Hinged Intervertebral Cage for Lordotic Angle Adjustment
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Solution Overview
Problem
Existing intervertebral fusion cages are often of fixed height and may not provide adequate height restoration or lordotic correction, and they can be challenging to fill with sufficient bone graft for optimal bone regeneration.
Innovation Solution
An adjustably expandable intervertebral cage with first and second endplates connected at a hinge, allowing for a variable lordotic angle correction from 4° to 32°, and a wedge member to maintain the desired expansion and graft containment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed height intervertebral cage is used, then the device structure is simple, but it cannot provide adequate height restoration or lordotic correction
Solution Approach 1:
The cage incorporates a hinge joint connecting the first and second endplates, enabling dynamic adjustment of the lordotic angle between 0° and 32°. This allows the cage to adapt to different spinal deformity requirements while maintaining a relatively simple overall structure, resolving the contradiction between adaptability and complexity.
Solution Approach 2:
The cage is divided into separate endplates (first endplate and second endplate) connected by a hinge, allowing independent adjustment of each component while maintaining structural integrity. This segmentation enables variable angle configuration without requiring a completely complex redesign of the entire cage structure.
2Quantity of substance
If a fixed volume cage is used, then the manufacturing process is simple, but it cannot provide sufficient bone graft volume for optimal bone regeneration
Solution Approach 1:
The expandable cage design allows the internal volume to be adjusted by changing the lordotic angle through the hinge mechanism. The cage can be manufactured in a compressed state and then expanded intraoperatively to the required volume, providing sufficient bone graft space without requiring complex manufacturing processes for different sizes.
Solution Approach 2:
The cage components are designed to be nested or collapsed into a compact form for implantation, then expanded to the desired configuration. This allows a single manufacturing process to produce a cage that can accommodate varying bone graft volumes by simple angular adjustment rather than requiring multiple specialized manufacturing processes.
3Adaptability or versatility
If an expandable cage with variable angle is used, then lordotic correction is improved, but the device complexity increases
Solution Approach 1:
A single hinge joint provides dynamic adjustability between 0° and 32° lordotic angles, achieving variable angle configuration without requiring multiple complex mechanisms. This simple dynamic element enables significant adaptability while minimizing the increase in overall device complexity.
Data Source
AI summary
A fusion cage may include an upper endplate directly hinged to a lower endplate. The fusion cage may be adjustable to provide various angles between the endplates. An insert may be coupled between the endplates to lock the endplates at a selected angle. Fasteners may extend through the fusion cage into adjacent bone portions. An instrument may couple to an endplate so that the hinged-together endplates may be inserted between bone portions. The instrument may be used to adjust the angle between the endplates and to couple the insert between the endplates.