Intervertebral Cage Cam-Blade Mechanism for Secure Repositioning
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Solution Overview
Problem
Existing interbody cages for implantation between vertebrae can migrate laterally when bones move, leading to potential complications and requiring repositioning, which can be difficult and dangerous for patients.
Innovation Solution
A cage design with a cam and blade mechanism that allows controlled partial emergence from opposing support faces, enabling easy repositioning and secure anchoring by manual rotation of a shaft, facilitating surgeon's work and ensuring stable fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a cage with a blade mechanism is used for fixation, then the fixation strength is improved, but the device complexity increases
Solution Approach 1:
The cage is divided into functional segments: a body, a cam mechanism, and a blade mechanism. The cam and blade can independently emerge from the interfacial space to perform different functions - the cam for distraction and the blade for anchoring. This segmentation allows each component to be optimized for its specific function while maintaining overall system manageability.
Solution Approach 2:
The cage incorporates dynamic elements that can change position relative to the body. The cam and blade are coupled with a shaft that allows manual rotation, enabling controlled emergence from the interfacial space. This dynamic capability allows the cage to transition from a compact rest position to an active fixation position, providing strength when needed while maintaining simplicity during implantation.
2Ease of manufacture
If the cage structure is simplified for low production cost, then the ease of manufacture is improved, but the reliability during repositioning deteriorates
Solution Approach 1:
The cam acts as an intermediary mechanism between the surgeon's manual input and the blade's emergence. By rotating the shaft, the surgeon controls the cam's movement, which in turn controls the blade's emergence from the interfacial space. This intermediary mechanism provides reliable, controlled repositioning capability while maintaining a relatively simple overall structure that is easy to manufacture.
Solution Approach 2:
The cage design allows the surgeon to perform repositioning operations using simple manual rotation of the shaft, without requiring complex external tools or equipment. The cam and blade mechanism is designed to respond directly to manual input, enabling the surgeon to control the emergence and retraction of these elements through straightforward rotational motion.
3Device complexity
If the cam and blade remain entirely contained in the interfacial space, then the device complexity is reduced, but the ease of operation for repositioning deteriorates
Solution Approach 1:
The cage incorporates dynamic elements that can change position relative to the body. The cam and blade are coupled with a shaft that allows manual rotation, enabling controlled emergence from the interfacial space. This dynamic capability allows the cage to transition from a compact rest position to an active fixation position, providing strength when needed while maintaining simplicity during implantation.
Solution Approach 2:
The cam and blade are pre-positioned within the interfacial space in a controlled manner, allowing them to emerge only when the surgeon intentionally rotates the shaft. This preliminary positioning ensures that the elements are ready for controlled emergence when needed, while remaining contained during the implantation process, thus maintaining both operational ease and controlled complexity.
Data Source
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AI summary
The invention relates to cages suitable for being implanted between two bone portions (OS1, OS2). The cage comprises a body (10) arranged so as to come into contact with the two bone portions; a cam (20) having a shaft (21); a blade (30) having a shaft (31), the cam (20) and the blade (30) being arranged so that they are entirely contained in the space (40); means for controlling the movement of the cam (20) and the blade (30) relative to the body (10) so that the cam (20) is able to partially emerge from the interfacial space via one (11-1) of the two bearing faces while the blade (30) remains contained in said space (40) and so that the blade (30) is able to partially emerge from the space (40) via one (11-1) of the two bearing faces. The invention may be used to facilitate the implantation of an intervertebral cage.