Double-Walled Flange Stent for Migration Resistance
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Solution Overview
Problem
Existing stents are prone to dislodgment or migration due to patient motion and may not provide adequate retentive force, failing to maintain effective fluid communication between body lumens.
Innovation Solution
A self-expanding stent design featuring double-walled flanges with non-parallel surfaces, including curved and straight edges, which provide increased pull-out resistance and reduce migration by engaging tissue layers with less trauma, thereby maintaining apposition of body lumen layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional stent design is used, then the stent can be easily manufactured and installed, but the stent is prone to dislodgment or migration due to patient motion
Solution Approach 1:
The stent is divided into multiple retention members (first retention member and second retention member) positioned at different locations along the stent body. Each retention member acts as an independent segment that engages with tissue layers, distributing the retentive force throughout the stent structure rather than relying on a single complex anchoring mechanism.
Solution Approach 2:
The retention members feature non-parallel walls with asymmetric geometries. The first wall and second wall of each retention member are positioned at different angles relative to the stent longitudinal axis, creating asymmetric engagement patterns that prevent migration in multiple directions while maintaining manufacturability through standardized expansion processes.
2Reliability
If the stent provides sufficient retentive force to prevent migration, then the stent remains stable in position, but the stent may cause increased tissue trauma
Solution Approach 1:
The retention members are designed with differentiated wall configurations tailored to specific local requirements. The first wall engages with a first body lumen wall while the second wall engages with a second body lumen wall, with each wall's geometry optimized for its specific engagement location. This localized optimization provides sufficient retentive force while minimizing tissue damage at each interface.
Solution Approach 2:
The retention members incorporate curved surfaces and rounded transitions rather than sharp edges. The walls are formed with smooth curvature that allows gradual engagement with tissue layers, reducing stress concentration and tissue trauma while maintaining effective retentive force through the curved geometry's mechanical advantage.
3Strength
If the stent uses a simple flange structure, then the manufacturing is easier, but the pull-out resistance is insufficient
Solution Approach 1:
The retention members are designed to dynamically adapt to tissue forces during deployment and operation. The non-parallel walls are configured to engage progressively as the stent expands, with the geometry allowing the retention members to flex and conform to tissue contours while maintaining retentive force. This dynamic engagement provides high pull-out resistance without requiring overly complex manufactured structures.
Data Source
AI summary
The present disclosure relates generally to the field of medical devices. In particular, the present disclosure relates to medical devices for facilitating the flow of fluids and materials in and/or between adjacent body lumens, for example, a stent which maintains an open flow passage between body lumens. In one example, a stent may comprise an elongate body configured to be expandable between a first constrained configuration and a second unconstrained configuration. In the unconstrained configuration, the body may have a first retention member, a second retention member, and a cylindrical saddle region defining a lumen extending along a longitudinal axis therebetween. The first retention member or the second retention member, or both, may comprise a double-walled flange with an axially inward wall and axially outward wall, a portion of the inward wall bending towards a vertical center plane of the saddle region along the longitudinal axis.