Department of Orthopaedics, Balgrist University Hospital, Zurich, Switzerland.
Institute for Biomechanics, ETH Zurich, Zurich, Switzerland.
Spine (Phila Pa 1976). 2021 Aug 15;46(16):E869-E877. doi: 10.1097/BRS.0000000000003883.
Biomechanical cadaveric study.
The aim of this study was to evaluate the effect of degeneration on biomechanical properties of the passive structures of the lumbar spine.
Although the load apportionment among the passive structures in healthy spines follows well-defined contribution patterns, it remains unknown how this load distribution and sagittal preload changes by degenerative processes of the intervertebral disc (IVD).
Fifty lumbar spinal segments were tested in a displacement-controlled stepwise reduction study in flexion, extension, axial rotation, lateral bending, anterior, posterior and lateral shear. The intertransverse ligaments (ITLs), supraspinous and interspinous ligaments (ISL&SSL), facet joint capsules (FJC), facet joints (FJ), ligamentum flavum (LF), posterior longitudinal ligament (PLL), anterior longitudinal ligament (ALL), and spondylophytes were subsequently reduced. The results were set in relation to IVD-degeneration, quantified with Pfirrmann classification.
In flexion, a load redistribution from LF (-28% n.s.) and PLL (-13% n.s.) towards the IVD (+9%, n.s.) is observed comparing grade 2 to 5 IVD degeneration, whereas in all other loading directions, a reduction of IVD-contribution from -12% to -53% is recorded. In axial rotation, anterior and lateral shear, more load is shared by the FJ (+4% n.s., +23% ∗, +13% n.s.). The preload of the ALL, LF, PLL, and IVD is reduced ranging from -0.06 Nm to -0.37 Nm.
IVD degeneration is related to notable load-redistributions between the passive spinal structures. With further degeneration, reduced contribution of the LF and PLL and higher loads on the IVD are observed in flexion. In the other tested loading directions, the relative load on the IVD is reduced, whereas higher FJ-exposure in axial rotation, anterior and lateral shear is observed. Furthermore, the preload of the spinal structures is reduced. These observations can further the understanding of the degenerative cascade in the spine.Level of Evidence: N/A.
生物力学尸体研究。
本研究旨在评估腰椎被动结构退变对生物力学特性的影响。
尽管健康脊柱中被动结构的载荷分配遵循明确的贡献模式，但仍不清楚这种载荷分布和矢状预加载如何因椎间盘（IVD）的退行性过程而改变。
在弯曲、伸展、轴向旋转、侧屈、前屈、后伸和侧方剪切的分步减压研究中，对 50 个腰椎节段进行了测试。椎间横韧带（ITL）、棘上和棘间韧带（ISL 和 SSL）、关节突关节囊（FJC）、关节突关节（FJ）、黄韧带（LF）、后纵韧带（PLL）、前纵韧带（ALL）和脊椎骨赘随后被切除。结果与 IVD 退变相关，通过 Pfirrmann 分级进行量化。
在弯曲时，与 II 级到 V 级 IVD 退变相比，LF（-28%n.s.）和 PLL（-13%n.s.）的负荷向 IVD（+9%n.s.）重新分配，而在所有其他加载方向，记录到 IVD 贡献的减少从-12%到-53%。在轴向旋转、前屈和侧方剪切时，FJ（+4%n.s.、+23%∗、+13%n.s.）的负荷分担增加。ALL、LF、PLL 和 IVD 的预载减少了 0.06 至 0.37 Nm。
IVD 退变与被动脊柱结构之间的显著负荷重新分布有关。随着进一步的退变，在弯曲时，LF 和 PLL 的贡献减少，IVD 的负荷增加。在其他测试的加载方向，IVD 的相对负荷减少，而轴向旋转、前屈和侧方剪切时 FJ 的暴露增加。此外，脊柱结构的预载减少。这些观察结果可以进一步了解脊柱的退行性级联反应。
N/A。
