Efficacy and safety of 0.5% levobupivacaine versus 0.5% bupivacaine for peribulbar anesthesia

Background: This randomized double-blind study examined the use of a new anesthetic agent, levobupivacaine 0.5%, which is the S(-)-enantiomer of a racemic mixture of bupivacaine, for peribulbar anesthesia and compared it with racemic bupivacaine 0.5% alone or in combination with hyaluronidase 10 IU/mL.

Methods: A total of 160 patients undergoing ophthalmic surgery were randomized into four groups (n = 40 each) to receive inferotemporal peribulbar injection of levobupivacaine 0.5% (group L), racemic bupivacaine 0.5% (group B), levobupivacaine + hyaluronidase 10 IU/mL (group LH), or racemic bupivacaine + hyaluronidase 10 IU/mL (group BH) by two anesthetists and two ophthalmologists in a ratio of 25% each. Ocular akinesia and orbicularis oculi function were evaluated using a three-point scale; a value < 5 points was considered as requiring surgery, and movements were re-evaluated the day following surgery to confirm regression of the block.

Results: The time to onset (12 ± 2.6 minutes versus 13 ± 2.8 minutes) and duration of anesthesia (185 ± 33.2 minutes versus 188 ± 35.7 minutes) were similar between groups L and B. Complete akinesia (score 0) was obtained more frequently when hyaluronidase was used in addition to the anesthetic, with occurrences of 72.5% versus 57.5% in group LH versus L, respectively, and 67.5% versus 45% in group BH versus B. Moderate hypotension (<30% of baseline) was observed in four patients (10%) in group L, two (5.0%) in group B, one (2.5%) in group LH, and three (7.5%) in group BH. The time to onset was significantly different between groups L and BH, B and BH, and LH and BH, and the duration of anesthesia differed significantly between groups B and LH, B and BH, and L and LH. The akinesia score differed significantly between groups L and LH and between groups B and LH (P = 0.043 and P = 0.018, respectively), and the number of patients with a score of 0 differed significantly between groups B and LH and between groups B and BH (P = 0.004 and P = 0.017, respectively).

Conclusion: Levobupivacaine is a long-lasting local anesthetic with limited cardiotoxicity and neurotoxicity, and may be considered the landmark for vitreoretinal surgery in elderly patients.