Table 2 L3 lower endplate CSA, fat-free muscle CSA (mean of left and right side), intramuscular fat area (mean of left and right side), and mean normalized fat free muscle CSA of the psoas (PS), lumbar erector spinae (LES) and multifidus (MF) in lumbar discectomy patients with and without pain

Bony CSA

L3 lower endplate

cm²

15,98 ± 2.70

15.30 ± 2.65

Fat-free muscle CSA

L3 lower endplate

Cm²

PS

21.37 ± 6.65

18.71 ± 5.56

LES

34.57 ± 8.36

28.62 ± 6.31

MF

13.25 ± 3.38

10.95 ± 3.44

L4 lower endplate

PS

±

±

LES

25.69 ± 7.16

21.79 ± 5.06

MF

17.22 ± 3.59

14.38 ± 3.97

L5 lower endplate

PS

±

±

LES

14.17 ± 6.31

10,78 ± 5.03

MF

19.49 ± 3.79

15.56 ± 3.32

Normalized fat-free

L3 lower endplate

PS

1.33 ± 0.29

1.21 ± 0.24

muscle CSA

LES

2.21 ± 0.44

1.87 ± 0.34

MF

0.83 ± 0.17

0.71 ± 0.16

L4 lower endplate

PS

±

±

LES

1.64 ± 0.39

1.44 ± 0.32

MF

1.08 ± 0.18

0.94 ± 0.20

L5 lower endplate

PS

±

±

LES

0.90 ± 0.43

0.72 ± 0.30

MF

1.23 ± 0.21

1.02 ± 0.15

Fat area

L3 lower endplate

cm²

PS

0.73 ± 0.45

0.91 ± 0.53

LES

3.26 ± 1.28

4.34 ± 2.13

MF

2.52 ± 1.16

3.52 ± 1.84

L4 lower endplate

PS

±

±

LES

1.21 ± 0.80

1.54 ± 0.87

MF

3.65 ± 1.61

5.08 ± 2.46

L5 lower endplate

PS

±

±

LES

3.56 ± 1.43

5.22 ± 3.05

MF

5.41 ± 1.87

7.19 ± 3.00

Normalized fat CSA

L3 lower endplate

PS

0.05 ± 0.03

0.06 ± 0.03

LES

0.22 ± 0.09

0.29 ± 0.17

MF

0.16 ± 0.09

0.24 ± 0.16

L4 lower endplate

PS

±

±

LES

0.27 ± 0.18

0.33 ± 0.19

MF

0.24 ± 0.12

0.35 ± 0.21

L5 lower endplate

PS

±

±

LES

0.22 ± 0.09

0.37 ± 0.26

MF

0.35 ± 0.14

0.49 ± 0.25