Double Stent Radial Force and Membrane Anchoring
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Solution Overview
Problem
Existing stent grafts face issues with membrane anchoring, tightness, and coherence due to insufficient radial force, particularly in self-expanding stents, which can lead to membrane damage and loss of structural integrity during expansion.
Innovation Solution
A double stent design featuring an inner and outer stent with corresponding inner and outer membranes, where the membrane ends are folded inward and clamped by flexible tongues of the inner stent, enhancing radial force and coherence, with the outer membrane providing protection and compensating for potential inner membrane damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a single stent with membrane is used, then the device complexity is low, but the radial force is insufficient to securely anchor the membrane and ensure reliable vessel bridging
Solution Approach 1:
The patent combines two stents (inner and outer stents) with two membranes (inner and outer membranes) into a single integrated double stent graft device. This merging of multiple components achieves increased radial force through the cooperative action of both stents, while the membranes work together to provide both structural support and occlusion function, resolving the contradiction between force requirements and device complexity.
Solution Approach 2:
The inner stent with its membrane is nested within the outer stent with its membrane, creating a concentric dual-layer structure. This nesting arrangement allows both stents to contribute to radial force while maintaining a compact integrated device, and enables the membranes to work in conjunction for enhanced anchoring and occlusion without excessive complexity.
2Force
If the membrane is clamped between two stents during expansion, then the radial force is increased, but the membrane may be damaged or torn during the expansion process
Solution Approach 1:
The patent employs an outer membrane that serves as a protective layer for the inner membrane during the expansion process. This outer membrane cushions and protects the inner membrane from mechanical damage when the double stent is expanded, preventing tears and maintaining membrane integrity while still allowing both membranes to contribute to the overall radial force and occlusion function.
Solution Approach 2:
The double stent graft uses a composite structure with two different membranes (inner and outer) that have complementary properties. The inner membrane provides primary occlusion while the outer membrane provides protection and additional structural support. This composite membrane system resolves the contradiction by allowing the membranes to work together, with the outer membrane protecting the inner membrane from damage during expansion.
3Force
If the two stents are arranged coaxially with membranes between them, then the radial force is increased, but the coherence of the composite structure may be lost due to different expansion behavior
Solution Approach 1:
The patent merges the inner stent-memory and outer stent-memory into a single coordinated expansion system. Both stents are designed to expand cooperatively during deployment, with their expansion behaviors synchronized to maintain structural coherence. The flexible tongues and clamping mechanism ensure that both stents and membranes work together as an integrated unit, preventing loss of coherence despite the complexity of the dual-stent structure.
4Reliability
If the membrane ends are folded and clamped under flexible tongues, then the anchoring reliability is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent uses flexible tongues made of elastic material that can deform during the clamping process to secure the membrane ends. These flexible components accommodate slight variations in membrane positioning and folding, reducing the stringency of manufacturing precision requirements while still achieving reliable anchoring. The flexibility of the tongues allows them to adapt to minor dimensional variations without compromising the anchoring function.
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 double stent design ensures reliable anchoring, tightness, and structural coherence, maintaining occlusion of vascular malformations with increased radial force, suitable for both balloon-expandable and self-expanding types, and suitable for placement in stented vessel branches.
Implementation Method 1
clamped under flexible tongues of the first stent
Data Source
AI summary
The invention relates to a double stent comprising 2 coaxially arranged stents, wherein a first membrane is arranged between a first inner stent and a second outer stent and a second membrane is arranged on the second stent and wherein the membrane ends of the first and second membrane are brought together at the ends of the stents and are folded over onto the inside of the first stent and clamped under flexible tongues of the first stent.