有限元法探讨犬下颌不全截骨牵张的最佳截骨量

Determination of optimum corticotomy of canine mandibular partial-cortical-cutting distraction osteogenesis by finite element anaysis

目的利用不完全截骨牵张成骨重建犬下颌节段缺失的有限元模型,控制截骨程度,探讨最佳截骨量。方法有限元模型模拟不完全截骨,在加力(12N)牵张过程中观察犬下颌皮质骨逐渐加大截骨量时截骨部位的VonMises应力,并与犬下颌骨的极限抗拉强度比较,以获得牵引时不发生断裂(骨折)的最少剩余皮质骨量。结果牵张过程中当连接处骨片剩余1mm时,滑动骨块和骨片的连接处VonMises应力是47.76MPa,最接近犬下颌骨的极限抗拉强度(约49.35MPa)。结论犬下颌行半侧不全截骨牵张成骨时,当连接骨片的剩余宽度小于1mm时,将大大增加牵张区骨折的危险性。

Objective To investigate the degree of corticotomy and find the optimum and minimum width by means of finite element model of canine mandibular partial-cortical-cutting distraction osteogenesis. Methods The finite element analysis model was established based on canine mandible and partial-cortical-cutting distraction osteogenesis simulated on the model. The Von Mises stress was observed at corticotomy site and compared with Qu of canine mandibular cortical bone （about 49. 35Mpa） during distraction osteogenesis with a force of 12 newton, when the cutting was progressed. The critical thickness of remaining bone was then decided. Results The Von Mises stress of the joint between the bone slice and the slide segment was 47.76 Mpa when the bone slide segment was retained for a thickness of 1 mm, which was most proximal to Qo （about 49.35MPa） of canine mandibular cortical bone. Conclusion The risk of fracture would increase markedly when retaining thickness of bone was less than 1 mm at the corticotomy site during canine mandibular partial-cortical-cutting distraction osteogenesis.