Circumferential Trigger Wire for Stent Deployment
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Solution Overview
Problem
Existing deployment devices for endoluminal prostheses often experience issues with trigger wire entanglement and damage due to crimping and snagging, leading to inaccurate deployment and increased retraction force, particularly when dealing with self-expanding stents and cannula-cut stents with acute bends.
Innovation Solution
A deployment device featuring a circumferential trigger wire system that includes a tubular trigger wire guide with axial and circumferential apertures, allowing the circumferential trigger wire to encircle the prosthesis and engage its end regions, reducing the need for multiple axial trigger wires and minimizing the risk of entanglement and damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple axial trigger wires are threaded through vertices of cannula-cut stents, then the stent can be securely restrained in compressed configuration, but the trigger wires become crimped and entangled with stent struts and barbs, causing damage and increased retraction force
Solution Approach 1:
A circumferential trigger wire is introduced as an intermediary element that encircles the stent and connects to multiple axial trigger wires. This circumferential wire distributes the restraint force evenly around the stent without requiring multiple axial wires to be threaded through acute vertices, thereby preventing crimping and entanglement while maintaining secure restraint
Solution Approach 2:
The trigger wire system transitions from a purely axial configuration to include a circumferential dimension. The circumferential trigger wire wraps around the stent in the circumferential direction, creating a three-dimensional restraint system that eliminates the need for multiple axial wires to pass through problematic vertex regions, thus preventing damage while maintaining restraint security
2Adaptability or versatility
If deployment device is bent to pass through convolutions in anatomical vessel, then the device can navigate complex vasculature, but trigger wires foul or catch with stent components, causing inaccurate deployment or jamming
Solution Approach 1:
The circumferential trigger wire acts as a mediator between the deployment device and the stent, providing a smoother interaction interface. When the deployment device is bent to navigate convolutions, the circumferential wire's configuration reduces the likelihood of triggering wire components catching on stent features, thereby maintaining deployment accuracy while enabling navigation of complex vasculature
3Reliability
If additional trigger wires are added to securely restrain the stent, then the restraint force increases, but the retraction force required to release the stent increases proportionally
Solution Approach 1:
Multiple axial trigger wires are merged into a single circumferential trigger wire system. The circumferential wire encircles the stent and can engage with multiple axial wires or stent features simultaneously, providing secure restraint through a unified structure. This merging reduces the total number of separate trigger wires needed, thereby decreasing the cumulative retraction force required for release while maintaining restraint security
Data Source
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AI summary
A deployment device (100) for deploying an expandable endoluminal prosthesis (200) within a body vessel may include an elongate member extending longitudinally along at least a portion of a length of the deployment device (100). The deployment device (100) may include at least one engagement member coupled to the elongate member and extending outwardly from the elongate member. The deployment device (200) may include a circumferential trigger wire extending at least partially circumferentially around the elongate member and removably received between the engagement member and the elongate member. The circumferential trigger wire may be manipulatable from a distal end of the deployment device (200), whereby the circumferential trigger wire is removable from between the engagement member and the elongate member.