Intervertebral Disk Prosthesis With O-Ring Damping
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Solution Overview
Problem
Existing intervertebral disk prostheses, particularly for cervical vertebrae, fail to perfectly replicate natural movements and suffer from rapid wear of articular surfaces, leading to undesirable particle diffusion and a high risk of intermediate element expulsion.
Innovation Solution
The prosthesis features two independent portions with an O-ring in an elastically deformable material, providing dual-directional damping during movements, and specific articular surface geometries to mimic natural vertebral movements, reducing wear and the risk of intermediate element expulsion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing intervertebral disk prostheses are used to replace damaged disks, then the structural support function is provided, but the natural movements of vertebrae are not perfectly reproduced and rapid wear of articular surfaces occurs
Solution Approach 1:
The prosthesis is divided into three separate elements: two flattened elements that articulate with the vertebrae and an intermediate sliding element. This segmentation allows each component to be optimized independently - the flattened elements provide stable vertebral articulation while the intermediate element accommodates movement, thereby reproducing natural vertebral movements without compromising the durability of the articular surfaces.
Solution Approach 2:
An intermediate sliding element is introduced between the two flattened elements. This intermediary component absorbs the wear and movement stresses, allowing the articular surfaces of the flattened elements to remain relatively stable and durable while still enabling the reproduction of natural vertebral movements through the sliding mechanism.
2Reliability
If the prosthesis comprises three elements with an intermediate sliding element, then the natural movements are better reproduced, but the risk of expulsion of the intermediate element increases
Solution Approach 1:
The retention function is extracted from the articular surfaces and transferred to dedicated retention structures - specifically, retention ledges are provided on the flattened elements that mechanically prevent expulsion of the intermediate sliding element. This separation allows the intermediate element to freely slide for movement reproduction while being securely retained by the ledge structures.
3Volume of moving object
If the articular surfaces have reduced dimensions for cervical vertebrae, then the prosthesis size is appropriate, but the wear of articular surfaces occurs more rapidly
Solution Approach 1:
The intermediate sliding element acts as a mediator that takes over the wear and movement accommodation function. This allows the articular surfaces of the flattened elements to be smaller (appropriate for cervical vertebrae) while the intermediate element, which handles the sliding movements, can be designed with sufficient surface area and appropriate material properties to resist wear.
4Device complexity
If the prosthesis comprises two elements with direct jointing, then the structure is simpler, but the natural movements of vertebrae are not perfectly reproduced
Solution Approach 1:
The prosthesis is segmented into three elements rather than two, with the intermediate sliding element providing a dedicated mechanism for reproducing natural vertebral movements. This additional segmentation enables more accurate movement reproduction while keeping each individual component relatively simple in design.
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
The solution effectively reproduces natural vertebral movements, reduces articular surface wear, and minimizes the risk of intermediate element expulsion, while simplifying assembly through retentive arched seats and biocompatible materials.
Implementation Method 1
an O-ring in an elastically deformable material, one of said seats is dimensioned in order to receive a radially outer portion of this ring while the other seat is dimensioned in order to receive a radially inner portion of this ring
Implementation Method 2
allows a damped movement of this second portion relatively to this first portion, and therefore globally a damped movement of a flattened element relatively to the other flattened element
Data Source
AI summary
A prosthesis comprises having two portions independent of each other, a first portion and a second portion, at least one of which includes an articular surface, said first portion and said second portion each comprising a circular seat delimited by an arched wall. An element of the prosthesis is an O-ring in an elastically deformable material, and one of said seats is dimensioned to receive a radially outer portion of this ring while the other seat is dimensioned to receive a radially inner portion of this ring.