Biodegradable Stent Bulbous Geometry Radial Strength
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Solution Overview
Problem
Biodegradable stents face challenges in achieving optimal expansion and integration with vascular walls due to limitations in surface geometry and material properties, which affect their mechanical strength and drug delivery capabilities.
Innovation Solution
A biodegradable stent prosthesis with a tubular expandable body featuring bulbous regions on its structural elements, treated to have convex side surfaces and concave abluminal surfaces, enhancing mechanical strength and drug delivery by redistributing polymeric material without significant weight loss, and utilizing biodegradable polymers like polylactide and copolymers for improved properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If biodegradable stents use conventional cylindrical structural elements, then manufacturing is simple, but radial strength and vascular wall integration are insufficient
Solution Approach 1:
The patent applies curvature by transitioning from conventional cylindrical stent structural elements to bulbous or dogbone-shaped elements with convex sides and concave ends. This geometric modification increases radial strength by distributing stresses more effectively across the curved surfaces while maintaining compatibility with standard cylindrical manufacturing processes through controlled material redistribution during expansion.
2Reliability
If biodegradable stents use uniform surface geometry, then manufacturing is straightforward, but drug delivery performance is limited
Solution Approach 1:
The patent implements local quality by creating distinct surface regions on stent structural elements: convex side surfaces and concave end surfaces. These localized geometric variations are achieved through controlled material redistribution during expansion, allowing enhanced drug delivery at specific locations (concave regions that contact vascular walls) while maintaining overall structural integrity, all through modifications to the expansion process rather than complex multi-step fabrication.
3Reliability
If biodegradable stents are expanded to achieve optimal fit, then vascular wall integration improves, but material strength may be compromised
Solution Approach 1:
The bulbous geometry with convex sides and concave ends distributes expansion stresses more uniformly across the structural elements, preventing stress concentration at sharp corners or flat surfaces. The curved surfaces naturally redirect forces during expansion, allowing the stent to achieve optimal vascular wall integration while maintaining structural integrity throughout the expansion process and during subsequent degradation.
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 stent achieves enhanced radial strength, improved drug delivery, and better integration with vascular walls, maintaining structural integrity and efficacy during expansion and degradation.
Implementation Method 1
treated to provide substantially convex side surface regions and substantially concave abluminal surface regions
Implementation Method 2
Biodegradable scaffolds are usually formed from polymers which degrade by various mechanisms such as by hydrolysis and other reaction mechanisms in the vascular or other body environment
Data Source
AI summary
A biodegradable stent prosthesis formed from a degradable material, having a plurality of luminal, abluminal, and side surface regions, wherein a surface portion extending between the abluminal and luminal surface region of at least some structural elements is convex or bulbous and optionally, where at least some of the abluminal surface regions may be concave.