Adjustable Intervertebral Fusion Cage with Screw-Driven Height Control
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Solution Overview
Problem
Conventional intervertebral fusion cages have fixed sizes, making it difficult to customize for individual patients, and their square structure can cause instability during insertion and bone graft material filling, especially when the disc space is narrow or curved.
Innovation Solution
An adjustable intervertebral fusion cage with a body, moving member, screw, upper and lower plates, and inclined guides that allow continuous height adjustment and efficient bone graft material space, enabling patient-specific fusion and improved stability during insertion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed-size intervertebral fusion cage is used, then manufacturing and insertion are simple, but it cannot be customized for individual patients and may not fit narrow disc spaces
Solution Approach 1:
The cage incorporates a height adjustment mechanism with movable plates that can be adjusted during surgery to match the patient's specific disc space requirements, transforming a static fixed-size device into a dynamic adjustable one
Solution Approach 2:
The cage is divided into multiple segments including movable plates and adjustment components, allowing independent adjustment of each segment to achieve the desired final height and configuration
2Length of moving object
If height adjustment components are gathered in the center of the interior, then height adjustment is achieved, but the internal space becomes cramped and cannot adequately hold bone graft material
Solution Approach 1:
The height adjustment mechanism operates in the vertical dimension through movable plates that slide along the cage body, while the horizontal internal space remains preserved and unobstructed for bone graft material placement
3Ease of manufacture
If a square symmetrical structure is used, then manufacturing is simple, but it is difficult to push to the frontmost part of the curved intervertebral body and causes instability during fusion
Solution Approach 1:
The cage incorporates an asymmetric inclined surface on its anterior aspect that matches the natural curvature of the intervertebral body, enabling proper positioning and stable engagement while maintaining manufacturing feasibility
4Length of moving object
If the cage height is expanded after implantation, then patient-specific fitting is achieved, but no additional bone graft material can be filled in the expanded space
Solution Approach 1:
The cage design allows height adjustment to be performed before final implantation, enabling the surgeon to pre-adjust the height to match the patient's specific needs and fill the entire cage volume with bone graft material in advance
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 adjustable design allows for precise fitting and stability during fusion, reducing surgical burden and ensuring adequate space for bone graft material, even in narrow or curved spaces.
Implementation Method 1
a screw which is screw-coupled to the body and moves forwards or backwards relative to the body integrally with the moving member when rotating
Implementation Method 2
an upper guide part which is inclined backwards from the front in the upper portion of the body; a lower guide part which is inclined forwards from the rear in the lower portion of the body
Data Source
AI summary
An intervertebral fusion cage is disclosed. An intervertebral fusion cage according to an embodiment of the present invention comprises: a body including a receiving part of which upper and lower portions are open, an upper guide part, and a lower guide part; a moving member disposed in the receiving part; a screw which is screw-coupled to the body and moves forwards or backwards relative to the body integrally with the moving member when rotating; an upper plate which has a guided part guided by the upper guide part and is disposed above the body while being engaged with the moving member; and a lower plate which has a guided part guided by the lower guide part and is disposed under the body while being engaged with the moving member.