Covered Stent With Uncovered Cell Rows For Flexibility
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Solution Overview
Problem
Current covered stents face challenges in balancing the need to prevent tissue ingrowth and overgrowth while maintaining flexibility to adapt to changes in lumen shape, with fully covered stents being prone to migration and partially covered stents being ineffective at sealing fistulae and losing functionality due to excessive ingrowth.
Innovation Solution
A covered stent design featuring a selected distribution of uncovered cells to enhance flexibility, where at least one circumferential row of cells lacks a membrane covering and is bordered by membrane-covered rows, allowing for increased adaptability and reduced migration risk while maintaining sealing capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fully covered stent is used to prevent tissue ingrowth and overgrowth, then the stent structure becomes more rigid and prone to migration, but the ability to prevent tissue ingrowth is improved
Solution Approach 1:
The stent applies different surface properties to different regions: the distal end has a fully covered surface to prevent tissue ingrowth and overgrowth, while the proximal end has a partially covered surface allowing tissue ingrowth for anchoring. This local differentiation resolves the contradiction by providing both anti-ingurowth capability and flexibility at the appropriate locations.
Solution Approach 2:
The stent surface is segmented into distinct zones: a distal covered portion and a proximal partially covered portion. This segmentation allows each zone to perform its specific function independently, with the covered distal end preventing ingrowth and the uncovered proximal end providing flexibility and anchoring.
2Adaptability or versatility
If a partially covered stent is used to improve flexibility and tissue ingrowth, then the stent can adapt better to lumen changes, but the ability to seal fistulae is reduced
Solution Approach 1:
The stent concentrates the sealing function at the distal end where the fully covered surface creates a barrier to fistula formation, while the proximal end maintains partial coverage for flexibility. This localized functional differentiation resolves the contradiction between sealing capability and adaptability.
3Duration of action of stationary object
If a fully covered stent is used to prevent tissue ingrowth, then the stent remains functional longer, but the stent becomes more rigid and may cause tissue damage
Solution Approach 1:
The stent provides a covered surface at the distal end to prevent tissue ingrowth and maintain long-term functionality, while the uncovered proximal surface allows tissue integration that reduces rigidity and potential tissue damage. This spatial differentiation resolves the contradiction between durability and tissue compatibility.
Data Source
AI summary
A covered stent having a selected arrangement of uncovered cells is provided. The uncovered cells are configured to provide a desired flexibility profile to the stent structure. In one preferred embodiment, the stent contains one or more circumferential rows of uncovered cells located between two or more circumferential rows of covered cells. In some embodiments, the stent may have a central body portion and one or more flanges where the circumferential rows of uncovered cells may be located within the flange(s).