Vaillant Michèle, Pickar Joel G, Kawchuk Gregory N
Graduate Student, University of Alberta, Edmonton, Alberta, Canada.
J Manipulative Physiol Ther. 2010 Oct;33(8):585-93. doi: 10.1016/j.jmpt.2010.08.020.
Spinal manipulation therapy (SMT), an intervention used to treat low back pain, has been demonstrated to affect the stiffness of the spine. To adequately quantify the effects of SMT on stiffness, a device capable of applying specific parameters of manipulation in addition to measuring force-displacement values has been developed previously. Previously developed indentation techniques that quantify stiffness have been modified for novel use in evaluating SMT parameters. The reliability of stiffness measurements performed by the newly adapted device was assessed in this study.
Seven springs of varying stiffness were each indented 10 times by a variable rate force/displacement (VRFD) device. Indentations were performed at a rate of 0.5 mm/s to a maximal displacement of 4 mm. The stiffness coefficients for a middle portion of the resulting force-displacement graph and the terminal instantaneous stiffness (stiffness at end displacement) were calculated. The intraclass correlation and confidence interval were calculated for these stiffness measurements to assess device reliability.
Repeated spring stiffness measures yielded an intraclass correlation coefficient value of 1.0. The mean stiffness values had narrow 95% confidence intervals ranging from 0.01 N/mm to 0.06 N/mm and small coefficients of variation.
This VRFD device provides highly reliable stiffness measurements in controlled conditions. Although in vivo reliability remains to be established, the results of this study support the use of the VRFD device in future trials investigating the impact of various SMT parameters on spinal stiffness.
脊柱推拿疗法（SMT）是一种用于治疗腰痛的干预措施，已被证明会影响脊柱的刚度。为了充分量化SMT对刚度的影响，先前已开发出一种除了测量力-位移值之外还能够施加特定推拿参数的装置。先前开发的用于量化刚度的压痕技术已被修改，用于评估SMT参数的新用途。本研究评估了新改装装置进行的刚度测量的可靠性。
使用可变速率力/位移（VRFD）装置对七个不同刚度的弹簧各进行10次压痕。压痕以0.5 mm/s的速率进行，最大位移为4 mm。计算所得力-位移图中间部分的刚度系数和末端瞬时刚度（末端位移时的刚度）。计算这些刚度测量值的组内相关性和置信区间，以评估装置的可靠性。
重复的弹簧刚度测量得出组内相关系数值为1.0。平均刚度值的95%置信区间较窄，范围从0.01 N/mm到0.06 N/mm，变异系数较小。
该VRFD装置在受控条件下提供高度可靠的刚度测量。尽管体内可靠性仍有待确定，但本研究结果支持在未来试验中使用VRFD装置来研究各种SMT参数对脊柱刚度的影响。
