Division of Biokinesiology and Physical Therapy, University of Southern California, 1540 E. Alcazar St, CHP-155, Los Angeles, CA 90089, USA; Spine Biomechanics and Tissue Engineering Laboratory, Cedars-Sinai Medical Center, 8700 Beverly Blvd., Davis Building, 6006, Los Angeles, CA 90048, USA.
Spine J. 2013 Nov;13(11):1581-9. doi: 10.1016/j.spinee.2013.04.011. Epub 2013 May 21.
Intervertebral disc and facet joints are the two primary load-bearing structures of the lumbar spine, and altered loading to these structures may be associated with frontal plane spinal deviations.
To determine the load on the lumbar facet joint and intervertebral disc under simulated frontal plane pelvic obliquity combined loading, an in vitro biomechanical study was conducted.
STUDY DESIGN/SETTING: An in vitro biomechanical study using a repeated-measures design was used to compare L4-L5 facet joint and intervertebral disc loading across pure moment and combined loading conditions.
Eight fresh-frozen lumbosacral specimens were tested under five loading conditions: flexion/extension, lateral bending, axial rotation using pure moment bending (±10 Nm), and two additional tests investigating frontal plane pelvic obliquity and axial rotation (sacrum tilted left 5° and at 10° followed by a ±10-Nm rotation moment). Three-dimensional kinematics, facet load, and intradiscal pressures were recorded from the L4-L5 functional spinal unit.
Sagittal and frontal plane loading resulted in significantly smaller facet joint forces compared with conditions implementing a rotation moment (p<.05). The facet joint had the highest peak load during the 10° combined loading condition (124.0±30.2 N) and the lowest peak load in flexion (26.8±16.1 N). Intradiscal pressure was high in lateral flexion (495.6±280.9 kPa) and flexion (429.0±212.9 kPa), whereas intradiscal pressures measured in rotation (253.2±135.0 kPa) and 5° and 10° combined loading conditions were low (255.5±132.7 and 267.1±127.1 kPa, respectively).
Facet loading increased during simulated pelvic obliquity in frontal and transverse planes, whereas intradiscal pressures were decreased compared with sagittal and frontal plane motions alone. Altered spinopelvic alignment may increase the loads experienced by spinal tissue, especially the facet joints.
椎间盘和小关节是腰椎的两个主要承重结构，这些结构的负荷改变可能与额状面脊柱偏曲有关。
为了确定模拟额状面骨盆倾斜复合加载下腰椎小关节和椎间盘的负荷，进行了一项体外生物力学研究。
研究设计/设置：采用重复测量设计的体外生物力学研究比较了纯力矩和复合加载条件下 L4-L5 小关节和椎间盘的加载情况。
对 8 个新鲜冷冻的腰骶标本进行了 5 种加载条件下的测试：屈伸、侧屈、轴向旋转（±10 Nm），以及另外两项研究额状面骨盆倾斜和轴向旋转的测试（骶骨向左倾斜 5°和 10°，然后施加±10-Nm 的旋转力矩）。从 L4-L5 功能脊柱单元记录三维运动学、小关节负荷和椎间盘内压。
与实施旋转力矩的条件相比，矢状面和额状面加载导致小关节力显著减小（p<.05）。小关节在 10°复合加载条件下的峰值负荷最高（124.0±30.2 N），在屈伸时的峰值负荷最低（26.8±16.1 N）。在侧屈（495.6±280.9 kPa）和屈伸（429.0±212.9 kPa）时椎间盘内压较高，而在旋转（253.2±135.0 kPa）和 5°和 10°复合加载条件下的椎间盘内压较低（分别为 255.5±132.7 和 267.1±127.1 kPa）。
在模拟额状面骨盆倾斜的情况下，小关节的负荷增加，而与矢状面和额状面运动相比，椎间盘内压降低。脊柱骨盆对线的改变可能会增加脊柱组织，特别是小关节的负荷。
