Stent Delivery Interface With Patterned Pusher Recesses for Clean Release
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Solution Overview
Problem
Existing delivery devices face challenges in efficiently decoupling stents from pushers due to excessive coupling force, leading to temporary sticking and inefficient deployment.
Innovation Solution
A method involving the creation of recesses in an implant engagement member to match the pattern of the stent's sidewall, allowing for efficient decoupling and deployment by using a harder material with grooves that accommodate the stent components, enabling a larger expansion force than the frictional force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the coupling force between the pusher and the stent is increased to ensure secure delivery, then the stent can be delivered reliably, but the stent may stick to the pusher after deployment and fail to decouple efficiently
Solution Approach 1:
The pusher is designed with a patterned surface featuring recesses, protrusions, or grooves that locally match the stent's surface pattern. This creates localized engagement zones with optimized coupling characteristics - sufficient grip for delivery but controlled friction for easy decoupling after deployment
Solution Approach 2:
The coupling interface between pusher and stent is designed with asymmetric characteristics - the patterned surface creates directional engagement that provides strong coupling during delivery but allows asymmetric release where the stent can decouple smoothly after expansion
2Ease of operation
If a smooth surface is used on the pusher to reduce friction, then decoupling is easier, but the coupling force becomes insufficient for reliable delivery
Solution Approach 1:
Instead of a uniformly smooth or rough surface, the pusher employs a patterned surface with localized features (recesses, protrusions, grooves) that create optimal coupling zones. These localized patterns provide sufficient friction for delivery while maintaining overall low friction for easy decoupling
3Strength
If the pusher material is made harder to maintain structural integrity, then the pusher can withstand delivery forces, but the frictional force increases causing the stent to stick
Solution Approach 1:
The pusher material properties are optimized by selecting materials with appropriate hardness ranges (e.g., durometer 60A-90A for elastomers) and applying surface treatments or patterns that modify the effective friction coefficient, achieving both structural integrity and controlled friction
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 immediate and efficient decoupling of the stent from the pusher, allowing for smooth deployment and repositioning capabilities without temporary sticking, enhancing the delivery process.
Implementation Method 1
heating the implant engagement member
Implementation Method 2
after the recesses are created in the surface of the implant engagement member, hardening the implant engagement member
Data Source
AI summary
A method of assembling an apparatus for delivering an implant to a deployment site in a patient's vasculature, includes: positioning an implant engagement member at least partially within a lumen of a tubular structure, the tubular structure having a sidewall comprising a pattern of wires or struts; heating the implant engagement member; pressing at least a portion of the sidewall of the tubular structure radially inward into a surface of the implant engagement member so that the wires or the struts of the sidewall penetrate into the surface and create corresponding recesses therein; and after the recesses are created in the surface of the implant engagement member, hardening the implant engagement member.