5 | Radiographic fusion | The bone in the fusion area is radiographically more denser and more mature than originally achieved in surgery. And no lucency could be detected between the graft bone and cage with vertebral bone. |
4 | Probable radiographic fusion | Bone bridges the entire fusion area with at least the density originally achieved at surgery, There should be no lucency between the donor bone and vertebral bone. |
3 | Radiographic status uncertain | Bone graft is visible in the fusion area at approximately the density originally achieved surgically. A small lucency or gap may be visible involving just a portion of the fusion area with at least half of the graft area showing no lucency between the graft bone and vertebral bone. |
2 | Probable radiographic pseudarthrosis | based on significant resorption of the bone graft, or a major lucency or gap visible in the fusion area (2 mm or more around the entire periphery of the graft or cage). |
1 | Obvious radiographic pseudarthrosis | based on collapse of the construct, loss of disc height, vertebral slip, loose anchoring wings, displacement of the carbon cage, or resorption of the bone graft. |