Implantable Lead Transition Seal for Fluid Ingress Prevention
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Solution Overview
Problem
Current neuro stimulation leads with polyurethane lead bodies face issues with fluid ingress and potential electrical shorts when bent, due to exposure at transition areas between the lead body and stiff electrodes, leading to corrosion and malfunction.
Innovation Solution
A low-profile neuro stimulation lead with a softer transition component made from silicone, which complies with the lead body's bending, maintaining a fluid seal and preventing exposure of internal conductors, formed from a polyurethane lead body with a harder durometer than the transition components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a polyurethane lead body with higher durometer is used, then the lead body provides better structural support and abrasion resistance, but the transition areas between the lead body and electrodes expose internal conductors when bent, allowing fluid ingress
Solution Approach 1:
The patent applies local quality by transitioning from a harder polyurethane lead body to a softer transition component at the critical transition area. This localized change in material properties allows the transition component to conform and seal around the electrodes during bending, while the main lead body maintains its structural support and abrasion resistance.
Solution Approach 2:
The patent uses composite materials by combining polyurethane for the lead body with a softer material (such as silicone or ethylene vinyl acetate) for the transition component. This composite structure leverages the advantages of both materials: the polyurethane provides strength and abrasion resistance, while the softer transition component provides sealing compliance at the electrode interfaces.
2Strength
If a stiffer electrode structure is used, then the electrodes maintain their electrical integrity, but the transition areas between the lead body and electrodes create exposure risks when the lead is bent
Solution Approach 1:
The softer transition component acts as an intermediary between the stiff electrodes and the flexible lead body. During bending, this intermediary material deforms to maintain continuous coverage over the electrode transitions, preventing fluid from reaching the electrical connections while allowing the electrodes to maintain their structural integrity.
Solution Approach 2:
The softer transition component provides beforehand cushioning by being positioned in advance at the transition areas where bending-induced exposure would occur. This pre-positioned compliant material absorbs the mechanical stress of bending before it can cause exposure of the electrical connections, thereby preventing fluid ingress and corrosion.
3Reliability
If the lead body material is made softer to improve compliance, then sealing at transition areas improves, but the lead body loses abrasion resistance and structural integrity
Solution Approach 1:
The patent segments the lead body into distinct functional zones: a harder polyurethane section for the main lead body that requires abrasion resistance and structural integrity, and a softer transition component section at the electrode interfaces that requires compliance for sealing. This segmentation allows each segment to be optimized for its specific function without compromising the other.
Solution Approach 2:
The patent applies local quality by making only the transition areas softer while keeping the main lead body material harder. This localized softening at the transition components provides the necessary compliance for sealing without reducing the overall abrasion resistance and structural integrity of the lead body.
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 effectively seals the transition areas between the lead body and electrodes, preventing fluid ingress and electrical shorts, ensuring long-term functionality and reliability of the stimulation system.
Implementation Method 1
A low-profile neuro stimulation lead with a softer transition component made from silicone, which complies with the lead body's bending
Data Source
AI summary
An implantable stimulation lead is disclosed that includes an elongated lead body having opposed proximal and distal end portions, the lead body being formed from a material having at least one circumferential seal region associated with the distal end portion thereof within which a cylindrical electrode is positioned, the seal region being formed from at least one transition component made from a material that is softer than the material from which the lead body is formed.