A randomized comparative study of ultrasound-guided quadratus lumborum block versus transversus abdominis plane block in patients undergoing paraumbilical hernia repair

Background
The pain following abdominal surgeries is one of the main problems faced by patients postoperatively and leads to immobility and prolong hospital stay. In the study, we compare the efficacy of two modalities for controlling the pain postoperatively after paraumbilical pain hernia repair.
Aim
To compare the analgesic effect between ultrasound-guided quadratus lumborum block (QLB) and transversus abdominis plane (TAP) block in patients undergoing paraumbilical hernia repair regarding pain control by measuring visual analog scale (VAS) score as the primary outcome. Vital data [systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial blood pressure (MABP), and heart rate (HR)] measured from postanesthetic care unit (PACU) till 24 h postoperatively, the total amount of rescue analgesia, and the time to first analgesia request in the 24 h postoperatively were the secondary outcomes.
Patients and methods
A double-armed prospective randomized comparative study was done in the hospital of Ain Shams University (El-Demerdash Hospital) on 46 patients undergoing paraumbilical hernia repair. The patients were randomly and equally distributed into two main groups. They all received general anesthesia, and after finishing the surgery before extubation, the block was performed under aseptic technique. Group QL (23 patients) received ultrasound-guided bilateral QLB using bupivacaine 0.25% as injection at a volume of 0.2 ml/kg per side, and group TAP (23 patients) received ultrasound-guided bilateral TAP block using bupivacaine 0.25% as injection at a volume of 0.2 ml/kg per side.
Measurements
The primary outcome was the measurement of VAS score, and secondary outcomes were measurement of vital data (SBP, DBP, MABP, and HR) from PACU till 24 h postoperatively at PACU, 30 min in PACU, and then 2, 4, 8, 12, and 24 h postoperatively; the total amount of rescue analgesia; and the time to first analgesia request in the 24 h after operation.
Results
A significant difference was found between the two groups regarding the VAS score, with value less than 0.001, as well as vital data (SBP, DBP, MABP, and HR) measured at PACU, 30 min in PACU, and then 2, 4, 8, 12, and 24 h postoperatively, with value less than 0.001. The total amount of pethidine requested as a rescue analgesia was less in the QL group than the TAP group, with value less than 0.001, and the time to first analgesia request was longer in the QL group than the TAP group, with value less than 0.001.
Conclusion
QLB is more effective for controlling the pain following paraumbilical hernia repair than TAP block and requires less opioids postoperatively as a rescue analgesia.