Stent Graft Membrane Fixation Between Ring Segments
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Solution Overview
Problem
State-of-the-art stent grafts face issues with durable connection between the stent and membrane, leading to potential tissue irritation and instability under high frictional forces, especially when hooks or threads are used for reinforcement, and expansion can impair membrane fixation.
Innovation Solution
A stent graft design where the membrane is fixed between loops of the second ring segments and connecting webs, with elongated loops and blind webs providing secure fixation without protrusions, ensuring the membrane is retained effectively during and after stent expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If hooks or threads are used to connect stent and membrane, then connection strength is improved, but tissue irritation and durability under frictional forces worsen
Solution Approach 1:
The invention removes hooks and threads from the design entirely, extracting the harmful elements that caused tissue irritation while maintaining connection functionality through an alternative mechanism involving membrane folding and compression between stent components
Solution Approach 2:
The membrane itself acts as an intermediary element, being folded and compressed to create the connection between stent and membrane, eliminating the need for separate connecting elements like hooks or threads that caused tissue damage
2Reliability
If hooks or threads are used for reinforcement, then connection durability is improved, but frictional force resistance worsens
Solution Approach 1:
The invention extracts hooks and threads from the connection mechanism, replacing them with a folded membrane structure that distributes frictional forces across a larger area, preventing the concentration of stresses that led to durability problems
Solution Approach 2:
The membrane is utilized as a flexible element that is folded and compressed to create the connection, allowing it to accommodate frictional forces through deformation rather than relying on rigid hooks or threads that failed under stress
3Reliability
If membrane is fixed at peripheral ring segments, then fixation security is improved, but expansion capability worsens
Solution Approach 1:
The membrane is folded and compressed in advance during the crimping process, creating pre-formed connection points that maintain fixation security while allowing the stent to expand freely during deployment without impairing the membrane-stent connection
4Strength
If traditional stent graft design is used, then structural support is improved, but vascular lumen consumption worsens
Solution Approach 1:
The stent structure is divided into terminal ring segments and intermediate ring segments, with the membrane connection specifically implemented at the terminal segments, allowing optimized structural support while minimizing overall device profile and vascular lumen consumption
Data Source
AI summary
Stent graft consisting of a stent (1) comprising a plurality of ring segments (3, 4) having a meandering configuration arranged side by side and connected with each other by connecting webs (6), and at least one membrane (2) covering the entire outer side of the stent (1), being wrapped inwards around the ends of the stent and fixed between loops of ring segments (4) and connecting webs (6) that join the adjacent ring segments (3, 4) with each other, wherein the membrane (2) is fixed between at least two loops of the second ring segment (4), viewed from the ends of the stent (1), and the connecting webs (6) to the neighboring terminal ring segment (3).