Stent with Selective Polymeric Coating for Tissue Protection
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Solution Overview
Problem
Existing endoprostheses, such as stents, often cause tissue irritation and fail to maintain patency in body lumens while allowing fluid flow from side branches, lacking anti-migration features and efficient trauma reduction during removal.
Innovation Solution
A medical stent with a tubular support structure featuring struts covered by a polymeric coating, where specific regions are selectively coated to allow fluid flow and reduce irritation, using techniques like spray coating and laser ablation to control the polymeric material distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bare metal stent is used to maintain lumen patency, then structural support and patency are improved, but tissue irritation and trauma increase
Solution Approach 1:
A polymeric coating is applied as an intermediary layer between the bare metal stent and the surrounding tissue. This coating acts as a mediator that reduces direct contact between the metal and tissue, thereby decreasing tissue irritation and trauma while preserving the stent's structural support function for maintaining lumen patency.
Solution Approach 2:
The stent is constructed as a composite structure combining metal struts with polymeric coating material. This composite approach integrates the structural advantages of metal (strength, patency maintenance) with the biocompatibility advantages of polymeric materials (reduced tissue irritation), creating a hybrid device that addresses both requirements.
2Reliability
If the stent structure is made more complex to provide anti-migration features, then stability is improved, but device complexity increases
Solution Approach 1:
The stent incorporates localized features such as flares or expansions at specific positions along the stent length, rather than uniformly complex structures throughout. This local modification provides anti-migration capability where needed while keeping the overall device design relatively simple and manufacturable.
3Strength
If the stent removes all inter-strut spaces for structural integrity, then strength is improved, but fluid flow capability deteriorates
Solution Approach 1:
The stent structure is designed with spatially varying characteristics: certain regions maintain closed cells for structural strength, while other regions incorporate open inter-strut spaces or fenestrations to permit fluid flow. This local differentiation allows simultaneous optimization of both strength and flow capability in different stent zones.
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 reduces tissue irritation, maintains patency, and provides anti-migration features by selectively opening inter-strut spaces for fluid flow, enhancing the stent's performance in maintaining lumen patency and reducing trauma during removal.
Implementation Method 1
using techniques like spray coating and laser ablation to control the polymeric material distribution
Implementation Method 2
using techniques like spray coating and laser ablation to control the polymeric material distribution
Data Source
AI summary
A medical stent may include a tubular support structure including a plurality of struts defining a plurality of cells disposed between the plurality of struts. A polymeric coating may be disposed over the tubular support structure such that a first portion of the plurality of cells are closed by the polymeric coating in a first region of the tubular support structure and a second portion of the plurality of cells in a second region of the tubular support structure remain open to fluid flow and/or tissue ingrowth therethrough. The struts in the first region of the tubular support structure and the struts in the second region of the tubular support structure may be at least partially covered by the polymeric coating.