Stent Retrieval via Radial Collapse to Prevent Vascular Wall Tearing
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Solution Overview
Problem
Existing stent retrieval systems are complex and prone to causing damage to the vascular wall during stent removal, as they often require substantial axial pulling and radial contraction, which can lead to tearing and complications, especially in weak vascular areas.
Innovation Solution
A stent and retrieval system design featuring a tubular member with a lumen and a retrieval member that engages with a stent's annular rows of cells, where the engagement member has three tie members connected at a junction and extends to attachment points circumferentially offset from cell connections, allowing for radial collapse and gentle release from the vascular wall without substantial axial pull.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional retrieval systems use substantial axial pulling and radial contraction to remove the stent, then the stent can be retrieved from the vascular site, but the vascular wall is damaged through tearing and complications
Solution Approach 1:
The stent structure is segmented into multiple annular rows of cells with interconnection areas, allowing differential movement of each row during retrieval. The engagement member selectively engages with specific cells in the end row, enabling localized radial collapse without requiring substantial axial pulling force that would damage the vascular wall.
Solution Approach 2:
The engagement member is designed with tie members that extend to specific attachment points on the end row of cells, creating localized engagement zones. This allows radial forces to be applied selectively to the end row cells, causing them to collapse locally while the rest of the stent remains stable, thereby minimizing vascular wall damage during retrieval.
2Object-affected harmful factors
If the engagement member uses tie members extending to attachment points circumferentially offset from cell connections, then radial collapse occurs without substantial axial pull, but the device structure becomes more complex
Solution Approach 1:
The engagement member combines multiple functions into a single structure: the tie members simultaneously provide engagement with the cells, transmit radial forces, and maintain structural integrity. The junction where tie members connect serves as both a structural node and a force distribution point, reducing the need for separate components and simplifying the overall device despite the complex engagement geometry.
3Reliability
If the end row of cells is engaged at circumferentially offset attachment points, then secure engagement is achieved, but the stent requires specialized retrieval mechanisms
Solution Approach 1:
The engagement member design with tie members extending to circumferentially offset attachment points provides reliable engagement with the stent's end row cells. This same engagement mechanism also enables controlled radial collapse and maintains stent stability during retrieval, making the retrieval system versatile for different stent configurations without requiring specialized components for each function.
Data Source
AI summary
A stent has an engagement member (9). A stent retrieval system has a tubular member (13) and a retrieval member (14) with an engagement means (15). The engagement member is attached to an end row of cells of the tubular stent body (1). The cells in one annular row of cells are interconnected with the subsequent row of similarly oriented cells (2a) at areas of interconnection (7) which in the subsequent annular row of cells are circumferentially offset with respect to the connections (8) between the cells in said subsequent annular row of cells.