Department of Mechnics, Materials and Biomedical Engineering, Wroclaw University of Science and Technology, Wroclaw, Poland.
Department of Paediatric Orthopaedics and Traumatology, Poznan University of Medical Sciences, Poznan, Poland.
J Anat. 2021 Jul;239(1):70-80. doi: 10.1111/joa.13402. Epub 2021 Jan 31.
Research in the field of spinal biomechanics, including analyses of the impact of implants on the stability of the spine, is conducted extensively in animal models. One of the basic problems in spinal implantation is the transfer and distribution of loads carried by the spine on the surfaces of the vertebral bodies. An important factor in proper cooperation of spinal implants with the vertebrae is the endplate (EP), which is why the EP in the animal model used for testing should be as similar as possible to the human EP. Therefore, this study involved multiscale structural and morphometric analyses of the animal models most commonly used in spinal biomechanics research, i.e. pig, ovine, and bovine tail. The tests were performed on 28 lumbar porcine, ovine, and bovine vertebrae. Both cranial and caudal EPs were analysed in three selected areas: anterior, middle, and posterior EPs. The conducted tests included a morphometric analysis of the trabecular bone (TB) layer of the EP as well as microscopic analysis at the mesoscale (total thickness) and microscale (thickness of the individual EP layers). The porcine EP had a characteristic increased circumferential thickness (3 mm) with a significant narrowing in the central region (50%-60%). The convex cranial ovine EP had a constant thickness throughout the cross-section and the concave caudal EP showed ~35% narrowing in the central region. The thickest EPs were observed in the bovine tail model with negligibly small narrowing in the central region (5%). The thickness of the cartilaginous layer in the porcine and bovine models reached up to 1 mm in the peripheral regions and decreased in the central part. The growth plate layer had a similar thickness in all the models. On the other hand, the narrowing of the total thickness of the EPs in the central region was mainly due to a decrease in the VEP thickness. In the ovine and bovine models, the central region of the EP was characterized by large isotropy and trabeculae of mixed or rod-like shape. By contrast, in the pig, this region had plate-like trabeculae of anisotropic nature. The porcine model was identified as best reflecting the shape and structure of the human EP and as the best surrogate model for the human EP model. This choice is particularly important in the context of biomechanical research.
脊柱生物力学领域的研究，包括对植入物对脊柱稳定性影响的分析，广泛地在动物模型中进行。脊柱植入物的一个基本问题是脊柱上的负荷在椎体表面的传递和分布。脊柱植入物与椎体适当配合的一个重要因素是终板（EP），这就是为什么用于测试的动物模型中的 EP 应该尽可能与人类 EP 相似。因此，本研究涉及对脊柱生物力学研究中最常用的动物模型，即猪、羊和牛尾，进行多尺度结构和形态计量分析。对 28 个猪、羊和牛的腰椎进行了测试。在前、中、后 EP 三个选定区域分析了颅侧和尾侧 EP。进行的测试包括 EP 小梁骨（TB）层的形态计量分析以及介观（总厚度）和微观（单个 EP 层的厚度）的显微镜分析。猪 EP 具有特征性的周向厚度增加（3 毫米），中央区域明显变窄（50%-60%）。凸形的羊颅侧 EP 在整个横截面上具有恒定的厚度，而凹形的牛尾侧 EP 在中央区域显示出约 35%的变窄。在牛尾模型中观察到最厚的 EP，中央区域的变窄可忽略不计（5%）。猪和牛模型中软骨层的厚度在周边区域可达 1 毫米，在中央部分减少。生长板层在所有模型中具有相似的厚度。另一方面，EP 中央区域总厚度的变窄主要是由于 VEP 厚度的减少。在羊和牛模型中，EP 的中央区域的特征是具有大各向同性和混合或杆状形状的小梁。相比之下，在猪中，该区域具有各向异性的板状小梁。猪模型被认为最能反映人类 EP 的形状和结构，并且是人类 EP 模型的最佳替代模型。在生物力学研究的背景下，这一选择尤为重要。
