Bi-directional Catheter Steering Handle Mechanism
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Solution Overview
Problem
Current deflectable catheters can only deflect in one direction due to the limitations of pull wires, which restrict active deflection control and often result in passive straightening without the ability to deflect in opposing directions.
Innovation Solution
A bi-directional deflectable catheter design featuring first and second pull wires anchored at the distal end, with a threaded member and slider block mechanism in the handle that allows for rotation-induced translation, enabling deflection in two opposing orientations by altering the direction and point of force application through a U-shaped tube.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single pull wire is used for deflection control, then the catheter can be deflected in one direction, but the catheter cannot be actively deflected in more than one direction
Solution Approach 1:
The deflection control system is segmented into multiple independent pull wires (first pull wire and second pull wire), each responsible for deflection in a specific direction. This segmentation allows the catheter to be deflected in multiple directions by independently controlling each pull wire, resolving the limitation of single-direction deflection while maintaining manageable system complexity through modular wire control.
Solution Approach 2:
The handle assembly serves multiple functions: it houses the threaded member for bidirectional translation, contains both first and second pull wires for multi-directional deflection, and provides a unified control interface. This multi-functionality allows a single handle structure to control deflection in multiple directions without proportionally increasing overall device complexity.
2Ease of operation
If a pull wire is compressed in one direction, then the wire buckles, but active deflection control in the opposite direction is prevented
Solution Approach 1:
Instead of attempting to compress the pull wire to achieve deflection in the opposite direction (which causes buckling), the system inverts the approach by using tension on the pull wire in the opposite direction. The threaded member translates in reverse, applying tension to the pull wire to pull the catheter tip in the opposite direction, thereby maintaining wire structural integrity while achieving bidirectional deflection control.
Solution Approach 2:
The threaded member acts as an intermediary between the rotational input and the pull wire tension. It converts rotational motion into bidirectional translational motion, which then applies controlled tension to the pull wire in either direction. This intermediary mechanism eliminates direct compression of the pull wire while enabling reliable bidirectional deflection control.
3Adaptability or versatility
If the sheath relies on natural elasticity for straightening, then the distal end can straighten in one direction, but active deflection in the opposed direction is not provided
Solution Approach 1:
The pull wire is pre-configured and anchored at both the handle and the catheter tip, with the threaded member positioned to apply tension in either direction before deflection is needed. This preliminary setup allows the operator to actively engage the pull wire in either direction through simple rotation of the threaded member, eliminating the need to rely on passive elastic straightening and providing active control capability in both directions without significantly increasing device complexity.
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
Enables active deflection of the catheter's distal end in multiple directions, providing greater maneuverability and flexibility during medical procedures, particularly in accessing the vasculature, with a compact handle design for precise control.
Implementation Method 1
A threaded member is housed in the handle and threadingly mates to a slider block. That way, when a rotatable member of the handle is rotated, it causes the threaded member to rotate and translate the slider block in either a forwardly or backwardly direction along the handle.
Implementation Method 2
The pull wire may only be tensioned in one direction thereby providing for deflection in a single direction.
Implementation Method 3
The U-shaped tube changes the direction and point of application of a pulling force applied to the second pull wire.
Implementation Method 4
the threaded member translates the slider block in a rearwardly direction against the first stop member to apply a first pulling force on the first pull wire. This force causes the distal sheath end to deflect into a first orientation out of alignment with respect to a longitudinal axis of the sheath.
Data Source
AI summary
A deflectable sheath for use in medical procedures in the vasculature is described. The sheath includes a handle supporting the sheath. Two pull wires run along opposite sides of the sheath to anchors at the deflectable distal end. The handle includes a rotatable member that moves a threaded slider block in a back and forth translational manner. As that translational movement occurs, force is applied to either one or the other of the pull wires to cause deflection of distal end of the sheath in either and upwardly or a downwardly direction with respect to the longitudinal axis of the sheath.