Table 4 Mean (SD) outcome values at 24 months, and differences in changes from baseline to 24 months




Surgery (n=176)

Rehabilitation (n=173)

Difference in change 0-24 months (95% Cl)*

P value{dagger}

Oswestry disability index

(n=138)

(n=146)





    24 months

34.0 (21.1)

36.1 (20.6)

-4.1 (-8.1 to -0.1)

0.045

Shuttle walking test

(n=118)

(n=126)





    24 months

352 (244)

310 (202)

34 (-8 to 77)

0.12

SF-36 physical component score

(n=115)

(n=131)





    24 months

28.8 (14.9)

27.6 (14.6)

2.0 (-1.2 to 5.3)

0.21

SF-36 mental component score









    24 months

47.4 (12.2)

48.1 (12.6)

-0.2 (-2.9 to 2.6)

0.90

Domains of SF-36









General health perception:









    Baseline

47.6 (20.5)

46.5 (22.0)





    24 months

57.7 (23.6)

53.8 (24.5)

3.2 (-1.9 to 8.2)

0.22

Physical functioning:









    Baseline

33.6 (19.0)

39.5 (22.1)





    24 months

50.0 (28.2)

49.8 (28.7)

4.8 (-1.2 to 10.8)

0.11

Role limitation (physical):









    Baseline

15.0 (27.1)

17.6 (30.5)





    24 months

39.6 (42.1)

38.6 (42.7)

2.4 (-7.5 to 12.3)

0.63

Role limitation (emotional):









    Baseline

43.2 (41.4)

51.2 (44.0)





    24 months

65.2 (42.7)

65.4 (43.4)

2.9 (-7.1 to 13.0)

0.57

Pain:









    Baseline

28.6 (17.3)

30.0 (16.0)





    24 months

48.1 (26.4)

44.9 (25.1)

4.1 (-1.67 to 10.0)

0.16

Social functioning:









    Baseline

41.1 (23.3)

42.8 (22.9)





    24 months

53.6 (26.2)

55.6 (26.2)

-0.9 (-6.5 to 4.7)

0.76

Mental health:

60.1 (19.9)

60.3 (21.6)





    Baseline









    24 months

66.5 (21.5)

68.4 (23.1)

-1.8 (-6.4 to 2.8)

0.45

Energy and vitality:

35.4 (20.0)

37.4 (21.7)





    Baseline









    24 months

46.7 (22.8)

46.4 (24.9)

1.5 (-3.8 to 6.7)

0.58

* Adjusted for baseline measures. Rehabilitation group is the reference group.

{dagger} Analysis of covariance adjusted for baseline measure.