记忆合金可扩张椎体支架设计参数与镍离子游离的初步探讨

The initial approach for design parameters of Shape Memory Alloy Expandable Vertebra Stent and its nickel ion liberation scale

目的数理学测算记忆合金椎体可扩张支架(EVS)的表面积、体积与质量,初步探讨EVS镍离子的游离量,探讨其作为体内植入物的安全性。方法对本设计的三、四、五、六瓣叶EVS自身表面积和体积进行测算,根据记忆合金镍离子相关实验数据,推算EVS的镍离子游离度;与正常人体血镍浓度、人体日生理摄入量,进行对照和分析。结果本设计的EVS每只的表面积在420mm2~900mm2之间,体积为110mm3~280mm3,质量为772mg^1968mg。EVS的镍离子体外Hanks液的测算最大峰值游离量为7517.4×10-6g^16852.44×10-6g;设计最大规格的EVS在Hanks液测算释放镍离子的理论峰值占正常人体血镍离子量的0.0034%。结论EVS的镍离子理论测算游离量极其微小,可作为椎体內的内植物。

Objective It is to measure the surface area and volume and mass of the Shape Memory Alloy Expandable Vertebra Stent （SMA-EVS） with geometry-mathematics principle. The nickel ion liberation scale will be initially measured and evaluated in order to explore the EVS clinical application feasibility for implanting into fractures spinal bodies. Methods The EVS is designed as three or four or five or six lobes whose thicknesses of the SMA plates are from 0.75mm to 1.2mm. And then, the surface area and volume and mass of the EVS could be definited its scale as the design. With the ready-made nickel ion liberation experimental results, the designed EVS surface area and volume and mass will be measured and evaluated, the nickel ion possible liberation of the stent can be calculated and defined its scale. Refering to correlative foods safety rules and data of nickel ion intaking minimal request a day and the nickel ion normal concentration in health adults and the nickel ion ingests from food a day, the EVS nickel ion liberation will be initially presumed and evaluated. The results will be contrasted to the nickel ion of blood concentration and physio-intake in human body. Results The EVS designed surface are a range is from 420mm^2 to 900mm^2. Its volume is from 110mm^3-280mm^3 and its mass is from 772mg-1968mg. The EVS maximum crest scale nickel ion liberation range is evaluated from 7517.4× 10^6μg to 16852.44μ 10^6μg range is from 420mm^2 to 900mm^2. Its volume is from 110mm^3-280mm^3 and its mass is from 772mg-1968mg. The EVS maximum crest scale nickel ion liberation range is evaluated from 7517.4× 10^-6μg to 16852.44× 10^6μg according to the laboratory measured nickel ion liberation results in Hanks liquid. The nickel ion liberation scale in Hanks liquid is about 0.0034% as blood nickel ion density. Conclusions The EVS nickel ion liberation scale is infinitesimal liberation. It can be used an implant in vertebral body.