ISSN:0362-2436    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Of all 30-, 40-, 50-, and 60-year-old inhabitants of Glostrup, a suburb of Copenhagen, 82% (449 men and 479 women) participated in a general health survey, which included a thorough physical examination relating to the lower back. The examination was constituted of anthropometric measurements, flexibility/elasticity measurements of the back and hamstrings, as well as tests for trunk muscle strength and endurance. The reproducibility of the tests was found to be satisfactory. Twelve months after the physical examination 99% of the participants completed a questionnaire sent by mall concerning low back trouble (LBT) in the intervening period. The prognostic value of the physical measurements was evaluated for first-time experience and for recurrence or persistence of LBT by analyses of the separate measurements and discriminant analyses. The main findings were that good isometric endurance of the back muscles may prevent first-time occurrence of LBT in men and that men with hypermobile backs are more liable to contract LBT. Recurrence or persistence of LBT was correlated primarily to the Interval since last LBT-episode: the more LBT, the shorter the intervals had been. Weak trunk muscles and reduced flexibility/elasticity of the back and hamstrings were found as residual signs, in particular, among those with recurrence or persistence of LBT in the follow-up year.

ISSN:0362-2436    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

It has been argued that a clarification of the mechanical causes of low-back pain requires a knowledge of the states of stress and strain throughout the lumbo-sacral spine. Since a purely experimental approach cannot provide this information, analytical model studies, to supplement measurements, are called for. In the present study, a general three-dimensional finite element program has been developed and applied for the analysis of the lumbar L2–3disc-body unit. The analysis accounts for both the material and the geometric nonlinearities and is based on a representation of the annulus as a composite of collagenous fibers embedded in a matrix of ground substance. The geometry of the model analyzed is based onin vitromeasurements. The validity of the model and the analysis procedure has been established by a comparison of those predictions that are also amenable to direct measurements, eg, the response of the disc-body unit to compressive load in terms of axial displacement, disc bulge, end-plate bulge, and intradiscal pressure. The states of stress and strain have then been computed in the cancellous bone, cortical shell, and the subchondral end-plate of the intervertebral body and in the annulus fibers and ground substance of the disc when the unit is subjected to a compressive load. The results indicate that for a normal disc with an incompressible nucleus, the most vulnerable elements under compressive load are the cancellous bone and the end-plate adjacent to the nucleus space. On the other hand, for a degenerated disc, simulated in an extreme fashion by assuming it to be void of the nucleus, the analysis predicts the annulus bulk material to be also susceptible to failure. The annulus fibers do not appear to be vulnerable to rupture when the disc-body unit is subjected to pure compressive force.

ISSN:0362-2436    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

In the adult mongrel dog,In vivoinjection of chymopapain into the intervertebral disc resulted, at two weeks, in disc space narrowing. However, [35S]sulfate labeling and proteoglycan characterization demonstrate that the nucleus retains the ability to synthesize proteoglycans, although they were degraded rapidly by residual proteolytic activity. Three months following chymopapain treatment, the intervertebral dog disc shows that an increase in disc height, return of nuclear material, and proteoglycan aggregate is present. At six months following chymopapain treatment, proteoglycans of similar characteristics to normal canine intervertebral disc are identified with a glucosamine/galactosamine ratio approaching normal values. Biomechanically, the short-term (30–120 minutes)In vitroeffects of chymopapain appear to be the same as the carrier causing increased disc height, stiffness values, and creep rates. In thein vivostudy, after three weeks, chymopapain-injected discs had significant reductions in disc height and compressive stiffness, but the creep rate was increased substantially. However, at three months postinjection, these biomechanical properties began to reverse and approached those of the uninjected controls. The observations reported in this study suggest that chymopapain has a profound but reversible effect on normal canine intervertebral disc. The radiographic narrowing of the intervertebral disc following chymopapain injection correlates with loss of proteoglycan content, structure, and biomechanical properties. The restoration of normal disc height following chymopapain injection is explained by reconstitution of normal intervertebral disc. EDTA and cysteine used alone have no discernablein vivoenzymatic effect on intervertebral disc proteoglycan biochemistry. Chemonucleolysis with chymopapain would appear less likely to alter permanently proteoglycan biochemistry and the biomechanical properties of the disc than surgical excision in experimental animals.

ISSN:0362-2436    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

The collagen content, proportion of Types I and II collagen, and the relative concentrations of the reducible crosslinks of human lumbar intervertebral discs have been found to vary with age and location and to be highly dependent on the topography of the tissue. From adolescence to mature adulthood, the most significant change is an increase in the content of Type I collagen at the expense of genetically distinct Type II collagen in the outer lamella of the posterior quadrant, while just the reverse is true of the anterior quadrant. These changes are accompanied by similar but smaller alterations in the total collagen content and in the crosslink hydroxylysinohydroxynorleucine. The same differences in the distribution of Types I and II collagens occur in the annull on the concave and convex sides of scollotic curves. Together, these data establish that active cellular activity and tissue remodelling occur in the annull fibrosl and suggest that these specific changes are initiated in response to overall increases in compressive loading on the concave side and tensile loading on the convex side of the spine and the subsequent changes they induce in the magnitude and distribution of internal stresses within the annull. In its most general formulation, the biological behavior of annull fibrosl to mechanical forces appears to follow Wolff's Law.

ISSN:0362-2436    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

The thoracolumbar fascia was studied by dissection in ten adult human cadavers. The posterior layer of this fascia was found to consist of two laminae. The superficial lamina is formed by the aponeurosis of latissimus dorsl. The deep lamina consists of bands of fibers passing caudolaterally from the midline. Both laminae form a retinaculum over the back muscles, and the deep lamina constitutes a series of accessory posterior ligaments that anchor the L2 to L5 spinous processes to the ilium and resist flexion of the lumbar spine. The function of these ligaments is enhanced by the contraction of the back muscles and the action of certain, restricted portions of the abdominal muscles.

ISSN:0362-2436    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

The purpose of this study is to Identify those individuals at risk who have weak trunk muscles and are prone to back pain. The overall thrust of this research is to develop a quantitative method to assess dynamic strength of the trunk muscles. Two unique isokinetic strength testing units in sitting and standing postures have been designed. Three groups of volunteers were tested at different times and places. Quantitative measurements of the maximum strength, fatigue behavior of the abdominal and paraspinal muscles, maximum strength in different age groups and the role of the illopsoas muscle have been performed. The study shows that women have lower maximum strength but equal or better fatigue endurance than men. There is a significant change in maximum strength with age. The maximum abdominal strength change with age showed a bimodal distribution. The illopsoas muscle approximately doubled the maximum back strength in flexion. The test in the sitting posture was tolerated better than the test in the standing posture. Isokinetic back strength testing in the sitting posture was found to be effective and safe.

ISSN:0362-2436    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Ten male and ten female subjects were tested for their ability to exert maximal force about the lumbo-sacral junction (as is done during lifting) under controlled isometric and isokinetic conditions. The myoelectric activity of ten trunk muscles, intra-abdominal pressure, and torque produced by the back were monitored. There are prominent differences in the manner in which subjects utilize the musculature of the trunk for the production of torque statically and dynamically. A significant lag was identified between the onset of intra-abdominal pressure and torque, and this lag increased with increasing trunk velocity. These differences between isometric and isokinetic exertions suggest that isokinetic trunk testing provides a means of controlled evaluation that is appropriate for manual materials handling situations.

ISSN:0362-2436    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

A new method for measuring spinal load is proposed, whereby changes in body height are used as a measure of disc compression. The rate and magnitude of disc compression are caused by the loading and its temporal pattern. A device is reported for measuring body height (SD < 1 mm). Experiments showed the dinural shrinkage during a working day and the rapid recovery when lying down. Other experiments demonstrated how the rate of shrinkage is a function of the load on the spine. Further, shrinkage when sitting in different chairs has been compared, and the results are in agreement with disc pressure measurements, reported in the literature. Finally, examples are given of how the method can be used in ergonomic evaluations.

ISSN:0362-2436    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Fifty-two patients with unilateral sciatica caused by intervertebral disc herniation were selected on strict clinical and radiological criteria. All patients had failed to respond to conservative measures. Patients in this trial group randomly were allocated surgery or Chymopapain. During the same period, a further 71 patients, who were put forward for the trial, and did not fulfill the trial criteria, were offered Chymopapain as an alternative to surgery. Both groups were assessed at one month, three months, and one year–progress being recorded by clinical examination and visual analogs. The failure rate in the two Chymopapain groups were comparable, with 52% and 47%, but were significantly higher than the surgical group (11%). Surgery in the failed Chymopapain group frequently was delayed and unrewarding. Failures can be predicted at one month posttreatment, and early surgery may be indicated to prevent chronic scarring.

ISSN:0362-2436    

出版商:OVID    

年代:1984

数据来源: OVID