Stent Graft Introducer Constrained Deployment Curved Lumen
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Solution Overview
Problem
Deploying stent grafts in curved lumens, such as the aorta, is challenging due to curvature mismatch, leading to improper placement, kinking, and potential blood flow restrictions, as existing methods require the stent graft to follow the lumen's curvature, which can result in gaps and buckling.
Innovation Solution
An introducer system that constrains specific stents of the stent graft during deployment, allowing it to expand and securely anchor within the curved lumen without matching the curvature, using loops of material for wire engagement to maintain stents in a constrained state, enabling proper positioning and expansion within the vessel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the stent graft is deployed to follow the curvature of the lumen, then the stent graft can be placed in a curved vessel, but the stent graft may not sit properly, kinks can occur, and the lumen diameter can be reduced
Solution Approach 1:
The stent is divided into multiple individual stent elements that can be independently constrained or released. This segmentation allows selective control over which portions of the stent expand and which remain constrained, enabling proper deployment in curved lumens without causing kinks or reducing lumen diameter.
Solution Approach 2:
The stent elements are pre-constrained in a compressed state within the introducer device before deployment. This preliminary constraining allows the stent to be navigated through the curved lumen in a compact form, and then selectively released to expand only where needed, ensuring proper placement without curvature matching.
2Adaptability or versatility
If a substantially cylindrical stent graft is deployed in a curved aorta, then the stent graft can be placed in the vessel, but the proximal end may not lie flat against the walls and blood can flow underneath causing buckling
Solution Approach 1:
Different portions of the stent are treated differently - some stent elements are constrained while others are free to expand. This local differentiation ensures that the proximal end of the stent graft lies flat against the vessel walls to prevent blood flow underneath and buckling, while other portions can accommodate the curvature of the lumen.
Solution Approach 2:
The introducer device acts as an intermediary that maintains the stent elements in a constrained state during navigation through the curved lumen. The introducer's structure, including the inner catheter and pusher member, mediates the deployment process to ensure proper positioning before release.
3Shape
If the stent elements are spaced with greater distance on the outer curved side than on the inner curved side, then the stent can conform to the curve, but the structure becomes more complex and manufacturing more difficult
Solution Approach 1:
The stent structure incorporates movable stent elements that can dynamically adjust their spacing and configuration. The stent elements are attached in a way that allows them to move relative to each other, enabling the stent to conform to curved lumens without requiring complex pre-spaced configurations that would be difficult to manufacture.
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
Enables secure deployment of stent grafts in curved lumens without curvature matching, preventing kinking and ensuring proper blood flow by maintaining stents in a constrained state during expansion, allowing for effective engagement with vessel walls and minimizing gaps.
Implementation Method 1
the stent graft can expand under the action of the self-expanding stents towards the vessel walls to redefine the blood flow path
Data Source
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AI summary
An introducer (10) includes release wires (42') that constrain at least one stent (4') whilst the remainder of a stent graft (18) is expanded during deployment. By allowing the constrained stent (4') to expand after an adjacent stent (4), the constrained stent (4') overlaps with the interior of the adjacent stent (4) where the stent graft (18) is deployed within a curved body lumen (70).