A total of 124 patients was enrolled out of 234 who were eligible: 66 were assigned to the surgical group and 58 to the non-surgical group (). The 4-year follow-up rate was 92% and 86%, respectively. In the surgical group, 88% had undergone surgery at 1 year and 91% at 4 years. In the non-surgical group, 5% had undergone surgery at 1 year and 24% at 4 years.
Exclusion, enrolment, randomisation and follow-up of participants.
In both groups patients had stronger beliefs in surgical compared with non-surgical treatment at baseline (). Crossover patients and withdrawals from surgery were more often men and non-smokers, had higher occupational education and higher comorbidity, but took analgesics less often at baseline. Such patients from the non-surgical group took analgesics more often at baseline.
Healthcare utilisation and return to work
Thirty (49%) and 29 (58%) allocated surgical or non-surgical treatment, respectively, reported visits to a physician for back pain the year before the 4-year follow-up. Physiotherapy (20% vs 22%) and other treatments (16% vs 14%) were taken by a minority in both groups. More patients who had surgery (53% vs 32%) were on disability pension (adjusted OR 2.5; 95% CI 1.1 to 5.9). For the intention-to-treat analysis this difference was no longer significant (p=0.21). The number of patients working full time was not significantly different ( and ).
Crossover, complications and re-operations
Non-adherence was registered in 17 (29%) patients randomly assigned to cognitive intervention and exercises, three (5%) did not have the allocated treatment and 14 (24%) patients later had surgery (). Eleven (17%) patients randomly assigned to surgery were classified as non-adherent, six (9%) did not have lumbar fusion (), two (3%) withdrew and three (5%) patients died. Deaths were not related to the surgical procedures. Four crossover patients operated (25%) in the non-surgical group and 15 (25%) in the surgical group had re-operation.
The reason was persistent complaints or deterioration of the condition. Complications have been described previously.4 5
No major complications occurred in patients operated after the 1-year follow-up.
Main treatment effects
In the intention-to-treat analysis there was no treatment effect for the Oswestry disability index. When adjusted for age, gender, baseline score and previous disc surgery the treatment effect was 1.1; 95% CI –5.9 to 8.2 (). The mean adjusted treatment effect was −1.6; 95% CI −8.9 to 5.6 () according to as-treated analysis. Sensitivity analyses including only those who attended the 4-year follow-up did not alter the results.
The only treatment effect observed in the secondary outcome was a reduction of fear-avoidance beliefs favouring cognitive intervention and exercises ( and ). The mean treatment effect for fear-avoidance beliefs for physical activity was –3.5; 95% CI –5.8 to –1.1 in the intention-to-treat analysis and –2.8; 95% CI –5.3 to –0.4 in the as-treated last analysis, and –4.3; 95% CI –8.3 to –0.2 and –4.8; 95% CI –8.9 to –0.7 for fear-avoidance beliefs for work, respectively. Pain medication was taken daily or weekly by 58% treated with surgery compared with 35% not operated (adjusted OR 2.3; 95% CI 1.0 to 5.2). For the intention-to-treat analysis the difference was no longer significant (p=0.14).