Nanaimo, British Columbia, Canada.
Spine J. 2010 Apr;10(4):297-305. doi: 10.1016/j.spinee.2010.01.009. Epub 2010 Feb 26.
Sitting is associated with loss of the lumbar lordosis, intervertebral disc (IVD) compression, and height loss, possibly increasing the risk of lower back pain. With a trend toward more sitting jobs worldwide, practical strategies for preventing lumbar flattening and potentially associated low back pain (LBP) are important.
The purpose of this study was to determine the feasibility of using upright magnetic resonance imaging (MRI) and stadiometry to measure changes in height and configuration of the lumbar spine before and after normal sitting and a seated unloading exercise intervention.
STUDY DESIGN/SETTING: This is a hospital-based pilot study involving pre-post assessments in a single group.
The sample comprises six asymptomatic hospital employees involved in either general patient care or research writing/data collection.
The outcome measures were lumbar total midsagittal cross-sectional IVD area, vertical height, lordotic angle derived from digitized MRI examinations, and seated body height measured directly with a stadiometer.
Midsagittal MRI scans were performed before sitting, after 15 minutes of relaxed sitting ("postsitting"), immediately after seated unloading exercises, and approximately 7 minutes after exercise. Subsequently, seated stadiometry assessments were performed after 10 minutes of supine recumbency, 15 minutes of relaxed sitting, and every 10 seconds after seated unloading exercises until three consecutive height measurements were identical. Digitized midsagittal images were used to derive MRI-based outcome measures. Measurements at postsitting were compared with the corresponding ones at other time points using multiple paired t-tests. The Bonferroni method was used to adjust for multiple pairwise comparisons.
After 15 minutes of sitting, mean total IVD area, lordotic angle, and vertical height of the lumbar spine decreased 18.6 mm(2), 6.2 degrees , and 12.5 mm, respectively, whereas after seated unloading exercises, these parameters increased by 87.9 mm(2), 5.0 degrees , and 21.9 mm, respectively. Similarly, mean seated height on stadiometry decreased by 6.9 mm after 15 minutes of sitting and subsequently increased by 5.7 mm after unloading exercises.
Seated upright MRI and stadiometry, as performed in this study, appear to be feasible methods for detecting compressive and decompressive spinal changes associated with normal sitting and, alternately, seated unloading exercises. Larger studies are encouraged to determine normative values of our study measurements and to determine if morphological changes induced by seated unloading predict treatment response and/or reductions in the incidence of sitting-related LBP.
坐姿会导致腰椎前凸减小、椎间盘（IVD）受压和高度降低，从而可能增加腰痛的风险。随着全球坐姿工作趋势的增加，预防腰椎变平及潜在相关腰痛（LBP）的实用策略非常重要。
本研究旨在确定使用直立磁共振成像（MRI）和测高仪测量正常坐姿和坐姿卸载运动干预前后腰椎高度和形态变化的可行性。
研究设计/设置：这是一项基于医院的试点研究，涉及单个组的前后评估。
样本包括六名无症状的医院员工，他们从事一般患者护理或研究写作/数据收集。
结果测量包括腰椎总矢状面 IVD 面积、垂直高度、数字化 MRI 检查得出的前凸角以及使用测高仪直接测量的坐姿身体高度。
在坐姿前、坐姿 15 分钟后（“post-sitting”）、立即进行坐姿卸载运动后以及运动后约 7 分钟进行 MRI 矢状扫描。随后，在仰卧位休息 10 分钟、放松坐姿 15 分钟后以及坐姿卸载运动后每 10 秒进行一次坐姿测高，直到三次连续测量高度相同。使用数字化矢状图像得出基于 MRI 的结果测量值。使用多个配对 t 检验比较 post-sitting 时的测量值与其他时间点的测量值。使用 Bonferroni 方法对多次配对比较进行调整。
坐姿 15 分钟后，腰椎 IVD 总面积、前凸角和垂直高度分别减少 18.6mm²、6.2 度和 12.5mm，而进行坐姿卸载运动后，这些参数分别增加 87.9mm²、5.0 度和 21.9mm。同样，坐姿测高仪上的平均坐姿高度在坐姿 15 分钟后下降 6.9mm，随后在卸载运动后增加 5.7mm。
本研究中进行的坐姿直立 MRI 和测高术似乎是检测与正常坐姿和交替坐姿卸载运动相关的压缩和减压脊柱变化的可行方法。鼓励进行更大规模的研究以确定我们研究测量值的正常值，并确定坐姿卸载引起的形态变化是否预测治疗反应和/或降低与坐姿相关的 LBP 发生率。
