Comparison of the Efficacy of Three Different Opioids as Adjuvants to Hyperbaric Bupivacaine for Subarachnoid Block in Lower Limb Orthopedic Surgeries - A Prospective Randomized and Double Blind Study

Abstract

Background: Regional anaesthesia provides effective intraoperative anaesthesia and postoperative analgesia for orthopaedic procedures. This prospective, randomized, double-blind study compared intrathecal buprenorphine, fentanyl, and nalbuphine as adjuvants to hyperbaric bupivacaine in lower-limb orthopaedic surgeries.

Materials and Methods: After IEC approval and written informed consent, 90 ASA I–II patients undergoing elective lower-limb orthopaedic surgery under combined spinal-epidural anaesthesia were randomized into three groups (n=30 each). All patients received 3 mL of 0.5% hyperbaric bupivacaine with either buprenorphine 150 µg, fentanyl 25 µg, or nalbuphine 1 mg intrathecally. Haemodynamic parameters were monitored throughout surgery and postoperatively. Sensory and motor block characteristics, duration of analgesia, VAS pain scores, sedation, patient satisfaction, and adverse effects were assessed. Appropriate statistical tests were applied.

Results: The three groups were comparable regarding demographic characteristics, sensory block characteristics, onset of motor block, duration of analgesia, haemodynamic parameters, and adverse effects. However, the duration of motor block was significantly longer in the fentanyl group compared with the buprenorphine and nalbuphine groups. Side effects were minimal and comparable among all groups.

Conclusion: Intrathecal fentanyl, nalbuphine, and buprenorphine, when added to hyperbaric bupivacaine, were safe and comparable regarding sensory block, analgesic duration, haemodynamic stability, and adverse effects. Fentanyl significantly prolonged motor block compared with buprenorphine and nalbuphine.