Biomedical subjects
Publications and source records attributed to L Penning.
Preoperative localization of a tumor on the scalp can be achieved with the help of computerized tomography (CT) but is liable to error. A simple method is presented to relate the data provided by the CT scan precisely to the scalp of the patient.
In a series of 62 patients with cervical nerve root symptoms CT myelography of the cervical spine revealed specific radiological signs in 24 patients. These signs are: stenosis of the spinal canal, nerve root swelling and/or soft disc herniation. Disc bulging or spondylotic encroachment with only partial narrowing of the myelographically visible part of the foramen, and often unilateral flattening of the cord is considered clinically insignificant. A normal appearance of cord and nerve roots was seen in 22 patients.
CT myelographic data in 80 patients with clinical evidence of nerve-root involvement or long tract signs attributed to degenerative disorders of the cervical spine were classed into five diagnostic groups, and their clinical significance was assessed. Unilateral flattening of the cord by a spondylotic mass or bulging disk in a normally wide canal (group 1) was considered nonspecific because nerve-root signs were nearly as often contralateral as unilateral to the radiologic findings, and none of the patients had long tract signs. As a rule, conventional myelography showed only minor root-sleeve deformity. Concentric compression of the cord in a narrow (stenotic) canal (group 2) proved to produce long tract signs only after the cross-sectional area of the cord had been reduced by about 30% to a value of about 60 mm2 or less. In most cases, nerve-root swelling (group 3) coincided with the side of nerve-root symptoms. A 100% correlation was found between the side of disk herniation with occlusion of the corresponding foramen (group 4) and the side of nerve-root symptoms. In 24 patients, cord and nerve roots showed no abnormalities (group 5). If stenosis of the spinal canal, nerve root swelling, and disk herniation are considered specific CT myelographic signs in nerve-root symptomatology, a specific diagnosis could be made in about 40% of the cases.
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Myelographic flexion-extension studies were performed in four groups of 10 patients each, with (A) normal myelogram; (B) bilateral nerve root compression at L4-L5; (C) unilateral nerve root compression at L4-L5 and (D) nerve root compression at L5-S1. The aim of the investigation was to assess the role of spinal stenosis in contributing to nerve root compression. The results indicate that a form of stenosis of the spinal canal plays an important role in bilateral nerve root compression at L4-L5, and to a lesser extent in unilateral nerve root compression at L4-L5. It does not appear to play a role in L5-S1 nerve root compression (stenosis of the lateral recess left aside). It is advocated that in myelographic L4-L5 nerve root compression additional flexion-extension studies should be performed in order to evaluate the possible role of stenosis of the spinal canal contributing to this compression. Even in nerve root compression by disc extrusion, concomitant spinal stenosis may necessitate additional decompressive laminectomy.
In two groups of patients with low back pain radiological flexion-extension studies were made (one in the standing position, the other in the lateral decubitus position), and the degree of mobility and location of instantaneous centres of motion determined between L2 and the sacrum. The study failed to demonstrate distinctly abnormal patterns of motion ('instability'). The main reason is that such problems, as shown in the biomechanical laboratory, are not reproduced in the clinical setting. Smaller abnormalities will remain undetected because of measurement errors of the method, making differentiation between normal and abnormal motion virtually impossible.
Presentation of a case of thoracic OPLL in a non-Japanese woman with myelographic abnormalities at both the cervical and thoracic levels, and widespread spinal manifestations of DISH.
With a technique described earlier, but modified by special positioning of the patients and use of water-soluble contrast medium, we managed to pass an apparently total spinal block in 11 out of 14 patients. Apart from a shortlasting pain during the procedure, the patients suffered no harm. The duration of the examination could be shorter and less patient cooperation was necessary.
In a consecutive series of 30 hospitalized cervical injury patients, 18 proved to have widening of the prevertebral soft tissue space due to hematoma. The upper limit of normal width in 50 noninjury patients was used as a reference. Hematoma almost exclusively manifested at C1-C4 and proved to be closely related to fractures of anterior elements of the spine. Relatively small hematomas were encountered in odontoid fractures and compression fractures of vertebral bodies; relatively large hematoma in disruptive hyperextension injury. Large hematomas are explained by extensive anterior ligamentous damage with rupture of larger blood vessels. As a rule, most hematomas disappeared within 2 weeks after the injury.
An attempt was made to define more precisely the notion of spine instability in lumbar spondylolisthesis. By means of lateral radiographs in flexion and extnsion, the axes of movement and the degree of mobility at the L3--L4, L4--L5, and L5--S1 levels were determined in 24 cases of true (spondylolytic) spondylolisthesis. Axes of movement at the spondylolisthetic levels showed a somewhat larger spread in and around the discs than at the normal levels, but instability in the form of parallel displacement of vertebral endplates was not observed. Hypermobility at the spondylolisthetic level proved to be a regular finding. The still current concept of "instability" as presented by Knutsson in 1944 was critically reviewed and denied as valid. Imprecision in the literature regarding instability may partly be attributed to insufficient discrimination between vertebral displacement as anatomic relationship and as abnormal type of movement. By designing a two-dimensional model other movements than flexion-extension could be studied; a special form of instability at the spondylolisthetic level was shown to appear during forward and backward movement of the lumbar spine above it. This detailed analysis facilitates understanding of the effect of different surgical procedures on vertebral movement and instability in lumbar spondylolisthesis.
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Metrizamide, a non-ionic contrast medium of low osmolality was compared with meglumine ioxithalamate, the ionic angiographic contrast medium currently in use in our department in a double-blind study. Criteria upon which the comparison was based were: 1) the pain reaction of the patient upon intra-arterial contrast injection, 2) bradycardial reactions upon common carotid injection and 3) the quality of the contrast image. Metrizamide induced significantly less painful sensations than meglumine ioxithalamate in those vessels in which injections of contrast medium are frequently painful (external carotid artery, vertebral artery). No significant difference in the degree of bradycardia was caused by the two contrast media. The degree of bradycardia was also found to be poorly reproducible upon successive injections of the same contrast medium in the same patient, thus raising questions as to the suitability of this method for determining the toxicity of the contrast medium. The quality of the angiograms obtained did not differ significantly with the two media. Spasm, when it occurred during selective external carotid injections, was found to be independent of the contrast agent used, being correlated instead with the depth of distal advance of the catheter tip into the external carotid. Of the 51 patients included in the study, two patients suffered transient neurological deficit after angiography with metrizamide, and one patient suffered a permanent hemiplegia after angiography with meglumine ioxithalamate.
For lumbar epidural phlebography an even distribution of the injected contrast medium over the epidural and intervertebral venous system is of the greatest importance in order to prevent the false positive diagnosis of a lumbar disk lesion due to an artificial filling defect. Various catheter placement techniques and other procedures designed to enhance epidural opacification are compared in this respect. In the author's opinion, selective injection of the contrast medium into an intervertebral vein, when possible, leads to the most reliable epidural filling.
This paper describes a technique for analyzing movement of the cervical spine. The method consists of superimposition of two films representing the cervical spine in the end positions of the movement under investigation (e.g., flexion and extension). From tracings of selected structures, movement is represented in the form of movement diagrams. Knowledge of cervical spine dynamics is helpful in understanding muscle and ligament function as well as the shape of components in various postures.
CSF ex vacuo is a proposed designation for abnormal collection of CSF replacing brain tissue which has been lost by trauma, infection, hemorrhage etc., or which has not been developed e.g. in aplasia of the temporal lobe. Such collections are known as arachnoid, leptomeningeal or porencephalic cysts. Under certain, however unsufficiently understood, conditions CSF ex vacuo may develop expansive tendencies, most obvious in growing fracture of the skull vault or base. In unexplained recurrent meningitis the presence of a frontobasal CSF collection should be looked for.
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Explore the source record for details and available documents.