Undulating Stent Graft with Angular Offset Rings
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Solution Overview
Problem
Stent grafts with discrete ring stents lack stability, particularly prone to rotation or tilting during and after deployment, leading to undesirable compression or extension, which limits their effectiveness in treating vascular disorders like aneurysms.
Innovation Solution
A stent graft prosthesis with a series of ring stents having an undulating contour forming alternate peaks and valleys, where each ring stent is angularly offset with respect to adjacent ones, providing improved strength and stability while maintaining compressibility for compact delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If discrete ring stents are used in stent grafts, then the device can be compressed for compact delivery, but the stent graft lacks stability and is prone to rotation or tilting during and after deployment
Solution Approach 1:
The ring stents are configured with an asymmetric undulating contour featuring peaks and valleys at different heights, rather than a symmetric circular shape. This asymmetry creates interlocking geometry between adjacent ring stents that prevents rotation and tilting while maintaining the ability to compress for delivery.
Solution Approach 2:
The ring stents incorporate an undulating contour with curved peaks and valleys instead of straight edges. This curvature allows the stents to nest together more effectively during compression for delivery, while the three-dimensional undulating shape provides mechanical interlocking that enhances stability after deployment.
2Stability of the object's composition
If ring stents are made rigid to prevent rotation, then stability improves, but the ability to compress for catheter delivery is reduced
Solution Approach 1:
The ring stents are designed with dynamic characteristics that allow them to be flexible during delivery and rigid during function. The undulating contour with peaks and valleys enables the stents to deform and compress during catheter delivery, then lock into a stable configuration after deployment that resists rotation and tilting.
Solution Approach 2:
The undulating ring stents are designed to nest within each other during compression, with the valleys of one ring stent fitting into the peaks of adjacent rings. This nesting arrangement allows multiple rigid-seeming stents to be compressed into a compact configuration for catheter delivery, while maintaining structural integrity and stability after deployment.
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A stent graft prosthesis (10) includes a fabric sleeve (12) supported by a series of ring stents (18), including ring stents having a saddle shape with peaks (20) and valleys (22), the axial alignment of equivalently shaped ring stents in the series of ring stents being such that with respect to at least one shaped ring stent other shaped ring stents are angularly offset. Multiple series of ring stents may be interposed such that at least one ring stent in a first series of ring stents S1-Sn is located between two ring stents in at least one other series of ring stents So 1-So n, the angular offset of ring stents in the first series S1-Sn being different from the angular offset of ring stents in at least one other series of ring stents (So 1-So n). The offset changes the amount of fabric surface between peripheral contact points of successive shaped ring stents.