Spine
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A review of the literature on disc nutrition. ⋯ Loss of nutrient supply can lead to cell death, loss of matrix production, and increase in matrix degradation and hence to disc degeneration.
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A review of the literature on macromechanical factors that accelerate disc degeneration with particular focus on distinguishing the roles of immobilization and overloading. ⋯ It is concluded that probably any abnormal loading conditions (including overload and immobilization) can produce tissue trauma and/or adaptive changes that may result in disc degeneration. Adverse mechanical conditions can be due to external forces, or may result from impaired neuromuscular control of the paraspinal and abdominal muscles. Future studies will need to evaluate additional unquantified interactions between biomechanics and factors such as genetics and behavioral responses to pain and disability.
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Review of the most recent advances in the development of poro-elastic analytical models that include physiologic parameters used for understanding lumbar disc degeneration due to repetitive loading. ⋯ A number of different approaches have been used to address the issue of disc degeneration. Poro-elastic finite element model including strain-dependent permeability and osmotic pressure is the most popular analytical tool currently available that can be used to understand how cyclic loading affects the biomechanical characteristics of a degenerated lumbar disc. However, it is important to note that a complete understanding of the behavior of the intervertebral disc will ultimately be arrived using a combination of analytical models, such as the models presented here, in addition to in vitro and in vivo experimental methods.