A clinical trial comparing ultrasound-guided ilioinguinal/iliohypogastric nerve block to transversus abdominis plane block for analgesia following open inguinal hernia repair

Seyed Hamid Reza Faiz,1 Nader D Nader,2 Soraya Niknejadi,1 Sina Davari-Farid,2 Geoffrey G Hobika,2 Poupak Rahimzadeh3 1Department of Anesthesiology, Iran University of Medical Sciences, Tehran, Iran; 2Department of Anesthesiology, University at Buffalo, Buffalo, NY, USA; 3Pain Research Center, Iran University of Medical Sciences, Tehran, Iran Objective: To compare the efficacy of ilioinguinal/iliohypogastric (IINB) nerve block to transversus abdominis plane (TAP) block in controlling incisional pain after open inguinal hernia repair. Patients and methods: This was a prospective randomized clinical trial of 90 patients who received either IINB (N=45) or TAP block (N=45) using 0.2% bupivacaine 15 mL under ultrasound (US) guidance based on a random assignment in the postanesthesia care unit after having an open repair of inguinal hernia. Numeric Rating Scale (NRS) scores were recorded immediately following, 4, 8, 12, and 24 hours after completion of the block. NRS scores at rest and during movement were recorded 24, 36, and 48 hours after surgery. Analgesic satisfaction level was also evaluated by a Likert-based patient questionnaire. Results: NRS scores were lower in the IINB group compared to the TAP block group both at rest and during movement. The difference in dynamic pain scores was statistically significant (P=0.017). In addition, analgesic satisfaction was significantly greater in the IINB group than the TAP block group (mean score 2.43 vs 1.84, P=0.001). Postoperative opioid requirements did not differ between the two groups. Conclusion: This study demonstrated that compared to TAP block, local blockade of ilioinguinal and iliohypogastric nerves provides better pain control after open repair of inguinal hernia when both blocks were administered under US guidance. Greater satisfaction scores also reflected superior analgesia in patients receiving IINB. Keywords: US-guided nerve block, transversus abdominis plane, ilioinguinal, iliohypogastric nerve, inguinal hernia surgery