Stent Delivery Coupling Assembly Projections
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Solution Overview
Problem
Conventional stent delivery systems face challenges in securely engaging and moving stents of varying sizes within a given catheter size, requiring multiple pad diameters and complex friction fits, which can lead to stent distortion and limited compatibility.
Innovation Solution
A stent delivery system featuring a coupling assembly with a rigid plate or sprocket stent engagement member having projections separated by recesses, which securely engages stents of different sizes within a single catheter size by mechanically interlocking with the stent's pores, allowing for both distal and proximal movement without distally-directed force transmission during delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional friction-fit engagement is used to secure stents of varying sizes, then multiple pad diameters are required, but device complexity increases
Solution Approach 1:
The coupling assembly is designed with a universal engagement mechanism that can accommodate stents of different sizes using a single pad diameter. The engagement member features a circumferential engagement surface with multiple engagement zones that can interface with stents ranging from 4mm to 7mm in diameter, eliminating the need for multiple specialized pads for different stent sizes.
Solution Approach 2:
The coupling assembly incorporates a compliant engagement surface that can dynamically adapt to different stent diameters and configurations. The engagement member includes flexible elements that deform to match the contours of various stent designs, allowing a single pad design to securely engage multiple stent sizes through dynamic adjustment rather than requiring multiple fixed-diameter pads.
2Ease of operation
If conventional friction-fit engagement is used to move stents, then stent distortion occurs, but this is an unavoidable side effect
Solution Approach 1:
The engagement surface is segmented into multiple discrete engagement zones distributed circumferentially around the coupling assembly. These segmented contact points distribute the engagement forces across multiple locations on the stent, preventing concentration of stress at single points and thereby reducing stent distortion while maintaining the ability to move the stent distally and proximally.
Solution Approach 2:
The coupling assembly employs a flexible engagement surface that can conform to the stent geometry without imposing rigid constraints. This flexible interface allows the stent to maintain its natural shape during delivery and movement, reducing distortion while still enabling controlled distal and proximal motion through the delivery catheter.
3Reliability
If rigid engagement is used to secure stents, then stent distortion increases, but secure engagement is compromised
Solution Approach 1:
The coupling assembly utilizes controlled parameter changes in the engagement interface, transitioning from rigid to compliant contact characteristics. The engagement member incorporates materials and structures that provide appropriate compliance under load, changing the mechanical parameters of the interface to maintain secure engagement while accommodating stent geometry and minimizing distortion.
Data Source
AI summary
A stent delivery system includes a core member and a coupling assembly rotatably coupled to the core member distal segment. The coupling assembly includes first and second plates and first and second spacers. The first plate is rotatably coupled to the core member and includes an outer surface having three or more projections separated by recesses. The first spacer is coupled to the core member and disposed between the first plate and a proximal restraint. The second plate is rotatably coupled to the core member and includes an outer surface having three or more projections separated by recesses. The second spacer is coupled to the core member and disposed between the first plate and the second plate. A stent extends along the core member distal segment such that an inner surface of the stent is engaged by one or more projections of the first plate or the second plate.