Hypoalgesic effect of the transcutaneous electrical nerve stimulation following inguinal herniorrhaphy: a randomized, controlled trial

• Published in: The journal of pain Vol. 9; no. 7; p. 623
• Main Authors: DeSantana, Josimari M, Santana-Filho, Valter J, Guerra, Danilo Ribeiro, Sluka, Kathleen A, Gurgel, Ronaldo Q, da Silva, Jr, Walderi M
• Format: Journal Article
• Language: English
• Published: United States 01-07-2008
• Subjects: Acupuncture Points; Adult; Analgesia, Patient-Controlled - methods; Double-Blind Method; Electric Stimulation Therapy - adverse effects; Electric Stimulation Therapy - methods; Hernia, Inguinal - surgery; Humans; Male; Middle Aged; Pain Measurement - methods; Pain, Postoperative - etiology; Pain, Postoperative - physiopathology; Pain, Postoperative - therapy; Prospective Studies; Transcutaneous Electric Nerve Stimulation - adverse effects; Transcutaneous Electric Nerve Stimulation - methods; Treatment Outcome
• ISSN: 1528-8447
• DOI: 10.1016/j.jpain.2008.01.337

We investigated the effect of transcutaneous electrical nerve stimulation (TENS) for inguinal herniorrhaphy postoperative pain control in a prospective, randomized, double-blinded, placebo-controlled study. Forty patients undergoing unilateral inguinal herniorrhaphy with an epidural anesthetic technique were randomly allocated to receive either active TENS or placebo TENS. Postoperative pain was evaluated using a standard 10-point numeric rating scale (NRS). Analgesic requirements were also recorded. TENS (100 Hz, strong but comfortable sensory intensity) was applied for 30 minutes through 4 electrodes placed around the incision twice, 2 and 4 hours after surgery. Pain was assessed before and after each application of TENS and 8 and 24 hours after surgery. In the group treated with active TENS, pain intensity was significantly lower 2 hours (P = .028), 4 hours (P = .022), 8 hours (P = .006), and 24 hours (P = .001) after the surgery when compared with the group that received placebo TENS. Active TENS also decreased analgesic requirements in the postoperative period when compared with placebo TENS (P = .001). TENS is thus beneficial for postoperative pain relief after inguinal herniorrhaphy; it has no observable side effects, and the pain-reducing effect continued for at least 24 hours. Consequently, the routine use of TENS after inguinal herniorrhaphy is recommended.
This study presents the hypoalgesic effect of high-frequency TENS for postoperative pain after inguinal herniorrhaphy. This may reinforce findings from basic science showing an opioid-like effect provided by TENS, given that high-frequency TENS has been shown to activate delta-opioid receptors.