that the incidence and severity increased within the past 2 years under review (18 cases, 39.13%; χ² trend = 7.7, p = 0.006). This period was noted to correspond with heightened violence within the region mostly due to the acts of unknown gunmen and insurgents.

Analysis of Practice Settings for Craniofacial Surgery Fellowship Graduates in North America

OBJECTIVE

In North America, the number of craniofacial surgery fellowship graduates is increasing, yet an analysis of practice settings upon graduation is lacking. We characterize the practice types of recent graduates of craniofacial fellowship programs in the United States and Canada.

DESIGN

A 6-year cohort of craniofacial fellows in the United States and Canada (2010-2016) were obtained from craniofacial programs recognized by the American Society of Craniofacial Surgery. Practice setting was determined at 1 and 3 years of postgraduation, and predictors of practice setting were determined.

RESULTS

A total of 175 craniofacial surgeons were trained at 35 fellowship programs. At 1 year of postgraduation, 33.6% had an academic craniofacial position and 27.1% were in private practice (p = 0.361). A minority of graduates pursued additional fellowships (16.4%), nonacademic craniofacial positions (10.0%), academic noncraniofacial positions (5.7%), and international practices (7.1%). At 3 years of postgraduation, the percentage of graduates in academic craniofacial positions was unchanged (34.5% vs 33.6%, p = 0.790). The strongest predictors of future academic craniofacial practice were completing plastic surgery residency at a program with a craniofacial fellowship program (odds ratio = 6.78, p < 0.001) and completing an academic craniofacial fellowship program (odds ratio = 4.48, p = 0.020).

CONCLUSIONS

A minority of craniofacial fellowship graduates practice academic craniofacial surgery. A strong academic craniofacial surgery background during residency and fellowship is associated with a future career in academic craniofacial surgery. These data may assist trainees choose training programs that align with career goals and educators select future academic surgeons.

The Ever-Evolving State of the Art: A Look Back at the AONA Facial Reconstruction and Transplantation Meetings

Historically, periodic academic meetings held by surgical societies have set the stage for discussion and exchange of ideas, which in turn have led to advancement of clinical practices. Since 2007, the AONA State of the Art: Facial Reconstruction and Transplantation Meeting (FRTM) has been organized to provide a forum for specialists around the world to engage in open conversation about the approaches currently at the forefront of facial reconstruction. Review of registration data of FRTM iterations from 2007 to 2015 was performed. The total number of participants, along with their level of medical training, location of practice, and medical specialty, was recorded. Additionally, academic programs and 2015 participant feedback were evaluated. From 2007 to 2011, there was a decrease in the overall number of participants, with a slight increase in the number of clinical specialties present. In 2013, a sharp increase in total participants, international attendance, and represented clinical specialties was observed. This trend continued in 2015. Adjustments to academic programs have included reorganization of lectures and optimization of content. FRTM is a unique forum for multidisciplinary professionals to discuss the evolving field of facial reconstruction and join forces to accelerate progress and improve patient care.

Analysis of an In-Service Examination for Core Pediatric Craniofacial Surgery Knowledge

OBJECTIVE

Little is known about designing an effective residency curriculum for pediatric craniofacial surgery. This study elucidates the pediatric craniofacial curriculum of the Plastic Surgery In-Service Training Examination (PSITE) to facilitate knowledge acquisition during residency.

DESIGN

Approximately, 6 consecutive PSITEs were reviewed for pediatric craniofacial questions (2010-2015). Subjects were categorized according to topics on the American Board of Plastic Surgery written board examination. Questions were categorized using an educational taxonomy model. Answer references were categorized by source and publication lag.

RESULTS

Of 1174 PSITE questions, 147 tested pediatric craniofacial topics (12.5%). Questions appeared predominately in the Craniomaxillofacial section (83.0%, p < 0.001). The annual representation was stable more than 6 years (range: 10.2%-14.4%, p = 0.842). Question taxonomy favored interpretation (45.6%) and decision-making (40.8%) over recall (13.6%, p < 0.001) skills, and 41 questions had an associated image (27.9%) and most were photographic (76.7%, p < 0.001). The most frequently tested categories on the American Board of Plastic Surgery written examination content outline were craniofacial anomalies (23.5%), benign and malignant tumors (17.6%), and cleft lip and palate (12.5%). Overall, 80 unique journals were cited 304 times with a mean publication lag of 9.4 ± 10.9 years. Plastic and Reconstructive Surgery (34.5%) was the most cited journal (p < 0.001).

CONCLUSIONS

These data may assist in designating core knowledge competency in pediatric craniofacial surgery for plastic surgery residents. A further understanding of PSITE utility for core knowledge competency in pediatric craniofacial surgery would be the focus of future work.

The primal sagittal plane of the head: a new concept

To assess facial form, one has to determine the size, position, orientation, shape, and symmetry of the different facial units. Many of these assessments require a frame of reference. The customary coordinate system used for these assessments is the 'standard anatomical frame of reference', a three-dimensional Cartesian system made by three planes: the sagittal, the axial, and the coronal. Constructing the sagittal plane seems simple, but because of universal facial asymmetry, it is complicated. Depending on the method one selects, one can build hundreds of different planes, never knowing which one is correct. This conundrum can be solved by estimating the sagittal plane a patient would have had if his or her face had developed symmetrically. We call this the 'primal sagittal plane'. To estimate this plane we have developed a mathematical algorithm called LAGER (Landmark Geometric Routine). In this paper, we explain the concept of the primal sagittal plane and present the structure of the LAGER algorithm.

The First AO Classification System for Fractures of the Craniomaxillofacial Skeleton: Rationale, Methodological Background, Developmental Process, and Objectives

Validated trauma classification systems are the sole means to provide the basis for reliable documentation and evaluation of patient care, which will open the gateway to evidence-based procedures and healthcare in the coming years. With the support of AO Investigation and Documentation, a classification group was established to develop and evaluate a comprehensive classification system for craniomaxillofacial (CMF) fractures. Blueprints for fracture classification in the major constituents of the human skull were drafted and then evaluated by a multispecialty group of experienced CMF surgeons and a radiologist in a structured process during iterative agreement sessions. At each session, surgeons independently classified the radiological imaging of up to 150 consecutive cases with CMF fractures. During subsequent review meetings, all discrepancies in the classification outcome were critically appraised for clarification and improvement until consensus was reached. The resulting CMF classification system is structured in a hierarchical fashion with three levels of increasing complexity. The most elementary level 1 simply distinguishes four fracture locations within the skull: mandible (code 91), midface (code 92), skull base (code 93), and cranial vault (code 94). Levels 2 and 3 focus on further defining the fracture locations and for fracture morphology, achieving an almost individual mapping of the fracture pattern. This introductory article describes the rationale for the comprehensive AO CMF classification system, discusses the methodological framework, and provides insight into the experiences and interactions during the evaluation process within the core groups. The details of this system in terms of anatomy and levels are presented in a series of focused tutorials illustrated with case examples in this special issue of the Journal.