Spinal Implant Inner Core Elastomeric Shock Absorption
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Solution Overview
Problem
Current spinal implants for degenerative disc disease often limit range of motion and mobility due to metal-to-metal sliding and corrosion, leading to wear and debris issues, and fail to effectively absorb shock and resist compression forces.
Innovation Solution
A motion-preserving spinal implant design featuring a polymeric and elastomeric inner core with varying hardness, such as silicone, and a polyether ether ketone (PEEK) outer core with interlocking members, which reduces wear, enhances cushioning, and maintains spinal motion range by resisting compression, shear-compression, and torsion forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spinal fusion treatment is used to treat degenerative disc disease, then pain is alleviated, but range of motion and mobility are limited
Solution Approach 1:
The implant is divided into distinct functional segments: an inner core for shock absorption, an outer core for motion control, and end plates for load distribution. This segmentation allows each component to address specific functions - pain relief through effective load bearing and motion preservation through controlled articulation between segments
Solution Approach 2:
The implant utilizes composite material construction with the inner core made of elastomeric or polymeric material for cushioning, the outer core made of wear-resistant material for motion control, and end plates made of biomaterial for osseointegration. This composite approach enables simultaneous achievement of pain relief through effective load distribution and motion preservation through material-specific properties
2Ease of operation
If total disc replacement is used to preserve motion, then range of motion is maintained, but wear and corrosion from metal-to-metal sliding occur
Solution Approach 1:
The inner core acts as an intermediary element between the end plates, providing a non-metallic bearing surface that eliminates direct metal-to-metal contact. This elastomeric or polymeric inner core absorbs compressive loads and prevents wear and corrosion while allowing controlled motion between the metal end plates
Solution Approach 2:
The implant changes the material parameters of the disc replacement from traditional metal-to-metal interfaces to a composite interface involving elastomeric or polymeric materials. This parameter change in material composition and mechanical properties eliminates wear and corrosion while maintaining motion preservation capabilities
3Ease of operation
If traditional disc replacement is used, then motion is preserved, but shock absorption and cushioning are insufficient
Solution Approach 1:
The inner core is designed as a pre-compression cushioning element made of elastomeric or polymeric material that is positioned between the end plates before implantation. This inner core provides immediate shock absorption and cushioning capabilities, protecting the implant and surrounding structures from impact loads while maintaining motion preservation
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 solution effectively reduces degeneration due to metal wear, increases shock absorption, and maintains spinal motion range, providing a durable and functional alternative to traditional spinal fusion treatments.
Implementation Method 1
an inner core constructed of a polymeric or elastomeric material having varying hardness and other physical properties such as silicone or liquid silicon rubber that provides shock absorption
Implementation Method 2
The outer core is connected between the first end plate and the second end plate through a plurality of interlocking members
Data Source
AI summary
A motion preserving spinal implant is presented for use in placement between intervertebral space for total replacement of a degenerated spinal disc The motion preserving spinal implant has a pair of end plates sandwiched around an inner core and an outer core, with the inner core being concentrically positioned within the outer core. The outer core encapsulates the inner core and provides adequate sealing of the inner core while maintaining flexibility and elasticity to advantageously support physiological movements. The inner core is constructed of an elastomeric material and acts as a solid diaphragm in order to resist and withstand localized compression and other forces. The end plates provide anchoring and fusion with adjoining vertebra and hold the inner and outer cores in place. The motion preserving spinal implant restores the normal height and natural function of the degenerated spinal disc and preserves the natural motion of the spine.