牵张成骨术在延长下颌骨中新骨生成方式的研究

目的　探讨山羊下颌骨牵张成骨过程中新骨生成方式及其影响因素。方法　用口外牵张器 ,按1mm/天的牵张速率将 12只成年山羊的双侧下颌骨延长 10 m m,牵张结束后固定至第 2、4和 8周分别处死 4只动物 ,拍摄下颌骨 X线片后取牵张区新生骨痂作组织学观察。结果　牵张间隙内新骨组织沿牵张方向向心性生长 ,成骨方式主要是膜内成骨 ,在牵张器松动的标本早期仍可观察到散在的软骨岛。结论　牵张延长下颌骨过程中新骨生成方式主要为膜内成骨 ,软骨化骨只是在牵张器固定不良时发生。

MODE OF NEW BONE FORMATION FOLLOWING DISTRACTION OSTEOGENESIS IN MANDIBULAR LENGTHENING

Objective To investigate the mode and influential factor of new bone formation following distraction osteogenesis in mandibular lengthening. Methods Corticotomy was performed on bilateral mandibles in twelve adult male goats. A custom made distractor was used to lengthen the mandible at a rate of 1mm/day for 10 days (total 10 mm elongation). Four goats were sampled respectively at 2, 4 and 8 weeks after completion of distraction. The lengthening mandibles were examined by roentgenography and histology. Results Newly formed callus was observed in the distraction gap after mandibular lengthening. The new bone exhibited intramembranous ossification generally, but cartilage islands could be found in the specimen that diastractor loosed. Conclusion The above findings indicate that the mode of new bone formation in mandibular lengthening following distraction osteogenesis appears to be intramembranous ossification and that endochondral ossification takes place in case distractor has loosened.