Stent Retention Structure for Controlled Delivery
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Solution Overview
Problem
Current drainage stent delivery systems lack effective retention mechanisms for securely and controllably deploying stents in body lumens, leading to potential premature deployment and loss of control during medical procedures.
Innovation Solution
The implementation of an interference fit retention structure between the stent and the elongate shaft of the delivery system, allowing for axial movement to engage and disengage the stent, providing a secure and controlled deployment mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flexible thread or suture is used for releasably connecting the drainage stent to the delivery system, then the stent can be controlled during positioning, but the connection may not provide sufficient security and control against premature deployment
Solution Approach 1:
The retention structure is divided into multiple components: an interference fit member with radial arms, a shaft with corresponding features, and a stent with engagement elements. This segmentation allows each component to contribute specifically to the retention function, providing secure control while maintaining manageable complexity through modular design.
Solution Approach 2:
The interference fit member is positioned within the lumen of the tubular stent, with radial arms extending into the stent lumen. The shaft extends through the interference fit member, creating a nested configuration where smaller components are contained within larger ones, maximizing space utilization and securing the stent to the delivery system.
2Reliability
If the stent is securely retained to the delivery system, then control over positioning is improved, but the mechanism for controlled release becomes more complex
Solution Approach 1:
The retention mechanism transitions from a static secure connection to a dynamic release system. Axial movement of the shaft relative to the stent causes the interference fit member to move from a first position (within the stent lumen providing secure retention) to a second position (exterior of the stent enabling release). This dynamic transformation allows controlled deployment through simple axial motion.
Solution Approach 2:
The interference fit member acts as an intermediary between the shaft and the stent. It provides the retention function when positioned within the stent lumen and facilitates controlled release when moved axially to an exterior position. This intermediary component mediates the transition between secured and released states, simplifying the overall operation.
3Strength
If an interference fit member is positioned within the stent lumen to form an interference fit, then secure attachment is achieved, but the disengagement mechanism requires axial movement which may increase device complexity
Solution Approach 1:
The complex mechanical disengagement mechanism is replaced with a simple axial movement system. The interference fit member and shaft are designed with complementary features that allow straightforward axial motion to transition from engagement to disengagement, eliminating the need for complex levers, springs, or multi-step release mechanisms.
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 solution ensures secure attachment and controlled release of the stent, preventing premature deployment and allowing for precise positioning and retrieval during medical procedures.
Implementation Method 1
an interference fit member positioned on the elongate shaft and configured to cooperate with the tubular stent to form an interference fit therebetween
Data Source
AI summary
A drainage stent delivery system including an elongate shaft of a medial device, a drainage catheter or stent, and an interference fit member for selectively coupling the drainage stent to the elongate shaft. The drainage stent is selectively coupled to a distal portion of the elongate shaft by an interference fit between the interference fit member and the drainage stent such that axial movement of the elongate shaft relative to the drainage stent moves the interference fit member from a first position in which the interference fit member is engaged with the drainage stent and forms an interference fit with the drainage stent to a second position in which the interference fit member is disengaged from the drainage stent.