Endplate Deformation Research Articles

The effect of nucleotomy on lumbar spine mechanics in compression and shear loading.

An in vitro biomechanical investigation on human cadaveric specimens was conducted before and after nucleotomy. Endplate and vertebral body deformation patterns were measured under compression and shear loading, in addition to kinematics and disc pressure. The working hypotheses of this study were that in compression, nucleotomy results in an altered deformation pattern of the endplate and that in shear, nucleotomy does not result in an altered endplate deformation pattern or disc pressure. The pressure distributions within the intervertebral disc have been studied in compression loading but not in shear loading. Severe degeneration and surgical nucleotomy result in small nuclear pressure and altered loading distribution in compression. The effect of these changes on the vertebral endplate and the response under shear loads are not well understood. Five L3-L4 and two L4-L5 functional spinal units were tested under compression and shear loading, intact and after nucleotomy. Vertebral body deformations, intradiscal pressure, and intervertebral kinematics were measured. A series of compression-type (maximum 1000 N) and shear-type (maximum 500 N) loads were applied. With nucleotomy, the disc pressure and the endplate strains decreased under compression, but the vertebral rim strains did not change. In shear, the vertebral rim and endplate strains did not change with nucleotomy. Disc pressure was lower in shear than in compression. Nucleotomy resulted in decreased disc pressure, decreased endplate deformation, and modified loading patterns onto the inferior vertebra in compression loading. However, nucleotomy did not appreciably affect the behavior of the disc in shear loading.

Electrostatic digital method of wire tension measurement for KLOE drift chamber

For the first time an electrostatic method of wire tension measurement (WTM) is used for drift chamber construction. It became possible due to the use of a digital approach to sense the wire oscillations induced by an alternating potential. The method has excellent signal-to-noise ratio, high accuracy which is well above the stringing requirements and reasonable measuring time. The WTM system implemented in a CAMAC–Machintosh–Labview environment is now in use for the KLOE drift chamber stringing control and for monitoring the end-plate deformation.

Computer modelling of an extended end-plate bolted connection

A methodology, based on finite element modelling, is studied to develop analytically the moment-rotation relationship for a steel bolted end-plate connection. ANSYS, a large-scale general-purpose finite element code is selected for equivalent two-dimensional (2-D) analysis. The end-plate, beam and column flanges, web and bolt shanks in the tension region are represented as plane-stress elements with their width equal to their thickness measured perpendicular to the web. Interface elements are used to model the boundary between column flange and rear of end-plate that may make or break contact. Based on deformation and stress contours of a 2-D model the contribution of beam web to the behaviour is discussed from which two types of end-plate deformation can be identified. The methodology is demonstrated for an extended end-plate connection and the results are compared against experimental data to verify the feasibility of the modelling and associated computer analyses.

Vertebral-body collapse in focal and diffuse disease: patterns of pathologic processes.

The radiographic patterns of vertebral-body collapse and/or endplate deformity were examined in 99 autopsy specimens of the thoracolumbar spine with benign and malignant disease. Angling of endplates was found to be highly predictive of underlying malignancy, whereas concavity was more suggestive of benign disease, for both individual vertebral bodies and intact spines (P less than .001). Diffuse-concave, diffuse-angled, and focal-angled patterns were more useful (P less than .001) than the focal-concave pattern (P = .07) in distinguishing between benign and malignant disease for superior endplates, whereas all were equally useful (P less than .025) in inferior endplates. Condition of the adjacent disks, location within the spine, and position of the apex of collapse were not predictive. Although these results and subsequent blinded testing suggest that reliable distinction between benign and malignant vertebral collapse is possible, extrapolation to clinical practice may be inappropriate because of population bias in the study and differences in radiographic quality between autopsy specimens and live subjects.

"Step-off" vertebral body: Gaucher's disease versus sickle cell hemoglobinopathy.

Two patients with Gaucher's disease and radiographic findings in the spine similar to sickle cell hemoglobinopathy are reported, making a total of four known patients with Gaucher's disease who have these steplike vertebral endplate deformities. Serial films of a patient having Gaucher's disease compared with patients having sickle cell hemoglobinopathy suggest that different events lead to formation of the vertebral deformities. In Gaucher's disease, there is an initial collapse of the entire vertebral body with subsequent growth recovery peripherally. In sickle cell hemoglobinopathy, the endplate deformity is nontraumatic and is caused by an underlying growth arrest.

Roentgen chest findings in childhood sickle cell anemia. A new vertebral body finding.

One hundred and twenty-six sets of posteroanterior and lateral chest roentgenograms were reviewed on 98 Negro infants and children with proven hemoglobin SS sickle cell anemia, and the findings were tabulated in reference to 3 age groups of equal number.With advancing age there was an increase in the percentage of cases showing coarsening of bone architecture, vertebral body end-plate deformity (fish vertebra), and pleural reaction. The incidence of splenomegaly decreased slightly. No age difference was evident in the incidence of hepatomegaly, cardiomegaly, pneumonia and hilar congestion.The vascular notch seen normally on the anterior aspect of the lower thoracic vertebral bodies was often larger, persisted longer, and was more readily seen on the lateral chest roentgenogram in children with sickle cell anemia than in other Negro[See figure in the pdf file]children. The prominence of this notch was most noticeable in the age range from 3 years through 6 years, when it was of most diagnostic importance.W...