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Biomedical subjects

H Verbiest

Publications and source records attributed to H Verbiest.

At least 19 recordsLinked to original sources
PubMed1997

The facet orientation circle. A new parameter for facet joint angulation in the lower lumbar spine.

STUDY DESIGN: A descriptive quantitative evaluation was done of the transverse orientation of the lower lumbar facet joints as measured by computed tomography scanning. OBJECTIVES: To evaluate a new parameter for facet joint angulation in the transverse plane (the "facet orientation circle") and to obtain reference values for this new parameter. SUMMARY OF BACKGROUND DATA: In other studies, both in vitro and in vivo, the angulation of the facet joints has been measured in degrees relative to the frontal or sagittal plane. These methods have some limitations. The parameter used in the present study has not been described in the literature. METHODS: Lower lumbar facet joint orientation was measured in 212 vertebral levels of 123 consecutive patients using the facet orientation circle parameter. Patients with degenerative or developmental abnormalities of the lumbar spine were excluded, as were those with technically inadequate computed tomography studies. RESULTS: Mean facet orientation circle diameters (+/-SD) were: L3-L4, 43.7 +/- 10.5 mm; L4-L5, 63.8 +/- 26.4 mm; and L5-S1, 82.3 +/- 23.5 mm. Differences between right and left sides were: L3-L4, 6.3 +/- 7.1 mm; L4-L5, 13.9 +/- 25.3 mm; and L5-S1, 17.9 +/- 16.2 mm, intra-observer variability was 2.3%. CONCLUSIONS: Measurement of facet joint angulation using the facet orientation circle is possible and reproducible. The morphometric data presented may be useful as a reference for biomechanical and clinical research of facet joint orientation and asymmetry.

Adolescent↗
PubMed1996

Delayed radiation myelopathy: serial MR-imaging and pathology.

Clinical data, MR-scans, time-dose fractionation schemes and neuropathologic findings of two cases of delayed radiation myelopathy (DRM), are presented. Both patients, a 72-year-old diabetic woman with cervical lymphnode metastasis from a squamous cell carcinoma and a 46-year-old woman with tonsillar carcinoma, developed paraparesis followed by quadriplegia, at 7 and at 10 months following radiation. The spinal cord received 46 and 49 Gy. (Fraction dose 2.25 Gy and 2.0 Gy, 4 times/week). Serial MR-scans showed spinal cord enlargement and focally increased signal intensity (T1-gd). The second patient survived and stabilized following therapy with coumarins. The first patient died 13 months after radiotherapy. At autopsy necrosis, local calcium deposits, lipid macrophages and swollen astrocytes were observed in the white matter. There was slight hyalinosis of the intramedullary vessel walls. We conclude that serial MRI may be helpful to distinguish DRM from other causes of spinal cord injury. DRM may occur at a total dose less than 50 Gy. Additional risk factors (diabetes, hypertension), and fraction doses above 2 Gy contribute to the development of DRM.

Aged↗
PubMed1994

Removal of aneurysmal bone cyst in the area of C1, C2 and foramen magnum. Follow-up of surgical osteoplastic repair by means of 3 D CT studies 15 years later.

First, the author relates his memories of his first encounter with the new Editor-in-Chief of the Acta Neurochirurgica in 1957 and the reasons why it made such an unforgettable impression. Next, follows a discussion of the technical difficulties in the treatment of spinal aneurysmal bone cysts, which may produce extensive destruction of its bony elements. The relatively rare occurrence of these lesions and resulting limited experience provide insufficient grounds for developing rigid rules of surgical treatment. Their treatment must rather rely on experience by means of examples (paradigms). The present author's principles of surgical strategy are total removal of these cysts and repair by means of stabilizing bony autotransplants. A description is given of an unusual case of an aneurysmal bone cyst localized in the cervical-occipital transition area in which 3 D CT images give a better view on stabilization reached by osteoplastic repair of the destroyed structures than can be achieved with previous imaging methods.

Bone Cysts, Aneurysmal↗
PubMed1989

Isolated spinous process deviation. A pitfall in the interpretation of AP radiographs of the lumbar spine.

A new type of spinous process deviation is described. This variant may cause confusion in the interpretation of anteroposterior (AP) radiographs of the lumbar spine. In the literature, two types of lumbar spinous process deviation (SPD) have been described: 1) SPD due to rotation of the entire vertebra (as in rotatory scoliosis and degenerative arthritis), and 2) SPD as a consequence of developmental asymmetries of the neural arch. The present study demonstrates that spinous process deviation in the AP radiograph is not a reliable diagnostic guide. The authors' quantitative morphologic analysis of computed tomographic (CT) sections of over 200 lower lumbar vertebrae in vivo revealed a third type of SPD, namely isolated deviation of the spinous process, ie, deviation without any associated rotation or asymmetry of the vertebral body or arch. Since the oval shadow cast by the spinous process in AP radiographs is caused by its tip, rather than by its base (as was demonstrated by in vitro tests), it is concluded that the position of the spinous process shadow in AP radiographs cannot be used as a reliable landmark to differentiate between the three types of SPD. This is only possible by means of a CT examination.

Diagnosis, Differential↗
PubMed1985

Morphometry of lower lumbar vertebrae as seen on CT scans: newly recognized characteristics.

Transaxial computed tomographic (CT) sections represent a new approach to vertebral morphometry, allowing certain measurements to be made in vivo for the first time. The cross-sectional morphology of the bodies and pedicles of L3, L4, and L5 was studied in a series of 213 vertebrae. This revealed that the pedicles of L5 arise more laterally from the body of L5 than from L3. Further, the lateral surfaces of the L5 body are inclined obliquely, unlike those of L3. L4 is transitional in form between L3 and L5, more closely resembling the former. This morphology explains the fact, hitherto unnoticed, that the lateral outlines of the pedicles and the lateral borders of the body of L5 are not normally imaged on plain anteroposterior radiographs. It is evident that pathologic changes of the lateral borders of the body of L5 may be invisible also. In cases of transitional vertebrae in the lumbosacral region the presence or absence of the lateral outlines of the pedicles and of the lateral borders of the vertebral body may be of help in identifying the vertebrae on conventional projections.

Adolescent↗
PubMed1980

Stenosis of the lumbar vertebral canal and sciatica.

Stenosis of the vertebral canal is a form of compressive stenosis in contrast to transport stenosis of vessels or other channels. The concept, definition and pathomorphological properties are discussed. As it is a form of compressive stenosis, the diagnosis is based on measurements of diameters rather than of cross-sectional surfaces. The biomechanical action of compressive stenosis is compression of the fixed living content at two opposite sites or at all sites. The special properties of sciatica in stenosis are described and presented in tabular form. Some properties of neurogenic intermittent claudication (I. Cl.) in the presence of stenosis are discussed. There is a predominance of sciatica at rest and of motor weakness during walking. The mechanism of neurogenic I. Cl. is obscure. Stenosis of the lumbar vertebral canal is one of the conditional determinants of I. Cl. The data presented in this paper demonstrate, however, that stenosis is not an absolute determinant of I. Cl. and that its production depends on the combination with other determinants. The theory is advanced that other determinants may be related to changes in the caudal nerve roots due to either constitutional properties or to subclinical changes induced by ageing and chronic wear and tear, and compression and traction in the area of stenosis during various bodily activities. Suppression of sciatica during I. Cl. is a phenomenon which is particularly difficult to explain.

Anthropometry↗