Direct Pullwire Anchoring in Catheters for Stable Articulation
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Solution Overview
Problem
Existing steerable catheters face challenges with mechanical instability, inconsistent articulation, and increased tracking forces due to compressive forces on flexible catheter shafts, leading to undesired deflection and rotation, especially when navigating tortuous anatomies, and require multiple catheters for varying anatomical access, increasing cost and time.
Innovation Solution
A catheter design with a flexible polymer body incorporating a wire support structure, such as a braided tubular structure, where pullwires are anchored between tubular layers, and a proximal adapter for steerable control, allowing for consistent articulation and reduced shaft deflection, with optional rapid exchange architecture for improved navigation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a flexible catheter shaft is used to navigate tortuous anatomies, then the catheter can access diverse anatomical targets, but mechanical instability and undesired deflection occur due to compressive forces
Solution Approach 1:
The catheter shaft is divided into multiple articulated segments that can bend and flex independently. Each segment contains pullwires that when tensioned, articulate the distal section in controlled directions. This segmentation allows the catheter to navigate tortuous anatomies while maintaining overall structural stability through controlled articulation rather than uncontrolled deflection.
Solution Approach 2:
The catheter incorporates a control ring at the distal end with pullwires positioned at specific locations (e.g., 12, 3, 6, and 9 o'clock positions). By selectively tensioning individual pullwires, the operator can articulate the distal section in precise directions. This local control mechanism provides stability in articulation while maintaining the flexibility needed for anatomical navigation.
2Ease of operation
If pullwires are positioned offset from the neutral axis to enable articulation, then steering control is achieved, but compressive forces cause curve alignment and rotation
Solution Approach 1:
The pullwires are intentionally positioned asymmetrically relative to the neutral axis of the catheter shaft, at specific circumferential positions (12, 3, 6, and 9 o'clock). This asymmetric positioning enables effective steering control by creating differential tension when pullwires are tensioned. The control ring with offset pullwire anchorages allows the distal section to articulate in controlled directions while the asymmetric configuration inherently manages the curve alignment phenomenon through geometric design.
3Adaptability or versatility
If multiple catheters are used to access varying anatomical targets, then comprehensive coverage is achieved, but cost and procedure time increase
Solution Approach 1:
The catheter is designed with a control ring and multiple pullwires that can articulate the distal section in multiple directions (at least four distinct directions). This multi-functional articulation capability allows a single catheter to access diverse anatomical targets that would traditionally require multiple specialized catheters. The universal design with selectively tensionable pullwires provides comprehensive anatomical coverage while reducing procedure time and cost by eliminating the need to exchange catheters.
Data Source
AI summary
A catheter comprises a flexible polymer catheter body including a proximal shaft section and a distal working section, a wire support structure embedded within the distal working section of the catheter body, a proximal adapter mounted to the proximal shaft section of the catheter body, and a wire disposed within the catheter body. The wire has a proximal end and a distal end. The proximal end of the wire being operably connected to the proximal adapter, and the distal end of the wire is anchored to the wire support structure.