Dual Braid Catheter Shaft Steering Wire Delamination
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Solution Overview
Problem
Existing catheter shaft constructions face issues with steering wires delaminating from the internal lumen and occupying space, which reduces the availability for other components like irrigation and additional wiring, and can lead to mechanical instability during medical procedures.
Innovation Solution
The solution involves encapsulating steering wires between the inner and outer braids of a dual braided catheter shaft, providing a robust attachment and increasing space within the lumen for other uses, while maintaining mechanical properties for stability and torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If steering wires are threaded through the central lumen and held by a thin liner, then the catheter can be steered to the desired location, but the pull wires can delaminate from the inside surface of the lumen and occupy space that reduces availability for other components
Solution Approach 1:
The patent moves the steering wires from the central lumen (one-dimensional space) to the radial dimension by positioning them between the inner and outer braids. This dimensional transition eliminates the delamination problem while preserving steering functionality, as the wires remain securely anchored in the braid structure rather than relying on adhesion to the lumen surface.
Solution Approach 2:
The steering wires are nested within the dual braid structure, specifically positioned between the inner braid and outer braid layers. This nesting approach provides robust mechanical support and secure attachment for the steering wires, eliminating the need for separate adhesive liners and preventing delamination while maintaining the catheter's steerable characteristic.
2Strength
If the shaft is constructed with extruded polymer layers and metal braid, then the shaft provides mechanical strength and incompressibility, but the internal lumen space is reduced and the structure becomes more complex
Solution Approach 1:
The dual braid structure serves multiple functions simultaneously: the inner braid provides compression resistance, the outer braid provides torsional rigidity, and together they create a stable framework that accommodates steering wires without requiring additional support structures. This multi-functionality eliminates the need for separate reinforcement elements that would further reduce lumen space.
Solution Approach 2:
The patent employs a composite structure combining polymer extruded layers with metal braid elements. The inner polymer layer provides a smooth, biocompatible surface and flexibility, while the inner and outer metal braids provide structural strength and rigidity. This composite approach optimizes the balance between mechanical strength and internal lumen space by efficiently distributing structural functions across different materials.
3Adaptability or versatility
If multiple wires are threaded through the central lumen, then the catheter can perform multiple functions, but the wires may short circuit and the structure becomes more complex
Solution Approach 1:
The patent transitions from a one-dimensional wire arrangement (all wires in the central lumen) to a multi-dimensional configuration where steering wires are positioned radially between the braids and electrode wires can be positioned in the central lumen. This spatial separation in different dimensions eliminates the risk of short circuits while maintaining multi-functionality, as each wire type occupies a distinct spatial zone.
Solution Approach 2:
The catheter shaft is segmented into functionally distinct zones: the central lumen accommodates electrode wires, while the radial space between the inner and outer braids accommodates steering wires. This segmentation isolates different wire types, preventing electrical interference and simplifying the overall structure by assigning specific spatial responsibilities to different wire functions.
Data Source
AI summary
A dual braided catheter shaft includes an inner helical braid and outer helical braid than encapsulate an axially extending steering wire there between. In one embodiment, the shaft includes an inner polymer jacket, an inner braid formed on the inner jacket, a steering wire disposed along an outside surface of the inner braid, an outer braid formed over the inner braid and steering wire assembly and an outer jacket formed on the outer braid. The braiding parameters of the inner and outer braids can be varied along the length of the catheter to provide varying mechanical properties.