Steerable Catheter Handle with Cam and Follower Mechanism
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Solution Overview
Problem
Conventional catheter control systems offer limited flexibility, requiring complex combinations of actuation to control the magnitude and direction of catheter flex, making it difficult to intuitively steer a catheter in transvascular procedures.
Innovation Solution
The use of cam and follower mechanisms with adjustable cam shapes and multiple followers allows for independent control of catheter flex magnitude and direction, enabling precise steering without rotating the entire catheter, utilizing a handle with knobs for axial and rotational adjustments of the cam to manage pull wire tension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional catheter control systems use multiple levers or dials coupled to pull wires for each direction, then the catheter can be steered in multiple directions, but the control system becomes complex and difficult to operate intuitively
Solution Approach 1:
The control system is segmented into independent magnitude control and direction control functions. The magnitude control adjusts the degree of flexion uniformly, while the direction control rotates the cam to select the steering direction, separating these two control aspects that were previously integrated in conventional multi-lever systems.
Solution Approach 2:
A single cam structure serves multiple functions: it controls both the magnitude of catheter flexion through axial movement and the direction of flexion through rotational movement. This multi-functional cam replaces the need for multiple separate levers or dials, simplifying the control interface while maintaining full steering capability.
2Device complexity
If conventional catheter control systems integrate magnitude and direction control in a single mechanism, then the system structure is simplified, but the control precision and independence of each parameter are reduced
Solution Approach 1:
The cam mechanism is designed with separable control inputs: axial movement of the cam controls flexion magnitude independently, while rotational movement of the cam controls flexion direction independently. This segmentation within the unified cam structure allows precise independent control of both parameters without requiring multiple separate mechanisms.
Solution Approach 2:
The cam mechanism dynamically transitions between controlling magnitude (through axial displacement) and controlling direction (through rotation). The follower rides along the cam surface, and the operator can independently adjust the cam's axial position and rotational angle, providing dynamic and independent control of both parameters through a single integrated structure.
3Ease of operation
If cam and follower mechanisms are used to control pull wire tension, then independent control of flex magnitude and direction is achieved, but the device complexity increases
Solution Approach 1:
Multiple control functions (magnitude control and direction control) are merged into a single cam structure. The cam combines the functions of multiple levers or dials that would otherwise be needed, reducing the number of separate components while maintaining independent control capability through its dual degrees of freedom (axial and rotational movement).
Solution Approach 2:
The cam acts as a universal control element that performs multiple functions: it controls pull wire tension magnitude through axial movement and controls the distribution of tension among different pull wires through rotation. This multi-functionality reduces the need for separate specialized components for each control function.
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 solution provides intuitive, fine control over catheter steering, allowing for precise radial and circumferential adjustments, reducing the complexity of steering and enhancing the ability to maneuver catheters in transvascular procedures.
Implementation Method 1
steerable catheter assemblies that utilize cam and follower mechanisms to accomplish independent control of catheter flex magnitude and catheter flex direction
Implementation Method 2
Rack and pinion assemblies as well as pulley assemblies can be included to magnify motion that is applied to pull wires
Data Source
AI summary
Steerable catheters include cam and follower mechanisms that provide independent control of catheter flex magnitude and catheter flex direction to provide improved steerability of an attached catheter. In certain embodiments, the steerable catheter assemblies include two or more pull wires that flex the catheter, and a control handle coupled to the catheter having a direction control and a magnitude control, both of which are operably coupled to the two or more pull wires by the cam and follower mechanism. In embodiments disclosed herein, the cam and follower system can be modified to achieve particular catheter control.