Arendt-Nielsen Lars, Graven-Nielsen Thomas, Svarrer Heine, Svensson Peter
Laboratory for Experimental Pain Research, Aalborg University, Aalborg Denmark Department of Rheumatology, Aalborg Hospital, Aalborg Denmark Department of Prosthetic and Stomatognathic Physiology, Royal Dental College, University of Aarhus, Aarhus Denmark.
Pain. 1996 Feb;64(2):231-240. doi: 10.1016/0304-3959(95)00115-8.
Chronic low back pain (CLBP) is a major clinical problem with a substantial socio-economical impact. Today, diagnosis and therapy are insufficient, and knowledge concerning interaction between musculoskeletal pain and motor performance is lacking. Most studies in this field have been performed under static conditions which may not represent CLBP patients' daily-life routines. A standardized way to study the sensory-motor interaction under controlled motor performances is to induce experimental muscle pain by i.m. injection of hypertonic saline. The aim of the present controlled study was to analyze and compare electromyographic (EMG) activity of and coordination between lumbar muscles (8 paraspinal recordings) during gait in 10 patients with CLBP and in 10 volunteers exposed to experimental back muscle pain induced by bolus injection of 5% hypertonic saline. When the results are compared to sex- and age-matched controls, the CLBP patients showed significantly increased EMG activity in the swing phase; a phase where the lumbar muscles are normally silent. These changes correlated significantly to the intensity of the back pain. Similar EMG patterns were found in the experimental study together with a reduced peak EMG activity in the period during double stance where the back muscles are normally active. Generally, these changes were localized ipsilaterally to the site of pain induction. The clinical and experimental findings indicate that musculoskeletal pain modulates motor performance during gait probably via reflex pathways. Initially, these EMG changes may be interpreted as a functional adaptation to muscle pain, but the consequences of chronic altered muscle performance are not known. New possibilities to monitor and investigate altered motor performance may help to develop more rational therapies for CLBP patients.
慢性下腰痛（CLBP）是一个重大的临床问题，具有巨大的社会经济影响。如今，诊断和治疗方法尚不完善，且缺乏关于肌肉骨骼疼痛与运动表现之间相互作用的知识。该领域的大多数研究都是在静态条件下进行的，这可能无法代表CLBP患者的日常生活。一种在可控运动表现下研究感觉运动相互作用的标准化方法是通过肌肉注射高渗盐水诱导实验性肌肉疼痛。本对照研究的目的是分析和比较10例CLBP患者和10例接受5%高渗盐水推注诱导实验性背部肌肉疼痛的志愿者在步态过程中腰椎肌肉（8个椎旁记录）的肌电图（EMG）活动及协调性。当将结果与性别和年龄匹配的对照组进行比较时，CLBP患者在摆动期的EMG活动显著增加；而在这个阶段，腰椎肌肉通常是不活动的。这些变化与背痛的强度显著相关。在实验研究中发现了类似的EMG模式，并且在双支撑期（此时背部肌肉通常是活跃的），EMG活动峰值降低。一般来说，这些变化定位于疼痛诱导部位的同侧。临床和实验结果表明，肌肉骨骼疼痛可能通过反射途径调节步态中的运动表现。最初，这些EMG变化可能被解释为对肌肉疼痛的功能适应，但慢性改变的肌肉表现所带来的后果尚不清楚。监测和研究运动表现改变的新方法可能有助于为CLBP患者开发更合理的治疗方法。
