Conductive Multi-Layer Polymer Catheter for AIMD Lead Shielding
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Solution Overview
Problem
Active implantable medical devices (AIMDs) experience interference from electromagnetic fields due to their lengthy conducting materials, which act as antennas, restricting patient access to diagnostic tools like MRI scanners.
Innovation Solution
A conductive multi-layer polymer catheter is disposed around the AIMD lead, comprising an outer conductive polymer layer and optional inner and insulating polymer layers, designed to distribute electromagnetic radiation along the lead, reducing the antenna effect and protecting the device from external fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If lengthy conducting materials are used for AIMD leads and extensions, then the device can be implanted at comfortable locations and deliver therapeutic pulses effectively, but the conducting materials act as antennas and become problematic when exposed to electromagnetic fields
Solution Approach 1:
A multi-layer polymer catheter is introduced as an intermediary component between the conducting lead materials and the electromagnetic fields. The catheter includes an outer conductive polymer layer that contacts body tissue and acts as a shield, while inner insulating polymer layers provide electrical insulation. This intermediary structure prevents direct interaction between the conducting materials and electromagnetic fields, resolving the antenna effect while preserving implantation flexibility.
Solution Approach 2:
The catheter is constructed from composite materials consisting of multiple polymer layers with different properties. The outer layer uses conductive polymers (such as polypyrrole, polythiophene, or polyaniline) to provide electromagnetic shielding, while inner layers use insulating polymers (such as polyurethane, silicone, or PEEK) for electrical insulation. This composite structure enables simultaneous achievement of electromagnetic field protection and electrical conductivity requirements.
2Object-affected harmful factors
If the conducting material is made shorter to reduce antenna effects, then electromagnetic field interference is reduced, but mechanical stress increases and can result in wire fractures
Solution Approach 1:
The multi-layer polymer catheter serves as a protective intermediary that allows the conducting materials to maintain their full length for mechanical reliability while preventing them from acting as antennas. The outer conductive layer absorbs and redistributes electromagnetic energy along the catheter surface, preventing concentration at the lead tips, thus eliminating the antenna effect without requiring shortening of the conducting materials.
3Object-affected harmful factors
If conventional shielding materials are used to protect against electromagnetic fields, then electromagnetic interference is reduced, but the device complexity and surgical procedure complexity increase
Solution Approach 1:
The patent employs flexible thin-film polymer layers instead of bulky conventional shielding materials. The catheter can be collapsed into a compact form for implantation and then expands to surround the lead. This thin-film approach provides effective electromagnetic shielding while minimizing device complexity and surgical procedure complexity, as the flexible nature allows easy positioning and adaptation to the lead geometry.
4Reliability
If patients avoid strong electromagnetic fields to prevent interference, then device reliability is maintained, but access to important diagnostic tools like MRI scanners is restricted
Solution Approach 1:
The outer conductive polymer layer of the catheter converts the previously harmful electromagnetic fields into a beneficial shielding effect. By contacting body tissue, the conductive layer creates a Faraday cage effect that redistributes electromagnetic energy, protecting the internal conducting materials from interference. This allows patients to safely undergo MRI scans and other electromagnetic diagnostic procedures while maintaining AIMD reliability.
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 multi-layer polymer catheter effectively shields AIMD leads and extensions from electromagnetic radiation, preventing unwanted interactions and ensuring safer use of AIMDs in environments with electromagnetic fields.
Implementation Method 1
designed to distribute electromagnetic radiation along the lead, reducing the antenna effect and protecting the device from external fields
Data Source
AI summary
An active implantable medical device (AIMD) lead implanted into a patient's body may include at least one conductive filer electrically coupled to a distal electrode and a polymer jacket for insulating the conductive filer. A conductive multi-layer polymer catheter may be disposed around an outside of the insulating polymer jacket to reduce, or entirely eliminate, the conductive filer's exposure to electromagnetic radiation.