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Table 1 Results of the motion parameters

From: Complex biomechanical properties of non-augmented and augmented pedicle screws in human vertebrae with reduced bone density

 Group 1 (non-augmented)Group 2 (augmented)
ParameterScrew headScrew tipScrew headScrew tip
Pdisp0.5 (0.3/1.3)*−0.7 (− 0.6/−1.0)0.3 (0.3/0.4)*− 0.6 (− 0.3/− 0.8)
Pdefl1.4° (1.3°/3.0°)*1.2° (1.1°/1.4°)*
Pstiff216 (76/332)140 (105/162)*295 (285/385)159 (129/297)*
Cdisp1.7 (0.5/2.9)*−1.2 (−0.5/− 1.9)*0.3 (0.2/0.3)*−0.1(− 0.1/− 0.2)*
DEFL7.0° (2.2°/9.6°)**1.9° (1.6°/2.0°)**
STIFF80 (63/316)**122 (83/277)*475 (417/602)**298 (263/340)*
Cmov start0.6 (0.5/0.6)0.9 (0.8/1.2)*0.5 (0.3/0.5)0.7 (0.6/0.9)*
Cmov end0.4 (0.3/0.4)0.7 (0.5/0.8)0.6 (0.3/0.6)0.6 (0.5/0.7)
PDmax0.14 (0.07/0.42)*0.17 (0.11/0.45)*0.02 (0.01/0.02)*0.05 (0.03/0.05)*
  1. Subsidence under preload (Pdisp, n = 12) and its deflection (Pdefl, n = 12) and stiffness (Pstiff, n = 12), subsidence under cyclic loading (Cdisp, n = 10), total deflection (DEFL, n = 10), total stiffness (STIFF, n = 10), screw loosening (Cmov, n = 10), maximum progress of displacement (PDmax, n = 10). Stiffness is in N/mm, and all other values are in mm (Q25/Q75). Significantly different * (p < 0.05), ** (p < 0.01) between group 1 (non-augmented) and group 2 (augmented). The outliers were eliminated from cyclic analysis