title: Transcutaneous electrical nerve stimulation (TENS) can reduce postoperative analgesic consumption. A meta-analysis with assessment of optimal treatment parameters for postoperative pain.
abstract: OBJECTIVE
  We investigated the literature of randomised placebo-controlled trials to find out if transcutaneous electrical nerve stimulation (TENS) or acupuncture-like transcutaneous electrical nerve stimulation (ALTENS) can reduce analgesic consumption after surgery.
  
  
  RESULTS
  Subgroup analysis for adequate treatment (pulse frequency: 1-8Hz [ALTENS] or 25-150Hz [TENS], current intensity: "strong, definite, subnoxious, maximal tolerable" or above 15mA, and electrode placement in the incision area) were performed. Twenty-one randomised, placebo-controlled trials with a total of 1350 patients were identified. For all trials, the mean reduction in analgesic consumption after TENS/ALTENS was 26.5% (range -6 to +51%) better than placebo. Eleven of the trials compromising 964 patients, had reports which stated that a strong, subnoxious electrical stimulation with adequate frequency was administered. They reported a mean weighted reduction in analgesic consumption of 35.5% (range 14-51%) better than placebo. In nine trials without explicit confirmation of sufficient current intensity and adequate frequency, the mean weighted analgesic consumption was 4.1% (range -10 to +29%) in favour of active treatment. The difference in analgesic consumption was significantly (p=0.0002) in favour of adequate stimulation. The median frequencies used in trials with optimal treatment was 85Hz for TENS and 2Hz in the only trial that investigated ALTENS.
  
  
  CONCLUSIONS
  TENS, administered with a strong, subnoxious intensity at an adequate frequency in the wound area, can significantly reduce analgesic consumption for postoperative pain.
authors.affiliation: Section of Physiotherapy Science, University of Bergen, Bergen 5009, Norway. jmb@hib.no
authors.forename: Jan Magnus
authors.initials: JM
authors.lastname: Bjordal
authors.forename: Mark I
authors.initials: MI
authors.lastname: Johnson
authors.forename: Anne Elisabeth
authors.initials: AE
authors.lastname: Ljunggreen
mesh_terms: D000700:Analgesics / Q000008:administration & dosage*; D006801:Humans; D010149:Postoperative Pain / Q000628:therapy*; D004561:Transcutaneous Electric Nerve Stimulation
chemical_list: D000700:Analgesics