Artificial Disc Replacement With Curved-Core Motion Guidance
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Solution Overview
Problem
Current artificial disc replacement (ADR) systems impede normal spinal movement, cause tissue scarring, and generate MRI artifacts due to metallic endplates, limiting motion range and complicating medical imaging.
Innovation Solution
An ADR device with a core member having varying curvature and a matrix member that prevents endplate contact, allowing natural motion and using non-metallic materials to reduce artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metallic endplates are used in current ADR systems, then the endplates can withstand high contact forces during flexion and extension, but they create unwanted visual artifacts during MRI imaging
Solution Approach 1:
The patent changes the material parameter of the endplates from metallic to non-metallic materials such as ceramic or carbon fiber reinforced polymer. This material substitution maintains the mechanical strength required to withstand contact forces while eliminating the magnetic interference that causes MRI artifacts, thereby resolving the contradiction between strength and MRI compatibility
Solution Approach 2:
The patent employs composite materials such as carbon fiber reinforced polymer for the endplates. These composite materials provide high strength-to-weight ratio and excellent mechanical properties comparable to metals, while being non-magnetic and MRI-compatible, thus resolving the contradiction between requiring high strength and avoiding MRI artifacts
2Ease of operation
If mobile cores are used in current ADR systems, then the cores can slide along endplates to allow motion, but they may become displaced from their intended range of motion due to tissue scarring
Solution Approach 1:
The patent employs a curved engaging surface on the core member that interfaces with a corresponding curved recess in the endplate. This curved geometry guides the core's movement along a predetermined arc-shaped path, ensuring that the core remains within its intended range of motion during flexion and extension, thereby preventing displacement caused by tissue scarring while maintaining full spinal mobility
Solution Approach 2:
The patent creates a dynamic interaction between the core and endplate through the curved engaging surface and recess. As the spine moves through flexion and extension, the core naturally follows the curved path defined by the geometry, adapting its position dynamically while remaining constrained within safe limits. This dynamic constraint system maintains reliability without impeding normal motion
3Ease of operation
If fixed central pivot points are used in current ADR systems, then the vertebrae can pivot during motion, but they prevent the vertebrae from translating during flexion
Solution Approach 1:
The patent replaces the fixed central pivot point with a curved engaging surface that allows the core to move along an arc-shaped path. This curved geometry enables both rotational pivoting and anterior-posterior translation of the vertebrae during flexion and extension, thereby restoring the full range of natural spinal motion that was previously restricted by fixed pivot mechanisms
Data Source
AI summary
An artificial disc replacement device, including a first endplate configured to be disposed against a first vertebra in a spine and a second endplate configured to be disposed against a second vertebra in the spine. The device further including a core member disposed between the first endplate and the second endplate, the core member having a curved engaging surface for engaging the first endplate. The device is configured to articulate between the core member and the first endplate in an anterior-posterior direction and the core member and the second endplate are configured to remain substantially fixed with respect to one another. As the artificial disc replacement device undergoes flexion, the central axis of the first endplate is also translated in an anterior direction. And the device is configured to articulate between the core member and the first endplate in a lateral direction without lateral translation.