Catheter Braid Asymmetry for Bifurcation Navigation
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Solution Overview
Problem
Catheters with isotropic rotational force at bifurcations struggle to change direction from a major canal to a minor canal, leading to difficulties in inserting the distal end into a side branch due to the inability to deform the bend, resulting in increased time for reaching stenosis or occlusion sites.
Innovation Solution
A catheter with a braid comprising a high-tensile strength first wire and a low-tensile strength second wire, woven helically, allows the bend to form an arc in the winding direction of the first wire, enabling deformation into a thin state when rotated in the same direction, facilitating direction change from a major canal to a minor canal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a catheter is provided with a bend at the distal end oriented towards a predetermined direction, then the distal end can be oriented towards an offset direction, but the rotational force transmitted to the distal end is isotropic, preventing the bend from deforming when the distal end is caught at a bifurcation
Solution Approach 1:
The braid is constructed with first wires having higher tensile strength and second wires having lower tensile strength, creating an asymmetric structure. When the catheter is rotated in a specific direction, the high-tensile first wires resist deformation while the low-tensile second wires allow controlled deformation of the bend, enabling directional control and bend deformation when the distal end is caught at a bifurcation.
Solution Approach 2:
Different regions of the braid have different wire properties - the first wires provide high tensile strength for maintaining catheter shape and transmitting torque, while the second wires provide low tensile strength to allow bend deformation. This local differentiation of material properties enables the catheter to simultaneously maintain structural integrity and allow controlled deformation.
2Productivity
If the distal end of the catheter is caught by a portion around the entrance of the minor canal at a bifurcation, then the catheter cannot proceed further, but with isotropic rotational force the bend cannot be deformed to free the distal end
Solution Approach 1:
The asymmetric braid structure with high-tensile first wires and low-tensile second wires enables anisotropic rotational force transmission. When the catheter is rotated in the direction where the low-tensile second wires are engaged, the bend can be deformed to free the distal end from being caught at the bifurcation entrance, reducing the time required to reach the target site.
3Stability of the object's composition
If wires of the same diameter are woven as a braid, then the tensile strength is uniform, but this creates isotropic rotational force that prevents selective bend deformation
Solution Approach 1:
The braid incorporates wires with different tensile strengths at different positions, creating local quality variations. The high-tensile first wires provide structural stability and uniform torque transmission, while the low-tensile second wires are strategically positioned to allow controlled deformation in specific directions, enabling the catheter to adapt its shape as needed.
Solution Approach 2:
The braid is constructed as a composite structure combining materials or wire configurations with different tensile strengths. This composite approach allows the catheter to exhibit both uniform overall strength for stable navigation and localized deformability for adapting to bifurcations and freeing caught distal ends.
Data Source
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AI summary
A catheter (1,1a,1b) including a catheter shaft (10a,10b,10c) including a body portion (12,12a,12b), and a bend (14,14a,14b,14c) that extends from the body portion towards the distal end (11b, 11d, 11g). In the catheter, a braid (30) in which a first wire (30a,30c,30e) that has a high tensile strength and a second wire (30b,30d,30f) that has a low tensile strength are helically woven together is installed inside the catheter shaft. When viewed from a proximal end (11a,11c,11f) of the catheter shaft, the bend forms an arc that extends in a winding direction (X) of the first wire.