Preemptive Analgesic Effects of Transcutaneous Electrical Nerve Stimulation (TENS) on Postoperative Pain: A Randomized, Double-Blind, Placebo-Controlled Trial.
BACKGROUND
Transcutaneous electrical nerve stimulation (TENS) is a non-pharmacological analgesic method used to control different types of pain.


OBJECTIVE
The aim of this study was to evaluate the effects of preoperative TENS on post inguinal hernia repair pain.


METHODS
This randomized, double-blind, placebo-controlled clinical trial was performed on 66 male patients with unilateral inguinal hernias who were admitted to the Shahid Beheshti hospital in Kashan, Iran, from April to October 2014. Participants were selected using a convenience sampling method and were assigned to intervention (n = 33) and control (n = 33) groups using permuted-block randomization. Patients in the intervention group were treated with TENS 1 hour before surgery, while the placebo was administered to patients in the control group. All of the patients underwent inguinal hernia repair by the Lichtenstein method, and pain intensity was evaluated at 2, 4, 6, and 12 hours after surgery using a visual analogue scale. Additionally, the amounts of analgesic administered by pump were calculated and compared between the two groups.


RESULTS
The mean estimated postoperative pain intensity was 6.21 ± 1.63 in the intervention group and 5.45 ± 1.82 in the control group (P = 0.08). In the intervention group pain intensity at 2 and 4 hours after surgery were 3.54 ± 1.48 and 5.12 ± 1.41 (P < 0.001), respectively. In the control group these values were 4.0±1.5 and 4.76 ± 1.39 (P = 0.04), respectively. No significant differences were observed in mean pain intensities at 6 and 12 hours.


CONCLUSIONS
TENS can reduce postoperative pain in the early hours after inguinal hernia repair surgery.
Department of General Surgery, Kashan University of Medical Sciences, Kashan, IR Iran.
Mohammad
M
Eidy
Trauma Research Center, Kashan University of Medical Sciences, Kashan, IR Iran.
Mohammad Reza
MR
Fazel
Department of General Surgery, Kashan University of Medical Sciences, Kashan, IR Iran.
Monir
M
Janzamini
Trauma Research Center, Kashan University of Medical Sciences, Kashan, IR Iran.
Mostafa
M
Haji Rezaei
Trauma Research Center, Kashan University of Medical Sciences, Kashan, IR Iran.
Ali Reza
AR
Moravveji
Analgesia; Inguinal Hernia; Postoperative Pain; Transcutaneous Electric Nerve Stimulation