Rectangular Guidewire Shaft with Arcuate Projections
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Solution Overview
Problem
Conventional guidewires experience increased operation resistance and reduced torque transmission characteristics when inserted into extremely winding blood vessels, leading to decreased operability and potential vessel damage.
Innovation Solution
A shaft with an approximately rectangular cross-section featuring arcuate projections and recesses on its sides, and a guidewire with a coiled body composed of helically wound strands, which reduces contact areas with the blood vessel wall, enhancing torque transmission and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional guidewire shaft is used, then the structure is simple, but operation resistance increases and torque transmission characteristics deteriorate when passing through winding blood vessels
Solution Approach 1:
The shaft cross-section incorporates arcuate projections with specific radius of curvature (smaller than the virtual circle diameter), creating a curved geometry that reduces contact area with the blood vessel wall. This curvature design allows the shaft to navigate winding pathways more effectively while maintaining torque transmission capability.
Solution Approach 2:
The shaft features an asymmetric cross-sectional shape with projections on only two opposite sides rather than a complete circular or uniformly symmetric shape. This asymmetric design with recesses on the other two sides creates selective contact points that reduce friction and improve ease of operation in tortuous vessels.
2Ease of operation
If the shaft cross section is circular, then the shape is simple and symmetric, but contact area with blood vessel wall increases causing higher operation resistance
Solution Approach 1:
Instead of a simple circular cross-section, the invention employs a rectangular cross-section with arcuate projections that create a more complex curved geometry. This shape reduces the contact area with the blood vessel wall by concentrating contact at specific projected points rather than along the entire circumference.
Solution Approach 2:
The circular cross-section is segmented into a rectangular shape with distinct projections and recesses. This segmentation creates discrete contact zones (the projections) separated by non-contact zones (the recesses), thereby reducing overall contact area and operation resistance.
3Ease of manufacture
If the shaft has a rectangular cross-section without projections, then manufacturing is simple, but contact area with blood vessel wall is excessive causing sliding resistance
Solution Approach 1:
The rectangular cross-section is modified by adding arcuate projections with specific curvature radii. These curved projections reduce sliding resistance by creating point contacts rather than line contacts with the blood vessel wall, while still maintaining relative manufacturing simplicity through standard forming processes.
Solution Approach 2:
The rectangular cross-section is enhanced by adding projections only at specific locations (two opposite sides) rather than uniformly around the entire perimeter. This local modification optimizes the balance between manufacturing complexity and operational performance by concentrating the functional benefit where most needed.
Data Source
AI summary
Provided is a shaft capable of suppressing the rise in operation resistance when pushed and pulled even inside an extremely winding blood vessel to secure sufficient torque transmission characteristics so that operability is improved, and a guidewire employing the shaft. A shaft 10 is twisted along a longitudinal direction, having a cross section taking the form of an approximately rectangular shape in a direction vertical to the longitudinal direction. Moreover, the cross section of the shaft 10 has a projection 14 projected arcuately.