Head injuries in falls from a standing height: Do fractures of the orbital roof matter? A prospective autopsy study

Purpose

The aim of this study was to analyze the occurrence and characteristics of orbital roof fractures, periorbital hematoma, conjunctival hemorrhage, orbital roof discoloration, and concomitant head injuries in falls from a standing height.

Methods

A prospective autopsy study was performed over a 4-year period (from 2010 to 2013). Subjects who had died due to traumatic brain injury caused by falls from a standing height were included in the study.

Results

Fifty cases of ground level falls were recorded. This group consisted of 39 men and 11 women, with an average age of 67.3 ± 13.6 years, and median age of 70 years. Skull fractures originating in the proximity of impact site were found in 47 of 50 individuals, and 22 had isolated orbital roof fractures not connected to the fracture line. Bluish discoloration of the orbital roof was noted in 19 subjects, 14 had periorbital hematomas, and 12 had blotchy or purpura-like conjunctival hemorrhages.

Conclusions

Isolated orbital roof fractures in falls from a standing height are easily detected using a standard autopsy technique, with special regard to careful removal of the dura in the anterior cranial fossa. Our study shows that orbital roof fractures can occur in accidental falls from a standing height and may not be associated with concomitant skull fractures and brain injuries.     

鼻咽癌侵犯前中颅窝的MRI表现

目的探讨鼻咽癌向前、中颅窝侵犯的ＭＲＩ征象。方法回顾分析３９例有颅神经损伤并经病理确诊的鼻咽癌病例,用１．０Ｔ磁共振机,行头颅、鼻咽部轴位和冠状面Ｔ１ＷＩ、Ｔ２ＷＩ和矢状面Ｔ２ＷＩ扫描,应用钆喷替酸葡甲胺（ＧｄＤＴＰＡ）增强后,分别行轴位、冠状面、矢状面Ｔ１ＷＩ扫描。结果（１）前颅窝受侵１３例,筛窦受侵３例,眶尖、球后受侵４例,两者同时受侵６例。（２）中颅窝受侵３８例,蝶骨体破坏３２例,蝶窦肿块２５例,破裂孔异常２０例,卵圆孔异常２８例,蝶鞍破坏６例,海绵窦受侵３５例。结论鼻咽癌经破坏颅底骨质、进出颅腔的自然骨性通道和两者并存的３种途径向前、中颅窝侵犯,ＭＲＩ能准确显示侵犯途径和程度     

Ethmoid sinus disease: CT evaluation in 400 cases. Part III. Craniofacial resection

Of 400 patients with ethmoid sinus disease, 18 had undergone craniofacial resection. This operation is an aggressive surgical procedure directed at total en bloc extirpation of tumors that extend through the floor of the anterior cranial fossa. Recent advances in surgical technique have made it the procedure of choice for sinonasal tumors that extend through the cribriform plate, fovea ethmoidalis, and orbital roof. Specifically, this operation has had excellent results in patients with esthesioneuroblastomas. Radiologists must be aware of the possible pitfalls in interpreting the postoperative computed tomographic scans and the findings that suggest tumor recurrence.     

Orbit deformities in craniofacial neurofibromatosis type 1

BACKGROUND AND PURPOSE: The possible relationship of orbit deformities in neurofibromatosis type 1 (NF1) to plexiform neurofibromas (PNFs) have not been fully elucidated. Our purpose was to review orbital changes in patients with craniofacial NF1. METHODS: We retrospectively reviewed CT and MR imaging abnormalities of the orbit in 31 patients (18 male, 13 female; mean age, 14 years; age range 1-40 years) with craniofacial NF1. RESULTS: Orbital abnormalities were documented in 24 patients. Six had optic nerve gliomas with enlarged optic canals. Twenty had PNFs in the orbit or contiguous to the anterior skull. The posterior orbit was distorted by encroachment from an expanded middle cranial fossa in 13 patients, and 18 had enlargement of the orbital rim. Other changes included focal decalcification or remodeling of orbital walls adjacent to PNFs in 18 patients and enlargement of cranial foramina resulting from tumor infiltration of sensory nerves in 16. These orbital deformities were sometimes progressive and always associated with orbital infiltration by PNFs. CONCLUSION: In our patients with craniofacial neurofibromatosis, bony orbital deformity occurred frequently and always with an optic nerve glioma or orbital PNF. PNFs were associated with orbital-bone changes in four patterns: expansion of the middle cranial fossa into the posterior orbit, enlargement of the orbital rim, bone erosion and decalcification by contiguous tumor, and enlargement of the cranial foramina. Orbital changes support the concept of secondary dysplasia, in which interaction of PNFs with the developing skull is a major component of the multifaceted craniofacial changes possible with NF1.     

The CT characteristics of orbital blowout fracture and its medicolegal expertise

To explore the CT characteristics of orbital blowout fracture, we reviewed 76 cases with orbital blowout fracture and analyzed their clinical forensic characteristics. The missed diagnosis rate of cranial CT was 26.3%, and plain X-ray was 47.4%. The orbital CT examination has advantages in diagnosing orbital blowout fracture. In 42 cases fractures were simple medial orbital wall fracture, 30 cases were inferior orbital fractures. Loss of clinical signs included local haematoma, bone continuity, and displacement of bone fragments were mostly seen in CT image. Clinical signs and symptoms included local haematoma, whilst diplopia as the most common clinical symptom. Visual acuity was rarely affected after fracture. It is concluded that orbital blowout fracture may be misdiagnosed if only cranial CT and plain X-ray are used. Diagnose the orbital blowout fracture only by craniocerebral CT and head X-ray. Orbital CT should be done if the clinical signs are suggestive of orbital blowout fracture Visual acuity was affected and diplopia may be present.     

Inflammatory orbital pseudotumor with infratemporal fossa extension mimicking temporomandibular joint dysfunction

Inflammatory orbital pseudotumor is a benign space-occupying lesion of unknown origin that involves all or part of the fatty tissue within the orbit. Occasionally the disease may extend into the middle cranial, the pterygopalatine, and the infratemporal fossa through the various foramina of the orbit, although extension into the infratemporal fossa is very rare. We present a case which extends into the infratemporal fossa through the inferior orbital fissure, resulting in presenting symptoms mimicking temporomandibular joint dysfunction.     

A retrospective analysis of spontaneous sphenoid sinus fistula: MR and CT findings

BACKGROUND AND PURPOSE: The sphenoid sinus is rarely implicated as a site of spontaneous CSF fistula. We undertook this study to evaluate the potential etiopathogenesis of spontaneous CSF fistula involving the sphenoid sinus and to review the imaging findings. METHODS: We retrospectively reviewed the imaging findings of 145 cases of CSF fistula from our departmental archives (August 1995 through August 1998). Fifteen (10%) patients had CSF fistulas involving the sphenoid sinus. Eleven (7%) patients had spontaneous CSF fistulas, whereas in four patients, the CSF fistulas in the sphenoid sinus were related to trauma. Of the 11 patients, nine underwent only plain high-resolution CT and MR cisternography. One patient additionally underwent contrast-enhanced CT cisternography, and one other patient underwent MR cisternography only. For each patient, the CSF fistula site was surgically confirmed. The MR imaging technique included T1-weighted and fast spin-echo T2-weighted 3-mm-thick coronal sequences obtained with the patient in the supine position. The plain high-resolution CT study included 3-mm-thick, and sometimes 1- to 1.5-mm-thick, coronal sections obtained with the patient in the prone position. Similar sections were obtained after injecting nonionic contrast material intrathecally via lumbar puncture for the CT cisternographic study. We evaluated each of the 11 patients for the exact site of CSF leak in the sphenoid sinus. We also determined the presence of pneumatization of lateral recess of the sphenoid sinus, orientation of the lateral wall of the sphenoid sinus, presence of arachnoid pits, presence of brain tissue herniation, and presence of empty sella in each of these patients. RESULTS: The exact sites of the CSF fistulas were documented for all 11 patients by using plain high-resolution CT, MR cisternography, or CT cisternography. In nine (82%) patients, the sites of the CSF fistulas were at the junction of the anterior portion of the lateral wall of the sphenoid sinus and the floor of the middle cranial fossa. In the remaining two (18%) patients, the sites of the CSF fistulas were along the midportion of the lateral wall of the sphenoid sinus. Of these 11 patients, one had bilateral sites of the CSF fistula at the junction of the anterior portion of the lateral wall of the sphenoid sinus with the floor of the middle cranial fossa. In nine (82%) patients, the presence of brain tissue herniation was revealed, and this finding was best shown by MR cisternography. Ten (91%) patients had extensive pneumatization of the lateral recess of the sphenoid sinus, with an equal number having outward concave orientation of the inferior portion of the lateral wall of the sphenoid sinus. In seven (63%) patients, the presence of arachnoid pits, predominantly along the anteromedial aspect of the middle cranial fossa, was shown. In seven (63%) patients, empty sella was shown. For comparison, we reviewed the CT studies of the paranasal sinuses in 100 age-matched control subjects from a normal population. Twenty-three had extensive lateral pneumatization of the sphenoid sinus along with outward concavity of the inferior portion of the lateral wall. None of these 23 patients had arachnoid pits. CONCLUSION: The sphenoid sinus, when implicated as a site of spontaneous CSF leak, yields a multitude of imaging findings. These are extensive pneumatization of the lateral recess of the sphenoid sinus, outward concave orientation of the inferior portion of the lateral wall of the sphenoid sinus, arachnoid pits, and empty sella. Considering the normative data, we speculate that this constellation of findings could play a role in the etiopathogenesis of spontaneous sphenoid sinus fistulas. Our findings also show the efficacy of noninvasive imaging techniques, such as plain high-resolution CT and MR cisternography, in the evaluation of sphenoid sinus CSF leak. Our data also suggest that spontaneous sphenoid sinus CSF leak is not an uncommon occurrenc     

Lateral wall of the olfactory fossa in determining intracranial extension of sinus carcinomas.

The role of plain skull radiography and pluridirectional tomography in determining anterior cranial fossa extension of paranasal sinus tumors is reassessed. The lateral wall of the olfactory fossa, a thin bony plate forming part of the roof of the ethmoid sinuses, is routinely visualized on plain skull radiography and pluridirectional tomography in the coronal plane and serves as an indicator of intracranial tumor extension. In a series of 47 patients with paranasal sinus tumors, 100% true positive and 3% false negative interpretations of the integrity of the lateral wall of the olfactory fossa were made with pluridirectional tomography. Interpretations with plain skull radiography were 90% true positive and 3% false negative. Assessment of the integrity of the lateral wall of the olfactory fossa by these techniques provides an accurate evaluation of the presence of intracranial tumor extension by this route. Computed tomography in the coronal plane with contrast infusion is a useful adjunct.     

Mechanism of transverse fracture of the skull base caused by blunt force to the mandible

Transverse fracture of the skull base is common both in the crushing of temporal regions of the skull and in the case of force acting on one temporal region. However, the mechanism of transverse skull base fracture caused by maxillofacial force has not been fully clarified. To provide an injury identification basis for forensic pathologists and clinicians, this paper combines accident reconstruction and finite element analysis methods to study the injury mechanism of an incomplete transverse fracture of skull base after the injured individual’s mandible was subjected to violence in a traffic accident. The results show that after the injured individual’s mandible was subjected to violence, forces in the direction of the left mandibular fossa and the right mandibular fossa were generated, creating the component forces. The combination of the two forces can produce a crushing effect toward the center of the skull base, as if the left and right temporal regions are being crushed, and the stress is concentrated at the joint of the mandible, the middle cranial fossa and the hypophyseal fossa. When the stress exceeds a certain limit, it will cause a transverse fracture of the skull base.     

The craniocervical venous system in relation to cerebral venous drainage

BACKGROUND AND PURPOSE: Passing from the supine to the upright position favors cerebral venous outflow into vertebral venous systems rather than into the internal jugular veins. We sought to determine venous connections between dural venous sinuses of the posterior cranial fossa and craniocervical vertebral venous systems. METHODS: Corrosion casts of the cranial and cervical venous system were obtained from 12 fresh human cadavers, and anatomic confirmation was made by dissection of three previously injected fresh human specimens. MR venography was performed to provide radiologic correlation. RESULTS: The lateral, posterior, and anterior condylar veins and the mastoid and occipital emissary veins were found to represent the venous connections between the dural venous sinuses of the posterior cranial fossa and the vertebral venous systems. This study revealed the nearly constant presence of the anterior condylar confluent (ACC) located on the external orifice of the canal of the hypoglossal nerve. The ACC offered multiple connections with the dural venous sinuses of the posterior cranial fossa, the internal jugular vein, and the vertebral venous system. All these structures were shown by MR venography. CONCLUSION: The lateral, posterior, and anterior condylar veins and the mastoid and occipital emissary veins connect the dural venous sinuses of the posterior cranial fossa with the vertebral venous systems. These connections are clinically relevant, because encephalic drainage occurs preferentially through the vertebral venous system in the upright position. The ACC is a constant anatomic structure that may play an important role in the redirection of cerebral blood in the craniocervical region.     

Single- versus multi-detector row CT of the brain: quality assessment

PURPOSE: To assess the quality of brain computed tomographic (CT) studies obtained with a four-channel multi-detector row CT scanner compared with those obtained with a single-detector row CT scanner. MATERIALS AND METHODS: Forty-seven patients referred for brain CT were imaged with both single- and multi-detector row scanners. Single-detector row CT images were acquired by using a 5-mm-collimated beam in the transverse mode. Multi-detector row CT images were acquired in four simultaneous 2.5-mm-thick sections, which were combined in projection space to create two contiguous 5-mm-thick sections. Two neuroradiologists blinded to the acquisition technique independently evaluated the CT image pairs, which were presented in a stacked mode on two adjacent monitors. Each study was graded by using a five-point scale for posterior fossa artifact, overall image quality, and overall preference. RESULTS: Multi-detector row CT studies were acquired 1.8 times faster than single-detector row CT studies (0.92 vs 0.52 section per second). Multi-detector row CT posterior fossa artifact was less than single-detector row CT posterior fossa artifact in 87 (93%) of 94 studies. Overall preference was expressed for multi-detector row CT in 84 (89%) of 94 studies. The differences in mean posterior fossa artifact scores (P <.001) and mean overall image quality scores (P =.001) were significant. CONCLUSION: Brain CT images obtained with multi-detector row CT resulted in significantly less posterior fossa artifact and were preferred to single-detector row CT images.     

Orbital sinus histiocytosis: MR appearance

This case report describes the appearance of orbital sinus histiocytosis by magnetic resonance (MR) imaging. Four years after the remission of unilateral cervical adenopathy due to sinus histiocytosis, a 6-year-old girl developed orbital sinus histiocytosis with extension into the middle cranial fossa. Computed tomography demonstrated a homogeneously enhancing lesion; on MR, this tumor was isointense to gray matter on T1-weighted, proton density, and T2-weighted images. Vascular embarrassment was clearly shown by MR.     

Air in the temporomandibular joint fossa: CT sign of temporal bone fracture

Temporal bone fractures can be difficult to detect clinically and radiographically. Air is sometimes present in the glenoid fossa of the temporomandibular joint (TMJ) at computed tomography (CT) of acute basilar skull fractures. This study evaluated TMJ fossa air as a sign of temporal bone fracture. Initial CT scans of the head in 114 patients with a diagnosis of basilar skull fracture at discharge were retrospectively reviewed. TMJ fossa air was present in 23 of 114 patients (20.2%) and was bilateral in three patients. Only temporal bone fractures were significantly (P less than .001) associated with TMJ fossa air. Temporal bone fractures were observed at CT in 23 of 26 cases of TMJ fossa air, but in three of 26 cases, TMJ fossa air was the only CT sign of clinically apparent temporal bone fractures. TMJ fossa air is associated with acute temporal bone fracture and may be the only CT sign of an otherwise inconspicuous temporal bone fracture.     

Thick-section reformatting of thinly collimated helical CT for reduction of skull base-related artifacts

OBJECTIVE: Our purpose was to evaluate thick-section reformatted helical CT of the brain base as a technique for reducing skull base-related artifacts and to compare it with conventional CT. MATERIALS AND METHODS: Twenty-three patients with suspected intracranial abnormalities related to the brain base, as determined either by clinical examination or at the time of imaging, were evaluated with contrast-enhanced conventional CT of the brain (5-mm collimation, 140 kVp, 170 mA, 2-sec rotation time) and reformatted helical CT (1-mm collimation, 1.5 pitch, 120 kVp, 220 mA). Helical sections were reformatted to a thickness of 5 mm by a volume-averaging algorithm using a computer workstation. Three observers retrospectively and blindly reviewed the images and qualitatively scored artifacts at the foramen magnum, middle cranial fossa, anterior cranial fossa, interpetrous region, and internal occipital protuberance. Image graininess and observer confidence were also scored. Paired statistical analyses using score differences in each patient were possible. RESULTS: Reformatted helical CT reduced skull base-related artifacts across all five anatomic regions (p < 0.05). The foramen magnum showed the greatest reduction in artifacts and the anterior cranial fossa the least. Image graininess was increased on reformatted CT compared with conventional CT (p < 0.05), but observer confidence remained higher for reformatted CT (p < 0.05). Total additional scan time was 3.15 +/- 0.38 min with 5.3 +/- 1.2 min required for reformatting. CONCLUSION: Reformatted CT significantly decreases skull base-related artifacts in the brain, improving confidence in evaluation of the brain base and adding an average of only 8.45 +/- 1.6 min of scanning and processing time to each examination.     

Dural arteriovenous malformations at the base of the anterior cranial fossa: report of nine cases

Nine men with dural arteriovenous malformations (DAVM) at the base of the anterior cranial fossa are described. Four patients had intracerebral haemorrhage and four had seizures, associated with haemorrhage in two. In three cases the fistula was an incidental finding. In five cases the diagnosis could be made before angiography, on the basis of CT findings. Angiographically, venous drainage was always seen into ascending cortical veins. Five cases demonstrated drainage via the olfactory vein into the basal vein of Rosenthal; in four this way was the principal route of drainage. Five patients underwent surgery, the therapy of choice. One fistula closed spontaneously after angiography. Two patients refused treatment and one was not treated because of his poor general condition. Because arterial supply was usually bilateral, from small branches of the ophthalmic artery, embolisation seemed to be more dangerous. Compared to dural fistulae in other locations the DAVM of the anterior cranial fossa have a higher risk of complications and should be treated even if asymptomatic at the time of diagnosis.     

Patterns of skull base fracture: a three-dimensional computed tomographic study

Three-dimensional (3D) computed tomographic (CT) reconstructions were studied retrospectively in 14 patients with skull base fractures. Our aim was to assess the clarity of visualisation and pattern of these fractures. The reformations were obtained from 3 mm thick two-dimensional (2D) CT images. The 2D data stored on optical discs were retrieved and reformatted using the scanner's software. The 3D technique could demonstrate the presence of fractures as well as 2D images. It was of special value in defining the depth and extent of fractures in the floor of the cranial fossae. Undisplaced and displaced fractures could both be demonstrated. Fractures in the anterior fossa run diagonally towards the midline and then cross the cribriform plate of the ethmoid bone. Fractures of the middle fossa run obliquely anteroposterior. Fractures in the lamina papyracea and cribriform plate were difficult to reconstruct due to the the thinness of these bones and threshold definitions. The volume of the 3D block determines the angles suitable for viewing the fractures. In spite of present technical difficulties, the 3D images are of greater anatomical and diagnostic value, particularly in anterior fossa fractures. There is no additional radiation risk to the patient, since reconstructions are made from routine 2D images.     

Choroid plexus papilloma in the posterior cranial fossa: MR, CT, and angiographic findings.

In this study, we reviewed the magnetic resonance (MR, n=5), computed tomography (CT, n=3), and angiography (n=3) of six patients with pathologically confirmed choroid plexus papilloma (CPP) in the posterior cranial fossa. CPPs in the posterior cranial fossa have several features, including a propensity to arise at the foramen of Luschka with extraventricular extension, occasional peritumoral signal voids/cysts or calcification, weaker enhancement on MR or CT, and less strong tumor staining by the anterior or posterior inferior cerebellar artery or angiography.     

Sonographic visualization of neonatal posterior fossa abnormalities through the posterolateral fontanelle

OBJECTIVE: This study was performed to determine whether imaging through the posterolateral fontanelle in addition to the anterior fontanelle during neonatal cranial sonography improves diagnostic accuracy or examiner confidence in the diagnosis of neonatal posterior fossa abnormalities. MATERIALS AND METHODS: In 1995 we changed our protocol of neonatal cranial sonography to include imaging through the posterolateral fontanelle in all patients. The reports of all sonography performed in the first 15 months of this protocol were reviewed, and two radiologists reviewed the images of all patients in whom a posterior fossa abnormality was diagnosed with posterolateral fontanelle images masked and then with posterolateral fontanelle images available. RESULTS: In total, 1292 sonograms were obtained in 462 patients. In 200 patients, the sonographic findings were abnormal; of these 200 patients, 24 (12%) had posterior fossa abnormalities (nine posterior fossa hemorrhages, four Arnold-Chiari malformations (type II), two posterior fossa arteriovenous malformations, and nine partial vermian defects). The posterolateral fontanelle images showed the posterior fossa abnormality better than the anterior fontanelle images did in 23 (96%) of the 24 patients, increased confidence in the diagnosis of 18 (75%) of the 24 patients, and was the only technique to reveal the posterior fossa abnormality in 11 (46%) of the 24 patients. Nearly all pathologic correlations with imaging confirmed the posterolateral fontanelle findings except for the diagnosis of inferior vermian agenesis, which was presumed to be a false-positive diagnosis in four patients in whom MR imaging showed no abnormalities. CONCLUSION: Additional imaging through the posterolateral fontanelle during routine neonatal cranial sonography added considerable benefit. False-positive diagnosis of vermian defects is a troubling problem but may be avoided with careful attention to the midline sagittal sonographic images of the vermis and fourth ventricle.     

Patellar resection during total knee arthroplasty: effect on bone strain and fracture risk

Patellae in small knees, or after severe patellar erosion, may be vulnerable to fracture after resection during arthroplasty. The patellar remnant may be thin, while the polyethylene component has a standard thickness. Anterior patellar bone strain was measured in cadaver knees loaded via the quadriceps, from 0 to 90° flexion, with the patella intact, and after resections to 16, 13 and 11 mm thick and replacement by an 8-mm-thick polyethylene component. Strain increased significantly with knee flexion with constant 500 N quadriceps tension. Resection caused significant changes from intact values in knee flexion and extension and no significant effect at 30° flexion. In flexion, bending caused the anterior surface to become more convex, with high tensile bone strains. In extension, resection caused negative anterior strains, representing bending in the opposite direction, with large tensile strains on the cut posterior surface. For normal activities, such as rising from a chair (1.8 kN quadriceps tension) the patella appears safe against fracture with a minimal resection to 16 mm thick. An eroded patella resected to 11 mm thickness may be at risk of fracture with that loading.     

The hypoglossal canal: normal MR enhancement pattern.

PURPOSETo review the anatomy of the hypoglossal canal and present the normal precontrast and postcontrast MR appearance of axial posterior fossa images.METHODSThirty-one axial MR examinations of the normal posterior fossa were retrospectively reviewed.RESULTSThe hypoglossal canals are well seen on 3-mm-thick axial MR images of the posterior fossa (28 [90%] of 31 patients). Symmetric intense intracanalicular enhancement after intravenous administration of gadopentetate dimeglumine is routine, typically with minor anterior extension into the nasopharyngeal region (28 [100%] of 28). A linear filling defect traversing the enhanced canal often is seen (21 [75%] of 28) and may represent hypoglossal nerve rootlets. Circumferential enhancement of the meninges at the level of the foramen magnum was a common finding (19 [64%] of 28).CONCLUSIONEnhancement within the hypoglossal canal with anterior extension beneath the skull base is a normal finding. This pattern is characteristic enough on MR imaging to aid interpretation of skull base lesions and to exclude the possibility of a mass within the hypoglossal canal.