Department of Biomedical Engineering, University of Akron, Akron, OH 44325, USA.
Spine (Phila Pa 1976). 2012 Sep 15;37(20):E1238-42. doi: 10.1097/BRS.0b013e31826111a3.
An in vitro biomechanical study on 3-dimensional flexibility of human lumbosacral motion segments after multiple freeze-thaw cycles and cumulative testing.
To determine the significance of multiple freeze-thaw cycles and extended testing duration on between-day and within-day variations in motion segment flexibility.
Previous studies have found no significant effect of single freeze-thaw cycle on creep behavior of human spinal motion segments. Up to 3 freeze-thaw cycles were found to not affect flexibility of porcine spines and viscoelastic properties of human tendons, but more than 5 freeze-thaw cycles resulted in declined structural properties of human tendons.
Three lumbosacral motion segments were subjected to repeated flexibility tests to determine both the effects of within-day ambient exposure and between-day multiple freeze-thaw cycles on range of motion (ROM) and neutral zone (NZ). Repeated measures analysis of variance was carried out to evaluate within-day and between-day effects at α = .05.
Significant between-day effects were found for intervertebral ROM and NZ in flexion-extension (FE), lateral bending (LB), and axial rotation (AR) (all P < 0.001). Post hoc analysis indicated that significant differences from test day 1 become apparent after 4 freeze-thaw cycles with cumulative testing. There were no within-day variations from repeated testing on intervertebral FE ROM (P = 0.10), LB ROM (P = 0.36), AR ROM (P = 0.46), FE NZ (P = 0.83), LB NZ (P = 0.42), and AR NZ (P = 0.72).
The flexibility of the human cadaveric lumbosacral motion segments between test days was significantly affected after repeated freeze-thaw and cumulative testing cycles. Multiple freeze-thaw cycles and cumulative testing, however, does not affect flexibility data for tests carried out within a single test day.
多次冻融循环和累积测试后人类腰骶运动节段三维灵活性的体外生物力学研究。
确定多次冻融循环和延长测试时间对运动节段灵活性日内和日间变化的意义。
先前的研究发现单次冻融循环对人类脊柱运动节段的蠕变行为没有显著影响。多达 3 次冻融循环不会影响猪脊柱的灵活性和人类肌腱的粘弹性，但超过 5 次冻融循环会导致人类肌腱的结构特性下降。
对三个腰骶运动节段进行重复的柔韧性测试，以确定日内环境暴露和日间多次冻融循环对活动范围（ROM）和中立区（NZ）的影响。采用重复测量方差分析，在 α =.05 水平评估日内和日间效应。
在屈伸（FE）、侧屈（LB）和轴向旋转（AR）中，发现椎间 ROM 和 NZ 存在显著的日间效应（均 P < 0.001）。事后分析表明，在累积测试后进行 4 次冻融循环后，与第 1 天测试相比，差异明显。在重复测试中，椎间 FE ROM（P = 0.10）、LB ROM（P = 0.36）、AR ROM（P = 0.46）、FE NZ（P = 0.83）、LB NZ（P = 0.42）和 AR NZ（P = 0.72）无日内变化。
在多次冻融和累积测试循环后，人类尸体腰骶运动节段的柔韧性在测试日之间受到显著影响。然而，多次冻融循环和累积测试不会影响单日进行的测试的柔韧性数据。
