Height-Adjustable Spinal Fusion Cage with Stabilized End Plates
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Solution Overview
Problem
Existing spinal fusion cages are not adjustable to the specific spacing between vertebral bodies, requiring multiple product groups and increasing inventory and surgical complexity, with previous adjustable designs experiencing instability and separation issues.
Innovation Solution
A spinal fusion cage with adjustable height, featuring movable blocks and vertical guides to stabilize end plates, allowing linear adjustment to fit varying vertebral spacings and reduce the need for multiple product variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple product groups with different fixed heights are manufactured to fit different vertebral spacings, then the cage can be precisely fitted to various vertebral bodies, but the inventory complexity and surgical complexity increase
Solution Approach 1:
The cage incorporates movable blocks that can shift position along the longitudinal axis, allowing the height of the cage to be dynamically adjusted. This dynamic structure enables a single cage design to accommodate multiple vertebral spacings, eliminating the need for multiple fixed-height product groups and reducing inventory complexity.
Solution Approach 2:
The cage is divided into multiple blocks (first block, second block, third block) that can move independently relative to each other. This segmentation allows the height of the cage to be adjusted by changing the positions of these blocks, providing versatility for different vertebral spacings while maintaining a single product design.
2Device complexity
If a fixed-height cage is used for all vertebral spacings, then the inventory is simplified, but the cage cannot be precisely fitted to various vertebral bodies
Solution Approach 1:
The cage employs movable blocks that can be positioned at different locations along the longitudinal axis to achieve the desired height. This dynamic adjustment mechanism allows precise fitting to various vertebral bodies while maintaining a single simplified product design, thus achieving both inventory simplicity and fit precision.
Solution Approach 2:
The height parameter of the cage can be changed by adjusting the positions of the movable blocks. This parameter change capability allows the same cage design to adapt to different vertebral spacings, providing precise fit without requiring multiple fixed-height products.
3Adaptability or versatility
If previous adjustable cage designs were used, then the height could be adjusted, but the end plates experienced instability and separation issues
Solution Approach 1:
The cage introduces intermediary structures (vertical guides and engagement features) between the movable blocks and the end plates. These intermediaries stabilize the end plates during height adjustment and prevent separation, maintaining reliability while achieving height adjustability.
Solution Approach 2:
The cage employs controlled dynamic movement of blocks within constrained paths defined by vertical guides. This controlled dynamics ensures that the end plates remain stable during adjustment operations, preventing the instability and separation issues observed in previous adjustable designs.
4Quantity of substance
If a single adjustable cage design is used for all vertebral spacings, then the inventory is reduced, but the cage structure becomes more complex
Solution Approach 1:
The cage is segmented into multiple movable blocks that can be independently positioned. This segmentation enables height adjustment functionality within a single design, reducing the need for multiple product groups while keeping the structural complexity manageable through modular block construction.
Solution Approach 2:
The cage design integrates multiple functions into a single structure: the movable blocks serve both as structural components and as adjustment mechanisms. This multi-functionality allows one cage design to accommodate various vertebral spacings, reducing inventory quantity without proportionally increasing complexity.
Data Source
AI summary
The present invention relates to a spinal fusion cage which is inserted between vertebral bodies in a state where the cage has the lowest height and is height-adjustable in the inserted state, thus making it possible to replace cages having heights in a certain range by a single cage. Therefore, manufacturers can reduce product groups that need to be produced and can also reduce product stock. Further, in contrast to the conventional cages having predetermined heights at regular intervals, the height of the inventive cage can be linearly adjusted according to the distance between the vertebral bodies of a patient, and thus a surgery for the patient can be performed using the cage adjusted to an optimum height according to the patient's condition.