Bi-directional Sheath Deflection via Dual Pull Wire Mechanism
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Solution Overview
Problem
Current deflectable sheaths can only deflect in one direction due to the limitations of pull wires, which restrict active deflection control and rely on the natural elasticity for opposing movements, lacking the ability to actively change orientation in multiple directions.
Innovation Solution
A bi-directional deflectable sheath design featuring two pull wires anchored at the distal end and a threaded member in the handle, allowing for independent control of deflection in multiple orientations through a rotatable mechanism that translates along the sheath, enabling deflection in both upward and downward directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single pull wire is used for deflection control, then the structure is simple, but the sheath can only deflect in one direction
Solution Approach 1:
The single pull wire system is segmented into two separate pull wires (first pull wire and second pull wire), each responsible for controlling deflection in opposite directions. This segmentation allows independent control of deflection in both directions while maintaining structural simplicity
Solution Approach 2:
The threaded member and carriage mechanism serve multiple functions: they can tension either the first pull wire or the second pull wire depending on the direction of rotation, enabling bidirectional deflection control through a single actuator system
2Adaptability or versatility
If pull wire compression is prevented by buckling, then the wire structure is simple, but active deflection control in multiple directions is lost
Solution Approach 1:
The system dynamically switches between tensioning the first pull wire and tensioning the second pull wire based on the desired deflection direction. The threaded member can move in either forward or rearward direction, dynamically engaging the appropriate wire for active control in the desired direction
3Ease of operation
If natural elasticity is used for sheath straightening, then no additional control mechanism is needed, but active deflection control is lost
Solution Approach 1:
The sheath utilizes its natural elasticity to automatically return to a straight configuration when pull wire tension is released, eliminating the need for separate active straightening mechanisms while maintaining full bidirectional deflection control capability
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 and controlled deflection of the sheath's distal end in multiple orientations, providing greater maneuverability and flexibility during medical procedures, particularly in accessing the vasculature, while maintaining a compact and ergonomic handle design.
Implementation Method 1
A threaded member is housed in the handle and comprises a cylindrical bore that receives the proximal sheath portion in a longitudinally slidable relationship. The threaded member includes a carriage carrying a wire guide retainer. That way, when a rotatable member of the handle is rotated, it causes the threaded member to translate in either a forwardly or backwardly direction along the proximal portion of the sheath.
Implementation Method 2
when a rotatable member of the handle is rotated, it causes the threaded member to translate in either a forwardly or backwardly direction along the proximal portion of the sheath. A first pull wire extends from a first distal end anchored to the deflectable distal sheath end, past the wire guide retainer to a proximal pulley and then back through a first bore in the wire guide retainer to a proximal first pull wire end provided with a first stop member located distally of the wire guide retainer.
Implementation Method 3
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. On the other hand, when the rotatable member is manipulated in a second direction, opposite the first direction, the threaded member carrying the wire guide retainer translates along the proximal sheath portion in a rearwardly direction against the second stop member to apply a second pulling force on the second pull wire. This force causes the distal sheath end to deflect into a second orientation out of alignment with respect to the 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 member including wire guide in a back and forth translation. As the 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.