Experimental Tissue Mechanics Laboratory, Department of Chemical and Materials Engineering, University of Auckland, Auckland, New Zealand.
Department of Orthopaedic Surgery, Auckland City Hospital, Auckland, New Zealand.
Spine (Phila Pa 1976). 2017 Nov 1;42(21):1604-1613. doi: 10.1097/BRS.0000000000002181.
Structural investigation of mechanically induced herniations in ovine lumbar motion segments.
This new study addresses the question of whether there are regions other than the posterior and posterolateral aspects that are implicated in the initiation of disc disruption and herniation.
Flexion in combination with compressive loading will induce disc herniations in healthy motion segments in vitro. Although it is widely accepted that the posterior and posterolateral regions of the disc are the primary sites of herniation much less is known as to whether other regions of the disc might be involved in the herniation process.
Healthy ovine lumbar motion segments (n = 14) were flexed 10° and compressed at a rate of 40 mm/min up to point of failure. The discs were macroscopically analyzed using progressive transverse sectioning to obtain a more global picture of internal disc disruption and herniation.
A high prevalence of disruption in the lateral annulus was found associated with circumferential tracking of nucleus between the annular layers toward the posterolateral and posterior regions. In all tests this lateral disruption did not cause any discernible external change in the lateral disc periphery after the removal of load. After imposing the predetermined flexion the applied compression also induced a forward anterior shear of the superior vertebra of approximately equal magnitude to the axial compressive displacement.
The vulnerability of the lateral annulus to disruption is thought to arise from the overloading of its differentially recruited oblique/counteroblique fiber sets, this in turn generated by anterior shear developed in the flexed, compressed motion segment. This lateral annular disruption, followed by circumferential tracking of nuclear material and resulting in either contained or uncontained extrusions in the posterior or posterolateral annulus, highlights the complexity of the herniation process.
N/A.
机械诱导羊腰椎运动节段疝出的结构研究。
本研究旨在探讨除后外侧区域以外，是否还有其他区域参与椎间盘破裂和疝出的启动。
体外研究表明，在健康的运动节段中，屈伸结合压缩负荷会导致椎间盘突出。虽然广泛认为椎间盘的后外侧区域是疝出的主要部位，但对于椎间盘的其他区域是否可能参与疝出过程，人们知之甚少。
对 14 个健康的羊腰椎运动节段进行 10°的屈伸和 40mm/min 的压缩，直至达到失效点。使用逐步横断切片法对椎间盘进行宏观分析，以获得椎间盘内部破裂和疝出的更全面的图像。
发现外侧环有很高的破裂发生率，与核在环层之间向外侧和后侧的环状跟踪有关。在所有测试中，在去除负荷后，这种外侧破裂并没有导致外侧椎间盘边缘出现任何明显的外部变化。在施加预定的屈曲后，施加的压缩也会导致上关节突向前前剪切，其幅度与轴向压缩位移大致相等。
认为外侧环易破裂是由于其不同募集的斜向/对斜向纤维束的过载，而这种纤维束的过载是由屈曲、压缩运动节段中产生的前剪切引起的。这种外侧环的破裂，随后是核物质的环状跟踪，导致后外侧环出现包含或不包含的挤出，突出了疝出过程的复杂性。
无。
