Medical Lead Conductor Isolation for Impedance and Electrode Alignment
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Solution Overview
Problem
Existing medical leads face challenges in achieving optimal impedance values and conductor isolation, which affects the efficacy of electrical stimulation therapies, particularly in complex electrode array geometries and high-density electrode configurations.
Innovation Solution
The use of conductor separation techniques, such as splines and heat shrink tubing, to electrically isolate conductors and improve impedance characteristics, allowing for better electrode alignment and assembly of leads with higher electrode densities, is implemented. This includes the placement of splines at both ends of the lead and the use of heat shrink tubing to relieve stress and enable injection molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conductor separation techniques such as splines and heat shrink tubing are used, then impedance values are enhanced and conductor isolation is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The lead is divided into multiple segments with conductors separated by insulating materials (splines and heat shrink tubing) at specific locations. This segmentation provides electrical isolation between adjacent conductors, enhancing impedance values and reducing interference while maintaining manageable device complexity through modular insulation placement.
Solution Approach 2:
Insulating materials (splines and heat shrink tubing) are introduced as intermediary elements between adjacent conductors. These intermediaries provide the necessary electrical isolation and mechanical separation, enabling improved impedance characteristics without requiring fundamental redesign of the lead structure.
2Manufacturing precision
If conductor separation techniques are implemented, then electrode alignment and isolation are improved, but manufacturing complexity increases
Solution Approach 1:
Splines and heat shrink tubing are pre-positioned along the lead conductors before final assembly. This preliminary placement of insulating elements establishes precise conductor spacing and alignment early in the manufacturing process, ensuring accurate electrode positioning while simplifying subsequent assembly steps.
Solution Approach 2:
Conductor separation is applied locally at specific positions along the lead rather than uniformly throughout. Splines and heat shrink tubing are placed at critical locations where electrical isolation and mechanical separation are most needed, achieving precise electrode alignment without adding complexity to entire conductor runs.
3Stability of the object's composition
If heat shrink tubing is used to relieve stress and enable injection molding, then lead variability is reduced, but manufacturing process complexity increases
Solution Approach 1:
Heat shrink tubing is applied beforehand to conductor assemblies to provide stress relief and mechanical protection. This pre-application of protective insulation cushions conductors against mechanical stresses during subsequent manufacturing steps, reducing lead variability and ensuring consistent performance while enabling injection molding operations.
Solution Approach 2:
The use of heat shrink tubing enables parameter changes in the manufacturing process, specifically allowing injection molding of lead components. The heat shrink material provides a flexible, conformable barrier that accommodates molding pressures and temperatures, reducing variability in final lead dimensions and properties while integrating smoothly into existing manufacturing workflows.
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 enhances impedance values, reduces lead variability, and facilitates the use of complex electrode array geometries, improving the control and precision of electrical stimulation therapies by ensuring better isolation and alignment of conductors and electrodes.
Implementation Method 1
heat shrink tubing may be provided over the transition of the proximal end of the spline and middle portion of the lead to relieve stress
Data Source
AI summary
In one example, a lead comprises a plurality of conductors, each conductor of the plurality of conductors comprising a conductor first end, a conductor second end, and a conductor intermediate portion therebetween, and a spline. The lead may include a first set of contacts and a second set of contracts electrically coupled with respective conductors of the plurality of conductors. The second set of contacts may include a plurality of inserts defining a plurality of apertures through which an end of respective conductors is disposed. Tire lead may further include an outer lead body disposed over at least the intermediate portion of the plurality of conductors.