A Comparative Study Between Ultrasound-Guided Ilioingunial/Iliohypogastric Nerve Block versus Transverse Abdominis Plane Block in Patients Undergoing Oblique Inguinal Hernia Repair

Abstract Background Poorly controlled acute pain after abdominal surgery is related to somatic pain signals derived from the abdominal wall and is associated with a variety of unwanted post-operative consequences, including patient suffering, distress, respiratory complications, delirium, myocardial ischemia and prolonged hospital stay. Objective Regional anesthesia by (Ultrasound guided (US) Transversus abdominis plane block (TAP) or Ultrasound guided ilioinguinal and iliohypogastric nerves (IIN+IHN) block may be used as components of multimodal anesthesia with a comparable effect. In the present study, Bupivacaine is used to compare between them following inguinal hernia repair. Patients and Methods The study was conducted on 60 randomly chosen patients aged above 18 years, American Society of Anesthesiologists (ASA) class I or II scheduled for elective unilateral open inguinal hernia repair under general anesthesia, in Ain Shams University Hospitals after approval of the medical ethical committee. They were allocated in two groups. TAP block Group: received general anesthesia and (0.2 mL/kg of 0.25% bupivacaine per side), by midaxillary approach, under ultrasound guidance, the probe was placed transversely between the iliac crest and costal margin. Ilioinguinal/ iliohypogastric nerves block group: received general anesthesia, with (0.2 mL/kg of 0.25% bupivacaine per side). The inferior portion of linear ultrasound transducer will be placed over the anterior superior iliac spine with the superior margin of the transducer pointed directly in an oblique plane toward the umbilicus. The superior margin of the ultrasound transducer was slowly rotated superiorly and inferiorly until the fascial plane between the internal oblique and transverse abdominis muscle is identified. Results The results of the study revealed that patients received IIN+IHN block had significantly lower pain scores at 8, 12, 16, 20, and 24 hrs after operation, delayed time for rescue analgesia and decreased total need of analgesic in the first 24hrs post-operative compared to patients who received TAP nerves block. Conclusion IIN+IHN block was effective in reducing postoperative pain scores for 4-6 hours, lowering total 24-h postoperative opioid and analgesic consumption and delaying the need for rescue analgesia after inguinal hernia repair under general anesthesia, compared to TAP nerves block. It will be more useful to study in high-risk hypertensive and cardiac patients and to correlate with plasma catecholamine levels, which reflect the stress response and it is necessary to evaluate postoperative pain on movement in farther studies.