Segmented Wire Guide Stiffness Flexibility Trade-off
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Solution Overview
Problem
Wire guides face a design challenge in balancing stiffness and flexibility, as increased stiffness often leads to decreased flexibility and vice versa, making it difficult to navigate body lumens without damaging tissues.
Innovation Solution
A wire guide design featuring a proximal core wire with high modulus of elasticity and a distal core wire with low modulus of elasticity, combined with a sleeve, where the distal core wire is secured within a recess or covered by a sleeve, allowing for enhanced pushability and flexibility while minimizing tissue damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the wire guide is made with high stiffness material, then the wire guide can be pushed through body lumens with sufficient force, but the wire guide becomes too rigid and may damage the body lumen or plastically deform
Solution Approach 1:
The wire guide is divided into multiple segments with different material properties: a proximal segment with high stiffness material for pushability and a distal segment with low stiffness material for flexibility. This segmentation allows each segment to perform its specific function without compromising the other, resolving the contradiction between needing stiffness for propulsion and flexibility for tissue safety.
Solution Approach 2:
Different portions of the wire guide are assigned different local qualities (stiffness characteristics). The proximal portion uses high stiffness material to provide adequate pushability, while the distal portion uses low stiffness material to provide flexibility and prevent tissue damage. This local differentiation of properties directly addresses the contradiction by optimizing each region for its specific functional requirement.
2Object-affected harmful factors
If the wire guide is made with high flexibility material, then the wire guide can navigate body lumens without damage, but the wire guide lacks sufficient stiffness for the surgeon to push through
Solution Approach 1:
The wire guide is segmented into a proximal high-stiffness section for force transmission and a distal low-stiffness section for safe navigation. This segmentation ensures that the pushability function is isolated to the proximal segment while the distal segment provides the necessary flexibility, eliminating the need to compromise between these opposing requirements in a uniform structure.
Solution Approach 2:
The wire guide exhibits local quality variations along its length, with the proximal region having high stiffness for adequate pushability and the distal region having low stiffness for flexibility. This spatial variation in material properties allows the wire guide to simultaneously achieve both pushability and tissue safety without requiring a uniform compromise in either direction.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design provides improved strength and flexibility, enabling wire guides to be pushed through body channels without kinking or causing damage, while maintaining sufficient stiffness for navigation.
Implementation Method 1
a proximal core wire comprised of a first material having a high modulus of elasticity
Implementation Method 2
a distal core wire comprised of a second material having a low modulus of elasticity
Implementation Method 3
the sleeve material being weldable to the first material
Data Source
AI summary
A wire guide and methods for making the same is provided. The method includes joining a proximal core wire comprised of a stiff material to a distal core wire comprised of a highly elastic wire material. The proximal core wire may have a recess at a distal face and the distal core wire is secured within the recess. The recess may be machined into the distal face of the proximal core wire. The distal core wire may be a coaxial wire having a sleeve of material that is easily weldable to the proximal core wire. The sleeve is welded to the proximal core wire and a distal portion of the sleeve is then removed to expose the distal core wire.