Annulus Plug and Screw for Disc Repair Containment
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Solution Overview
Problem
In intervertebral disc replacement procedures, the hole created in the annulus fibrosis often remains open, allowing bone graft material and biologic materials to migrate out of the disc space, which hinders proper bone growth and stability.
Innovation Solution
A device comprising a cannulated screw, a plug, and an intervertebral spacer is used to securely close the access hole by threading the screw through the plug and spacer, compressing the bone graft material and preventing migration, while a guide wire and bone tamp facilitate the packing and placement of materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the annulus is closed to seal bone graft material within the disc space, then bone graft migration is prevented, but instrument access to complete the procedure becomes difficult
Solution Approach 1:
The annulus is closed before final packing and instrument work is completed. The plug is inserted and secured with a screw to create a sealed environment, allowing subsequent packing operations to be performed within the contained disc space without risk of material migration.
Solution Approach 2:
The closure system is divided into separate components: a plug that fits into the annular defect and a screw that secures the plug. This segmentation allows the plug to be positioned and secured first, then instruments can work through or around the secured plug to complete packing without compromising the seal.
2Ease of operation
If the annulus hole is left open to allow instrument access, then procedure completion is easier, but bone graft material migrates out of the disc space
Solution Approach 1:
The plug is inserted and secured with a screw before final bone graft packing is completed. This preliminary closure creates a contained environment that prevents migration during the remaining packing operations, while still allowing instruments to access the disc space through or around the plug structure.
3Ease of operation
If bone graft material is packed loosely to allow instrument access, then procedure completion is easier, but bone graft material is not securely held in place
Solution Approach 1:
The plug and screw assembly is installed before final packing to establish containment boundaries. This allows subsequent packing operations to apply sufficient compression force to securely hold bone graft material in place, knowing that the containment structure is already established and will prevent migration during and after packing.
4Device complexity
If biologic material is provided to the disc space without secure containment, then procedure simplicity is maintained, but biologic material migrates to undesired locations
Solution Approach 1:
The plug is inserted and secured with a screw before biologic material is introduced into the disc space. This preliminary containment structure ensures that when biologic material is subsequently provided, it remains confined to the intended disc space location and cannot migrate to undesired areas, while adding minimal complexity to the overall procedure.
Data Source
AI summary
A device for intervertebral disc repair includes a cannulated screw having a head and a shaft, a plug defining an aperture, and an intervertebral spacer. The screw is configured to be placed through the aperture and into engagement with the spacer. A kit includes the device, a guide wire connectable with the spacer, and a bone tamp. Methods of using the device and kit are provided.