Corrugated Catheter Structure for Flexible, Kink-Resistant Navigation
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Solution Overview
Problem
Endovascular procedures face a trade-off between catheter diameter, trackability, flexibility, and kink resistance, with increased diameter leading to stiffness and decreased flexibility, and increased flexibility causing kinking, limiting access to tortuous vessels.
Innovation Solution
A catheter design featuring a jacket with a helical support and a corrugated outer surface, including a transition portion with varying flexural stiffness, and a distal portion with a soft tip extension, optimized for flexibility and kink resistance, combined with a flow restrictor for aspiration systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If catheter diameter is increased, then catheter stiffness increases, but trackability and flexibility decrease
Solution Approach 1:
The catheter incorporates different structural characteristics in different sections: the distal portion has a corrugated outer surface with deeper corrugations for flexibility, while the proximal portion has a smooth outer surface for stiffness. This local differentiation allows each section to perform its specific function optimally without compromising the other.
Solution Approach 2:
The catheter wall is constructed as a composite structure with multiple layers including an inner liner, a jacket with helical support, and corrugated outer surface. This composite construction provides both the necessary flexibility and structural integrity, combining materials and structures that offer different mechanical properties.
2Ease of operation
If catheter flexibility is increased, then access to tortuous vessels improves, but kink resistance decreases
Solution Approach 1:
The catheter incorporates a helical support structure within the wall, which provides a curved, spring-like geometry that naturally resists kinking while maintaining flexibility. The helical configuration allows the catheter to bend and conform to vessel curves without collapsing or forming sharp kinks.
Solution Approach 2:
The corrugated outer surface acts as a flexible shell structure that can bend and deform elastically to navigate tortuous vessels while the helical support embedded within provides structural reinforcement to prevent kinking. The corrugations themselves provide flexibility while the overall structure maintains kink resistance.
3Ease of operation
If wall thickness is decreased, then flexibility increases, but kink resistance and structural integrity worsen
Solution Approach 1:
The catheter wall uses a composite construction with an inner liner layer, a jacket layer with helical support, and an outer corrugated layer. This multi-layer composite structure achieves high flexibility with thin walls while the helical support provides the necessary kink resistance and structural integrity that would otherwise require much thicker walls.
Solution Approach 2:
The helical support is strategically positioned within the wall structure at locations where kink resistance is most needed, providing localized reinforcement without increasing overall wall thickness. The corrugated outer surface provides flexibility where needed while the helical support prevents kinking.
Data Source
AI summary
A catheter has a jacket (10, 11, 5) defining a lumen and a helical support (6). The catheter has a proximal portion (4) and a distal portion (3), the distal portion having for at least some of its length a corrugated outer surface. A transition portion has a flexural stiffness which is less than that of the distal portion and more than that of the proximal portion. The transition portion provides an optimum transition in flexural stiffness by way of features of the jacket including geometry of jacket corrugations (15), or overlapping tubular layers (1073, 1074). The distal end of the distal portion may have an extension of liner material folded over (1072, 1082) to provide a particularly soft tip. In other examples the liner is terminated (763) before the distal tip. The catheter is particularly suited to an aspiration device (1350) with a flow restrictor (1353) and the distal portion distal of the flow restrictor. An aspiration system (3500) may employ the catheter with a pump which dynamically applies negative or positive pressure to optimally aspirate a clot.