Adams M A, Dolan P, Hutton W C, Porter R W
Comparative Orthopaedic Research Unit, University of Bristol, England.
J Bone Joint Surg Br. 1990 Mar;72(2):266-70. doi: 10.1302/0301-620X.72B2.2138156.
Diurnal changes in the loads acting on the spine affect the water content and height of the intervertebral discs. We have reviewed the effects of these changes on spinal mechanics, and their possible clinical significance. Cadaveric lumbar spines subjected to periods of creep loading show a disc height change similar to the physiological change. As a result intervertebral discs bulge more, become stiffer in compression and more flexible in bending. Disc tissue becomes more elastic as its water content falls, and its affinity for water increases. Disc prolapse becomes more difficult. The neural arch and associated ligaments resist an increasing proportion of the compressive and bending stresses acting on the spine. Observations on living people show that these changes are not fully compensated for by modified muscle activity. We conclude that different spinal structures are more heavily loaded at different times of the day. Therefore, the time of onset of symptoms and signs, and any diurnal variation in their severity, may help us understand more about the pathophysiology of low back pain and sciatica.
作用于脊柱的负荷的昼夜变化会影响椎间盘的含水量和高度。我们回顾了这些变化对脊柱力学的影响及其可能的临床意义。经历蠕变加载期的尸体腰椎显示出与生理变化相似的椎间盘高度变化。结果，椎间盘膨出更多，受压时变得更硬，弯曲时更灵活。随着椎间盘组织含水量下降，其弹性增加，对水的亲和力增强。椎间盘突出变得更加困难。神经弓及相关韧带承受着作用于脊柱的越来越大比例的压缩和弯曲应力。对活人进行的观察表明，这些变化并未通过改变的肌肉活动得到充分补偿。我们得出结论，不同的脊柱结构在一天中的不同时间承受的负荷更大。因此，症状和体征出现的时间以及其严重程度的任何昼夜变化，可能有助于我们更多地了解腰痛和坐骨神经痛的病理生理学。
