Coiled Member Stent Deployment System
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Solution Overview
Problem
Conventional stent deployment systems using trigger wires can cause damage to stents, particularly nickel-titanium stents, 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 the stent is looped around the coiled member's proximal end and disposed between its turns, allowing for controlled deployment without trigger wires, reducing the risk of damage and deployment force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If trigger wires are used to restrain the stent during delivery, then the stent can be securely held in a compressed configuration, but the trigger wires may become crimped at the vertices causing damage to the stent segments
Solution Approach 1:
A coiled member is introduced as an intermediary component between the delivery catheter and the stent. The coiled member engages with the stent at its apex rather than directly at the vertices, serving as a mediator that prevents direct contact and potential damage between the restraint mechanism and the stent's vulnerable segments.
Solution Approach 2:
The restraint mechanism is segmented into distinct functional components: the delivery catheter, the coiled member, and the stent itself. This segmentation allows the coiled member to be positioned specifically at the stent apex, distributing the restraint forces away from the vulnerable vertex regions of the stent segments.
2Ease of operation
If trigger wires are threaded through the vertices of cannula-cut stents, then the stent can be restrained during delivery, but the trigger wires and/or stent segments may become damaged during delivery
Solution Approach 1:
The coiled member acts as an intermediary that eliminates the need to thread wires through the stent vertices. By engaging the stent apex externally, the coiled member prevents direct interaction between trigger wires and the stent surface, thereby avoiding creation of surface imperfections that could compromise stent integrity.
3Force
If multiple trigger wires are provided to reduce deployment force, then the deployment control is improved, but the profile of the delivery system increases
Solution Approach 1:
Multiple restraint functions are merged into a single coiled member structure. The coiled member's spiral configuration allows it to engage with multiple stent apices simultaneously or sequentially, combining the functions of multiple trigger wires into one compact component that maintains a low delivery profile.
Solution Approach 2:
The coiled member is nested within the delivery catheter in a compressed state during delivery, similar to a nested doll structure. This nesting allows the restraint mechanism to be compact during delivery and then expand or uncoil during deployment to provide the necessary restraint and deployment control.
4Volume of moving object
If the stent is compressed to a significantly reduced radial profile, then the delivery profile is minimized, but barbs disposed near the apices may become entangled with the stent struts and/or the trigger wires
Solution Approach 1:
The coiled member serves as an intermediary that prevents direct entanglement between barbs and stent struts during compression. By positioning the engagement point at the apex rather than at the barbed regions, the coiled member mediates the compression forces and keeps barbs separated from the struts, eliminating the entanglement problem.
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 system enables precise and controlled stent deployment with reduced risk of damage and entanglement, minimizing the delivery system's radial profile and deployment force, while ensuring secure engagement and reduced likelihood of failed deployments.
Implementation Method 1
The end of the coiled member that is secured relative to the cannula may be secured using an interference fit
Implementation Method 2
The end of the coiled member that is secured relative to the cannula may be secured using an interference fit, at least one of a solder or weld
Implementation Method 3
The end of the coiled member that is secured relative to the cannula may be secured using an interference fit, at least one of a solder or weld
Implementation Method 4
at least a portion of the distal end of the coiled member securely engages the radial sleeve
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 (30) having an outer surface (31), and at least one coiled member (40) having proximal and distal ends and a plurality of turns disposed therebetween. One of the proximal and distal ends of the coiled member (40) is secured to the outer surface (31) of the cannula (30), and the other of the proximal and distal ends of the coiled member (40) is unsecured relative to the outer surface (31) of the cannula (30). A portion of a stent is looped around the unsecured end of the coiled member (40). Rotation of the cannula (30) causes the portion of the stent to disengage from the coiled member (40). The end of the coiled member (40) that is secured relative to the cannula (30) is secured using at least two securing members.