High and low frequency TENS reduce postoperative pain intensity after laparoscopic tubal ligation: A randomized controlled trial

Abstract

BACKGROUND: Transcutaneous electrical nerve stimulation (TENS) is an effective adjunctive therapy for postoperative pain; however, effects of different frequencies of stimulation have not been systematically investigated. Laparoscopic sterilization (LS) causes significant pain in the early postoperative period and requires substantial postoperative medication. Therefore, we studied the effects of TENS on postoperative pain after LS through placement of Yoon fallopian rings in a prospective, randomized, double-blinded, and placebo-controlled study. METHODS: Sixty-four patients undergoing LS for uterine tube ligation were randomly allocated to receive either active TENS or placebo TENS. Postoperative pain was evaluated using a standard 11-point numeric rating scale and the McGill Pain Questionnaire (MPQ)-pain rating index and number of words chosen. Both high frequency (100 Hz) and low frequency (4 Hz) TENS, at strong, but comfortable sensory intensity, were applied for 20 minutes through 4 electrodes placed around the surgical incision immediately after surgery. Pain was assessed before and after application of TENS when patients were at postanesthesia care unit (PACU). RESULTS: Both high and low frequency TENS significantly decreased postoperative pain intensity when compared with before administration of TENS using the numeric rating scale (P=0.001), pain rating index (P=0.001), and number of words chosen (P=0.001) compared with placebo TENS (P=0.001). TENS in combination with standard pharmacologic analgesic treatment was efficacious for postoperative pain relief after LS. CONCLUSIONS: We recommend regular use of multimodal therapy with TENS and analgesic drugs after LS with placement of Yoon rings. © 2008 by Lippincott Williams & Wilkins.