Thirty-three randomised controlled trials with a total of 3,758 participants were included.
Study validity: Only 1/33 studies fulfilled all of the quality criteria (ie a score of 5/5), and a further six studies scored 4/5 points. The randomisation procedure and blinding of the study participants were the two main criteria which studies failed to meet. The statistical power of the studies with negative results was rated as sufficient for only 15% of the studies.
NSAIDs in acute pain (4 studies): There was no evidence for or against the efficacy of NSAIDs for patients with acute symptoms.
Bed rest in acute pain (4 studies): The studies compared different periods of bed rest or the avoidance of bed rest with a short period of bed rest. There was moderate evidence for the efficacy of avoiding bed rest or for short periods of bed rest, in terms of the duration of sick leave after 3 months for patients with and without radiating pain.
Spinal manipulation in acute pain (6 studies): There was limited evidence for the efficacy of spinal manipulation in comparison with placebo in cases of pelvic joint dysfunction. There was moderate evidence that spinal manipulation was more effective in the short run than other conservative types of treatment like physiotherapy, at least for patients without radiating pain.
Back schools or exercise therapy in acute pain (7 studies): There was no evidence for the efficacy of back schools or exercise therapy, or that they were more effective than usual care.
Case management methods (4 studies): There was no evidence for the efficacy of case management methods or for their efficacy in comparison with conventional treatment.
Antidepressants in chronic pain (1 study): There was limited evidence of efficacy after 2 months of antidepressant therapy.
NSAIDs in chronic pain (1 study): There was no evidence for or against the effectiveness of NSAIDs.
Spinal manipulation in chronic pain (2 studies): There was no evidence for the efficacy of spinal manipulation, whether compared with placebo or other treatments.
Back schools or exercise therapy in chronic pain (5 studies): The results were contradictory and so there was no evidence that back schools or exercise therapy were more effective than usual care.
Behavioural therapy in chronic pain (3 studies): There was no evidence that cognitive-behavioural group therapy as part of progressive-relaxation training is more effective in the long term than progressive-relaxation training alone.
Case management methods in chronic pain: No studies were identified.