Expandable Intervertebral Fusion Cage for Minimally Invasive Stabilization
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Solution Overview
Problem
Current spinal fusion devices are not minimally invasive and do not effectively stabilize the spinal segment while creating an optimal space for fusion, addressing the need for improved interbody fusion devices that restore disc height and facilitate bone growth between adjacent vertebrae.
Innovation Solution
An expandable intervertebral fusion cage with upper and lower endplate members and a wedge member, driven by a drive assembly, which translates along a curved central axis to expand and stabilize the intervertebral space without rotation, allowing for height restoration and enhanced bone graft integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If current spinal fusion devices are used, then the procedure can be performed, but the devices are not minimally invasive and do not effectively stabilize the spinal segment
Solution Approach 1:
The fusion cage incorporates an expandable mechanism with a drive member and wedge member that allows the device to transition from a compressed insertion state to an expanded stabilization state. The wedge member translates along a curved central axis to expand the endplate members, providing dynamic adaptation to the intervertebral space while maintaining stability.
Solution Approach 2:
The fusion cage is divided into distinct functional components: upper and lower endplate members for vertebral contact, a wedge member for expansion, and a drive member for actuation. This segmentation allows each component to perform its specific function optimally while enabling minimally invasive insertion followed by reliable expansion for stabilization.
2Length of moving object
If current fusion devices are used, then the procedure can be completed, but they do not restore disc height effectively
Solution Approach 1:
The expansion mechanism utilizes translation of the wedge member along a curved central axis to achieve height restoration in the vertical dimension. This dimensional approach allows effective disc height restoration through a relatively simple translational motion rather than complex multi-axis adjustments.
3Reliability
If current fusion devices are used, then the procedure can be performed, but the risk of device migration is not reduced
Solution Approach 1:
The device is inserted in a compressed state through minimally invasive access, then expanded in situ to achieve stable positioning. The textured bone contacting surfaces on the endplate members are prepared in advance to enhance friction and prevent migration once expanded, combining ease of insertion with long-term stability.
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 expandable fusion cage provides minimally invasive height restoration and stabilizes the spinal segment, facilitating bone fusion and reducing the risk of device migration through textured bone contacting surfaces.
Implementation Method 1
a wedge member having at least one ramp surface, and a drive member that extends along a curved central axis. The wedge member can be supported by the drive member... which causes the ramp surface of the 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
Implementation Method 2
The actuator can be configured to cause the drive member to drive the wedge member to translate in a corresponding expansion direction along the curved central axis without relative rotation between the wedge member and the drive member, which causes the ramp surface of the wedge member to urge at least one of the upper and lower endplate members away from the other
Implementation Method 3
reducing the risk of device migration through textured bone contacting surfaces
Data Source
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.