Ossicular Prosthesis In-Situ Length Adjustment via Radial Web Elements

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Solution Overview

Problem

Existing ossicular prostheses face challenges in providing flexible length adjustment post-implantation, leading to displacement, pressure peaks, and insufficient ventilation, while requiring invasive surgical openings and complex mechanisms for length adjustment.

Innovation Solution

A design featuring web elements within the head plate plane that can be radially expanded or contracted to adjust length in situ, using a mechanism with locking devices and atraumatic ends, allowing for symmetrical elongation and compact, minimally invasive insertion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the connection between the head plate and the shaft is rigid, then the structural strength is improved, but pressure peaks occur between the edge of the head plate and the eardrum that can result in penetration or extrusion

Engineering Contradiction:
Improvestructural strengthVSAvoidpressure peaks causing penetration or extrusion
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The connecting element is designed with web elements that can dynamically change their configuration - spreading radially outward to shorten axial length or returning to a more linear arrangement. This dynamic adaptability allows the prosthesis to adjust to postoperative movements of the eardrum and ossicles, distributing forces more evenly and avoiding pressure peaks that would occur with a rigid connection.

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If the prosthesis has a fixed length, then the manufacturing precision is improved, but the prosthesis cannot adapt to varying anatomical conditions and may be displaced during healing

Engineering Contradiction:
Improvefixed length precisionVSAvoidadaptation to anatomical variations and healing movements
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The web elements provide dynamic length adjustment capability, allowing the prosthesis to adapt its axial length in response to varying anatomical conditions and postoperative healing movements. The web elements can spread to shorten the prosthesis or return to a more extended configuration, providing continuous adaptability while maintaining manufacturing precision for the base structure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The prosthesis utilizes parameter changes in the web elements - specifically their radial position and orientation - to adjust the effective length of the connecting element. By changing the configuration parameter (radial spread) of the web elements, the prosthesis can adapt to different anatomical conditions without requiring multiple fixed-length implants.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If complex mechanisms are used for length adjustment, then the adaptability is improved, but the device complexity increases and invasive surgical openings are required

Engineering Contradiction:
Improvelength adjustment capabilityVSAvoidmechanism complexity and surgical invasiveness
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The web elements are designed as thin, flexible structural components that can be spread radially outward like an umbrella or accordion. This flexible membrane approach provides length adjustment capability without complex mechanical mechanisms - the web elements simply flex and spread to change the effective length, reducing device complexity and allowing for minimally invasive surgical insertion.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The web elements utilize a dimensional transformation approach - they are arranged in a collapsed or compressed state during insertion (minimizing profile) and then can be spread outward in the radial dimension to achieve length adjustment. This dimensional change strategy allows for simple, minimally invasive insertion while providing full length adjustment capability without complex mechanisms.

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

Data Source

PatentEP4292568B1Length-adjustable ossicular prosthesis with in-situ elongation out of head plate
Publication Date: 2025.08.06 HEINZ KURZ GMBH
  • EP4292568B1 patent drawingFigure 1a~1d
  • EP4292568B1 patent drawingFigure 2a~2c
  • EP4292568B1 patent drawingFigure 3~4

AI summary

An ossicular prosthesis (10) comprising a first fastening element (11) designed as a flat head plate for mechanical attachment to the tympanic membrane and a second fastening element (12) for connection with a link of the ossicular chain, as well as a connecting element (13) that connects the fastening elements in a sound-conducting manner and which has bridge elements (14) that can be spread radially outwards from the longitudinal axis and thereby shorten the axial length of the ossicular prosthesis, is characterized in that the bridge elements open directly at one end into coupling areas (15) of the first fastening element within the plane of the head plate and are movably but permanently connected to them, and that all bridge elements open at the other end into a coupling element (16) which is rigidly connected to the second fastening element.that the bridge elements, in an in-situ state, when a force is applied parallel to the longitudinal axis in the direction from the first to the second attachment element, each section by section assumes a position radially further from the longitudinal axis, thus shortening the functional length of the prosthesis, or increasing it when an antiparallel force is applied, and that the bridge elements maintain their radial position without force being applied. This allows for in-situ length adjustment with the prosthesis already placed in the middle ear.