不同孔径骨修复材料消旋聚乳酸对骨再生的影响

目的：探讨不同孔径三维多孔骨修复材料DL－PLA植入兔桡骨骨缺损区对骨长入的影响，方法：将采用浇注盐析技术制成的孔隙率为75％而孔径不同的三维多孔DL－PLA材料植入兔桡骨骨缺损区，并设立空白对照组，分别在术后2，4，8，12周行X线检查，取材做大体观察，组织形态学检查，生物力学检测，结果：植入材料孔径为约250，400，750μm者均有大量新生骨组织形成，而植入孔径约为75μm者及空白对照组12周时民损区两端骨髓腔已闭合，植入250μm者8和12周时抗弯强度最高（P＜0．01），结论：三维多孔材料孔径大小对骨长入起决定性作用，孔径为约250um的材料最有利于骨长入。

Effect of pore size of D, L-polylactic acid as bone repair material on bone regeneration.

OBJECTIVE: To study the bone regeneration behavior in porous D,L-polylactic acid (D,L-PLA) with different pore sizes. METHOD: A particulate-leaching method was employed to prepare porous biodegradable D,L-PLA with different pore sizes (75, 250, 400, 750 micrometer) and with porosity of 75% as the materials to repair bone defects in rabbits. The materials were then implanted at random into 40 rabbits with bilateral radius bone defect, leaving another 10 rabbits without implantation as blank control. Gross observation and X-ray and histomorphological examination as well as assessment of the biomechanics of the implants were performed in 2, 4, 8 and 12 weeks respectively after the operation. RESULTS: New bone tissue occurred around the implanted materials with pore sizes of 250, 400 or 750 micrometer 12 weeks after the operation. In the control group and in the rabbits with implants with pore size of 75 micrometer, the bone defect was filled with connective tissues. The implants with 250-micrometer pores had the strongest biomechanical strengths of all the materials (P<0.01) at 8 weeks and 12 weeks after the operation. CONCLUSION: The pore size of the porous implants decides the behavior of bone regeneration, and D, L-PLA polymer with 250-micrometer pores produces the most desired effects.