Spinal Disc Prosthesis Flexible Core Annulus Fibrosis Mimicry
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing spinal disc prostheses fail to reliably withstand application forces such as compression, shear, and torsion, leading to separation of rigid plates from the elastomeric material and stress on the disc body, resulting in potential failure.
Innovation Solution
The design incorporates a flexible core with compressible and biocompatible strands mimicking the Annulus Fibrosis, connecting two end disks that promote fusion with vertebrae and allow for natural translation, extension, and axial support, using materials like PEEK and various fiber configurations to enhance stability and compatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid plates are used in the disc prosthesis, then structural support is provided, but the rigid plates separate from the elastomeric material under application forces
Solution Approach 1:
The patent replaces the rigid plate-elastomeric material construction with a flexible membrane structure that has regions of different rigidity. The membrane includes a first region with higher rigidity for vertebral body engagement and a second region with lower rigidity for intervertebral disc engagement, eliminating plate separation issues while maintaining structural support.
2Adaptability or versatility
If elastomeric material is used for the disc body, then flexibility is provided, but the elastomeric body is squeezed out from between the two plates under compression forces
Solution Approach 1:
The flexible membrane structure with controlled rigidity regions prevents material extrusion by distributing compression forces across the membrane area rather than concentrating them on the elastomeric body. The membrane's structural integrity maintains containment while allowing necessary flexibility for disc function.
Solution Approach 2:
The membrane is constructed as a composite structure with regions of different rigidity, combining the benefits of structural support and flexibility in a single integrated component that resists extrusion under compression.
3Strength
If visco-elastic material is used for the prosthetic disc body, then cushioning is provided, but the disc body rotates excessively under torsion forces
Solution Approach 1:
The flexible membrane with differentiated rigidity regions provides torsional stability by distributing rotational forces across its structure. The higher rigidity region anchors the membrane to vertebral bodies, reducing excessive rotation while the overall flexible structure maintains cushioning capability.
4Ease of manufacture
If a single rigid structure is used for the disc prosthesis, then manufacturing is simplified, but the prosthesis cannot mimic natural spinal disc functionality
Solution Approach 1:
The membrane is designed with spatially varying rigidity properties, where different regions have different mechanical characteristics optimized for their specific functions. This allows the single-component structure to mimic the complex functionality of natural spinal discs while remaining manufacturable.
Solution Approach 2:
The membrane combines materials or structural configurations with different rigidity levels in a single integrated component, enabling both simplified manufacturing and natural movement simulation through the composite structure's differential mechanical properties.
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
This design provides a more reliable artificial spinal disc that mimics natural spinal disc functionality, reducing the risk of failure under application forces and promoting bone fusion, thus improving the longevity and effectiveness of the prosthetic.
Implementation Method 1
The flexible core is characterized by a plurality of compressible and/or flexible (pliant) strands extending between the upper and lower plates
Implementation Method 2
When a visco-elastic material is used for the prosthetic disc body between two plates, the application forces and their attendant problems are especially true
Implementation Method 3
Pliant strands extend substantially perpendicular to the first and second disks
Implementation Method 4
The strands are formed of a compressible and/or flexible, biocompatible material
Data Source
AI summary
A spine disc prosthesis mimics a natural human spine disc through use of a structure that duplicates a natural Annulus Fibrosis of the disc to provide translation, extension, flexion, and axial support in like manner to a natural disc. The present spine disc prosthesis achieves this through the use of a first and second disk connected to one another via a flexible annulus fibrosis structure. The flexible annulus fibrosis structure or core is characterized by a plurality of compressible (pliant) strands that are affixed to and extend between the first and second disks. The strands are preferably, but not necessarily, situated on and extend about an outer perimeter of inside surfaces of the two end disks so as to mimic natural contours of an annulus fibrosis of a natural spinal disc. The strands may be formed by various types of biocompatible fibers, braids, cords, bundles or the like and may have a hollow core or a solid core (e.g. PEEK [polyetheretherketone] cores/core strands may also be used). The strands may be situated on the vertical, crossed or in other configurations. The end disks may be formed as to promote fusion with adjoining vertebrae when implanted. The end plate may also include a keel and/or installation structure to allow for implanting the spine disc prosthesis.