The Identification of Mandible Fractures by Helical Computed Tomography and Panorex Tomography

Temporomandibular joint degenerative changes following mandibular fracture: a computed tomography-based study on the role of condylar involvement

OBJECTIVES

This study assessed the incidence of postfracture radiological temporomandibular joint (TMJ) degeneration in patients with different types of mandibular fractures, focusing on the impact of condylar fractures.

METHODS

This retrospective review included patients diagnosed as having mandibular fractures from 2016 to 2020 who had undergone initial computed tomography (CT) and a follow-up CT scan at least 1-month postfracture. Patient demographics, fracture details, treatment methods, and radiological signs of TMJ degeneration on CT were analyzed to identify risk factors for postfracture TMJ degeneration, with a focus on condylar head fracture and non-head (condylar neck or base) fractures.

RESULTS

The study included 85 patients (mean age: 38.95 ± 17.64 years). The per-patient analysis indicated that the incidence of new radiologic TMJ degeneration on CT was significantly the highest (p < 0.001) in patients with condylar head fractures (90.91%), followed by those with non-head condylar fractures (57.14%), and those without condylar involvement (24.49%). The per-joint analysis indicated nearly inevitable degeneration (93.94%) in 33 TMJs with ipsilateral condylar head fractures. For the remaining 137 TMJs, multivariate logistic regression revealed that other patterns (ipsilateral non-head, contralateral, or both) of condylar fractures (odds ratio (OR) = 3.811, p = 0.007) and the need for open reduction and internal fixation (OR = 5.804, p = 0.005) significantly increased the risk of TMJ degeneration.

CONCLUSIONS

Ipsilateral non-head condylar fractures and contralateral condylar fractures are associated with a high risk of postfracture TMJ degeneration. Indirect trauma plays a vital role in postfracture TMJ degeneration.

The Application of Cone Beam Computed Tomography (CBCT) on the Diagnosis and Management of Maxillofacial Trauma

The assessment and management of facial trauma in an acute setting is one of the core services provided by oral and maxillofacial units in the United Kingdom. Imaging is a pre-requisite for appropriate diagnosis and treatment planning, with a combination of plain radiographs and medical-grade CT being the mainstay. However, the emergence of cone beam CT in recent years has led to its wider applications, including facial trauma assessment. It can offer multi-planar reformats and three-dimensional reconstruction at a much lower radiation dose and financial cost than conventional CT. The purpose of this review is to appraise its potential indications in all anatomical areas of maxillofacial trauma and provide our experience at a level 1 trauma centre.

Applications of Preoperative and Intraoperative Technologies for Complex Primary and Secondary Facial Trauma Reconstruction

This article provides a review of the current technologies available in the preoperative and intraoperative management of complex and secondary maxillofacial trauma reconstruction. These patients present a unique challenge for which the advancement of imaging technologies, patient-specific modeling and implants, and intraoperative imaging and navigation can play an important role to improve their post-treatment outcomes.

Diagnosis of split fractures of the mandible in adults

BACKGROUND

Mandibular split fractures, in which the fracture occurs exclusively in the posterior wall, are uncommon. This study aimed to enhance clinicians' understanding of mandibular split fractures and offer insights for future research.

METHODS

This study included six patients who visited our hospital between January 2020 and June 2023 and were diagnosed with mandibular split fractures. We retrospectively collected data from patients' medical records on their age, sex, symptoms, mechanism, impact site, associated injuries, and treatment method, as well as the location, pattern, and number of fractures observed on computed tomography (CT) and panoramic images. The frequency of split fractures among all mandibular fractures was calculated.

RESULTS

The six patients included three men (50%) and three women (50%), ranging in age from 20 to 71 years (mean age, 49.8 years). The split fractures were located in the symphysis in one patient (16.7%), symphysis to parasymphysis in two patients (33.3%), parasymphysis in one patient (16.7%), and parasymphysis to the body in two patients (33.3%). Four patients (66.7%) had condylar head fractures, while two patients (33.3%) had single split fractures. The mechanism of trauma was a slip-down incident in four cases (66.7%), while two cases (33.3%) were caused by motorcycle traffic accidents. Four patients (67%) underwent intermaxillary fixation, while two patients (33%) improved with conservative treatment. Split fractures were diagnosed in all six patients on CT, whereas the fracture line was not clearly visible on panoramic images. Mandibular split fractures accounted for 5.6% of all mandibular fractures.

CONCLUSION

This study provides insights into the clinical characteristics of rare mandibular split fractures and the diagnostic imaging findings. Furthermore, CT scans and three-dimensional image synthesis-instead of panoramic images-may be essential for accurately diagnosing mandibular fractures, including mandibular split fractures, in the future.

ACR Appropriateness Criteria® Imaging of Facial Trauma Following Primary Survey

Maxillofacial trauma patients comprise a significant subset of patients presenting to emergency departments. Before evaluating for facial trauma, an emergency or trauma physician must perform a primary survey to ensure patient stabilization. Following this primary survey, this document discusses the following clinical scenarios for facial trauma: tenderness to palpation or contusion or edema over frontal bone (suspected frontal bone injury); pain with upper jaw manipulation or pain overlying zygoma or zygomatic deformity or facial elongation or malocclusion or infraorbital nerve paresthesia (suspected midface injury); visible nasal deformity or palpable nasal deformity or tenderness to palpation of the nose or epistaxis (suspected nasal bone injury); and trismus or malocclusion or gingival hemorrhage or mucosal hemorrhage or loose teeth or fractured teeth or displaced teeth (suspected mandibular injury). The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Re-evaluating the need for orthopantomography in the management of mandibular trauma: is computed tomography enough?

BACKGROUND

Mandibular fractures are frequent indications for computed tomography (CT) and orthopantomography (OPG) scans in emergency rooms. Numerous studies found CT to have higher sensitivity and enhanced accuracy compared to OPG in diagnosing mandible fractures. Controversy exists regarding additional need for OPG when evaluating dental trauma. This study investigates whether OPG adds diagnostic value to CT in mandibular trauma and whether additional OPG significantly alters management.

METHODS

A retrospective chart review identified 100 patients ≥ 18 years of age with known mandibular trauma who received CT and OPG in the emergency department between May 2015 and January 2020. All patients demonstrated a fracture in at least one study. CT and OPG studies were anonymized and randomized. A single attending surgeon evaluated mandible fracture and dental trauma characteristics and subsequently compared findings.

RESULTS

One hundred patient CT and OPG scans were reviewed. CT detected mandible fractures in all patients and OPG detected fractures in 93% (p = 0.01). Twenty-eight patients had different findings between scans. CT demonstrated 1 or more additional fracture(s) than OPG in 20 patients and dental trauma not seen on OPG in 4. OPG detected 1 fracture and no dental trauma that was not seen on CT. CT drove treatment-determining differences in 17 cases and OPG in 0 cases.

CONCLUSIONS

CT appears efficacious in detecting clinically significant mandible fractures and dental trauma with little additional benefit from OPG in emergency settings. Helical CT may be the only imaging necessary in evaluating patients with such trauma.

Radiological investigation of acute mandibular injury

This article focuses on the different imaging modalities used to evaluate acute mandibular fractures and explores important concepts relating to their diagnosis, investigation, and treatment. Significant focus will be given to exploring general management principles, considerations regarding first-line imaging, and recent technological advancement. Computed tomography (CT) is the preferred method when attempting to identify acute mandibular fractures, particularly in trauma patients, and has very high specificity and sensitivity. Multidetector CT now represents the standard of care, enabling fast scan times, reduced artifact, accurate reconstructed views, and three-dimensional (3D) reconstructions. Cone-beam CT is a newer advanced imaging modality that is increasingly being used worldwide, particularly in the ambulatory and intraoperative setting. It produces high-resolution images with submillimeter isotropic voxels, 3D and multiplanar reconstruction, and low radiation dose, however is less widely available and more expensive. Ultrasound is a valuable method in identifying a fracture in unstable patients, but is limited in its ability to detect nondisplaced fractures. Magnetic resonance imaging is useful in determining the presence of soft-tissue injury. CT angiography is invaluable in the assessment of potential vascular injury in condylar fracture dislocations.

Mandibular Body Fractures

Fractures of the mandibular body most commonly occur after interpersonal violence or motorized vehicle accident but can occur in athletes. Mandibular body fractures are often associated with additional mandibular fractures. The treatment goal is to achieve preinjury occlusion and facial appearance, and this can be done via a closed reduction and maxillomandibular fixation or open reduction and fixation with or without maxillomandibular fixation. The authors present 3 cases in this article.

Does Intraoperative Computed Tomography Scanning in Maxillofacial Trauma Surgery Affect the Revision Rate?

PURPOSE

The purpose of this study was to determine how intraoperative computed tomography affects the intraoperative revision rate and consequently the post-operative, secondary corrective surgery in maxillofacial trauma surgeries.

PATIENTS AND METHODS

A retrospective study composed of patients with facial fractures was conducted in Prince Sultan Military Medical City in Riyadh, Saudi Arabia. The predictor variables were age, gender, site of facial fracture, type of treatment, number of scans per patient, and discharge time. The primary outcome variable was immediate intraoperative revision rate. Secondary outcome variable was total scanning time (recorded from the moment surgery was halted until it was resumed after image acquisition). Descriptive statistics were used; numerical data presented as mean ± SD and categorical variables as frequency (%).

RESULTS

A total of 22 patients underwent 25 intraoperative scans while undergoing different maxillofacial surgeries. Eleven (50%) required intraoperative revisions after the scans, and 3 (13.6%) cases had another intraoperative scan after revision. Eighteen were men and 4 were women. The mean age was 30 years and age range was 19 to 76. Cases were categorized by fracture location and treatment preformed. The mean scanning time was 18.9 ± 4.6 minutes. The highest rate of revisions was seen in zygomaticomaxillary complex fractures (63.6%), they were also the only cases that required a second intraoperative scan after revision to confirm final reduction. No complications were seen postoperatively, and all patients recovered uneventfully. None of the patients required a secondary corrective surgery. All patients were discharged on the following day, except 1 case which was admitted under another service.

CONCLUSIONS

The use of intraoperative computed tomography imaging in treating maxillofacial fractures results in a higher rate of intraoperative revisions, which in turn leads to more accurate fracture reduction and consequently reduces the possibility of a postoperative, secondary corrective surgery.

Paediatric mandibular fracture-a diagnostic challenge?

The purpose of this study was to clarify the frequency of missed mandibular fractures and to identify possible predictive factors for missed diagnosis. This was a retrospective study that included patients <20 years of age with a recent mandibular fracture. The outcome variable was missed mandibular fracture, which was determined when a fracture was not suspected or diagnosed during the patient's first assessment in primary healthcare. The primary predictor variable was age group (i.e. children <13 years or teenagers/adolescents aged 13-19 years). The explanatory variables were sex, mechanism of injury, and type of facial facture. Other variables were clinical symptoms and findings. Mandibular fracture was missed at first contact in 27 of 182 patients (14.8%). Fracture was missed significantly more often in patients <13 years than in older patients (33.3% vs. 8.8%, P<0.001). The only significant symptom or clinical finding that was associated with missed fractures was skin wound of the jaw (P=0.009). There was no association between missed fracture and sex or mechanism of injury. Mandibular fractures in children are often missed at the first healthcare contact. Careful examination is necessary in paediatric mandibular injuries, particularly in the youngest age groups. Consultation should be smooth between paediatric trauma units and maxillofacial surgeons.

Facial fractures: classification and highlights for a useful report

In patients with facial trauma, multidetector computed tomography is the first-choice imaging test because it can detect and characterize even small fractures and their associated complications quickly and accurately. It has helped clinical management and surgical planning, so radiologists must communicate their findings to surgeons effectively. In Le Fort fractures, there is a breach between the pterygoid plates and the posterior maxilla. These fractures are classified in three basic patterns that can be combined and associated with various complications. Conceptualized when low-speed trauma was predominant, the Le Fort classification system has become less relevant giving more importance on maxillary occlusion-bearing segments. The classification of naso-orbito-ethmoid depends on the extent of injury to the attachment of the medial canthal tendon, with possible complications like nasofrontal duct disruption. Displaced fractures of the zygomaticomaxillary complex often widen the angle of the lateral orbital wall, resulting in increased orbital volume and sometimes in enophthalmos. Severe comminution or angulation can lead to wide surgical exposure. In orbital fractures, entrapment of the inferior rectus muscles can lead to diplopia, so it is important to assess its positioning and morphology. Orbital fractures can also result in injuries to the globe or infraorbital nerve. Frontal sinus fractures that extend through the posterior sinus wall can create a communication with the anterior cranial fossa resulting in leakage of cerebrospinal fluid, intracranial bleeding. It is essential to categorize fracture patterns and highlight features that may affect fracture management in radiology reports of facial trauma.

The Diagnosis and Management of Facial Bone Fractures

Appropriate medical care for a patient with a facial fracture can not only optimize aesthetic outcomes but also prevent the potential morbidity and mortality of delayed treatment. In this article, we focus on the clinical presentations, physical examination findings, diagnostic imaging, consultations, and follow-up that patients with facial fractures need related to their emergency department management. Specifically, we address the nuances of evaluating frontal, orbital, nasal, maxillofacial, and mandibular fractures.

Management of Zygomaticomaxillary Complex Fractures

Zygomaticomaxillary fractures account for approximately 25% of all facial fractures. They can be grouped into high-velocity and low-velocity injuries. A complete head and neck examination is critical for accurate clinical diagnosis. A thin-cut axial CT scan with sagittal, coronal, and 3-D reconstruction is important for accurate diagnosis and treatment planning. A thorough understanding of bony tetrapod anatomy and fracture mechanics is critical to treatment planning. Treatment options include closed and open reduction with internal fixation. Computer-aided applications can reduce the need for open reduction and improve the accuracy of both closed and open repairs.

Multidetector CT of Mandibular Fractures, Reductions, and Complications: A Clinically Relevant Primer for the Radiologist

After the nasal bones, the mandible is the second most common site of facial fractures, and mandibular fractures frequently require open reduction. In the trauma injury setting, multidetector computed tomography (CT) has become the cornerstone imaging modality for determining the most appropriate treatment management, fixation method, and surgical approach. Multidetector CT is also used to assess the adequacy of the reduction and evaluate potential complications in the postoperative period. For successful restoration of the mandible's form and function, as well as management of posttraumatic and postoperative complications, reconstructive surgeons are required to have a detailed understanding of mandibular biomechanics, occlusion, and anatomy. To provide added value in the diagnosis, treatment planning, and follow-up of mandibular fractures, radiologists should be aware of these concepts. Knowledge of the techniques commonly used to achieve occlusal and anatomic reduction and of the rationale behind the range of available treatment options for different injury patterns-from isolated and nondisplaced fractures to multisite and comminuted fractures-also is essential. This article focuses on the use of multidetector CT for pre- and postoperative evaluation of mandibular fractures and outlines fundamental concepts of diagnosis and management-beginning with an explanation of common fracture patterns and their biomechanical underpinnings, and followed by a review of the common postoperative appearances of these fractures after semirigid and rigid fixation procedures. Specific considerations regarding fractures in different regions of the tooth-bearing and non-tooth-bearing mandible and the unique issues pertaining to the edentulous atrophic mandible are reviewed, and key features that distinguish major from minor complications are described. (©)RSNA, 2016.

Mandible Fractures

Mandible fractures account for a significant portion of maxillofacial injuries and the evaluation, diagnosis, and management of these fractures remain challenging despite improved imaging technology and fixation techniques. Understanding appropriate surgical management can prevent complications such as malocclusion, pain, and revision procedures. Depending on the type and location of the fractures, various open and closed surgical reduction techniques can be utilized. In this article, the authors review the diagnostic evaluation, treatment options, and common complications of mandible fractures. Special considerations are described for pediatric and atrophic mandibles.

A chilling reminder: Pediatric facial trauma from recreational winter activities

BACKGROUND

Winter activities offer children and adolescents an outdoor recreational opportunity during the coldest months. Our objectives were to estimate the national incidence of facial injury associated with recreational winter activities. Furthermore, we analyze demographic trends and clinical characteristics of patients presenting to emergency departments (EDs).

METHODS

The National Electronic Injury Surveillance System (NEISS), a population-based resource, was evaluated for ED visits from 2010 to 2014 for children injured from "active" winter -undertakings (snowboarding, skiing, ice skating) and sledding/tubing. Entry narratives were evaluated for demographics, diagnoses, and other clinical factors.

RESULTS

841 entries amounting to an estimated 27,618 patients were evaluated. The most common injuries were lacerations (69.4%), contusions/abrasions (19.5%), and fractures (5.5%), with the most common fracture sites being the nose (60.9%), orbit (15.2%), and mandible (10.9%). Median age was 9 years (IQR 5-12), and 65.8% were male. A greater proportion of adolescents sustained fractures than younger children (8.1% vs. 4.0%). The majority of fractures were to the nose.

CONCLUSION

With nearly 30,000 ED visits over five years, participation in winter sports can be perilous. Adolescents harbor a greater risk of sustaining serious injuries than younger children, and patients injured sledding/tubing had a greater fracture risk compared to those participating in more "active" winter activities. As upper/mid-face fractures occurred in only 1.4%, these findings reinforce a very limited role for CT. These findings suggest a need for greater use of facial protection and closer supervision of older children participating in these activities.

Forgetful but not forgotten: Bathroom-related craniofacial trauma among the elderly

OBJECTIVES/HYPOTHESIS

As our population ages, injuries attributable to falls continue to increase, impacting healthcare delivery. Evaluation of craniofacial trauma with focus on elderly patients remains an underappreciated concern. Our objectives were to evaluate injury trends associated with elderly bathroom falls, as this information may be useful for counseling and preventive purposes.

STUDY DESIGN

Database review.

METHODS

The National Electronic Injury Surveillance System was evaluated for craniofacial trauma among patients 60 years and older presenting to the emergency department (ED) (2010-2014). Injury descriptions were reviewed for mechanism of injury, patient demographics, and other injury characteristics.

RESULTS

In total, 7.2% of the estimated 3.4 million ED visits for elderly craniofacial trauma were bathroom related. Females comprised the majority (60.9%) of patients, and a plurality of patients were in their 80s. A greater proportion of facial injuries resulted from syncope (16.6% vs. 10.9% compared to head injuries). Toilets facilitated a greater proportion of facial insults and were more likely to require admission; the most common mechanism was "falling off." Showers contributed a majority of head injuries and had a lower median age than toilet injuries. Fractures comprised 12.6% of facial injuries; of craniofacial fractures, common sites included the nose (54%), mandible (6%), and orbit (6%). Admitted patients were significantly older than those who were released.

CONCLUSIONS

Bathroom falls result in a significant proportion of elderly traumatic injury. The trends we present offer the opportunity for targeted preventative measures to decrease the occurrence of these events. Additionally, this information may adjunct a detailed history and physical to ensure appropriate patient management.

LEVEL OF EVIDENCE

4 Laryngoscope, 127:820-827, 2017.

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.

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

This tutorial outlines the details of the AOCMF image-based classification system for fractures of the mandibular arch (i.e. the non-condylar mandible) at the precision level 3. It is the logical expansion of the fracture allocation to topographic mandibular sites outlined in level 2, and is based on three-dimensional (3D) imaging techniques/computed tomography (CT)/cone beam CT). Level 3 allows an anatomical description of the individual conditions of the mandibular arch such as the preinjury dental state and the degree of alveolar atrophy. Trauma sequelae are then addressed: (1) tooth injuries and periodontal trauma, (2) fracture involvement of the alveolar process, (3) the degree of fracture fragmentation in three categories (none, minor, and major), and (4) the presence of bone loss. The grading of fragmentation needs a 3D evaluation of the fracture area, allowing visualization of the outer and inner mandibular cortices. To document these fracture features beyond topography the alphanumeric codes are supplied with distinctive appendices. This level 3 tutorial is accompanied by a brief survey of the peculiarities of the edentulous atrophic mandible. Illustrations and a few case examples serve as instruction and reference to improve the understanding and application of the presented features.

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.

Diagnostic efficacy of cone-beam computed tomography for mandibular fractures

OBJECTIVE

The aim of the study was to determine the clinical efficacy of maxillofacial cone-beam computed tomography (CBCT) for the diagnosis of suspected mandibular fractures and to evaluate whether findings would lead to a change in treatment.

STUDY DESIGN

CBCT imaging was performed for 164 patients with suspected mandibular fractures (231 sites) but equivocal clinical and radiological findings (conventional radiography). Images were interpreted by oral and maxillofacial surgeons and treatment decisions based on pre and postimaging were compared. Linear regression analyses were performed.

RESULTS

For 63.2% of sites (n = 146) the suspected diagnosis was confirmed by CBCT (P < .0001; R(2) = 0.93). For 4.33% of sites (n = 10) no fracture was identified. Additional fractures were identified in 17.75% (n = 41) and additional infractures in 14.72% (n = 34). The treatment plan was altered for 9.52% of sites (n = 22).

CONCLUSIONS

CBCT imaging of suspected mandibular fractures resulted in a change in the treatment plan in 9.52%.

Mandibular fracture patterns consistent with posterior maxillary fractures involving the posterior maxillary sinus, pterygoid plate or both: CT characteristics

OBJECTIVES

The aim of this study was to determine the incidence of posterior maxillary fractures involving the posterior maxillary sinus wall, pterygoid plate or both, unrelated to major midface fractures in patients with mandibular fractures, and to characterize associated fractures.

METHODS

A CT study was performed in patients with mandibular fractures to identify posterior maxillary fractures. Patients aged under 16 years, those with mandibular fractures involving only dentoalveolar components and those with concurrent major midfacial fractures were excluded.

RESULTS

13 (6.7%) of 194 patients with mandibular fractures also had posterior maxillary fractures (case group). The injury pattern correlated with the external force directed to the lateral side of the mandible (p < 0.001), alcohol consumption (p = 0.049), the presence of multifocal fractures (p = 0.002) and the fracture regions in the symphysis/parasymphysis (p = 0.001) and the angle/ramus (p = 0.001). No significant difference between the case and non-case groups was seen for age, sex or cause of trauma. Non-displaced fractures in the ipsilateral posterior mandible occurred with significant frequency (p = 0.001) when the posterior maxillary fractures involved only the sinus.

CONCLUSIONS

Mandibular fractures accompanied by posterior maxillary fractures are not rare. The finding of a unilateral posterior maxillary fracture on CT may aid the efficient radiological examination of the mandible based on possible patterns of associated fractures, as follows: in the ipsilateral posterior region as a direct fracture when the impact is a medially directed force, and in the symphysis/parasymphysis or contralateral condylar neck as an indirect fracture.

Late reconstruction of condylar neck and head fractures

Condyle fractures are a common injury, but only a few of these injuries require immediate or late reconstruction. The complications that most frequently necessitate condylar reconstruction include proximal segment degeneration, malunion, and ankylosis. Costochondral grafts and total joint prostheses, both stock and custom, remain the most common methods of reconstruction. Reconstruction plates with condylar extensions should only be used temporarily as an unacceptable number cause serious complications. Distraction osteogenesis may have an occasional role in reconstructing the posttraumatic condyle.

Imaging evaluation of facial complex strut fractures

High-resolution multidetector computed tomography with multiplanar reformations and 3-D postprocessing often provides the detail necessary for preoperative assessment of facial injuries. Maxillofacial fractures are classified in the following manner: upper face fractures, midface fractures (the most frequent), Le Fort fractures, and lower face or mandible fractures. The facial skeleton is a framework of vertical and horizontal buttresses that ensures a better resistance to trauma, but serves also as reference for maxillofacial surgery to restore facial size and shape. Radiologists should know how to diagnose and report the main types of facial fracture.

Diagnostic performance of dental students in identifying mandibular condyle fractures by panoramic radiography and the usefulness of reference images

Purpose

The purpose of this study was to evaluate the diagnostic performance of dental students in detection of mandibular condyle fractures and the effectiveness of reference panoramic images.

Materials and Methods

Forty-six undergraduates evaluated 25 panoramic radiographs for condylar fractures and the data were analyzed through receiver operating characteristic (ROC) analysis. After a month, they were divided into two homogeneous groups based on the first results and re-evaluated the images with (group A) or without (group B) reference images. Eight reference images included indications showing either typical condylar fractures or anatomic structures which could be confused with fractures. Paired t-test was used for statistical analysis of the difference between the first and the second evaluations for each group, and student's t-test was used between the two groups in the second evaluation. The intra- and inter-observer agreements were evaluated with Kappa statistics.

Results

Intra- and inter-observer agreements were substantial (k=0.66) and moderate (k=0.53), respectively. The area under the ROC curve (Az) in the first evaluation was 0.802. In the second evaluation, it was increased to 0.823 for group A and 0.814 for group B. The difference between the first and second evaluations for group A was statistically significant (p<0.05), however there was no statistically significant difference between the two groups in the second evaluation.

Conclusion

Providing reference images to less experienced clinicians would be a good way to improve the diagnostic ability in detecting condylar fracture.

Traumatic displacement of maxillary permanent incisor into the nasal cavity

PURPOSE

The purpose of this paper was to describe a case of unviable alveolar repositioning of an intruded tooth into the nasal cavity and to bring the subject of intrusive tooth injury among patients with dentoalveolar fractures to the attention of trauma surgeons.

PATIENT

A 26-year-old male was involved in a car accident and crashed his mouth against the dashboard due to sudden deceleration. Intraoral examination revealed an anterior maxillary dentoalveolar fracture and absence of the central maxillary incisors, right lateral maxillary incisor, and left maxillary canine. Computed tomography showed a dislocated tooth in the nasal cavity. The "missing" left maxillary canine was easily recovered from the floor of the left nostril.

CONCLUSIONS

Because complete dislocation of a tooth can cause a frontal sinus abscess, an airway complication, a respiratory tract obstruction, and a complicated lung abscess or sinusitis, anytime a tooth is not accounted for after a dentoalveolar trauma, the possibility that it has been fully intruded should be considered. Computed tomographic scan should be a routine diagnostic study in all cases with associated missing anatomical structures in the oral and maxillofacial region. The need to involve the dental professional in the initial assessment of dental trauma in emergency rooms in hospitals is important in order to identify how many teeth might be missing after dental trauma and to correctly reposition the avulsed teeth when possible.

Considerations of mandibular angle fractures during and after surgery for removal of third molars: a review of the literature

BACKGROUND

Angle fractures are quite common considering that the angle of the mandible forms an area of lower resistance which contains a thicker upper border, a thin basilar bone, and the presence of an impacted mandibular third molar. Common complications of mandibular third molar surgery include alveolar osteitis (dry socket), secondary infection, nerve dysfunction, and hemorrhage. Reports of mandibular fracture during and after third molar removal are uncommon.

PURPOSE

The purpose of this paper is to discuss the risk and predisposing factors that should be analyzed regarding the possibility of immediate and late mandibular angle fractures and their need for surgical treatment as a means through which to remove impacted molars. This study is based on a thorough review of the literature as well as on one immediate and one late mandibular angle fracture as described by the authors' own personal experience.

CONCLUSIONS

The danger of an immediate jaw fracture can be avoided by means of proper instrumentation and by refraining from excessive force on the bone. The tooth should be sectioned in such a way as to minimize the extent of bone removal and force caused by instrumentation. The danger of a late jaw fracture can be avoided by precise diagnosis in cases of patients over 25 years of age, particularly men, whose tooth roots are superimposed on or adjacent to the inferior alveolar canal on a panoramic image, any local pathology and systemic disease or medications which may impair bone strength, and patients who present bruxism and are active athletes.

Applications of cone-beam computed tomography in fractures of the maxillofacial complex

Imaging plays an essential role in the evaluation of maxillofacial fractures both pre- and postoperatively. Several studies support the use of conventional two-dimensional imaging for traumas involving mainly the mandible, but for more complex situations advanced imaging modalities such as computed tomography (CT) and magnetic resonance imaging have higher indication. Nowadays, besides CT, cone-beam computed tomography (CBCT) has appeared as a reasonable and reliable alternative considering radiation dosage, image quality and comfort for the patient. The purpose of this study was to review the fracture patterns involving the maxillofacial complex, provide a technical and practical comparison between CT and CBCT, and finally present the potential applications of CBCT illustrated with clinical examples.

Incidence and characterization of unifocal mandible fractures on CT

BACKGROUND AND PURPOSE

Conventional thinking among radiologists is that the mandible acts as a closed "ring" that needs to fracture at 2 points, though the frequency of multiple mandible fractures has been reported to be only as high as 67%. However, many of these studies did not use CT to confirm the presence of suggested fractures and excluded nondisplaced fractures. The purpose of this study was to determine the incidence of unifocal mandibular fractures on the basis of detection with dedicated facial bone CT scans and to characterize these fractures.

MATERIALS AND METHODS

We retrospectively reviewed the imaging reports of patients during a 3-year period to identify those who had mandible fractures documented on dedicated facial bone CT scans. The incidence of unifocal fractures was determined, the unifocal fractures were further subcategorized, and any derangements of the temporomandibular joints were also evaluated.

RESULTS

One hundred two patients met the inclusion criteria. The incidence of unifocal mandible fractures was 42% (43/102). Three unifocal fracture patterns identified were the following: simple fractures (25/42, 58%), comminuted fractures (11/42, 26%), and fractures associated with condylar subluxations (7/42, 16%). Most fractures had none to mild displacement or distraction.

CONCLUSION

Unifocal mandible fractures occur with greater frequency than anticipated by most radiologists. This may be due to the somewhat dynamic nature of the mandibular "ring," which includes the temporomandibular joints, though joint derangements evident on CT occur in the minority of cases.

Posttraumatic Mandibular Deformities

In covering the Emergency Department, the Plastic Surgeon can be faced with the mandibular fracture patient. Although the timely repair of the fracture usually leads to normal function and appearance, occasionally the surgeon is faced with the untoward sequelae of the mandible fracture. Post-traumatic mandibular deformities include non-union, malunion, malocclusion, TMJ dysfuction, and facial asymmetry. The difficulty in treatment of these deformities can be compounded by edentulous mandibles, substance abuse, and approach controversies such as the timing of the repair and surgical versus non-surgical management. Knowledge of the post-traumatic mandibular deformities by the treating physician not only assists in their management but may also allow for their prevention.