Cochlear Implant Electrode Lead Asymmetric Cross-Section
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Solution Overview
Problem
Conventional cochlear implant electrode leads struggle to achieve optimal contact with the modiolar wall of the cochlea, leading to suboptimal electrical stimulation and potential damage due to uneven pressure distribution during insertion and implantation.
Innovation Solution
The electrode lead is designed with a cross-sectional shape having a greater height on the lateral side than the medial side, allowing it to curve and hug the modiolar wall, with a method involving a polymeric insulating material and molding process to create a precurved shape that maintains contact and distributes pressure effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrode lead is inserted into the cochlea to contact the modiolar wall, then electrical stimulation is achieved, but uneven pressure distribution causes potential damage and suboptimal stimulation
Solution Approach 1:
The electrode lead cross-section is designed with non-uniform thickness, being thinner on the medial side (facing the modiolar wall) and thicker on the lateral side. This local variation in geometry allows the lead to conform to the cochlear wall while distributing contact pressure more evenly, preventing both excessive pressure points and insufficient contact areas.
Solution Approach 2:
The carrier member cross-section employs an asymmetric design where the height from the transverse surface to the outer surface differs between the medial and lateral sides. This asymmetric geometry enables the lead to naturally curve and hug the modiolar wall, achieving optimal electrode contact while maintaining uniform pressure distribution through the varying thickness profile.
2Reliability
If the carrier member is molded with a pre-curved shape to hug the modiolar wall, then electrode contact is improved, but the lead stores elastic energy that may cause restoration forces
Solution Approach 1:
The cross-sectional thickness of the carrier member is varied along its length and across its width, creating a non-uniform geometry that reduces the overall elastic energy stored during bending. This parameter optimization allows the lead to achieve the necessary curvature for electrode contact while minimizing the restoration force that could compromise implant stability or cause discomfort.
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 enhances contact between electrode contacts and the cochlear wall, reducing pressure points and potential damage, while allowing for tailored curving forces to ensure consistent contact and improved electrical stimulation.
Implementation Method 1
filling the cavity including the sub-assembly with a polymeric insulating material, and curing the polymeric insulating material around the sub-assembly to form the carrier member
Implementation Method 2
When the array tip is straightened (for example by stylet or insertion tube), the tip stores elastic energy which exerts a force tending to restore the lead to its originally-molded curved shape
Data Source
AI summary
An electrode lead for insertion into a patient's cochlea includes a substantially solid elongate carrier member having lateral and medial sides and opposing transverse surfaces extending between outer surfaces of the lateral and medial sides, wherein the carrier member has a thickness between outer surfaces of the lateral and medial sides, and a plurality of electrodes disposed on or in the medial side. A height of the lateral side between the transverse surfaces is generally greater than a height of the medial side between the transverse surfaces, wherein each of the heights is approximately perpendicular to the thickness.