Medical Device Mesh Wire Fixation Stress Reduction
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Solution Overview
Problem
Conventional medical devices with mesh members used for dilating calcified stenosis or stricture in blood vessels or digestive organs face issues due to stress concentration and wire breakage, as the lining and wrapping portions interfere with wire movement during radial expansion and contraction, preventing proper contour following and effective dilation.
Innovation Solution
A medical device with a mesh member woven from first and second wires, where the cylindrical member's wrapping and lining portions are fixed within spaces defined by the wires, allowing free movement and reducing stress concentration, and featuring a projected-and-depressed outer surface to minimize friction and improve delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the lining portion and wrapping portion are firmly fixed to the end of the mesh member, then the structural stability is improved, but the wires are likely to break due to stress concentration
Solution Approach 1:
The fixation portions are segmented into discrete locations within the spaces between wires, rather than continuous fixation along the wire length. This segmentation allows the wires to move independently at non-fixation points, reducing stress concentration while maintaining structural stability at fixation points.
Solution Approach 2:
The fixation is applied locally at specific portions of the lining and wrapping portions, not uniformly across the entire structure. The fixation portions are strategically positioned within spaces between wires, creating local stability zones while preserving wire mobility in other areas.
2Stability of the object's composition
If the lining portion and wrapping portion are firmly fixed to the mesh member, then the structural support is improved, but the device cannot follow curved contours
Solution Approach 1:
The fixation structure is segmented into discrete portions located within wire spaces, allowing different regions of the mesh member to have different degrees of freedom. This enables the distal end to conform to curved contours while maintaining structural support through the fixation portions.
Solution Approach 2:
The structure transitions from a static, uniformly fixed design to a dynamic configuration where fixation portions allow controlled movement. The wires can adjust their angles and positions in response to curved anatomical contours while the fixation portions provide necessary structural support.
3Strength
If the wrapping portion and lining portion are fixed to the wires, then the fixation strength is improved, but stress concentrates at the wire ends
Solution Approach 1:
The fixation portions are extracted from direct contact with the wires and repositioned within the spaces between adjacent wires. This extraction eliminates the stress concentration that would occur at wire ends if fixation were applied directly to the wires, while maintaining adequate fixation strength through the space-based anchoring.
Solution Approach 2:
The spaces between wires serve as intermediary zones for fixation, rather than fixing directly to the wires themselves. This intermediary positioning distributes stress more evenly and prevents stress concentration at wire ends while maintaining fixation strength through the space-based anchoring mechanism.
Data Source
AI summary
A medical device includes a mesh member capable of radially expanding and contracting, and a cylindrical member located at one end of the mesh member. The mesh member is woven from a first wire and a second wire. The cylindrical member includes a wrapping portion and a lining portion that are fixed to each other at fixation portions positioned within spaces defined by the first wire and the second wire. Neither the wrapping portion nor the lining portion is fixed to either of the first wire or the second wire. Upon expansion or radial contraction of the mesh member, movement of the first wire or the second wire is not interfered with by the cylindrical member. This reduces the concentration of stress at the end of the mesh member and thus the likelihood that either the first wire or the second wire will break.