Expandable Spinal Fusion Device with Integrated Fixation
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Solution Overview
Problem
Current intervertebral implants tend to migrate after implantation, necessitating supplemental fixation, which complicates the surgical procedure and increases the risk of structural failure due to inadequate initial strength and stability in the intervertebral disc space.
Innovation Solution
A stand-alone expandable interbody spinal fusion device with an integrated fixation mechanism, comprising a superior and inferior component and an expansion mechanism, where a threaded rod or gear system allows for expansion and fixation between vertebral bodies, eliminating the need for supplemental fixation by providing immediate stability and facilitating bony fusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current intervertebral implants are used, then the implant can be placed in the intervertebral disc space, but the implant tends to migrate after implantation due to inadequate initial strength and stability
Solution Approach 1:
The implant incorporates an expandable mechanism that transitions from a compressed delivery state to an expanded deployed state. The expandable cage structure dynamically changes its mechanical properties after implantation, expanding radially to engage the vertebral endplates and provide immediate stability while preventing migration.
Solution Approach 2:
The implant utilizes variable stiffness characteristics through its expandable design. In the compressed state during delivery, the implant has low stiffness for easy insertion. After deployment, it transitions to a high-stiffness expanded state that provides robust fixation and prevents migration, thereby changing the mechanical parameter of stiffness based on the operational phase.
2Stability of the object's composition
If supplemental fixation hardware is added to prevent migration, then implant stability is improved, but the surgical procedure becomes more complex and the risk of structural failure increases
Solution Approach 1:
The implant integrates the fixation function directly into the cage structure through its expandable mechanism. The expansion elements themselves serve as the fixation system, eliminating the need for separate supplemental fixation hardware such as screws or plates. This merging of the support and fixation functions into a single integrated device reduces overall system complexity.
Solution Approach 2:
The expandable cage structure performs multiple functions simultaneously: it provides structural support for the intervertebral space, enables expansion for stable fixation, and prevents migration all through a single device. This multi-functionality eliminates the need for additional specialized fixation components, thereby reducing device complexity.
3Stability of the object's composition
If the implant is made more complex with integrated fixation mechanisms, then migration is prevented, but the device complexity increases
Solution Approach 1:
The expandable mechanism provides a dynamic solution where the implant structure adapts from a compact delivery configuration to an expanded fixation configuration. This dynamic transformation allows the device to achieve stable fixation without requiring permanently complex structures, as the complexity is only present in the transition mechanism rather than in the final deployed state.
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 device provides stable fixation and promotes bony fusion without the need for additional hardware, reducing the risk of migration and complications associated with supplemental fixation, thereby enhancing the success rate of spinal fusion procedures.
Implementation Method 1
an expansion mechanism operatively arranged to displace the superior component relative to the inferior component, the expansion mechanism including a threaded rod including a first end engaged with the superior component and a second end engaged with the inferior component, wherein when the threaded rod is rotated in a first circumferential direction, the superior component is displaced in a first direction relative to the inferior component
Implementation Method 2
the expansion mechanism further comprises a gear rotatably connected to the inferior component, and the second end is fixedly secured to the gear
Implementation Method 3
the expansion mechanism further comprises a worm rotatably connected to the inferior component and engaged with the gear
Data Source
AI summary
A stand-alone expandable interbody spinal fusion device, including a superior component, an inferior component, and an expansion mechanism operatively arranged to displace the superior component relative to the inferior component, the expansion mechanism including a threaded rod including a first end engaged with the superior component and a second end engaged with the inferior component, wherein when the threaded rod is rotated in a first circumferential direction, the superior component is displaced in a first direction relative to the inferior component.