Expandable Intervertebral Cage with Segmented Arms for Spinal Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current devices for intervertebral distraction and fusion lack stability during the fusion process, particularly after the distraction device is disconnected, and they do not allow for precise angular orientation of the base plates to match the unique alignment of a patient's spine.
Innovation Solution
An expandable intervertebral cage device with a first and second base plate, a proximal block with internal threading, a distal block with an internal passage, and two arm assemblies, which allows for angular orientation and stable support of the disc space through rotation of a screw, enabling precise distraction and fusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a distraction device is used to separate vertebral bodies, then the disc space is enlarged and nerve root is decompressed, but the device lacks stability after disconnection and does not maintain proper spacing during fusion
Solution Approach 1:
The device transitions from a static cage to a dynamic expandable structure with movable arm assemblies that can be actuated to expand the cage diameter. This allows the device to adapt to the disc space requirements during fusion while maintaining stability through controlled expansion mechanics involving blocks, arms, and fasteners
Solution Approach 2:
The cage is divided into multiple segments including a proximal block, distal block, and intermediate arm assemblies that can move relative to each other. This segmentation allows independent adjustment and expansion of different portions of the device to achieve stable positioning and maintain proper spinal alignment during fusion
2Manufacturing precision
If the disc space is enlarged through distraction, then nerve root decompression is achieved, but precise angular orientation of base plates to match patient's spinal alignment is not possible
Solution Approach 1:
The base plates are made adjustable through the expandable arm mechanism, allowing angular orientation to be modified during implantation to precisely match the patient's unique spinal alignment. The dynamic expansion capability enables real-time adjustment of the base plate angles relative to each other
Solution Approach 2:
The device allows changing of geometric parameters including the angle between base plates and the orientation of arm assemblies. By adjusting the expansion state and arm positioning, the device can be customized to match specific angular requirements of the patient's spinal anatomy
3Reliability
If a traditional cage is implanted, then the procedure is simple, but the device cannot provide stable support and promote vertebral fusion effectively
Solution Approach 1:
The cage incorporates segmented arm assemblies with blocks and fasteners that can be manufactured as separate components and assembled together. This segmentation allows for specialized fabrication of each component with optimized properties for stability and fusion support while maintaining overall device functionality
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 stable support for the disc space during fusion, allows for precise angular orientation of the base plates to match the patient's spinal alignment, and promotes vertebral fusion by maintaining proper spacing and lordosis.
Implementation Method 1
A screw is arranged partially within the internal threading of the proximal block and passing through the internal passage of the distal block, such that rotation of the screw relative to the proximal block causes a change in distance between the proximal block and the distal block, and a corresponding change in the spacing and lordosis of the device.
Data Source
AI summary
An expandable intervertebral cage device includes a first base plate and a second base plate, a proximal block with internal threading that mechanically couples the first base plate and the second base plate, and a distal block comprising an internal passage. The device has exactly two arm assemblies, one on each side. Each arm assembly includes a first arm mechanically coupled to the first base plate and the distal block, and a second arm is mechanically coupled to the second base plate and the distal block. A screw is arranged partially within the internal threading of the proximal block and passes through the internal passage of the distal block, such that rotation of the screw relative to the proximal block causes a change in distance between the proximal block and the distal block, and a corresponding change in the spacing and lordosis of the device.