Wong Arnold Y L, Parent Eric C, Prasad Narasimha, Huang Christopher, Chan K Ming, Kawchuk Gregory N
Department of Physical Therapy, University of Alberta, Edmonton, Alberta, Canada.
Department of Physical Therapy, University of Alberta, Edmonton, Alberta, Canada.
Clin Biomech (Bristol). 2016 May;34:45-52. doi: 10.1016/j.clinbiomech.2016.03.006. Epub 2016 Mar 31.
While some patients with low back pain demonstrate increased spinal stiffness that decreases as pain subsides, this observation is inconsistent. Currently, the relation between spinal stiffness and low back pain remains unclear. This study aimed to investigate the effects of experimental low back pain on temporal changes in posteroanterior spinal stiffness and concurrent trunk muscle activity.
In separate sessions five days apart, nine asymptomatic participants received equal volume injections of hypertonic or isotonic saline in random order into the L3-L5 interspinous ligaments. Pain intensity, spinal stiffness (global and terminal stiffness) at the L3 level, and the surface electromyographic activity of six trunk muscles were measured before, immediately after, and 25-minute after injections. These outcome measures under different saline conditions were compared by generalized estimating equations.
Compared to isotonic saline injections, hypertonic saline injections evoked significantly higher pain intensity (mean difference: 5.7/10), higher global (mean difference: 0.73N/mm) and terminal stiffness (mean difference: 0.58N/mm), and increased activity of four trunk muscles during indentation (P<0.05). Both spinal stiffness and trunk muscle activity returned to baseline levels as pain subsided.
While previous clinical research reported inconsistent findings regarding the association between spinal stiffness and low back pain, our study revealed that experimental pain caused temporary increases in spinal stiffness and concurrent trunk muscle co-contraction during indentation, which helps explain the temporal relation between spinal stiffness and low back pain observed in some clinical studies. Our results substantiate the role of spinal stiffness assessments in monitoring back pain progression.
虽然一些腰痛患者表现出脊柱僵硬增加，且随着疼痛缓解而降低，但这一观察结果并不一致。目前，脊柱僵硬与腰痛之间的关系仍不清楚。本研究旨在探讨实验性腰痛对脊柱后前向僵硬的时间变化以及同时发生的躯干肌肉活动的影响。
在相隔五天的不同时间段，九名无症状参与者以随机顺序在L3-L5棘间韧带接受等体积的高渗或等渗盐水注射。在注射前、注射后即刻以及注射后25分钟测量疼痛强度、L3水平的脊柱僵硬（整体和终末僵硬）以及六块躯干肌肉的表面肌电图活动。通过广义估计方程比较不同盐水条件下的这些结果指标。
与等渗盐水注射相比，高渗盐水注射引起明显更高的疼痛强度（平均差异：5.7/10）、更高的整体僵硬（平均差异：0.73N/mm）和终末僵硬（平均差异：0.58N/mm），并且在压痕过程中四块躯干肌肉的活动增加（P<0.05）。随着疼痛缓解，脊柱僵硬和躯干肌肉活动均恢复到基线水平。
虽然先前的临床研究报告了关于脊柱僵硬与腰痛之间关联的不一致结果，但我们的研究表明，实验性疼痛导致脊柱僵硬暂时增加以及在压痕过程中同时发生躯干肌肉共同收缩，这有助于解释在一些临床研究中观察到的脊柱僵硬与腰痛之间的时间关系。我们的结果证实了脊柱僵硬评估在监测背痛进展中的作用。
