Biomechanical comparison of posterior intermediate screw fixation techniques with hybrid monoaxial and polyaxial pedicle screws in the treatment of thoracolumbar burst fracture: a finite element study

Table 3 The IDPs of the upper and lower adjacent segments (MPa)

Variable	Normal		MMM		PPP		PMM		MPM		MMP		MPP		PMP		PPM
Variable	U	L	U	L	U	L	U	L	U	L	U	L	U	L	U	L	U	L
Flexion	1.4	0.6	2.1	0.7	1.4	0.3	1.9	0.7	1.8	0.7	1.3	0.4	1.3	0.4	1.3	0.4	1.8	0.8
Extension	1.4	0.8	2.3	0.9	1.6	0.5	2.1	0.8	2.2	0.9	1.8	0.7	1.8	0.6	1.8	0.7	2.1	1.2
Axial rotation	0.9	0.6	1.5	0.8	1.2	0.7	1.3	0.7	1.4	0.7	1.3	1.0	1.1	1.0	1.2	1.0	1.1	0.8
Lateral bending	2.0	1.1	2.9	1.5	2.8	1.5	2.3	1.4	2.3	1.5	2.3	1.4	2.3	1.6	2.3	1.6	2.3	1.7

MMM 6 Mps fixated at three levels; PPP 6 Pps fixated at three levels; PMM 2 Pps fixated at upper level, 4 Mps fixated at lower two levels; MPM 4 Mps fixated at upper and lower two levels, 2 Pps fixated at median level; MMP 4 Mps fixated at upper two levels, 2 Pps fixated at lower level; MPP 2 Mps fixated at upper levels, 4 Pps fixated at lower two levels; PMP 2 Mps fixated at median level, 4 Pps fixated at upper and lower levels; PPM 4 Pps fixated at upper two levels, 2 Mps fixated at lower level

ISSN: 1749-799X