不同取样方法对骨小梁结构性质分析的影响

Effects of different sampling methods on trabecular structure properties

目的为探究可比性更好、定位更精确的骨小梁取样方法提供新思路。方法从样本库中挑选20个髋关节置换术后股骨头标本,将性别相同、年龄相差不超过5岁及股骨头大小相近(直径相差<2 mm)的标本配成一对,随机分为A、B两组。A组采用标准取样方法,B组采用传统取样方法。对比两种方法取出骨柱在形态结构、轴心平均偏转角、密度值变化3方面的差异。结果传统取样组骨小梁分布不均、走行各异、小梁间延续性差且断端较多。对比标准取样组与传统取样组标本在不同旋转角度下的轴心偏转角度,前者小于后者(P=0.006)。对比骨密度参数差异,两组浅层各骨密度参数值均小于改组深层密度参数值,差异有统计学意义;小梁密度均一系数比较,标准取样组小梁均一系数大于传统取样组,骨密度(bone mineral density,BMD)(P=0.000 8)、骨体积分数(bone volumn/trabecular volumn,BV/TV)(P=0.003 4)、骨小梁厚度(trabecular thickness,Tb.Th)(P=0.000)、骨小梁数量(trabecularnumber,Tb.N)(P=0.002 9),差异有统计学意义。结论在对比分析不同个体结构、力学性能等方面的差异时,骨小梁取材部位的差异有可能造成人为偏倚,影响实验结果的准确性和真实性。

Objective To provide a novel insight in bone tissue sampling.MethodsTwenty femoral heads were extracted from sample bank of OP patients with femoral neck fracture, and they were matched with the feature of female, age gap less than 5 years and similar size of femoral head （diameter differ less than 2 mm） and were randomly assigned to two groups （A and B）. Subchondral bone columns were then extracted from these femoral heads using two different methods （A for standard method while B for conventional method）. The morphometric characterization of column specimens, the axis deflection angle and density parameters were compared between two groups.Results Trabeculae extracted in conventional way displayed a heterogeneous distribution as long as multiple lacerated ends. The axis deflection angle （ADA,α°） of conventional group was significantly greater than that of standard group （P=0.006）. The density parameters in inferior layers were significantly higher than those in superior layers in both groups. The coefficient of uniformity of standard group was significantly better than that of conventional group in bone mineral density （BMD,P=0.000 8）, bone / trabecular volumn （BT/TV,P=0.003 4）, trabecular thickness （Tb.Th,P=0.000） and trabecular number （Tb.N,P=0.002 9）.Conclusion The inconformity of the spatial position caused by conventional sampling method may affect the evaluation of trabecular microstructure changes, which should be considered as an important experimental bias that will influence the reliability of the results.