Background

The spinal meninges play a mechanical protective role for the spinal cord. Better knowledge of the mechanical behavior of these tissues wrapping the cord is required to accurately model the stress and strain fields of the spinal cord during physiological or traumatic motions. Then, the mechanical properties of meninges along the spinal canal are not well documented. The aim of this study was to quantify the elastic meningeal mechanical properties along the porcine spinal cord in both the longitudinal direction and in the circumferential directions for the dura-arachnoid maters complex (DAC) and solely in the longitudinal direction for the pia mater. This analysis was completed in providing a range of isotropic hyperelastic coefficients to take into account the toe region.

Methods

Six complete spines (C0 – L5) were harvested from pigs (2–3 months) weighing 43±13 kg. The mechanical tests were performed within 12 h post mortem. A preload of 0.5 N was applied to the pia mater and of 2 N to the DAC samples, followed by 30 preconditioning cycles. Specimens were then loaded to failure at the same strain rate 0.2 mm/s (approximately 0.02/s, traction velocity/length of the sample) up to 12 mm of displacement.

Results

The following mean values were proposed for the elastic moduli of the spinal meninges. Longitudinal DAC elastic moduli: 22.4 MPa in cervical, 38.1 MPa in thoracic and 36.6 MPa in lumbar spinal levels; circumferential DAC elastic moduli: 20.6 MPa in cervical, 21.2 MPa in thoracic and 12.2 MPa in lumbar spinal levels; and longitudinal pia mater elastic moduli: 18.4 MPa in cervical, 17.2 MPa in thoracic and 19.6 MPa in lumbar spinal levels.

Discussion

The variety of mechanical properties of the spinal meninges suggests that it cannot be regarded as a homogenous structure along the whole length of the spinal cord.

中文翻译：

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颈，胸和腰猪脊髓脊膜的拉伸力学性能

背景

脊膜对脊髓具有机械保护作用。需要更好地了解这些包裹脐带的组织的机械行为，以在生理或创伤运动中准确地模拟脊髓的应力和应变场。然后，沿椎管的脑膜的机械性能没有得到很好的证明。这项研究的目的是量化硬脑膜-蛛网膜复合物（DAC）在纵向和圆周方向上沿猪脊髓的弹性脑膜力学性能，而在软脑膜上仅量化在纵向上。通过提供一系列各向同性的超弹性系数来完成此分析，以考虑脚趾区域。

方法

从体重43±13 kg的猪（2-3个月）中收获了六个完整的棘（C0-L5）。验尸后12小时内进行机械测试。将0.5 N的预载荷施加到微积分器上，将2 N的预载荷施加到DAC样本上，然后进行30个预处理循环。然后以相同的应变速率0.2 mm / s（约0.02 / s，牵引速度/样品长度）将试样加载至破坏，直至位移达到12 mm。

结果

提出以下平均值作为脊膜的弹性模量。纵向DAC弹性模量：颈椎为22.4 MPa，胸椎为38.1 MPa，腰椎为36.6 MPa；圆周DAC弹性模量：颈椎为20.6 MPa，胸椎为21.2 MPa，腰椎为12.2 MPa；颈椎纵向弹性模量：颈椎为18.4 MPa，胸椎为17.2 MPa，腰椎为19.6 MPa。

讨论区

脊膜的各种机械性能表明，不能将其视为沿脊髓全长的同质结构。