S2-alar-iliac screw and S1 pedicle screw fixation for the treatment of non-osteoporotic sacral fractures: a finite element study

Table 3 Change in relative displacement of the five fixation methods

Motion	Fixation method	The change in relative displacement (mm)
Motion	Fixation method	1	2	3	4
Flexion—standing	LPF	0.3670	0.3455	0.3373	0.3909
	TIFI	0.2906	0.1348	0.0855	0.0630
	SIS	0.0811	0.0291	0.0290	0.0722
	S2AI-S1	0.0492	0.0125	0.0245	0.0581
	S2AI-CS1	0.1308	0.0101	0.0423	0.0878
Right bending—standing	LPF	0.1181	0.0693	0.0526	0.0761
	TIFI	0.1583	0.1147	0.0981	0.1074
	SIS	0.0165	0.0452	0.0624	0.0758
	S2AI-S1	0.0352	0.0101	0.0134	0.0257
	S2AI-CS1	0.0534	0.0015	0.0059	0.0223
Left twisting—standing	LPF	0.1015	0.0915	0.0911	0.1041
	TIFI	0.3292	0.2684	0.2612	0.2001
	SIS	0.0608	0.0659	0.0965	0.0758
	S2AI-S1	0.0255	0.0073	0.0201	0.0123
	S2AI-CS1	0.0418	0.0092	0.0208	0.0139

LPF lumbopelvic fixation, TIFI transiliac internal fixator, SIS sacroiliac screw, S2AI-S1 S2-alar-iliac screw and S1 pedicle screw fixation, S2AI-CS1 S2-alar-iliac screw and contralateral S1 pedicle screw fixation, 1–4, respectively, represent 4 observation points

ISSN: 1749-799X