Catheter Pull Wire Anchoring for Stress Fracture Prevention
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Solution Overview
Problem
Current methods for anchoring catheter pull wires to pull rings are susceptible to stress fractures and detachment due to high pull forces required for precise catheter navigation, especially in thicker or longer catheters, leading to mechanical integrity issues.
Innovation Solution
A system and method involving an annular band with multiple apertures and receiving slots for securing a round pull wire, combined with a fusible thermoplastic band to enhance the strength of the connection, allowing for increased pull force without compromising design integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If welding is used to attach the pull wire to the pull ring, then the connection strength is improved, but the susceptibility to stress fractures and peeling increases under repeated destructive pull force
Solution Approach 1:
The pull ring is divided into multiple segments or zones with different material properties or structural characteristics. This segmentation allows different regions to handle different types of stresses - some regions resist pull force while others accommodate deformation, preventing stress concentration at any single weld point and reducing fracture susceptibility.
Solution Approach 2:
The pull ring is constructed from composite materials combining different metal alloys or material layers. This composite structure provides both high strength to withstand pull forces and enhanced toughness to resist stress fractures under repeated loading, resolving the contradiction between connection strength and fracture resistance.
2Area of stationary object
If a flat distal end is used on the pull wire for attachment, then the attachment area is improved, but the stress concentration at the transition point increases leading to wire breakage
Solution Approach 1:
The distal end of the pull wire is designed with a curved or rounded geometry rather than a flat termination. This curvature eliminates sharp corners and abrupt transitions that concentrate stress, allowing the wire to withstand higher pull forces without breaking at the attachment point while still providing adequate attachment area through the curved surface.
3Area of stationary object
If the pull ring is made larger to increase attachment area, then the connection strength is improved, but the pull ring becomes more susceptible to detachment from the catheter shaft
Solution Approach 1:
Different regions of the pull ring have different material properties or structural characteristics. The portions interacting with the catheter shaft have enhanced retention features such as increased friction coefficients, mechanical interlocking elements, or chemical bonding capabilities, while other portions provide the necessary attachment area for the pull wire without compromising shaft retention.
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 enhanced anchoring system significantly increases the connection strength between the pull wire and pull ring, enabling higher pull forces while maintaining mechanical integrity, reducing the risk of detachment and breakage.
Implementation Method 1
a fusible thermoplastic band to enhance the strength of the connection
Implementation Method 2
fusible thermoplastic band to enhance the strength of the connection
Implementation Method 3
the wire may be welded to the band in four locations
Data Source
AI summary
A system and method for anchoring a round catheter pull wire within the distal end of a catheter. A steering deflection mechanism includes a pull ring having a plurality of apertures and one or more receiving slots. The method includes affixing one or more round pull wires to the one or more receiving slots of the pull ring. The shape of the round wire and manner of affixing the wire to the pull ring provide a steering assembly that can withstand greater pull forces while maintaining design integrity.