Comparison of Ultrasound Guided Hernia Block with Standard Subarachnoid Block: An Open Label Randomised Clinical Study

Introduction: Inguinal hernia surgery is preferably performed under Subarachnoid Block (SAB) or General Anaesthesia (GA). However, some patients may have contraindications for both types of anaesthesia. An Ilioinguinal-Iliohypogastric Nerve (IINIHN) block can be administered for inguinal hernia surgery, but sometimes it provides unsatisfactory anaesthesia, and combining it with the genital branch of the genitofemoral nerve is suggested. The use of ultrasound is recommended to increase efficacy and reduce adverse effects of the block. Aim: To compare the intraoperative anaesthetic efficacy of ultrasound-guided ilioinguinal, iliohypogastric, and genitofemoral nerve blocks, collectively referred to as Hernia Block (HB), with SAB in patients undergoing elective unilateral uncomplicated open indirect inguinal hernia repair. Materials and Methods: An open-label randomised clinical study was designed to include 40 adults aged 18 to 80 years, classified as American Society of Anaesthesiologists (ASA) class I-III, undergoing elective open surgery for indirect inguinal hernia. Patients were randomised into two groups: Group A received SAB, while group B received ultrasound-guided HB only. A comparison was made between both groups in terms of intraoperative anaesthetic efficacy, success rate, duration of analgesia, haemodynamic changes, complications, time to ambulation, patient satisfaction, surgeon satisfaction, and adverse effects. Statistical analysis was performed using Analysis of Variance, Student’s t-test, and the Mann-Whitney test. Results: The median age (range) of group A was 56 (33- 68) years, while that of group B was 50 (26-76) years. Mean arterial pressure showed a statistically significant reduction between 30 to 90 minutes in group A patients (p-value <0.05). The median time taken to perform the block was significantly shorter in group A, at 11 (5-22) minutes, compared to 41 (27- 70) minutes in group B (p-value of 0.002). The median time to onset of surgical anaesthesia was significantly shorter in group A, at 5 (3-10) minutes, compared to 30 (15-75) minutes in group B (p-value=0.003). The duration of analgesia was significantly longer in group B, at 8 (2-11) hours, compared to 5 (3-7) hours in group A (p-value=0.002). The success rate in the ultrasoundguided HB group was 80%, while it was 100% in the SAB group (p-value=0.05). Adverse events related to the procedure were significantly higher in the SAB group (55% vs 10%, p-value=0.003). Both surgeon and patient satisfaction were significantly better in SAB group. The median ambulation time was significantly faster in the ultrasound group, at 5.5 hours, compared to 11.5 hours in the SAB group. Conclusion: The ultrasound-guided HB may be considered an effective alternative with an acceptable success rate to SAB for unilateral indirect inguinal hernia repair, particularly in terms of haemodynamic stability, postoperative analgesia, fewer complications, and early ambulation.