Expandable Stent with Inward Apices for Vessel Flexibility
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Solution Overview
Problem
Existing stents, particularly plastically-deformable and self-expanding stents, face limitations in flexibility and radial strength, making them unsuitable for vessels subject to dynamic loading and high radially-compressive forces, and they often require complex delivery systems that limit access to smaller vasculature.
Innovation Solution
An expandable stent structure with a unique open cell design featuring alternating stiff and flexible portions and inward apices that store and release energy during expansion, allowing for greater flexibility and ease of delivery, while maintaining radial strength and reducing recoil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If plastically-deformable stents are used to provide radial strength, then radial strength is improved, but flexibility deteriorates
Solution Approach 1:
The stent is divided into multiple circumferential rings connected by axial connectors, allowing each segment to independently respond to mechanical loads. This segmentation enables the stent to maintain radial strength through the mesh structure while achieving flexibility through the articulated connections between rings.
Solution Approach 2:
The stent transitions from a static rigid structure to a dynamic articulated structure where circumferential rings can move relative to each other through axial connectors. This dynamic capability allows the stent to adapt to vessel movement and compression forces while maintaining structural integrity and radial support.
2Stability of the object's composition
If plastically-deformable stents are used to ensure structural stability, then structural stability is improved, but ease of delivery deteriorates
Solution Approach 1:
The articulated structure with axial connectors enables the stent to dynamically change its configuration during delivery, allowing it to be compressed onto the delivery balloon and then expanded at the target location. This dynamic capability facilitates ease of delivery while maintaining structural stability in the deployed state.
Solution Approach 2:
The stent's geometric parameters change during delivery and deployment - the circumferential rings can be compressed together during delivery and then expand to their functional configuration at the target site. This parameter transformation enables both ease of delivery and structural stability in the deployed state.
3Strength
If plastically-deformable stents are used to provide radial support, then radial support is improved, but reliability deteriorates
Solution Approach 1:
The dynamic articulated structure allows the stent to absorb and distribute mechanical stresses through movement of circumferential rings relative to each other, preventing stress concentration at any single point. This dynamic stress distribution improves reliability by reducing the risk of fracture and dissection while maintaining radial support.
Solution Approach 2:
The stent combines different material properties within its structure - using plastically-deformable materials for radial support elements while incorporating flexible axial connectors. This composite approach allows the stent to provide radial support where needed while maintaining reliability through flexible connections that prevent fracture.
4Stability of the object's composition
If closed cell stent design is used to ensure structural integrity, then structural integrity is improved, but flexibility deteriorates
Solution Approach 1:
The stent structure segments the continuous mesh into discrete circumferential rings connected by axial connectors. This segmentation maintains structural integrity through the closed-cell-like arrangement within each ring while enabling flexibility through the articulated connections between segments.
Solution Approach 2:
The structure transitions from a rigid closed-cell configuration to a dynamic articulated configuration where circumferential rings can move relative to each other. This dynamic capability provides flexibility while the overall ring structure maintains structural integrity through its closed configuration.
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 open cell stent design enhances flexibility and ease of delivery, enabling treatment of more tortuous anatomy and distal lesions with improved radial strength and reduced risk of fracture or dissection, facilitating better vascular adaptation and treatment outcomes.
Implementation Method 1
Inward apices that store and release energy during expansion
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A
AI summary
An expandable, bistable open cell design incorporates the following features: a first relatively stiff portion (152) having first and second ends and a first relatively flexible portion (154) connected to the first and second ends of the first relatively stiff portion, the first relatively stiff portion and the first relatively flexible portion substantially surrounding a first open area (156) of the stent structure; a second relatively stiff portion (158) having first and second ends and a second relatively flexible portion (160) connected to the first and second ends of the first relatively stiff portion, the first relatively stiff portion and the first relatively flexible portion substantially surrounding a second open area (162) of the stent structure; and an opening (1 10) formed through the first relatively stiff portion and the second relatively flexible portion such that the opening connects the first and second open areas, thereby creating first and second intermediate ends (152a, 152b) of the first relatively stiff portion and first and second intermediate ends (160a, 160b) of the second relatively flexible portion. The first intermediate end (152a) of the relatively stiff portion is connected to the first intermediate end (160a) of the relatively flexible portion so as to create a first inward apex (170), the second intermediate end (152b) of the relatively stiff portion is connected to the second intermediate end (160b) of the relatively flexible portion so as to create a second inward apex (172), and the stent structure is configured such that, in a collapsed configuration, the first inward apex (170) is in contact with the second inward apex (172) and, in an expanded configuration, the first inward apex is biased to move in a first circumferential direction and the second inward apex is biased to move in a second circumferential direction that is different than the first circumferential direction.