Expansion Ring for Braided Stent Deployment
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Solution Overview
Problem
Braided stents face challenges in deploying and anchoring within neurovascular vessels due to high internal friction and limited access for expansion ring attachment, making it difficult to open and recapture, especially in tiny vessels like those in the brain, which increases the risk of trauma and rupture.
Innovation Solution
A braided stent system with shape memory configuration expansion rings, including outer and center strut members with a laser-cut clipping pattern, that can be slidably secured to the stent body's inner and outer surfaces, providing an outwardly expanding radial force and allowing for easy deployment and recapture without permanent attachment, using materials like nickel titanium for enhanced flexibility and resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional stent deployment methods are used in neurovascular vessels, then the stent can be deployed to reinforce the vessel wall, but the high internal friction and limited access make it difficult to open and recapture the stent, increasing the risk of trauma and rupture
Solution Approach 1:
The stent is divided into multiple segments or struts that can be independently controlled. The delivery catheter includes multiple control wires that can selectively expand individual stent segments, allowing for controlled deployment and recapture. This segmentation enables the stent to be opened only at the desired location and recaptured if needed, reducing vessel trauma risk.
Solution Approach 2:
The stent transitions from a static compressed state in the delivery catheter to a dynamic expandable state at the target site. The control wires allow the stent to dynamically change its radial dimension, enabling deployment when needed and recapture when necessary, thereby reducing the risk of permanent vessel trauma.
2Force
If expansion rings are added to increase radial expansion force, then the stent can be opened more effectively, but the limited access in tiny vessels makes attachment difficult
Solution Approach 1:
The expansion rings are nested within the delivery catheter in a compact configuration before deployment. The catheter is designed to contain the expansion rings in a collapsed state, allowing them to be delivered through tiny vessels. Upon deployment, the rings expand outward to provide the necessary radial expansion force, eliminating the need for complex external attachment procedures.
Solution Approach 2:
The expansion rings are designed to self-expand upon delivery to the target site. The mechanical structure of the rings includes shape memory or spring-loaded components that automatically expand when released from the catheter, providing radial expansion force without requiring complex external attachment mechanisms or additional manipulation in the constrained vascular environment.
3Strength
If permanent attachment methods are used to secure the expansion ring, then the stent can be firmly anchored, but recapture becomes impossible
Solution Approach 1:
The attachment mechanism transitions from an attached state during deployment to a detached state for recapture. The expansion rings are initially attached to the stent body to provide anchoring strength during expansion, but can be selectively detached to allow recapture of the stent if procedural adjustments are needed, providing both strength and adaptability.
Solution Approach 2:
The attachment elements are designed to be temporarily attached during deployment and then discarded or detached to enable recapture. The attachment mechanism allows for firm anchoring when needed, but can be released to recover the stent for repositioning or removal, providing both secure anchoring and recapture capability.
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 enables reliable, accurate, and minimally invasive deployment of braided stents with reduced risk of injury, facilitating selective reinforcement of neurovascular defects while minimizing trauma to the blood vessel.
Implementation Method 1
The frame may include a shape memory configuration with a diameter larger than available expansion of the stent body. The frame may be operable to impart an outwardly expanding radial force to the stent body.
Data Source
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AI summary
A braided stent system includes an expansion ring attached to internal and external surfaces of a lumen. A frame of the ring may impart an outwardly expanding radial force to the lumen, the frame including a plurality of elongate members joined at a coupling and at first and second intersections opposite the coupling. A clip can extend from the intersections and can be operable to slidably secure the frame to the inner and outer surfaces of the lumen.