Expandable Vertebral Body Replacement for Small-Port Insertion
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Solution Overview
Problem
Existing spinal surgeries face challenges in minimizing surgical trauma while ensuring the size of implants can support and promote fusion between vertebrae, as small access ports limit the use of conventional non-expandable interbody devices.
Innovation Solution
An expandable interbody device with inner and outer columns that can be translated vertically via an expansion ring, allowing for expansion to achieve desired lordosis, and includes features like locking arms and an insertion/expansion tool for controlled expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a small access port is created to minimize surgical trauma, then surgical trauma is reduced, but the size of tools and implants that can pass through is limited
Solution Approach 1:
The interbody device is designed to be dynamic rather than static. It is inserted in a collapsed, low-profile state to pass through small access ports, then expanded in situ to achieve the desired large size for spinal support. This dynamic transformation allows the implant to overcome the limitation of small access ports while minimizing surgical trauma.
Solution Approach 2:
The expandable interbody device employs a nested structure where the inner column is contained within the outer column in a collapsed state for insertion. After positioning, the inner column is extended outward from the outer column to achieve the expanded configuration. This nesting allows the large implant to be delivered through a small access port.
2Strength
If non-expandable interbody devices are used, then structural support is provided, but the access port size must be large enough to accommodate the implant
Solution Approach 1:
The interbody device transitions from a static, pre-sized implant to a dynamic, adjustable implant. The expandable structure allows the device to be inserted in a compact form through a small access port, then expanded to provide the necessary structural support for spinal fusion, eliminating the need for a large access port.
Solution Approach 2:
The interbody device is segmented into multiple components including an outer column, an inner column, and an expansion ring. This segmentation allows the device to be collapsed for insertion and then expanded by translating the inner column relative to the outer column, providing structural support without requiring a large access port.
3Area of stationary object
If expandable interbody devices are used, then small access ports can be utilized, but the mechanism for controlled expansion must be reliable
Solution Approach 1:
The expansion mechanism is pre-configured with locking arms that engage with the expansion ring and an insertion tool that is attached before insertion. This preliminary setup ensures that the expansion mechanism is ready for controlled operation immediately after positioning, maintaining reliability while enabling access through small ports.
Solution Approach 2:
The insertion tool serves as an intermediary between the surgeon and the expansion mechanism. It provides controlled force transmission to translate the inner column and expand the device, ensuring reliable and precise expansion without requiring the surgeon to directly manipulate the small components through the limited access port.
Data Source
AI summary
Disclosed herein are expandable interbodies with modular endplates. An expandable interbody has an outer column, an inner column threadedly coupled and translatable relative to the outer column along the longitudinal axis, and an expansion ring to adjust a body length of the expandable interbody. The expansion ring has a plurality of teeth, and the outer column has at least one arm for engaging a tooth of the plurality of teeth to lock the expansion ring. The inner column and/or outer column can include a connector for connection to a modular endplate that has a substantially hollow core. The modular endplate includes a plate with a set screw entrapped therein. The modular endplate has an aperture to receive the connector of the inner and/or outer column.