Park Chang-Ju, Kim Hyeon-Woo, Jeong Sangdo, Seo Seungwan, Park Yangkyu, Moon Hong Sang, Lee Jong-Hyun
1 Department of Medical System Engineering, Gwangju Institute of Science and Technology (GIST) , Gwangju, South Korea .
2 School of Mechotronics, Gwangju Institute of Science and Technology (GIST) , Gwangju, South Korea .
J Endourol. 2015 Aug;29(8):933-8. doi: 10.1089/end.2015.0154. Epub 2015 May 11.
This article aims to describe the design of an anti-reflux ureteral stent with a polymeric flap valve and the fabrication methods using three-dimensional (3D) printing. The stent effectively prevents backward flow with a negligible reduction in forward flow. Fabrication of miniaturized valves was easy with high precision and rapid prototyping.
The proposed stent comprised a 7F Double-J (DJ) stent and a polymeric flap valve. The valve was made of Tango Plus FLX980 and was fabricated using a 3D printer. Two types of stent were prepared for in vitro tests: DJ stents with (1) an uncoated valve (UCV) stent and (2) a parylene C coated valve (PCV) stent for enhanced biocompatibility. The flow characteristics of each stent were evaluated considering flow direction, parylene coating, and stent side holes, and were compared to the intact DJ stent.
The forward flow rate for the distal portion of the UCV and PCV stents was 9.8 mL/min and 7.8 mL/min at applied pressure of 15 cm H2O (normal anterograde pressure in patients with stents), respectively. Backward flow rate for the distal portion of the UCV and PCV stents was decreased by 28 times and 8 times at applied pressure of 50 cm H2O (maximum bladder pressure), respectively, compared with the distal portion of the intact DJ stent. Forward flow rates of whole stents were 22.2 mL/min (UCV stent) and 20.0 mL/min (PCV stent) at applied pressure of 15 cm H2O, and backward flow rates of whole UCV and PCV stents were decreased by 8.3 times and 4.0 times at applied pressure of 50 cm H2O, respectively, compared with the intact DJ stent.
The anti-reflux ureteral stent was successfully designed and fabricated using a 3D printer. In vitro studies showed that the stent effectively prevented backward flow while minimizing reduction in forward flow.
本文旨在描述一种带有聚合物瓣阀的抗反流输尿管支架的设计以及使用三维（3D）打印的制造方法。该支架能有效防止逆流，同时顺流减少可忽略不计。小型阀的制造简便，精度高且能快速成型。
所提出的支架包括一个7F双J（DJ）支架和一个聚合物瓣阀。该阀由Tango Plus FLX980制成，使用3D打印机制造。制备了两种类型的支架用于体外测试：（1）无涂层瓣膜（UCV）支架和（2）聚对二甲苯C涂层瓣膜（PCV）支架，以增强生物相容性。考虑流动方向、聚对二甲苯涂层和支架侧孔，评估每个支架的流动特性，并与完整的DJ支架进行比较。
在15 cm H2O（支架置入患者的正常顺行压力）的施加压力下，UCV和PCV支架远端的顺流速率分别为9.8 mL/min和7.8 mL/min。与完整DJ支架的远端相比，在50 cm H2O（最大膀胱压力）的施加压力下，UCV和PCV支架远端的逆流速率分别降低了28倍和8倍。在15 cm H2O的施加压力下，整个支架的顺流速率分别为22.2 mL/min（UCV支架）和20.0 mL/min（PCV支架），与完整DJ支架相比，在50 cm H2O的施加压力下，整个UCV和PCV支架的逆流速率分别降低了8.3倍和4.0倍。
使用3D打印机成功设计并制造了抗反流输尿管支架。体外研究表明，该支架能有效防止逆流，同时使顺流减少最小化。
