Background and objectives Prophylactic pancreatic duct stent placement effectively reduces post-endoscopic retrograde cholangiopancreatography pancreatitis in high-risk patients, but the optimal stent remains unclear. We modified a 5-Fr, 3 cm pancreatic stent by removing the flange on the pancreatic side and compared the rate of spontaneous dislodgement and complications with the ordinary stent. Methods This was a randomized controlled trial at six tertiary endoscopic centers. Patients deemed high risk for post-endoscopic retrograde cholangiopancreatography pancreatitis randomly received modified or ordinary pancreatic stent. The primary outcome was spontaneous stent dislodgement at five days and 14 days. Secondary outcomes were the success rate of stent placement and complications. Results A total of 276 patients were randomly assigned to receive modified stents (mS group) and ordinary stents (oS group). The placement of a pancreatic stent was successful in all 276 patients. There were no significant differences between groups with respect to age, sex, major diagnosis, or indications for stenting. At five days the spontaneous dislodgement rate was 47.72% for the mS group and 15.67% for the oS group ( p<0.001); at 14 days the rates were 84.21% and 42.65%, respectively ( p < 0.001). Post-endoscopic retrograde cholangiopancreatography pancreatitis occurred in 6.52% of all patients. There were no significant differences regarding the incidences of post-endoscopic retrograde cholangiopancreatography pancreatitis, hemorrhage or fever. Conclusions The modified short 5-Fr stent has a higher spontaneous dislodgement rate than ordinary pancreatic stent, thus obviating the need for endoscopic removal. The modified pancreatic stent does not increase the incidence of post-endoscopic retrograde cholangiopancreatography pancreatitis or other complications. The endoscopist can consider removing the flange on the pancreatic duct side for prophylactic pancreatic duct manipulation.

PurposeThis study was undertaken to establish a rabbit esophageal tumor model for mimicking human esophageal squamous carcinoma (ESC) by endoscopic and surgical implantation of VX2 tumors.MethodsFragments of a VX2 tumour were endoscopically implanted in the submucosal layer of the thoracic esophagus of 32 New Zealand white rabbits, while 34 animals received surgical implantation into the muscular layer. Then, the animals were studied endoscopically and pathologically. The safety and efficiency of the two methods and the pathological features of the animal models were analyzed.ResultsBoth the endoscopic and the surgical method had a relatively high success rate of tumor implantation [93.7% (30/32) vs. 97.1% (33/34)] and tumor growth [86.7% (26/30) vs. 81.8% (27/33)], and the variation in the results was not statistically significant (P>0.05). Compared with those produced by the surgical method, the models produced by the endoscopic method had a higher rate of severe esophageal stricture [61.5% (16/26) vs. 29.6% (8/27)] and of intra-luminal tumor growth [73.1% (19/26) vs. 37.0% (10/27)], and had a lower rate of tumor invasion of adjacent organs [53.8% (14/26) vs. 81.5% (22/27)]; all of these results were statistically significant (P<0.05). However, the difference in the survival time and the rates of tumor regional/distant metastasis [38.5% (10/26) vs. 51.8% (14/27)] between the two methods were not statistically significant (P>0.05).ConclusionThe endoscopic and surgical methods are both safe and effective for establishment of VX2 tumors in the rabbit esophagus. The models produced by the two methods have different pathologic features mimicking that of human ESC. We recommend the models for studies on surgical procedures and minimally invasive treatments.

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BackgroundStents are recommended in patients with dysphagia caused by esophageal stricture, but an ideal stent does not currently exist. Thus, studies on new esophageal stents are necessary, and suitable animal models are desperately needed for these studies. The aim of this study was to establish a model of malignant esophageal stricture in rabbit for studies on stent innovation.MethodsA total of 38 New Zealand white rabbits were used in this study. Using the endoscopic submucosal injection technique, VX2 fragments were inoculated into the submucosal layer of the rabbit thoracic esophagus, and an endoscopic follow-up was subsequently performed to observe the tumor development and progression. The self-expandable metal stents were randomly deployed in rabbits with severe esophageal stricture to investigate the safety and feasibility of the animal models for stenting.ResultsAn endoscopic implantation procedure for VX2 tumors was completed in 34/38 rabbits, and tumor development was confirmed in 30/34 animals. The success rate of the endoscopic implantation and tumor development were 89.4% (95% CI, 79.6% to 99.2%) and 88.2% (95% CI, 76.9% to 99.5%) respectively. During the endoscopic follow-up period, severe esophageal stricture occurred in 22/30 rabbits with a rate of 73.3% (95% CI, 57.5% to 89.1%), and 12/22 models received stent placement. During and after stent implantation, no severe stent-related complication or mortality occurred in the animal models. The rabbits that received stent placement survived longer than those without stent implantation (the mean survival time: 53.9 days versus 40.3 days, P = 0.016).ConclusionThe endoscopic method is a safe and effective method for establishing a malignant esophagostenosis model in rabbits. This model can simulate the human body environment for stent deployment and is an excellent tool for the study of stent innovation for the treatment of esophageal cancer.