Metallic Waveguide Cochlear Implant for Curved Nerve Alignment
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Solution Overview
Problem
The internal structure of the ear, particularly the small radius of curvature of the inner ear, poses challenges for guiding light for neural excitation, and aligning light sources with the auditory nerve is difficult, leading to inefficient light delivery and high energy consumption.
Innovation Solution
The use of metallic or photonic crystal waveguides to guide light around the small curvature of the ear, combined with a thermally deformable shape memory polymer (SMP) to maintain alignment with the auditory nerve, and a rolling/unrolling mechanism for controlled device insertion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If optical fibers are used to guide light into the ear, then light guidance is simplified, but light is lost due to high curvature radius requirements (cannot be bent below 5-10 mm) while the cochlea has a radius of curvature as low as 2 mm
Solution Approach 1:
The patent introduces a metallic waveguide as an intermediary medium between the light source and the auditory nerve. This metallic waveguide can be bent with a radius of curvature as small as 2 mm, overcoming the limitation of optical fibers that require minimum bending radii of 5-10 mm. The metallic waveguide serves as a mediator that adapts to the tight curvature of the cochlea while maintaining light guidance capability.
Solution Approach 2:
The patent changes the material parameter of the waveguide from optical fiber (silica-based) to metallic material. This parameter change enables the waveguide to withstand high curvature radii (down to 2 mm) without losing light guidance capability. The metallic waveguide's physical properties allow it to be bent sharply along the cochlear spiral while maintaining structural integrity and optical performance.
2Ease of operation
If light is delivered in a wide angular range without proper alignment, then the device is simpler to operate, but energy consumption increases significantly with reduced effectiveness
Solution Approach 1:
The patent employs a shape memory polymer (SMP) that automatically aligns the waveguide output with the auditory nerve through thermal deformation. The SMP is heated to a transition temperature, causing it to deform and position the waveguide tip precisely against the auditory nerve. This self-aligning mechanism eliminates the need for manual alignment procedures while ensuring optimal energy delivery efficiency.
Solution Approach 2:
The patent utilizes phase transition of the shape memory polymer from a low-temperature state to a high-temperature state. When heated above its transition temperature, the SMP undergoes a phase change that enables it to deform and assume a new shape. This phase transition allows the device to automatically position itself relative to the auditory nerve, achieving precise alignment without manual intervention and optimizing energy usage.
3Ease of manufacture
If a straight device is introduced into the spiraling cochlea, then manufacturing is simpler, but the device cannot be properly positioned in the curved environment
Solution Approach 1:
The patent transforms the device from a static straight configuration to a dynamic adaptable structure. The metallic waveguide is initially formed in a straight state for easy manufacturing, but upon introduction into the cochlea and application of local heating, the waveguide dynamically changes its shape to conform to the spiraling cochlear anatomy. This dynamic adaptability allows the device to navigate and position itself correctly within the curved environment.
Solution Approach 2:
The patent prepares the device in a pre-formed straight configuration for ease of manufacturing and initial insertion. The straight configuration serves as a preliminary state that facilitates device fabrication and initial placement. Subsequently, through thermal activation of the shape memory polymer, the device transitions to its final adapted shape, combining the advantages of simple manufacturing with effective cochlear adaptation.
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 approach enables efficient light delivery to the auditory nerve, increasing sensitivity to sound frequencies and reducing energy consumption by ensuring precise alignment and adaptability to the ear's shape.
Implementation Method 1
metallic waveguide or alternatively a photonic crystal waveguide, as will be described below
Implementation Method 2
the waveguide is maintained in place using a thermally deformable device, such as a thermally activated shape memory polymer (SMP) device that deforms under heating and maintains the light sources in place facing the auditory nerve
Implementation Method 3
metallic waveguide or alternatively a photonic crystal waveguide
Data Source
AI summary
A device for improving auditory acuity of a patient includes an array of waveguides for directing light to the auditory nerve. The array of waveguides is disposed in a flexible structure. A deployment mechanism deploys the structure such that the waveguides are aligned with the auditory nerve. The flexible structure has a shape that is changeable during introduction into the cochlea so as to adapt the shape to a shape of the cochlea.