Vertebral translation at normal levels (data from literature), untreated levels (below or above treated levels), mobile-core implanted levels and fixed-core implanted levels
| Levels | L2-3 | L3-4 | L4-5 | L5-S1 | Difference* between levels |
|---|---|---|---|---|---|
| Normal | −1.07 ± 0.46 n = 59 | −1.22 ± 0.60 n = 58 | −1.03 ± 0.48 n = 49 | +0.03 ± 0.97 n = 37 | |
| Untreated | −1.15 ± 1.12 n = 36 | −1.29 ± 1.02 n = 41 | −1.20 ± 1.28 n = 29 | −1.07 ± 1.61 n = 17 | |
| Mobile-core | −1.10 ± 0.59 n = 21 | −0.79 ± 0.44 n = 35 | ML4L5 versus ML5S1 p = 0.002 | ||
| Fixed-core | −1.74 ± 0.71 n = 15 | −1.61 ± 0.45 n = 18 | FL4L5 versus FL5S1 NS | ||
| Difference* between groups | N versus U NS | N versus U NS | N versus U NS N versus M NS N versus F P < .001 U versus M NS U versus F NS P = .08 M versus F P < .001 | N versus U P = .02 N versus M P < .001 N versus F P < .001 U versus M P < .001 U versus F P < .001 M versus F P < .001 |
Abbreviations: n, number of cases available; N, normal levels; U, untreated levels; M, mobile-core implanted levels; F, fixed-core implanted levels; NS, not significant (P > .05)
↵* The Wilcoxon test was used to compare U and M and F. The Student's test was used to compare N to all the other levels. Vertebral translation is expressed in millimeters for 10° of range of motion. Means ± standard deviation are shown.