弹性镍钛记忆合金牵张成骨修复犬腭裂

Distraction Osteogenesis for the Closure of Cleft Palate in Dogs by Persistent Elastic Force

目的:研究镍钛记忆合金牵张成骨修复犬腭裂的愈合过程。方法:健康杂种幼犬8只,建立人工腭裂模型。1周后,在6只实验组犬硬腭上制作骨转移盘,植入镍钛记忆合金牵张装置,用300g的力持续向内侧和后侧牵引,关闭硬腭裂隙后保持3周。再分别于2、4、8周处死动物模型,采用直接观察、X线和组织学方法评价记忆合金与组织的相容性及中线骨组织愈合情况。结果:牵张8～10d后裂隙关闭,骨组织后移,硬腭平均延长4.5mm,两侧骨板在中间融合。结论:记忆合金牵张成骨可使腭部两侧骨板在中线区形成骨融合。

Objective： The purpose of this study was to investigate the process of closing a cleft by the technique of distraction osteogenesis with elastic force. Methods： 8 mongrel dogs, in weanling were used in this study. An 8mm width midline portion of the hard palate was surgically resected in all dogs, which included mucoperiosteum and underlying palate bone, and nasal septum from the transverse palatal was sutured to the distal bone margin. One week later, a distractor made of TiNi shape memory alloy, which producted a continues traction force of 300 g medially, and distally was inserted in palate of 6 experiment dogs. The continuous distraction began without any latency after the installation and persisted for 3 weeks after the gap had been closed.Dog were killed at 2,4,8 weeks later, and assessment of the bone closure were examined by gross examination, histological and radiological methods. Results： The cleft in all dogs were completely closed over a distration period of 8 to 10 days.The X-ray films revealed that the bone islands in the experimental dogs moved medially and distally. The histological study showed that the middle line healing was firstly occurred through epithelial union, and then new bone formation ,bone bridge eventually connected bilateral bone islands. Conclusion： Shape memory alloy can be used in distraction osteogenesis to Close the hard palate cleft in dogs.