Clinical properties of levobupivacaine or racemic bupivacaine for sciatic nerve block.

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.