Sub-Tenon's block: the effect of hyaluronidase on speed of onset and block quality.

Abstract

The role of hyaluronidase on the onset time and quality of single quadrant sub-Tenon's block was studied in a prospective, randomized, double-blind controlled manner. One hundred and twenty consecutive patients undergoing cataract surgery under local anaesthesia received a sub-Tenon's block with either of two local anaesthetic solutions. One consisted of 2% plain lignocaine 3 ml with 0.5% plain bupivacaine 2 ml. The other consisted of 2% lignocaine 1 ml containing 150 i.u. per ml of hyaluronidase with 2% plain lignocaine 2 ml and 0.5% plain bupivacaine 2 ml. The development of akinesia and the resulting block quality were assessed. Akinesia scores were lower at all time intervals and were significantly lower (P < 0.05) up to 9 minutes after block in the hyaluronidase group. However, block quality as assessed by the surgeon was not significantly different between the groups. The addition of 150 IU hyaluronidase significantly speeds up the onset of surgical anaesthesia produced by a sub-Tenon's block.