Background: Regional anesthesia has been used to reduce acute postsurgical pain and to prevent chronic pain. The best technique, however, remains controversial.
Objectives: The aim of this study was to assess the short- and long-term postoperative analgesic efficacy of ultrasound-guided quadratus lumborum block (QLB) in open gastrointestinal surgery.
Study design: A randomized, double-blinded, controlled trial.
Setting: Operating room; postoperative recovery room and ward.
Methods: One hundred eighteen patients underwent elective gastrointestinal surgery randomly assigned into 2 groups (QLB group or control group). Before anesthetic induction, QLB was performed bilaterally under ultrasound guidance using 20 mL of 0.375% ropivacaine or saline solution at each abdominal wall. The primary outcome was cumulative oxycodone consumption within 24 h after surgery. The secondary outcomes were acute pain intensity, incidence of chronic pain, and incidence of postoperative nausea or vomiting (PONV), dizziness, and pruritus.
Results: The cumulative oxycodone consumption was significantly lower in the QLB group during the first 6, 6-24, 24, and 48 h postoperatively when compared to the control group. At rest or during coughing, the numeric rating scale scores were significantly lower at 1, 3, 6, and 12 h postoperatively in the QLB group compared to the control group. There were no significant differences between the 2 groups regarding the incidence of chronic postoperative pain at 3 or 6 months after surgery. Significant differences were found in the incidence of PONV between the two groups, but other complications, such as dizziness and pruritus, did not differ significantly.
Limitations: We did not confirm the QLB effectiveness with sensory level testing after local anesthetic injection. Cumulative oxycodone consumption could have been affected by the patients' use of oxycodone for nonsurgical pain.
Conclusions: Ultrasound-guided QLB provided superior short-term analgesia and reduced oxycodone consumption and the incidence of PONV after gastrointestinal surgery. However, the incidence of chronic pain was not significantly affected by this anesthetic technique.
Keywords: acute pain; chronic pain; gastrointestinal surgery; ultrasound guidance; Quadratus lumborum block.