The experimental study on the time of removal of gastrobiliary duct drainage in primary suture after exploration of common bile duct in dog

Objective To establish an animal model with installation of gastrobiliary duct drainage (GBDD) in primary suture after exploration of common bile duct,to investigate the natuaral history of the healing of bile duct and obtain the safety,appropriate time of removal of GBDD.Methods Twenty-five dogs were randomly divided into control group (n =5) and GBDD group (n =20).The GBDD group was randomly divided into four subgroups,to cholangiography,extubate,and then excised bile duct anastomoses were stained with hematoxylin and eosin (HE),Masson and Scanning electron microscope (SEM) on postoperative day (POD) 3,5,7,9 respectively.Results Two bile leakage cases were found in POD 3 group after removal of the GBDD,no bile leakage case was fund in other groups.The inflammatory cell infiltration of the bile duct anastomoses showed statistical significance among four groups on POD 3 vs 5,7,9 (3.2 ±0.45 vs 2.2 ± 0.45,1.4 ± 0.55,1.2 ± 0.45,all P ＜ 0.05).POD 7 vs 9 showed no statistically significant difference between them (P ＞ 0.05).There were significant difference in index of mucosal healing among POD 3 vs 5,7,9 (1.0 vs 2.2 ±0.45,2.4 ±0.55,2.8 ±0.45,allP ＜0.05),POD 5,7,9 showed no statistically significant difference among them (P ＞ 0.05).POD 5-7,HE staining showed that bile duct wall was thickening;Masson staining showed that the fibroblast distribution was disorderly;SEM showed that port of the bile duct restored with epithelial cell.However,the mucosa of bile duct restored poorly,chronic inflammation lasted for a long time.Conclusion It is safe to remove the GBDD on POD 5-7,there was no bile leakage. Key words: Gastrobiliary duct drainage; Primary suture; Extubation time