VERTEBRAL POSITION ALTERS MUSCLE SPINDLE SENSITIVITY

描述（由申请人提供）：特发性腰痛和脊柱按摩的治疗用途在临床、社会和经济上产生了重大影响。据估计，我们中超过75%的人在一生中的某个时候会经历腰痛，每年的费用估计为200亿至500亿美元。最近的荟萃分析结果表明，脊柱推拿可以推荐临床治疗急性和慢性特发性腰痛。脊椎按摩师提供了超过90%的脊柱操作在美国和脊椎按摩服务的年度支出超过47亿美元。特发性腰痛的原因和脊柱推拿的生理作用机制都还不清楚。申请人最近的研究表明，椎骨的力学历史改变了腰椎椎旁肌梭对随后椎骨运动的敏感性。响应于椎骨滑动（平移）的肌梭放电取决于椎骨先前是否保持在卸载或加载梭的位置，时间短至5秒。我们相信脊柱中的这一新发现很重要，因为运动节段不断受到被动力的影响，这些被动力可以固定它们的空间方向。所提出的实验基于3个假设。 (1)椎旁肌梭对椎体平移的敏感性增加时，椎体的线性位移先前卸载椎旁肌梭。 (2)椎旁肌梭对椎体平移的敏感性降低时，椎体的线性位移先前加载椎旁肌梭。 (3)脊柱推拿的治疗效果可能是介导的，在某种程度上，其纠正椎旁肌梭敏感性的位置历史依赖性变化的能力。椎旁肌梭感觉反馈的历史依赖性改变可能导致本体感受错误，并对节段运动的神经控制产生不利影响。了解影响脊椎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组成部分有关。

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.