Experimental Study On Permanent Magnesium Alloy Stent Implantation For Congenital Tracheal Stenosis In Infants And Children

Congenital tracheal stenosis is a life-threatening disease for infants and young children.The pathogenesis mechanism of this disease is still unclear.Currently,the treatment strategy of the disease is surgical correction combined with comprehensive internal medicine.However,it is still lack of effective treatment standard.Biodegradable tracheal stent is an important research approach in the future treatment for infants and young children with congenital tracheal stenosis.In this subject,we cooperated with the school of Materials Science and Engineering,Tianjin University and Shanghai Jiaotong University.In previous studies,the former has designed and synthesized Mg-Ca-Zn alloy,and has done a great deal of research about magnesium alloy's machining and synthesis,surface treatment,mechanical testing.The another institution has developed a new type of magnesium alloy for biomedical—JDBM magnesium alloy,and has already begun taking steps to clinical use.Two cooperative institutions provide us with several different components of the magnesium alloy.Based on these studies,we further carried on a study of cytotoxicity test and animal experiment.Nowadays,magnesium alloy stent permanently implanted in children is a new treatment idea for trachea stenosis.The subject of study consists of three parts.In the first part,a primary extract and culture method of rabbit tracheal epithelial cells by protease ablation was explored.Through repeated tests and exploration,the rabbit tracheal epithelial cells were extracted successfully,which were high purity and better vitality.The second part of the study focused on cytotoxicity test of magnesium alloy material.Experimental results showed that different components of the magnesium alloy material provide by the two institutes have low cytotoxicity.The degree of cytotoxicity were slight or mild.Accordingly,the magnesium alloy material has an excellent biocompatibility.The third part was mainly about the animal experiment.We firstly explored a simple tracheal stents implantation method for experimental animals--under the guidance of the fiberoptic bronchoscopy by directly vision,and then put the tracheal stent into the airway with the guide of rigid bronchoscope.Using this method,the tracheal stents were successfully placed in rabbits' trachea.On this basis,we further studied the mechanical property of magnesium alloy stent,the ablation process of stents in the airway,and the effects on the body.The result showed that the mechanical property of JDBM magnesium alloy material tracheal stent is able to match the requirements of the rabbit airway.Moreover,the placement of the stents did not lead to serious inflammation and induce the growth of granulation tissue in the airway.Additionally,it had not obviously negative affect on the vital organs of the body.According to the results,we concluded it is a feasible proposal to use tracheal stent made of magnesium alloy materials for the treatment of tracheal stenosis.Therefore,it is a new treatment idea for infants and children with tracheal stenosis.