Preloaded Ball-Joint Ossicular Prosthesis for Play-Free Vibration Transfer

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Solution Overview

Problem

Existing auditory ossicular prostheses face challenges in effectively transmitting mechanical vibrations from the eardrum to the inner ear while accommodating post-operative movements caused by scar tissue and the healing process, which can impair acousto-mechanical signal transmission.

Innovation Solution

The auditory ossicular prosthesis features a ball-and-socket joint with a preload mechanism, including a spring washer and snap elements, to ensure a play-free and inelastic arrangement of the ball head in the ball socket, allowing for efficient vibration transmission despite potential movements, using metal or ceramic components for minimal damping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a ball joint with elastic plastic ball socket is used, then the prosthesis can accommodate post-operative movements, but vibration transmission is impaired due to elasticity and play

Engineering Contradiction:
Improveaccommodation of post-operative movementsVSAvoidvibration transmission efficiency
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent changes the material parameter of the ball socket from elastic plastic to metal or ceramic, fundamentally altering its mechanical properties to be rigid and inelastic, thereby eliminating the damping effect while maintaining the ability to accommodate post-operative movements through the ball-and-socket joint design

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the elastic plastic ball socket with a preload mechanism consisting of a spring element and retaining element, substituting the traditional elastic accommodation mechanism with a controlled preload system that eliminates play while maintaining adaptability to tissue movements

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If a ball joint with play is used, then post-operative movements can be accommodated, but pressure peaks occur that impair acousto-mechanical signal transmission

Engineering Contradiction:
Improveaccommodation of tissue movementsVSAvoidpressure peaks during healing
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies a preload mechanism that pre-compresses the ball head against the ball socket before any tissue movement occurs, establishing a constant contact force that prevents pressure peaks during the healing process and accommodates tissue movements without impeding signal transmission

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces a preload element (spring element and retaining element) as an intermediary mechanism between the ball head and ball socket, which mediates the interaction by maintaining controlled contact pressure and eliminating harmful pressure peaks while allowing for tissue movement accommodation

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If metal or ceramic components are used in the ball joint, then vibration transmission is minimized, but manufacturing complexity increases

Engineering Contradiction:
Improvevibration transmission efficiencyVSAvoidmanufacturing of ball joint components
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs composite material strategies by combining metal or ceramic ball head and socket components with elastomeric or polymeric preload elements, creating a hybrid structure that achieves superior vibration transmission from the rigid components while the polymeric elements provide compliance and ease of assembly

Inventive Principle:
Principle #40Composite materials

4Reliability

If a preload mechanism is added to the ball joint, then play-free reception is achieved, but device complexity increases

Engineering Contradiction:
Improveplay-free ball head arrangementVSAvoidball joint structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the preload function with the ball joint assembly by integrating the spring element and retaining element directly into the ball head and socket structure, combining the positioning, retention, and preload functions into a unified mechanism that achieves play-free reception without excessive complexity

Inventive Principle:
Principle #5Merging (Combining)

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 ensures virtually lossless transmission of mechanical vibrations from the eardrum to the auditory ossicle or oval window, accommodating post-operative movements and maintaining effective acousto-mechanical signal transmission.

Implementation Method 1

The ball socket holds the ball head in a use position of the shaft with preload in both a radial and an axial direction of the shaft

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

For effective transmission of the vibrations from the ball socket to the ball head of the ball joint of the ossicular prosthesis according to the invention, a play-free and inelastic arrangement of the ball head in the ball socket in the longitudinal direction is therefore necessary

Methodology Applied
Scientific EffectVibration transmission: Vibration

Data Source

PatentEP4203850B1Ossicular prosthesis
Publication Date: 2025.09.24 MED EL ELEKTROMEDIZINISCHE GERAETE GMBH
  • EP4203850B1 patent drawingFigure 1~2
  • EP4203850B1 patent drawingFigure 3~4
  • EP4203850B1 patent drawingFigure 5~6

AI summary

The invention suggests preloading a ball joint (4) of an ossicular prosthesis (1) in a longitudinal direction of a shaft (7) of said ossicular prosthesis (1) by means of a disc-shaped preloading element (11), such that vibration transmission is almost loss-free.