Table 5 Comparison of paraspinal muscle characteristics between the union group and the nonunion group in subgroup analysis according to lumbosacral fusion

Age (year)

60.93 ± 6.96

62.8 ± 6.61

0.208

58.88 ± 5.71

64.33 ± 7.69

< 0.001

Sex (male/female)

79/112

11/9

0.241

35/75

12/18

0.4

BMI (kg/cm2)

25.98 ± 3.51

25.98 ± 3.86

0.998

25.84 ± 3.39

25.82 ± 2.8

0.985

Number of fusion levels

1.63 ± 0.75

2.1 ± 0.72

0.008

2.04 ± 0.83

2.67 ± 0.8

< 0.001

Mean HU value of L1-4

127.09 ± 38.78

120.65 ± 43.8

0.386

131.73 ± 43.42

109.12 ± 28.88

0.018

Smoking (yes)

30

8

0.013

13

5

0.333

MF FI

0.28 ± 0.12

0.29 ± 0.07

0.335

0.26 ± 0.1(0.27 ± 0.1)

0.35 ± 0.12(0.35 ± 0.2)

< 0.001

ES FI

0.21 ± 0.11

0.22 ± 0.07

0.475

0.2 ± 0.1(0.21 ± 0.01)

0.24 ± 0.08(0.23 ± 0.02)

0.021

MF rTCSA

0.5 ± 0.14

0.44 ± 0.1

0.066

0.46 ± 0.12

0.47 ± 0.26

0.399

ES rTCSA

0.75 ± 0.2

0.72 ± 0.22

0.33

0.74 ± 0.19

0.77 ± 0.27

0.984

PS rFCSA

0.59 ± 0.17

0.56 ± 0.17

0.496

0.55 ± 0.15

0.54 ± 0.13

0.98