Curved Electrode Catheter Structure to Prevent Twisting and Kinking
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Solution Overview
Problem
Conventional catheters experience issues with twisting of the curving axis, kinking, and decreased pushability due to the deformation of the coil connected to the leaf spring, which affects the ability to achieve a desired curved shape and deliver the distal end to the desired location without damaging the lumen wall.
Innovation Solution
A catheter design featuring a shaft, wire, leaf spring, and cover tube configuration where the cover tube is fixed to the shaft outside the coil, preventing the coil from deforming and twisting, thereby maintaining stiffness and allowing controlled bending without kinking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the coil is compressed by pulling of the wire to ensure stiffness of the base end, then the coil is deformed to spread in the radial direction, but this causes the connection between the coil and the leaf spring to rotate, resulting in twisting of the curving axis
Solution Approach 1:
A fixation member is introduced as an intermediary component between the coil and the catheter tube. This fixation member has a first fixation portion that engages with the coil and a second fixation portion that is fixed to the catheter tube, thereby preventing the coil from rotating or deforming radially while maintaining the curving axis alignment. The intermediary structure transmits the stiffness requirement without causing twisting.
2Stability of the object's composition
If the connection part is fixed to the catheter tube to prevent twisting, then the fixed part becomes hard, but this creates a stiffness step with sudden change in hardness, causing kinking or decreased pushability
Solution Approach 1:
The fixation member is designed with localized fixation portions rather than continuous fixation along the catheter tube. The first fixation portion engages with the coil at specific locations, and the second fixation portion is fixed to the catheter tube at discrete positions. This localized approach provides stability where needed while maintaining flexibility and gradual stiffness transition in other regions, preventing sudden hardness changes that cause kinking.
3Stability of the object's composition
If a conductive wire is placed in the fixed part, then the conductive wire is also fixed, but this hinders the catheter from bending, adversely affecting the shape of the bend
Solution Approach 1:
The fixation structure is segmented into distinct regions: the fixation member provides stable anchoring at the proximal end where the coil connects to the catheter tube, while the distal end and intermediate sections remain flexible. This segmentation allows the proximal portion to maintain curving axis alignment through fixation while the distal portions can bend freely to achieve desired curved shapes without hindrance from continuous fixation.
Data Source
AI summary
The objective is to provide a catheter that can realize a desired curved shape by preventing the curving axis of the catheter distal part from twisting, and preventing the catheter from kinking and decreased pushability. Disclosed is a catheter (1) having a shaft (2); at least one wire (30); a coil (60); a leaf spring (40) extending in the longitudinal direction and having a first connection part where its proximal part is fixed to a distal end part of the coil (60); and a cover tube (50) that is disposed outside the coil (60) and has a first fixed part (51) where it is fixed to the shaft (2) at a position proximal to the distal end of the coil (60) in the longitudinal direction.