Hypoglossal Nerve Cuff Structure for Flexibility and Delamination Resistance
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Solution Overview
Problem
Nerve cuffs used for stimulating the hypoglossal nerve to treat obstructive sleep apnea are susceptible to delamination due to inadequate bonding between conductive and non-conductive layers, and lack flexibility, which can lead to fatigue and damage.
Innovation Solution
The nerve cuffs are designed with a cuff body having electrically conductive members spaced between layers, with strategically placed openings and flexible conductors connecting them, enhancing adhesion and flexibility to reduce delamination and fatigue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If electrically conductive members are laminated between non-conductive layers using adhesive, then the nerve cuff structure is formed, but the bond strength is insufficient leading to delamination
Solution Approach 1:
The conductive members are provided with crimp regions and rolled portions before assembly, which are then deformed during the crimping process to mechanically interlock with the non-conductive layers. This preliminary preparation of structural features enables strong mechanical bonding that prevents delamination during subsequent use and implantation.
Solution Approach 2:
The nerve cuff is constructed as a composite structure combining conductive members (such as platinum-iridium) with non-conductive layers (such as silicone or polyimide). The crimping process creates a mechanically interlocked composite where the deformed conductive members penetrate and anchor into the non-conductive material, achieving strong adhesion without relying solely on chemical adhesives.
2Strength
If the nerve cuff is made rigid to maintain structural integrity, then manufacturing is simplified, but flexibility is reduced causing fatigue and damage
Solution Approach 1:
The conductive members are divided into multiple discrete segments or contacts rather than being a single continuous rigid structure. Each contact can independently deform and flex, allowing the nerve cuff to bend and conform to the nerve while maintaining electrical connectivity through the flexible conductor system.
Solution Approach 2:
The non-conductive layers are designed as thin, flexible films (such as silicone or polyimide) that provide structural support while allowing bending and deformation. These thin film structures enable the nerve cuff to flex around the nerve without creating stress concentrations that would lead to fatigue or damage.
3Reliability
If the conductive members are made wide to improve electrical contact, then stimulation effectiveness increases, but the nerve cuff becomes less flexible
Solution Approach 1:
The electrical contact function is divided into multiple discrete conductive contacts rather than using a single wide conductive member. Each contact can be relatively narrow and flexible, yet collectively they provide sufficient electrical contact area for effective stimulation while maintaining the flexibility of the overall nerve cuff structure.
Solution Approach 2:
The conductive members are configured to extend in multiple dimensions, with some contacts extending in the width direction and others in the length direction. This multi-dimensional arrangement allows for adequate electrical contact surface area while keeping individual contact elements narrow and flexible, resolving the contradiction between contact width and flexibility.
Data Source
AI summary
An electrode that includes an elongate lead body and a nerve cuff. The nerve cuff may include a biologically compatible, elastic, electrically insulative cuff body configured to be circumferentially disposed around a nerve, first and second relatively wide electrically conductive contacts carried by the cuff body that are spaced from one another in the length direction and that extend in the width direction to such an extent that they extend completely around the cuff body inner lumen when the cuff body is in the pre-set furled shape, and a plurality of relatively narrow electrically conductive contacts carried by the cuff body that are spaced from one another in the width direction and are located between the first and second relatively wide electrically conductive contacts.