Postoperative analgesia for haemorrhoid surgery

Seventy patients undergoing haemorrhoidectomy under general anaesthesia were randomly allocated to one of five treatment groups in order to compare the effectiveness of various caudal agents in the control of postoperative pain. Four groups were given a caudal injection of either 2% lignocaine, 0.5% bupivacaine, 2% lignocaine + morphine sulphate 4 mg or normal saline + morphine sulphate 4 mg, while the fifth (control) group did not receive an injection. The number of patients requiring postoperative opiates was significantly higher in the lignocaine group than in the morphine (p less than 0.05) and morphine-lignocaine (p less than 0.05) groups. No agent significantly reduced the number requiring opiates. In those who received opiates, the mean analgesic period was 228 minutes in the control group, and was significantly longer following bupivacaine (577 min, p less than 0.01), morphine-lignocaine (637 min, p less than 0.05) and morphine (665 min, p less than 0.0). The mean analgesic period following lignocaine (349 min) was not significantly different from control. The incidence of catheterisation was lowest in those patients who did not receive caudal analgesia.