记忆合金椎体支架在猪椎骨内的植入实验

Implanting experiment of memory alloy vertebral stent in pig vertebrae

目的探讨记忆合金椎体支架在动物椎体内扩张支撑的初步结果,检验支架设计的可操作性。方法将自行研制的记忆合金可扩张椎体支架植入猪椎体,可吸收骨材料填充入椎体支架空腔内。实验对同一猪选择两节椎体L1、L3间隔植入的对照方式。本次实验选用3头大白猪:1号猪(编号8420)、2号猪(编号8439)、3号猪(编号8424),分7、13、26周3个时间观察点作为终末结果观察节点。术后4周与实验预定结束时间点前1周采集X线片,实验结束后取标本的Micro-CT影像观测支架在猪椎体内的植入情况,对支架在椎体内的稳定性和支架扩张结果进行分析。结果支架在植入椎体内的操作过程中顺利,获得微创置入预期;支架植入椎体内如期扩张并且随即稳定卡在椎体空腔内。在本实验的观察过程中,2号猪(编号8439)术后出现犬坐,术后3 d恢复正常行走,但在第46 d发现死亡,检查后为睾丸疝,因与实验时间差距不大,其实验结果被列入观察,将2号猪(编号8439)与1号猪(编号8420)互换观察,1号猪(编号8420)与3号猪(编号8424)完成后两组实验观察。支架植入猪椎体在影像观察中未见滑移、移出椎体。大体标本观察,支架均稳定在椎体内。支架在植入后4周与处死前1周的影像测量中高度略有变化,术后4周支架影像测量高度为(8.967±0.952)mm,处死前1周的支架影像测量高度为(9.532±0.708)mm,两者比较差异有统计学意义(P<0.05)。结论记忆合金椎体支架具有良好的临床可操作性与椎体内植入的安全性,具有良好的力学支撑和椎体内的可扩张性能;记忆合金可扩张椎体支架对于椎体压缩骨折的微创治疗是一项有前景的微创技术。

Objective To investigate the preliminary results of the extended support of the memory alloy vertebral stent in animal vertebrae and to test the operability of the stent design.Methods In this experiment,self-developed expandable memory alloy vertebral stents were implanted in porcine vertebral bodies.Resorbable bone material was filled into the cavities of the vertebral stents.In the experiment,two vertebral bodies,L1 and L3,were selected for the interval implantation method in the same pig.Three white pigs(pig No.1:number 8420;pig No.2:number 8439;pig No.3:number 8424)were selected as the final observation points at 7,13 and 26 weeks.X-ray films were collected immediately after surgery and one week before the scheduled end time of the experiment.The Micro-CT images of specimens were collected after the experiment to observe the implantation of the stents in the pig vertebrae and the stability of the stents in the vertebrae and the results of stent expansion were analyzed.Results These stents were successfully implanted in the vertebrae of these pigs.The expectation of minimally invasive implantation was met.These stents were implanted into these pigs vertebrae and expanded as scheduled and then stabilized into the vertebral cavities.During the observation of the experiment,pig No.8439 showed"canine sitting"after operation and recovered to stand and walk normally three days later.Unfortunately,it was found dead on day 46 with a testicular hernia.The experimental results were included in the observation due to the small gap with the experimental time.The experimental observation of pig No.8420,originally scheduled,was changed.The experimental observation of pig 8420 and pig 8424 was completed.No slippage or displacement of the pig vertebrae was observed during the imaging observation.The stents were all stable in the vertebral bodies.The height of these stents 4 weeks after implantation changed slightly compared with that of the week before the end of the experimental observation,which was(8.967±0.952)mm after surgery and(9.532±0.708)mm one week before the end of the experimental observation,there was statistical significance(P<0.05).Conclusion The memory alloy vertebral stent has a good clinical operability and safety of vertebral implantation it has a good mechanical support and expandable performance in vertebral body.The expandable memory alloy vertebral stent is a promising minimally invasive technique for the minimally invasive treatment of vertebral compression fractures.