Analgesic efficacy of two approaches of ultrasound-guided quadratus lumborum block for laparoscopic renal surgery: A randomised controlled trial

BACKGROUND: Moderate-to-severe pain exists in the early postoperative period after laparoscopic renal surgery. OBJECTIVE: We investigated the analgesic effect of quadratus lumborum block (QLB) via two approaches in patients undergoing laparoscopic renal nephrectomy. DESIGN: A randomised controlled trial. SETTING: An academic tertiary care hospital in Beijing, China. PARTICIPANTS: Ninety-six patients aged 18 to 70 years who were scheduled for elective laparoscopic radical or partial nephrectomy. INTERVENTIONS: Eligible patients were allocated randomly to a control group (no block), lateral QLB group or posterior QLB group. Ultrasound-guided QLB was performed via either the lateral or posterior approach with 30 ml of 0.4% ropivacaine before surgery. MAIN OUTCOME MEASURES: The primary outcome was sufentanil equivalent consumption within 24 h. Among secondary outcomes, somatic and visceral pain intensity at rest and on coughing were assessed with a numerical rating scale (where 0 = no pain and 10 = the worst pain) until 24 h postoperatively. RESULTS: Sufentanil equivalent consumption did not differ among the three groups (118 ± 36 μg in the control group, 115 ± 47 μg in the lateral QLB group and 119 ± 40 μg in the posterior QLB group; P = 0.955). However, both somatic (lateral QLB vs. control, median difference −1, P < 0.001 at rest and −2 to −1, P < 0.001 on coughing; posterior QLB vs. control, −1, P < 0.001 at rest and −2 to −1, P < 0.001 on coughing) and visceral pain scores (lateral QLB vs. control, −1 to 0, P < 0.001 at rest and −1, P < 0.001 on coughing; posterior QLB vs. control, −1 to 0, P < 0.001 at rest and −2 to −1, P < 0.001 on coughing) were significantly lower in the two QLB groups than in the control group. CONCLUSION: For patients undergoing laparoscopic renal surgery, a pre-operative single-shot QLB via the lateral or posterior approach did not decrease opioid consumption, but improved analgesia for up to 24 h after surgery. TRIAL REGISTRATION: www.chictr.org.cn identifier: ChiCTR1800019883.