Segmented Neurostimulation Lead Fabrication via Ring and Hypotube Welding
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Solution Overview
Problem
Deep brain stimulation leads with segmented electrodes are challenging to fabricate due to their small size, requiring precise control of electrical fields to avoid undesired tissue stimulation and side effects, while conventional leads with fully circumscribing electrodes are difficult to manufacture and secure effectively.
Innovation Solution
A method involving the use of ring components and hypotubes in a mold to form segmented electrodes, with welding, insulative material filling, and a pre-molded frame to maintain angular positions, along with different hypotube lengths for correct connection, and an insulative coating for mechanical and electrical integration, facilitating precise control of the electrical field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If segmented electrodes are used to precisely control electrical fields and avoid undesired tissue stimulation, then stimulation precision is improved, but manufacturing complexity increases due to the small size and precise positioning requirements
Solution Approach 1:
The electrode is divided into multiple segmented contacts (e.g., four segments) around the lead body, allowing independent selection and combination of segments to precisely control the electrical field distribution. This segmentation enables targeted stimulation of specific neural pathways while avoiding adjacent tissue, directly improving stimulation precision without requiring a completely new electrode architecture.
Solution Approach 2:
The segmented electrodes are integrated within a multi-layer insulative structure where inner insulative material is nested between the electrode segments and the outer insulative material. This nesting approach consolidates multiple functional layers (electrode segments, insulative materials, adhesive layers) into a compact integrated unit, reducing manufacturing complexity despite the increased precision requirements.
2Ease of manufacture
If conventional fully circumscribing electrodes are used, then manufacturing is simpler, but control of electrical field distribution and avoidance of undesired tissue stimulation is reduced
Solution Approach 1:
Instead of a uniform continuous electrode, the invention applies local quality by making the electrode segmented with discrete contacts at specific angular positions. Each segment can be independently activated to create localized electrical fields in specific directions, enabling precise control of field distribution while maintaining manufacturing feasibility through modular construction.
Solution Approach 2:
The electrode design transitions from a one-dimensional linear electrode to a two-dimensional segmented arrangement around the circumference of the lead body. This dimensional change allows control of electrical field distribution in multiple spatial directions (azimuthal and radial), significantly improving electrical field control precision while using standard manufacturing techniques for creating segmented structures.
3Measurement precision
If segmented electrodes with limited angular range are used, then electrical field control is improved, but the size and positioning precision requirements increase
Solution Approach 1:
The segmented electrode structure is pre-formed during the molding process with insulative material precisely positioned between segments before final assembly. This preliminary formation of the segmented structure with integrated insulative layers eliminates the need for post-manufacturing positioning adjustments, maintaining high electrical field control precision while reducing final assembly precision requirements.
Solution Approach 2:
The electrode assembly uses composite construction with conductive electrode segments combined with insulative materials (such as PEEK or other biocompatible polymers) that are molded together as an integrated structure. This composite approach provides both the conductive pathways for precise electrical field control and the insulative barriers that define segment boundaries, achieving high precision without requiring separate positioning steps.
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
Enables the precise control of electrical fields for deep brain stimulation, reducing undesired side effects by allowing selective stimulation of targeted neural tissue while avoiding other tissue, and ensuring the stability and functionality of the neurostimulation lead for long-term implantation.
Implementation Method 1
The hypotubes may be welded to the electrodes before placement within a mold for an injection molding process
Implementation Method 2
The molding process fills the interstitial spaces with suitable insulative material
Implementation Method 3
an insulative coating for mechanical and electrical integration
Data Source
AI summary
A method for fabricating a neurostimulation stimulation lead includes providing a plurality of ring components and hypotubes. An insulative coating is disposed on at least one of (i) inner surfaces of the ring components or (ii) the hypotubes. The method includes welding the hypotubes to the inner surfaces of the ring components, and molding an insulative material to fill interstitial spaces between the ring components and the hypotubes that are welded to form a stimulation tip component of the stimulation lead. The method includes forming segmented electrodes from the ring components after performing the molding.