Stent Retaining Member With Axial Slots For Wire-Free Deployment

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Solution Overview

Problem

Existing stent deployment systems face issues with trigger wires becoming crimped or damaged during compression and deployment, requiring high deployment forces and increasing the delivery system profile, especially for nickel-titanium stents with acute bends.

Innovation Solution

A retaining member with circumferentially enclosed slots and axial openings is used to secure and deploy a portion of the stent, allowing self-expansion without trigger wires, reducing the radial profile and deployment force, and facilitating precise positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If trigger wires are used to restrain stent segments during delivery, then the stent can be compressed to a reduced delivery profile, but the trigger wires may become crimped or damaged during compression and deployment

Engineering Contradiction:

Improvedelivery profileVSAvoidtrigger wire integrity

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The patent removes trigger wires from the system entirely, replacing them with a retaining member that has slots through which stent struts pass. This extraction eliminates the crimping and damage issues associated with trigger wires while maintaining the ability to restrain the stent during delivery.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The retaining member acts as an intermediary structure between the delivery catheter and the stent. Instead of using trigger wires that directly contact and potentially damage stent vertices, the retaining member provides a structured interface with slots that guide and protect the stent struts during compression and deployment.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If multiple trigger wires are used to secure the stent, then the stent can be reliably restrained, but the delivery system profile increases

Engineering Contradiction:

Improvestent restraintVSAvoiddelivery system profile

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent combines multiple restraint functions into a single retaining member structure. Instead of using multiple separate trigger wires that would increase the delivery profile, one retaining member with multiple slots provides equivalent or superior restraint while maintaining a compact delivery system.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The retaining member serves multiple functions simultaneously: it restrains multiple stent struts, provides a structured interface for controlled deployment, and maintains delivery system compactness. This multi-functionality replaces what would otherwise require multiple trigger wires.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Volume of moving object

If trigger wires are threaded through stent vertices with acute bends, then the stent can be compressed to a reduced profile, but the trigger wires and stent segments may become damaged

Engineering Contradiction:

Improvedelivery profileVSAvoidsurface imperfections and damage

Core Design Contradiction:

Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent acknowledges that acute bends in stent vertices create vulnerable points for damage, but instead of avoiding these features, the retaining member is designed to work with them. The slots are configured to receive and protect the struts at these acute bend locations, converting the potential harm into a controlled interaction that preserves stent integrity.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

4Ease of operation

If high deployment force is applied to retract trigger wires, then the stent can be deployed, but the complexity and force requirements increase

Engineering Contradiction:

Improvedeployment operationVSAvoiddeployment force

Core Design Contradiction:

Ease of operationVSForce

Solution Approach 1:

The retaining member is designed with dynamic characteristics that allow for controlled deployment. The slots and stent strut interactions are configured to provide progressive release, reducing the peak force required compared to the sudden release associated with trigger wire retraction. This dynamic design makes the deployment operation easier and safer.

Inventive Principle:

Principle #15Dynamics

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 controlled and precise deployment of stents with reduced deployment force and profile, minimizing damage to stent and trigger wires, and allowing for more accurate positioning at the target site.

Implementation Method 1

A portion of a self-expandable stent is restrained from moving radially outward when disposed within the circumferentially enclosed segment and is self-expandable radially outward when aligned with the axial opening

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS10695205B2Systems and methods for securing and releasing a portion of a stent

Publication Date: 2020.06.30 COOK MEDICAL TECHNOLOGIES LLC

AI summary

The present embodiments provide systems and methods for deploying at least a portion of a stent, comprising a retaining member having a main body. At least one slot is formed into the main body. The at least one slot comprises a circumferentially enclosed segment and an axial opening. A portion of a stent is restrained from moving radially outward when disposed within the circumferentially enclosed segment, and the portion of the stent is self-expandable radially outward when aligned with the axial opening.