Variable Spacing Stent Graft for Aneurysm Repair
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Solution Overview
Problem
Existing stent grafts for treating abdominal and iliac aneurysms lack optimal bending properties, adhesion, and production efficiency, with issues such as poor flexibility, uneven diameter changes, and untreated filament ends leading to potential damage and reduced strength.
Innovation Solution
A stent graft design featuring a stent body divided into small, transition, and large diameter sections with varying distances and edge heights, along with flush end surfaces and treated filament ends, woven from a memory alloy filament to enhance flexibility and adhesion, and improve production efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the stent graft is designed with uniform diameter throughout, then the manufacturing process is simpler, but the bending properties and adaptability to curved blood vessels are poor
Solution Approach 1:
The stent graft is designed with different diameter sections (narrowing section and expanding section) to provide different properties in different locations. The narrowing section has smaller diameter for better bending properties in curved vessels, while the expanding section has larger diameter for adequate support in straight sections, resolving the contradiction between manufacturing simplicity and bending adaptability
2Reliability
If the distance between adjacent spiral stent sections is reduced, then the adhesion property is improved, but the bending flexibility deteriorates
Solution Approach 1:
The patent applies different spacing between spiral stent sections in different regions: smaller spacing in the narrowing section for better adhesion, and larger spacing in the expanding section for better bending flexibility. This local differentiation resolves the contradiction between adhesion and flexibility
3Device complexity
If the stent sections are woven with zero angle between adjacent edges, then the manufacturing complexity is reduced, but the fatigue strength and structural integrity are compromised
Solution Approach 1:
The patent specifies that the angle between adjacent edges of spiral stent sections should be between 5-15 degrees in the narrowing section and 15-30 degrees in the expanding section. This non-zero angle design improves fatigue strength and structural integrity while maintaining acceptable manufacturing complexity
4Ease of manufacture
If the filament ends are left untreated, then the manufacturing process is simpler, but the graft may suffer from damages and reduced reliability
Solution Approach 1:
The patent applies preliminary treatment to the filament ends (such as sealing, coating, or fraying control) before final assembly. This preliminary action prevents graft damage during handling and implantation, improving reliability while adding minimal manufacturing steps
5Strength
If the stent graft has large diameter change between sections, then the support strength is improved, but the bending properties and adhesion deteriorate
Solution Approach 1:
The stent graft is segmented into multiple sections (narrowing section with 3-7 spiral stent sections and expanding section with 3-7 spiral stent sections) with gradual diameter transitions. This segmentation allows the structure to provide support strength where needed while maintaining bending properties through gradual transitions rather than abrupt changes
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The stent graft achieves improved bending properties, increased pull-out force, and enhanced roundness and adhesion, ensuring effective isolation of aneurysms while maintaining smooth blood flow, with precise parameter settings and efficient production.
Implementation Method 1
woven from a memory alloy filament to enhance flexibility and adhesion
Data Source
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AI summary
A coated stent graft (1) includes a stent body (2) and a graft (3) fixed on the stent body (2), the stent (2) body being divided into a plurality of stent sections (7) along a center axis (X) of the stent graft (1), each stent section (7) extending around the center axis (X) by one circle, wherein each stent section (7) is formed by connecting a plurality of wave rods (8) end to end in a wavy structure. The stent body (2) consists of a small diameter section (4), a transition section (5) and a large diameter section (6) along the center axis (X), and the transition section (5) connects the small diameter section (4) with the large diameter section (6), wherein a distance between adjacent stent sections in the transition section (5) is larger than a distance between adjacent stent sections in the small diameter section (4), and is smaller than a distance between adjacent stent sections in the large diameter section (6). The stent graft (1) of the invention has improved bending properties.