Adjustable Ossicular Prosthesis with Resilient Joint
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Solution Overview
Problem
Existing ossicular prostheses face limitations in adjustable length and stability due to ambient pressure changes and anatomical variations, leading to potential dislodgement and poor sound conduction, especially in patients with small anatomical spacing.
Innovation Solution
An adjustable length ossicular prosthesis with a flexible silicone sleeve and a shaft having alternating cross-sectional portions, allowing incremental length adjustment and temporary angular displacement, providing a slip lock mechanism for stable retention and accommodating varying anatomical dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a flexible sleeve is used to allow length adjustment, then the prosthesis can be adjusted to accommodate anatomical variations, but the prosthesis becomes susceptible to dislodgement due to pressure changes
Solution Approach 1:
The prosthesis employs a dynamic retention mechanism where the shaft can move axially within the head through a flexible sleeve during implantation to adjust length, but then locks into discrete positions to provide stable retention. This dynamic system allows the prosthesis to adapt to anatomical variations while maintaining reliability against dislodgement through controlled movement and positioning.
2Adaptability or versatility
If the prosthesis is made adjustable in length, then it can accommodate different anatomical dimensions, but the device complexity increases
Solution Approach 1:
The prosthesis is segmented into distinct components: a head, a flexible sleeve, and a shaft with alternating enlarged and reduced cross-sectional portions. This segmentation allows for independent optimization of each component and simplifies the adjustment mechanism, as the shaft can be trimmed to different lengths while maintaining a relatively simple overall structure.
Solution Approach 2:
The prosthesis utilizes parameter changes in the shaft's cross-sectional dimensions, with alternating enlarged and reduced portions that engage with the flexible sleeve. This allows for discrete length adjustments and stable retention positions without requiring complex adjustment mechanisms, thereby reducing device complexity while maintaining adaptability.
3Adaptability or versatility
If the shaft is made plastically bendable to accommodate angulation, then the prosthesis can better fit anatomical variations, but the structural integrity may be compromised
Solution Approach 1:
The shaft exhibits local quality variations with alternating enlarged and reduced cross-sectional portions. The reduced portions provide flexibility for bending and angular accommodation, while the enlarged portions maintain structural integrity and provide stable engagement points with the flexible sleeve. This localized variation in properties allows the shaft to be plastically bendable where needed while maintaining overall strength.
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
Enables precise length adjustment down to 0.75 mm and resilient angular orientation, enhancing the prosthesis's stability and fit within the middle ear, reducing the risk of dislodgement and improving sound conduction across a range of anatomical configurations.
Implementation Method 1
The shaft diameter and sleeve throughbore are sized to each other such that the sleeve grips the shaft under static conditions but also permit the shaft to be moved axially therethrough
Implementation Method 2
A flexible sleeve is mounted within the head at the through opening... The shaft and sleeve throughbore preferably have corresponding structure that allows incremental discrete displacement relative to each other and subsequent retention
Data Source
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AI summary
An ossicular prosthesis is adjustable in length and temporarily and resiliently adjustable in angular orientation. The prosthesis includes a head for contacting a tympanic membrane, and a resilient sleeve is mounted within the head. An elongate shaft extends through the sleeve, and includes a distal end adapted to engage a footplate or stapes. The sleeve forms a resilient joint that allows the shaft to undergo an angular motion relative to the sleeve when subject to a non-axial force, and then subsequently return to its original position after the force is removed. The sleeve may also be longitudinally displaceable within the head of the prosthesis such that the shaft can undergo a damped linear motion. Also as a result of the arrangement of the sleeve, the prosthesis is adjustable to a very short length.