Fusion Cage Removable Shield Prevents Bone Graft Leakage
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Solution Overview
Problem
Existing intervertebral fusion cages struggle to retain fusion-promoting material (FPM) inside the cage during implantation, leading to unintended bone growth at inappropriate locations and complications such as heterotopic bone formation and nerve compression.
Innovation Solution
A surgically implantable intervertebral fusion cage equipped with a removable shield or shim that securely holds FPM inside the cage during implantation, using guiding structures to prevent material leakage until desired.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fenestrations are present in the fusion cage to allow bone graft material to escape and contact target vertebrae, then bone fusion is promoted, but the fusion-promoting material leaks out during implantation causing heterotopic bone formation and nerve compression
Solution Approach 1:
A removable shield or retainer is placed inside the fusion cage before implantation to preliminarily contain the fusion-promoting material. This preliminary containment prevents material leakage during the implantation process, and the shield is subsequently removed to allow bone fusion to proceed through the fenestrations
Solution Approach 2:
The removable shield acts as an intermediary element between the fusion-promoting material and the external environment during implantation. It temporarily mediates the containment of material, preventing harmful leakage while allowing the material to remain in place for effective bone fusion after shield removal
2Reliability
If the fusion cage is filled with viscous liquid fusion-promoting material, then bone fusion is enhanced, but the material readily moves from the interior chamber during implantation
Solution Approach 1:
The removable shield is installed before implantation to preliminarily secure the fusion-promoting material in the desired position within the cage. This preliminary securing maintains material stability during the implantation process, and the shield is later removed to allow enhanced bone fusion
3Object-generated harmful factors
If a removable shield is added to retain material inside the cage, then material leakage is prevented, but device complexity increases
Solution Approach 1:
The fusion cage system is segmented into separate functional components: the main cage structure with fenestrations for bone fusion, and a separate removable shield for material containment. This segmentation allows each component to perform its specific function independently, preventing material leakage while maintaining the bone fusion capabilities of the original cage design
Solution Approach 2:
The material retention function is extracted as a separate removable shield component rather than being integrated into the cage structure itself. This extraction allows the shield to be added only when material containment is needed, and removed afterward, thereby preventing material leakage without permanently increasing the complexity of the cage structure
Data Source
AI summary
A bone graft delivery system and method for using same to deliver graft material into a surgical site. The system includes an interbody implant having a securing site disposed on a surface of the implant and a holder having an elongated, hollow handle including a distal end. The distal end of the holder is configured to removably engage the securing site of the interbody implant to secure the interbody implant to the distal end of the holder until such time as a user desires to disengage the holder from the interbody implant. The interbody implant may be a cage implant having opposing anterior and posterior surfaces, opposing first and second lateral surfaces, and opposing top and bottom surfaces, wherein the top surface comprises a first aperture and the bottom surface comprises a second aperture, the posterior surface comprising a third aperture, the first, second, and third apertures all linking to a main cavity, the main cavity generally extending between the top surface and the bottom surface.