Retrobulbar anesthesia: the role of hyaluronidase

The present study was conducted in 100 patients receiving retrobulbar block for ophthalmic surgery to compare the efficacy of local anesthetic solutions with and without hyaluronidase. All patients received 3.5 ml of a mixture of 3 ml of 0.5% bupivacaine and 2 ml of 2% lidocaine. Seventy-five international units of hyaluronidase were diluted in 5 ml of the local anesthetic mixture and used for 50 of the blocks. The remainder did not receive hyaluronidase. A consistently better motor blockade was achieved with hyaluronidase (P less than 0.001 at 10, 15, and 20 min). This finding has not been conclusively demonstrated before.