下颌三焦点牵张成骨过程中血供重建的实验研究

目的观察下颌三焦点牵张成骨过程中血管生成和血供重建的立体形态构筑。方法选取4只实验用成年恒河猴,均行下颌前份骨截除,形成颏部正中联合骨缺损后,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正中对接,以修复颏部骨缺损。分别在牵张开始及牵张结束的第0、2、4周选取1只实验恒河猴进行影像学检查,并采用树脂灌注微血管铸型技术,酸蚀后用扫描电镜观察血管的立体形态构筑。结果影像学检查(摄X线片):牵张结束时,两侧输送盘被牵张器引导向前,并向中线移动,输送盘远心端在正中成功对接,颏部弓形缺损被整复。随固定时间延长,两侧牵张间隙骨小梁不断成熟完善,直至牵张结束后第4周,下颌骨连续性完全恢复。树脂灌注微血管铸型后扫描电镜观察:牵张开始,牵张间隙及颏部正中联合区骨膜血管普遍增生、膨胀,呈现大量血管新生的征象;骨髓内的微静脉和静脉窦也开始膨大。在牵张结束第0周,骨膜血管及骨髓内的微静脉和静脉窦增生活跃,大量骨膜来源的微血管分支长入牵张间隙及颏部正中联合区。在牵张间隙,来源于骨膜和骨髓的新生血管形成血管网,新生成的血管网平行于牵张方向相互连接并包裹整个牵张间隙;而在颏部正中联合区,血管网的排列较为无序。在牵张结束第2周,牵张间隙中央区仍可见血管增生征象,在牵张区与两侧输送盘在下颌中线的血管连接广泛。固定第4周,血管新生现象逐渐消失,再生骨段的血管系统己基本恢复正常。结论下颌三焦点牵张成骨技术整复颏部的骨缺损过程中,下颌双侧牵张间隙与正中的压缩区组织中血管新生与新骨的生成之间存在紧密的时空联系。

The experimental study of proliferating vessels during trifocal mandibular distraction osteogenesis

Objective To study the spatial and temporal features of proliferating vessels during trifocal mandibular distraction osteogenesis (DO). Methods The mandibular symphyseal defects were made in 4 rhesus monkeys 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 trifocal distraction osteogenesis was applied to repair the mandibular symphyseal defects by the custom-made multiplanar adjustable distraction apparatus. X -ray films were used to detect the bilateral transport segments movement and the new bone formation. SEM microvascular corrosion casting study was used to examine the spatial and temporal features of proliferative vessels within distraction gap and united areas between bilateral transport discs. Results During distraction period blood vessels from bone marrow and periosteum were regenerated into distraction gap and began to form vasucular network. In the early phase of fixation period, the orientation of vein sinus was in accord with distraction orientation and the regeneration of vessels was seen. Along with the time, more vessels were connected, regeneration of vessels vanished, and the vascular system within distraction gap became more mature. Conclusion The process of angiogenesis during DO may be closely related to the osteogenesis.