Imaging of high-energy midfacial trauma: what the surgeon needs to know

Does Integration of Technology and Customization of Implants Produce Better Outcomes in Post-Traumatic Orbital Reconstruction? A Systematic Review and Meta-Analysis

PURPOSE

This review aims to compare and evaluate the outcomes achieved by integrating technological aids and the influence of different implant designs in the reconstruction of post-traumatic orbital defects.

METHODS

Electronic searches of the MEDLINE, Embase, Cochrane Library, and Google Scholar databases until March 2023 were conducted. Clinical controlled trials, observational studies, cohort studies, and retrospective studies were identified and included. The predictor variables were the integration of technological aids namely, computer-assisted surgical planning, mirror image overlay, and intraoperative navigation with the utilization of different orbital implant designs (standard orbital meshes, preformed implants, prebent implants, and patient-specific implant [PSI]) during post-traumatic orbital reconstruction. The primary outcome variables were orbital volume, diplopia, and enophthalmos. Weighted or mean difference and risk ratios at 95% confidence intervals were calculated, where P ＜ .05 was considered significant and a random effects model was adopted.

RESULTS

This review included 7 studies with 560 participants. The results indicate that the difference in postoperative orbital volume between affected and nonaffected eye showed no statistically significant difference between PSI and prebent group (mean difference, -0.41 P = .28, I2 = 46%). PSI group resulted in diplopia 0.71-fold less than that of the standard orbital mesh group but was not statistically significant (P = .15). Standard orbital mesh group is 0.30 times at higher risk of developing enophthalmos as compared to PSI group (P = .010). The literature suggests PSIs are preferred for patients with large defects (Jaquiéry's III-IV), whereas prebent implants are equally effective as PSIs in patients with preserved infraorbital buttress and retrobulbar bulge.

CONCLUSION

PSIs are associated with improved outcomes, especially for correcting enophthalmos. The data suggests the potential efficacy of prebent implants and PSIs in orbital volume corrections. There is a lack of randomized studies. This review should serve as a recommendation for further studies to contribute to the existing literature.

Orthodontic maxillary molar movement-induced zygomatic pillar remodeling and its consequences on occlusal characteristics and stress distribution

OBJECTIVE

We aimed to evaluate changes in the zygomatic pillar during orthodontic treatment involving premolar extraction, analyze the effects of maxillary first molar movement on zygomatic pillar remodeling, and examine occlusal characteristics and stress distribution after remodeling.

METHODS

Twenty-five patients who underwent premolar extraction were included in the study. The zygomatic pillar measurement range was defined, and cross-sectional areas, surface landmark coordinates, alveolar and cortical bone thicknesses, and density changes were assessed using Mimics software based on the cone-beam computed tomography scans taken before (T0) and after the treatment (T1). Multiple linear regression analysis was performed to determine the correlation between changes in the zygomatic pillar and maxillary first molar three-dimensional (3D) movement and rotation. Additionally, the correlation between pillar remodeling and occlusal characteristics was analyzed by Teetester. Pre- and post-reconstruction 3D finite element models were constructed and loaded with an average occlusal force of two periods.

RESULTS

The morphological and structural remodeling of the zygomatic pillar after orthodontic treatment involving premolar extraction showed a decreased cross-sectional area of the lower segment of the zygomatic pillar. The zygomatic process point moved inward and backward, whereas the zygomatico-maxillary suture point moved backward. The thicknesses of the zygomatic pillar alveolar and cortical bones were thinner, and reduced alveolar bone density was observed. Simultaneously, the movement and angle change of the maxillary first molar could predict zygomatic pillar reconstruction to a certain extent. With decreasing the total occlusal force and the occlusal force of the first molar, occlusal force distribution was more uniform. With zygomatic pillar remodeling, occlusal stress distribution in the zygomatic alveolar ridge decreased, and occlusal stress was concentrated at the junction of the vertical and horizontal parts of the zygomatic bone and the posterior part of the zygomatic arch.

CONCLUSIONS

Orthodontic treatment involving premolar extraction led to zygomatic pillar remodeling, making it more fragile than before and reducing the occlusal force of the maxillary first molar and the entire dentition with stress concentrated in weak areas.

CLINICAL RELEVANCE

No other study has focused on the effects of orthodontics on pillar structures. The present study indicates that the mesial movement of the maxillary first molar weakened the zygomatic pillar and reduced occlusal function, thereby providing insights for inserting anchorage screws and facial esthetics.

A new approach to recording nasal fracture in skeletonized individuals

OBJECTIVE

This work describes a new method for recording nasal fracture in skeletonized individuals, suitable for use in biocultural studies of violence and fracture in past societies.

METHODS

The method consists in recording the 'side of fracture', 'side of deviation', 'type of fracture', 'other facial fractures', and stage of 'bone remodeling'.

RESULTS

A lateral impact force to the facial area is typical of interpersonal violence. This may result in a unilateral nasal fracture and/or a laterally deviated nose. Given the predominance of right-handedness in human populations, side of fracture and, especially, side of deviation, may be useful indices of interpersonal violence. As regards fracture type, although a distal fracture of the nasal bones is the most common type, their comminution may be associated with higher impact forces. The presence of other facial fractures may also be an indicator of high-energy impacts.

CONCLUSIONS

Different patterns of nasal trauma may be consistent with different etiologies.

SIGNIFICANCE

The method is focused at improving our ability to distinguish the direction and type of impact that caused the injury and, in particular, whether, at a population or sub-group level, such injuries are likely to be predominantly due to violence or to other causes.

LIMITATIONS

Well healed fractures of the nasal bones or injury to the septum may be difficult to identify. Also, it is not possible to confirm if nasal and other facial fractures are temporally concurrent.

SUGGESTIONS FOR FURTHER RESEARCH

To test this method using skeletal collections with known trauma history or 3D prints of modern nasal injuries of known etiologies.

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.

Dynamic changes of facial skeletal fractures with time

To investigate the characteristics of imaging changes with time of facial fractures, patients with facial fractures who had computed tomographic scan were enrolled including 500 patients who were divided into six groups based on the time of scanning: super early (<3 d), early (4–7 d), early-to-medium (8–14 d), medium (15–21d), medium-to-late (22d–2 months) and late stage (>2 months). The data were compared and analyzed. Forty two patients with frontal bone fractures had high-energy impact as the reason of fractures. The fracture line was clear and sharp within one week but blunt and sclerotic due to bone absorption at 2–3 weeks, and might exist for a long time. All patients had soft tissue swelling and paranasal sinus effusion at 1–2 weeks after injury. Air might gather in the adjacent soft tissues and/or intracranially within 3 days of injury if the fracture involved the frontal or other sinuses. Twelve of the 42 patients (28.6%) had intracranial hematoma, and five (11.9%) had epidural effusion. Subarachnoid hemorrhage was mostly absorbed within one week while epidural hematoma was completely absorbed over 3 weeks. Significant changes (P < 0.05) in the fracture lines, effusion of paranasal sinuses, soft tissue swelling and pneumocephalus were observed during the study period. For patients with medial orbital wall fractures, the fracture line was sharp and clear at early stages with concurrent sphenoid sinus effusion, and the fracture line became depressed 3 weeks later with disappearance of sphenoid sinus effusion. Significant changes (P < 0.05) were observed in the sharp fracture line, soft tissue swelling, sphenoid sinus effusion and smooth depression at fracture sites. For nasal fractures, the fracture line was sharp and clear at early stages with concurrent soft tissue swelling which disappeared one week later. The fracture line became smooth three weeks later. A significant (P < 0.05) difference was demonstrated in the changes of fracture line and soft tissue swelling with time. In conclusion, facial fractures have some dynamic alterations with time and identification of these characteristics may help reaching a correct clinical diagnosis with regard to fracture severity and time.

Functional stability analyses of maxillofacial skeleton bearing cleft deformities

The symmetrically stable craniofacial bony structure supports the complex functions and delicate contour of the face. Congenital craniofacial deformities are often accompanied by bony defects and have been repetitively correlated with compromised dento-maxillary stability, but neither the extent nor the pattern of cleft-related maxillary instability has been explored in detail. Furthermore, it is largely unknown if the bony defect and related instability are correlated with secondary maxillary deformity common among patients with orofacial clefts. With the aid of finite element modeling, we studied the detailed relationship between cleft-related bony defect and maxillary stability under occlusal loading. Craniofacial models were generated based on cone-beam computed tomography data and loaded with mimicked bite forces along the axial axis of each tooth. Our data showed that all cleft models exhibited more asymmetrical deformations under mastication compared with the normal. Models with palatal cleft demonstrated greater asymmetry, greater dental arch contraction, and less maxillary protrusion compared to models with alveolar cleft only. For unilateral cleft models, alveolus on non-cleft side tended to be more protruded and lifted than the cleft side. For bilateral cleft models, the most prominent feature was the seriously contracted alveolar arch and curved and pitched premaxillae. These findings indicated cleft type-specific pattern of maxillary instability, which were largely in accordance with dentoalveolar morphological features among patients. Collectively, our study elucidated the detailed relationship between cleft bony defect and the pattern of maxillary instability, and suggested a prototype for studying the abnormal maxillary and dental arch growth among patients with craniofacial deformities.

Diagnostic performance of brain computed tomography to detect facial bone fractures

Objective

Most patients with head trauma require brain computed tomography (CT) in the emergency department. However, the requirement for facial CT remains controversial. The aim of this study was to evaluate the diagnostic value of brain CT alone for detection of facial fractures and its ability to determine the requirement for additional facial CT.

Methods

This retrospective multicenter study was conducted in two tertiary hospitals in Seoul, Republic of Korea, between January 2014 and December 2015. Data were collected from the medical records of adult patients (aged over 18 years) who had undergone both brain and facial CT on the same day as their presentation to the emergency department with blunt trauma to the head and face. The same radiologist analyzed all brain and facial CT images.

Results

Eight hundred and sixty patients (668 men, 192 women; mean age 48.60±18.2 years) were identified to have had facial fractures. There was a statistically significant predominance of men but not of any particular age group. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of brain CT were 83.72%, 98.87%, 97.17%, 92.92%, and 94.08%, respectively.

Conclusion

These findings suggest that brain CT has high diagnostic value for detection of upper facial bone fractures with high accuracy and can aid emergency physicians when determining the requirement for additional facial CT.

Review of In Vivo Bone Strain Studies and Finite Element Models of the Zygomatic Complex in Humans and Nonhuman Primates: Implications for Clinical Research and Practice

The craniofacial skeleton is often described in the clinical literature as being comprised of vertical bony pillars, which transmit forces from the toothrow to the neurocranium as axial compressive stresses, reinforced transversely by buttresses. Here, we review the literature on bony microarchitecture, in vivo bone strain, and finite-element modeling of the facial skeleton of humans and nonhuman primates to address questions regarding the structural and functional existence of facial pillars and buttresses. Available bone material properties data do not support the existence of pillars and buttresses in humans or Sapajus apella. Deformation regimes in the zygomatic complex emphasize bending and shear, therefore conceptualizing the zygomatic complex of humans or nonhuman primates as a pillar obscures its patterns of stress, strain, and deformation. Human fossil relatives and chimpanzees exhibit strain regimes corroborating the existence of a canine-frontal pillar, but the notion of a zygomatic pillar has no support. The emerging consensus on patterns of strain and deformation in finite element models (FEMs) of the human facial skeleton corroborates hypotheses in the clinical literature regarding zygomatic complex function, and provide new insights into patterns of failure of titanium and resorbable plates in experimental studies. It is suggested that the "pillar and buttress" model of human craniofacial skeleton function be replaced with FEMs that more accurately and precisely represent in vivo function, and which can serve as the basis for future research into implants used in restoration of occlusal function and fracture repair. Anat Rec, 299:1753-1778, 2016. © 2016 Wiley Periodicals, Inc.

Core curriculum illustration: orbital blow out fracture

This is the 32nd installment of a series that will highlight one case per publication issue from the bank of cases available online as part of the American Society of Emergency Radiology (ASER) educational resources. Our goal is to generate more interest in and use of our online materials. To view more cases online, please visit the ASER Core Curriculum and Recommendations for Study online at: http://www.erad.org/page/CCIP_TOC.

Do Radiologists and Surgeons Speak the Same Language? A Retrospective Review of Facial Trauma

OBJECTIVE

The objective of the present study is to examine the concordance of facial fracture classifications in patients with trauma who underwent surgery and to assess the epidemiologic findings associated with facial trauma.

MATERIALS AND METHODS

Patients with trauma who underwent facial CT examination and inpatient operative intervention during a 1-year period were retrospectively analyzed. Patient demographic characteristics, the mechanism of injury, the radiology report, the surgical diagnosis, and clinical indications were reviewed. Fractures were documented according to bone type and were classified into the following subtypes: LeFort 1, LeFort 2, LeFort 3, naso-orbital-ethmoidal, zygomaticomaxillary complex (ZMC), orbital, and mandibular. Concordance between the radiology and surgery reports was assessed.

RESULTS

A total of 115,000 visits to the emergency department resulted in 9000 trauma activations and 3326 facial CT examinations. One hundred fifty-six patients (4.7%) underwent facial surgical intervention, and 133 cases met criteria for inclusion in the study. The mean injury severity score was 10.2 (range, 1-75). The three most frequently noted injury mechanisms were as follows: assault (77 cases [57.9%]), a traffic accident (21 cases [15.8%]), and a fall (20 cases [15%]). The three most frequently noted facial bone fractures were as follows: mandible (100 cases [75.2%]), maxilla (53 cases [39.8%]), and orbit (53 cases [39.8%]). The five descriptors most frequently found in the radiology and surgery reports were the mandibular angle (25 cases), the orbital floor (25 cases), the mandibular parasymphysis (22 cases), the mandibular body (21 cases), and ZMC fractures (19 cases). A classification was not specified in 31 of the radiologic impressions (22.5%), with 28 of 31 radiologists expecting the surgeon to read the full report. The descriptors used in the radiology and surgery reports matched in 73 cases (54.9%) and differed in 51 cases (38.3%). No classifications were used by one or both specialties in nine cases (6.8%).

CONCLUSION

For 38.3% of patients needing facial surgery, descriptors used in the radiologic and surgery reports differed. Speaking a common language can potentially improve communication between the radiology and surgery services and can help expedite management of cases requiring surgery.

A prospective analysis of physical examination findings in the diagnosis of facial fractures: Determining predictive value

BACKGROUND

There are >150,000 patient visits per year to emergency rooms for facial trauma. The reliability of a computed tomography (CT) scan has made it the primary modality for diagnosing facial skeletal injury, with the physical examination playing more a cursory role. Knowing the predictive value of physical findings in facial skeletal injuries may enable more appropriate use of imaging and health care resources.

OBJECTIVE

A blinded prospective study was undertaken to assess the predictive value of physical examination findings in detecting maxillofacial fracture in trauma patients, and in determining whether a patient will require surgical intervention.

METHODS

Over a four-month period, the authors' team examined patients admitted with facial trauma to the emergency department of their hospital. The evaluating physician completed a standardized physical examination evaluation form indicating the physical findings. Corresponding CT scans and surgical records were then reviewed, and the results recorded by a plastic surgeon who was blinded to the results of the physical examination.

RESULTS

A total of 57 patients met the inclusion criteria; there were 44 male and 13 female patients. The sensitivity, specificity, positive predictive value and negative predictive value of grouped physical examination findings were determined in major areas. In further analysis, specific examination findings with n≥9 (15%) were also reported.

CONCLUSIONS

The data demonstrated a high negative predictive value of at least 90% for orbital floor, zygomatic, mandibular and nasal bone fractures compared with CT scan. Furthermore, none of the patients who did not have a physical examination finding for a particular facial fracture required surgery for that fracture. Thus, the instrument performed well at ruling out fractures in these areas when there were none. Ultimately, these results may help reduce unnecessary radiation and costly imaging in patients with facial trauma without facial fractures.

A prospective analysis of physical examination findings in the diagnosis of facial fractures: Determining predictive value

Background

There are >150,000 patient visits per year to emergency rooms for facial trauma. The reliability of a computed tomography (CT) scan has made it the primary modality for diagnosing facial skeletal injury, with the physical examination playing more a cursory role. Knowing the predictive value of physical findings in facial skeletal injuries may enable more appropriate use of imaging and health care resources.

Objective

A blinded prospective study was undertaken to assess the predictive value of physical examination findings in detecting maxillofacial fracture in trauma patients, and in determining whether a patient will require surgical intervention.

Methods

Over a four-month period, the authors' team examined patients admitted with facial trauma to the emergency department of their hospital. The evaluating physician completed a standardized physical examination evaluation form indicating the physical findings. Corresponding CT scans and surgical records were then reviewed, and the results recorded by a plastic surgeon who was blinded to the results of the physical examination.

Results

A total of 57 patients met the inclusion criteria; there were 44 male and 13 female patients. The sensitivity, specificity, positive predictive value and negative predictive value of grouped physical examination findings were determined in major areas. In further analysis, specific examination findings with n≥9 (15%) were also reported.

Conclusions

The data demonstrated a high negative predictive value of at least 90% for orbital floor, zygomatic, mandibular and nasal bone fractures compared with CT scan. Furthermore, none of the patients who did not have a physical examination finding for a particular facial fracture required surgery for that fracture. Thus, the instrument performed well at ruling out fractures in these areas when there were none. Ultimately, these results may help reduce unnecessary radiation and costly imaging in patients with facial trauma without facial fractures.

Postprocessing in Maxillofacial Multidetector Computed Tomography

Multidetector computed tomography (CT) and volumetric rendering techniques have always been a useful support for the anatomical and pathological study of the maxillofacial district. Nowadays accessibility to multidetector CT scanners allows the achievement of images with an extremely thin collimation and with high spatial resolution, not only along the axial plane but also along the patient's longitudinal axis. This feature is the main theoretical assumption for multiplanar imaging and for an optimal 3-dimensional postprocessing. Multiplanar reconstruction (MPR) techniques permit images along any plane in the space to be obtained, including curved planes; this feature allows the representation in a single bidimensional image of different anatomical structures that develop on multiple planes. For this reason MPR techniques represent an unavoidable step for the study of traumatic pathology as well as of malformative, neoplastic, and inflammatory pathologies. Among 3-dimensional techniques, Maximum Intensity Projection and Shaded Surface Display are routinely used in clinical practice. In addition, volumetric rendering techniques allow a better efficacy in representing the different tissues of maxillofacial district. Each of these techniques give the radiologist an undoubted support for the diagnosis and the characterization of traumatic and malformative conditions, have a critical utility in the neoplastic evaluation of primary or secondary bone involvement, and are also used in the planning of the most modern radiosurgical treatments. The aim of this article is to define the main technical aspects of imaging postprocessing in maxillofacial CT and to summarize when each technique is indicated, according to the different pathologies of this complex anatomical district.

Emergency radiology: Maxillofacial and skull-base trauma

Craniofacial trauma is common following road-traffic accidents, assaults and falls and may occur in isolation or associated with other body injuries. Due to the complexity of the maxillofacial and skull-base region, initial diagnosis may be inaccurate or delayed, leading to significant morbidity. Multidetector computed tomography is the modality of choice following high-energy blunt or penetrating trauma. It allows accurate evaluation of the fracture patterns and associated soft tissue complications and aids the appropriate medical and surgical treatment. In this article, we review and classify the most common traumatic injuries to the maxillofacial and skull-base region and outline the role of imaging in establishing complications and prognosis.

Acute facial trauma in falling accidents: MDCT analysis of 500 patients

The aim of this study is to assess multidetector computed tomography (MDCT) findings of facial trauma due to a falling accident. Using picture-archiving and communications system, we retrieved all MDCT requests for suspected facial injury during a 62-month period. Images were interpreted by two researchers. Five hundred patients met the inclusion criteria and 329 (66%) had a total of 515 fractures. Falls on stairs were seen in 109 (22%) patients and slips or trips in 391 (78%). The corresponding number of fractures was 169 (33%) and 346 (67%). Males (N = 241) had more fractures than females (N = 259), 327 vs. 188, respectively. The zygomatic complex was the most common fracture, seen in 40% of patients suffering a fracture. Twenty patients (4%) had fractures involving the sinus walls without paranasal sinus effusions. Facial fractures due to falls are common. The zygomatic complex is the most common fracture. A clear sinus sign may be less reliable than previously thought.

Facial fractures: beyond Le Fort

This article presents a systematic approach for interpreting a craniofacial CT scan that is clinically useful to the reconstructive surgeon. By categorizing the fracture patterns and highlighting the variables that may affect fracture management, the radiologist can expand his interpretation of the fracture pattern into a clinically useful diagnosis that may affect fracture management.

Computed tomography imaging findings of simultaneous bifid mandibular condyle and temporomandibular joint ankylosis: case report

Bifid mandibular condyle is an uncommon entity described in the literature as having a controversial etiology. Despite the absence of clinical symptomatology, the radiologist must be aware and should have some knowledge of this abnormality, as well its implications regarding functional and morphological changes. TMJ ankylosis is a disabling disease with involvement of the mandibular condyle, articular fossa and base of the skull. The association of bifid condyle with temporomandibular joint ankylosis is rare and must be carefully evaluated. The purpose of this paper is to report a case of simultaneous bifid mandibular condyle and temporomandibular joint ankylosis and to describe its computed tomography imaging findings.

Facial soft tissue injuries as an aid to ordering a combination head and facial computed tomography in trauma patients

PURPOSE

While the trauma computed tomography (CT) head scan is frequently ordered during resuscitation of multiply injured patients, determining when also to order facial CT in these situations can be difficult. Consequently, facial fractures are commonly missed on initial imaging evaluation. In acute trauma situations, facial soft tissue injury markers are often used to aid in this decision. A study was undertaken to identify exactly which facial soft tissue injuries correlate with facial fractures and which did not. The aim of our research was to compare the facial soft tissue injury patterns of patients receiving a combination head and facial CT who had facial fractures versus those who had no facial fractures.

PATIENTS AND METHODS

A retrospective trauma registry review was performed for a 5-year period at Legacy Emanuel Hospital, a level 1 trauma center. The trauma team saw a total of 9,871 trauma patients and 49.9% required head CT as part of their initial evaluation. A total of 777 (15.7%) patients had a combination head and facial CT in which 477 (61.4%) had a facial fracture and 300 (38.6%) had no facial fracture. Statistical significance was established using Bonferroni corrected P values less than .05.

RESULTS

Lacerations occurring in areas of the lips, nose, and intraorally, as well as wounds leading to periorbital contusion and subconjunctival hemorrhage, were significantly prevalent in the fracture group. Conversely, scalp lacerations and scalp contusions were significantly higher in the nonfracture group. Other injuries such as lacerations of the tongue, chin, forehead, cheek, ear, eyelid, and eyebrow were indistinguishable between both groups.

CONCLUSIONS

Our data demonstrate that there are certain facial soft tissue injury zones that correlate with facial fractures in trauma patients who obtain head CT. We would like to propose that the acronym LIPS-N (Lip laceration, Intraoral laceration, Periorbital contusion, Subconjunctival hemorrhage, and Nasal laceration) be used in conjunction with a physical examination when assessing if a trauma patient who is getting head CT should also get facial CT.

Radiologic assessment of maxillofacial, mandibular, and skull base trauma

Cranio-maxillofacial injuries affect a significant proportion of trauma patients either in isolation or concurring with other serious injuries. Contrary to maxillofacial injuries that result from a direct impact, central skull base and lateral skull base (petrous bone) fractures usually are caused by a lateral or sagittal directed force to the skull and therefore are indirect fractures. The traditional strong role of conventional images in patients with isolated trauma to the viscerocranium is decreasing. Spiral multislice CT is progressively replacing the panoramic radiograph, Waters view, and axial films for maxillofacial trauma, and is increasingly being performed in addition to conventional films to detail and classify trauma to the mandible as well. Imaging thus contributes to accurately categorizing mandibular fractures based on location, into alveolar, mandibular proper, and condylar fractures-the last are subdivided into intracapsular and extracapsular fractures. In the midface, CT facilitates attribution of trauma to the categories central, lateral, or combined centrolateral fractures. The last frequently encompass orbital trauma as well. CT is the imaging technique of choice to display the multiplicity of fragments, the degree of dislocation and rotation, or skull base involvement. Transsphenoid skull base fractures are classified into transverse and oblique types; lateral base (temporal bone) trauma is subdivided into longitudinal and transverse fractures. Supplementary MR examinations are required when a cranial nerve palsy occurs in order to recognize neural compression. Early and late complications of trauma related to the orbit, anterior cranial fossa, or lateral skull base due to infection, brain concussion, or herniation require CT to visualize the osseous prerequisites of complications, and MR to define the adjacent brain and soft tissue involvement.

Orbital apex injury: trauma at the junction between the face and the cranium

Orbital apex injury is usually seen in multiply and severely injured patients who are subject to high-energy trauma. Orbital apex injury rarely occurs in isolation. By proximity, the face, the skull base, or their combination are the most likely regions to be injured in association with orbital apex trauma. The vast majority of these injuries occur as an extension of orbital, LeFort, naso-orbito-ethmoid, panfacial, sphenoid, or temporal bone fractures of the skull. Complex osseous anatomic structures with intimately related multiple neurovascular organs make injuries to the orbital apex diagnostically and therapeutically challenging. Often other facial fractures extend into the orbital apex, or the orbital apex is damaged in conjunction with fractures of the skull base. Therefore abnormal imaging findings within the orbital apex may be indicators of traumatic injury to the entire junctional zone of face and cranium. In this article, we will give an overview of normal CT anatomy, review clinical syndromes, which may indicate traumatic injury of the orbital apex and present an imaging strategy for evaluation of the orbital apex.