Non-Overlapping Wire Stent Minimizes Foreshortening
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Solution Overview
Problem
Existing stents, particularly those with braided, knitted, or overlapping structures, tend to migrate from their deployed position due to foreshortening during deployment, making precise positioning challenging and complicating the treatment of biliary duct blockages, while laser-cut stents are prone to tissue ingrowth and cannot be re-constrained after partial deployment.
Innovation Solution
A stent configuration featuring a tubular member formed by non-overlapping wire segments with a specific pattern of turns and connecting segments that span gaps between rows, allowing for minimal foreshortening and ease of re-constraint, and optionally coated to prevent tissue ingrowth, facilitating precise placement and long-term stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a braided, knitted, or overlapping wire structure is used to provide flexibility and compressibility for stent delivery, then the stent can be delivered through catheters, but the stent tends to migrate from its deployed position due to foreshortening during deployment
Solution Approach 1:
The stent wire is divided into multiple discrete segments arranged in rows, with gaps between consecutive rows. Each segment can be independently positioned and constrained, preventing the foreshortening migration that occurs in continuous braided or knitted structures. The segmentation allows the stent to maintain its deployed position while still providing necessary flexibility.
Solution Approach 2:
The wire configuration transitions from traditional planar braided/knitted patterns to a three-dimensional arrangement with multiple rows stacked axially. The connecting segments bridge gaps between rows in the axial dimension, creating a spatial framework that prevents foreshortening while maintaining compressibility for delivery.
2Device complexity
If laser-cut stents are used to avoid tissue ingrowth, then the stent structure is simplified, but the stent cannot be re-constrained after partial deployment
Solution Approach 1:
The stent employs a dynamic wire configuration where segments can be independently constrained or released. The connecting segments between rows can be selectively constrained to lock the stent in place or released to allow re-constraint, providing adaptability that static laser-cut structures cannot achieve.
Solution Approach 2:
The stent design allows partial deployment followed by re-constraint by selectively constraining connecting segments. This enables the stent to be adjusted after initial placement, a capability that can be recovered or modified during the procedure, unlike permanent laser-cut structures.
3Manufacturing precision
If wire segments are arranged in multiple rows with gaps between them, then foreshortening is minimized and positioning precision is improved, but the manufacturing complexity increases
Solution Approach 1:
The connecting segments serve multiple functions: they bridge gaps between rows, provide structural continuity, enable foreshortening resistance, and allow for re-constraint. This multi-functionality reduces the need for additional complex structural elements while maintaining positioning precision.
Solution Approach 2:
The wire configuration uses specific geometric parameters (gap sizes, connecting segment lengths, angles) that can be optimized during manufacturing. By controlling these parameters, the stent achieves minimal foreshortening and precise positioning while maintaining manufacturability through standardized wire forming processes.
Data Source
AI summary
Devices, systems, and methods for treating defects in anatomical structures are disclosed. A device may include a stent having a tubular member with a first end, a second end, and a lumen between the first end and the second end. A wire having a first end and a second end may form a plurality of annular rows between the first end and the second end, where the rows may define the lumen. The wire of the stent may define a plurality of turns in each row of the plurality of annular rows and may have no overlapping portions along the rows. A gap may extend between consecutive rows of the plurality of rows and a connecting segment may span across the gap to interconnect two rows of the plurality of rows. The connecting segment may be the only portion of the wire that spans across the gap.