Caudal block for post-operative pain relief in children after genital operations. A comparison between bupivacaine and morphine.

Twenty-two children formed the basis for a controlled study of the effect and duration of the postoperatively applied caudal block on postoperative pain after genital operations. The purpose of the study was to compare the effect and duration of bupivacaine and morphine. Ten children (Group I, outpatients) underwent circumcision and 12 children (Group II, inpatients) underwent correction of hypospadias. The caudal block failed in one case. Outpatients were discharged after 4-5 h, and the caudal blocks with both bupivacaine and morphine were then still effective. In inpatients, the duration of pain relief was significantly longer using morphine (range 610-2195 min) than using bupivacaine (range 245-515 min). There were no complications of the caudal blocks.