This systematic review included 30 RCTs with a total of 2,780 patients with LRS that evaluated various conservative treatments. Twelve of the 30 included studies were of high methodological quality and 10 studies were considered clinically relevant. Based on the results of this systematic review regarding the conservative treatment of patients with LRS we conclude that:
- At long-term there is no evidence in favour of corticosteroid injections when compared to placebo, no treatment or NSAID or anaesthetic injection, apart from conflicting evidence for short-term pain relief.
- At short term there is no evidence in favour of traction when compared to sham traction or other conservative treatments.
- At short term there is no evidence in favour of physical therapy compared to inactive treatment, other conservative treatments or surgery.
- At short term there is no evidence in favour of bed rest compared to no treatment.
- At short term there is no evidence in favour of manipulation compared to other conservative treatments or chemonucleolysis.
- At short term there is no evidence in favour of medication compared to placebo.
- No evidence was found regarding acupuncture.
In this review, like every review, there are risks of publication and language bias. There are indications that studies with negative results are not easily published as positive studies [9
]. Furthermore, relevant studies, which are registered in unknown databases may not be included. Because of our extensive search strategy this risk was considered small. Although efforts were made to find all published RCTs in restricted languages (i.e. English, Dutch, French and German), some relevant studies published in other languages might have been missed. Also, the number of non-English journals indexed in searched electronic databases is limited.
There was an overall clinical heterogeneity of the included studies. There appeared to be many differences in study populations i.e. underlying cause of LRS and acute, subacute and chronic patients), interventions, duration of follow-up and outcome measures.
It was considered clinically inappropriate to pool the results of the RCTs in the different types of conservative treatments. Therefore a qualitative analysis was performed, using the five levels of evidence [36
]. Although the levels of evidence used may be considered arbitrary, it seems unlikely that a different rating system would have resulted in different conclusions. But, in this review we included studies that almost all reported no differences in outcomes between intervention and control group. When finding no differences between groups we cannot conclude ‘there is evidence that the intervention is not effective or not different from the control treatment’ [15
]. As recommended by the Cochrane Collaboration than to conclude that there is ‘no evidence for an effect’. The analyses according the five levels of evidence are useful when significant differences are reported between treatment groups. But, when no differences between groups are reported in the majority of the included studies we found it problematic to use the levels, because we cannot conclude for example: ‘there is strong evidence for no evidence of an effect’. Therefore, we have chosen to conclude with statements such as: ‘we found no differences between groups’. The question remains; how many trials are needed or how strong must the evidence be, to conclude that a treatment is not effective.
The methodological quality of the majority of the included studies, although improving over the past several years, was not high. Only 12 of the 30 included studies were regarded of high methodological quality. There is, however, a difficulty in blinding the patients and care provider during most conservative treatments that cannot be compared with placebo (i.e. bed rest, physical therapy, manipulation and traction).
There were studies with small sample sizes available for inclusion in this review. The number of patients in the groups was often too small to reach an adequate statistical power; only 12 studies had groups, that each consisted of over 30 patients, included.
The methodological quality might have been misclassified. Relying on the information in reported RCTs may create bias due to under reporting. But the risk of misclassification is considered small because a valid and reliable criteria list was used [37
The conclusions of this review that included 30 trials are not all in accordance with the conclusions of the review of Vroomen et al. [39
] that included 19 trials. We included more trials that evaluated corticosteroid injections and found no evidence of effect at short or at long-term follow-up. Also regarding traction we found more trials with no evidence of effect at short-term follow-up. Therefore, we do not recommend these two treatment options for patients with LRS. For the other conservative treatment options (physical therapy, bed rest, manipulation and medication) no evidence of effect was found at short-term follow-up, and long-term effects are unknown. At present there is no evidence that one type of treatment is clearly superior to others for patients with a lumbosacral radicular syndrome.