Expandable Intervertebral Fusion Cage With Nested Wedge Mechanism
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Solution Overview
Problem
Current spinal fusion devices are inadequate for providing minimally invasive stabilization and optimal space creation for spinal fusion, particularly in managing degenerative disc disease (DDD) by maintaining disc height and facilitating bone growth between vertebrae.
Innovation Solution
An expandable intervertebral fusion cage with upper and lower endplate members and wedge members, driven by a drive assembly, allowing for controlled expansion to restore intervertebral space height and stabilize the spinal segment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional fusion devices are used, then spinal fusion can be achieved, but the procedure requires extensive dissection and large incisions
Solution Approach 1:
The fusion cage is designed with a nested structure where the distal wedge member and proximal wedge member are positioned within the cage body, allowing the entire assembly to be inserted through a minimally invasive approach and then expanded in situ to achieve stable spinal fusion
2Ease of operation
If the fusion cage is inserted in a compressed state, then minimally invasive insertion is achieved, but the device occupies less space needed for optimal fusion
Solution Approach 1:
The fusion cage transitions from a static compressed insertion state to a dynamic expanded functional state through the actuation of wedge members that drive endplate separation, allowing the device to occupy the appropriate volume for optimal fusion after insertion
3Volume of moving object
If the fusion cage expands to restore disc height, then optimal space for fusion is created, but the structural integrity may be compromised
Solution Approach 1:
The fusion cage is segmented into multiple functional components (endplate members, wedge members, drive member, actuator) that work together to achieve controlled expansion while maintaining structural integrity through the coordinated interaction of these segments
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 fusion cage effectively expands to restore disc height, stabilize the spinal segment, and facilitate bone growth between vertebrae, providing a minimally invasive solution for spinal fusion.
Implementation Method 1
an actuator that is configured to cause the drive member to drive the distal wedge member to translate in a corresponding expansion direction along the curved central axis without relative rotation between the distal wedge member and the drive member, which causes the ramp surface of the distal wedge member to urge at least one of the upper and lower endplate members away from the other of the upper and lower endplate members
Data Source
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AI summary
An intervertebral implant includes a first endplate member and a second endplate member, and a distal wedge member and a proximal wedge member that couple the first and second endplate members together. The distal wedge member is configured to move in an expansion direction that causes the fusion cage to move from a contracted position to an expanded position.