[Study on the application of self-fixing and self-detachable drainage stent in pancreaticojejunostomy]

Objectives: To evaluate the efficacy and safety of the self-fixing and self-detachable drainage stent in pancreaticojejunostomy and to provide supportive data for the follow clinical trials. Methods: This is an experimental research in animals which completed from February 2022 to September 2022. A self-fixing and self-detachable pancreaticojejunostomy drainage stent was designed for Hong's pancreaticojejunostomy technique based on the theory of "fistula healing" in pancreaticojejunostomy. Ten biocompatibility tests were completed in vitro before this study. Twenty-five Bama minipigs were selected and double-ligated in the neck of the pancreas to dilate the distal main pancreatic duct. Twenty-three of them were successfully modelled and divided into three groups by a stratified random method: pancreaticojejunostomy drainage stent group (referred to as stent group) with 11 pigs, pancreatic duct to jejunal mucosa anastomosis group (referred to as manual suture group) with 8 pigs, sham operation group with 4 pigs. The anastomic time,amylase content in postoperative abdominal drainage fluid and the tolerable pressure value of pancreaticojejunostomy were compared between the stent group and the manual suture group. An abdominal X-ray fluoroscopy examination was adopted to detect the detach time of the stent. A postoperative pathological examination was performed to verify the healing time,the type of treatment and the stricture rate of pancreaticojejunostomy. Quantitative data was analyzed by independent sample t-test. The classified data were analyzed by Fisher's exact test. Results: There were no significant differences in the diameter of the pancreatic duct and pancreatic texture,the time of pancreaticojejunostomy,the amylase content in postoperative peritoneal drainage fluid,and the tolerable pressure value of the pancreaticojejunostomy between the stent group and the manual suture group(all P>0.05). Abdominal X-ray fluoroscopy showed that the stents gradually detached and were removed from the body 21 days after operation,and all stents were detached in the follow 3 months after operation. Pancreaticojejunostomy healed 7 days after operation based on fistula formation in the stent group,and 14 days in the manual suture group. The incidence of anastomotic stricture within 35 days after operation was 2/8 in the stent group and 6/8 in the manual suture group (Fisher's exact test: P=0.132). Conclusion: The stent method is safer and simpler than the manual suture method in pancreaticojejunostomy of Bama minipigs, with shorter anastomotic healing time and lower stricture rate.