Total auricular reconstruction using nitinol shape memory alloy stent: Scanning electron microscope verification of surrounding tissue structure changes at 6 and 12 months after implantation / 中国组织工程研究

ABSTRACT

BACKGROUND: Plenty of materials have been used as stent in total auricular reconstruction with varying advantages and disadvantages. The in vitro prepared tissue engineered complex cartilage stent has been not applied in clinic.OBJECTIVE: To observe the ultrastructure changes of surrounding tissues following total auricular reconstruction with nickel-titanium (NiTi) shape memory alloy stent in vivo.DESIGN, TIME AND SETTING: The randomized, controlled, animal experiment was performed in the Central Laboratory of EENT Hospital of Fudan University, Anhui Provincial Hospital and Department of Nuclear Medicine, Huashan Hospital of Fudan University from April 2004 to October 2005.MATERIALS A total of 12 New Zealand rabbits were randomized divided into the skin-expanded and unexpanded groups, with 6 animals in each group.METHODS: Each animal underwent subcutaneous implantation with a NiTi alloy stent like human auricle. In the skin-expanded group, the stent was implanted after skin expansion, while no treatment in the unexpanded group.MAIN OUTCOME MEASURES: The ultrastructure changes of surrounding tissues were detected by scanning electron microscope at months 6 and 12 after implantation.RESULTS: Structure of nickel-titanium alloy implant stent make fibrovascular ingrowth more easily. The surface of nickel-titanium alloy stent was smooth without corrosion. There was no evidence of infection in the host tissue. Microstructure of Ni-Ti stent wires showed no morphologic and functional changes after subcutaneously implanted in vivo, and the difference between 2 groups had no significance.CONCLUSION: NiTi shape memory alloy stent can smoothly pass the process of fibrovascularization with less complication.According to the examination by SEM, the nickel-titanium stent showed good biocompatibility.