European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society
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Comparative Study
Biomechanical evaluation of the New Zealand white rabbit lumbar spine: a physiologic characterization.
Physiologic motions of the human, sheep, and calf lumbar spines have been well characterized. The size, cost, and ease of care all make the rabbit an attractive alternative choice for an animal lumbar spine model. However, comparisons of normal biomechanical characteristics of the rabbit lumbar spine have not been made to the spines of larger species. ⋯ This relatively conserved physiologic flexibility supports the use of the rabbit as a model of the lumbar spine for kinematic studies. However, the overall NZ was found to be a greater percentage of ROM in the rabbit than the corresponding percentage in the human (60% as compared to 25%). This suggested that the rabbit lumbar spine has a greater laxity than that of the human.
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Comparative Study
The relationship of disability (Oswestry) and pain drawings to functional testing.
There was much enthusiasm about the development of computerized dynamometry in providing large quantities of data to objectively assess muscle performance. However, a much more basic issue arose questioning what these machines actual measure, particularly in pain populations. The purpose of the present study was to determine whether patients' self-reported disability and pain expression, as evaluated with simple questionnaires, were related to isokinetic performance in low back pain patients. ⋯ The results of this study indicate that isokinetic test values are significantly influenced by a patient's self-reported disability and pain expression, which can be evaluated using simple tools such as pain drawings and the Oswestry questionnaire. This study supports the supposition that dynamometry testing is related to factors other than muscle performance.
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Comparative Study
A method to evaluate the in vivo behaviour of lumbar spine implants.
The aim of the study was to design a method for evaluating the stabilizing effect of different lumbar spine implants in vivo, and to apply this method to a comparison of plates versus rods in lumbar spine posterolateral fusion using transpedicular screw fixation. Fourteen patients, seven operated on with transpedicular plates and screws (VSP), and seven operated on with rods and screws (Diapason), matched according to number of levels fused, had tantalum markers inserted in the vertebrae at surgery, enabling roentgen stereophotogrammetric analysis (RSA). Mean patient age was 45 (range 33-56) years. ⋯ One patient stabilized with rods and screws between L5 and S1 displayed a sagittal translation of 1.01 mm but no mobility along the transverse or vertical axes. In the remaining 13 patients, positional change from supine to standing did not provoke any intervertebral mobility above the RSA accuracy along any of the axes. With the limited provocation described, in line with the postoperative regimen for lumbar fusion patients, plates with transpedicular screws and rods with transpedicular screws both seem to give adequate intervertebral stability in posterolateral lumbar fusions.
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The goal of this study was to evaluate the ability of Ray threaded fusion cages, when used in an anterior approach, to restore intervertebral height and to improve the functional and occupational performance of the patients. The present study was initiated because insertion of fusion cages through a posterior approach causes destruction of facet joints and violation of the spinal canal. The anterior approach for insertion of threaded fusion cages to accomplish lumbar interbody fusion was evaluated in a series of 13 patients suffering monosegmental disc disease. ⋯ Although for the non-revised patients, the mean Prolo scores remained relatively stable during the 1st year, they dropped after 3 years. We were not able to identify any further clinical or radiological differences between the groups. These results indicate that although the anterior approach seems technically suitable for insertion of threaded fusion cages, destruction of the anterior longitudinal ligament and the anterior part of the annulus fibrosis appears to result in destabilisation of the motion segment.
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The precise dimensions of the lumbar vertebrae and discs are critical for the production of appropriate spinal implants. Unfortunately, existing databases of vertebral and intervertebral dimensions are limited either in accuracy, study population or parameters recorded. The objective of this study is to provide a large and accurate database of lumbar spinal characteristics from 126 digitised computed tomographic (CT) images, reviewed using the Picture Archiving Communication System (PACS) coupled with its internal measuring instrumentation. ⋯ A comprehensive database of vertebral and intervertebral dimensions was generated from 378 lumbar vertebrae from 126 patients measured with a precise digital technique. These results are invaluable in establishing an anthropometric model of the human lumbar spine, and provide useful data for anatomical research. In addition this is important information for the scientific planning of spinal surgery and for the design of spinal implants.