Braided Stent Delivery System with Segmented Support
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Solution Overview
Problem
Braided stents experience significant shortening during deployment, making precise positioning in blood vessels challenging, especially in small braid angles, leading to difficulties in positioning close to organs or cerebral arteries and limited repositioning capabilities in existing delivery systems.
Innovation Solution
The stent support is made separate from the inner sleeve, allowing for relative movement between the outer sleeve and inner sleeve, enabling precise control over stent deployment and positioning through alternate movements of both components, reducing the risk of stent shortening and allowing for repositioning of the braided stent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a braided stent is used with a small braid angle to achieve compact storage and high radial strength, then the stent undergoes significant shortening during deployment, but this makes precise positioning in blood vessels challenging
Solution Approach 1:
The delivery system is segmented into separate functional components: an outer sleeve for stent storage, an inner sleeve for controlled deployment, and a stent support structure. This segmentation allows independent control of each component to manage the shortening effect and achieve precise positioning.
Solution Approach 2:
A stent support structure acts as an intermediary between the inner sleeve and the braided stent. This intermediary component provides a stable platform for stent deployment, allowing the stent to be released in a controlled manner while maintaining positioning accuracy despite the shortening that occurs during expansion.
2Device complexity
If the stent support is integrated with the inner sleeve, then the device structure is simplified, but repositioning capabilities are limited
Solution Approach 1:
The stent support is separated from the inner sleeve into an independent component. This segmentation allows the stent support to move relative to the inner sleeve, enabling the stent to be deployed, held in position, or repositioned as needed without being constrained by the inner sleeve's position.
Solution Approach 2:
The stent support is designed to be dynamically movable relative to the inner sleeve along the delivery system's long axis. This dynamic capability allows the operator to adjust the stent's position before and during deployment, providing versatility in positioning while maintaining a relatively simple overall device structure.
3Device complexity
If the tip is securely connected to the stent support, then the stent release mechanism is simplified, but the length of release is increased
Solution Approach 1:
The tip is extracted from the stent support connection and repositioned to protrude from the outer sleeve's distal end. This extraction allows the stent to be released more efficiently, reducing the length of release required while maintaining the simplicity of the release mechanism through the secure tip-stent support connection.
Data Source
AI summary
An insertion system with a self-expanding braided stent (11) for implantation in a blood vessel has an outer sleeve (12) with a distal end (14) and a proximal end. An inner sleeve (16) arranged in the outer sleeve (12) is displaceable relative to the latter and protrudes, with a handling section, from the proximal end of the outer sleeve (12). Moreover, at the distal end (15), there is a tip (18) which is securely connected to a stent support (24) on which the braided stent (11) is arranged in its loaded state. The stent support (24) is arranged to be displaceable relative to the inner sleeve (16).