Expandable Interbody Cage Arms for Vertebral Subsidence
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional interbody cage devices tend to subside into the cancellous bone tissue of the vertebral endplate, leading to loss of disc height and decompression, necessitating reoperation, due to inadequate surface area and force distribution on stronger cortical bone.
Innovation Solution
An expandable interbody cage device with arms that engage the cortical tissue of the vertebral body, increasing the surface area and distributing forces across the stronger cortical bone, while maintaining a slim profile for insertion and expanding post-insertion to secure engagement between vertebrae, and incorporating bone graft material receptacles for enhanced fusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional interbody cage is used, then the device structure is simple and insertion is easy, but the cage subsides into the cancellous bone tissue causing loss of disc height
Solution Approach 1:
The interbody cage transitions from a static structure to a dynamic expandable structure. The cage is inserted in a compressed state and then expanded within the disc space, allowing it to adapt to the anatomical space while distributing load more effectively to prevent subsidence
Solution Approach 2:
The cage is divided into multiple segments or struts that can independently expand or adjust. This segmentation allows the structure to increase its surface area contact with the vertebral bodies while maintaining structural integrity and reducing point-load subsidence
2Reliability
If the cage surface area is increased to distribute forces, then subsidence risk is reduced, but the device width increases making insertion difficult
Solution Approach 1:
The cage structure employs a nested configuration where the expandable elements are contained within a compact outer envelope during insertion. Once positioned, the inner elements expand to increase the effective surface area for force distribution without requiring a larger insertion profile
Solution Approach 2:
The device transitions from a narrow insertion profile to a wider expanded configuration within the disc space. This dynamic size change allows the cage to achieve adequate surface area for force distribution while maintaining ease of insertion through the narrower access path
3Reliability
If the cage is expanded to engage cortical bone, then subsidence is prevented, but the device complexity and insertion difficulty increase
Solution Approach 1:
The cage is pre-configured with expandable elements that are prepared for deployment but remain compact during insertion. The expansion mechanism is activated after the cage is positioned within the disc space, allowing precise engagement with the cortical bone without requiring complex manipulation during the insertion procedure itself
Data Source
AI summary
Various embodiments of an expandable interbody cage device configured to reduce subsidence into an endplate of a vertebral body by including a plurality of arms that engage the cortical tissue of the vertebral body. The plurality of arms increase the surface area and improve distribution of force, especially around stronger parts of the endplate such as the cortical bone at the rim of the endplate. The expandable interbody cage device maintains a low or slim profile while in a “closed” configuration during insertion between vertebrae and is further operable to laterally expand into an “open” configuration that increases the surface area of the expandable interbody cage device after insertion to securely engage the expandable interbody cage device between the vertebra. The expandable interbody cage device further includes one or more ports and/or cavities in which bone graft material can be disposed within.