Self-Expanding Polymeric Stent Segmentation for Radial Strength
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Solution Overview
Problem
Conventional medical implants, particularly those made of metallic stents and biodegradable polymers, face limitations such as thrombosis, restenosis, poor expandability, and uncontrolled degradation, as well as challenges in drug elution and mechanical strength, which hinder their effectiveness in treating medical conditions.
Innovation Solution
Development of self-expanding tubular medical devices made from polymeric or metallic strands with a support coating, featuring a therapeutic agent like paclitaxel, designed to expand and maintain strength while delivering a low dose of drug effectively, with improved radial strength and controlled drug release properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If biodegradable and biostable polymeric materials are used for stents, then long-term effects of permanent implants are eliminated, but expandability and mechanical properties deteriorate
Solution Approach 1:
The stent is segmented into multiple struts and cells, allowing the polymeric structure to achieve sufficient mechanical strength through geometric configuration rather than material properties alone. The segmented design enables the stent to expand and provide radial support while using biodegradable materials.
Solution Approach 2:
The invention uses composite polymeric materials that combine biodegradable components with enhanced mechanical properties. The composite structure allows the stent to maintain strength and expandability during the critical period before degradation completes, while ultimately being absorbed by the body.
2Volume of moving object
If low-profile design with small diameter fibers is used, then device profile is reduced, but expansion characteristics and radial strength deteriorate
Solution Approach 1:
The stent is divided into multiple thin struts arranged in a lattice pattern. This segmentation allows each individual strut to remain thin and flexible for low-profile delivery, while the collective arrangement of numerous struts provides sufficient radial strength and expansion characteristics when deployed.
Solution Approach 2:
The stent design transitions from a solid thick-walled structure to a three-dimensional lattice framework. This dimensional change allows the device to maintain a low profile during delivery while achieving adequate radial strength through the spatial arrangement and interconnection of multiple thin struts in three dimensions.
3Reliability
If drug-eluting polymer coatings are added to metallic stents, then restenosis risk is decreased, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The invention merges the structural function of the stent with the drug delivery function into a single integrated polymeric component. Rather than adding a separate coating layer to a metallic stent, the drug-eluting functionality is incorporated directly into the biodegradable polymeric stent material itself, simplifying the overall device structure and manufacturing process.
Data Source
AI summary
Disclosed are self-expanding medical implants for placement within a lumen of a patient. The implants comprise a woven or non-woven structure having a substantially tubular configuration, and are designed to be low-profile such that they are deliverable with a small diameter catheter. The implants have a high recoverability and desired mechanical properties.