D. Carroll et al., RANDOMIZATION IS IMPORTANT IN STUDIES WITH PAIN OUTCOMES - SYSTEMATICREVIEW OF TRANSCUTANEOUS ELECTRICAL NERVE-STIMULATION IN ACUTE POSTOPERATIVE PAIN, British Journal of Anaesthesia, 77(6), 1996, pp. 798-803
We set out to examine the evidence for the importance of randomization
of transcutaneous electrical nerve stimulation (TENS) in acute post-o
perative pain. Controlled studies were sought; randomization and analg
esic and adverse effect outcomes were summarized. Forty-six reports we
re identified by searching strategies. Seventeen reports with 786 pati
ents could be regarded unequivocally as randomized controlled trials (
RCT) in acute postoperative pain. No meta-analysis was possible. In 15
of 17 RCT, we judged there to be no benefit of TENS compared with pla
cebo. Of the 29 excluded trials, 19 had pain outcomes but were not RCT
; in 17 of these 19 TENS studies, the authors concluded that TENS had
a positive analgesic effect. No adverse effects were reported. Non-ran
domized studies overestimated treatment effects.