冷冻、冻干、辐照对用于脊柱融合的胫骨皮质骨力学性能的影响

目的研究冷冻、冻干及辐照处理方法对胫骨皮质骨抗压强度和硬度的影响,探讨适合的胫骨皮质骨处理方法。方法收取外伤截肢的胫骨干中段皮质骨,将其加工成大小约10 mm×10 mm×5 mm的皮质骨板,并随机平均分为7组:正常组(A组)、深冻组(B组)、冻干组(C组)、冷冻+~(60)Co辐照(25 J/g)组(D组)、冷冻+~(60)Co辐照(50 J/g)组(E组)、冻干+~(60)Co辐照(25 J/g)(F组)、冻干+~(60)Co辐照(50 J/g)组(G组)。应用生物材料试验机分别对不同处理方法的同种皮质骨进行抗压强度和硬度测试。结果胫骨皮质骨的最大抗压强度为6.089~9.089 k N。与A组比较,B、C、D、F组胫骨皮质骨的抗压强度无明显区别(P0.05),B、C组硬度无明显区别(P0.05),但D、F组硬度分别减少9.6%(P0.05)和8.7%(P0.05);E、G组与A组比较,抗压强度分别减少29.6%(P0.05)和33.1%(P0.05),硬度分别减少16.7%(P0.05)和14.8%(P0.05)。结论对胫骨皮质骨进行冷冻、冻干处理时,抗压强度及硬度较无处理组无明显变化。与无处理组比较,冷冻后或冻干后接受小剂量60Co辐照时胫骨皮质骨的抗压强度无明显变化,但硬度有一定降低;大剂量60Co辐照时,抗压强度及硬度均有明显降低。在应用同种皮质骨融合支架行椎间融合时,辐照灭菌剂量应控制在15~25 J/g。

Effects from deep-freezing, freeze-drying or radiation on mechanical properties of cortical bone for spinal fusion

Objective To study the effects on compressive strength and rigidity of tibia cortical bone from deep-freezing, freeze-drying or radiation treatments, and to discuss the appropriate method for tibia cortical bone treatment. Methods The cortical bone were collected from the middle part in tibial diaphysis from amputated limbs of trauma patients and made into bone plates with the size of 10 mm×10 mm×5 mm each. The bone plates were then divided into seven groups evenly and randomly: control group (Group A), deep-freezing group (Group B), freeze-drying group(Group C), deep-freezing plus 60Co (25 J/g) radiation group(Group D), deep-freezing plus 60Co (50 J/g) radiation group(Group E), freeze-drying plus 60Co (25 J/g) radiation group(Group F), freeze-drying plus 60Co (50 J/g) radiation group(Group G). The compressive strength and rigidity of allograft cortical bone were tested by mechanical testing machine. Results The largest compressive strength of the tibia cortical bone was in the range of 6.089-9.089 kN. Compared with Group A, the strength in Group B, C, D and F showed no significant difference, and the rigidity in Group B and C showed no significant difference, while the rigidity in Group D and F was decreased by 9.6% (P<0.05) and 8.7% (P<0.05), respectively. Compared with Group A, the strength in Group E and G was reduced by 29.6% (P<0.05) and 33.1% (P<0.05), respectively, and the rigidity was reduced by 16.7% (P<0.05) and 14.8% (P<0.05), respectively. Conclusions The strength and rigidity of tibia cortical bone are not changed significantly after deep-freezing or freeze-drying treatment. Compared with the untreated group, the strength of tibial cortical bone with the small dosage of 60Co treatment is not significantly changed after deep-freezing or freeze-drying, but the rigidity is decreased; the strength and rigidity with the large dosage of 60Co treatment are decreased obviously. For application of cortical bone used in spinal fusion, radiation sterilization dosage should be controlled in the range of 15-25 J/g.