String-Equipped Stent Knot Layout for Accurate Deployment
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Solution Overview
Problem
Existing stent deployment methods are prone to positional deviations due to uneven reaction forces from narrowing portions, as the string intersections expand in a single direction, failing to existing technologies, making precise placement challenging.
Innovation Solution
A manufacturing method involving alternating first and second knots on the stent string, where each knot is formed in opposite circumferential directions, ensuring balanced reaction force distribution and accurate placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If multiple intersection portions are linearly arranged in the axial direction at a single place in the circumferential direction, then the stent can be easily expanded by pulling the wire, but a single place in the circumferential direction expands first causing reaction force concentration and positional deviation
Solution Approach 1:
The string is divided into multiple segments with intersection portions distributed at different circumferential positions rather than concentrated at a single location. This segmentation of the tying points along the axial direction ensures that expansion forces are distributed evenly around the stent circumference, preventing concentrated reaction forces that would cause positional deviation during deployment
Solution Approach 2:
The intersection portions are positioned asymmetrically at different circumferential locations around the stent rather than symmetrically at the same location. This asymmetric distribution of tying points ensures balanced expansion forces in all circumferential directions, eliminating the concentration of reaction forces at a single point that would otherwise cause the stent to deviate from the target position
2Device complexity
If the stent is tied with a string having intersection portions concentrated at one circumferential location, then the structure is simple, but reaction forces cause the stent to expand unevenly and deviate from target position
Solution Approach 1:
The string structure is segmented into multiple tying sections with intersection portions located at different circumferential positions. This segmentation distributes the mechanical constraints around the stent, ensuring uniform expansion behavior and accurate deployment to the target position while maintaining reasonable structural simplicity
Solution Approach 2:
The intersection portions are distributed along the axial dimension of the stent rather than being concentrated in a single circumferential plane. This dimensional redistribution of the string constraints transforms the expansion mechanism from concentrated circumferential force to distributed three-dimensional constraints, improving deployment accuracy
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 method allows for precise and accurate deployment of the stent at the target position by alternately expanding and contracting the stent, minimizing positional deviations caused by reaction forces.
Implementation Method 1
a stent (5) that is passed in a tubular portion in a body of a subject and that is expanded by elasticity of the stent to be able to indwell within the tubular portion
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A manufacturing method of a stent with a string 4 includes a first knot forming step of forming a first bent portion 12a at a string 6 and forming a first knot 11a by passing a part on the other end side 6h of the string 6 with respect to the first bent portion 12a between the first bent portion 12a and a stent 5 in one circumferential direction around the stent 5 and a second knot forming step of forming a second bent portion 12b at the part passed between the first bent portion 12a and the stent 5 and forming a second knot 11b by passing a part on the other end side 6h of the string 6 with respect to the second bent portion 12b between the second bent portion 12b and the stent 5 in the other circumferential direction around the stent 5, which is an opposite direction to a direction of passing the first bent portion 12a. The first knot 11a is formed on a first side 5x when viewed in an axial direction AX of the stent 5, and the second knot 11b is formed on a second side 5y, which is an opposite side to the first side 5x.