青年与老年尸体肋骨冲击力学特性的比较

Comparison of rib impact mechanical properties from youth and elderly corpses

背景:骨质疏松、骨重建、骨再造、胸椎骨折固定器选择等都需要了解青年和老年尸体肋骨的冲击力学特性。以往的研究多以单独青年尸体或单独老年尸体肋骨为观察对象,而有关青年和老年尸体肋骨冲击力学特性的研究报道极少。目的:对正常国人青年和老年新鲜尸体肋骨进行冲击实验,分析肋骨的冲击力学性质,确定老年尸体肋骨和青年尸体肋骨是否具有不同的冲击力学性质。方法:实验标本取自4具正常国人男性新鲜尸体,年龄分别为20,25,70,75岁,由吉林大学医学部解剖教研室提供。人死亡后1h内解剖取出死者肋骨T3～12标本,将标本沿纵向切成长55mm的试样,青年组和老年组各20个。以能量释放的方法对2组试样进行冲击实验。实验结束后,试验机测量度盘自动显示试样的冲击功,根据材料力学公式计算出每个试样的冲击韧性,观察各试样的宏观断口形貌。结果与结论:青年组肋骨冲击功、冲击韧性均显著大于老年组(P<0.05)。肋骨冲击实验断口多数为粉碎性断口,少数为横断口或斜断口。肉眼观察发现青年组肋骨骨小梁排列细密,老年组肋骨骨小梁排列稀疏,孔隙较大,呈现出老年骨质疏松的表现形式。提示青年组肋骨和老年组肋骨具有不同的冲击力学特性,老年组试样由于骨质疏松导致冲击力学特性发生改变。

BACKGROUND： Impact mechanics properties of ribs should be understood in treating osteoporosis, bone remodeling, bone reconstruction, as well as artificial joint replacement. Most of previous studies concerning youth and the elderly bodies alone, reports regarding impact of ribs mechanical properties are few. OBJECTIVE： To perform impact experiment to the normal people youth and the elderly fresh corpse ribs to survey the impact mechanical properties, and to definite whether the impact mechanical properties of ribs have difference between youth and the elderly people. METHODS： Experimental samples were from 4 normal fresh corpse, aged 20, 25, 70 and 75 years, were provided by Department of Anatomy, Norman Bethune Medical University. Spinal column ribs T3-12 specimen were obtained from corpse within 1 hours and cut into 55-mm long pieces, with 20 test pieces in each group. The impact experiment was performed using energy liberation method at room temperature under 20 ℃. After experiment, the impact energy was displayed automatic on testing machine, and the impact toughness was calculated by mechanical formula, and the morphology of fracture surface was observed. RESULTS AND CONCLUSION： The impact energy and impact toughness of the youth group was obviously greater than that of the elderly group （P〈0.05）. Majority of the fracture surfaces were comminuted, minority were transverse or oblique fracture. The macroscopic observation showed that trabecular arranged compact in the ribs of the youth group, which was sparse arrangement and presented with senile osteoporosis in the elderly group. It demonstrated that the impact mechanics properties of ribs are different between the youth and elderly groups, and osteoporosis changes impact mechanics properties in the elderly people.