Ultrasound-guided erector spinae plane block for open inguinal hernia repair: a randomized controlled trial

BACKGROUND AND OBJECTIVES: Inguinal hernia repair is associated with significant postoperative pain. We assessed the analgesia efficacy of unilateral Erector Spinae Plane block (ESP) performed under ultrasound guidance in patients submitted to open unilateral inguinal hernia repair, comparing ESP to spinal anesthesia administered with or without opioid. METHODS: Forty-five patients with ages ranging from 27 to 83 years were randomly allocated into three groups: control group receiving spinal anesthesia (n = 14), ESP group receiving ESP block combined with spinal anesthesia (n = 16), and spinal morphine group receiving spinal anesthesia with morphine 1 mcg.kg(-1) as adjuvant drug (n = 15). ESP was performed at the T8 level using 0.5% ropivacaine, 20 mL. We assessed the pain intensity in the initial 24 hours after surgery using the Visual Analogue Scale – VAS and rescue opioid requirement. RESULTS: The ESP group showed four times higher consumption of rescue opioids than the spinal morphine group, or 26.7% vs. 6.2%, respectively (RR = 4.01; 95% CI: 0.82 to 19.42; p = 0.048). The spinal morphine group showed higher incidence of adverse effects than the ESP group, 37.5% vs. 6.7%, respectively (p = 0.039). There were no statistically significant differences among groups for the mean values of VAS score at 24 hours after surgery (p = 0.304). CONCLUSION: At the doses used in this study, the ESP block was an ineffective technique for providing postoperative analgesia in unilateral open inguinal hernioplasty and was associated with higher consumption of rescue opioids when compared to spinal anesthesia with or without opioid.