Design and evaluation of a novel anti-reflux biliary stent with cone spiral valve

Endoscopic placement of biliary stent is a well-established palliative treatment for biliary obstruction. However, duodenobiliary reflux after stent placement has been a common problem which may lead to dreadful complications. This paper designed a novel anti-reflux biliary stent with a cone spiral valve. Fluid-Structure Interaction (FSI) simulations were established to evaluate the efficiency of the anti-reflux stent comparing with a clinically applied standard stent. According to the stress distribution of the valve, the fatigue performance in the stress concentration area was analyzed. The results show that when the antegrade flow through the valve, the cone spiral valve could stretch and open to realize adequate drainage under the normal physiological pressure of biliary tract; When the duodenal reflux through the valve, the valve would be compressed and close with a result of nearly zero at the outlet flow rate. Furthermore, the anti-reflux stent achieved improved radial mechanical performance with 2.7 times higher radial stiffness than standard stent. Finite element analysis (FEA) also indicates that compared with the standard stent, the addition of the anti-reflux valve had little negative effect on flexibility of the stent. Fatigue analysis results showed that the valve was reliable. This research provides the new stent with a cone spiral valve and proves that it is technically feasible and effective for preventing the duodenobiliary reflux while ensuring the antegrade bile flow without compromising the other biomechanical performances.

Ascending Cholangitis due to Heavy Lifting

Gallstone disease is the most common risk factor for cholangitis. In an anatomically normal bile duct system, cholangitis does not occur without the presence of stones. Endoscopic retrograde cholangiography with papillotomy and stone extraction is a well-established curative therapy for gallstones in the common bile duct. More important, papillotomy prevents recurrent episodes. The present case report describes a 73-year-old male with recurring cholangitis in a clear bile duct system after previous papillotomy. An etiology of duodenal reflux into the common bile duct due to heavy lifting is proposed.

Features gastroduodenal pathology in military age patients with malnutrition

Background.Digestive diseases are a leading cause of body weight deficit and has a leading position among general morbidity in young patients.Purpose.To analyze the pathology of the upper digestive tract in young men with a low body weight.Material and methods.193 young men aged 16-27 y.o. (mean age 20,3±2,2 years) with a mean body mass index (BMI) 17,8±2,4 kg/m2were examined. Erosive lesions of the stomach were found in 18,8% (n=36) and erosive lesions of the duodenum – in 16,1% (n=31). Ucer of duodenum were found in 11,4% (n=22) and none of stomach. Duodenal reflux were found in (51,8%;n=100) and every fourth was combined with erosive gastritis. Histological examination of stomach revealed an inflammation in all cases. Atrophic changes in the antral stomach were detected in 11% (n=6) of the cases. All cases of atrophy accompanied by HP colonization. In the group with normal BMI the prevalence of cardia failure, erosive lesions of the esophagus, stomach and duodenum were founded. In the same group there were prevalence of stomach inflammation by histology (44%). The patients with low BMI (hypotrophy 1 degree) have less erosion and inflammation compare to patients with normal BMI and hypotrophy 2-3 degrees.Conclusions.1. Stomach inflammation were revealed in the majority of young men with low BMI. Atrophic changes of gastric antrum associated with HP infection were found in 10% of cases. 2. Erosive lesions of the esophagus, stomach and duodenal are associated with the BMI. This finding allows use the BMI as an integral indicator of the severity of the inflammation of stomach and duodenum. Erosive lesions of the upper digestive tract are found predominantly in patients with normal BMI.

Evaluation of the heme oxygenase-1 expression in esophagitis and esophageal cancer induced by different reflux experimental models and diethylnitrosamine

PURPOSE: To study the expression of heme-oxygenase-1 (HO-1), an enzyme induced by oxidative stress, in specimens obtained from an experimental model in rats that evaluated the role of gastric and duodenal reflux in esophageal carcinogenesis. METHODS: Esophageal specimens embedded in paraffin obtained from different experimental groups of rats were used for immunohistochemistry analysis of HO-1 expression. The rats had been divided into the following groups and were killed after 22 weeks: (1) cardioplasty to induce acid reflux; (2) esophagoduodenal anastomosis to induce duodenal reflux; (3) no treatment; (4) cardioplasty + diethylnitrosamine (DEN); (5) esophagoduodenal anastomosis + DEN; and (6) DEN. The study sample comprised 3 specimens from each group with the most severe histopathological lesions found on each study branch. RESULTS: The expression of HO-1 was seen only in rat specimens submitted to esophagoduodenal anastomosis (Groups 2 and 5), and the analysis of mean fluorescence intensity revealed a significant increase of HO-1 expression (4.8 and 4.6 fold, respectively) when compared with the control group (Group 3) (p<0.05). The main target for HO-1 induction was the inflammatory cells inside the tumor or in subepithelial areas. Rats exposed to gastric reflux had no HO-1 expression. CONCLUSION: Reflux esophagitis induced by reflux of duodenal contents, which provoked considerable oxidative stress, may play an important role in esophageal carcinogenesis. Acid reflux did not induce oxidative stress in this experimental model.

Carcinogenesis of the upper gastrointestinal tract induced by N-methyl-N'-nitro-nitrosoguanidine and reflux of duodenal contents in the rat

PURPOSE: To investigate the combined effects of reflux of duodenal contents through the pylorus and treatment with N-methyl-N'-nitro-nitrosoguanidine (MNNG) on the development of lesions in the glandular stomach, at the gastrojejunal anastomosis and in the forestomach of rats. METHODS: Eighty Male Wistar rats were divided into 4 groups: G1: MNNG + Reflux, G2: Reflux, G3: MNNG and G4: Gastrostomy. MNNG was given in the drinking water (100 mg/ml) for 12 weeks and then two groups (G1 and G2) were submitted to a gastrojejunal anastomosis followed by section of the afferent loop and suture of both stumps to allow reflux of duodenal contents through the pylorus. The animals were sacrificed 18 and 36 weeks after surgery. The lesions obtained in the antral mucosa, at the gastrojejunal anastomosis and in the forestomach were analysed histologically. RESULTS: Duodenal reflux induced proliferative lesions at both glandular and squamous mucosa of the stomach. In the antrum, adenomatous hyperplasia (AH) was observed in 20% and 50% of the animals at the 18th and 36th weeks respectively. Aditionally 85% of the animals presented AH at the gastrojejunal anastomosis and 60% developed squamous hyperplasia at the squamous portion of the stomach. MNNG treatment plus duodenal reflux enhanced the development of malignant tumors at both glandular and squamous mucosa, since there were 30% of antral adenocarcinomas and 45% of squamous carcinomas at the 18th week and the frequency of these malignant tumors rose to 50% in the antrum and 65% in the squamous mucosa at the 36th week. CONCLUSION: The reflux of duodenal contents through the pylorus enhanced the development of proliferative lesions, benign and malignant, in the glandular stomach and in the forestomach of rats.