鎳鈦合金於植入式醫療器材上的多種應用

Applications of Nitinol in Implantable Medical Devices

柯俊誼(Chun-Yi Ko)

指導教授 ： 蕭浩明

國立臺灣大學/工學院/機械工程學研究所/碩士(2016年)

https://doi.org/10.6342/NTU201600896

摘要

鎳鈦合金具備特殊的材料性質，且經過適當處理後具備優秀的生物可相容性，因而被廣泛應用於植入式醫療器材上。本研究以鎳鈦合金作為材料，提出了三款不同的植入式醫療器材，其機械需求與應用範圍皆大不相同。主動脈血管支架作為新型心室輔助器(VAD)中的一部分零件，能夠提供T型轉接管足夠的支撐，使其能緊貼在血管壁上，免除兩端劇烈變形以及血栓堆積的問題。該款VAD能有效降低VAD安裝手術的風險，同時減少病人手術後的恢復時間。球型血管支架應用在顱內動脈瘤的栓塞治療法，能夠降低栓塞器材的成本，使更多的病患得以負擔，透過導管一口氣釋放的設計還能有效縮短手術時間；應用於肝癌治療上則是能在當作栓塞物的同時作為藥物載體，透過栓塞與化療藥物的同時治療，殺死腫瘤細胞，治療完成後還能在一次透過導管取回，使肝動脈恢復原本的功能。栓塞防護器(EPF)在包覆多孔聚合物薄膜後，能夠應用於各式各樣的支架置放手術，包含：頸動脈、冠狀動脈、膽管等，將手術途中上游流下的栓塞物檔下，防止下游血管的阻塞。
本研究建立了一系列的設計與製造流程：CAD參數化設計、有限元素電腦模擬、雷射切削、熱處理定型以及電解拋光等核心技術能力。製成上首先使用脈衝式光纖雷射對2mm及7mm的鎳鈦無縫管進行加工；接著使用自製的定型夾具改變雛型品的內徑與外型，並置入鹽浴爐中進行退火；最後透過氧化鋁顆粒作的噴砂處理與電解拋光作進一步的表面改良，以改善其表面粗糙度與生物可相容性。實驗最後亦比較拋光前後表面的改善情形，結果顯示拋光後的邊緣不僅更為平滑，表面起伏度也有所下降。最後利用上述的製造步驟與實驗完成三款鎳鈦合金植入式裝置的雛型品，作為概念展示。

關鍵字

鎳鈦合金 ； 主動脈血管支架 ； 球型血管支架 ； 栓塞防護器 ； 定型處理 ； 電解拋光

並列摘要

Nitinol is widely used in implantable medical devices due to its special property and outstanding biocompatibility after proper treatment. In this study, three nitinol implantable medical devices with different property requirements and applications were proposed. Aortic stent, used as a part of a novel VAD, can provide support to the T-shape transfer tube. Which allows the tube to fit the vascular wall perfectly without causing thrombosis and severe deformation. The novel VAD is able to reduce both the risk during VAD installation surgery and the time consumption for patient recovery. Spherical stent can be applied in aneurysm embolization as a less expensive option for patients due to its lower cost. Since the spherical stent can be deployed through catheter, the operation time can be significantly reduced. The spherical stents can also be applied in liver cancer treatment as not only an embolic device but a drug carrier. Both embolization and chemotherapeutic medicine can be applied at the same time to kill tumor cells. After the treatment was done, the stent can be retrieved through catheter. Recovering the blood flow of hepatic artery. The EPF needs to be enveloped by porous polymeric membrane before applied in stenting surgeries. These stenting surgeries include carotid artery, coronary arteries, bile duct, etc. The EPF can trap emboli fragments from upper stream during surgery, and prevent the blood vessel downstream from embolism.
The study has established a series of core techniques, including parametric design, finite element model, laser cutting, heat treatment and electro-polishing. Nitinol implantable devices were fist manufactured from 2mm and 7mm seamless tubes with pulsed fiber laser, followed by sequential expansion, shaping and heat treatment with designed fixtures and salt bath furnace. Finally, three devices were abraded with Al2O3 particles by-sand-blasting and then further refined by electro-polishing. Surface finish of nitinol devices improved prominently after electro-polishing, resulting in smoother edges and gentler surface undulation. Three nitinol implantable medical devices were prototyped with foregoing procedures for demonstration.

並列關鍵字

Nitinol ； Aortic stent ； Spherical stent ； Embolic protection filter ； Shape-setting ； Electro-polishing

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