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

The role of hyaluronidase on the onset rime 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 mi with 0.5% plain bupivacaine 2 ml. The other consisted of 2% lignocaine 1 ml containing 150 IU per ml of hyaluronidase with 2% plain lignocaine 2 mi 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 differ-ent between the groups. The addition of 150 IU hyaluronidase significantly speeds up the onset of surgical anaesthesia produced by a sub-Tenon's block.