可吸收聚乳酸接骨板螺钉行下颌骨骨折内固定的实验研究

目的：观察国产新型L／DL－聚乳酸与DL－聚乳酸接骨装置行骨折内固定的效果并比较两种可吸收材料的性能。方法：采用自身对照研究方法，用国产新型生物降解L／DL－聚乳酸材料制作接骨板、螺钉内固定装置，对16只进行下颌骨骨折内固定，并与另一种国产生物降解DL－聚乳酸接骨板、螺钉内固定相比较。采用大体、组织学、X线摄片、骨力学测试及材料理化性能检测等方法，观察术后2、4、8、20周时的内固定效果及材料降解吸收情况。结果：所有狗双侧下颌骨骨折皆在对位良好的情况下愈合。L／DL－聚乳酸夹板固定侧骨力学强度在术后4、8周时高于DL－聚乳酸夹板固定侧聚乳酸接骨板、螺钉均能保证下颌骨骨折的愈合，符合骨折内固定的生物力学原则。L／DL－聚乳酸有较高的机械强度，更适合于向小型化发展。

Experimental study on absorbable plates and screws for internal fixation of mandibular fracture

Objective To investigate the internal fixation effects of poly ( L/DL-Lactide) and poly ( DL-Lactide ) fracture fixation devices made in China and to compare the properties of two absorbable materials. Methods Self-control design was employed. After mandibular body fracture models were performed in 16 dogs, the right sides were fixed with poly( L/DL-Lactide)plates and screws, the left with poly( DL-Lactide) plates and screws. And the comparision was made between the two kinds of fixation devices. Anatomic, histologic, radiographical and bony biomechanics examinations of the fracture site were taken immeditely after dogs were sacrificed at the 2nd, 4th, 8th and 20th week after the operation. The fixation result,degradation and absorbtion of the materials were evaluated. Results Bony union of both sides was excellent and the consolidation of fixed osteotomies seemed faster in poly ( L/DL-Lactide) group than in the poly ( DL-Lactide) group at the 4th and 8th week of the experiment (P <0. 01). The flexural strength retention of poly(L/DL Lactide) was better than that in the poly( DL-Lactide) group. It took a longer time for poly(L/DL Lactide) to be decomposed. Conclusions Poly( L/DL-Lactide) and poly( DL-Lactide) fracture fixation devices were both capable of supporting the healing of manidibular fracture and were in line with the biomechanics for internal fixation of fracture. Poly( L/ DL Lactide) had a better mechanical strength. So it was more fit for being miniatured.