The effect of anterior quadratus lumborum block on morphine consumption in minimally invasive colorectal surgery: a multicentre, double-blind, prospective randomised placebo-controlled trial.

We investigated the efficacy and safety of a bilateral anterior quadratus lumborum block in patients undergoing minimally invasive colorectal surgery. This was a two-centre, double-blind, prospective, randomised, placebo-controlled trial including 150 patients undergoing laparoscopic colorectal surgery (left- or right hemicolectomy, sigmoidectomy) who were enrolled in the institutional abdominal enhanced recovery programme. Before induction of anaesthesia, patients received a bilateral anterior quadratus lumborum block in the left and right lateral decubitus position under ultrasound guidance and were allocated randomly to receive 30 ml of ropivacaine 0.