REGIONAL ANESTHESIA FOR CATARACT-SURGERY - COMPARISON OF 3 TECHNIQUES

Two methods of periocular anaesthesia (PI and PII) were compared with the traditional retrobulbar block in a prospective study of 450 patien ts undergoing elective cataract extraction and intraocular lens implan tation. A solution of local anaesthetic containing equal amounts of 2% lignocaine and 0.5% bupivacaine was used in all the groups. Hyaluroni dase (75 IU/10 ml of local anaesthetic solution) was added. Three grou ps of patients were studied, with 150 patients in each group. The retr obulbar injection (group R) was performed with 4 ml of the anaesthetic solution through the lower eyelid inferotemporally and a further 6 ml was injected for seventh cranial nerve block. In the first periocular technique (group PI) the local anaesthetic was injected inferotempora lly (5 ml) through the lower lid and superonasally (5 ml) through the upper tid. In the second periocular technique (PII) the injections wer e performed inferotemporally (5 ml) and into the medial compartment (2 ml) of the orbit at the medial canthus. Satisfactory anaesthesia coul d be achieved with all of these methods. Additional block because of i nsufficient akinesia of the muscles was required in 12% (18/150) in gr oup R, in 19% (28/150) in group PI, and in 11% (16/150) in PII. The me dial compartment technique (PII) was associated with the highest perce ntage of total akinesia of the muscles and lowest reblock rate. All th ree methods produced sufficient analgesia during surgery and there wer e no differences in the requirements for additional analgesic drugs du ring surgery. It is concluded that the medial compartment technique re presents a good alternative to retrobulbar block.