Stent Coating With Preferential Separation for Anti-Migration
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Solution Overview
Problem
Existing stents designed for body lumens face issues with migration due to flexibility and lubricious environments, and difficulty in removal and repositioning due to tissue ingrowth, necessitating a balance between anti-migration and ease of deployment.
Innovation Solution
The stent design incorporates a coating with preferential separation regions and micro-patterns that enhance surface friction while allowing for radial expansion and contraction, reducing migration and facilitating easy removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a stent is designed with sufficient flexibility to assist in delivery, then the stent can be easily deployed, but it has a tendency to migrate from its originally deployed position
Solution Approach 1:
The coating is designed with heterogeneous local properties: anti-migration members (protrusions, ridges, or rough surfaces) are positioned at specific locations such as the ends or segments of the stent to provide anchoring, while other regions maintain smooth surfaces for tissue compatibility. This localized functional differentiation allows the stent to resist migration without compromising overall flexibility and deliverability.
2Reliability
If bare metal portions of the stent are exposed to promote tissue ingrowth and reduce migration, then the stent is anchored in place, but the stent becomes more difficult to remove once deployed
Solution Approach 1:
The stent coating is segmented into distinct functional zones: anti-migration members are confined to specific segments or regions (such as end segments), while other segments retain removable coating properties. This segmentation allows the stent to achieve anchoring through localized tissue interaction while preserving removal capability in other regions.
Solution Approach 2:
The coating is designed with dynamic characteristics that change over time: initially providing strong anti-migration properties through surface friction and mechanical interlocking, then gradually allowing controlled removal or repositioning as needed. The preferential separation region enables the coating to dynamically transition from an anchored state to a removable state.
3Ease of operation
If the thickness and volume of anti-migration coatings are reduced to decrease stent stiffness, then the stent is easier to deploy, but the anti-migration capability is compromised
Solution Approach 1:
The coating is designed as a composite structure combining multiple functional elements: a base coating layer providing structural integrity and flexibility, overlaid with anti-migration members (protrusions, ridges, or rough surfaces) that provide anchoring. This composite design achieves anti-migration capability without requiring thick uniform coating, thus maintaining stent flexibility and ease of deployment.
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
The solution effectively anchors the stent in place, reducing migration risks while maintaining ease of deployment and repositioning, enhancing surface friction through micro-patterns and preferential separation regions.
Implementation Method 1
a preferential separation region, the preferential separation region positioned between a first region of the coating and a second region of the coating. Additionally, the preferential separation region is configured to permit the first region of the coating to separate from the second region of the coating along the preferential separation region therebetween as the expandable scaffold shifts from the radially collapsed state to the radially expanded state
Implementation Method 2
At least a portion of the coating includes a plurality of anti-migration members. The coating further includes a preferential separation region
Data Source
AI summary
A medical device for treating a body lumen, such as a medical stent, includes an expandable scaffold configured to shift from a radially collapsed state to a radially expanded state. The stent includes a coating disposed along the outer surface of the expandable scaffold in which a portion of the coating includes a plurality of anti-migration members and one or more preferential separation regions. Each preferential separation region is configured to permit first and second regions of the coating to separate from one another along the preferential separation region therebetween as the expandable scaffold shifts from the radially collapsed state to the radially expanded state.