Medical Guidewire Nested Tube Joints Resilience
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Solution Overview
Problem
Medical guidewires face issues with residual angles and reduced operability due to plastic deformation when bent into a U-shape, especially in small-diameter blood vessels, leading to misinsertion and reduced flexibility.
Innovation Solution
A guidewire design featuring a core shaft with a small-diameter distal end, surrounded by an outer flexible tube and an inner flexible tube, with strategically positioned joints to differentiate rigidity along the guidewire, preventing excessive bending and allowing selective operation based on target vessel size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the diameter of the distal end portion of the core shaft is made small to improve flexibility, then the guidewire becomes more flexible and can be inserted into small-diameter blood vessels, but the guidewire is easily bent due to stress concentration and undergoes plastic deformation when bent into a U-shape
Solution Approach 1:
The patent employs a nested structure where an inner flexible tube is disposed inside the outer flexible tube, both surrounding the core shaft. This nested configuration allows the guidewire to maintain flexibility while the inner tube provides resilience by surrounding and supporting the core shaft during bending operations.
Solution Approach 2:
The guidewire uses a composite structure combining a core shaft with flexible tubes made of different materials or configurations. The outer flexible tube and inner flexible tube create a composite system that provides both flexibility for insertion and resilience for maintaining shape after bending.
2Reliability
If the guidewire is bent into a U-shape to prevent misinsertion or secure holding, then the guidewire can be properly positioned in the target blood vessel, but plastic deformation occurs and a residual angle remains even after the U-shaped bending is released
Solution Approach 1:
The guidewire is segmented into distinct functional portions: a core shaft and flexible tubes with joints at specific locations. This segmentation allows the distal end portion to be bent into a U-shape for positioning while the proximal portion maintains its shape, preventing excessive bending from propagating through the entire guidewire.
Solution Approach 2:
The patent applies different mechanical properties to different portions of the guidewire. The distal end portion is designed with higher flexibility to allow U-shaped bending for positioning, while the proximal portion maintains higher rigidity to prevent deformation, creating local quality differences that satisfy both positioning accuracy and operability requirements.
3Reliability
If joints are added to differentiate rigidity along the guidewire to prevent excessive bending, then the guidewire can maintain functionality and prevent plastic deformation, but the device complexity increases
Solution Approach 1:
The nested structure of the inner and outer flexible tubes within the core shaft provides structural complexity that is functionally integrated. The joints are positioned at specific locations where the nested tubes are disposed, allowing the complexity to be organized in a way that prevents excessive bending while maintaining functional integrity.
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 enhances resilience and flexibility, preventing plastic deformation and allowing controlled U-shape bending, ensuring accurate insertion and easy operation by limiting U-shaped bends to high-resilience portions, thus maintaining guidewire functionality.
Implementation Method 1
the inner flexible tube is disposed in the outer flexible tube, the inner flexible tube surrounding the distal end portion of the core shaft... the resilience of the guidewire is improved because the inner flexible tube surrounds the outer surface of the core shaft
Implementation Method 2
A first joint is formed so as to join the distal end of the inner flexible tube to the core shaft, and at least one second joint is formed so as to join the outer flexible tube to the inner flexible tube
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
Provided is a guidewire (1) including a core shaft (2), an outer flexible tube (4), and an inner flexible tube (5) that surrounds a distal end portion of the core shaft. The inner flexible tube is disposed in the outer flexible tube so that a distal end thereof is positioned between the distal end of the core shaft and a proximal end of the core shaft so as to be separated from the core shaft. A first joint (6) is formed so as to join the distal end of the inner flexible tube to the core shaft. At least one second joint (7a,7b) is formed so as to join the outer flexible tube to the inner flexible tube. The at least one second joint is positioned between the first joint and the proximal end of the core shaft.