Post Operative Pain Management for Open Inguinal Hernia Repair under Ultrasound Guidance with two Different Regional Analgesia Techniques: Transversus Abdominis Plane Block VS Ilioinguinal / Iliohypogastric Nerves Block

Introduction. An effective postoperative analgesia is of key importance to facilitate recovery during the immediate postoperative period and to ensure early ambulation. The transversus abdominis plane block (TAP) and ilioinguinal / iliohypogastric nerves block (IHN) are a relatively new regional analgesia techniques that provide a postoperative analgesia in patients undergoing lower abdominal surgery.

Aim of the Study. The objective of this study was to compare the analgesic effectiveness of ultrasound guided TAP block versus ultrasound guided IHN block in the post-operative period of unilateral open inguinal hernia repair.

Materials and methods. One hundred five consented adult patients scheduled for unilateral open inguinal hernia repair were enrolled in this randomised controlled clinical study. US-guided regional analgesia with 0.5 % of levobupivacaine was performed after induction of general anaesthesia (GA). Patients were randomly allocated into two groups: Group A- 53 patients underwent TAP block vs. Group B- 52 patients underwent IHN block. All patients received a standardised GA. Both groups were comparable for age, gender, ASA, and weight. All patients were scheduled for postoperative pain assessment using a visual analogue scale (VAS) at two definite times: 1- VAS1: when patient was awake and conscious post GA; 2- VAS2: when patient requested a rescue analgesia or patient reached 17 hours post block performance.

Results. There were no significant differences in age, gender, ASA, or weight between both groups (p=0.9; p=0.8; p=0.6; p=0.9 respectively).

We found out significant differences comparing VAS score over the time, the IHN block had better effect than the TAP block on relieving pain at the VAS1 (p=0.03) and VAS2 (p=0.04).

The duration of the blocks in group A and group B was as the following:

2-6.5 hrs= [Mean ± SD: 4.2 ± 1.5 vs. 5 ± 0.8 respectively and p=0.03]; 6.5-17 hrs= [Mean ± SD: 11.9 ± 2.3 vs. 14.4 ± 1.7 respectively and p=0.203]; ≥ 17 hrs= [Mean ± SD: 19 ± 1.1 vs. 20.1 ± 2 respectively and p=0.003]. The results of our study were more favourable for the IHN block in all the 3 timing groups.

Conclusions. Ultrasound-guided IHN block provides better pain control and longer duration of action than ultrasound-guided TAP block in the post-operative period of unilateral open inguinal hernia repair.

Both regional analgesia techniques: TAP block and IHN block under ultrasound guidance for open inguinal hernia repair are simple, safe and effective pain control methods.