Stent Deployment Device with Anti-Backlash Spring
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Solution Overview
Problem
Conventional push-pull delivery devices for self-expanding prostheses lack control and accuracy during deployment, making it difficult to reposition the prosthesis once it has radially expanded and engaged the body lumen.
Innovation Solution
A delivery device featuring a fixed pusher member and a longitudinally-movable outer catheter sheath that allows for the deployment and recapture of an intraluminal prosthesis, enabling precise control and repositioning through a mechanism involving an advancement plate, keeper plate, and trigger mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional push-pull delivery device is used to deploy a self-expanding prosthesis, then the deployment mechanism is simple, but the control and accuracy of placement are poor
Solution Approach 1:
The delivery device is divided into separate functional components: an inner catheter for prosthesis support, an outer catheter for containment and controlled release, and a pusher member for deployment actuation. This segmentation allows each component to perform its specific function independently, improving placement accuracy while maintaining manageable overall complexity
Solution Approach 2:
The outer catheter acts as an intermediary between the operator and the prosthesis, providing a controlled interface for deployment. By manipulating the outer catheter's retraction, the operator can precisely control when and where the prosthesis is released, thereby improving placement accuracy without requiring direct manipulation of the prosthesis itself
2Ease of operation
If the outer catheter is retracted to deploy the prosthesis, then the prosthesis is released, but repositioning becomes difficult or impossible
Solution Approach 1:
The delivery device employs dynamic control where the outer catheter can be retracted to deploy the prosthesis and then re-advanced to recapture it. This dynamic capability allows the system to transition between deployment and repositioning states, enabling easy repositioning while maintaining reliable control throughout the procedure
Solution Approach 2:
The outer catheter temporarily releases the prosthesis during deployment but retains the capability to recapture it by re-advancement. This recoverable containment mechanism allows the operator to correct placement errors by recapturing and repositioning the prosthesis, thereby improving repositioning ease while maintaining deployment control
3Manufacturing precision
If the prosthesis is allowed to radially self-expand, then it engages the body lumen, but incorrect position deployment cannot be corrected
Solution Approach 1:
The outer catheter maintains containment of the prosthesis during navigation and positioning, preventing premature expansion. Only when the prosthesis is correctly positioned does the operator retract the outer catheter to allow expansion. This preliminary containment action ensures precise deployment position while preventing harmful premature engagement with tissue
Solution Approach 2:
The system provides visual and tactile feedback to the operator during the deployment process, allowing real-time assessment of prosthesis position before final release. This feedback mechanism enables the operator to make precise positioning adjustments and prevents incorrect deployment, thereby improving deployment position precision while reducing tissue damage risk
Data Source
Figure 1A~1C
Figure 2A~2B
Figure 3A~3B
AI summary
A delivery device for deploying and resheathing an expandable prosthesis such as a stent. The delivery device includes a movable outer sheath and a fixed pusher/holder member that are configured for the sheath to retract in a proximal direction to release and/or to extend distally to resheath the stent. The device includes a spring-tensioned antibacklash mechanism to accommodate any backlash elongation and/or compression of the pusher/holder member and sheath.