Colonic-enteric lumen-apposing metal stents: a promising and safe alternative for endoscopic management of small-bowel obstruction.

BACKGROUND AND AIMS: Lumen-apposing metal stents (LAMSs) have revolutionized the treatment of various gastroenterologic conditions that previously required surgery. The use of LAMSs for the management of small-bowel obstruction (SBO) involves EUS-guided coloenterostomy (EUS-CE) between the colon and a dilated loop of the small intestine proximal to the point of obstruction. This procedure is potentially beneficial for patients with malignant SBO who are poor surgical candidates. METHODS: A retrospective cohort study was conducted at 2 tertiary care hospitals. Patients who underwent EUS-CE for SBO were identified, and data regarding patient demographics, indication for the procedure, location of the obstruction, procedural details, and adverse events were collected. The primary outcome was technical success of the procedure. Secondary outcomes were clinical success, resolution of symptoms, ability to tolerate enteral nutrition, and adverse events. RESULTS: Twenty-six patients who underwent the EUS-CE procedure were included. Technical success was achieved in all 26 patients, clinical success (resolution of obstructive symptoms) was achieved in 92.3% of patients (24/26), and the ability to resume enteral nutrition in 84.6% (22/26). Adverse events occurred in 4 patients (15.4%) and included bleeding (1/26), diarrhea (2/26), and postprocedure sepsis (1/26). Patients were followed for a mean of 54.8 days (range, 2-190). CONCLUSIONS: This study highlights that EUS-CE with LAMSs can be performed with high technical and clinical success for the management of SBO, particularly in patients with malignant obstructions who are not suitable candidates for surgical interventions. Further research with larger sample sizes will be essential to substantiate its efficacy and safety.

Curriculum for diagnostic endoscopic ultrasound training in Europe: European Society of Gastrointestinal Endoscopy (ESGE) Position Statement.

The European Society of Gastrointestinal Endoscopy (ESGE) has recognized the need to formalize and enhance training in diagnostic endoscopic ultrasound (EUS). This manuscript represents the outcome of a formal Delphi process resulting in an official Position Statement of the ESGE and provides a framework to develop and maintain skills in diagnostic EUS. This curriculum is set out in terms of the prerequisites prior to training; the recommended steps of training to a defined syllabus; the quality of training; and how competence should be defined and evidenced before independent practice. 1: Trainees should have achieved competence in upper gastrointestinal endoscopy before training in diagnostic EUS. 2: The development of diagnostic EUS skills by methods that do not involve patients is advisable, but not mandatory, prior to commencing formal training in diagnostic EUS. 3: A trainee's principal trainer should be performing adequate volumes of diagnostic EUSs to demonstrate maintenance of their own competence. 4: Training centers for diagnostic EUS should offer expertise, as well as a high volume of procedures per year, to ensure an optimal level of quality for training. Under these conditions, training centers should be able to provide trainees with a sufficient wealth of experience in diagnostic EUS for at least 12 months. 5: Trainees should engage in formal training and supplement this with a range of learning resources for diagnostic EUS, including EUS-guided fine-needle aspiration and biopsy (FNA/FNB). 6: EUS training should follow a structured syllabus to guide the learning program. 7: A minimum procedure volume should be offered to trainees during diagnostic EUS training to ensure that they have the opportunity to achieve competence in the technique. To evaluate competence in diagnostic EUS, trainees should have completed a minimum of 250 supervised EUS procedures: 80 for luminal tumors, 20 for subepithelial lesions, and 150 for pancreaticobiliary lesions. At least 75 EUS-FNA/FNBs should be performed, including mostly pancreaticobiliary lesions. 8: Competence assessment in diagnostic EUS should take into consideration not only technical skills, but also cognitive and integrative skills. A reliable valid assessment tool should be used regularly during diagnostic EUS training to track the acquisition of competence and to support trainee feedback. 9: A period of supervised practice should follow the start of independent activity. Supervision can be delivered either on site if other colleagues are already practicing EUS or by maintaining contacts with the training center and/or other EUS experts. 10: Key performance measures including the annual number of procedures, frequency of obtaining a diagnostic sample during EUS-FNA/FNB, and adverse events should be recorded within an electronic documentation system and evaluated.

Ablation Therapy of the Biliary Tree: Status and Comprehensive Review.

Malignant biliary obstruction is typically referred to endoscopists for palliation. A curative resection is indeed rarely an option in this condition. Photodynamic therapy and radiofrequency ablation are 2 modalities that can be offered in those patients. Many studies have demonstrated improved stent patency and survival after ablation. Photodynamic therapy is unfortunately very expensive and is associated with photosensitivity; however, it transmits to the entire biliary tree. Radiofrequency ablation is more affordable and easier to apply but requires contact with the tumor to be efficient. This review explores both modalities in terms of their safety and efficacy for bile duct cancer palliation.

Impact of COVID-19 Infection on Pancreato-Biliary Diseases Requiring Endoscopic Retrograde Cholangiopancreatography.

BACKGROUND: Viral infections are known to impact the pancreato-biliary system; however, there are limited data showing that the same is true of COVID-19. Endoscopic retrograde cholangiopancreatography (ERCP) can safely be performed in patients with COVID-19 infection, but outcomes of patients with COVID-19 infections and concomitant pancreatic and biliary disease requiring endoscopic intervention are unknown. AIMS: This study aims to evaluate the severity of pancreaticobiliary diseases and post-ERCP outcomes in COVID-19 patients. METHODS: Patients with pancreato-biliary disease that required inpatient ERCP from five centers in the United States and South America between January 1, 2020, and October 31, 2020 were included. A representative cohort of patients from each month were randomly selected from each site. Disease severity and post-ERCP outcomes were compared between COVID-19 positive and COVID-19 negative patients. RESULTS: A total of 175 patients were included: 95 COVID positive and 80 COVID negative. Mean CTSI score for the patients who had pancreatitis was higher in COVID-positive cohort by 3.2 points (p < .00001). The COVID-positive group had more cases with severe disease (n = 41) versus the COVID-negative group (n = 2) (p < .00001). Mortality was higher in the COVID-19 positive group (19%) compared to COVID-negative group (7.5%) even though the COVID-19-negative group had higher incidence of malignancy (n = 17, 21% vs n = 7, 7.3%) (p = 0.0455). CONCLUSIONS: This study shows that patients with COVID infection have more severe pancreato-biliary disease and worse post-ERCP outcomes, including longer length of stay and higher mortality rate. These are important considerations when planning for endoscopic intervention. CLINICALTRIALS: gov: (NCT05051358).

The outcomes and safety of patients undergoing endoscopic retrograde cholangiopancreatography combining a single-use cholangioscope and a single-use duodenoscope: A multicenter retrospective international study.

BACKGROUND: Duodenoscope-related multidrug-resistant organism (MDRO) infections raise concerns. Disposable duodenoscopes have been recently introduced in the market and approved by regulatory agencies with the aim to reduce the risk of endoscopic retrograde cholangiopancreatography (ERCP) associated infections. The aim of this study was to evaluate the outcome of procedures performed with single-use duodenoscopes in patients with clinical indications to single-operator cholangiopancreatoscopy. METHODS: This is a multicenter international, retrospective study combining all patients who underwent complex biliopancreatic interventions using the combination of a single-use duodenoscope and a single-use cholangioscope. The primary outcome was technical success defined as ERCP completion for the intended clinical indication. Secondary outcomes were procedural duration, rate of cross-over to reusable duodenoscope, operator-reported satisfaction score (1 to 10) on performance rating of the single-use duodenoscope, and adverse event (AE) rate. RESULTS: A total of 66 patients (26, 39.4% female) were included in the study. ERCP was categorized according to ASGE ERCP grading system as 47 (71.2%) grade 3 and 19 (28.8%) grade 4. The technical success rate was 98.5% (65/66). Procedural duration was 64 (interquartile range 15-189) min, cross-over rate to reusable duodenoscope was 1/66 (1.5%). The satisfaction score of the single-use duodenoscope classified by the operators was 8.6 ± 1.3 points. Four patients (6.1%) experienced AEs not directly related to the single-use duodenoscope, namely 2 post-ERCP pancreatitis (PEP), 1 cholangitis and 1 bleeding. CONCLUSIONS: Single-use duodenoscope is effective, reliable and safe even in technically challenging procedures with a non-inferiority to reusable duodenoscope, making these devices a viable alternative to standard reusable equipment.

Artificial intelligence for diagnosing neoplasia on digital cholangioscopy: development and multicenter validation of a convolutional neural network model.

BACKGROUND: We aimed to develop a convolutional neural network (CNN) model for detecting neoplastic lesions during real-time digital single-operator cholangioscopy (DSOC) and to clinically validate the model through comparisons with DSOC expert and nonexpert endoscopists. METHODS: In this two-stage study, we first developed and validated CNN1. Then, we performed a multicenter diagnostic trial to compare four DSOC experts and nonexperts against an improved model (CNN2). Lesions were classified into neoplastic and non-neoplastic in accordance with Carlos Robles-Medranda (CRM) and Mendoza disaggregated criteria. The final diagnosis of neoplasia was based on histopathology and 12-month follow-up outcomes. RESULTS: In stage I, CNN2 achieved a mean average precision of 0.88, an intersection over the union value of 83.24 %, and a total loss of 0.0975. For clinical validation, a total of 170 videos from newly included patients were analyzed with the CNN2. Half of cases (50 %) had neoplastic lesions. This model achieved significant accuracy values for neoplastic diagnosis, with a 90.5 % sensitivity, 68.2 % specificity, and 74.0 % and 87.8 % positive and negative predictive values, respectively. The CNN2 model outperformed nonexpert #2 (area under the receiver operating characteristic curve [AUC]-CRM 0.657 vs. AUC-CNN2 0.794, P < 0.05; AUC-Mendoza 0.582 vs. AUC-CNN2 0.794, P < 0.05), nonexpert #4 (AUC-CRM 0.683 vs. AUC-CNN2 0.791, P < 0.05), and expert #4 (AUC-CRM 0.755 vs. AUC-CNN2 0.848, P < 0.05; AUC-Mendoza 0.753 vs. AUC-CNN2 0.848, P < 0.05). CONCLUSIONS: The proposed CNN model distinguished neoplastic bile duct lesions with good accuracy and outperformed two nonexpert and one expert endoscopist.

Drainage Approach for Malignant Biliary Obstruction: A Changing Paradigm.

Endoscopic retrograde cholangiopancreatography (ERCP) is the standard of care in the management of unresectable malignant biliary obstruction. However, endoscopic ultrasound (EUS)-guided biliary drainage has become widely accepted over the past several years for complicated biliary drainage in cases when ERCP is unsuccessful or not feasible. Recent emerging evidence suggests EUS-guided hepaticogastrostomy and EUS-guided choledochoduodenostomy are noninferior, and possibly even superior to conventional ERCP for primary palliation of malignant biliary obstruction. This article reviews the procedural techniques and considerations of the different techniques as well as comparative literature on safety and efficacy between techniques.

Management of Pancreatic Fluid Collections: An Evidence-based Approach.

Managing pancreatic fluid collections (PFCs) remains a challenge for many clinicians. Recently, significant progress has been made in the therapy of PFCs, including improvements in technology and devices, as well as in the development of minimally invasive endoscopic techniques, many of which are proven less traumatic when compared with surgical options and more efficacious when compared with percutaneous techniques. This review will explore latest developments in the management of PFCs and how they incorporate into the current treatment algorithm.

Endoscopic Submucosal Dissection (ESD) Offers a Safer and More Cost-effective Alternative to Transanal Endoscopic Microsurgery (TEM): An International Collaborative Study.

BACKGROUND: Endoscopic submucosal dissection (ESD) and transanal endoscopic microsurgery (TEM) are minimally invasive procedures that treat early rectal cancer (ERC). Both are effective treatments, yet there are very few studies comparing them. The aim of our study was to identify ideal candidates for each procedure. MATERIALS AND METHODS: Between January 2016 and November 2019, 204 ERC patients were managed with either ESD (n=101) or TEM (n=103) at 7 international centers. Data analyzed included clinical success, tumor characteristics, procedure info, and recurrence rates. RESULTS: Median tumor size was 40 mm±23.9 in the ESD group and 56 mm±27.9 in the TEM group, significantly larger in the latter ( P <0.00001). Average procedure time was 131.5±67.9 minutes in ESD group and 104.9±28.4 minutes in TEM group ( P =0.000347). Average hospital stay was 3.3±2.6 days in the ESD group and 4.7±0.7 days in the TEM group ( P <0.00001). Adverse event rate was 6.8% in the ESD group and 24% in the TEM group. There were no significant difference in the rate of en bloc resection, technical success, tumor location, necessity of additional procedures, and tumor recurrence rates. CONCLUSION: Compared with TEM, ESD is a safer procedure with shorter hospital stay and should be offered for patients who have ERC.

EUS-Guided Biliary Drainage Versus ERCP in Malignant Biliary Obstruction Before Hepatobiliary Surgery: An International Multicenter Comparative Study.

INTRODUCTION: Endoscopic ultrasound-guided biliary drainage (EUS-BD) is the procedure of choice for patients who cannot undergo endoscopic retrograde cholangiopancreatography (ERCP). The outcomes of patients undergoing surgery after EUS-BD for malignancy are unknown. METHODS: We conducted an international, multicenter retrospective comparative study of patients who underwent hepatobiliary surgery after having undergone EUS-BD or ERCP from 6 tertiary care centers. Patient demographics, procedural data, and follow-up care were collected in a registry. RESULTS: One hundred forty-five patients were included: EUS-BD n=58 (mean age 66, 45% male), ERCP n=87 (mean age 68, 53% male). The majority of patients had pancreatic cancer, cholangiocarcinoma, or gallbladder malignancy. In the EUS-BD group, 29 patients had hepaticogastrostomy, 24 had choledochoduodenostomy, and 5 had rendezvous technique done. The most common surgery was Whipple in both groups (n=41 EUS-BD, n=56 ERCP) followed by partial hepatectomy (n=7 EUS-BD, n=14 ERCP) and cholecystectomy (n=2 EUS-BD, n=2 ERCP). Endoscopy clinical success was comparable in both groups (98% EUS-BD, 94% ERCP). Adverse event rates were similar in both groups: EUS-BD (n=10, 17%) and ERCP (n=23, 26%). Surgery technical success and clinical success were significantly higher in the EUS-BD group compared with the ERCP group (97% vs. 83%, 97% vs. 75%). Total Hospital stay from surgery to discharge was significantly higher in the ERCP group (19 d vs. 10 d, P =0.0082). DISCUSSION: Undergoing EUS-BD versus ERCP before hepatobiliary surgery is associated with fewer repeat endoscopic interventions, shorter duration between endoscopy and surgical intervention, higher rates of surgical clinical success, and shorter length of hospital stay after surgery.

EUS-guided Gastroenterostomy: A Multicenter International Study Comparing Benign and Malignant Diseases.

BACKGROUND: Endoscopic ultrasound (EUS)-guided gastroenterostomy (EUS-GE) is a minimally invasive therapy for patients with gastric outlet obstruction without the risks of surgical bypass and the limited long-term efficacy of enteral self-expanding metal stent placement. However, due to its novelty, there is a lack of significant data comparing long-term outcomes of patients with EUS-GE, based on the underlying disease. In this study, we compare outcomes of EUS-GE on benign versus malignant indications. METHODS: Consecutive patients from 12 international, tertiary care centers who underwent EUS-GE over 3 years were extracted in a retrospective registry. Demographic characteristics, procedure-related information and follow-up data was collected. Primary outcome was the rate of adverse events associated with EUS-GE and the comparison of the rate of adverse events in benign versus malignant diseases. Secondary outcomes included technical and clinical success as well as hospitalization admission. RESULTS: A total of 103 patients were included: 72 malignant and 31 benign. The characteristics of the patients undergoing EUS-GE is shown in Table 1. The mean age of the cohort was 68 years and 58 years for malignant and benign etiology. Gender distribution was 57% and 39% being females in malignant and benign etiology group, respectively. Clinical success, technical success, average procedure time, and hospital length of stay were similar in both groups. Patients with benign underlying etiology had significantly higher number of surgically altered midgut anatomy (P=0.0379). CONCLUSION: EUS-GE is equally efficient regardless of the underlying etiology (malignant vs. benign), and the adverse events both groups were comparable.

Comparing the Safety and Efficacy of Two Commercially Available Single-Use Duodenoscopes: A Multicenter Study.

INTRODUCTION: Single-use disposable duodenoscopes (SDD) have been developed to mitigate infectious risks related to reusable duodenoscopes. The aim of this study is to compare the safety and efficacy of the two available SDDs in the United States. METHODS: We conducted a comparative study of 2 SDD in consecutive ERCP procedures performed by expert endoscopists from 9 academic centers. Performance ratings, procedure details, and adverse events were collected. RESULTS: A total of 201 patients were included: 129 patients underwent ERCP with Exalt (mean age 63, Males- 66 (51%), 72 with aScope Duodeno (mean age 65, males=30 (42%). A majority of endoscopists had performed >2000 ERCPs in both groups (71% Exalt, 93% aScope Duodeno). Technical success was 92% in both groups (n=119 Exalt-group, n=66 aScope-Duodeno-group). The procedural complexity for the ERCP cases performed were: Grade 1: 35 cases (18%), Grade 2: 83 cases (41%), Grade 3: 65 cases (32%), and Grade 4: 18 cases (9%). Thirteen patients (10%) from the Exalt group and 16 patients (22%) from the aScope Duodeno group required conversion to a reusable duodenoscope. On a scale of 1 to 5, Exalt and aScope Duodeno, respectively, were rated: 2.31 versus 2.60 for location and visualization quality, 1.38 versus 1.57 for maneuverability based on papillary orientation, 1.48 versus 1.15 for suction/air control, and 2.31 versus 2.34 for elevator efficiency. None of the adverse events were related to the SDDs. CONCLUSIONS: The 2 SDDs were comparable. Further ongoing enhancements to these devices will improve maneuverability and clinical effectiveness.

Endoscopic Ultrasound-Directed Transgastric ERCP (EDGE) Utilization of Trends Among Interventional Endoscopists.

BACKGROUND: Endoscopic ultrasound-directed transgastric ERCP (EDGE) has become standard-of-care therapy at many centers for pancreaticobiliary disease in patients with Roux-en-Y Gastric Bypass. In this study, we aimed to evaluate the opinions and practices of endoscopists who perform EDGE. METHODS: A 22-question utilization of EDGE survey was sent to 36 advanced endoscopists at tertiary care centers in the United States. The two-section survey included questions regarding advanced endoscopy volume and training at the respective facilities, and questions on specific details of EDGE utilization. RESULTS: Among 36 interventional endoscopists (IE) surveyed, 14 (39%) reported performing > 1000 ERCPs annually. Thirty (83%) offered EDGE as an option for Roux-en-Y gastric bypass patients with previous cholecystectomy. Other options offered included: 19 (53%) offered Laparoscopy-assisted ERCP (LA-ERCP), 7 (19%) offered Single-Balloon ERCP (SBE), and 10 (28%) offered percutaneous drainage (PTC). Twenty (56%) IE performed 10 or less EDGE procedures, while 16 (44%) performed 11 or more. Single-session EDGE was performed by 7 (19%) IE, while 15 (42%) performed dual session, and 13 (36%) performed both. 19 (53%) actively closed fistulas while 17 (47%) let them close spontaneously. Thirty one (86%) reported a technical success rate of 91% to 100%. The most frequently reported immediate adverse event post-procedurally was abdominal pain, reported by 17 IE (47%). Weight gain was reported by 2 IE (6%). CONCLUSION: EDGE continues to gain in popularity as an option for Roux-en-Y gastric bypass patients requiring pancreaticobiliary interventions, with 24/36 IE (67%) believing that it should be the new standard. In addition, most report a low frequency of post-procedural weight gain. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT05041608.

Endoscopic management of benign and malignant hilar stricture.

Management of hilar strictures pose a significant challenge for endoscopists. Several strategies have been demonstrated in the last decade beyond decompression, however, there remains controversy and minimal consensus in the literature. This review seeks to summarize the current literature and discuss emerging therapies, such as photodynamic therapy and radiofrequency ablation.

Per-oral pancreatoscopy-guided lithotripsy vs. extracorporeal shock wave lithotripsy for treating refractory main pancreatic duct stones in chronic pancreatitis: Protocol for an open-label multi-center randomized clinical trial.

BACKGROUNDS/OBJECTIVES: Patients with chronic pancreatitis may develop pancreatic duct stones that can obstruct outflow leading to ductal hypertension and pain. Both endoscopic retrograde pancreatography (ERP) with per-oral pancreatoscopy (POP) and intraductal lithotripsy and extracorporeal shock wave lithotripsy (ESWL) are feasible options to attempt ductal stone clearance. This study aims to compare POP-guided lithotripsy with ESWL in the management of refractory symptomatic main pancreatic duct stones. METHODS: This is an open-label, multi-center, parallel, randomized clinical trial. Patients with chronic pancreatitis and main pancreatic duct stones ≥5 mm who fail standard ERP methods for stone removal will be eligible for this study. In total, 150 subjects will be randomized 1:1 to either ESWL or POP. A maximum of 4 sessions of either ESWL or POP will be allowed in each arm, with crossover permitted thereafter. The primary outcome is complete stone clearance and secondary outcomes include quality of life, pain scores, number of interventions, and daily opiate requirements. CONCLUSIONS: This study aims to answer the question of which lithotripsy method is superior in removing refractory pancreatic duct stones while addressing the effects of lithotripsy on quality of life and pain in patients with chronic calcific pancreatitis (ClinicalTrials.gov NCT04115826).

Digital single-operator cholangioscopy interobserver study using a new classification: the Mendoza Classification (with video).

BACKGROUND AND AIMS: Digital single-operator cholangioscopy (DSOC) allows direct visualization of the biliary tree for evaluation of biliary strictures. Our objective was to assess the interobserver agreement (IOA) of DSOC interpretation for indeterminate biliary strictures using newly refined criteria. METHODS: Fourteen endoscopists were asked to review an atlas of reference clips and images of 5 criteria derived from expert consensus. They then proceeded to score 50 deidentified DSOC video clips based on the visualization of tortuous and dilated vessels, irregular nodulations, raised intraductal lesions, irregular surface with or without ulcerations, and friability. The endoscopists then diagnosed the clips as neoplastic or non-neoplastic. Intraclass correlation (ICC) analysis was done to evaluate inter-rater agreement for both criteria sets and final diagnosis. RESULTS: Clips of 41 malignant lesions and 9 benign lesions were scored. Three of 5 revised criteria had almost perfect agreement. ICC was almost perfect for presence of tortuous and dilated vessels (.86), raised intraductal lesions (.90), and presence of friability (.83); substantial agreement for presence of irregular nodulations (.71); and moderate agreement for presence of irregular surface with or without ulcerations (.44). The diagnostic ICC was almost perfect for neoplastic (.90) and non-neoplastic (.90) diagnoses. The overall diagnostic accuracy using the revised criteria was 77%, ranging from 64% to 88%. CONCLUSIONS: The IOA and accuracy rate of DSOC using the new Mendoza criteria shows a significant increase of 16% and 20% compared with previous criteria. The reference atlas helps with formal training and may improve diagnostic accuracy. (Clinical trial registration number: NCT02166099.).

Safety and efficacy of a novel resection system for direct endoscopic necrosectomy of walled-off pancreas necrosis: a prospective, international, multicenter trial.

BACKGROUND AND AIMS: Direct endoscopic necrosectomy (DEN) of walled-off pancreatic necrosis (WOPN) lacks dedicated instruments and requires repetitive and cumbersome procedures. This study evaluated the safety and efficacy of a new powered endoscopic debridement (PED) system designed to simultaneously resect and remove solid debris within WOPN. METHODS: This was a single-arm, prospective, multicenter, international device trial conducted from November 2018 to August 2019 at 10 sites. Patients with WOPN ≥6 cm and ≤22 cm and with >30% solid debris were enrolled. The primary endpoint was safety through 21 days after the last DEN procedure. Efficacy outcomes included clearance of necrosis, procedural time, adequacy of debridement, number of procedures until resolution, hospital stay duration, and quality of life. RESULTS: Thirty patients (mean age, 55 years; 60% men) underwent DEN with no device-related adverse events. Of 30 patients, 15 (50%) achieved complete debridement in 1 session and 20 (67%) achieved complete debridement within 2 or fewer sessions. A median of 1.5 interventions (range, 1-7) were required. Median hospital stay was 10 days (interquartile range, 22). There was an overall reduction of 91% in percent necrosis within WOPN from baseline to follow-up and 85% in collection volume. Baseline WOPN volume was positively correlated with the total number of interventions (ρ = .363, P = .049). CONCLUSIONS: The new PED system seems to be a safe and effective treatment tool for WOPN, resulting in fewer interventions and lower hospital duration when compared with published data on using conventional instruments. Randomized controlled trials comparing the PED system with conventional DEN are needed. (Clinical trial registration number: NCT03694210.).

New Applications for Submucosal Tunneling in Third Space Endoscopy: A Comprehensive Review.

Third space endoscopy (TSE), a type of natural orifice transluminal endoscopic surgery, was first introduced a decade ago, and since then, has revolutionized the field of therapeutic endoscopy. TSE involves tunneling into the submucosal space between the intestinal mucosa and the muscularis propria. By accessing this "third space," endoscopists can perform minimally invasive myotomies, resections, and dissections while maintaining the mucosa and preventing full-thickness perforation. TSE procedures can be used to treat motility disorders as well as neoplasms throughout the gastrointestinal tract, which were traditionally conditions that would require open or laparoscopic surgery. The main TSE procedures include peroral endoscopic myotomy, gastric peroral endoscopic myotomy, Zenker peroral endoscopic myotomy, submucosal tunneling for endoscopic resection, endoscopic submucosal tunnel dissection, peroral endoscopic tunneling for restoration of the esophagus, and per-rectal endoscopic myotomy. Some of those procedures have now been accepted as viable alternative to surgical techniques due to their limited invasiveness, safety and cost. This review will explore the different techniques recently added to our arsenal while describing their potential efficacy and limitations.

Per-oral Endoscopic Myotomy: State of the Art.

For more than a decade, per-oral endoscopic myotomy (POEM) has been performed for the treatment of achalasia and other dysmotilities of the esophagus. POEM has become an accepted alternative to Heller myotomy, a salvation technique for patients not responding to Heller myotomy and the favorite intervention for diffuse esophageal spasm and jackhammer esophagus. POEM paved the way for endoscopic pyloromyotomy, Zenker's diverticulum myotomy, and submucosal tunneling with endoscopic resection. This review will cover the technique and the most current literature of this revolutionary third space technique.

Endoscopic Treatment of Reflux: A Comprehensive Review.

The last decade has seen the rise of multiple novel endoscopic techniques to treat gastroesophageal reflux disease, many of which are efficacious when compared with traditional surgical options and allow relief from long-term dependence on antacid medications. This review will explore the latest endoscopic treatment options for gastroesophageal reflux disease including a description of the technique, review of efficacy and safety, and future directions.