Intervertebral Disk Prosthesis With Asymmetric Fluid Compartments
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Solution Overview
Problem
Existing intervertebral disk prostheses fail to provide a heterogeneous response to heterogeneous pressure, cannot withstand high pressures, and have inadequate deformation kinetics, often requiring invasive surgery and posing health risks due to metallic components.
Innovation Solution
A multilayered, deformable casing with asymmetrically distributed vertical walls and compartments filled with a non-toxic saline solution, allowing fluid circulation and pressure adaptation within specific time frames, and equipped with pressure sensors for monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If regular prosthesis with homogeneous compartments are used, then the structure is simple and easy to manufacture, but they cannot provide heterogeneous response to heterogeneous pressure and may damage the vertebrae
Solution Approach 1:
The inner cavity is partitioned by vertical walls into multiple cavity compartments (at least four) with asymmetric distribution - fewer and/or larger compartments in the posterior part and more/smaller compartments in the anterior part. This segmentation allows different regions to respond differently to pressure, providing heterogeneous response to heterogeneous pressure while maintaining structural organization
Solution Approach 2:
Different cavity compartments have different sizes and are distributed asymmetrically, with the posterior part having fewer and/or larger compartments and the anterior part having more and/or smaller compartments. This local differentiation enables each region to adapt to the specific pressure distribution it experiences, with larger posterior compartments handling higher compressive loads and anterior compartments managing tensile and shear forces
2Strength
If metallic structures are used for prosthesis, then the mechanical strength is high, but metallic structures form cations which are cancerogenic
Solution Approach 1:
The prosthesis uses a biocompatible polymer casing (such as polyurethane, polyethylene, or polyester) instead of metallic structures. While the material strength is lower than metal, the design compensates through the fluid-filled compartments and partition walls that distribute and withstand mechanical loads, eliminating the cancerogenic issue of metallic cations
Solution Approach 2:
The prosthesis combines biocompatible polymer materials (casing and partition walls) with a fluid filling (saline solution or gel). This composite structure provides both mechanical strength through the polymer framework and fluid pressure resistance, while avoiding the harmful effects of metallic materials
3Reliability
If prosthesis require belly surgery for insertion, then the prosthesis can be properly positioned, but the surgery becomes very expensive and requires two surgeons
Solution Approach 1:
The prosthesis uses a flexible, deformable casing that can be compressed to a smaller size for insertion through a less invasive approach. The waterproof multilayered structure allows the prosthesis to be collapsed during insertion and then expand to its functional shape once positioned, reducing surgical complexity while maintaining positioning accuracy
4Strength
If prosthesis use single-chamber design, then the structure is simple, but the deformation kinetics are not satisfactory and cannot withstand very high pressure
Solution Approach 1:
The single cavity is divided into multiple smaller cavity compartments (at least four) separated by partition walls. This segmentation allows the prosthesis to withstand very high pressures by distributing the load across multiple compartments and walls, while the asymmetric configuration (fewer/larger posterior compartments, more/smaller anterior compartments) optimizes the response to different pressure directions and magnitudes
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 provides a responsive, biocompatible prosthesis that mimics natural disk mechanics, withstands high pressures, and reduces surgical invasiveness while minimizing health risks, with wireless monitoring for proactive maintenance.
Implementation Method 1
the vertical walls comprise orifices and/or porous membranes configured to induce the saline solution to flow from one cavity compartment toward another upon heterogeneous application of a pressure comprised between 0.05 and 3 MPa
Implementation Method 2
the vertical walls comprise orifices and/or porous membranes configured to induce the saline solution to flow from one cavity compartment toward another
Implementation Method 3
external waterproof multilayered deformable casing surrounding a peripheral partition membrane delimiting an outer space and an inner cavity
Implementation Method 4
the nucleus can redistribute the pressure applied to the disk in all directions whereas the fibrous ring can withstand high compressive forces
Data Source
Figure 1~2
AI summary
Intervertebral disk prosthesis comprising an external waterproof multilayered deformable casing surrounding a peripheral partition membrane delimiting an outer space and an inner cavity, wherein the inner cavity is partitioned by vertical walls delimiting at least four cavity compartments configured to be filled with a non-toxic saline solution, and wherein the vertical walls comprise orifices and/or porous membranes configured to induce the saline solution to flow from one cavity compartment toward another upon heterogeneous application of a pressure comprised between 0.05 and 3 MPa in a duration comprised between 10 seconds and 60 minutes, and to revert back to its native compartment upon removal of said pressure in a duration comprised between 10 seconds and 180 minutes, and wherein the walls are distributed asymmetrically in the inner cavity so that a posterior part of the inner cavity comprises fewer and/or larger cavity compartments than an anterior part of the inner cavity.