Segmented Catheter Strengthening Element for Torque and EMI Shielding
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Solution Overview
Problem
Catheter assemblies for medical introducer devices face challenges such as kinking, electromagnetic interference, and heating issues due to continuous metal strengthening elements, which are unsuitable for deploying measurement instruments during imaging.
Innovation Solution
A catheter strengthening element with metallic members arranged in sections, interconnected by non-conductive coupling members to form a unitary structure that provides torque and electromagnetic shielding without acting as an antenna, reducing heat generation and maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If continuous metal strengthening elements are used in catheters, then the catheter gains strength and resistance to kinking, but it acts as an antenna causing electromagnetic interference and heating during imaging
Solution Approach 1:
The continuous metal strengthening element is divided into multiple discrete metallic segments spaced along the catheter length. Each segment is shorter than 1/4 wavelength of typical imaging frequencies, preventing antenna resonance while maintaining collective structural support. The segments are interconnected by non-conductive elements that electrically isolate them, breaking the continuous conductive path that causes electromagnetic interference.
2Stability of the object's composition
If metal strengthening elements are used to prevent kinking, then the catheter maintains structural integrity, but heating occurs due to induced currents during imaging
Solution Approach 1:
The metal strengthening element is segmented into discrete sections separated by non-conductive interconnects. This segmentation interrupts the continuous conductive path, preventing formation of large eddy currents during imaging that cause heating. Each small metallic segment induces minimal currents independently, dramatically reducing overall temperature rise while maintaining structural support.
Solution Approach 2:
Non-conductive interconnect elements are introduced between metallic segments to mediate the structural connection while providing electrical isolation. These intermediaries allow mechanical torque and positional transmission between segments while blocking electromagnetic current flow, thereby preventing heat generation from induced currents during imaging procedures.
3Force
If metal strengthening elements are used to provide torque, then the catheter maintains trackability, but the continuous metal structure disrupts measuring devices
Solution Approach 1:
The continuous metal tube is segmented into discrete metallic sections connected by non-conductive elements. Each segment can transmit torque locally, and the cumulative effect along the catheter provides sufficient torque transmission for trackability. The segmentation eliminates the antenna effect that disrupts measuring devices, as each short segment operates below resonant frequencies.
Solution Approach 2:
Non-conductive interconnects serve as mediators that transmit mechanical torque between metallic segments while providing electrical isolation. These intermediaries allow the catheter to maintain flexibility and torque transmission capabilities needed for navigation while preventing electromagnetic interference with sensitive measuring devices carried on the catheter.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution ensures the catheter assembly remains flexible and strong, preventing kinking while minimizing electromagnetic interference and heat generation, making it safe for deploying measurement instruments during imaging.
Implementation Method 1
the strengthening members being coupled together by at least one non-conductive coupling member
Implementation Method 2
the preferred structures disclosed herein provide individual small sections of metallic strengthening members which are interconnected to one another in such a manner that torque can be transmitted from one member to the other and which is able to act as a shield to electromagnetic waves without acting as an aerial
Data Source
AI summary
A catheter (40) or sheath (14) is provided with a strengthening element (30) embedded within the walls of the catheter (40). The strengthening element (30) is formed of a plurality of short strengthening members (32) arranged in longitudinally overlapping manner but which are radially spaced from one another and fixed to one another by annular coupling elements (36). The strengthening element (32) is made of a metal or metallic material, whereas the coupling elements (36) are made of a non-conductive material. The coupling elements (36) prevent electrical conduction through the length of the catheter (40) but retain a strengthening structure which provides torque strength and kink resistance. The short sections of conductive strengthening members (32) provide shielding of electromagnetic waves but prevent the strengthening element (30) acting as an aerial.