Transcutaneous Electrical Acupoint Stimulation Reduces Postoperative Analgesic Requirement in Patients Undergoing Inguinal Hernia Repair: A Randomized, Placebo-Controlled Study

Abstract

Given the rising rate of opioid-related adverse drug events during postsurgical pain management, a nonpharmacologic therapy that could decrease analgesic medication requirements would be of immense value. We designed a prospective, placebo-and-randomized controlled trial to assess the clinical effect of transcutaneous acupoint electrical stimulation (TEAS) on the postoperative patient-controlled analgesia (PCA) requirement for morphine, as well as side effects and recovery profile after inguinal hernia repair. Seventy-one subjects undergoing inguinal hernia repair with a standardized anesthetic technique were randomly assigned to one of three analgesic treatment regimens: PCA + TEAS (n = 24); PCA + sham-TEAS (no electrical stimulation) (n = 24), and PCA only (n = 23). The postoperative PCA requirement, pain scores, opioid-related side effects, and blood cortisol levels were recorded. TEAS treatment resulted in a twofold decrease in the analgesic requirement and decreased pain level reported by the patients. In addition, a significant reduction of cortisol level was reported in the TEAS group at 24 h postoperatively compared to the sham and control groups. We conclude that TEAS is a safe and effective option for reducing analgesic consumption and postoperative pain following inguinal hernia repair.

Keywords: TEAS; acupuncture; inguinal hernia; patient-controlled analgesia.

Figure 1

Schematic presentation of the study with special regard to the classification of enrolled participants. TEAS—transcutaneous acupoint electrical stimulation; PCA—patient-controlled analgesia.

Figure 2

Distribution of four portable electro-simulators at enrolled participants.

Figure 3

Differences in values of the level of perceived pain between enrolled participants: (a) Total dose of morphine consumed by patients with a different type of intervention and the result of the analysis of variance and multiple comparisons (Tukey’s post hoc tests); (b) Pain sensation assessed on the VAS scale at discharge by patients differing in the type of intervention and the result of the analysis of variance and multiple comparisons (Tukey’s post hoc tests); (c) Expected boundary values of the perceived pain (mean and their 95% confidence intervals) and the assessment of the impact of treatment; p < 0.00001; (d) Expected boundary values of the perceived pain (mean and their 95% confidence intervals) and time after the surgery; p = 0.028. TG—true group; CG—control group; SG—sham group; VAS—visual analog scale; TMD—total morphine dose in milligrams.

Figure 3

Differences in values of the level of perceived pain between enrolled participants: (a) Total dose of morphine consumed by patients with a different type of intervention and the result of the analysis of variance and multiple comparisons (Tukey’s post hoc tests); (b) Pain sensation assessed on the VAS scale at discharge by patients differing in the type of intervention and the result of the analysis of variance and multiple comparisons (Tukey’s post hoc tests); (c) Expected boundary values of the perceived pain (mean and their 95% confidence intervals) and the assessment of the impact of treatment; p < 0.00001; (d) Expected boundary values of the perceived pain (mean and their 95% confidence intervals) and time after the surgery; p = 0.028. TG—true group; CG—control group; SG—sham group; VAS—visual analog scale; TMD—total morphine dose in milligrams.

Figure 4

Correlation diagram between perceived pain and dose of morphine, Pearson’s correlation coefficient, and the regression line equation. VAS—visual analog scale (pain intensity quantified in points); TMD—total morphine (dose in milligrams).

Figure 5

Cortisol levels (ng/mL) at baseline and follow-up in groups differing in the type of intervention and the result of the analysis of variance and multiple comparisons (Kruskal–Wallis ANOVA).