Table 6 Comparison of outcomes between patients with a follow-up of < 9 years and ≥ 9 years

NASS⁴

 Pain + disability

 < 9 y

63

2.97

0.67

2.67

0.85

0.46

0.004

 ≥ 9 y

51

3.13

0.79

2.51

0.82

0.79

 < 0.001

 Neurogenic symptoms

 < 9 y

61

2.40

1.14

2.33

1.02

0.06

0.642

 ≥ 9 y

51

2.42

1.05

2.34

1.25

0.08

0.638

Short-Form 36

 Physical functioning

 < 9 y

59

62.98

17.15

61.18

22.38

-0.11

0.476

 ≥ 9 y

40

63.07

16.54

65.81

20.80

0.17

0.418

 Physical role

 < 9 y

59

47.74

39.11

47.88

43.87

0.00

0.646

 ≥ 9 y

40

30.00

35.90

53.13

41.67

0.64

0.005

 Bodily pain

 < 9 y

59

40.53

14.22

51.92

20.81

0.80

 < 0.001

 ≥ 9 y

40

36.38

14.97

56.33

19.86

1.33

 < 0.001

 General health

 < 9 y

59

54.34

16.26

53.03

19.84

-0.08

0.541

 ≥ 9 y

40

51.43

17.91

52.65

17.08

0.07

0.655

 Vitality

 < 9 y

59

48.73

15.13

50.17

19.45

0.10

0.508

 ≥ 9 y

40

50.38

15.75

52.08

15.24

0.11

0.502

 Social functioning

 < 9 y

59

75.21

19.76

71.61

23.99

-0.18

0.265

 ≥ 9 y

40

69.69

24.82

77.81

18.67

0.33

0.042

 Emotional role

 < 9 y

59

83.62

30.56

71.19

43.09

-0.41

0.022

 ≥ 9 y

40

71.67

39.62

78.33

34.22

0.17

0.376

 Mental health

 < 9 y

59

67.93

15.96

68.07

17.71

0.01

0.951

 ≥ 9 y

40

69.73

18.80

72.65

13.44

0.16

0.270

 Physical component summary

 < 9 y

59

36.18

8.13

37.97

10.30

0.22

0.166

 ≥ 9 y

40

33.95

6.81

38.95

9.69

0.73

0.001

 Mental component summary

 < 9 y

59

51.01

8.90

48.86

11.51

-0.24

0.086

 ≥ 9 y

40

50.28

11.02

51.16

8.93

0.08

0.636