Temporal bone fractures.

High-resolution technique is essential to the evolution of temporal bone fractures. Axial and coronal scan planes are optimal but may not be possible in acutely traumatized patients. A knowledge of normal temporal bone anatomy is important and can be obtained from standard texts, so it will not be considered in detail in this article. Classically, petrous temporal bone fractures have been classified as longitudinal, transverse, or mixed. Recent publications have emphasized the importance of describing fractures in terms of planes rather than lines. According to this concept, most temporal bone fractures are actually oblique, and true longitudinal fractures are rare. Petrous temporal bone fractures may be associated with cranial nerve or vascular injuries when the fracture extends to the skull base. This is particularly true of the oblique fracture, which characteristically extends anteromedially to the skull base through weak places in that area, thus avoiding the compact bone of the otic capsule surrounding the labyrinth. The most common associated injury is to the facial nerve in its geniculate or proximal tympanic segment. Transverse fractures frequently involve the labyrinth. A careful search for various types of ossicular dislocation should be performed in association with temporal bone fractures, because this may result in conductive hearing loss. The site of cerebrospinal fluid otorhinorrhea resulting from temporal bone fractures can usually be defined on plain high-resolution temporal bone images, but intrathecal contrast may be helpful. Temporal bone fractures caused by gunshot wounds are frequently complex and may be limited by metallic streak artifacts. Pediatric patients have different proportions of facial nerve injury and types of hearing loss as compared with adults.

Rolandic type cerebral palsy in children as a pattern of hypoxic-ischemic injury in the full-term neonate.

Magnetic resonance images (MRIs) of the brains of 11 patients aged from 1 week to 12 years with a distinctive type of cerebral palsy were selected based on distribution of cerebral lesions, which were restricted to bilateral perirolandic cortical and subcortical regions, including frequent symmetric involvement of basal ganglia and ventrolateral nucleus of thalami. Retrospectively, the perinatal history and clinical features were reviewed to correlate clinical data with this distinctive pattern of brain injury. Clinically affected neonates had an encephalopathy associated with a severe perinatal asphyxial event. Older children with cerebral palsy survived a similar perinatal course and demonstrated spastic quadriparesis with bulbar or pseudobulbar involvement, lack of verbal speech and variable delays in cognitive development. The distribution of hypoxic-ischemic lesions involving bilateral perirolandic regions, basal ganglia, and thalami, appears to correlate with increased metabolic areas of primary myelination in full-term neonates, but not with arterial border zones nor a single cerebral artery distribution. Myelination is a critical process in maturing brain associated with marked increase in tissue respiration and thus greater susceptibility to oxygen deprivation. It is believed that the extent of hypoxic-ischemic brain injury is determined principally by brain maturity and regional metabolic rates at time of insult and this correlates with active myelination in full-term neonates. This study confirms previous data from neuropathologic literature and recent reports of neuroimaging studies of asphyxiated neonates. In addition, retrospective analysis of the clinical data enables recognition of a type of cerebral palsy that might be the hallmark of hypoxic-ischemic injury in term neonates.

CT evaluation of congenital aural atresia: what the radiologist and surgeon need to know.

PURPOSE: The preoperative evaluation of aural atresia and stenosis is strongly dependent upon high resolution CT. We have devised a 10 point surgical rating scale based on high resolution CT of the temporal bone that will provide radiologists with a stepwise method of evaluating these scans and will allow them to communicate these findings to otologic surgeons in a consistent fashion. METHOD: We prospectively evaluated 1,500 patients with aural atresia or stenosis for eight critical areas of temporal bone anatomy, each area receiving 1 rating scale point, with the exception of the presence of a stapes, which received 2 points. The appearance of the external ear received the final point on the rating scale since the external ear is formed earlier than the middle ear and helps to predict its deformities. The presurgical score was utilized in selecting surgical candidates and was correlated with the intraoperative findings as well as the postsurgical results by comparing pre- and postoperative speech reception threshold. Patients with a presurgical rating of < or = 5 were not considered surgical candidates. Otherwise, the percentage of successful surgeries corresponded roughly to the rating scale. RESULTS AND CONCLUSION: Thus, a presurgical rating of 8 points translates into an 80% chance of restoring hearing to normal or near-normal levels.

The "Y" sign of lateral dislocation of the incus.

This report presents a new sign of ossicular dislocation utilizing high resolution computed tomography of the temporal bone. In the case of lateral dislocation of the incus, a "Y" shaped configuration (Y sign) of the malleoincudal complex is seen in the coronal views even though the axial views present a normal "ice cream cone" configurations.

Acute hemorrhagic leukoencephalitis: a cause of acute brainstem dysfunction.

A 37-year-old female physician was admitted to the hospital with severe headache, facial and hand paresthesias, dysarthria, and ataxia. Neurologic examination disclosed signs of brain stem dysfunction. There was rapid neurologic deterioration, and she died in 28 hours. Postmortem studies showed the characteristic features of acute hemorrhagic leukoencephalitis.

Surface contour three-dimensional imaging in congenital aural atresia.

Sixty-five patients with congenital aural atresia-stenosis had three-dimensional reconstructions of their high-resolution computed tomographic scans. Surface anatomy of the temporal bone was readily demonstrated, including its relation to the temporomandibular joint. Three important findings were noted. (1) Contrary to popular belief, the condyle of the mandible does not rest against the anterior face of the mastoid bone. (2) A bony cleft or groove is often in the lateral temporal bone through which the facial nerve may exit. (3) Duplications of bony structures attached to or part of the temporal bone are clearly defined. The information gained from the routine use of three-dimensional imaging of the computed tomographic scan alerts us to potential intraoperative problems that may otherwise escape our scrutiny, particularly if only two-dimensional computed tomographic scanning is done.

Subdural hygroma versus atrophy on MR brain scans: "the cortical vein sign".

PURPOSE: To determine if the position of the superficial cerebral cortical veins can be used to distinguish subdural hygroma from atrophy on MR brain scans. METHODS: Retrospective review of MR scans obtained in cases of extracerebral fluid collections, separating these into two groups, ie, subdural hygroma or atrophy. FINDINGS: All cases of atrophy in this study showed cortical veins and their branches traversing widened cerebrospinal fluid spaces over the cerebral convexities. None of the subdural hygroma patients showed this finding. Cortical veins in hygroma patients were seen only at the margin of the displaced cortex, and did not traverse the fluid collections over the cerebral convexities. CONCLUSIONS: The authors call the visualization of cortical veins and their branches within fluid collections at the cerebral convexities "the cortical vein sign." They believe this sign to be prima facie evidence of atrophy; its presence rules out the diagnosis of subdural hygroma in the region of interest.

Orbital blowout fractures as a cause of sinonasal obstructive disease.

Six cases of orbital blowout fracture with inferomedial herniation of orbital contents into the sinonasal ostiomeatal unit causing obstruction to maxillary sinus outflow are presented. Potential hazards during endoscopic sinus surgery in these cases are outlined.

Hyperextension-dislocation of the cervical spine. Ligament injuries demonstrated by magnetic resonance imaging.

We reviewed the magnetic resonance (MR) images of eight adults with acute hyperextension-dislocation of the cervical spine. The images were obtained to evaluate damage to the spinal cord. All eight patients had disruption of the anterior longitudinal ligament and of the annulus of the intervertebral disc, and separation of the posterior longitudinal ligament from the subjacent vertebra. Some, but not all, showed widening of the disc space, posterior bulging or herniation of the nucleus pulposus, and disruption of the ligamentum flavum. The MR demonstration of these ligament injuries, taken with the clinical and radiographic findings, establishes the mechanism of hyperextension-dislocation, confirms the diagnosis, and is relevant to management.

Bilateral neonatal Sturge-Weber-Dimitri disease: CT and MR findings.

The CT and MR features of cortical calcification and meningeal angiomatosis are typical of Sturge-Weber-Dimitri disease but are unusual in children less than 1 year of age. This case describes a child presenting with both of these features bilaterally in the neonatal period and represents an unusual presentation of this disorder.

Pediatric temporal bone fractures.

Twenty-seven temporal bone fractures in 25 pediatric patients were evaluated over a 6-year period. The diagnosis was confirmed with otoscopy and high-resolution computed tomography scans (HRCT). Three-dimensional reconstruction of high-resolution computed tomography scans were used to aid in the diagnosis. The most common fracture was an oblique fracture which is oriented in an axial or horizontal plane with the temporal bone. Facial nerve paralysis was found in 6 of our patients, which is less than the expected incidence when compared to adults. Hearing loss was found in 24 patients, the most common of which was conductive hearing loss, which had a higher incidence than expected when compared with adults.

Temporal bone fractures: longitudinal or oblique? The case for oblique temporal bone fractures.

Classical descriptions and illustrations of temporal bone fractures are misleading. Both oblique and longitudinal fractures produce a similar fracture line in the middle cranial fossa; however, externally, they are different. Oblique fractures cross the petrotympanic fissure while longitudinal fractures run within it. In a study of 150 temporal bone fractures, the majority were oblique. An array of fracture planes accounts for most of the fractures observed. Depending on the direction of trauma, fracture planes rotate around an anteroposterior axis. When they approach the horizontal (axial) plane, they result in oblique fractures. True longitudinal fractures are rare. They are vertical and perpendicular to the oblique planes.

Grading system for the selection of patients with congenital aural atresia.

It is generally recognized that surgery for congenital aural atresia is difficult. In an effort to select those patients who have the greatest chance of success, we have developed a grading scheme based on the preoperative temporal bone CT scan and the appearance of the external ear. Patients are graded on a possible best score of 10. The stapes is assigned the highest rating (2 points), while all other entrees on the scale are 1 point. The grade assigned preoperatively has been shown to correlate well with the patient's chance of success, herein defined as a postoperative speech reception threshold of 15 to 25 dB. A patient with a preoperative grade of 8/10 would, therefore, have a 80 percent chance of achieving this threshold. Patients with scores of 5/10, or less, are not considered surgical candidates, because the risk of the operation would outweigh the potential benefits. We have found that the grading system allows us to avoid impossible surgical cases while allowing for a reasonable prediction of the hearing outcome.