下颌体缺损腓骨重建小型钛板固定的生物力学分析

目的：分析小型钛板固定下颌体缺损腓骨重建的应力分布特点及位移情况,为下颌体缺损腓骨重建的内固定提供生物力学参考。方法：建立下颌体缺损腓骨重建小型4孔钛板固定的有限元模型,模拟前牙与健侧磨牙垂直加载,分析钛板钛钉应力分布及腓骨前后端位移情况。结果：前牙加载时,相应钛板钛钉应力、腓骨前后端位移值均大于后牙加载时;前牙加载时腓骨前端最大位移值为264.44 μm,而后牙加载时为149.02 μm。钛板最大应力值出现在后上方钛板处;下颌骨残端钛钉最大应力值位于前上方靠近交界处的第1颗钛钉处,应力沿钉尖方向逐渐减小,在钉尖1/3处应力出现增大现象。结论：在下颌体缺损腓骨重建小钛板固定时,选择双皮质钛钉十分必要;在骨愈合前应避免前牙咬合,减少骨不愈合的风险。

Biomechanical analysis of mandibular body defect reconstruction with fibula fixed with miniplates

PURPOSE： To investigate the stress distribution characteristics and displacement of mandibular body defect reconstruction with fibula fixed with miniplates and to provide mechanical reference for clinical practice. METHODS： Finite element model of mandibular body defect reconstruction with fibula fixed with miniplates was established and eontralateral molar and incisor vertical loading was simulated. Then stress of plates, screws and displacement of anterior and posterior ends of the fibula were analysed. RESULTS： Stress of corresponding miniplates, screws and displacement values of anterior and posterior fibula in incisor loading condition were larger than that of in molar loading condition. Maximum displacement value of anterior fibula in incisor loading condition was 264.22 microns, while 149.02 microns in molar loading conditions. Maximum stress values of all miniplates occurred in the posterior plate. Maximum stress of screws in the mandibular stumps occurred in the anterior superior screw near the mandible /fibula adjunction. Stress of screws began to decrease along the direction of nail tip, but stress in the one third tip of screw increased. CONCLUSIONS： It is very important to choose bieortical screw when mandibular body defect reconstruction with fibula in fixations. Biting on front teeth before bone healing to reduce the risk of nonunion should be avoided. Supported by Science and Technology Project of Guangdong Province （2012B0313800144） and New Technology and New Project of Nanfang Hospital （201118 ）.