Standalone Flexure-Based Interbody Fusion Implant for Physiological Motion
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Solution Overview
Problem
Existing spinal implants face challenges in providing both stability and flexibility, leading to issues like adjacent level degeneration, wear debris, and material degradation, while failing to match the physiological stiffness in all planes of motion.
Innovation Solution
The development of a flexure-based interbody implant with tension-based flexure assemblies between endplates, designed to provide stability and flexibility along multiple axes, including flexion/extension, lateral bending, and torsion, using components that are configured to withstand compressive forces by converting them into tensile forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a rigid connection is provided between adjacent vertebral bodies to restore spinal stability, then spinal stability is improved, but hypermobility at adjacent spinal segments occurs leading to adjacent level degeneration
Solution Approach 1:
The patent changes the mechanical parameters of the interbody device by incorporating flexures that provide controlled flexibility in specific directions while maintaining rigidity in others. The device transitions from a completely rigid structure to one with adjustable stiffness characteristics, allowing it to maintain spinal stability without creating hypermobility at adjacent levels.
Solution Approach 2:
The patent introduces dynamic characteristics to the interbody device through flexures that allow controlled motion. The device can adapt its rigidity based on physiological loading conditions, providing stability when needed while permitting natural spinal movement to prevent adjacent level degeneration.
2Adaptability or versatility
If sliding components are used to provide motion at the operative level, then flexibility is improved, but wear debris is generated causing osteolysis and device instability
Solution Approach 1:
The patent replaces the sliding mechanical system with a flexure-based mechanism. Instead of components sliding against each other and generating wear debris, the invention uses elastic deformation of flexure elements to provide controlled motion, eliminating the wear problem entirely.
Solution Approach 2:
The patent employs flexures that function as flexible structural elements to provide motion. These thin, flexible components bend and deform elastically to allow physiological movement without the friction and wear associated with traditional sliding interfaces.
3Adaptability or versatility
If polymeric cores are used to provide stable motion, then flexibility is improved, but the devices fail to restore stability in all planes of motion and suffer from oxidation and fatigue
Solution Approach 1:
The patent uses composite construction combining metal endplates with flexure elements, providing both the strength and stability of metal and the flexibility needed for physiological motion. This composite approach overcomes the limitations of single-material polymeric cores that degrade through oxidation and fatigue.
Solution Approach 2:
The patent changes the material parameters by selecting materials with appropriate mechanical and chemical properties. The flexure elements are made from materials resistant to oxidation and fatigue while maintaining the necessary flexibility and motion characteristics.
4Stability of the object's composition
If the device is made too rigid to stabilize the spine, then spinal stability is improved, but flexibility in planes of motion is reduced causing hypermobility at adjacent levels
Solution Approach 1:
The patent applies local quality by making different parts of the device have different mechanical properties. The endplates remain rigid for stability, while the flexure elements provide localized flexibility in specific directions, allowing the device to simultaneously achieve both stability and adaptability.
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 implant achieves stability and flexibility matching physiological conditions, reducing the risk of adjacent level degeneration and wear debris, while maintaining structural integrity and minimizing damage to surrounding tissues.
Implementation Method 1
one or more flexure assemblies disposed between the endplates and configured to provide stability to the implant when a load is placed on the endplates
Data Source
AI summary
Systems and methods for providing a flexure-based standalone interbody fusion device are described. In some implementations, a flexure-based standalone interbody fusion device includes one or more endplates (e.g., a first endplate and a second endplate). In some implementations, the device includes a flexure assembly (e.g., disposed between the two endplates), which in some cases is configured to bear at least a portion of the load applied to the endplates. Some iterations of the flexure assembly include one or more flexures. In some cases, applying a compressive force to the endplates places tension on the flexure, thereby providing a device that is flexible and resistant to buckling and breaking. Additional implementations are described.