Clinical properties of levobupivacaine or racemic bupivacaine for sciatic nerve block

Abstract Study Objective: To compare the intraoperative and postoperative clinical properties of the sciatic nerve block performed with either 0.5% bupivacaine or 0.5% levobupivacaine for orthopedic foot procedures. Design: Randomized, double-blind study. Setting: Inpatient unit of a university-affiliated hospital. Patients: 30 ASA physical status I and II patients undergoing elective hallux valgus repair under regional anesthesia. Interventions: After administering intravenous (IV) midazolam premedication (0.05 mg/kg), a femoral nerve block was performed with 15 mL of mepivacaine 2%. Patients were then randomly allocated to receive, in a double-blind fashion, a sciatic nerve block with 20 mL of either 0.5% bupivacaine (n = 15) or 0.5% levobupivacaine (n = 15). Measurements and Main Results: An observer who was blinded to the study drug recorded the onset time, quality, and duration of the sciatic nerve block. Postoperative analgesia consisted of 100 mg IV ketoprofen every 8 hours, with the first administration given at the patient's request. Mean (±SEM) onset time of the sciatic nerve block was 35 ± 5 minutes for bupivacaine and 31 ± 6 minutes for levobupivacaine ( p = not significant [NS]). The duration of motor and sensory blocks with bupivacaine was 761 ± 112 minutes and 790 ± 110 minutes, respectively, and 716 ± 80 minutes and 814 ± 73 minutes, respectively, with levobupivacaine ( p = NS). The first pain medication was requested after 844 ± 96 minutes with bupivacaine and 872 ± 75 minutes after levobupivacaine ( p = NS). No differences in the quality of nerve block and patient satisfaction were reported between the two groups. Conclusions: A dose of 20 mL of 0.5% levobupivacaine induces sciatic nerve block of similar onset, duration, and intensity as the block produced by the same volume and concentration of the racemic solution of bupivacaine.