Efficacy of quadratus lumborum block using injection bupivacaine as post-operative analgesia in patients undergoing nephrectomy: A randomized double-blind interventional study

Abstract

Background: Nephrectomy is associated with significant post-operative pain, often managed with opioids that carry risks such as respiratory depression and nausea. Quadratus lumborum block (QLB), a regional anesthesia technique, has emerged as a promising alternative for pain relief by targeting both somatic and visceral nerves. However, limited evidence exists on its efficacy in nephrectomy patients, warranting further evaluation.

Aims and Objectives: Nephrectomy is associated with significant post-operative pain, traditionally managed with opioids that pose risks of adverse effects. This study aimed to evaluate the analgesic efficacy and opioid-sparing effects of ultrasound-guided single-shot type 1 QLB using 0.25% bupivacaine.

Materials and Methods: Sixty adult patients undergoing elective nephrectomy were randomized into two groups: Group A received 20 mL 0.25% bupivacaine and Group B received 20 mL 0.9% saline through type 1 QLB under ultrasound guidance. Standardized general anesthesia and post-operative intravenous patient-controlled analgesia with fentanyl were administered. Pain was assessed using the Numeric Rating Scale at multiple intervals up to 24 h. Observer’s Assessment of Alertness/Sedation (OAA/S) scores, opioid requirements, and adverse effects were recorded.

Results: Fifty-eight patients completed the study. Group A showed significantly lower median pain scores at rest, on movement, and during coughing from 1 to 24 h post-extubation (P<0.001 at most time points). Cumulative fentanyl consumption at 24 h was markedly reduced in Group A (155±89 μg vs. 355±53 μg; P<0.001). Higher OAA/S scores were recorded in Group A, with no sedation or motor weakness. No block-related adverse events were noted. Minor complications, such as nausea and ileus, occurred only in Group B.

Conclusion: A single-shot type 1 QLB using 0.25% bupivacaine significantly improves post-operative analgesia, reduces fentanyl consumption, and minimizes opioid-related side effects for 24 h following nephrectomy.