Comparison of three concentrations of ropivacaine in posterior quadratus lumborum block: A randomized clinical trial.

Background: A conclusive evidence regarding the optimal concentration and volume of local anesthetic for quadratus lumborum block is lacking.

Methods: In this single-center, prospective, randomized, controlled study, 60 patients scheduled for laparoscopic colorectal surgery were randomly assigned to 3 different combinations of volume and concentration of ropivacaine (3 mg/kg) - Group 0.25%, Group 0.