Guidewire Thermal Segmentation for Hook Shaping and Durability
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Solution Overview
Problem
Existing guidewires made of superelastic alloys face challenges in shaping performance, particularly in forming a hook shape at the distal end, and durability issues such as folding during use.
Innovation Solution
A guidewire design featuring a core shaft with a thermally-transformed portion and a sparsely-wound coil on the distal end, where the coil has gaps between adjacent wire portions, enhancing shaping performance and durability by maintaining superelasticity and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the core shaft is made of superelastic material throughout, then durability is improved, but shaping performance deteriorates
Solution Approach 1:
The core shaft is divided into multiple segments with different thermal transformation states. The distal end portion includes a first segment that is thermally transformed to suppress superelastic characteristics for easy shaping, while a second segment maintains superelasticity for durability. This segmentation allows each portion to fulfill its specific function without compromising the other.
Solution Approach 2:
Different portions of the core shaft are given different properties through selective thermal transformation. The distal end portion is thermally transformed to reduce superelasticity and improve shaping performance, while the proximal portion retains full superelasticity for durability. This local differentiation of material properties resolves the contradiction between shaping ease and durability.
2Strength
If the coil is densely wound, then structural integrity is improved, but shaping performance deteriorates
Solution Approach 1:
The coil structure is differentiated into densely wound portions for structural integrity and sparsely wound portions for shaping flexibility. The sparsely wound portion at the distal end allows easy shaping into hook shapes, while the densely wound portions maintain overall structural integrity.
3Ease of manufacture
If the entire core shaft is thermally transformed, then shaping performance is improved, but durability deteriorates
Solution Approach 1:
The core shaft is segmented into a first segment that is thermally transformed for shaping performance and a second segment that retains superelasticity for durability. This selective thermal transformation approach allows the guidewire to be easily shaped while maintaining resistance to folding and damage during use.
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 allows for easy shaping into hook and body shapes, improves flexibility, and enhances durability by reducing thermal conductivity and flexural rigidity changes, facilitating navigation through various blood vessel diameters.
Implementation Method 1
a first segment consisting of a thermally-transformed portion in which the superelastic material has been thermally transformed
Implementation Method 2
the coil has a sparsely-wound portion on a distal end portion in which a gap is formed between portions of the wire that are adjacent to each other
Implementation Method 3
the second segment is formed having a thermally-transformed portion having a shorter length than the first segment, or is formed not having a thermally-transformed portion, and the superelasticity of the core shaft is maintained
Data Source
AI summary
A guidewire is provided with a core shaft made of a superelastic material, and a coil formed of a wire that has been spirally wound around the outer periphery of the distal end portion of the core shaft. A section of the core shaft positioned on an inner side of the coil has a first segment consisting of a thermally-transformed portion in which the superelastic material has been thermally transformed, and a second segment that is positioned on a rear end side of the first segment. In the second segment, a thermally-transformed portion having a shorter length than the first segment is formed, or no thermally-transformed portion is formed. The distal end portion of the coil has a sparsely-wound portion in which gaps are formed between portions of the wire that are adjacent to each other.