Electrode Catheter Torque Transmission via Segmented Braid Design
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Solution Overview
Problem
The existing electrode catheters with braided tube shafts suffer from insufficient torque transmission, particularly when a guide-wire lumen is present, and face challenges in machining side holes for leads due to the complex resin-metal combination, which can damage insulation coatings.
Innovation Solution
An electrode catheter design featuring a catheter shaft with a guide-wire lumen and a braided tube structure reinforced by a resin braid throughout, where side holes are easily formed without exposing metal wires, allowing leads coated with a resin to pass through without damaging the insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the distal end part of the catheter shaft is constituted by a braided tube reinforced by a metal braid, then torque transmission is improved, but machining to form side holes becomes extremely difficult and metal wire materials are exposed on the inner circumferential surface
Solution Approach 1:
The catheter shaft is divided into two segments with different reinforcement characteristics: the proximal end part is reinforced by a metal braid for high torque transmission, while the distal end part is reinforced by a resin braid for ease of machining. This segmentation allows each part to be optimized for its specific function without compromising the other.
Solution Approach 2:
Different parts of the catheter shaft are given different local qualities in terms of reinforcement material. The proximal end uses metal braid reinforcement for strength, while the distal end uses resin braid reinforcement for machinability. This local differentiation resolves the contradiction between strength and ease of manufacture.
2Strength
If the distal end part of the catheter shaft is constituted by a braided tube reinforced by a metal braid, then torque transmission is improved, but resin covering layer of the lead may be damaged by exposed metal wire materials
Solution Approach 1:
The catheter shaft is segmented into proximal and distal parts with different braid materials. The distal end part uses resin braid reinforcement that does not expose sharp edges, thereby protecting the lead insulation from damage while maintaining sufficient torque transmission for the distal portion.
Solution Approach 2:
The resin braid in the distal end part acts as a protective layer that prevents damage to the lead insulation, similar to how a sacrificial protective layer works. It may wear or deform but protects the critical lead insulation from damage.
3Ease of operation
If a large-diameter central lumen is formed for guide-wire insertion, then guide-wire insertion is enabled, but the ratio of space to shaft increases and torque transmission is reduced
Solution Approach 1:
The catheter shaft has non-uniform reinforcement distribution: the proximal end has strong metal braid reinforcement for torque transmission, while the distal end has lighter resin braid reinforcement that allows for a larger guide-wire lumen diameter. This local quality differentiation enables both adequate torque transmission and guide-wire insertion capability.
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
An object is to provide an electrode catheter excellent in terms of torque transmission compared with a hitherto publicly known electrode catheter. An electrode catheter of the present invention comprises a catheter shaft 10; ring-shaped electrodes 201 to 210; and leads 301 to 310 of the ring-shaped electrodes 201 to 210, in which the catheter shaft 10 is constituted by an inside tube 11 that has a guide-wire lumen 11L and an outside tube 13 that forms a lumen 12L into which the leads 301 to 310 are inserted, the outside tube 13 being configured by a braided tube reinforced by a braid 135 made of a resin throughout the entire length thereof; in which side holes 15 are formed in the tube wall of the outside tube 13 at the distal end part 101 of the catheter shaft 10 in correspondence to the attachment positions of the ring-shaped electrodes 201 to 210; and in which the leads 301 to 310 enter the lumen 12L through the side holes 15 and extend in said lumen 12L.