Tomizawa Yasuko, Hanawa Takao, Kuroda Daisuke, Nishida Hiroshi, Endo Masahiro
Department of Cardiovascular Surgery, The Heart Institute of Japan, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo, 162-8666, Japan.
J Artif Organs. 2006;9(1):61-6. doi: 10.1007/s10047-005-0321-0.
A variety of metallic components have been used in medical devices where lifelong durability and physical strength are demanded. To investigate the in vivo changes of implanted metallic medical devices in humans, stainless steel sternal wires removed from patients were evaluated. Stainless steel (316L) sternal wires removed from four patients after 10, 13, 22, and 30 years of implantation were evaluated using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Macroscopically, the removed specimens maintained their metallic luster and color. Under SEM, small holes were observed sporadically at 10 years and they tended to connect in the drawing direction. The longer the implanted duration, the more numerous and deeper were the crevices observed. By EDS, sulfur, phosphorus, and calcium were identified in all areas at 10 years, in addition to the component elements of stainless steel, comprising iron, chromium, nickel, and manganese. Corrosion products observed at 30 years were identified as calcium phosphate. In conclusion, stainless steel sternal wires develop corroded pores that grow larger and deeper with time after implantation; however, the pores remain shallow even after decades of implantation and they may not be a cause of mechanical failure. An amount of metal ions equivalent to the corroded volume must have been released into the human body, but the effect of these metal ions on the body is not apparent.
各种金属部件已被用于需要终身耐用性和物理强度的医疗设备中。为了研究植入人体的金属医疗设备的体内变化，对从患者体内取出的不锈钢胸骨钢丝进行了评估。使用扫描电子显微镜（SEM）和能量色散X射线光谱仪（EDS）对植入10年、13年、22年和30年后从4名患者体内取出的不锈钢（316L）胸骨钢丝进行了评估。宏观上，取出的标本保持了它们的金属光泽和颜色。在扫描电子显微镜下，10年后偶尔会观察到小孔，并且它们倾向于在拉伸方向上连接。植入时间越长，观察到的缝隙就越多、越深。通过能谱分析，除了不锈钢的组成元素铁、铬、镍和锰之外，在10年时所有区域都检测到了硫、磷和钙。30年时观察到的腐蚀产物被鉴定为磷酸钙。总之，不锈钢胸骨钢丝会形成腐蚀孔，植入后随着时间的推移，这些孔会变得更大更深；然而，即使经过几十年的植入，这些孔仍然很浅，它们可能不是机械故障的原因。一定量与腐蚀体积相当的金属离子必定已释放到人体中，但这些金属离子对人体的影响并不明显。
