Segmented Polymeric Covering for Flexible Self-Expanding Stents
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Solution Overview
Problem
Current coated self-expanding stents lack the longitudinal flexibility of their bare counterparts, which can hinder delivery and anatomical modeling, especially in tortuous regions, and may block adjacent lumens, while attempts to improve flexibility through coating thinning compromise durability and leak resistance.
Innovation Solution
An endoprosthesis design featuring a self-expanding framework with a covering of polymeric segments that are fixedly attached and longitudinally spaced in the delivery configuration, overlapping in the deployed configuration to maintain flexibility and prevent blockage, while allowing for side branch access and effective leak resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a continuous coating is applied to the stent, then leak resistance and durability are improved, but longitudinal flexibility is reduced
Solution Approach 1:
The continuous coating is divided into multiple discrete polymeric cover segments that are attached to the stent framework. These segments are spaced apart from one another, creating gaps that allow the stent to flex longitudinally while still providing coverage where needed. The segmented structure maintains durability and leak resistance at the covered portions while restoring flexibility through the gaps between segments.
2Ease of operation
If the coating is thinned to improve flexibility, then longitudinal flexibility is improved, but coating durability and leak resistance are reduced
Solution Approach 1:
Rather than thinning the coating material itself, the invention segments the coating into discrete polymeric cover segments. This allows the coating material to maintain its full thickness and durability properties in the covered regions, while the gaps between segments provide the necessary flexibility. The segments can be made from durable polymeric materials without compromising overall flexibility.
3Reliability
If a coated stent is placed in a primary lumen, then leak resistance is improved, but side branch access is blocked
Solution Approach 1:
The segmented polymeric cover segments create gaps between them that allow access to side branches while maintaining leak resistance in the primary lumen. The segments are positioned and sized to provide coverage where leak prevention is critical while leaving gaps that permit catheter or wire access to intersecting lumens. This selective coverage approach maintains both leak resistance and side branch accessibility.
Data Source
AI summary
An endoprosthesis may include an expandable framework configured to shift between a delivery configuration and a deployed configuration, and a covering including a plurality of polymeric cover segments disposed about at least a portion of the expandable framework. A portion of each of the plurality of polymeric cover segments may be fixedly attached to the expandable framework. The plurality of polymeric cover segments is longitudinally spaced apart from each other in the delivery configuration. The plurality of polymeric cover segments longitudinally overlaps each other in the deployed configuration.