Stent with Offset Connecting Elements for Fracture Resistance
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Solution Overview
Problem
Medical devices placed in body lumens often face challenges in fracture resistance and stress concentration under compressive loading, and existing solutions do not effectively minimize thrombosis and intimal hyperplasia in blood vessels.
Innovation Solution
A medical device with a three-dimensional curved shape that transitions from a straight, cylindrical configuration to a helically or spiral configuration upon loading, utilizing a combination of annular elements and offset connecting elements to maximize fracture resistance and induce swirling blood flow, reducing stress concentrations and vascular disease development.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the device is configured in a straight, cylindrical shape in the unloaded state, then ease of delivery and insertion is improved, but fracture resistance under compressive loading deteriorates
Solution Approach 1:
The device transitions from a straight cylindrical configuration in the unloaded state to a three-dimensional curved configuration in the loaded state. This dynamic shape change allows the device to be easily delivered in a straight form while automatically assuming a fracture-resistant curved shape when subjected to compressive loading in the body lumen.
Solution Approach 2:
The device utilizes changes in geometric parameters (from straight to curved configuration) in response to loading conditions. The transition between unloaded and loaded configurations alters the spatial arrangement of the device structure, maximizing fracture resistance when needed while maintaining ease of delivery when not loaded.
2Strength
If the device adopts a three-dimensional curved shape in the loaded configuration, then fracture resistance is maximized, but device complexity increases
Solution Approach 1:
The device comprises a plurality of annular elements connected by connecting elements, forming a segmented structure. This segmentation allows the device to achieve a complex three-dimensional curved configuration through the arrangement and connection of simpler modular components, reducing overall manufacturing complexity while maintaining structural integrity.
Solution Approach 2:
The device is designed to naturally form a three-dimensional curved shape (such as helical or spiral configurations) when loaded, rather than requiring complex active control mechanisms. This passive curvature approach maximizes fracture resistance through geometric optimization while minimizing the complexity of control systems.
3Manufacturing precision
If the device remains in a straight configuration, then manufacturing precision is easier to achieve, but stress concentration under compressive loading increases
Solution Approach 1:
The device transitions from a straight configuration during manufacturing and delivery to a three-dimensional curved configuration during operation. This dynamic transformation allows the device to be manufactured with simple straight geometry (easy manufacturing precision) while automatically assuming a stress-distributing curved shape when deployed and loaded in the body lumen.
4Shape
If the device uses multiple annular elements with offset connecting elements, then the three-dimensional curved shape is facilitated, but device complexity increases
Solution Approach 1:
The device is divided into multiple annular elements connected by connecting elements, with the connecting elements offset circumferentially between adjacent annular elements. This segmentation strategy enables the formation of three-dimensional curved shapes through the cumulative effect of offset connections, achieving complex geometry through simple modular repetition rather than requiring a single complex structure.
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 device enhances fracture resistance and minimizes thrombosis and intimal hyperplasia by accommodating blood vessel deformations and promoting swirling blood flow, thereby inhibiting vascular diseases like thrombosis and atherosclerosis.
Implementation Method 1
the device being movable from an unloaded configuration to a loaded configuration upon application of a load to the device
Implementation Method 2
the three-dimensional curved shape of the device maximises the fracture resistance of the device. In the case of certain types of loading, for example compressive loading, the three-dimensional curved shape of the device may minimise points of stress concentration
Implementation Method 3
induce swirling blood flow, reducing stress concentrations and vascular disease development
Data Source
AI summary
A stent suitable for deployment in a blood vessel to support at least part of an internal wall of the blood vessel comprises a plurality of longitudinally spaced-apart annular elements, and a plurality of connecting elements to connect adjacent annular elements. Each connecting element is circumferentially offset from the previous connecting element. Upon application of a load to the stent, the stent moves from an unloaded configuration to a loaded configuration. In the unloaded configuration the longitudinal axis of the stent is straight, and the stent is cylindrically shaped. In the loaded configuration the longitudinal axis of the stent is curved in three-dimensional space, and the stent is helically shaped.