Comparison of unilateral and bilateral polymethylmethacrylate-augmented cannulated pedicle screw fixation for the management of lumbar spondylolisthesis with osteoporosis

Table 4 Radiographic characteristics in the 2 groups

Group	UC (n = 29)	BC (n = 21)	P
Intervertebral disk height (mm)
Preoperatively	9.1 ± 3.9	8.9 ± 2.4	0.046
Immediately after surgery*	14.1 ± 2.4	13.5 ± 3.6	0.192
Final follow-up, *	13.5 ± 3.0	12.8 ± 2.5	0.098
Loss of correction	1.4 ± 0.8	1.9 ± 0.9	0.672
Taillard index (%)
Preoperatively	29.8 ± 10.4	30.5 ± 9.1	0.958
Immediately after surgery*	7.4 ± 6.3	6.8 ± 7.8	0.091
Final follow-up, *	7.0 ± 5.9	6.5 ± 7.9	0.193
Loss of correction	0.3 ± 0.4	0.3 ± 0.2	0.289
Screw displacement (mm)
X-p	8.2 ± 4.4	7.4 ± 6.3	0.093
X-f**	8.3 ± 4.7	7.8 ± 4.1	0.321
Y-p	8.5 ± 2.9	8.9 ± 4.7	0.447
Y-f**	8.1 ± 1.8	8.1 ± 5.1	0.632

X distance between the screw tip and the anterior surface of the vertebral body, Y distance from the screw tip to the superior endplate of the vertebral body, -p immediately after surgery, -f final follow-up, UC unilateral PMMA-augmented CPSs, BC bilateral PMMA-augmented CPSs
Values presented are the mean ± SD
Significant if P < 0.05.
*P < 0.05 vs. preoperatively values
**P > 0.05 vs. immediately after surgery values

ISSN: 1749-799X