Biliary Stent Valve Design for Backflow Prevention
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Solution Overview
Problem
Conventional biliary stents face challenges in reducing their length while maintaining effective valve function, as shortening the membrane can lead to backflow from the duodenum to the gallbladder due to pressure imbalances.
Innovation Solution
A biliary stent design featuring a radially expandable tubular stent body with a bile outflow port supported by two opposing support members that exert forces away from each other, maintaining the bile outflow port in a linear shape to prevent backflow, even under pressure imbalances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the length of the membrane is reduced to shorten the entire stent, then the overall stent length is reduced, but the membrane may turn over toward the gallbladder when duodenal pressure exceeds gallbladder pressure, causing loss of valve function
Solution Approach 1:
The membrane is divided into multiple segments by introducing fold lines, creating a multi-leaf structure that can independently control opening and closing movements. This segmentation allows the membrane to maintain its valve function with reduced overall length, as each segment can be optimized for specific pressure conditions without requiring the entire membrane to be excessively long.
Solution Approach 2:
The membrane is designed with dynamic characteristics through its foldable structure, allowing it to adapt its configuration based on pressure conditions. When gallbladder pressure exceeds duodenal pressure, the membrane opens to allow bile flow; when duodenal pressure exceeds gallbladder pressure, the membrane closes to prevent backflow. This dynamic behavior enables effective valve function with a shorter membrane length.
2Length of moving object
If the membrane length is simply reduced, then the stent length is shortened, but the membrane cannot maintain its protruding direction under pressure imbalance, leading to backflow prevention failure
Solution Approach 1:
The membrane is designed with curved surfaces and fold lines that create a multi-leaf structure. This curvature allows the membrane to maintain its protruding direction toward the duodenum even when pressure conditions change, as the folded structure provides structural stability while allowing controlled movement for valve function.
3Reliability
If a conventional long membrane is used to ensure valve function, then backflow prevention is reliable, but the entire stent length becomes excessive
Solution Approach 1:
By segmenting the membrane into multiple leaves with fold lines, the invention achieves reliable backflow prevention with a shorter overall membrane length. The segmented structure allows each leaf to contribute to the valve function, providing robust backflow prevention without requiring an excessively long single-piece membrane.
Data Source
Figure 1A~1D
Figure 2A~2C
Figure 3A~3C
AI summary
The purpose of the present invention is to provide a biliary stent making it possible to sufficiently exhibit a valve function while reducing the entire length of the biliary stent as compared to conventional ones. The present invention is a biliary stent (1) including a stent body (10), a tubular membrane (30) on one end of the stent body (10) and having a bile outflow port (34), and two support members (40, 50) which at one end (42, 52) are connected to the one end of the stent body (10) and at the other end (44, 54) are connected to the vicinity of the bile outflow port (34).