Composite ePTFE-Silicone Stent Covering for Tissue Ingrowth Prevention
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Solution Overview
Problem
Existing stent-graft technologies face challenges in preventing tissue ingrowth and migration while maintaining structural integrity and ease of removal from bodily lumens, particularly in vascular applications.
Innovation Solution
A medical device comprising a stent with a single expanded polytetrafluoroethylene (ePTFE) layer and an elastomeric layer, such as silicone, applied using methods like spraying or dipping, to enhance biocompatibility and facilitate removal by providing structural reinforcement and preventing further tissue ingrowth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a covered stent is manufactured by placing the stent between two ePTFE sleeves and fusing them together by applying heat and pressure, then the stent-graft structure is formed, but the manufacturing process becomes complex and time-consuming
Solution Approach 1:
The patent extracts one ePTFE sleeve from the traditional two-sleeve construction, using only a single ePTFE layer in conjunction with the stent. This eliminates the need to manufacture, position, and fuse two separate sleeves, thereby simplifying the manufacturing process while maintaining the essential covered stent structure and functionality
Solution Approach 2:
The patent merges the stent and single ePTFE layer into an integrated stent-graft structure. By combining these components in a single manufacturing step rather than assembling multiple separate layers, the process becomes more efficient and less complex while achieving the same structural integrity and protective function
2Reliability
If tissue ingrowth is prevented by using a covered stent, then the stent remains patent, but the device becomes difficult to remove from the lumen
Solution Approach 1:
The patent applies the ePTFE coating selectively to specific regions of the stent rather than covering the entire device. This localized application prevents tissue ingrowth at critical areas while leaving other portions exposed, allowing for controlled tissue interaction that facilitates future removal if needed, thus balancing patency maintenance with removability
3Object-affected harmful factors
If an elastomeric layer is applied to the stent surface, then biocompatibility is enhanced and tissue ingrowth is prevented, but the manufacturing process becomes more complex
Solution Approach 1:
The elastomeric layer is applied to the stent surface before the ePTFE layer is formed. This preliminary application ensures proper adhesion and positioning, eliminating the need for complex post-assembly adjustments or additional bonding steps, thereby reducing overall manufacturing complexity while achieving enhanced biocompatibility and tissue ingrowth prevention
Data Source
AI summary
A medical device consists of a stent having a first surface and a second surface parallel to the first surface; a single expanded polytetrafluoroethylene (ePTFE) layer contacting the first surface of the stent; and an elastomeric layer applied to at least one surface of the stent. In at least one embodiment, the elastomeric layer is silicone. In at least one embodiment, the medical device is manufactured by positioning the ePTFE layer such that a first surface of the ePTFE layer contacts a first surface of the stent to form a stent-ePTFE assembly; and applying an elastomeric solution to the first surface of the ePTFE layer and at least one surface of the stent.