Variable Strut Stent with Sigmoidal Bridges for Vessel Flexibility
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Solution Overview
Problem
Current stents, especially longer ones, face challenges with flexibility when delivered through torturous vessels, which can lead to deployment issues and increased risk of fracture or kinking, while also having potential gaps with the vessel wall that may cause thrombosis due to mismatched diameters.
Innovation Solution
The design incorporates variable strut lengths and sigmoidal shaped bridge members to enhance axial flexibility and maintain scaffolding ability, with features like strain relief regions, arcuate surfaces, and elastomeric materials to improve stent flexibility and stability during deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If longer stents are used to treat long diffuse lesions, then the treatment coverage is improved, but the flexibility and deliverability through torturous vessels deteriorates
Solution Approach 1:
The stent is divided into multiple tubular rings connected by bridges, creating segmented structures that can flex relative to each other. This segmentation allows the long stent to navigate torturous vessels while maintaining overall length for treating diffuse lesions.
Solution Approach 2:
The stent incorporates variable bridge lengths and articulation points that allow dynamic adjustment of the stent configuration during delivery and deployment, enabling it to adapt to vessel tortuosity while maintaining structural integrity.
2Strength
If tubular rings are kept close together to provide maximum scaffolding, then the scaffolding ability is improved, but the axial flexibility deteriorates
Solution Approach 1:
The stent structure segments the connection between tubular rings into discrete bridge elements of varying lengths, allowing close spacing of rings for scaffolding while maintaining flexibility through the bridged connections.
Solution Approach 2:
Different regions of the stent have different bridge lengths and configurations, with longer bridges in regions requiring flexibility and shorter bridges where scaffolding density is prioritized, allowing local optimization of both properties.
3Ease of operation
If fewer bridges are used to increase flexibility, then the axial flexibility is improved, but the stent column strength deteriorates
Solution Approach 1:
The stent employs variable bridge lengths where longer bridges provide flexibility in specific segments while shorter bridges or alternative structural features maintain column strength in critical regions, optimizing both properties locally.
Solution Approach 2:
The bridge structures incorporate articulation and variable geometry that allows them to flex under axial loads while maintaining structural integrity, providing flexibility without sacrificing column strength.
4Adaptability or versatility
If self-expanding stents are used to conform to varying vessel diameters, then the adaptability to vessel geometry is improved, but the risk of thrombosis formation may increase due to potential gaps
Solution Approach 1:
The variable strut lengths within tubular rings create localized density variations that allow the stent to conform to vessel diameter changes while maintaining adequate radial support to prevent gap formation and thrombosis.
Solution Approach 2:
The self-expanding mechanism with variable geometry allows the stent to dynamically adapt to vessel diameter variations, maintaining continuous contact with the vessel wall to prevent thrombosis while accommodating tortuosity and taper.
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 solution allows for improved flexibility and reduced risk of thrombosis by maintaining scaffolding strength and reducing deployment issues, such as twisting or buckling, while accommodating varying vessel diameters.
Implementation Method 1
The bridge members may be made of an elastomeric material
Implementation Method 2
sigmoidal shaped bridge members to enhance axial flexibility and maintain scaffolding ability, with features like strain relief regions
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
A tubular prosthesis has a plurality of tubular rings that are radially expandable from a contracted configuration to an expanded configuration. Each ring comprises a plurality of axially oriented struts that are interconnected so as to form a circumferential series of at least one high peak and at least one low peak. The high and low peaks have apices that are oriented in the same axial direction. The apices of the high and low peaks are also oriented in the same direction and the apices of the high peaks are axially offset from the apices of the low peaks. A bridge member couples a pair of adjacent tubular rings together. The bridge member has a first end connected to a first low peak in a first tubular ring and a second end connected to either a high or low peak in an adjacent tubular ring.