Incidence and Associated Factors for Kyphosis Progression in Short-Segment Fixation Thoracolumbar Spine Fractures

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Figure 1
Radiographs of patients who are stable (A, B, and C) and kyphosis progression (D, E, and F) after short-segment pedicle fixations. (A) and (D) were obtained immediately after injuries. (B) and (E) were obtained after fixation. (C) and (F) were obtained at a 2-y follow-up.
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Figure 2
Study flowchart.

Table 1

Demographic data compared between the kyphosis progression and stable groups.

Associated Factors	Kyphosis Progression Group (n = 32)	Stable Group (n = 59)	P Value
Age, y, mean ± SD	43.56 ±15.5	42.92 ±11.5	0.821
>60 y, n (%)	5 (15.6%)	4 (6.8%)	0.269
Gender, n (%)
Male	23 (71.8%)	36 (61.2%)	0.362
Female	9 (28.2%)	23 (38%)
Body mass index, mean ± SD	23.24 (±3.4)	22.63 (±3.3)	0.403
>25, n (%)	9 (28.1%)	14 (23.7%)	0.801
Fracture level, n (%)
T11	0	1 (1.7%)	0.711
T12	6 (18.8%)	16 (27.1%)
L1	16 (50.0%)	29 (49.2%)
L2	10 (31.2%)	13 (22.0%)
AO spine Thoracolumbar injuries system, n (%)
B1/B2	1 (3.0%)	5 (8.5%)	0.326
A2	3 (9.4%)	6 (10.2%)
A3	14 (43.8%)	33 (55.9%)
A4	14 (43.8%)	15 (25.4%)
Posterior ligamentous complex injuries, n (%)	20 (62.5%)	27 (45.8%)	0.187
Thoracolumbar injury classification and severity score, mean ± SD	4.69 ± 0.64	4.62 ± 0.87	0.399
Initial kyphotic angle, mean ± SD	15.41 ± 9.9	15.08 ± 8.3	0.869
Postoperative kyphotic angle, mean ± SD	3.72 ± 8.0	4.36 ± 7.4	0.705
Loss correction angle, mean ± SD	9.47 ± 3.6	2.29 ± 1.7	<0.001
Intermediate screw, n (%)	29 (90.6%)	54 (91.5%)	1.000
Surgical technique, n (%)
Open technique	10 (31.3%)	17 (28.8%)	0.814
Minimally invasive technique	22 (68.7%)	42 (71.2%)
Follow-up time, mean ± SD	21.98 ± 10.3	26.76 ± 9.9	0.031
Load-sharing classification
Comminution
1	9 (28.1%)	18 (30.5%)	0.569
2	12 (37.5%)	27 (45.8%)
3	11 (34.4%)	14 (23.7%)
Apposition
1	11 (34.4%)	23 (39.0%)	0.769
2	14 (43.8%)	27 (45.8%)
3	7 (21.8%)	9 (15.2%)
Reduction
1	3 (9.4%)	6 (10.2%)	0.466
2	8 (25%)	22 (37.3%)
3	21 (65.6%)	31 (52.5%)
Total score >6	17 (53.1%)	22 (37.3%)	0.185

Table 2

Multivariable logistic regression analysis between associated factors and kyphosis progression.

Associated Factors	OR	95% CI	P Value
Age >60 y	3.81	0.66–21.88	0.133
Body mass index >25	1.97	0.63–6.09	0.241
AO spine TL system
B1/B2	1.00
A2	4.45	0.28–70.59	0.290
A3	4.70	0.41–53.29	0.212
A4	7.95	0.69–91.85	0.097
Posterior ligamentous complex injuries	3.14	1.05–9.38	0.040
Intermediate screw	0.11	0.01–0.93	0.043
Minimally invasive technique	0.80	0.27–2.41	0.690

Results were already controlled by the initial and postoperative kyphotic angle and follow-up time.