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Three Part Question

[In patients with chronic simple low back pain] are [epidural injections better than standard rehabilitation] at [reducing pain and improving function]

Clinical Scenario

A 55 year old woman represents to her general practitioner with back pain of 3 years duration. Previous assessments and investigations have not suggested a serious cause of her back pain but it so severe that she has had to give up work and has become depressed. She attends as she has read on the internet that she can have an epidural to relieve her pain. She asks you if this is true and if so could you refer her for the treatment.

Search Strategy

Cochrane databse of systematic reviews
Medline 1966-June 2005 on OVID via Athens
Medline
[exp INJECTIONS, EPIDURAL/ or exp ANALGESIA, EPIDURAL/] and [low back pain.mp. or exp Low Back Pain/ or exp Back Pain/ or lumbar pain.mp.] limit to [humans and english language and abstracts]
Cochrane: "epidural" and "lumbar"

Search Outcome

Medline: 151 papers of which no randomised controlled trials in simple low back pain were identified. A great number of narrative reviews were identified. No meta-analysis were found.
Cochrane:33 reviews of which one was relevant to the 3 part question.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Nelemans PJ 1999 UNK	Randomised Controlled trials of injection therapy in patients with benign low back pain of more than 1 months duration.	Systematic review.	Authors summary on epidural injections	No conclusion can be made regarding the effect of epidural injection therapy. Four explanatory trials showed non-significant positive results for epidural injections, but the pooled odds ratio was not significantly different from 1. The short-term RR (based on four trials) was 0.93 (0.79-1.09); the long-term RR (based on three trials) was 0.92 (0.76-1.11). These numbers indicate that there is no significant difference between the groups.	A general poor quality and small size of the included trials makes interpretation difficult by the authors. They are therefore only able to draw limited conclusions.
			Trials of short term efficacy of epidural injections explanatory trials	4 trials. All trials reported that pain relief within 6 months after intervention occurred more often in the experimental group, but the differences in proportions of patients with improvement were not statistically significant (alpha=0.05). The pooled RR with 95% confidence interval was: 0.93 (0.79-1.09). As the confidence intervals for the pooled RR cross 1 there is insufficient evidence to recomend this therapy for short term pain relief
			Trials of short term efficacy of epidural injections pragmatic trials	6 trials. 4 showed a non-significant postive effect in the short term.
McLain RF. 1999 USA	Papers on the mechanisms, action and efficacy of epidural steroids in the treatment of back and leg pain	narrative review.	Trials on simple low back pain	No RCTs on simple low back pain. General quality of evidence was poor and limited to patients with radicular pain where there is limited evidence for short term pain relief only.	No data on simple low back pain. Therefore difficult to extrapolate from patients with radicular/sciatic pain.

Comment(s)

Epidural steroids have been advocated for low back pain, predominantly in the management of patients with radicular pain. It is beleived that they may work by reducing the inflammation associated with disc protrusion causing radicular pain. In patients with radicular symptoms this is based upon a rationale pathophysiological argument as disc protrusion/pressure may be a cause of inflammation. There appear to be few trials in patients with simple low back pain and this may reflect the pathophysiological process, as it is difficult to demonstrate inflammatory processes in such patients.

Clinical Bottom Line

There is little evidence, or pathophysiological rationale for the treatment of simple low back pain with epidural steroids.

Level of Evidence

Level 3 - Small numbers of small studies or great heterogeneity or very different population.

References

1. PJ Nelemans, RA de Bie, HCW de Vet, F Sturmans Injection therapy for subacute and chronic benign low-back pain Cochrane database of systematic reviews 1999, Issue 4. Art. No.: CD001824. DOI: 10.1002/14651858.CD001824.
2. McLain RF, Kapural L, Mekhail NA Epidural steroid therapy for back and leg pain: mechanisms of action and efficacy The Spine Journal 2005;5:191-201