Catheter Multi-Layer Outer Jacket Staggered Durometer Transitions
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Solution Overview
Problem
Medical catheters with single-layer outer jackets are prone to buckling and kinking when navigating through tortuous blood vessels due to abrupt changes in durometer, which can hinder their navigation and effectiveness in medical procedures.
Innovation Solution
A multi-layer outer jacket design with staggered transition portions between layers, where each layer includes segments with varying durometers, is used to create a smooth durometer gradient, reducing the likelihood of buckling and kinking by evenly distributing stiffness changes along the catheter length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-layer outer jacket is used with abrupt durometer changes, then the catheter can be manufactured with simpler structure, but the catheter is prone to buckling and kinking
Solution Approach 1:
The outer jacket is divided into multiple layers, each containing multiple segments with different durometers. This segmentation allows the catheter to have a complex durometer gradient profile while maintaining manufacturing feasibility through modular construction. Each segment can be independently formed and then assembled into the final multi-layer structure.
Solution Approach 2:
The outer jacket uses composite construction with multiple layers of different materials or configurations, where each layer has segments with varying durometers. This composite approach enables the catheter to achieve a smooth durometer gradient that prevents buckling and kinking while providing the necessary structural integrity and flexibility for navigation.
2Ease of operation
If multiple outer jacket segments with different durometers are used, then the catheter can achieve desired flexibility and kink resistance, but the structure becomes more complex
Solution Approach 1:
The outer jacket is segmented into multiple layers with multiple segments per layer, allowing different durometers to be strategically placed throughout the structure. This segmentation enables precise control over the durometer gradient to achieve optimal flexibility and kink resistance while maintaining a manageable manufacturing process through standardized segment designs.
Solution Approach 2:
Different segments within the outer jacket are assigned different durometers based on local requirements. The durometer varies locally across the catheter length and around the circumference, with stiffer segments positioned where kink resistance is needed and more flexible segments where navigation is required. This local differentiation optimizes performance without requiring complete redesign of the entire structure.
3Reliability
If transition portions of adjacent segments overlap to produce gradual durometer change, then buckling is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The outer jacket is constructed from discrete segments that can be independently manufactured and then assembled. This segmentation allows for standardized production of individual segments with controlled durometers, reducing the overall manufacturing precision requirements compared to forming a continuous complex structure. The segments are designed with standardized interfaces that facilitate precise assembly while maintaining the desired gradual durometer transitions.
Solution Approach 2:
The durometer parameter is systematically varied across the outer jacket structure through the arrangement of segments with different material properties or wall thicknesses. By controlling the durometer gradient parameter through segment selection and arrangement rather than continuous material variation, the manufacturing process achieves the necessary transition smoothness with more manageable precision requirements.
Data Source
AI summary
In some examples, a catheter includes an elongated body defining a longitudinal axis and including an outer jacket. A portion of the outer jacket includes a first layer and a second layer overlying the first layer. The first layer includes a first segment and a second segment longitudinally adjacent to the first segment. The second layer includes a third segment and a fourth segment longitudinally adjacent to the third segment. Each segment includes a transition portion that is not continuous parallel to the longitudinal axis and a core portion that is continuous parallel to the longitudinal axis. A core portion of the second segment overlaps transition portions of the third and fourth segments radially from the longitudinal axis, while a core portion of the third segment overlaps transition portions of the first and second segments radially from the longitudinal axis.