Comparison of 0.5% ropivacaine and 0.5% bupivacaine in lumbar epidural anaesthesia for lower limb orthopaedic surgery

The purpose of this study was to compare the epidural use of 0.5% ropivacaine and 0.5% bupivacaine in patients undergoing lower limb orthopaedic surgery. In double-blind, randomized multi-centre study involving 67 patients, thirty-two patients received 20 ml of 0.5% ropivacaine and 35 patients received 20 ml of 0.5% bupivacaine at the L2,3 or L3,4 interspace. Parameters measured were the onset time, duration and spread of sensory block, the onset time, duration and degree of motor block, the quality of anaesthesia and the heart rate and blood pressure profile during block onset. Four patients (3 ropivacaine, 1 bupivacaine) were excluded from the study due to technical failure of the block. The onset and duration of analgesia at the T10 dermatome (median, interquartile range) was 10 (5-15) minutes and 3.5 (2.7-4.3) hours respectively for ropivacaine, and was 10 (6-15) minutes and 3.4 (2.5-3.8) hours respectively for bupivacaine. Maximum block height (median, range) was T6 (T2-T12) for ropivacaine and T6 (C7-T10) for bupivacaine. Nine patients receiving ropivacaine and eight patients receiving bupivacaine developed no apparent motor block. The incidence of complete motor block (Bromage grade 3) was low in both groups, being 4/27 for ropivacaine and 6/34 for bupivacaine. In the ropivacaine group, motor and sensory block were judged to be satisfactory in 78% of patients. In the pubivacaine group, motor and sensory block were judged to be satisfactory in 71% and 62% of patients respectively. Cardiovascular changes were similar in both groups. No statistical differences were found between the two group regarding any of the study parameters.