Helical-Turn Implant Stent With Connector-Controlled Flexibility
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Solution Overview
Problem
Existing covered stents lack sufficient flexibility, limiting their application in tortuous vessels, particularly for treating peripheral artery disease (PAD) due to interference between adjacent helical turns during bending.
Innovation Solution
A base stent design with helical turns connected by connectors forming a zig-zag pattern, where the shape defined by inner apices and connectors creates a hexagonal or diamond configuration, allowing for greater flexibility by constraining movement at connectors and enabling larger relative movement between adjacent turns, and optionally covered with biocompatible materials like ePTFE, PET, or PU.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If covered stents are made with traditional helical turn designs, then structural stability is maintained, but flexibility is insufficient for tortuous vessels
Solution Approach 1:
The stent structure is divided into multiple helical turns connected by connectors, where each helical turn can move relative to others. The connectors are positioned to allow controlled movement while maintaining overall structural integrity, enabling the stent to flex in tortuous vessels without compromising stability.
Solution Approach 2:
The stent design incorporates dynamic characteristics by allowing adjacent helical turns to move relative to each other through the connector mechanism. This dynamic capability enables the stent to adapt to varying vessel geometries while maintaining structural coherence through the constrained movement at connector positions.
2Adaptability or versatility
If helical turns are allowed to move freely to increase flexibility, then adaptability to tortuous vessels improves, but strut interference occurs reducing flexibility
Solution Approach 1:
The harmful interference between struts is eliminated by extracting the constraint function to specific locations (connectors) rather than having continuous constraints. This allows struts to move freely in non-critical areas while maintaining controlled movement where needed, preventing interference without sacrificing flexibility.
Solution Approach 2:
Connectors serve as intermediary elements between adjacent helical turns, mediating the interaction between struts. These connectors allow controlled relative movement while preventing direct strut-to-strut interference, thus maintaining flexibility without the harmful effects of uncontrolled movement.
Data Source
Figure 1~2b
Figure 3
Figure 4a~6b
AI summary
The present invention relates to an implant, comprising a base stent having a tubular shape and surrounding a lumen, the base stent comprising a first section having helical turns, wherein adjacent helical turns are connected to each other by connectors that extend between adjacent helical turns and that limit movement of the adjacent helical turns relative to each other, wherein the helical turns comprise struts that are connected in a zig-zag pattern, with individual struts being connected at apices, wherein the shape that is defined by the inner apices of two axially adjacent helical turns and by two connectors that are adjacent to one another has, in the unconstrained state of the implant, at a position between the two connectors delimiting it, a longer first axial dimension than a second axial dimensions at the positions of the two connectors.