Pharmacological strategies to reduce pruritus during postoperative epidural analgesia after lumbar fusion surgery - a prospective randomized trial in 150 patients

BACKGROUND Epidural analgesia with bupivacain, epinephrine and fentanyl provides excellent pain control after lumbar fusion surgery, but pruritus and motor block are frequent side effects. Theoretically epidural ropivacain combined with oral oxycodone could decrease the incidence of these side effects. The two regimens were compared in a prospective randomized trial. PATIENTS AND METHODS 150 patients (87 women) treated with posterior instrumented lumbar fusion were included. The mean age was 51 +/- 11 years. 76 were randomized to bupivacain, epinephrine and fentanyl (group B) and 74 to ropivacain and oxycodone (group R). Pruritus, motor block and pain were measured 6 hours after surgery, thereafter 6 times per day for 5 days. Any pain breakthrough episode was registered whenever it occurred. RESULTS The epidural treatment could be performed in 143 patients (72 in group B and 71 in group R). Disturbing pruritus occurred in 53 patients in group B compared to 12 in group R (p < 0.0001). Motor blockade was most frequent on day 1, occurring in 45% of the patients with no difference between the groups. Both regimes gave good pain control with average VAS under 40, but the pain relief was statistically better in group B. The number of pain breakthrough episodes did not differ between the groups. CONCLUSIONS Pruritus could be reduced with a combination of epidural ropivacain and oral oxycodone, at the price of a slightly higher pain level. Ropivacaine was not found to be superior to bupivacaine with regard to motor blocks.