Time varying modulators of spine injury mechanics and material properties of the intervertebral disc

世界卫生组织认为下腰痛是三大职业健康问题之一。80%的加拿大人会在一生中的某个时候遭受下腰痛的折磨，这使得下腰痛成为影响加拿大总人口的最普遍、最昂贵的肌肉骨骼问题。有证据表明，下腰痛的主要原因是与日常活动和工业任务有关的机械暴露。虽然涉及举重的任务通常与下腰痛有关，但似乎久坐不动的任务，如长时间站立或坐着，也与下腰痛有关。坐和站是工作场所常见的活动，由于自动化和越来越多的计算机使用，花在这些姿势上的时间正在增加。这项研究计划的总体目标是评估每日负荷暴露在腰背组织损伤和疼痛产生中的作用。将调查由于慢性暴露而导致脊柱结构(如椎间盘)损伤开始和发展的原因。检查个人在执行久坐任务时对腰部的需求的研究将与组织水平的调查相结合，以评估脊柱组织的随时间变化的反应和由此产生的损伤潜力。对与机械负荷相关的损伤机制的深入了解对于损伤预防至关重要，因为由于缺乏对该结构的血液供应，椎间盘中的生物修复机制是缓慢的。一旦椎间盘损伤的第一阶段发生，脊髓组织自我修复的能力很容易被损伤恶化所超过。这项研究的结果将提供与时间相关的组织材料特性，这些特性目前无法获得，并且是理解和模拟椎间和腰部损伤的限制因素。最终，将累积或慢性暴露与潜在疼痛产生联系起来，将是开发评估每日负荷和设定阈值限制或暴露标准以防止伤害的方法的强大和新颖的贡献。

The World Health Organization has deemed low back pain one of the top three occupational health problems. Eighty percent of the population will suffer from low back pain at some point in their life making low back pain the most prevalent and costly musculoskeletal problem affecting the general population of Canada. Evidence suggests that the primary cause of low back pain is through mechanical exposure associated with everyday activities and industrial tasks. While tasks involving heavy lifting are often linked with low back pain, seemingly sedentary tasks such as prolonged standing or sitting have also been associated with low back pain. Sitting and standing are common activities in the workplace and the time spent in these postures is increasing due to automation and increasing computer usage. The overall objective of this research program is to assess the role of daily loading exposures in the generation of low back tissue damage and pain. The causes of injury initiation and progression in the structures of the spine (e.g. the intervertebral disc) due to chronic exposure will be investigated. Studies examining the demands on the low back of individuals when performing sedentary tasks will be combined with investigations at the tissue level to assess time-dependent responses of spinal tissues and the resulting injury potential. A solid understanding of the injury mechanisms associated with mechanical loading is critical for injury prevention, as the biological repair mechanisms in the intervertebral disc are slow due to the lack of blood supply to this structure. The ability of the spinal tissues to repair themselves can easily be outpaced by injury deterioration once the first stage of an injury to the intervertebral disc has occurred. The outcomes from this research will provide time dependent tissue material properties that are currently unavailable and are a limiting factor in the understanding and modeling of intervertebral and low back injuries. Ultimately, the linking of cumulative or chronic exposure with potential pain generation would be a powerful and novel contribution in developing methods to assess daily loading and set threshold limits or exposure standards to prevent injuries.