Table 1: Baseline Characteristics of All Patients Randomised in the Clinical and Patients as Treated in the Present Study. Means ± SD or Number of Patients (%) are Given

Characteristics Lumbar Fusion Cognitive Intervention and Exercises

All Randomised (n = 66) Had Fusion in the Present Study (n = 23) All Randomised (n = 58) Had No Fusion in the Present Study (n = 25)

Age (years) 42.7 ± 8.0 44.0 ± 9.0 42.4 ± 8.0 41.7 ± 8.0

Men 27 (41) 11 (48) 29 (50) 14 (56)

Years from first pain episode 8.9 ± 7.9 9.6 ± 8.1 9.6 ± 7.4 8.3 ± 5.3

Married/living together 57 (86) 20 (87) 49 (81) 21 (84)

Occupational education < 3 years 45 (68) 16 (70) 38 (66) 14 (56)

Work status (%)
    -  working 9 (14) 2 (9) 9 (15) 5 (20)
    -  on sick leave 14 (21) 6 (26) 6 (26) 5 (20)
    -  on rehabilitation 29 (44) 8 (35) 22 (38) 10 (40)
    -  disability pension 10 (15) 5 (22) 10 (17) 5 (20)
    -  others 1 4 (6) 2 (8) 1 (2) 0

Back pain (0-100 = worst possible) 63 ± 15 65 ± 15 65 ±13 60 ± 13

Comorbidity 24 (36) 8 (35) 18 (31) 7 (28)

Taking analgesics daily or weekly 40 (61) 18 (78) 40 (69) 13 (52)

Smoking 36 (55) 11 (48) 30 (52) 12 (48)

Previous surgery for disc herniation 29 (44) 10 (43) 31 (53) 13 (52)

1 Others are students, homemakers, unemployed and patients on retirement pensions.