牵张成骨术延长狗下颌骨的实验研究

AN EXPERIMENTAL STUDY OF MANDIBULAR LENGTHENING BY DISTRACTION OSTEOGENESIS IN CANINE MODEL

①目的 应用牵张成骨技术延长狗下颌骨动物模型 ,了解下颌骨牵张成骨过程及下颌骨牵张成骨新骨生成规律。②方法 8只成年狗 ,按不同的牵张期和固定期分为 4组 ,每组 2只。于下颌第一磨牙后区 ,行下颌骨体部骨切开术 ,安置骨支持式口腔外部牵张器。潜伏期固定 7d后牵引 ,每天延长 1mm ,分 2次进行 ,分别于第 3,10 ,2 0和 2 0天停止牵张 ,并固定。分别于牵张期开始、结束及固定期结束摄取X线片。固定期结束时处死动物 ,取牵张区新骨行组织学检查。③结果 4组动物下颌骨分别成功延长了 3,10 ,2 0和 2 0mm .X线片及组织学检查可见骨样组织、编织骨和板层骨形成、过渡及改建过程 ,并有软骨内骨化现象。④结论 下颌骨牵张成骨术其牵开区可得到良好的骨生成 ,新骨以膜内成骨为主 。

Objective\ The mandibular lengthening by traction osteogenesis was studied in canine model to understand the process of mandibular distraction osteogenesis and law of formation of new bone. \ Methods\ Eight adult dogs were divided into four groups, two for each group, based on different periods of distraction and fixation. Mandibular body corticotomies were performed, held in a neutral position for 7 days, and then lengthened at a rate of 0.5 mm per 12 hours for 3, 10, 20 and 20 days, respectively, using a unilateral external lengthening apparatus. The animals were killed on days 3, 20, 30 and 40, respectively, after completion of the fixation and traction. Results\ In the 4 groups, 3mm, 10mm, 20mm and 20mm lengthening were achieved. The results of radiographic and histological studies demonstrated that the distracted gap was filled with callus, which underwent a process of developing, transiting and remodeling of the osteoid, woven bone and lamellar bone. Endochondral ossification was also formed at the same time. \ Conclusion\ Perfect new bone formation was achieved in the area of mandibular distraction. The new bone was mainly membranous ossification, endochondral being the second.