Bilateral Expansion Intervertebral Fusion Device
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Solution Overview
Problem
Conventional intervertebral body fusion devices often limit expansion to a single direction, restricting orientation and inducing scoliotic angles, and require complex mechanical systems that leave limited space for fusion grafts and complicate surgical implementation.
Innovation Solution
An expandable intervertebral body fusion device with simultaneous bilateral expansion capabilities, featuring flexible arms and slidable wedges that increase device size, allowing for orientation in various directions and reducing foraminal compression, while maintaining a stable motion segment for fusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional single-direction expansion is used, then device orientation is restricted, but device complexity is reduced
Solution Approach 1:
The device is divided into multiple independent expansion mechanisms: a first wedge for uniaxial expansion and a second wedge for bilateral expansion. Each wedge operates independently to expand the cage in different directions, allowing versatile orientation capability while keeping each individual mechanism relatively simple
Solution Approach 2:
The second wedge is positioned within the cage structure and interacts with the branches internally. The nested arrangement of wedges within the cage allows multiple expansion functions to be integrated without proportionally increasing external device complexity
2Adaptability or versatility
If complex mechanical systems are used for expansion, then expansion capability is improved, but space for fusion grafts is reduced
Solution Approach 1:
The expansion mechanisms (wedges and ramps) are extracted as separate, movable components rather than being integrated into the main cage body. This allows the wedges to be positioned in specific locations that minimize encroachment on the internal volume available for fusion grafts while still providing effective expansion capability
Solution Approach 2:
The wedge and ramp system provides dynamic expansion capability where the mechanical components move and adjust during the expansion process. This dynamic mechanism achieves the required expansion function without requiring a permanently complex structural framework that would permanently reduce graft space
3Stability of the object's composition
If flat-shaped cages are used, then bearing angle between vertebrae is improved, but surgical implementation is complicated
Solution Approach 1:
The cage is designed with pre-formed branches and integrated ramp structures that are prepared in advance during manufacturing. These preliminary structural features enable the flat-shaped cage to achieve proper bearing angle stability while allowing for simpler surgical insertion, as the orientation-critical features are already configured before implantation
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 increased stability and flexibility in spinal fusion, allowing for direct lateral approaches and reducing stress on the arms, thereby enhancing clinical utility and surgical options.
Implementation Method 1
A wedge is configured to fit within the cage and move in a lateral direction upon the urging of a spacer-advancing instrument
Implementation Method 2
which flexes the arms and increases the effective size of the device
Data Source
AI summary
An embodiment includes an expandable intervertebral body fusion device with two expansion wedges within a generally hollow main body. After implantation into the intervertebral disc space, the expansion wedges are simultaneously moved from the center of the device toward the ends, which flexes the arms of the cage and increases the size of the implant. This expansion stabilizes the device in the disc space and increases the disc height, thereby reducing foraminal compression of spinal nerves and creating a stable motion segment for eventual fusion. Other embodiments are described herein.