Steerable Catheter Pullwire Divergence for Articulation Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Steerable catheters face challenges such as inconsistent articulation performance, curve alignment, and mechanical instability due to the interaction of pullwires with the catheter shaft, leading to unintended rotation and lateral deflection.
Innovation Solution
The design employs multiple pullwires to steer the distal tip in a single direction, with these pullwires diverging into a more spaced distribution in the proximal shaft section, creating a bending moment in the distal articulating section without bending the shaft. This configuration allows for independent control of the articulating section while minimizing shaft bending and rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the catheter shaft is made laterally flexible to follow anatomy curvature, then tracking performance improves, but articulation performance becomes inconsistent and unstable
Solution Approach 1:
The catheter shaft is divided into multiple discrete segments or struts that can independently articulate. This segmentation allows the shaft to maintain flexibility for tracking while providing controlled articulation points that prevent unwanted lateral deflection and improve articulation consistency.
Solution Approach 2:
The catheter employs dynamic articulation mechanisms where the angle between shaft segments can be actively adjusted and controlled. This dynamic capability allows the system to maintain stable articulation performance while adapting to anatomical curvatures, resolving the contradiction between flexibility and control consistency.
2Ease of operation
If pullwires are positioned offset from the neutral axis to enable steering, then articulation capability improves, but shaft compression and unwanted bending increase
Solution Approach 1:
The invention transitions from a traditional pullwire system operating in one dimension to a multi-strut system that operates in multiple dimensions. By using struts positioned at various angles and lengths, the system achieves articulation capability while distributing forces to minimize shaft compression and unwanted bending through geometric configuration rather than offset positioning.
Solution Approach 2:
The invention changes the fundamental parameters of the steering mechanism by varying strut lengths, angles, and positions to optimize the balance between articulation capability and shaft stability. By adjusting these geometric parameters, the system achieves effective steering while minimizing harmful compressive forces and unwanted bending moments.
3Ease of operation
If multiple pullwires are used to steer the distal tip, then articulation control improves, but shaft muscling and lateral deflection increase
Solution Approach 1:
The system segments the articulation function into multiple independent strut elements rather than using multiple pullwires. Each strut can be independently controlled to articulate the distal tip, providing precise articulation control while distributing the mechanical loads to prevent shaft muscling and lateral deflection that would result from multiple pullwires acting on a flexible shaft.
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
This design achieves predictable and controlled articulation of the catheter tip, reduces shaft muscling and unwanted bending, and allows for the manufacture of thinner-walled catheters with improved maneuverability and tracking performance.
Implementation Method 1
creating a bending moment in the distal articulating section without bending the shaft
Data Source
AI summary
A steerable catheter system may include a flexible elongate catheter body, a drive mechanism at the proximal end of the catheter body, and at least one group of pullwires extending along a length of the catheter body. The catheter body may include a distal articulating section and a proximal non-articulating section. Each group of pullwires includes at least two pullwires, and each of the pullwires is anchored at a first end to the distal end of the catheter body and at a second end to the drive mechanism. The pullwires of each group are positioned close to one another in the catheter wall to concentrate the forces and cause deflection along the articulating section of the catheter body and diverge away from one another to reach a more separated distribution around a circumference of the catheter body to distribute the forces and prevent deflection along the non-articulating section.