Middle Ear Transducer Adhesive Pad Design

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Solution Overview

Problem

The existing methods for implanting a floating mass transducer (FMT) in the middle ear face challenges such as difficult handling and manipulation due to small size, incorrect placement, damage risk, and inadequate adhesive bonding between the FMT and coupling cap, leading to alignment issues and unwanted damping of mechanical stimulation signals.

Innovation Solution

A middle ear transducer arrangement featuring an elongated shape with a transducer adhesive feature and a coupling cap with a coupling adhesive feature, allowing for controlled and predictable adhesive application using heat and reduced air pressure to ensure distortion-free coupling without adhesive material on the drive surfaces, promoting self-alignment and secure bonding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If adhesive material is applied to bond the FMT and coupling cap, then bonding strength is improved, but adhesive material may contaminate the drive surfaces causing signal distortion

Engineering Contradiction:
Improvebonding strengthVSAvoidalignment precision
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The bonding interface is segmented into distinct functional zones: adhesive application zones (rings or patterns) separated from drive surfaces by adhesive-free zones. This segmentation prevents adhesive contamination of drive surfaces while maintaining bonding strength through controlled adhesive placement in concentric rings or radial patterns.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the bonding interface have different properties: adhesive-free zones maintain smooth, contamination-free surfaces for optimal mechanical signal transmission, while adhesive zones provide bonding strength. The drive surfaces have local quality optimized for signal coupling, while bonding zones have properties optimized for adhesion.

Inventive Principle:
Principle #3Local quality

2Volume of moving object

If the FMT and coupling cap are made small for minimally invasive implantation, then implantation trauma is reduced, but handling and manipulation difficulty increases

Engineering Contradiction:
Improvedevice sizeVSAvoidhandling ease
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The coupling cap incorporates protrusions that extend axially beyond the FMT housing, adding dimensional leverage points for surgical tools. This dimensional extension provides mechanical advantage for handling and alignment without increasing the radial footprint that would increase implantation trauma.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

Surgical alignment tools with corresponding recesses act as intermediaries during implantation. These tools engage with the coupling cap protrusions to provide precise alignment and secure holding during the bonding process, then are removed after bonding completes, leaving the compact device in place.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If adhesive material is used to secure the coupling cap, then bonding reliability is improved, but adhesive evaporation time and surgical complexity increase

Engineering Contradiction:
Improvebonding reliabilityVSAvoidsurgical time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The dilutant evaporation step is extracted and eliminated from the surgical process. Adhesive compositions are used that do not require dilutant evaporation, allowing immediate bonding after application and eliminating the time-consuming evaporation wait period while maintaining bonding reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The adhesive formulation parameters are changed to eliminate the need for dilutant evaporation. Adhesive compositions are selected or formulated to provide adequate viscosity and bonding performance without requiring solvent evaporation, fundamentally changing the adhesive application parameters to suit surgical time constraints.

Inventive Principle:
Principle #35Parameter changes

4Strength

If adhesive material is applied between FMT and coupling cap, then bonding strength is improved, but unwanted damping of mechanical signals occurs

Engineering Contradiction:
Improvebonding strengthVSAvoidsignal damping
Core Design Contradiction:
StrengthVSLoss of energy

Solution Approach 1:

The bonding interface is segmented into adhesive-free zones on the drive surfaces that directly transmit mechanical signals without adhesive interference, and adhesive zones that provide bonding strength. This segmentation allows mechanical signals to pass through the adhesive-free zones undamped while maintaining secure bonding through the adhesive zones.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Adhesive material is extracted from the drive surface areas where mechanical signal transmission occurs. By removing adhesive from these critical signal paths and confining it to peripheral bonding zones, the harmful damping effect is eliminated while preserving bonding functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

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 solution enables reliable, distortion-free coupling of mechanical stimulation signals with predictable adhesive bonding, reducing surgical complexity and avoiding unwanted damping, thus improving the precision and efficiency of FMT implantation.

Implementation Method 1

The adhesive material may be heated to a temperature sufficient to evaporate a dilutant of the adhesive material and/or reduce air pressure around the middle ear transducer arrangement to a pressure lower than atmospheric pressure.

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP3011760B1Middle ear transducer with biocompatible implantable adhesive pad
Publication Date: 2019.05.22 MED EL ELEKTROMEDIZINISCHE GERAETE GMBH
  • EP3011760B1 patent drawingFigure 1
  • EP3011760B1 patent drawingFigure 2A~2B
  • EP3011760B1 patent drawingFigure 3

AI summary

An implantable transducer converts an electrical stimulation signal into a corresponding mechanical stimulation signal. The transducer has an elongated shape with a transducer end face having a transducer drive surface adapted to produce the mechanical stimulation signal, and a transducer adhesive feature adapted to intra-operatively receive adhesive material. A separate coupling cap has a coupling end face with a coupling adhesive feature adapted to engage the transducer adhesive feature with the adhesive material and a coupling drive surface adapted for distortion-free coupling of the mechanical stimulation signal from the transducer drive surface to the coupling cap. A signal delivery surface of the coupling cap delivers the mechanical stimulation signal to an adjacent cochlear surface for sensation as sound.