Development of new stent made of the composite of medical polymer and shape memory allow.

新的支架被设计用来防止气道塌陷。采用钛镍形状记忆合金与医用高分子复合材料制成新型支架。支架的结构被设计成类似于天然气管的结构，即它是具有横向外观的软管鞋形状的管。为了避免金属合金直接附着在宿主组织上，支架表面覆盖了医用级硅胶，我们原计划使用新型形状记忆丝制作新的支架。然而，由于关西大地震，我们的研究合作伙伴科比钢铁公司在科比的研究中心于1995年1月17日被完全摧毁。工厂以及数据和材料都不再使用。经过半年左右的时间，系统恢复到制造形状记忆合金的状态。尽管有这些困难，我们还是制作了金属铸件来制造支架丝管。用直径为0.5mm的钛镍丝制作支架管的支架结构。然后，我们将硅胶片与尼龙网加固的硅橡胶结合在一起。硅胶片内的目的是促进气道分泌物的排出。将这种新研制的支架应用于预防犬气道塌陷。1996年1月开始动物实验。到目前为止，我们在12只比格犬植入了支架，这些犬的气管是预先破坏的，因此它们变成了气管软化。所有犬植入后的临床过程均顺利。结果在京都日本胸外科协会年会上报告。由于我们的支架使用金属材料，在临床上患者被认为暴露于MRI条件。因此，为了证实支架在这种情况下的安全性，我们研究了金属在MRI检查中的安全性，并在期刊上进行了报告。

New stent was designed to prevent the collapse of the air way. New stent was made from the composite of Ti-Ni shape memory alloy and medical polymer. The structure of the stent was designed to resembling to that of the native trachea, namely it is a tube with a transverse appearance hose shoe shape. In order not to attach the metallic alloy directly to the host tissue, the stent was covered with medical grade silicone.In the original plan, we intended to make new stent using the novel shape memory wire. However, because of the Big Earthquake in Kansai, the research center of the our research partner Kobe Steel Company in Kobe was destroyed completely on 17th January 1995. The plant as well as the data and material became out of use. It took about half year to recover the system to make the shape memory alloy. In spite of these difficulties, we made a metallic cast of manufacture the stent wire tube. Using the Ti-Ni wire with a diameter of 0.5 mm, balk structure of the stent tube was made. Then, we combined the silicone sheet inside on this balk with the silicone rubber reinforced with nylon mesh. The aim of the silicone sheet inside is to facilitate the drainage of the secretion of the airway. This newly developed stent was applied to the prevention from the airway collapse in dogs. Animal experiment began in January 1996. Until now, we implanted the stent in 12 beagle dog, whose trachea was previously destroyed in advance, so as they became the tracheomalacia. The clinical course after the implantation was uneventful in all dog. The results are reported on the annual meeting of Japanese Association for Thoracic Surgery in Kyoto.Because our stent use the metallic material, in clinically patients are considered to be exposed the MRI condition. Therefore, in order to confirm the safety of the stent in such condition, we study the safety of the metal at the MRI examination and reported it on a journal.