Non-Planar Compliant Layer for Intervertebral Spacer Shear Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Intervertebral discs, when damaged due to degeneration or trauma, can collapse, leading to shear forces that existing intervertebral spacers with planar compliant layers are unable to effectively resist, resulting in potential disintegration and failure to provide adequate support and stability between vertebral bodies.
Innovation Solution
The use of intervertebral spacers with a non-planar compliant layer, made from biocompatible elastic or foamed materials like polyurethane or silicone, which provides built-in resistance to shear forces by engaging with upper and lower layers, offering varying shapes and configurations to accommodate bone grafts and enhance structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a planar compliant layer is used in intervertebral spacers, then the spacer structure is simple and easy to manufacture, but the spacer cannot effectively resist shear forces and may disintegrate
Solution Approach 1:
The patent applies curvature by transitioning from a planar compliant layer to a non-planar compliant layer with three-dimensional surface features. The non-planar layer includes protrusions, recesses, or other surface irregularities that engage with corresponding features on the upper and lower layers, creating mechanical interlocking that resists shear forces while maintaining structural integrity.
Solution Approach 2:
The patent employs composite material construction by combining the non-planar compliant layer with upper and lower layers of different materials. The compliant layer is made from a material with different mechanical properties (softer, more yielding) compared to the upper and lower layers, creating a composite structure that leverages the complementary properties of each material to achieve both compliance and shear resistance.
2Reliability
If a non-planar compliant layer is used, then shear force resistance is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the spacer into distinct functional layers: upper layer, non-planar compliant layer, and lower layer. Each layer can be manufactured separately using appropriate processes, then assembled together. The non-planar compliant layer may be segmented into multiple protrusions or recesses that can be formed through additive manufacturing or other specialized fabrication techniques, allowing complex geometries to be created modularly.
3Adaptability or versatility
If the compliant layer is made more yielding, then it can accommodate anatomical movements, but its resistance to shear forces may be reduced
Solution Approach 1:
The patent applies local quality by creating different surface characteristics in different regions of the compliant layer. The non-planar surface includes localized protrusions and recesses that provide mechanical engagement for shear resistance, while the overall material composition maintains yielding properties for anatomical movement. The complementary surfaces on upper and lower layers create localized engagement points that distribute shear forces while allowing global compression and movement.
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 non-planar compliant layer effectively resists shear forces, providing stability and support between vertebral bodies, reducing the risk of spacer disintegration and allowing for anatomical movements, thus addressing the limitations of planar compliant layers in existing spacers.
Implementation Method 1
The non-planar compliant layer may comprise an implantable, biocompatible elastic or foamed material that is more yielding than that of the upper layer and the lower layers
Data Source
AI summary
An intervertebral spacer having an upper layer, a lower layer and at least one non-planer compliant layer. The non-planer compliant layer is disposed between the lower layer and the upper layer and includes a portion that extends outside a lateral plane in which the compliant layer resides. The non-planar compliant layer made of a material that is more yielding than the upper layer and the lower layers, and may have a cross-section that is z-shaped, u-shaped, sinusoidal-shaped, zigzag shaped, etc.