Facet joints von Mises stress (MPa) by procedure type.
| Spine Segments | Healthy | LAM | LAM + FFX (Unfused) | LAM + FFX (Fused) | LAM + PS (Unfused) | LAM + PS (Fused) |
| L2-L3 | 3.40 | 3.40 | 5.81 | 6.75 | 6.00 | 6.93 |
| L3-L4 | 3.30 | 3.20 | 6.52 | 7.63 | 7.40 | 7.83 |
| L4-L5 | 3.40 | 3.60 | 6.28 | 11.07 | 0.00 | 0.00 |
| L5-S1 | 1.52 | 1.70 | 2.68 | 3.07 | 3.10 | 3.16 |
Abbreviations: LAM, laminectomy; PS, pedicle screw system.