Biodegradable Stent with Elastic Threads for Reliable Expansion
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Solution Overview
Problem
Conventional self-expanding biodegradable stents face challenges in loading into delivery systems due to high resistance and inadequate end-portion expansion, leading to difficulties in deployment and potential deformation over time.
Innovation Solution
A stent design featuring connecting points at end portions offset in two or more rows, incorporating elastic threads as warp threads to enhance expanding force and facilitate loading and deployment, with elastic threads fixed to the braid to ensure reliable expansion without additional members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the diameter of threads is increased to increase the expanding force, then the expanding force increases, but the stent becomes difficult to load into the delivery system
Solution Approach 1:
The connecting points are segmented into two separate rows instead of being concentrated in one location. This segmentation distributes the structural reinforcement across different positions, allowing the stent to have both sufficient expanding force and reduced loading resistance.
Solution Approach 2:
The thread diameter is optimized locally - thicker threads are used where expanding force is needed, while the connecting points are strategically positioned in two rows to minimize interference with delivery system loading. This local optimization allows different parts of the stent to have different functional characteristics.
2Strength
If the threads are connected at the stent end portions, then the stent structure is strengthened, but the connecting portions become larger and interfere with loading into the delivery system
Solution Approach 1:
The connecting points are arranged in two rows along the length direction of the braid, transitioning from a single-point connection to a distributed linear arrangement. This dimensional change allows the connections to be spread out, reducing the concentration of bulk at any single location and facilitating easier loading into the delivery system.
3Adaptability or versatility
If the stent is stored in a collapsed state for a long period, then the stent is ready to use whenever necessary, but the stent may deform and the expanding force decreases
Solution Approach 1:
The stent is pre-formed with a specific three-dimensional shape and connecting points arranged in two rows before sterilization and storage. This preliminary structuring ensures that the stent maintains its geometric integrity and expanding force characteristics during long-term storage in the collapsed state, preventing deformation.
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 design allows for easier loading into delivery systems, reduces the force required for deployment, and ensures reliable and uniform expansion of the stent, maintaining performance over time.
Implementation Method 1
a plurality of elastic threads are further incorporated in the braid as warp threads and extend in the length direction
Implementation Method 2
a stent formed by braiding a plurality of filament threads containing a biodegradable polymer into a cylindrical braid
Data Source
Figure 1A
Figure 1B~1D
Figure 2A
AI summary
A stent 51c is formed by braiding a plurality of filament threads containing a biodegradable polymer into a cylindrical braid, and connecting points 53a-53d at end portions of the filament threads constituting the braid are arranged in two or more rows in a length direction of the braid. Elastic threads 54a-54d are each disposed outside at least a part of the stent 51c and along at least a part of the stent in the length direction including the vicinity of either one of end portions of the stent. One end of each elastic thread is fixed to the vicinity of the end portion of the stent, and the other end is fixed to any portion of the stent. In a state in which the stent is radially contracted, tension may be applied to the elastic threads. Thus, provided are a stent that is easy to load into a delivery system and also facilitates the expanding operation, as well as a medical device including the stent.