Background Duodenal endoscopic submucosal dissection (ESD) remains technically challenging, with a high risk of severe adverse events. Because exposure of the duodenal post-ESD mucosal defect to pancreatic juice and bile acid reportedly induces delayed perforation and bleeding, we examined whether defect closure using an over-the-scope clip (OTSC) system was useful for preventing postoperative adverse events. Methods From April 2016 to February 2017, a total of 50 consecutive patients with superficial non-ampullary duodenal epithelial tumors (SNADETs) larger than 10 mm, with no more than semi-circumferential spread, were prospectively enrolled in this study. All of the lesions were treated by experienced ESD operators and the post-ESD mucosal defect was closed using OTSCs. Results All of the SNADETs were completely removed by ESD, with an R0 resection rate of 88.0 %. The mean procedure and closure times were 67.3 ± 58.8 minutes and 9.8 ± 7.2 minutes, respectively. Although complete defect closure was achieved in 94.0 % of the patients (47/50), two patients required surgical conversion. Delayed perforation occurred in only one patient (2.1 %), who did not have successful closure of the defect, as misplacement of the OTSC exposed the muscle layer. Meanwhile, delayed bleeding occurred in three patients (6.3 %); however, the bleeding was easily controlled using endoscopic coagulation. The mean duration of postoperative hospitalization was 5.5 ± 7.2 days. Conclusions Prophylactic defect closure using OTSCs may be effective in reducing severe adverse events after duodenal ESD.

Prevention therapy is recommended for lesions >1/2 of the esophageal circumference. Locoregional steroid injection is recommended for lesions >1/2–3/4 of the esophageal circumference and oral steroids are recommended for lesions >1/2 of the subtotal circumference. For lesions of the entire circumference, oral steroid combined with injection steroid is considered. Endoscopic balloon dilatation (EBD) is the first choice of treatment for stricture after esophageal endoscopic submucosal dissection (ESD). Radical incision and cutting or self‐expandable metallic stent can be considered for refractory stricture after EBD. In case of intraoperative perforation during esophageal ESD, endoscopic clip closure should be initially attempted. Surgery is considered for treatment of delayed perforation. Current standard practice for prevention of delayed bleeding after gastric ESD includes prophylactic coagulation of vessels on post‐ESD ulcers and giving proton pump inhibitors. Chronic kidney disease stage 4 or 5, multiple antithrombotic drug use, anticoagulant use, and heparin bridging therapy are high‐risk factors for delayed bleeding after gastric ESD. Intraoperative perforation during gastric ESD is initially managed by endoscopic clip closure. If endoscopic clip closure is difficult, other methods such as over‐the‐scope clip (OTSC), polyglycolic acid (PGA) sheet shielding etc. are attempted. Delayed perforation usually requires surgical intervention, but endoscopic closure by OTSC or PGA sheet may be considered. Resection of three‐quarters of the circumference is a risk factor for stenosis after gastric ESD. Giving prophylactic local steroid injection and/or oral steroid is reported, but effectiveness has not been fully verified as has been done for esophageal stricture. The main management method for gastric stenosis is EBD but it may cause perforation.

Aim To analyze factors involved in procedural failure and to discuss responses to procedural failure by using the outcomes of endoscopic retrograde cholangiopancreatography (ERCP) carried out using a short‐type single‐balloon enteroscope (short SBE) in patients with surgically altered gastrointestinal anatomy. Methods The study sample included patients who underwent ERCP‐related procedures using a short SBE between September 2011 and September 2018 at our hospital. Outcomes, including procedural success rate, were studied retrospectively to analyze the factors involved in procedural failure. Results Analysis included 191 procedures carried out in 121 patients. Procedural success rate was 85.9% with an adverse event rate of 8.4%. Causes of procedural failure included malignant biliary obstruction (odds ratio [OR] 2.89, 95% confidence interval [CI] 1.19–7.25, P = 0.02), first ERCP attempt (OR: 5.32, 95% CI: 1.30–36.30, P = 0.02), and Roux‐en‐Y reconstruction (OR: 0.08, 95% CI: 0.004–0.39, P < 0.001). With regard to the response to failure, in cases of malignant biliary obstruction, reattempted short SBE‐assisted ERCP was difficult because of invasion of the small intestine or papilla. A large number of these cases required alternative treatment (10 of 15 cases, 66.7%) using percutaneous transhepatic biliary drainage (PTBD) or endoscopic ultrasound‐guided biliary drainage (EUS‐BD). Conclusion Endoscopic retrograde cholangiopancreatography using a short SBE is safe and effective, with malignant biliary obstruction being a specific cause of failure. Technical proficiency with different modalities, such as PTBD and EUS‐BD, is necessary to respond to failure in these cases.

BackgroundStricture formation is one of the major complications after endoscopic removal of large superficial squamous cell neoplasms of the esophagus, and local steroid injections have been adopted to prevent it. However, fundamental pathological alterations related to them have not been well analyzed so far. The aim of this study was to analyze the time course of the healing process of esophageal large mucosal defects resulting in stricture formation and its modification by local steroid injection, using an animal model.MethodsEsophageal circumferential mucosal defects were created by endoscopic mucosal dissection (ESD) for four pigs. One pig was sacrificed five minutes after the ESD, and other two pigs were followed-up on endoscopy and sacrificed at the time of one week and three weeks after the ESD, respectively. The remaining one pig was followed-up on endoscopy with five times of local steroid injection and sacrificed at the time of eight weeks after the ESD. The esophageal tissues of all pigs were subjected to pathological analyses.ResultsFor the pigs without steroid injection, the esophageal stricture was completed around three weeks after the ESD on both endoscopy and esophagography. Histopathological examination of the esophageal tissues revealed that spindle-shaped α-smooth muscle actin (SMA)-positive myofibroblasts arranged in a parallel fashion and extending horizontally were identified at the ulcer bed one week after the ESD, and increased contributing to formation of the stenotic luminal ridge covered with the regenerated epithelium three weeks after the ESD. The proper muscle layer of the stricture site was thinned with some myocytes which seemingly showed transition to the myofibroblast layer. By contrast, for the pig with steroid injection, esophageal stricture formation was not evident with limited appearance of the spindle-shaped myofibroblasts, instead, appearance of stellate or polygocal SMA-positive stromal cells arranged haphazardly in the persistent granulation tissue of the ulcer site.ConclusionsProliferation of spindle-shaped myofibroblasts arranged in a parallel fashion is likely to play an important role in stricture formation after circumferential mucosal defects by esophageal ESD, which may be related to the thinning of the proper muscle layer in the healing course of the defects. Local steroid injection seems to be effective to prevent the stricture through the modification of this process.

The Monro-Kellie doctrine states that the interior of the cranium is formed of three main components: blood, fluid and cerebral parenchyma. An increase in the volume of one or more components may increase the intracranial pressure (ICP). This doctrine also affirms that the skull cannot be expanded after the closure of the fontanels. Monro and Kellie's theory has been perfected during the last two centuries. This study leads to a new contribution that proves that even adults' consolidated skulls present volumetric changes as a consequence of ICP variations.

Background and study aims: Despite the clinical advantages of colorectal endoscopic submucosal dissection (ESD), an effective training system, especially for Western endoscopists, has been challenging to establish. Herein, we propose a novel training program using ex vivo animal models and evaluate the learning curve of colorectal ESD trainees without gastric ESD experience. Patients and methods: A total of 80 colorectal lesions were prospectively collected and removed by two novice operators. Before human ESD procedures, they received ESD training using an ex vivo porcine “proximal colon” model, which simulates a lumen with many folds and flexions. To assess the validity of our training system, the self-completion and en bloc R0 resection rates, the operation time, and prevalence of complications were compared between the first and latter period. Moreover the factors associated with prolonged operation time were evaluated. Results: The overall rates of self-completion and en bloc R0 resection were 98 % (78/80) and 100 % (80/80), respectively. The operation time during the first period was significantly longer than that during the latter period (86 ± 50 minutes vs. 60 ± 36 minutes, P = 0.01). Regarding complications, only two cases of perforations and delayed hemorrhage were observed during the first period; however, all of the complications were successfully managed endoscopically. The presence of fibrosis was identified as a significant independent predictor of a prolonged operation time during the first period (coefficient, 5.90; 95 %CI, 2.36 – 9.44, P = 0.002). Conclusions: Our trainees achieved high rates of self-completion and R0 resection without severe complications even during the first 20 cases, suggesting that our training programs using ex vivo animal models are useful for trainees without gastric ESD experience.Study registration: UMIN000013566

The tumor typing based on NBI was useful for the endoscopic differentiation of gastric adenoma and well-differentiated adenocarcinoma.

These results suggest that NBI magnifying endoscopy may be useful not only in the diagnosis but also in the evaluation of the response to eradication therapy of MALT lymphoma of the stomach.