Table 2.
Median principal strains values obtained in all regions of interest of the treated vertebra (L3) both for standing and upper body flexion on OP, VA, and SAIF models.
| Region of interest | Standing | Upper body flexion | Flexion vs. standing | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| OP | VA | SAIF | VA vs. OP | SAIF vs. OP | SAIF vs. VA | OP | VA | SAIF | VA vs. OP | SAIF vs. OP | SAIF vs. VA | OP | VA | SAIF | |||
| Anterior column | Superior EP | Max princ. strains (%) | 0.018 | 0.010 (*) |
0.002 (*, †) |
−44% | −89% | −80% | 0.059 | 0.025 * |
0.008 (*, †) |
−58% | −86% | −68% | 228% | 150% | 300% |
| Min princ. strains (%) | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | ||
| Anterior wall | Max princ. strains (%) | 0.020 | 0.004 (*) |
0.002 (*, †) |
−80% | −90% | −50% | 0.075 | 0.020 (*) |
0.011 (*, †) |
−73% | −86% | −45% | 275% | 400% | 450% | |
| Min princ. strains (%) | −0.036 | −0.013 (*) |
−0.008 (*, †) |
−64% | −78% | −39% | −0.155 | −0.065 (*) |
−0.036 (*, †) |
−58% | −77% | −45% | – | – | – | ||
| Inferior EP | Max princ. strains (%) | 0.016 | 0.009 (*) |
0.003 (*, †) |
−44% | −81% | −67% | 0.053 | 0.025 (*) |
0.010 (*, †) |
−53% | −81% | −60% | 231% | 178% | 233% | |
| Min princ. strains (%) | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | ||
| Medial column | Superior EP | Max princ. strains (%) | 0.027 | 0.023 (*) |
0.015 (*, †) |
−15% | −44% | −35% | 0.035 | 0.028 (*) |
0.020 (*, †) |
−20% | −43% | −29% | 30% | 22% | 33% |
| Min princ. strains (%) | −0.019 | −0.022 | −0.010 (*, †) |
+16 | −48% | −55% | −0.018 | −0.021 | −0.012 (*, †) |
+17% | −33% | −43% | – | – | – | ||
| Posterior wall | Max princ. strains (%) | 0.025 | 0.013 (*) |
0.007 (*, †) |
−48% | −72% | −46% | 0.036 | 0.011 (*) |
0.004 (*, †) |
−69% | −89% | −64% | 44% | −15% | −43% | |
| Min princ. strains (%) | −0.032 | −0.022 (*) |
−0.021 (*) |
−31% | −34% | −5% | −0.046 | −0.018 (*) |
−0.017 (*) |
−61% | −63% | −6% | – | – | – | ||
| Inferior EP | Max princ. strains (%) | 0.024 | 0.020 | 0.022 | −17% | −8% | −4.5% | 0.033 | 0.018 (*) |
0.024 (*) |
−46% | −27% | +33% | 38% | −10% | 9% | |
| Min princ. strains (%) | −0.007 | −0.005 | −0.014 | −29% | +100% | +180% | −0.011 | −0.004 | −0.017 | −64% | −55% | +325% | – | – | – | ||
Percentage differences for VA vs. OP and for SAIF vs. OP and vs. VA are highlighted in bold, whenever differences are significant. To quantify variations in load sharing due to flexion, percentage strain increase compared to standing are also provided.
*,†
Significant differences (p < 0.05) in median values compared to OP and VA models, respectively.
Negligible compressive strain values (with absolute value < 0.001) are not reported and are here indicated with “–.”