Helically Braided Endoprosthesis for Strength-Flexibility Balance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing endoprostheses often compromise on mechanical and functional characteristics such as axial foreshortening, radial expansion, flexibility, and resistance to migration due to uniform filament orientations, necessitating the need for alternative configurations that balance these properties.
Innovation Solution
The endoprosthesis is designed with a helical braid pattern where filaments intersect at varying angles relative to the central longitudinal axis, forming closed cells with offset corners and incorporating longitudinal reinforcing elements, allowing for improved torqueability, hoop strength, and resistance to axial elongation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a typical braid is optimized to prevent axial foreshortening and/or prevent radial expansion under pressure, then axial stability and radial strength are improved, but flexibility and deliverability are compromised
Solution Approach 1:
The patent applies local quality by varying the braid angle along the length of the endoprosthesis. Different sections have different braid angles, allowing the proximal end to have higher radial strength while the distal end maintains flexibility for navigation. This gradient approach resolves the contradiction by optimizing each location for its specific functional requirements rather than using a uniform structure throughout.
Solution Approach 2:
The patent implements dynamics by making the braid angle variable rather than fixed. The braid angle changes continuously or in steps along the length of the device, enabling dynamic adaptation of mechanical properties. This allows the endoprosthesis to transition from a rigid support structure at the proximal end to a more flexible configuration at the distal end, resolving the contradiction between strength and flexibility.
2Ease of manufacture
If filaments are oriented at the same angle relative to the central longitudinal axis, then manufacturing simplicity is maintained, but mechanical performance is compromised
Solution Approach 1:
The patent applies parameter changes by varying the braid angle parameter along the length of the endoprosthesis. Instead of maintaining a constant braid angle, the angle is changed as a function of position, allowing optimization of mechanical performance while using standard braiding techniques. This resolves the contradiction by showing that parameter variation can be achieved with conventional manufacturing methods.
3Length of moving object
If the endoprosthesis wall thickness is reduced to improve deliverability, then flexibility and ease of insertion are improved, but radial strength and structural integrity are compromised
Solution Approach 1:
The patent applies local quality by concentrating higher braid angles (and thus higher radial strength) at the proximal end where structural support is most needed, while using lower braid angles at the distal end to maintain flexibility and reduce profile for delivery. This spatial variation in braid angle allows the device to have sufficient radial strength without requiring uniformly thick walls throughout, resolving the contradiction between strength and deliverability.
Data Source
AI summary
An endoprosthesis extending along a central longitudinal axis includes a plurality of filaments interwoven to form a plurality of closed cells having corners defined by cross-over points formed by the filaments. Each filament is oriented at a different angle relative to the central longitudinal axis. The cross-over points of each closed cell may include proximal and distal cross-over points, and first and second lateral cross-over points, wherein the distal cross-over point is circumferentially offset from the proximal cross-over point of its respective closed cell. A method of manufacturing includes securing a plurality of filaments extending from a braiding machine to a mandrel such that the filaments form a braid tent oriented at an intersecting angle with the mandrel; and interweaving the filaments around the mandrel to form a plurality of closed cells having corners defined by cross-over points formed by the filaments while rotating the mandrel.