Abstract:Objective To investigate the safety and effect of coutinuous caudal anesthesia for postoperative PCA（patient\|controlled analgesia）after operation of anal disease and the clinical effect of preventing urinary retention by using neostigmine. Methods Two hundred twenty\|enght patients with ASA ⅠorⅡ underwent operation of anal disease were randomly divided into two groups：A group and B group.160 patients of anal operation with coutinuous caudal anesthesia and postoperative PCA were taken as A group(82 patients were gived an intramuscular injection of 10 μg/kg neostigmine after operation were takes as A1 group and 78 patients were not gived neostigmine after operation were takes as A2 group).Homochronous,68 patients of anal operation had a single caudal anesthesia and postoperative analgesia of traditional methods were taken as control B group(40 patients who were gived an intramuscular injection of 10 μg/kg neostigmine after operation were taken as control B1 group.28 patients were not gived neostigmine after operation were takes as B2 group).15-20 ml 1.5% lidocaine was used for anesthesia in both groups.Only single dose of PCA technical parameters was used in A group for analgesia,drug was 0.18% ropivacaine,6-7 ml every time,needing 90mins totally.10 μg/kg neostigmine was used after operation in A1and B1 groups.Analgesia effect,sleep status and urinary retention were observed in 48 hours after operation.Results  A group was superior to B group in postoperative analgesia,sleep status,and urinary retention(P＜0.05).An intramuscular injection of neostigmine after operation was not significant difference(P＞0.05).Conclusion Continuous caudal anesthesia and postoperative PCA which was used for patient of anal disease proved to be a safe and effective,and also few adverse effects method,but an intramuscular injection of neostigmine after operation could not effectively prevent urinary retention.