Dalle Carbonare L, Giannini S
Department of Medical and Surgical Sciences, Medical Clinic I, University of Padova, Padova, Italy.
J Endocrinol Invest. 2004 Jan;27(1):99-105. doi: 10.1007/BF03350919.
Structure and microarchitecture are determinant aspects of bone strength and essential elements for the assessment of bone mechanical properties. The main structural determinants of bone mechanical strength include width and porosity in the cortical bone; shape, width, connectivity, and anisotropy in the trabecular bone. There are several methods to assess bone architecture, particularly at the trabecular level. Two different approaches can be identified. The first is based on the use of optical microscopy and on the principles of quantitative histology, which evaluate microarchitecture two-dimensionally. The second applies the most modern diagnostic techniques, employing computed tomography and magnetic resonance to obtain and analyze three-dimensional images. From a clinical point of view, microarchitecture is an interesting aspect to study and define specific patterns, such as glucocorticoid-induced osteoporosis, or to evaluate bone alterations in transplanted patients. Microarchitecture seems to be a determinant of bone fragility independent of bone density. Moreover, bone microarchitecture seems to be important to understand the mechanisms of bone fragility as well as the action of the drugs used to prevent osteoporotic fractures. Several in vivo studies (on animals and humans) showed important findings on the effects of different treatments on microarchitecture. Bisphosphonates and parathyroid hormone seemed to preserve or even improve microarchitecture. These observations can provide an additional interpretation for the anti-fracture effect of drugs from a structural viewpoint. The challenge for the future will be to evaluate bone quality in vivo with the same or better resolution and accuracy than the invasive methods in use today.
结构和微观结构是骨强度的决定性方面，也是评估骨力学性能的关键要素。骨力学强度的主要结构决定因素包括皮质骨的宽度和孔隙率；小梁骨的形状、宽度、连通性和各向异性。有多种方法可用于评估骨结构，尤其是在小梁水平。可以确定两种不同的方法。第一种基于光学显微镜的使用和定量组织学原理，二维评估微观结构。第二种应用最现代的诊断技术，利用计算机断层扫描和磁共振来获取和分析三维图像。从临床角度来看，微观结构是一个有趣的研究方面，可用于定义特定模式，如糖皮质激素诱导的骨质疏松症，或评估移植患者的骨改变。微观结构似乎是独立于骨密度的骨脆性决定因素。此外，骨微观结构对于理解骨脆性机制以及用于预防骨质疏松性骨折的药物作用似乎也很重要。多项体内研究（对动物和人类）显示了不同治疗对微观结构影响的重要发现。双膦酸盐和甲状旁腺激素似乎能保留甚至改善微观结构。这些观察结果可以从结构角度为药物的抗骨折作用提供额外的解释。未来的挑战将是在体内以与当今使用的侵入性方法相同或更高的分辨率和准确性来评估骨质量。
