Micro-fabricated Medical Device Non-helical Cut Pattern
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Solution Overview
Problem
Interventional devices such as guidewires and catheters face challenges in navigating tortuous vasculature due to preferred bending directions caused by traditional cut patterns, which hinder flexibility and torquability.
Innovation Solution
The implementation of a non-helical and non-linear cut pattern with distributed fenestrations and rotational offsets minimizes preferred bending directions, enhancing the device's flexibility and torquability while maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional helical or linear cut patterns are used to increase flexibility, then the device can bend more easily, but preferred bending directions are created that hinder navigation control
Solution Approach 1:
The patent applies asymmetry by using non-uniform spacing between fenestrations and non-helical angular offsets around the longitudinal axis. This asymmetric arrangement eliminates the periodic preferred bending directions that occur with uniform helical or linear patterns, allowing the device to bend flexibly in any direction without snapping to a preferred orientation.
Solution Approach 2:
The patent segments the wall structure by creating multiple fenestrations that divide the continuous wall into discrete segments. This segmentation increases flexibility by allowing individual segments to move relative to each other, while the distributed non-helical arrangement ensures that bending can occur uniformly in all directions rather than being constrained to specific orientations.
2Object-affected harmful factors
If fenestrations are added to improve flexibility, then the device can navigate tortuous pathways better, but torquability and pushability are reduced
Solution Approach 1:
The patent applies local quality by strategically positioning fenestrations with non-uniform spacing and angular offsets. This creates localized flexibility at specific segments while maintaining overall structural integrity. The non-helical distribution ensures that flexibility is provided where needed without compromising the torque transmission capability of the entire device.
Solution Approach 2:
The patent creates a composite structure by combining solid wall material with fenestrated regions. This composite arrangement provides a balance between flexibility (from the fenestrated segments) and strength (from the solid material), allowing the device to navigate tortuous pathways while maintaining sufficient torquability and pushability.
3Object-affected harmful factors
If helical cut patterns are used to reduce preferred bending bias, then bending flexibility is improved, but the device tends to coil or twist in the direction of helical rotation
Solution Approach 1:
The patent inverts the conventional helical approach by using non-helical angular offsets. Instead of maintaining a consistent rotational direction around the longitudinal axis, the fenestrations are positioned with varying angular offsets that do not follow a helical pattern. This inversion eliminates the coiling tendency while preserving bending flexibility in all directions.
Solution Approach 2:
The patent uses asymmetry in the angular positioning of fenestrations to prevent the symmetric coiling behavior associated with helical patterns. By distributing fenestrations with non-uniform angular offsets, the device achieves flexible bending without the tendency to twist or coil in a preferred rotational direction.
Data Source
AI summary
The present disclosure relates to interventional devices such as catheters and guidewire devices having micro-fabricated features for providing flexibility while maintaining good torquability. An interventional device includes an elongated member having an arrangement of fenestrations which define a plurality of axially extending beams coupling a plurality of circumferentially extending rings. The fenestrations are arranged so that the resulting beams form a distributed, non-helical and non-linear pattern along the length of the elongated member. The pattern of fenestrations thereby minimizes or eliminates preferred bending axes.