Rotatable Outer Sheath for Stent Retention and Deployment
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Solution Overview
Problem
Current drainage stent delivery systems lack effective retention mechanisms for controlled positioning and deployment of stents in body lumens, leading to potential premature deployment issues.
Innovation Solution
A stent retention structure utilizing an outer sheath that can be actuated from a first position to a second position through rotational motion, allowing for secure coupling and decoupling of the stent from the delivery system, enabling controlled deployment and retrieval.
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 retained during delivery, but the mechanism lacks reliability for controlled positioning and deployment
Solution Approach 1:
The outer sheath is designed to be rotatable relative to the stent, transforming a static retention connection into a dynamic one. The retention mechanism transitions from a fixed suture connection to a rotatable engagement system where the sheath can rotate to lock or unlock the stent, providing controlled deployment while maintaining reliability
Solution Approach 2:
The outer sheath acts as an intermediary component between the delivery system and the stent. Instead of directly connecting the stent to the delivery catheter via suture, the sheath mediates the connection through its rotatable engagement, providing a more reliable and controllable retention mechanism
2Ease of operation
If the outer sheath is made slidable over the push catheter for actuation, then controlled deployment is enabled, but the device complexity increases
Solution Approach 1:
The outer sheath combines multiple functions into a single component: it serves as both the retention mechanism (through rotatable engagement with the stent) and the deployment actuator (through slidable movement over the push catheter). This merging reduces the need for separate retention and deployment mechanisms, simplifying the overall device structure while maintaining ease of operation
Solution Approach 2:
The outer sheath is designed as a multi-functional component that performs retention, positioning, and deployment functions. By making the sheath both rotatable for retention and slidable for deployment, the design achieves universality where a single component handles multiple critical operations, improving ease of operation without proportionally increasing complexity
Data Source
AI summary
A drainage stent delivery system including a stent, a guide catheter, a push catheter, and an outer sheath. The guide catheter extends through the lumen of the stent and the push catheter is disposed over a portion of the guide catheter proximal of the distal end of the stent. The outer sheath is slidably disposed over the push catheter and surrounding at least a portion of the stent. The outer sheath may be actuated from a first position in which a distal portion of the outer sheath surrounds the stent to a second position in which the distal portion of the outer sheath is proximal of the stent. The stent delivery system may also include a retention mechanism for selectively coupling the stent to the outer sheath which may selectively decouple the stent from the outer sheath through rotational and/or translational motion of the outer sheath relative to the stent.