Table 1 Demographic and perioperative data of the study population stratified by lumbar interbody fusion types

Correction levels

501

84

163

254

Mean correction levels

1.4

1.2

1.6

1.4

Age—year (95% CI)

63 ± 12

55.3 ± 14.8

64.4 ± 8.6

65.2 ± 11.4

 < 0.01**

(61.8–64.3)

(51.7–58.8)

(62.7–66.1)

(63.6–66.9)

Female gender—no. (%)

227/348

47/69

68/101

112/178

0.65

(65.2)

(68.1)

(67.3)

(62.9)

BMI—Kg/m²

26.1 ± 3.9

25.7 ± 3.6

26.7 ± 4.3

25.4 ± 3.3

0.01*

(25.7–26.5)

(24.8–26.5)

(26.1–27.4)

(24.7–26)

HLoS—days (95% CI)

7.9 ± 4

8.5 ± 4.5

8 ± 3.8

7.7 ± 3.9

0.38

(7.5–8.3)

(7.4–9.6)

(7.2–8.7)

(7.1–8.3)

OPD—min (95% CI)

362.4 ± 86.3

362.4 ± 103.4

370 ± 85

358.1 ± 79.8

0.54

(353.3–371.5)

(337.6–387.2)

(353.2–386.8)

(346.3–369.9)

EBL—mL (95% CI)

457.3 ± 421.1

548.6 ± 718.6

410.4 ± 233.7

519.4 ± 294.7

0.04*

(412.9–501.7)

(375.9–721.2)

(364.2–456.5)

(475.8–563)

Pre-OP diagnosis—no. (%)

Discogenic pain

15 (4.3)

11 (11.8)

4 (3.1)

0

HIVD

50 (14.4)

7 (7.5)

7 (5.5)

36 (12.8)

Spinal stenosis

203 (58.3)

21 (22.6)

38 (29.9)

144 (51.1)

Spondylolisthesis

223 (64.1)

49 (52.7)

78 (61.4)

96 (34)

Spondylolysis

11 (3.2)

5 (5.4)

0

6 (2.1)

Operation level(s)—no. (%)

1 level

227 (65.2)

55 (79.7)

57 (56.4)

115 (64.6)

2 levels

89 (25.6)

13 (18.8)

26 (25.7)

50 (28.1)

3 levels

32 (9.2)

1 (1.4)

18 (17.8)

13 (7.3)

Index fusion level—no. (%)

L1/L2

3 (0.6)

0

2 (1.2)

1 (0.4)

L2/L3

45 (9)

5 (6)

17 (10.4)

23 (9.1)

L3/L4

112 (22.4)

11 (13.1)

50 (30.7)

51 (20.1)

L4/L5

249 (49.7)

30 (35.7)

88 (54)

131 (51.6)

L5/S1

92 (18.4)

38 (45.2)

6 (3.7)

48 (18.9)

Fusion status—no. (%)

Grade I

27

6

8

13

Grade II

186

30

60

96

Grade III

274

42

87

145

Fusion rate—no. (%) (Grade II and III)

474/501

78/84

155/163

241/254

0.8

(94.6)

(92.9)

(95.1)

(94.9)

Subsidence—no. (%)

63/501

6/84

16/163

41/254

0.04*

(12.6)

(7.1)

(9.8)

(16.1)