Stent Strain-Concentration Modules for Shape Recovery
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Solution Overview
Problem
Existing endovascular stents face challenges in maintaining their original shape during radial compression and expansion, leading to potential plastic deformation and reduced effectiveness in treating aortic aneurysms due to inadequate stress distribution.
Innovation Solution
The stent design incorporates strain-concentration modules with open loop, primary neck, and secondary sections, which distribute strain across three phases of compression, preventing plastic deformation by accumulating stress in specific junctions and allowing self-expansion upon deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the stent is highly compressed to provide a reduced crossing profile for percutaneous delivery, then the deliverability and crossing profile are improved, but the stent may undergo plastic deformation and fail to return to its original shape
Solution Approach 1:
The stent is divided into multiple circumferential bands with distinct strain-concentration modules. Each module contains open loop sections, primary neck sections, and secondary sections that independently manage strain during compression. This segmentation allows different portions of the stent to distribute and manage compression stresses separately, preventing concentrated plastic deformation while enabling high compression ratios for reduced crossing profile.
Solution Approach 2:
Specific regions of the stent are designed with unique geometric features (open loop sections with specific width ratios, primary and secondary neck sections with defined segment lengths and angles) that concentrate strain in controlled locations. These local structural variations create predetermined strain distribution patterns that protect critical areas from plastic deformation while allowing overall high compression.
2Ease of manufacture
If the stent structure is simplified for easier manufacture, then the manufacturing complexity is reduced, but the ability to distribute strain effectively during compression is compromised
Solution Approach 1:
The stent is constructed from multiple identical or similar circumferential bands, each containing standardized strain-concentration modules. This repetitive modular design maintains manufacturing simplicity through standardization while achieving complex strain distribution across the entire stent structure. Each band can be manufactured using the same processes, reducing complexity despite the sophisticated strain management requirements.
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
This design ensures the stent returns to its original shape upon expansion, providing a reduced crossing profile for percutaneous delivery and effective treatment of aortic aneurysms by distributing strain effectively during compression.
Implementation Method 1
the resulting strain on the stent is accumulated in at least three phases of the compression at different locations of the strain-concentration modules. Such distribution of stress helps prevent plastic (non-elastic) deformation of the stent
Data Source
AI summary
A stent (120) has proximal and distal ends (140,142), and is configured to assume radially-compressed and radially-expanded states. The stent (120) comprises a plurality of circumferential bands (122) disposed about a longitudinal axis (123) of the stent (120), each of which bands (122) comprises a plurality of struts (124) connected to one another. At least one of the bands (122) is shaped so as to define a plurality of distally-directed peaks (126) alternating with a plurality of proximally-directed troughs (128), and one or more strain-concentration modules (132). Each of the modules (132) has a central axis (156) parallel to the longitudinal axis (123) of the stent (120), and comprises: (a) an open loop section (150), which comprises one of the distally-directed peaks (126); (b) a primary neck section (152); and (c) a secondary section (154). Other embodiments are also described.