Comparison of the microstructures and properties of different microcannulas for HA injection

BACKGROUND: Microcannulas are used for hyaluronic acid and other fillers injection and reduce the side effects and complications. There are several microcannulas manufactured by different manufacturers but the differences between microcannulas haven't been carefully investigated. OBJECTIVE: To compare the microstructures and properties of different microcannulas by several trials and provide guidance for clinical application. METHODS: In this study, 9 kinds of microcannulas, from different manufacturers were chose. Scanning electron microscope(SEM) was used to obtain high-definition image of microstructures, chemical composition analyzers were used to test the chemical composition for the microcannulas' tips and universal testing machine was used to measure mechanical properties. Injection speed test recorded the time spent for the weight pushed hyaluronic acid out during different microcannulas. Vessel piercing force test was conducted to simulate the process of puncturing the vessels in vitro. RESULTS: The SEM images showed the differences in the tips and inner surfaces which may relate to the characteristics. Most microcannulas' chemical composition met the American Society for Testing Material(ASTM) standards basically. For mechanical properties, the elastic modulus and the yield strength were obviously different. The injection speed test showed the speed of difference microcannulas through same force was discrepant more than 7 times. The vessel piercing test showed which microcannula was most difficult to puncture the aorta and which was the easiest. CONCLUSION: The results indicated there are significant differences between different microcannulas. The differences are instructive to physician to select suitable microcannulas to improve the injection effect and reduce discomfort and complications. Financial disclosure: The authors have no financial interest to declare in relation to the content of this article. Acknowledgement: none Corresponding author: Wang Hang, Sichuan Univ, West China Sch Stomatol, Dept Oral & Maxillofacial Surg, 14,3rd Sect,RenMin Nan Rd, Chengdu 610041, Peoples R China. Tel: +86 13980888813, E-mail:dr.hangwang@hotmail.com ©2018American Society of Plastic Surgeons