Composite Intervertebral Disc with Domed Articulation
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Solution Overview
Problem
Existing artificial spinal discs face issues with excessive wear debris due to point contact and limited motion capabilities, which can lead to reduced durability and ineffective pain management for low back pain.
Innovation Solution
A motion restoring intervertebral device with two components, where one component features a primary hard/stiff material for articulating surfaces and a secondary softer material for bone buttressing, allowing controlled rotation and translation, and incorporating a thin coating for enhanced bone attachment, reducing stress shielding and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If point contact articulating surfaces are used, then the device structure is simple, but excessive wear debris is generated reducing durability
Solution Approach 1:
The patent employs composite materials by combining a hard articulating surface material (such as ceramic or metal) with a softer polymeric outer section. The hard inner section provides wear-resistant articulating surfaces, while the softer outer polymeric section reduces stress concentration and distributes loads, thereby reducing wear debris generation and improving overall durability of the intervertebral device.
Solution Approach 2:
The patent applies local quality by having different material properties in different sections of the device. The inner articulating surfaces are made of hard material for low wear, while the outer section is made of softer polymeric material for stress distribution and bone compatibility. This localized differentiation of material properties optimizes both wear resistance and durability.
2Reliability
If hard material is used for articulating surfaces, then wear resistance is improved, but stress shielding of bone occurs
Solution Approach 1:
The patent uses composite materials to combine the wear resistance of hard articulating surfaces with the stress-distributing properties of softer polymeric outer sections. The polymeric material has a lower modulus of elasticity that is more compliant to bone, reducing stress shielding while the hard inner core maintains wear resistance at the articulating interfaces.
Solution Approach 2:
The patent applies local quality by making only the articulating surfaces hard for wear resistance, while the outer section and bone-contacting surfaces are made of softer polymeric material that better matches bone mechanics, thereby reducing stress shielding at the bone-implant interface.
3Ease of manufacture
If multiple interconnected parts are used, then ease of manufacture is improved, but micro-motion and wear increase
Solution Approach 1:
The patent merges multiple functions into a single integrated component. The inner hard articulating section and outer polymeric section are combined into one monolithic unit that can be manufactured as a single piece, eliminating micro-motion between separate parts and reducing wear at interfaces, while maintaining ease of manufacture through integrated 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 device provides improved durability and reduced wear by distributing forces evenly, enhancing the lifespan of the prosthesis and facilitating better bone integration, while allowing controlled motion and unobscured imaging of surrounding tissues.
Implementation Method 1
These polymers reduce stress shielding by more evenly distributing the forces or load from the articulating surfaces to the respective bone interface end thereby enhance the life of the prosthesis.
Implementation Method 2
The inner section, defining the articulating surface, is made of a primary relatively hard/stiff material such as ceramic, cobalt chromium, or other hard, stiff bio-compatible material for inhibiting the wear between the articulating surfaces.
Implementation Method 3
the bone buttressing surface to have a very thin coating or layer of a bone-on growth attachment friendly material, such as titanium, calcium phosphate or hydroxyapatite thereon
Data Source
AI summary
A motion restoring intervertebral device includes first and second articulating components positioned between adjacent vertebrae with the articulating surface of the first component being formed by a circular domed convex projection having a first radius. The articulating surface of the second component is formed by a generally concave recess having the first radius in the medial-lateral direction and a second larger sweeping radius in the interior-posterior direction so that the components are capable of rotating against each other in all directions and translate against each other in the anterior-posterior direction, whereby translation away from the center of the first radius will produce device and joint distraction to limit excessive translation.