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Three Part Question

[In patients presenting with sub-acute or chronic low back pain] is [TENS better than placebo] at [reducing pain and discomfort]

Clinical Scenario

A 52 year old man presents to the primary care emergency centre with a 5 month history of back pain. He is dissatisfied with the care given by his usual GP. His GP has performed an X-ray which "Just showed a bit of wear and tear" and he has blood tests (FBC, UE, LFT, ESR, CRP) which have all been normal. He has no neurological signs or "red flag" type symptoms. A diagnosis of musculoskeletal back pain is confirmed. The patient is keen to try one of "those electrical thingies" as his daughter had one during labour and she said it marvellous. You wonder if there is any evidence to support the use of TENS in patients like this.

Search Strategy

Cochrane. Edition 1 2005
MEDLINE 2000-March 2005 on www using OVID interface
Cochrane
Back pain and TENS
MEDLINE
[TENS.mp. or exp Transcutaneous Electric Nerve Stimulation/] AND [back pain.mp. or exp Back Pain/] LIMIT to 2000-2005

Search Outcome

Cochrane
60 citations of which one was directly relevant
30 citations of which one was directly relevant (the same data as on the Cochrane site, with the same authors).

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Brosseau L 2002 Canada	Meta-analysis of studies examining the efficacy of TENS in chronic back pain. Only RCTs included.	Meta-analysis	Search strategy	Wide ranging. Looked for RCTs up to June 2000	Low quality of included studies according to authors criteria. Difficult to achieve true placebos for TENS as patients can detect the effect of electrical stimulation.
			Number of trials included	61 potential studies were identified. 5 trials involving 170 patients met quality criteria for inclusion
			Pain intensity at one month (3 trials)	Standardised mean difference -4.32 in favour of TENS. not statistically significant CI -10.36 to 1.72
			Pain at 6 months (one trial)	Specific data not given. No statistical difference found between treatments.
			Functional status (2 trials)	No difference between groups
			Patient satisfaction (1 trial)	No difference between groups

Comment(s)

A single meta-analysis was found using the search strategies detailed. A further search strategy after 2000 (the last date that the meta-analysis checked to). An examination of the more recent literature reveals many papers comparing different methods of TENS, and or related acupuncture techniques. However, no comparison studies against placebo or sham were found. This meta-analysis suggests that there are no differences beteen active TENS abd placebo. The potential difference found in pain at one month equates to a 4mm difference on a 100mm VAS and is therefore of very low clinical significance. The meta-analyis is well conducted and collates the data well. However, it is limited by the relatively poor quality of the studies. In addition the total number of patients included across all trials, 170, is still modest if we are to demonstratea true effect, or lack of effect.

Clinical Bottom Line

There is no little evidence to advocate TENS for the treatment of chronic low back pain.

Level of Evidence

Level 1 - Recent well-done systematic review was considered or a study of high quality is available.

References

1. Brosseau L, Milne S, Robinson V, Marchand S, Shea B, Wells G, Tugwell P. Efficacy of the transcutaneous electrical nerve stimulation for the treatment of chronic low back pain. Spine (this is the peer reviewed summary of the Cochrane review) 2002;27:596-603