Neblett Randy, Mayer Tom G, Gatchel Robert J, Keeley Janice, Proctor Tim, Anagnostis Christopher
PRIDE Research Foundation, Dallas, TX, USA.
Spine (Phila Pa 1976). 2003 Jul 1;28(13):1435-46. doi: 10.1097/01.BRS.0000067085.46840.5A.
A two-part investigation was conducted: 1) a prospective study of asymptomatic subjects quantitatively comparing trunk mobility to surface electromyographic (sEMG) signals from the erector spinae during trunk flexion; and 2) a prospective repeated-measures cohort study of patients with chronic disabled work-related spinal disorder tested for the flexion-relaxation (FR) phenomenon while measured simultaneously for lumbar spine inclinometric range of motion (ROM).
To describe a theoretical model for the potential use of FR unloaded in assessing patients with chronic low back pain patients before and after rehabilitation, and to establish a normative database (Part 1) for subsequent use in comparison to patients with chronic low back pain (Part 2). The second part of the study assessed the clinical utility of combined sEMG and ROM measurements for assessing the FR phenomenon as a test to assist potentially in planning rehabilitation programs, guiding patients' individual rehabilitation progress, and identifying early posttreatment outcome failures.
The FR phenomenon has been recognized since 1951, and it can be reproducibly assessed in normal subjects with FR unloaded. It can be found intermittently in patients with chronic low back pain. Recent studies have moved toward deriving formulas to identify FR, but only a few have examined a potential relation between inclinometric lumbar motion measures and the sEMG signal. No previous studies have developed normative data potentially useful for objectively assessing nonoperative treatment progress, effort, or the validity of permanent impairment rating measures.
In Part 1, 12 asymptomatic subjects were evaluated in an intra- and interrater repeated-measures protocol to examine reliability of sEMG signal readings in FR, as well as ROM measures at FR and maximum voluntary flexion. The mean sEMG signal averaging right-left electrode recordings, as well as the gross, true, and sacral lumbar ROM measurements, were recorded as normative data. In Part 2, 54 patients with chronic disabled work-related spinal disorder referred as candidates for tertiary functional restoration rehabilitation participated in a standardized assessment protocol for sEMG and ROM measurement before rehabilitation. Those who completed the program were retested with the identical methodology after rehabilitation (n = 34) using the empirically derived cutoff scores for sEMG readings at FR and ROM from Part 1 and prior scientific literature. Pain disability self-reported scores were correlated with sEMG and ROM. Sensitivity and specificity of the sEMG for identifying abnormal motion were assessed.
In Part 1, the ability of the experienced testers to measure ROM and sEMG reliably at FR was high (r >or= 0.92; P < 0.001). All asymptomatic subjects achieved FR at a tightly clustered range of mean sEMG signals from 1 to 2.3 microV. Most of the variation between motion at FR and maximum voluntary flexion occurred through the hip (sacral) motion component of the gross (or total) motion measured at T12. In Part 2, posttreatment reliability for ROM, sEMG, and the ability to detect the FR point was high (r >or= 0.82; P < 0.001). More than 30% of the 54 patients tested before treatment demonstrated ability to achieve FR, with FR usually associated with higher ROM than in the non-FR patients. After treatment, 94% of those who completed the program achieved FR, including all those who achieved FR before treatment. Flexion-relaxation was associated with major improvement in ROM and pain disability self-report.
Flexion-relaxation measures a point at which true lumbar flexion ROM approaches its maximum in asymptomatic subjects. This also is the point at which lumbar extensor muscle contraction relaxes, allowing the lumbar spine to hang on its posterior ligaments. The gluteal and hamstring muscles then lower the flexed trunk even further by allowing the pelvis to rotate around the hips. This phenomenon was subsequently found in Part 2 to offer a potentially promising method for individualizing rehabilitation treatment, decreasing unnecessary utilization, identifying potential postrehabilitation treatment failures, and assessing permanent impairment rating validity. Moreover, this is the first study to demonstrate systematically that an absence of FR in patients with chronic low back pain can be corrected with treatment.
进行了两部分调查：1）对无症状受试者进行前瞻性研究，定量比较躯干屈曲过程中躯干活动度与竖脊肌表面肌电图（sEMG）信号；2）对患有慢性致残性工作相关脊柱疾病的患者进行前瞻性重复测量队列研究，测试其屈伸放松（FR）现象，同时测量腰椎倾斜度活动范围（ROM）。
描述一种理论模型，用于潜在地利用无负荷FR评估慢性下腰痛患者康复前后的情况，并建立一个规范数据库（第1部分），以供后续与慢性下腰痛患者（第2部分）进行比较。研究的第二部分评估了联合sEMG和ROM测量对评估FR现象的临床效用，作为一种测试，可能有助于规划康复计划、指导患者的个体康复进展以及识别治疗后早期结果失败情况。
FR现象自1951年以来已被认识到，并且可以在无负荷FR的正常受试者中进行可重复评估。在慢性下腰痛患者中可间歇性发现该现象。最近的研究已朝着推导识别FR的公式发展，但只有少数研究检查了倾斜度腰椎运动测量与sEMG信号之间的潜在关系。以前没有研究建立过可能有助于客观评估非手术治疗进展、效果或永久性损伤评级措施有效性的规范数据。
在第1部分中，对12名无症状受试者按照评估者内和评估者间重复测量方案进行评估，以检查FR中sEMG信号读数的可靠性，以及FR和最大自主屈曲时的ROM测量。记录左右电极记录的平均sEMG信号平均值，以及总体、真实和骶腰ROM测量值作为规范数据。在第2部分中，54名被转诊为三级功能恢复康复候选者的慢性致残性工作相关脊柱疾病患者在康复前参加了sEMG和ROM测量的标准化评估方案。完成该计划的患者在康复后（n = 34）使用从第1部分和先前科学文献中根据经验得出的FR时sEMG读数和ROM的临界值分数，采用相同方法进行重新测试。疼痛残疾自我报告分数与sEMG和ROM相关。评估sEMG识别异常运动的敏感性和特异性。
在第1部分中，经验丰富的测试者在FR时可靠测量ROM和sEMG的能力很高（r≥0.92；P<0.001）。所有无症状受试者在平均sEMG信号紧密聚集在1至2.3微伏的范围内实现了FR。FR和最大自主屈曲之间的运动差异大多通过在T12测量的总体（或总）运动的髋部（骶部）运动分量产生。在第2部分中，ROM、sEMG的治疗后可靠性以及检测FR点的能力很高（r≥0.82；P<0.001）。在治疗前测试的54名患者中，超过30%表现出实现FR的能力，FR通常与比非FR患者更高的ROM相关。治疗后，完成该计划的患者中有94%实现了FR，包括所有治疗前实现FR的患者。屈伸放松与ROM和疼痛残疾自我报告的显著改善相关。
屈伸放松测量的是无症状受试者中真正的腰椎屈曲ROM接近其最大值的点。这也是腰椎伸肌收缩放松的点，使腰椎依靠其后部韧带悬挂。然后臀肌和腘绳肌通过允许骨盆围绕髋关节旋转，使屈曲的躯干进一步降低。随后在第2部分中发现，这种现象为个性化康复治疗、减少不必要的利用、识别潜在的康复后治疗失败以及评估永久性损伤评级有效性提供了一种潜在的有前景的方法。此外，这是第一项系统证明慢性下腰痛患者中FR缺失可通过治疗纠正的研究。
