The Animal Experimental Study Of Gastrojejunostomy By Stent

Introduction:The creation of anastomoses between various parts of the gastrointestinal tract is a major task in the daily practice of oncological,reconstructive and transplant surgery. An ideal technique of anastomosis should be with strong anastomotic strength,simple procedure and short anastomosis time.Simple anastomosis procedure is a trend of this procedure.In this study,we developed a new technique of gastrointestinal anastomosis with a degradable stent.The experiment was randomized, placebo-controlled.The stent anastomosis was evaluated concerning anastomosis time, anastomotic bursting pressure,hydroxyproline concentration and histopathology in comparison to the shandsewn anastomosis using a simple gastrojejunostomy model through ligating and blockading the pylorus of Bama minipigs with a silk.Our study was designed to evaluate the security,feasibility and reliability of using a stent to perform gastrojejunostomy in an animal experiment,to explore the advantages and disadvantages of gastrojejunostomy by stent,to improve this new technique,to provide scientific,reliable theoretical and practical basis for clinical trial of the biodegradable anastomosis stents and to study the prospects of the new technique in clinical application.Methods:A total of 20 Bama minipigs were included in the study.All pigs were divided into two groups randomly and there were 10 pigs in each group.Animals were anaesthetized and access to the peritoneal cavity was obtained by a median laparotomy.The pylorus was ligated and blockaded with a silk.In the control group, handsewn anastomoses using a continuous single-layer suture with 4-0 absorbable suture were performed.In the study group,the anastomoses were constructed with stent.On the 10th postoperative day X-ray observation was performed with diluted methylglucamine diatrizoate injected orally via catheter.On day 3 or 14 postoperatively animals were anaesthetized again and a relaparotomy were performed through the previous incision.After exploring abdominal cavity carefully,determined anastomotic bursting pressure using in vivo method,then detached the adhesions around the anastomosis,and the anastomotic segment was excised for 0.5cm wide tissue sample.Half of the anastomotic sample was stored at -80℃for hydroxyproline assay,and half was immediately fixed in 10%formaldehyde solution for histopathologic examination.Results:1.Anastomosis time:Anastomosis time in stent group(11.9±1.9min)was significantly shorter than in handsewn group(21.7±2.3min;P＜0.01).2.Imageology:Injecting diluted methylglucamine diatrizoate,showed that gastric body developed,the contrast agent passed through the anastomosis smoothly and afferent loop and efferent loop developed well;no diffusion of contrast agent was seen in the abdominal cavity.Under the dynamic perspective,no contrast agent through the pyloric was seen.3.General observation:On the third day after operation,the anastomotic alignment was good in both handsewn and stent groups;on the 14th day macroscopic appearance of the anastomotic site was always good in both handsewn and stent groups even though a circular fibrotic ring was always present.4.Anastomotic bursting pressure:On the third day after operation,the anastomotic bursting pressure in stent group(18.2±1.6kPa)was significantly higher than that in handsewn group(11.7±3.0kPa;P＜0.05);on the 14th day,the anastomotic bursting pressure had no difference between the two groups.5.Hydroxyproline concentration:On the third day or 14th day after operation,the hydroxyproline concentration had no difference between stent group and handsewn group.6.Histopathology:On the third day after operation,the anastomotic inflammation was obvious and granulocytes were the predominant cell type in both handsewn and stent groups.On the 14th day,fibrous tissue hyperplasia was obvious and there was granulation on anastomotic line with abundant inflammatory cell infiltration and lymphocytes were the predominant cell type in both stent and handsewn groups; microscopic studies showed a complete mucosal epithelial lining with reepithelialization of the mucosa in both handsewn and stent groups.Conclusions:Gastrojejunostomy by stent is a safe and feasible technique,can obviously increase early anastomotic bursting pressure and conduce to prevention of leakage. Gastrojejunostomy by stent is simple,convenient,quick,efficient and easy to grasp.