Double Tubing Coupling Device for Stent-Graft Sealing
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Solution Overview
Problem
Existing modular prostheses face challenges in achieving a fluid-tight seal between modules and vessel walls, especially in cases where vessel dimensions vary or aneurysms occur, due to the need for precise sizing and complementary dimensions at coupling points.
Innovation Solution
A coupling device with a self-expandable inner stent and a membrane-covered outer stent, where the inner stent can expand radially inwardly to connect modules and the outer stent expands outwardly to abut the vessel wall, providing a fluid-tight seal without requiring precise vessel or module sizing, using a double concentric tube structure with bridging rings and stents on both layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If modular prostheses are coupled by nesting sections and expanding inner sections against outer sections, then fluid-tight seal between modules can be achieved, but precise manufacturing and limited design flexibility are required
Solution Approach 1:
The coupling device employs nested stent structures where an inner stent is positioned within an outer stent. The inner stent expands to engage the prosthetic module while the outer stent expands to contact the vessel wall, creating a nested configuration that ensures fluid-tight sealing without requiring precise complementary dimensions between modules.
Solution Approach 2:
The stents are designed with shape memory properties, allowing them to change their radial dimensions through phase transformation. This parameter change enables the stents to expand from a compressed delivery state to a deployed state, adapting to different vessel and module sizes without requiring precise pre-matching of dimensions.
2Reliability
If prosthesis dimensions are selected to match vessel dimensions, then fluid-tight seal at vessel interface can be achieved, but adaptability to varying vessel sizes and aneurysms is reduced
Solution Approach 1:
The coupling device incorporates dynamically expandable stents that can adjust their dimensions after implantation. The stents transition from a compressed low-profile state during delivery to an expanded high-profile state at the implantation site, allowing adaptation to various vessel sizes and aneurysm configurations while maintaining fluid-tight sealing.
Solution Approach 2:
The device is divided into functional segments: an inner stent for module engagement, an outer stent for vessel wall contact, and a membrane for sealing. This segmentation allows each component to be optimized independently for its specific function while working together to provide adaptability and sealing across varying vessel dimensions.
3Device complexity
If single-layer stent structure is used, then device complexity is reduced, but ability to provide both module connection and vessel wall sealing is compromised
Solution Approach 1:
The device uses a nested dual-stent configuration where the inner stent is positioned within the outer stent. This nested structure allows the inner stent to specialize in engaging the prosthetic module while the outer stent specializes in contacting the vessel wall, providing dual functionality without excessive complexity through the efficient use of spatial nesting.
Solution Approach 2:
Despite the dual-stent structure, each stent is designed with universal expandable characteristics using shape memory materials. This allows both stents to adapt to various sizes and configurations, providing multi-functionality for both module connection and vessel wall sealing while maintaining reasonable device complexity through standardized expandable designs.
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 device allows for adjustable radial expansion to accommodate varying vessel and module sizes, ensuring a fluid-tight seal even in areas with aneurysms, enhancing adaptability and sealing efficacy without the need for precise sizing, and utilizing vascular fluid to aid in sealing.
Implementation Method 1
a self-expandable inner stent and a membrane-covered outer stent, where the inner stent can expand radially inwardly to connect modules
Implementation Method 2
the outer stent expands outwardly to abut the vessel wall, providing a fluid-tight seal
Data Source
Figure 1~2
Figure 3~4
AI summary
A coupling device (28) is formed of a double tubing (50) of a substantially non-porous membrane material, typically a conventional graft material, that is of inner and outer layers of membrane material (52, 54). The inner and outer layers (52, 54) are coupled by bridging rings (56, 58) which allow the layers (52, 54) to be spaced from one another in use. Attached to the inner and outer layers (52, 54) are first and second stents (60, 62). The stent (60) is located on the inside of the double tubing, while the stent (62) is located on the outside of the double tubing (50). The device (28) can expand in effect to 'bulge' and thus to fill the gaps to the vessel wall and to the stent-graft sections (24, 26). The device can provide reliable coupling of stent-grafts in vessels of varying diameter or in vessels inflicted with one or more aneurysms.