Rotating Interbody Device for Disc Height Restoration
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Solution Overview
Problem
Existing interbody device cages for spinal fusion surgery are limited in their ability to fully restore disc space height, are difficult to place minimally invasively, and can cause nerve injury due to their square or cylindrical shape, which restricts bone graft distribution and fusion surface area.
Innovation Solution
A minimally invasive interbody device assembly with a device that can be inserted in a narrow configuration and rotated to a wide configuration to restore disc space height, allowing bone graft material to be distributed on both sides of the device, which is held in place by surrounding bone and features channels for bone ingrowth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a square or cylindrical cage is used for spinal fusion, then the device can maintain structural stability, but it is difficult to place minimally invasively and can cause nerve injury
Solution Approach 1:
The interbody device transitions from a compressed low-profile configuration during insertion to an expanded configuration after placement. The device includes expansion elements that allow it to dynamically change shape from a narrow insertion profile to a wider stable configuration within the disc space, enabling minimally invasive placement while maintaining structural stability.
Solution Approach 2:
The device utilizes dimensional transformation by compressing in one dimension for insertion and then expanding in that same dimension after placement. This allows the device to pass through narrow access paths and then occupy the full disc space volume, resolving the contradiction between ease of minimally invasive placement and structural stability.
2Reliability
If a traditional cage is used, then the device can provide fusion support, but it cannot fully restore disc space height
Solution Approach 1:
The device dynamically expands after insertion to restore full disc space height. The expansion mechanism allows the device to transition from a compressed insertion state to an expanded operational state that fully restores the disc space, providing both fusion support and height restoration.
Solution Approach 2:
The device is pre-compressed to a smaller size for insertion, then expanded in situ to restore disc space height. This preliminary compression allows the device to be inserted through minimally invasive access while subsequent expansion achieves full height restoration and fusion support.
3Quantity of substance
If a cage is filled with bone graft material before insertion, then the fusion material is in place, but the amount of bone material is limited and distribution is restricted
Solution Approach 1:
The device expands after insertion to create space for bone graft distribution. This dynamic expansion allows bone graft material to be distributed throughout the expanded device volume and into the disc space, increasing both the quantity of bone material that can be used and the distribution effectiveness.
Solution Approach 2:
The device expands in the disc space dimension after insertion, creating additional volume for bone graft material. This dimensional change allows significantly more bone graft to be distributed throughout the disc space compared to pre-filled cages, improving both quantity and distribution.
4Object-affected harmful factors
If a minimally invasive approach is used, then muscle disruption is reduced, but the device is difficult to position accurately
Solution Approach 1:
The device maintains a low-profile compressed configuration during minimally invasive insertion, then expands after placement. This dynamic shape change allows easy passage through narrow access paths while the expansion provides stable positioning and alignment within the disc space, achieving both minimal muscle disruption and accurate positioning.
Data Source
AI summary
A minimally invasive interbody device assembly that includes an interbody device that restores the disc space height between two vertebrae and an instrument detachably coupled to the interbody device for positioning the device in the disc space and delivering bone material to the disc space that is distributed on both sides of the interbody device. The device is inserted into the disc space using the instrument in a direction so that the wide dimension of the device is substantially parallel to the body of the vertebrae. The device is then rotated by the instrument so that the wide dimension of the device becomes perpendicular to the vertebral body so as to cause the disc space height to be restored. Bone graft material is then forced down the instrument so that the bone graft material is distributed on both sides of the device. The instrument is then detached from the device.