Forward displacement in L4-L5 at a 4 Nm load by procedure.a
| Spine Segments | AP Coordinate No Load | AP Coordinate at 4 Nm Load | Load to No Load Distance | Displacement Variation vs Healthy | Displacement Variation vs LAM |
| Healthy | 15.99 | 15.84 | 0.15 | - | - |
| LAM | 15.99 | 15.79 | 0.20 | 33.3% | - |
| LAM + FFX (U) | 15.99 | 15.94 | 0.05 | −66.7% | −75% |
| LAM + FFX (F) | 15.99 | 15.95 | 0.04 | −73.3% | −80% |
| LAM + PS (U) | 15.99 | 15.99 | 0 | −100% | −100% |
| LAM + PS (F) | 15.99 | 15.99 | 0 | −100% | −100% |
Abbreviations: AP, anteroposterior; F, fused; LAM, laminectomy; PS, pedicle screw system; U, unfused.
Note: Significance threshold = 4.4%.
↵a Loads modeled for sagittal extension only.