Is transcutaneous electrical nerve stimulation effective in relieving postoperative pain after thoracotomy?

A best evidence topic was constructed according to a structured protocol. The question addressed was whether the use of transcutaneous electrical nerve stimulation (TENS) is effective in reducing post-thoracotomy pain. Of the 74 papers found with a report search, nine prospective randomized controlled trials (RCT), among which three were double-blind, presented the best evidence to answer the clinical question. All investigated the effect of TENS as an adjunct therapy for relieving acute post-thoracotomy pain in patients undergoing thoracic surgery. The authors, journal, date and country of publication, study type, group studied, relevant outcomes and results of these papers are given. We conclude that a vast majority - seven of the nine retrieved studies - were in favor of TENS as an adjuvant to narcotic analgesics for improving outcome after thoracic surgery. Indeed, the interest and benefit has been shown not only in the treatment of acute post-thoracotomy pain (pain scores and narcotic requirements were consistently lower in the TENS group as opposed to the Placebo-TENS group), but also when used together with narcotic analgesics to reduce the duration of recovery room stay and to increase chest physical tolerance (better coughing attempts during chest physiotherapy) with positive effects on pulmonary ventilator function [forced expiratory volume in 1 s (FEV(1)) and/or forced vital capacity (FVC)]. Specifically, the TENS treatment was shown to be ineffective when used alone in severe post-thoracotomy pain (i.e. posterolateral thoracotomy incision), but useful as an adjunct to other medications in moderate post-thoracotomy pain (i.e. muscle sparing thoracotomy incision) and very effective as the sole pain-control treatment in patients experiencing mild post-thoracotomy pain (i.e. video-assisted thoracoscopy incision). Hence, current evidence shows TENS associated with postoperative medications to be safe and effective in alleviating postoperative pain and in improving patient recovery, thus enhancing the choice of available medical care and bettering outcome after thoracic surgery.