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This study briefly introduces the revised content of Guidance for Registration of Metallic Bone Plate Internal Fixation System (Revised in 2021) compared to the original guidance, mainly including the principles of dividing registration unit, main performance indicators of standard specification, physical and mechanical performance research, and clinical evaluation. At the same time, in order to provide some references for the registration of metallic bone plate internal fixation system, this study analyzes the main concerns in the review process of these products based on the accumulation of experience combining with the current review requirements.
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Placas Óseas , Fijación Interna de Fracturas , Fenómenos BiomecánicosRESUMEN
Objective To explore influences of the taper and connecting rib form on supporting performance of the stent, and provide an important scientific basis for structural design and clinical selection of the tapered stent. Methods A nonlinear finite element model for radial support performance of a novel balloon-expandable tapered stent was constructed, and the radial stiffness (RS) and stress distributions of the stent at different tapers (0°, 0.565°and 1.13°) and with different structural forms of stent linker (V-shape, I-shape, C-shape, S-shape, M-shape) were analyzed by plane compression. The relationship between structural design of the vascular stent and its radial support performance was studied. Results The RS of 0°stent, 0.565°stent, 1.13° stent was 2.51, 1.61, 0.85 N/mm, respectively. The RS of 0.565°stent and 1.13° stent was 35.86% and 66.14% lower than that of 0°stent (round straight stent), respectively. Except that the RS of C-shape linker stent was 1.48 N/mm, the RS of I, M, S and V-shape linker stents was not significantly different, which was 2.51, 2.61, 2.41, 2.52 N/mm, respectively, indicating that radial compression resistance of these four linker stents was almost the same. Conclusions Compared with traditional round straight stents, the RS of tapered stents will decrease, and the RS of stents will gradually decrease with the the taper increasing. Among all stent types in this study, except C-shape linker stents, the RS of other linker shapes has little effect on the RS of stents. The radial support performance of the stent can be improved by reducing the taper of the tapered stent, without changing the form of stent connecting ribs.
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Objective To compare and analyze the mechanical performance of a new biodegradable stent and a common stent and their effects on treating the stenotic vessels. Methods Using finite numerical simulation, the new stent and the common stent were implanted into vessels with a diameter stenosis of 30%, and their support performance and influences on reshaping the stenotic vessels were investigated. Results The radial recoiling ratio and dog-boning ratio of the new stent were decreased by 26.6% and 34.7%, respectively, compared with the common stent. Besides, the stenotic vessel deployed with the new stent recoiled less and had a flatter and larger lumen. Conclusions Compared with the common stent, the new stent has stronger scaffold performance and a better therapeutic effect on stenotic vessels. The new stent with stronger scaffold performance is highly expected to be an alternative choice in interventional surgeries.
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In the research of artificial joint biomechanics, it is a common method in the world to evaluate the biomechanical properties of the implanted fixtures through experiments . The domestic research started late, and the corresponding testing software were lacking. There is still no special software. In this paper, an integrated software test system was designed and built based on the existing hardware system, including:hardware control, data collection, data save, data processing and display. It can directly show the 3D motion trajectory and the angle curve of joints. The system can accurately measure the relative motion angle value, external torque value, and inter pressure value of each joint. It has some reference significance for the development of the artificial joints' evaluation system.
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The mechanical properties of artificial intervertebral disc (AID) are related to long-term reliability of prosthesis. There are three testing methods involved in the mechanical performance evaluation of AID based on different tools: the testing method using mechanical simulator, specimen testing method and finite element analysis method. In this study, the testing standard, testing equipment and materials of AID were firstly introduced. Then, the present status of AID static mechanical properties test (static axial compression, static axial compression-shear), dynamic mechanical properties test (dynamic axial compression, dynamic axial compression-shear), creep and stress relaxation test, device pushout test, core pushout test, subsidence test, etc. were focused on. The experimental techniques using specimen testing method and testing results of available artificial discs were summarized. The experimental methods and research status of finite element analysis were also summarized. Finally, the research trends of AID mechanical performance evaluation were forecasted. The simulator, load, dynamic cycle, motion mode, specimen and test standard would be important research fields in the future.
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Objective To investigate mechanical performances of two different drug eluting stents (DES) during compression process, so as to provide a scientific guideline for design of DES. Methods Using Solidworks, two kinds of stent models, namely the common DES without slots in outside surface (Stent I) and the targeted DES with slots in outside surface (Stent II) were established, respectively. The important mechanical properties of the two stents during compression process, such as rebound ratio of radial contraction, rebound ratio of axial contraction, the inhomogeneity of compression and the distribution of residual stress, were analyzed by ABAQUS. Results With the same outer radius, the difference values of rebound ratio of radial contraction, rebound ratio of axial contraction and inhomogeneity of compressing for the two stents were 0.07%-0.12%, 0.016%-0.033% and 0.013 %-0.048%, respectively; there was a bigger low-stress area on the support of Stent II. Conclusions Compared with the traditional DES, the targeted DES could maintain the same mechanical performances while reducing drug-loading capacity, which shows a good prospect in clinical application of the treatment for cardiovascular stenosis diseases.