Background:
The quadratus lumborum block (QLB) and erector spinae (ESP) block are relatively new, regional analgesic techniques adapted to abdominal surgery to reduce opioid consumption in the postoperative period. The aim of this study was to compare the effectiveness of the ultrasound-guided bilateral ESP block and the bilateral QLB for patients undergoing laparoscopic radical prostatectomy (LRP).

Methods:
Adult patients who underwent LRP were randomly allocated to one of two equal groups. Group I received an ultrasound-guided ESP block with 30 mL of 0.35% ropivacaine on both right and left sides. Group II received an ultrasound-guided QLB1 with 30 mL of 0.35% ropivacaine on both right and left sides.

Results:
There were 104 included patients, 52 patients in the ESP block group and 52 in the QLB group. There was no statistically significant difference in oxycodone consumption within the first 24 hours after surgery between the groups (P = 0.115, 95% CI, for ESP group 17.32–27.56, and for QLB group 22.04–31.07). Pain was evaluated using Numeric Rating Scale (NRS) at 1, 2, 6, 12, and 24 hours after surgery, with no significant differences between the groups (P = 0.325).

Conclusions:
Both bilateral QLB and ESP block provided effective postoperative analgesia in patients undergoing LRP. No statistically significant differences were observed between groups in terms of opioid consumption and pain scores during the first 24 hours. However, this trial was not designed or powered to establish equivalence or non-inferiority, and therefore such conclusions cannot be drawn.