Bidirectional Twistable Stent Structure for Tortuous Vessel Navigation
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Solution Overview
Problem
Current self-expanding stents face issues with twisting and bending during navigation to the deployment site, leading to potential collapse, foreshortening, or improper deployment due to their design focusing solely on expansion at the deployment site without considering the stresses of the delivery process.
Innovation Solution
A bidirectional stent design featuring a cylinder-shaped stent body with interconnected rows of struts forming a wave-pattern, utilizing non-flex and flex connectors that allow the stent to twist clockwise or counter-clockwise by a significant angle without deformation, enabling it to navigate complex vascular paths effectively and maintain proper deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If self-expanding stents are designed for expansion at deployment site only, then expansion function is improved, but navigation capability through tortuous vessels deteriorates
Solution Approach 1:
The stent is divided into multiple rows of struts (at least three rows) that are interconnected by flex connectors, creating a segmented structure. This segmentation allows each row to independently accommodate twisting and bending stresses while maintaining overall stent integrity and expansion capability.
Solution Approach 2:
Flex connectors are used to connect adjacent rows of struts, providing flexible joints that allow the stent to twist and bend during navigation. These flex connectors act as flexible elements that accommodate torsional stresses without causing stent collapse or deformation.
2Stability of the object's composition
If stent structure is made rigid for stable expansion, then expansion stability is improved, but resistance to twisting and bending during delivery deteriorates
Solution Approach 1:
Different parts of the stent have different mechanical properties: the struts provide rigidity for stable expansion, while the flex connectors provide flexibility for twisting and bending. This local differentiation of mechanical properties allows the stent to simultaneously achieve expansion stability and delivery flexibility.
Solution Approach 2:
The stent structure transitions from a flexible state during delivery (where flex connectors allow twisting and bending) to a rigid state after deployment (where the expanded struts provide stable support). This dynamic change in structural properties resolves the contradiction between rigidity and flexibility.
3Measurement precision
If stent is constrained on delivery catheter for controlled deployment, then deployment control is improved, but risk of foreshortening and displacement deteriorates
Solution Approach 1:
The stent is pre-formed with a specific wave pattern configuration before delivery. This preliminary structuring ensures that when the stent expands at the deployment site, it does so in a controlled manner that prevents foreshortening and maintains accurate positioning, as the wave pattern is designed to expand radially without axial contraction.
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 bidirectional stent design enhances navigation through tortuous vascular paths, reduces foreshortening, and ensures accurate deployment by allowing rotational twisting without causing deformation, thereby improving the reliability and effectiveness of stent placement.
Implementation Method 1
flex connectors that connect adjacent row sections, wherein each of said flex connectors comprises a first end and a second end... and wherein said stent body is capable of being twisted clockwise or counter-clockwise from one end of said stent body by one-fourth of a turn, or more, without causing deformation of struts and connectors in said stent body
Data Source
AI summary
A bidirectional twistable stent is disclosed. The stent comprises a cylinder-shaped stent body having a plurality of axially arranged rows of struts encircling a central lumen and a plurality of flex connectors that connect at least two adjacent rows of struts in such a manner that allows the stent to be twisted clockwise or counter clockwise without causing deformation of any struts in the stent body. Also disclosed are the method of making the stent, method of using the stent, and a kit containing the stent.