下颌三焦点牵张成骨整复颏部缺损牵张区新生骨生物力学变化

Investigation of bone biomechanical properties during trifocal mandibular distraction osteogenesis

目的研究下颌三焦点牵张成骨整复颏部缺损牵张区新生骨生物力学变化。方法选取4只成年恒河猴,通过下颌前份骨截除术形成颏部正中联合骨缺损。在两侧下颌体部各制备一个输送盘,并用自行研制的多平面牵张装置使双侧输送盘向前内方向缓慢移动并在颏部正中对接以修复颏部骨缺损。牵张结束后16周处死所有动物。通过INSTRON 8874生物力学测试系统分析测定新生骨生物力学性质。结果牵张结束后16周牵张成骨区新生骨与非牵张区下颌骨体部正常骨组织相对照,抗压缩和拉伸最大应变均无明显差异。结论运用三焦点牵张成骨术整复颏部缺损牵张结束后16周牵张成骨区新生骨骨密度接近下颌骨体部正常骨组织,基本满足下颌骨功能需要。

【Objective】To study the changes of bone biomechanical properties during trifocal mandibular distraction osteogenesis.【Methods】4 monkeys were used in this study. The mandibular symphyseal defects were made by resection of the anterior part（ranged from canine to canine） of mandible. Bilateral transport disks（ranged from first premolar to first molar） were created in the remaining mandibular bodies, and a custom-made adjustable multiplanar distraction apparatus was applied to repair the artificial mandibular symphyseal defects by means of trifocal distraction osteogenesis. After a delay period of 7 days, the bilateral transport discs were distracted forward and inward simultaneously. All monkeys were sacrificed at 16 weeks after the completion of distraction. The distracted calluses and normal bone tissue in mandible body were harvested and processed. Their bone biomechanical properties were analyzed by mechanical testing. 【Results】Bone mineral density in distracted calluses showed no statistical significance compared with normal bone tissue in mandible body. 【Conclusions】This study suggested that at 16 weeks after the completion of distraction, the bone in distraction area may satisfy the function of mandible biomechanically.