Table 1 Descriptive summary of patients between the union group and the nonunion group

Age (year)

60.18 ± 6.55

63.72 ± 7.25

0.001

Sex (male/female)

114/187

23/27

0.275

BMI (kg/cm2)

25.93 ± 3.46

25.89 ± 3.22

0.89

Fusion to S1 (yes)

110/301

30/50

0.002

Number of fusion levels

1.78 ± 0.8

2.44 ± 0.81

< 0.001

Mean HU value of L1-4

128.78 ± 40.53

113.73 ± 35.63

0.013

Spondylolisthesis (yes)

96/301

11/50

0.159

Smoking (yes)

43/301

13/50

0.036

Diabetes (yes)

45/301

8/50

0.848