Variable Pitch Catheter Coil for Flexibility and Torque
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Solution Overview
Problem
Conventional catheters with a coil body face challenges in increasing the outer diameter to facilitate larger balloon catheter insertion without compromising flexibility and torque transmissibility, leading to difficulties in navigating meandering blood vessels and maintaining occluded area dilation efficiency.
Innovation Solution
A catheter design with a distal portion having a larger pitch between coils than the proximal portion, achieved through electro-polishing and heat-treating, ensures higher flexibility at the distal end while maintaining rigidity at the proximal end, allowing for stable guide wire operation and efficient occluded area dilation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the outer diameter of the coil body is increased to facilitate larger balloon catheter insertion, then the ability to accommodate large balloon catheters is improved, but the flexibility of the coil body deteriorates
Solution Approach 1:
The patent applies local quality by creating a distal portion with a larger pitch between coils than the proximal portion. This means the coil structure has different characteristics at different locations: the distal end has wider spacing between coils to increase flexibility for navigation, while the proximal end maintains tighter coil spacing to preserve rigidity for torque transmission. This local differentiation resolves the contradiction by allowing each region to optimize for its specific functional requirement.
2Volume of moving object
If the outer diameter of the coil body is increased to facilitate larger balloon catheter insertion, then the ability to accommodate large balloon catheters is improved, but the torque transmissibility deteriorates
Solution Approach 1:
The patent resolves the torque transmissibility contradiction through local quality by maintaining a smaller pitch between coils in the proximal portion. This tighter coil spacing in the proximal region ensures that torque applied at the proximal end is effectively transmitted to the distal end, while the distal portion uses a larger pitch to provide flexibility. This spatial differentiation allows the coil body to simultaneously achieve large outer diameter for balloon catheter insertion and maintain reliable torque transmissibility.
3Ease of operation
If the pitch between coils is increased at the distal portion to enhance flexibility, then the flexibility at the distal end is improved, but the rigidity at the proximal end deteriorates
Solution Approach 1:
The patent directly applies local quality to resolve this contradiction by implementing different pitch values at different locations along the coil body. The distal portion uses a larger pitch to maximize flexibility for navigating meandering blood vessels, while the proximal portion uses a smaller pitch to maintain rigidity for effective torque transmission. This localized structural differentiation allows each region to be optimized independently for its specific mechanical requirements.
4Volume of moving object
If the outer diameter of the coil body is increased without changing wire thickness, then the outer diameter is improved, but the guiding stability deteriorates
Solution Approach 1:
The patent resolves the guiding stability contradiction through local quality by maintaining a consistent, small pitch between coils throughout the coil body structure. This uniform, tight coil spacing ensures that the guide wire can be stably guided through the coil body regardless of the outer diameter size. The distal portion's larger pitch provides flexibility without compromising the overall guiding stability, as the proximal portion's consistent pitch maintains proper guide wire engagement and control.
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 catheter enables simple, quick, and safe dilation of occluded areas to accommodate large balloon catheters without reducing operation performance, reducing operator and patient burden by ensuring sufficient flexibility and torque transmissibility.
Implementation Method 1
a distal portion 16 having a pitch P in a coil body 10 formed by winding or stranding at least one wire 12, wherein a distance Wd between coils adjacent to each other in the distal portion 16 is greater than a distance Wp between coils adjacent to each other in a portion adjacent to the distal portion 16 toward a proximal end 14 of the coil body 10
Implementation Method 2
heat-treating, ensures higher flexibility at the distal end while maintaining rigidity at the proximal end
Data Source
AI summary
A catheter body includes a coil body (10) which is formed by winding or stranding metal wires (12) and having a distal portion (16) and a proximal portion. The distance between coils (12) adjacent to each other in the distal portion (16) is greater than the distance between coils (12) adjacent to each other in the proximal portion (18 or 14). The pitch in the distal portion (16) of the coil body (10) is substantially or nearly the same as the pitch in the proximal portion (18 or 14).