Fig. 5
Longitudinal changes in compression force (a), pullout strength (b), and number of failure and yield elements when 600 N was loaded (c). Longitudinal changes in compressive failure and yield element distribution when 600 N was loaded at the left side of the pedicle screw, and distribution of bone mineral density (d) (**P < 0.05, not significant [n.s.] versus baseline; Friedman’s test). Data are expressed as medians (interquartile ranges)