Stent Delivery System Locking Mechanism for Proximal Loop Control
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Solution Overview
Problem
Existing delivery systems for self-expanding stents often face issues with the proximal end getting caught in the vessel wall during withdrawal, and there is a risk of the stent twisting due to inadequate release mechanisms, leading to incomplete deployment or damage.
Innovation Solution
A delivery system with an outer tube and inner tube that move axially, featuring a locking system with pin elements and engagement units to securely hold and release the proximal end's projecting loops, preventing jamming and rotation, allowing for accurate positioning and expansion of the stent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the proximal end of the stent is compressed and held by the delivery system for introduction into the vessel, then the stent can be introduced in a compressed state, but the projecting loops may become caught in the vessel wall during withdrawal
Solution Approach 1:
The delivery system is divided into two separate tubes: an outer tube that holds the stent in compressed state and an inner tube that specifically controls the proximal end with pin elements. This segmentation allows independent control of the proximal end release, preventing it from being caught in the vessel wall during withdrawal while maintaining the compressed state for introduction.
Solution Approach 2:
Pin elements are introduced as intermediary components that engage with the projecting loops of the proximal end. These pin elements act as mediators between the inner tube and the stent's proximal end, providing secure holding during introduction and controlled release during deployment, preventing the loops from becoming caught in the vessel wall.
2Device complexity
If the stent is held in place by a simple delivery system, then the device complexity is reduced, but the stent may rotate or twist during deployment
Solution Approach 1:
The delivery system uses segmented control with separate inner and outer tubes, where the inner tube with pin elements specifically controls the proximal end orientation. This segmentation provides rotational stability without requiring a completely complex integrated system, as only the critical proximal end needs precise control.
Solution Approach 2:
The pin elements provide localized control and stabilization at the proximal end of the stent, where orientation control is most critical. This local quality approach stabilizes the stent's orientation at the key deployment point without adding complexity to the entire delivery system structure.
3Device complexity
If the proximal end is released without a locking mechanism, then the release process is simpler, but the projecting loops may jam or become caught
Solution Approach 1:
The locking system is segmented into discrete pin elements that individually engage with each projecting loop. This segmentation allows for controlled, sequential release of the proximal end, ensuring complete and jam-free release without requiring a complex integrated locking mechanism.
Solution Approach 2:
The pin elements are designed to automatically engage with the projecting loops during assembly and automatically disengage during the release process when the inner tube is withdrawn. This self-service mechanism ensures reliable complete release without requiring complex external locking or unlocking operations.
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
Ensures safe and complete release of the stent's proximal end without jamming, prevents stent rotation, and allows for correct positioning by locking the loops with pin elements, ensuring the stent expands correctly and anchors securely in the vessel wall.
Implementation Method 1
a locking system (16) for the projecting loops (36) at the proximal end (32) of the stent (30) for introduction of the stent (30) into the body vessel (2), the locking system (16) having a cap element (18) with pin elements (20, 22) fixed to it
Implementation Method 2
an inner tube (14) which passes through the outer tube (12), the inner tube (14) and the outer tube (12) being designed to move axially with respect to one another
Implementation Method 3
self-expanding stent systems which are introduced into the vessel in a compressed state and which are allowed to expand by removal of compressive structures
Data Source
AI summary
The present invention relates to a delivery system for a self-expanding stent with a hollow cylindrical body and a proximal and a distal end. At least the proximal end thereof has projecting loops pointing alternately in the proximal and distal direction, the loops having a shoulder and straight sections. In addition, there is an outer tube which passes through the stent and an inner tube which passes through the outer tube, the inner tube and the outer tube being designed to move axially with respect to one another. In addition, it is fitted with a locking system for the projecting loops at the proximal end of the stent for introduction of the stent into the body vessel, the locking system having a cap element with pin elements fixed to it which point axially in the proximal direction of the delivery system and a first engagement unit for the pin elements which is positioned proximal with respect to the cap element in the delivery system.