Comparison of Intrathecal Hyperbaric Bupivacaine and Levobupivacaine in Lower Limb Orthopaedic Surgeries: A Prospective Interventional Study

Introduction: Subarachnoid block was widely used for lower limb orthopaedic surgeries. Hyperbaric bupivacaine provides reliable anaesthesia but is associated with higher neurological and cardiac toxicity. Levobupivacaine, the S-enantiomer of bupivacaine, was developed to offer comparable anaesthesia with improved safety and haemodynamic stability. Aim: To compare the effects of intrathecal administration of hyperbaric bupivacaine and levobupivacaine in lower limb orthopaedic surgeries. Materials and Methods: A prospective interventional study was conducted in the Department of Anaesthesiology at Government Medical College, Kozhikode Tertiary Care Hospital, Kerala, India, from January 2023 to December 2023. Total of 120 American Society of Anaesthesiologists-Physical Status (ASAPS) grade I-II patients aged 18-65 years undergoing unilateral lower limb surgeries, who were divided into two equal groups of 60 each based on whichever drug the treating anaesthesiologist selected in routine practice: Group B (hyperbaric bupivacaine 0.5% 2.0 mL+60 mcg buprenorphine) and Group L (hyperbaric levobupivacaine 0.5% 2.0 mL+60 mcg buprenorphine). Motor and sensory block characteristics, duration of effective analgesia and incidence of side-effects were compared. Data were analysed using an Independent samples t-test and a Chisquare test. Results: Both groups L and B were demographically comparable in terms of age, gender, and ASA grading. Group L achieved a significantly faster onset of sensory block (2.99±0.62 vs 4.23±0.83 min, p-value=0.001) and motor block (5.71±1.28 vs 6.43±1.08 min, p-value=0.001). Group B attained a higher sensory level (T6 vs T8, p-value=0.008) and showed longer duration of analgesia (157.3±14.3 vs 150.2±12.3 min; p-value=0.004). Motor regression was faster in group L (198.7±18.8 vs 207.2±14.4 min; p-value=0.006). Incidence of hypotension was significantly higher with bupivacaine (41.7% vs 13.3%; p-value=0.001). Heart Rate (HR) and Mean Arterial Pressure (MAP) trends were comparable between the groups. Conclusion: Compared to intrathecal hyperbaric bupivacaine, hyperbaric levobupivacaine offers faster onset, quicker motor recovery and better haemodynamic stability with reduced hypotension. Bupivacaine provides longer analgesia but at the cost of higher sympathetic blockade. Levobupivacaine was observed to be a safer alternative for lower limb orthopaedic surgeries.