A Cochrane review included 10 studies with a total of 721 boys. In studies the age range was given, the boys were aged from 9 months to 13 years. Postoperative analgesia by means of a caudal epidural block was compared with a non-caudal method of analgesia. No difference was seen between caudal and parenteral analgesia in the need for rescue or other analgesia (RR 0.41, 95% CI 0.12 to 1.43; 4 studies, n=235) or in the incidence of nausea and vomiting (RR 0.61, 95% CI 0.36 to 1.05; 4 studies, n=235). No difference in the need for rescue or other analgesia was seen for caudal compared with dorsal nerve penile block (DNPB) (RR 1.25, 95% CI 0.64 to 2.44; 4 studies, n=336). No differences were seen between caudal block and DNPB in the incidence of nausea and vomiting (RR 1.88, 95% CI 0.70 to 5.04; 4 studies, n=334) or individual complications except for motor block (RR 17.00, 95% CI 1.01 to 286.82; 1 study, n=100) and motor or leg weakness (RR 10.67, 95% CI 1.32 to 86.09; 2 studies, n=107). These were significantly more common in the caudal block groups than with DNPB. No differences were seen between caudal and rectal+intravenous analgesia in the need for rescue or other analgesia (RR 0.81, 95% CI 0.51 to 1.27, 2 studies, n=164) or nausea or vomiting (RR 0.88, 95% CI 0.14 to 5.53, 2 studies, n=164).
Comment: The quality of evidence is downgraded by study quality (unclear allocation concealment) and by imprecise results (few patients and wide confidence intervals).