Articulating Expandable Interbody Fusion Devices for Compact Insertion
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Solution Overview
Problem
Current intervertebral fusion devices face challenges in achieving precise placement on hard cortical bone, maintaining normal anterior column alignment, and minimizing the access window profile to the disc space.
Innovation Solution
The development of an expandable fusion device with first and second lateral legs and link plates that can be pivotably coupled, allowing for a linear orientation for insertion and a widened U-shaped configuration for expanded contact with vertebrae, while incorporating an actuator assembly for height adjustment and strain gauges for force measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the interbody device is inserted through a small access window, then the surgical invasiveness is reduced, but the precise placement on hard cortical bone becomes difficult
Solution Approach 1:
The implant is divided into multiple segments including lateral legs and link plates that can articulate relative to each other. This segmentation allows the implant to be inserted in a collapsed state through a small access window while expanding post-insertion to achieve precise placement and increased contact with cortical bone surfaces.
Solution Approach 2:
The implant transitions from a static, fixed-size device to a dynamic, expandable structure. The lateral legs and link plates can articulate and expand after insertion, allowing the device to adapt its configuration to achieve precise placement on hard cortical bone while maintaining the benefit of a small initial access window.
2Reliability
If the interbody device is expanded to increase contact with cortical bone, then the spinal stability is improved, but the access window profile increases
Solution Approach 1:
The implant utilizes a nested configuration where lateral legs and link plates are collapsed into a compact arrangement that fits through a small access window. After insertion, the structure expands outward to increase contact with cortical bone and improve spinal stability, effectively nesting a large functional device within a small insertion profile.
Solution Approach 2:
The device dynamically changes its dimensions from a compact inserted state to an expanded functional state. This dynamic transformation allows the implant to maintain a small access window profile during insertion while achieving large contact area with cortical bone for enhanced spinal stability after deployment.
3Adaptability or versatility
If the interbody device is made articulating with multiple parts, then the adaptability to spinal alignment is improved, but the device complexity increases
Solution Approach 1:
The implant is segmented into lateral legs and link plates that can articulate relative to each other, providing adaptability to restore normal spinal alignment. This segmentation allows independent adjustment of each component to achieve proper anatomical positioning while maintaining a relatively simple overall structure.
Solution Approach 2:
The articulating components provide dynamic adjustability for restoring spinal alignment without requiring a highly complex mechanism. The lateral legs and link plates can pivot and articulate to accommodate anatomical variations and achieve proper positioning, balancing adaptability with structural simplicity.
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 solution enables precise control of anterior column alignment, increased contact with cortical bone, and reduced access window profile, thereby enhancing spinal stability and fusion outcomes.
Implementation Method 1
an actuator assembly including a rotatable actuator having a shaft and a rotatable nut, and a plurality of driving ramps including a front ramp, a mid-ramp, and a rear ramp positioned along the shaft of the actuator. The upper and lower endplates may be engaged with the plurality of driving ramps. Rotation of the actuator and/or the nut may cause movement of one or more of the driving ramps, thereby causing an expansion in height of the upper and lower endplates.
Data Source
AI summary
Expandable fusion devices, systems, and methods thereof. The expandable implant may include first and second lateral legs and link plates pivotably joined between them. The lateral legs may include upper and lower endplates configured to engage adjacent vertebrae, an actuator assembly including a rotatable actuator having a shaft and a rotatable nut, and driving ramps positioned along the shaft of the actuator. The actuator assembly may cause independent movement of one or more of the driving ramps, thereby causing an expansion in height of the upper and lower endplates of the lateral legs and passive expansion of the connected link plates.