ISSN:0362-2436    

出版商:OVID    

年代:1980

数据来源: OVID

ISSN:0362-2436    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

This paper records measurement of the lumbar spinal canal by diagnostic ultrasound in more than 700 subjects from early infancy until the age of 65 years. It demonstrates the range of canal size in a South Yorkshire population. The canal is relatively wide in children, reaches a maximum diameter in the late teens, and reduces slightly by late adult life. This does not appear to be related to occupation. Comparisons are made with more than 700 patients with symptoms of back pain, especially patients with disabling disc symptoms, root entrapment syndrome, and neurogenic claudication. The size of the central canal is particularly significant in patients who have neurogenic claudication and disc symptoms. It is less significant in root entrapment syndrome.

ISSN:0362-2436    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

A simple model is presented that explains the observed function and failure of the intervertebral disc in compression, torsion, and bending; this model is based upon the observed arrangement of collagenous fibers in the annulus fibrosus. The fibers are considered to have the same mechanical properties as tendon; thus the stresses required to produce a given deformation and which irreversibly damage the fibers can be predicted. Predictions of the mechanical behavior of the disc are in good agreement with published results for compression and torsion; no comparable experiments have been performed for bending. It is further predicted that torsion and bending are likely to cause annular failure and protrusion. Failure is likely to occur posteriorly because of the effect of forward bending and because in the flattened and reentrant discs of the lumbar spine, torsional stress is concentrated at the points of maximum curvature. The structure of the disc tends to protect the collagenous fibers in forward bending and torsion. Compression is predicted to cause end-plate fracture rather than annular failure.

ISSN:0362-2436    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

Nonorganic physical signs in low-back pain are described and standardized in 350 North American and British patients. These nonorganic signs are distinguishable from the standard clinical signs of physical pathology and correlate with other psychological data. By helping to separate the physical from the nonorganic they clarify the assessment of purely physical pathologic conditions. It is suggested also that the nonorganic signs can be used as a simple clinical screen to help identify patients who require more detailed psychological assessment.

ISSN:0362-2436    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

This study reports the use of a purified form of the enzyme collagenase (Nucleolysin) to effect dissolution of the normal nucleus pulposus in a series of dogs and monkeys. A consistent dissolution effect has been observed. The toxicity of the enzyme to surrounding local tissues has been studied in the same species with an indication of safety in all areas other than intrathecal administration. A margin of safety in intrathecal administration between the effective dose and toxic dose has been suggested in the monkey. Mice LD50studies and systemic toxicity studies in dogs show a satisfactory margin of safety for this enzyme. Guinea pig studies show no significant antigenicity.

ISSN:0362-2436    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

Disorders of the lumbar spine are among the most common medical problems in western countries, affecting up to 80% of people at some time during their lives. The epidemiology and impact of six specific disorders of the lumbar spine are reviewed. These include prolapsed discs, disc degeneration, osteoarthrosis of the apophyseal joints, fractures and dislocations of vertebrae, osteoporosis, and spondylolisthesis. Various mechanical factors contribute to the causation of most of these disorders, but other underlying pathologic mechanisms are important as well. In light of the great impact of these conditions on society and on individuals, it is concluded that there is a considerable need for a greater allocation of resources for improvement in methods of prevention, diagnosis, and treatment.

ISSN:0362-2436    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

A new method of quantitative measurement with a cybex machine is applied to the trunk muscles. The curves of muscle torque and muscle fatigue are easily obtained in clinical medicine. In normal controls, maximal muscle torque is greater in back muscles than in abdominal muscles, and the definite influence of aging is found in both muscles. Furthermore, the trunk muscles are more easily fatigued by a sustained contraction than by repeated contractions, and abdominal muscles are more easily fatigued than back muscles. The role of the trunk muscles in the mechanism of pain production and prevention is still to be determined.

ISSN:0362-2436    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

The study is an investigation into the form of the abdominal pressure reflex in normal individuals under isometric loading of the torso. Various directions of load are imposed, and both flexed and upright postures are adopted. The sensitivity of the pressurization to the applied moment is calculated, the form of the response being linear in each case. The results show that the response sensitivity varies with subject posture and mass and with the direction and site of loading. The highest sensitivities are in response to extensor moments and the lowest, when the torso is flexed. It would appear that the supportive influence of the trunk cannot be considered constant under all loading conditions, nor can a single explanation of its function be adequate under both extensor and flexor applied moments.

ISSN:0362-2436    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

A model with rotational symmetry of an intervertebral disc is studied. The nucleus pulposus is assumed to consist of an incompressible fluid, and the annulus fibrosus is modeled by 11 fiber layers with alternating fiber inclination. The spaces between the fiber layers are assumed to be filled with an incompressible fluid. The pressures in the fluid compartments, the fiber strains, and the bulge are calculated under different assumptions regarding fiber inclination, fiber force–elongation relation, initial fiber layer bulges, and so on. The agreement with experimental results is very good. Possible extensions of the model are briefly discussed.

ISSN:0362-2436    

出版商:OVID    

年代:1980

数据来源: OVID