VERTEBRAL POSITION ALTERS MUSCLE SPINDLE SENSITIVITY

描述（由申请人提供）：特发性腰痛和脊柱操作的治疗使用在临床，社会和经济上产生重大影响。据估计，超过75%的人在一生中的某个时候会经历腰痛，每年造成的损失估计在200亿到500亿美元之间。最近的荟萃分析结果表明，脊柱推拿可推荐用于临床治疗急性和慢性特发性腰痛。在美国，90%以上的脊椎推拿都是由脊椎按摩师完成的，每年用于脊椎按摩服务的支出超过47亿美元。特发性腰痛的原因和脊柱操作的生理作用机制都没有得到很好的理解。申请人最近的调查表明，椎体的机械史改变了腰椎棘旁肌纺锤体对随后椎体运动的敏感性。肌肉主轴放电对椎体滑动（平移）的反应取决于椎体之前是否保持在卸载或加载纺锤体的位置仅5秒钟。我们相信这个在脊柱上的新发现是重要的，因为运动节段不断受到被动力的影响，可以固定它们的空间方向。提出的实验是基于3个假设。(1)当椎体的线性位移已使棘旁肌纺锤体卸除负荷时，棘旁肌纺锤体对椎体平移的敏感性增加。(2)当椎体的线性位移已经对棘旁肌纺锤体造成负荷时，棘旁肌纺锤体对椎体平移的敏感性降低。(3)脊柱操纵的治疗效果可能部分是通过其纠正脊柱旁肌纺锤体敏感性的位置历史依赖性变化的能力来调节的。椎旁肌纺锤体感觉反馈的历史依赖性改变可能导致本体感觉错误，并对节段性运动的神经控制产生不利影响。了解影响椎体组织感觉输入的机械因素将有助于更好地了解脊柱护理的最适当的预防和治疗干预措施。脊柱推拿本质上是一种生物力学干预，脊柱推拿治疗特发性腰痛的成功可能部分与特发性腰痛的机械成分有关。

DESCRIPTION (provided by applicant): Idiopathic low back pain and the therapeutic use of spinal manipulation make a significant impact clinically, socially, and financially. It has been estimated that more than 75 percent of us will experience low-back pain at some time in our lives costing an estimated $20-$50 billion annually. Recent findings from meta-analyses indicate that spinal manipulation can be recommended clinically for the treatment of acute and chronic idiopathic low back pain. Chiropractors deliver more than 90 percent of spinal manipulations performed in the United and annual expenditures on chiropractic services exceed $4.7 billion annually. Neither the causes of idiopathic low back pain nor the mechanisms underlying the physiological effects of spinal manipulation are well understood. Recent investigations by the applicant indicate that the mechanical history of a vertebra alters the sensitivity of lumbar paraspinal muscle spindles to subsequent vertebral movement. Muscle spindle discharge in response to vertebral gliding (translation) depended upon whether the vertebra had been previously held in a position that unloaded or loaded the spindle for as little as 5 seconds. We believe this novel finding in the spine is important because motion segments are continually subjected to passive forces that can fix their spatial orientation. The proposed experiments are based upon 3 hypotheses. (1) Sensitivity of paraspinal muscle spindles to vertebral translation increases when linear displacement of the vertebra has previously unloaded the paraspinal muscle spindle. (2) Sensitivity of paraspinal muscle spindles to vertebral translation decreases when linear displacement of the vertebra has previously loaded the paraspinal muscle spindle. (3) The therapeutic effects of spinal manipulation may be mediated, in part, by its ability to correct the positional-history-dependent changes in paraspinal muscle spindle sensitivity. History-dependent alterations in sensory feedback from paraspinal muscle spindles could lead to proprioceptive errors and adversely affect neural control of segmental motion. Knowledge of mechanical factors that affect sensory input from vertebral tissues will help provide a better understanding of the most appropriate preventive and therapeutic interventions for spinal care. Spinal manipulation is inherently a biomechanical intervention and the therapeutic successes of spinal manipulation for idiopathic low back pain may relate, in part, to the mechanical component of idiopathic low back.