Coiled Member Stent Deployment via Cannula Rotation
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Solution Overview
Problem
Conventional stent deployment methods using trigger wires can cause damage to stents, especially nickel-titanium ones, and require high deployment forces, leading to entanglement issues and increased delivery system profile.
Innovation Solution
A system employing a coiled member secured to a cannula, where a portion of the stent is looped around the unsecured end of the coiled member, allowing rotation to disengage the stent, reducing the need for trigger wires and minimizing deployment force, with multiple securing methods to prevent failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If trigger wires are used to deploy stents, then stent deployment can be achieved, but stent damage occurs and deployment force is high
Solution Approach 1:
The patent removes trigger wires from the delivery system and replaces them with a coiled member mechanism. The stent is deployed by retracting the delivery catheter while the coiled member maintains engagement with the stent, eliminating the need for trigger wires that cause stent damage during deployment.
Solution Approach 2:
The patent changes the deployment mechanism from a trigger wire-based system to a coiled member-based system. The coiled member's spiral geometry and engagement characteristics differ fundamentally from linear trigger wires, reducing stress concentration and damage to the stent during the deployment process.
2Reliability
If multiple trigger wires are used for stent deployment, then deployment control is improved, but delivery system profile increases
Solution Approach 1:
The patent consolidates multiple trigger wire functions into a single coiled member. The coiled member's spiral structure provides continuous engagement with the stent throughout deployment, combining the functions of multiple discrete trigger wires into one integrated component, thereby reducing the delivery system profile.
Solution Approach 2:
The coiled member serves multiple functions simultaneously: it engages the stent, controls deployment, and maintains positioning. This multi-functional design replaces what would traditionally require multiple separate trigger wires, reducing overall system complexity and profile.
3Volume of moving object
If trigger wires are used with acute bend stents, then stent compression is achieved, but wire crimping and entanglement occur
Solution Approach 1:
The coiled member acts as an intermediary between the delivery catheter and the stent. Its spiral geometry allows it to navigate acute bends in the stent without crimping, as the coiled structure can flex and conform to the stent's geometry while maintaining secure engagement.
Solution Approach 2:
The coiled member's curved, spiral geometry is inherently more adaptable to acute bends in the stent compared to linear trigger wires. The curved structure distributes stress along its length and can conform to the stent's bent configuration without creating stress concentration points that lead to crimping or entanglement.
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
This method reduces the risk of stent damage, lowers deployment force requirements, and decreases the delivery system's radial profile, enabling more precise and reliable stent deployment.
Implementation Method 1
a coiled member having proximal and distal ends and a plurality of turns disposed therebetween. One of the proximal and distal ends of the coiled member is secured to the outer surface of the cannula, and the other of the proximal and distal ends of the coiled member is unsecured relative to the outer surface of the cannula
Implementation Method 2
In a stent made of a shape-memory alloy such as nitinol, the shape-memory alloy may be employed to cause the stent to return to a predetermined configuration upon removal of the sheath or other device maintaining the stent in its predeployment configuration
Data Source
AI summary
The present embodiments provide systems and methods for deploying at least a portion of a stent. In one embodiment, the system comprises a cannula having an outer surface, and at least one coiled member having proximal and distal ends and a plurality of turns disposed therebetween. One of the proximal and distal ends of the coiled member is secured to the outer surface of the cannula, and the other of the proximal and distal ends of the coiled member is unsecured relative to the outer surface of the cannula. A portion of a stent is looped around the unsecured end of the coiled member. Rotation of the cannula causes the portion of the stent to disengage from the coiled member. The end of the coiled member that is secured relative to the cannula is secured using at least two securing members.