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Background: Liver transplantation is the only curative treatment of end-stage liver disease. Unfortunately, a significant number of patients on the organ waitlist die waiting for an organ. Living-donor liver transplantation (LDLT) is an approach that has been used to expand organ availability. Although LDLT has excellent outcomes, biliary complications remain a significant drawback. This meta-analysis aimed to precisely assess the predictors of biliary stricture and leak after LDLT., Methods: PubMed, Embase, and Web of Science databases were searched from inception to January 2024. Only studies that used a multivariate model to assess risk factors for post-LDLT biliary stricture or leak in adult participants were included. Studies reporting unadjusted risk factors were excluded. Pooled adjusted odds ratios (ORs) and pooled hazard ratios (HRs) with 95% CIs for risk factors reported in ≥2 studies were obtained within a random-effects model., Results: Overall, 22 studies with 9442 patients who underwent LDLT were included. The post-LDLT biliary stricture rate was 22%, whereas the post-LDLT biliary leak rate was 14%. In addition, 13 unique risk factors were analyzed. Postoperative bile leak (OR, 4.10 [95% CI, 2.88-5.83]; HR, 3.88 [95% CI, 2.15-6.99]) was the most significant predictor of biliary stricture after LDLT. Other significant predictors of biliary stricture after LDLT were right lobe graft (OR, 2.56; 95% CI, 1.23-5.32), multiple ducts for anastomosis (OR, 1.62; 95% CI, 1.08-2.43), ductoplasty (OR, 2.07; 95% CI, 1.36-3.13), ABO incompatibility (OR, 1.45; 95% CI, 1.16-1.81), and acute cellular rejection (OR, 4.10; 95% CI, 2.88-5.83). Donor bile duct size (HR, 0.82; 95% CI, 0.74-0.91; P = .001, I 2 = 0%) was found to be significantly associated with reduced risk of post-LDLT biliary stricture. Donor age, recipient age, recipient male sex, and duct-to-duct anastomosis were not associated with an increased risk of post-LDLT biliary strictures. Multiple ducts for anastomosis (OR, 1.86; 95% CI, 1.43-2.43) was a significant predictor of post-LDLT biliary leak. Recipient age, warm ischemia time, and duct-to-duct anastomosis were not associated with an increased risk of post-LDLT biliary leak., Conclusion: In this meta-analysis, 7 unique risk factors were shown to be predictive of post-LDLT biliary stricture, one of which was associated with both post-LDLT biliary stricture and leak. Donor bile duct size was found to be protective against post-LDLT biliary strictures. Identifying reliable predictors is crucial for recognizing high-risk patients. This approach can facilitate the implementation of preventive measures, surveillance protocols, and targeted interventions to reduce the incidence of biliary strictures after LDLT., Competing Interests: Declaration of competing interest M.A.G. is a consultant of Boston Scientific and Ambu and receives research support from Olympus and Cook Medical. The other authors declare no competing interests., (Copyright © 2024 Society for Surgery of the Alimentary Tract. Published by Elsevier Inc. All rights reserved.)

Purpose: We have previously developed grading metrics to objectively measure endoscopist performance in endoscopic sleeve gastroplasty (ESG). One of our primary goals is to automate the process of measuring performance. To achieve this goal, the repeated task being performed (grasping or suturing) and the location of the endoscopic suturing device in the stomach (Incisura, Anterior Wall, Greater Curvature, or Posterior Wall) need to be accurately recorded., Methods: For this study, we populated our dataset using screenshots and video clips from experts carrying out the ESG procedure on ex vivo porcine specimens. Data augmentation was used to enlarge our dataset, and synthetic minority oversampling (SMOTE) to balance it. We performed stomach localization for parts of the stomach and task classification using deep learning for images and computer vision for videos., Results: Classifying the stomach's location from the endoscope without SMOTE for images resulted in 89% and 84% testing and validation accuracy, respectively. For classifying the location of the stomach from the endoscope with SMOTE, the accuracies were 97% and 90% for images, while for videos, the accuracies were 99% and 98% for testing and validation, respectively. For task classification, the accuracies were 97% and 89% for images, while for videos, the accuracies were 100% for both testing and validation, respectively., Conclusion: We classified the four different stomach parts manipulated during the ESG procedure with 97% training accuracy and classified two repeated tasks with 99% training accuracy with images. We also classified the four parts of the stomach with a 99% training accuracy and two repeated tasks with a 100% training accuracy with video frames. This work will be essential in automating feedback mechanisms for learners in ESG., (© 2024. CARS.)

Background and Aims: Extracorporeal shock wave lithotripsy (ESWL) is performed to fragment large main pancreatic duct (MPD) stones in symptomatic patients. Subsequent endoscopic retrograde cholangiopancreatography (ERCP) is often performed to clear the stone fragments. Edema of surrounding tissue after ESWL theoretically affects the ability to perform ERCP. However, the optimal timing of ERCP after ESWL is not clearly defined. The aim of this study is to determine the efficacy and safety of same-day ERCP after ESWL and to determine if the timing of ERCP after ESWL affects outcomes., Methods: This is a retrospective study of consecutive patients from January, 2013 to September, 2019 who received ESWL for MPD stones at our center. Included patients received subsequent same-day ERCP under the same general anesthesia session or later session ERCP (1-30 days after ESWL). Demographics, anatomical findings, history, and outcomes were collected. Success was defined as complete or near complete (> 80%) stone fragmentation with clearance., Results: 218 patients were treated with ESWL and subsequent ERCP. 133 (61.0%) received ERCP on the same day immediately after ESWL, while 85 (39.0%) returned for ERCP at a later day (median 3.0 days after ESWL). Baseline characteristics demonstrated patients who received same-day ERCP had a higher rate of pain at baseline (94.7% vs 87.1%, p = 0.045). Main outcomes demonstrated an overall successful MPD stone clearance rate of 90.4%, with similar rates between same-day ERCP and later session ERCP (91.7% vs 88.2%, p = 0.394). Additionally, successful cannulation at ERCP, adverse events, and post-procedure admission rates were similar., Conclusions: Delaying ERCP to allow peripancreatic tissue recovery after ESWL does not affect outcomes. Same-day ERCP after ESWL is safe and effective., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: We previously developed grading metrics for quantitative performance measurement for simulated endoscopic sleeve gastroplasty (ESG) to create a scalar reference to classify subjects into experts and novices. In this work, we used synthetic data generation and expanded our skill level analysis using machine learning techniques., Methods: We used the synthetic data generation algorithm SMOTE to expand and balance our dataset of seven actual simulated ESG procedures using synthetic data. We performed optimization to seek optimum metrics to classify experts and novices by identifying the most critical and distinctive sub-tasks. We used support vector machine (SVM), AdaBoost, K-nearest neighbors (KNN) Kernel Fisher discriminant analysis (KFDA), random forest, and decision tree classifiers to classify surgeons as experts or novices after grading. Furthermore, we used an optimization model to create weights for each task and separate the clusters by maximizing the distance between the expert and novice scores., Results: We split our dataset into a training set of 15 samples and a testing dataset of five samples. We put this dataset through six classifiers, SVM, KFDA, AdaBoost, KNN, random forest, and decision tree, resulting in 0.94, 0.94, 1.00, 1.00, 1.00, and 1.00 accuracy, respectively, for training and 1.00 accuracy for the testing results for SVM and AdaBoost. Our optimization model maximized the distance between the expert and novice groups from 2 to 53.72., Conclusion: This paper shows that feature reduction, in combination with classification algorithms such as SVM and KNN, can be used in tandem to classify endoscopists as experts or novices based on their results recorded using our grading metrics. Furthermore, this work introduces a non-linear constraint optimization to separate the two clusters and find the most important tasks using weights., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Endoscopic sleeve gastroplasty (ESG) is a minimally invasive endoscopic weight loss procedure used to treat obesity. The long-term goal of this project is to develop a Virtual Bariatric Endoscopy (ViBE) simulator for training and assessment of the ESG procedure. The objectives of this current work are to: (a) perform a task analysis of ESG and (b) create metrics to be validated in the created simulator., Methods: We performed a hierarchical task analysis (HTA) by identifying the significant tasks of the ESG procedure. We created the HTA to show the breakdown and connection of the tasks of the procedure. Utilizing the HTA and input from ESG experts, performance metrics were derived for objective measurement of the ESG procedure. Three blinded video raters analyzed seven recorded ESG procedures according to the proposed performance metrics., Results: Based on the seven videos, there was a positive correlation between total task times and total performance scores (R = 0.886, P = 0.008). Endoscopists expert were found to be more skilled in reducing the area of the stomach compared to endoscopists novice (34.6% reduction versus 9.4% reduction, P = 0.01). The mean novice performance score was significantly lower than the mean expert performance score (34.7 vs. 23.8, P = 0.047). The inter-rater reliability test showed a perfect agreement among three raters for all tasks except for the suturing task. The suturing task had a significant agreement (Inter-rater Correlation = 0.84, Cronbach's alpha = 0.88). Suturing was determined to be a critical task that is positively correlated with the total score (R = 0.962, P = 0.0005)., Conclusion: The task analysis and metrics development are critical for the development of the ViBE simulator. This preliminary assessment demonstrates that the performance metrics provide an accurate assessment of the endoscopist's performance. Further validation testing and refinement of the performance metrics are anticipated., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background and Aims: Endoscopic management of large main pancreatic ductal (MPD) stones often require treatment with lithotripsy. Extracorporeal shock wave lithotripsy (ESWL) has been the mainstay therapy, and single-operator pancreatoscopy with intraductal (intracorporeal) lithotripsy (SOPIL) is an emerging technique. However, no comparative studies between these techniques exist. We therefore aimed to compare ESWL to SOPIL for the treatment of large MPD stones., Methods: This is a retrospective cohort study comparing patients who were treated with ESWL or SOPIL from September 2013 to September 2019 at a single tertiary center. Logistic regression was performed to identify factors associated with technical success and efficient stone clearance (≤ 2 procedures to clear stones)., Results: There were 240 patients who were treated with ESWL and 18 treated with SOPIL. The overall technical success rate of stone clearance was 224/258 (86.8%), which was similar between the ESWL and SOPIL groups (86.7% vs 88.9%, p = 1.000). A SOPIL approach required fewer total procedures (1.6 ± 0.6 vs 3.1 ± 1.5, p < 0.001) and less aggregate procedure time (101.6 ± 68.2 vs 191.8 ± 111.6 min, p = 0.001). Adverse event rates were similar between the groups (6.3% vs 5.6%, p = 1.000). The use of SOPIL was independently associated with greater efficiency compared to ESWL (OR 5.241 [1.348-20.369], p = 0.017). Stone size > 10 mm was associated with less efficient stone clearance (OR 0.484 [0.256-0.912], p = 0.025)., Conclusion: Both ESWL and SOPIL are safe and effective endoscopic adjunct modalities for treating large pancreatic duct stones. SOPIL is an emerging alternative to ESWL that is potentially more efficient for lithotripsy and MPD stone clearance., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: One of the major impediments to the proliferation of endoscopic submucosal dissection (ESD) training in Western countries is the lack of sufficient experts as instructors. One way to address this gap is to develop didactic systems, such as surgical simulators, to support the role of trainers. Cognitive task analysis (CTA) has been used in healthcare for the design and improvement of surgical training programs, and therefore can potentially be used for design of similar systems for ESD., Objective: The aim of the study was to apply a CTA-based approach to identify the cognitive aspects of performing ESD, and to generate qualitative insights for training., Materials and Methods: Semi-structured interviews were designed based on the CTA framework to elicit knowledge of ESD practitioners relating to the various tasks involved in the procedure. Three observations were conducted of expert ESD trainers either while they performed actual ESD procedures or at a training workshop. Interviews were either conducted over the phone or in person. Interview participants included four experts and four novices. The observation notes and interviews were analyzed for emergent qualitative themes and relationships., Results: The qualitative analysis yielded thematic insights related to four main cognition-related categories: learning goals/principles, challenges/concerns, strategies, and decision-making. The specific insights under each of these categories were systematically mapped to the various tasks inherent to the ESD procedure., Conclusions: The CTA approach was applied to identify cognitive themes related to ESD procedural tasks. Insights developed based on the qualitative analysis of interviews and observations of ESD practitioners can be used to inform the design of ESD training systems, such as virtual reality-based simulators.

Background: ESD is an endoscopic technique for en bloc resection of gastrointestinal lesions. ESD is a widely-used in Japan and throughout Asia, but not as prevalent in Europe or the US. The procedure is technically challenging and has higher adverse events (bleeding, perforation) compared to endoscopic mucosal resection. Inadequate training platforms and lack of established training curricula have restricted its wide acceptance in the US. Thus, we aim to develop a Virtual Endoluminal Surgery Simulator (VESS) for objective ESD training and assessment. In this work, we performed task and performance analysis of ESD surgeries., Methods: We performed a detailed colorectal ESD task analysis and identified the critical ESD steps for lesion identification, marking, injection, circumferential cutting, dissection, intraprocedural complication management, and post-procedure examination. We constructed a hierarchical task tree that elaborates the order of tasks in these steps. Furthermore, we developed quantitative ESD performance metrics. We measured task times and scores of 16 ESD surgeries performed by four different endoscopic surgeons., Results: The average time of the marking, injection, and circumferential cutting phases are 203.4 (σ: 205.46), 83.5 (σ: 49.92), 908.4 s. (σ: 584.53), respectively. Cutting the submucosal layer takes most of the time of overall ESD procedure time with an average of 1394.7 s (σ: 908.43). We also performed correlation analysis (Pearson's test) among the performance scores of the tasks. There is a moderate positive correlation (R = 0.528, p = 0.0355) between marking scores and total scores, a strong positive correlation (R = 0.7879, p = 0.0003) between circumferential cutting and submucosal dissection and total scores. Similarly, we noted a strong positive correlation (R = 0.7095, p = 0.0021) between circumferential cutting and submucosal dissection and marking scores., Conclusions: We elaborated ESD tasks and developed quantitative performance metrics used in analysis of actual surgery performance. These ESD metrics will be used in future validation studies of our VESS simulator.

Background: Endoscopic submucosal dissection (ESD) is increasingly being used in Asia as a minimally invasive therapy to eradicate large laterally spreading superficial tumors in the colon. To date, the learning curve and effectiveness of ex vivo simulators in colonic ESD training remain unclear. The aim of the study is to determine the learning curve of colonic ESD in an ex vivo simulator., Methods: We conducted a prospective study of colon ESD in ex vivo porcine colons in a prototype simulator. Three endoscopists with prior experience in gastric ESD but with no experience in colonic ESD each performed 30 ESD resections on standardized lesions in the rectosigmoid and left colon of the porcine simulator. Procedure time, en bloc resection status, and perforation were recorded., Results: All 90 lesions were resected using the ESD technique. The mean time of procedure was 49.6 min (standard deviation 29.6 min). The aggregate rate of perforation was 14.4% and the aggregate rate of non-en bloc resection was 5.6%. Using a composite quality score integrating complications and procedural time, it was found that there was a significant difference between two local polynomial regression lines when using a cut-point at the 9th procedure (p = 0.04), reflecting the point at which most of the learning curve is traversed., Conclusions: In this study, there were significant improvements realized in colonic ESD performance after 9 colon ESD procedures in ex vivo specimens. Although training will depend on endoscopist skill and expertise, we suggest at least 9 ex vivo procedures prior to moving to live animal or proctored training in colonic ESD.

Background: Peroral endoscopic pyloromyotomy is a novel technique that has recently been described in the literature. There is little data to guide the length of myotomy created. The aim of study was to evaluate the proper incision length of the muscular layer during peroral endoscopic pyloromyotomy using a submucosal tunnel technique., Methods: The study was designed as a prospective ex vivo study. Fresh ex vivo porcine stomachs from animals weighing 80-100 kg and porcine stomachs from animals weighing 15-25 kg were used for pyloromyotomy. Four different myotomy lengths (1, 2, 3, and 4) were compared in the large animal series and three different myotomy lengths (1, 2, and 3) were compared in the small series. A total of 23 cases of the submucosal tunnel technique were performed by two endoscopists using 12 large stomachs and 11 small stomachs., Results: The mean overall procedure time (± SD) of pyloromyotomy was 65.7 (± 14.3) min. In the large stomach series, the mean pyloric diameter (± SD) and change from baseline (as percentage) following a 1, 2, 3, and 4 pyloromyotomy were 13.3 ± 9.5 mm (7.1 %), 20.7 ± 11.7 mm (10.6 %), 31.1 ± 15.0 mm (15.2 %), and 33.0 ± 15.0 mm (16.0 %), respectively. In the small stomach series, the changes of mean pyloric diameter following a 1, 2, and 3 cm pyloromyotomy were 12.2 ± 5.6 mm (7.5 %), 23.1 ± 7.6 mm (13.1 %), and 28.0 ± 10.4 mm (15.5 %), respectively., Conclusions: A 3 cm pyloromyotomy for a large animal series and 2 cm for the small animal series appeared to be most appropriate for enlargement of the pylorus.

Background: It has been demonstrated that prolonged colonoscopic withdrawal times (WT; >6 min) are beneficial for the adenoma detection rate (ADR) for experienced endoscopists. There are little data, however, to guide the appropriate colonoscopic withdrawal times for trainees. The purpose of this study was to determine whether there is a relationship between WTs and ADR for first-year fellows training in colonoscopy., Methods: This is a prospective study of first-year gastroenterology fellows at a single academic teaching hospital who documented each colonoscopy with a self-report form over the course of an academic year (March 2010 to February 2011). The internal policy for the trainees was to have at least a 6-min withdrawal time for each colonoscopy., Results: Four first-year fellows in gastroenterology at an academic medical center completed self-reports for 1,210 colonoscopies. Mean WT was 10.2 ± 3.4 min. The aggregate polyp detection rate was 33.2% and the aggregate ADR was 22.3%. For colonoscopies with WT < 10 min, ADR was 9.5%, and for colonoscopies with WT ≥ 10 min, ADR was 32.3% (p < 0.001). When the quality indicator of 25% goal ADR for males and 15% goal ADR for females is applied, this aggregate rate is achieved for both sexes for screening colonoscopies (n = 676) with WT ≥ 10 min., Conclusions: First-year trainees had a significantly higher ADR if their colonoscopic WT is ≥ 10 min.

Background: Laparoscopic distal pancreatectomy is associated with high morbidity and mortality. NOTES tumor enucleation may provide an alternative to laparoscopic distal pancreatectomy. The goal of this study was to determine the feasibility of NOTES tumor creation and enucleation as a multidisciplinary approach., Methods: A linear-array endoscopic ultrasound (EUS) endoscope was used to inject a thermosensitive ABA triblock polymer mixed with methylene blue through the stomach wall and into the distal pancreas using a 22-gauge EUS needle. Due to its thermosensitive character, the polymer solidifies in response to body temperature, creating an artificial tumor. Seventeen swine underwent NOTES transgastric pancreatic tumor enucleation. Nine nonsurvival animals were sacrificed immediately after the NOTES procedure, with subsequent necropsy. Eight survival animals were observed for up to 16 days after the procedure, subsequently sacrificed, followed by necropsy., Results: The procedure was performed successfully in all 17 pigs studied, 9/9 nonsurvival (100%) and 8/8 survival (100%) animals, using a pure NOTES approach without any laparoscopic ports. Complications included two esophageal dissections (1 in nonsurvival group, 1 in survival group) caused by the introduction of the endoscopic overtube (2/17, 12%), unrelated to the actual surgical procedure. In the survival animals, there were two small splenic lacerations caused during retraction with the endoscopic forceps, for which hemostasis was achieved prior to closure of the gastrotomy (2/7, 29%). At necropsy of the animals, there was sufficient closure of 15/17 gastrotomy sites (88%)., Conclusions: The creation of artificial pancreatic tumors via EUS guidance is feasible. Pancreatic tumor enucleation using a transgastric NOTES approach is technically feasible and could be an alternative to laparoscopic distal pancreatectomy with further development. Further adoption and adaptation of this technique will require the development of more sophisticated specialized tools to improve the safety profile of the procedure.

Background: Morbid obesity accounts for more than 90,000 deaths per year in the United States. Laparoscopic adjustable gastric banding (LAGB) is the second most common weight loss procedure performed in the US and the most common in Europe and Australia. Simulation in surgical training is a rapidly advancing field that has been adopted by many to prepare surgeons for surgical techniques and procedures. The aim of our study was to determine face, construct, and content validity for a novel virtual reality laparoscopic adjustable gastric band simulator., Methods: Twenty-eight subjects were categorized into two groups (expert and novice), determined by their skill level in laparoscopic surgery. Experts consisted of subjects who had at least 4 years of laparoscopic training and operative experience. Novices consisted of subjects with medical training but with less than 4 years of laparoscopic training. The subjects used the virtual reality laparoscopic adjustable band surgery simulator. They were automatically scored according to various tasks. The subjects then completed a questionnaire to evaluate face and content validity., Results: On a 5-point Likert scale (1 = lowest score, 5 = highest score), the mean score for visual realism was 4.00 ± 0.67 and the mean score for realism of the interface and tool movements was 4.07 ± 0.77 (face validity). There were significant differences in the performances of the two subject groups (expert and novice) based on total scores (p < 0.001) (construct validity). Mean score for utility of the simulator, as addressed by the expert group, was 4.50 ± 0.71 (content validity)., Conclusion: We created a virtual reality laparoscopic adjustable gastric band simulator. Our initial results demonstrate excellent face, construct, and content validity findings. To our knowledge, this is the first virtual reality simulator with haptic feedback for training residents and surgeons in the laparoscopic adjustable gastric banding procedure.