Transcutaneous Electric Nerve Stimulation reduces acute postoperative pain and analgesic use after open inguinal hernia surgery: a randomized, double-blind, placebo-controlled trial.
In this randomized, double-blind, placebo-controlled trial, we evaluated the role of transcutaneous electrical nerve stimulation (TENS) in the multimodal treatment (non-opioid analgesics and kinesiotherapy) of postoperative pain following open inguinal hernia repair. In total, 80 males participants with elective primary unilateral hernia Lichtenstein repair were randomly allocated to receive TENS or a placebo-TENS procedure. The TENS group received local and segmental conventional TENS on the first and second postoperative days. In the placebo-TENS group, intensity was set at 0-0.5mA. Change of pain level at rest, when walking, when standing up from bed, pressure algometry parameters and additional analgesic use were the main outcomes. Reduction of VAS pain score and absolute and relative pain relief were observed in the TENS group following the procedures compared to the placebo-TENS group (p<0.001). The pressure pain threshold and maximal tolerable pressure in the hernia side were equal before the TENS procedure in both groups (p=0.84), but after the procedure, these were higher in TENS group (p<0.001). Additional non-opioid analgesics requirements were lower in the TENS group on the first and second postoperative days (p<0.001). TENS is a safe procedure that can reduce postoperative pain and analgesic use after open inguinal hernia repair. The study was registered in the database of clinicaltrials.gov (register number NCT03739060) Perspective This article presents TENS as a safe and effective non-pharmacologic intervention to reduce post-operative pain after open inguinal hernia repair. TENS could be used in daily practice as part of a multimodal postoperative pain treatment, especially for patients suffering from hyperalgesia.