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Acute Pain | Chronic Pain | General

Transcutaneous electrical nerve stimulation (TENS) in chronic pain

Clinical bottom line:

There is a lack of evidence for the effectiveness of TENS at recommended treatment schedules. At lower treatment schedules in which TENS is used only intermittently or for short periods, there is no evidence that TENS provides effective pain relief. Further trials are required.

TENS was originally developed as a way of controlling pain through the 'gate' theory, where it is believed, selective stimulation of certain nerve fibres could block signals carrying pain impulses to the brain.

TENS is widely used, with for example, an estimated 450,000 users annually in Canadian state hospitals alone.

Systematic review

McQuay, H.J.,Moore, R.A. Chapter 25, Transcutaneous electrical nerve stimulation (TENS) in chronic pain. In: An evidence-based resource for pain relief. Oxford. Oxford University Press, 1998

Inclusion criteria were full journal publication of randomised controlled trials; analgesic effect of TENS in chronic pain patients.

Data extraction from trials was not possible. Reviewers judged trials to establish whether the overall conclusion of the report was positive or negative for the analgesic effectiveness of TENS.


Included trials tended to have treatment regimens shorter than four weeks, with stimulation for less than 10 hours per week. This treatment is of shorter duration and stimulation time than recommended treatments.

TENS versus placebo

Twenty-four trials compared TENS with placebo. Ten of 24 trials had a positive outcome.

TENS versus active treatment

Fifteen trials compared TENS with an active treatment. Three of 15 had a positive outcome.

Frequency and mode

Ten trials compared frequency and mode. In Four of five trials conventional high frequency TENS equalled low frequency pulsed TENS.

Note: since original trials were not blinded, these results are likely to be an overestimation of effectiveness.

Figure: 'Doses' of TENS in included trials

Adverse effects

Not reported.

Further reading

Gadsby, J. G.; Flowerdew, M. W. The effectiveness of transcutaneous electrical nerve stimulation (TENS) and acupuncture-like transcutaneous electrical nerve stimulation (ALTENS) in the treatment of patients with chronic low back pain. In: Bombardier, C.; Nachemson, A.; Deyo, R.; de Bie, R.; Bouter, L.; Shekelle, P.; Waddell, G.; Roland, M., (eds.). CMSG Back Module of The Cochrane Database of Systematic Reviews [updated 05 december 1996]. Oxford: The Cochrane Collaboration; 1997(1). 1-35 The Cochrane Library [database on disk and CDROM].

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