Welded Multi-Contact Electrodes for Dense Implantable Leads
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Solution Overview
Problem
Existing implantable stimulation devices face challenges in miniaturization and scalability due to one-to-one wiring requirements, which limit the number of electrodes and increase device size, manufacturing costs, and pose issues with MRI compatibility.
Innovation Solution
The development of implantable devices with a hermetically sealed enclosure and integrated feedthrough conductors, featuring a multi-contact electrode array with continuous conductive elements that are electrically isolated and welded to feedthrough conductors, allowing for a flexible substrate with increased electrode density and reduced wire count, and incorporating active circuitry along the lead body for improved MRI compatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If one-to-one wiring is used to connect electrodes to the device, then each electrode can be individually controlled, but the device size increases and the number of wires increases
Solution Approach 1:
Multiple discrete wire connections are merged into a single flexible substrate that carries multiple conductive elements. The substrate integrates multiple electrical pathways into one unified structure, reducing the number of separate wires and simplifying the connection between the device and multiple electrodes.
Solution Approach 2:
The connection structure transitions from one-dimensional wire connections to a two-dimensional flexible substrate with patterned conductive elements. This dimensional change allows multiple electrical pathways to be packed more efficiently, reducing overall complexity while maintaining individual electrode control capability.
2Adaptability or versatility
If the number of electrodes is increased to improve therapy, then therapeutic capability is enhanced, but device miniaturization becomes more difficult
Solution Approach 1:
A flexible substrate with thin-film conductive elements replaces bulky wire assemblies. This allows high-density electrode arrays to be implemented on a thin, flexible platform that can be integrated into a miniaturized device while maintaining the ability to control multiple electrodes independently.
Solution Approach 2:
The electrode connections are arranged in a two-dimensional pattern on the flexible substrate, allowing multiple electrodes to be connected within a smaller footprint. This spatial arrangement enables high electrode density without proportionally increasing device volume.
3Ease of manufacture
If traditional wiring is used, then manufacturing is simpler, but MRI compatibility is compromised due to wire stiffness and induced currents
Solution Approach 1:
The flexible substrate with thin conductive elements reduces loop area and stiffness compared to traditional wire assemblies. This minimizes induced currents during MRI procedures while maintaining manufacturability through established flexible circuit fabrication techniques.
Solution Approach 2:
The flexible substrate can dynamically conform to different positions and orientations during implantation and MRI procedures, reducing mechanical stress and induced currents. The flexibility allows the structure to adapt to changing conditions rather than maintaining a rigid configuration that generates harmful currents.
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
This design enables a more robust and scalable implantable device with higher electrode density, reduced off-target effects, and enhanced MRI compatibility by minimizing wire stiffness and surgical complexity, while maintaining biocompatibility and thermal stability.
Implementation Method 1
a plurality of welded couplings connecting at least one of the connection pads to at least one of the feedthrough conductors
Data Source
AI summary
An implantable device has a hermetically sealed enclosure, an electronic device within the hermetically sealed enclosure, and a plurality of feedthrough conductors in mechanical contact with the hermetically sealed enclosure and exposed outside of the hermetically sealed enclosure. The implantable device also has a flexible substrate with a plurality of therapy contacts, and a plurality of continuously conductive elements extending along the flexible substrate from the array of therapy contacts and terminating at a plurality of connection pads. Each of the continuously conductive element is integral with at least one therapy contact and at least one connection pad to electrically communicate the noted therapy contact(s) and the noted connection pad(s). The thickness of each continuously conductive element may be between about 5 and 190 microns. The implantable device also has a plurality of mechanical welded couplings that each couple at least one of the connection pads.