Zehra Uruj, Robson-Brown Kate, Adams Michael A, Dolan Patricia
*Centre for Comparative and Clinical Anatomy and †School of Archaeology and Anthropology, University of Bristol, Bristol, United Kingdom.
Spine (Phila Pa 1976). 2015 Aug 1;40(15):1173-80. doi: 10.1097/BRS.0000000000000925.
Mechanical and microcomputed tomography (micro-CT) study of cadaver spines.
To compare porosity and thickness of vertebral endplates with (1) compressive stresses measured in adjacent intervertebral discs and (2) grade of disc degeneration.
Endplate porosity is important for disc metabolite transport, and yet porosity increases with age and disc degeneration. We hypothesize that porosity is largely determined by mechanical loading from adjacent discs.
Forty motion segments (T8-9 to L4-5) were dissected from 23 cadavers aged 48 to 98 years. Each was subjected to 1 kN compression during which time intradiscal stresses were measured by pulling a pressure transducer along the disc's midsagittal diameter. "Stress profiles" revealed the average pressure in the nucleus, and the maximum stress in the anterior and posterior annulus. Specimens were further dissected to obtain discs with endplates (and 5 mm of bone) on either side. Microcomputed tomography scans (resolution 35 μm) were analyzed to calculate thickness and porosity in the midsagittal regions of all 80 endplates. Average values for the anterior, central, and posterior regions of each endplate were obtained. Disc degeneration was assessed macroscopically and microscopically.
Endplate porosity was inversely related to its thickness, being greatest in the central region opposite the nucleus, and least near the periphery. Superior endplates (relative to the disc) were 14% thicker (P < 0.001) and 4% less porous (P = 0.008) than inferior. In each of the 3 endplate regions (anterior, central, and posterior), porosity was inversely and significantly related to mechanical loading (pressure or maximum stress) in the adjacent disc region (P < 0.01 in all cases). Disc degeneration was best predicted by (reduced) nucleus pressure (R = 0.46, P < 0.001) and (reduced) maximum stress in the anterior annulus (R = 0.31, P < 0.001).
Mechanical loading is a major determinant of endplate thickness and porosity. Disc degeneration is more closely related to reduced disc stresses than to endplate thickness or porosity.
N/A.
尸体脊柱的力学和微型计算机断层扫描（micro-CT）研究。
比较椎体终板的孔隙率和厚度与（1）相邻椎间盘测量的压缩应力以及（2）椎间盘退变程度。
终板孔隙率对椎间盘代谢物运输很重要，然而孔隙率会随着年龄和椎间盘退变而增加。我们假设孔隙率在很大程度上由相邻椎间盘的机械负荷决定。
从23具年龄在48至98岁的尸体上解剖出40个运动节段（T8-9至L4-5）。每个运动节段承受1 kN的压缩力，在此期间通过沿着椎间盘的矢状径拉动压力传感器来测量椎间盘内应力。“应力分布”显示了髓核中的平均压力以及前、后纤维环中的最大应力。进一步解剖标本以获取两侧带有终板（和5毫米骨质）的椎间盘。对微型计算机断层扫描（分辨率35μm）进行分析，以计算所有80个终板矢状区域的厚度和孔隙率。获得每个终板前、中、后区域的平均值。通过宏观和微观评估椎间盘退变情况。
终板孔隙率与其厚度呈负相关，在与髓核相对的中央区域最大，在周边附近最小。相对于椎间盘，上终板厚14%（P < 0.001），孔隙率低4%（P = 0.008）。在终板的3个区域（前、中、后）中，每个区域的孔隙率与相邻椎间盘区域的机械负荷（压力或最大应力）呈负相关且显著相关（所有情况下P < 0.01）。椎间盘退变最好由（降低的）髓核压力（R = 0.46，P < 0.001）和前纤维环中的（降低）最大应力（R = 0.31，P < 0.001）预测。
机械负荷是终板厚度和孔隙率的主要决定因素。椎间盘退变与椎间盘应力降低的关系比与终板厚度或孔隙率的关系更密切。
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