Magnetic anchor guidance for endoscopic submucosal dissection and other endoscopic procedures

Endoscopic submucosal dissection(ESD) is a wellestablished, minimally invasive treatment for superficial neoplasms of the gastrointestinal tract. The universal adoption of ESD has been limited by its slow learning curve, long procedure times, and high risk of complications. One technical challenge is the lack of a second hand that can provide traction, as in conventional surgery. Reliable tissue retraction that exposes the submucosal plane of dissection would allow for safer and more efficient dissection. Magnetic anchor guided endoscopic submucosal dissection(MAGESD) has potential benefits compared to other current traction methods. MAG-ESD offers dynamic tissue retraction independent of the endoscope mimicking a surgeon's "second hand". Two types of magnets can be used: electromagnets and permanent magnets. In this article we review the MAG-ESD technology, published work and studies of magnets in ESD. We also review the use of magnetic anchor guidance systems in natural orifice transluminal endoscopic surgery and the idea of magnetic non-contact retraction using surface ferromagentization. We discuss the current limitations, the future potential of MAG-ESD and the developments needed for adoption of this technology.

Diagnostic and therapeutic direct peroral cholangioscopy using an intraductal anchoring balloon

AIM:To report our experience using a recently introduced anchoring balloon for diagnostic and therapeutic direct peroral cholangioscopy(DPOC).METHODS:Consecutive patients referred for diagnostic or therapeutic peroral cholangioscopy were evaluated in a prospective cohort study.The patients underwent DPOC using an intraductal anchoring balloon,which was recently introduced to allow consistent access to the biliary tree with an ultraslim upper endoscope.The device was later voluntarily withdrawn from the market by the manufacturer.RESULTS:Fourteen patients underwent DPOC using the anchoring balloon.Biliary access with an ultraslim upper endoscope was accomplished in all 14 patients.In 12(86%) patients,ductal access required sphincteroplasty with a 10-mm dilating balloon.Intraductal placement of the ultraslim upper endoscope allowed satisfactory visualization of the biliary mucosa to the level of the confluence of the right and left hepatic ducts in 13 of 14 patients(93%).Therapeutic interventions by DPOC were successfully completed in all five attempted cases(intraductal biopsy in one and DPOC guided laser lithotripsy in four).Adverse events occurred in a patient on immunosuppressive therapy who developed an intrahepatic biloma at the site of the anchoring balloon.This required hospitalization and antibiotics.Repeat endoscopic retrograde cholangiopancreatography 8 wk after the index procedure showed resolution of the biloma.CONCLUSION:Use of this anchoring balloon allowed consistent access to the biliary tree for performance of diagnostic and therapeutic DPOC distal to the biliary bifurcation.

Endoscopic ultrasound for the diagnosis of chronic pancreatitis

Endoscopic ultrasound(EUS) has become a well accepted test for the diagnosis of chronic pancreatitis.Advantages include its ability to detect subtle and severe changes of the pancreatic duct and parenchyma,and its relative safety compared with endoscopic retrograde cholangiopancreatography.Limitations include inter-and intraobserver variability,operator dependence,and an incomplete understanding of its true accuracy.The Rosemont classif ication has recently been proposed as a weighted,standardized method that may improve EUS chronic pancreatitis scoring.This paper reviews the published evidence regarding the accuracy of EUS in chronic pancreatitis diagnosis,and enumerates the emerging technologies that have been recently studied which may ultimately improve endosonographic imaging of the pancreas.

Update on endoscopic pancreatic function testing

Hormone-stimulated pancreatic function tests (PFTs) are considered the gold standard for measuring pancreatic exocrine function. PFTs involve the administration of intravenous secretin or cholecystokinin, followed by collection and analysis of pancreatic secretions. Because exocrine function may decline in the earliest phase of pancreatic fibrosis, PFTs are considered accurate for diagnosing chronic pancreatitis. Unfortunately, these potentially valuable tests are infrequently performed except at specialized centers, because they are time consuming and complicated. To overcome these limitations, endoscopic PFT methods have been developed which include aspiration of pancreatic secretions through the suction channel of the endoscope. The secretin endoscopic pancreatic function test (ePFT) involves collection of duodenal aspirates at 15, 30, 45 and 60 min after secretin stimulation. A bicarbonate concentration greater than 80 mmol/L in any of the samples is considered a normal result. The secretin ePFT has demonstrated good sensitivity and specificity compared with various reference standards, including the "Dreiling tube" secretin PFT, endoscopic ultrasound, and surgical histology. Furthermore, a standard autoanalyzer can be used for bicarbonate analysis, which allows the secretin ePFT to be performed at any hospital. The secretin ePFT may complement imaging tests like endoscopic ultrasound (EUS) in the diagnosis of early chronic pancreatitis.This paper will review the literature validating the use of ePFT in the diagnosis of exocrine insufficiency and chronic pancreatitis. Newer developments will also be discussed, including the feasibility of combined EUS/ ePFT, the use of cholecystokinin alone or in combination with secretin, and the discovery of new protein and lipid pancreatic juice biomarkers which may complement traditional fluid analysis.

Clinical outcomes of endoscopic management of pancreatic fluid collections in cirrhotics vs non-cirrhotics: A comparative study

BACKGROUND Endoscopic management of symptomatic pancreatic fluid collections (PFCs) using self-expandable metal stents (SEMS) placement has emerged as an innovative therapeutic approach with excellent efficacy, safety, and relatively few adverse outcomes. However, their use has not been studied in patients with cirrhosis. Cirrhotics tend to be considered less than optimal candidates due to concern for portal hypertension and coagulopathy related complications. AIM To compare the efficacy and safety of using SEMS for drainage of symptomatic PFCs in cirrhotic vs non-cirrhotic patients. METHODS We conducted a retrospective comparative analysis of patients with symptomatic PFCs [pancreatic pseudocyst (PP) or walled-off necrosis (WON)] who underwent endoscopic ultrasound (EUS)-guided placement of fully covered self-expandable metals stents or lumen-apposing self-expandable metal stents. All patients were followed clinically until resolution of PFCs or death. Definition:(1) Technical success was defined as successful placement of SEMS;and (2) Clinical success was defined as complete resolution of the PFCs without additional interventions including interventional radiology or surgery. Number of procedures performed per patient, number of patients who achieved complete resolution of the PFCs without additional interventions and procedure related adverse events were recorded.RESULTS From January 2012 to December 2017, a total of 88 patients underwent EUSguided drainage of symptomatic PFCs. Of these, 58 non cirrhotic patients underwent plastic stent insertion for management of PFC and 30 patients, 5 with cirrhosis and 25 without cirrhosis, underwent EUS-guided transmural drainage with SEMS, including 18 (60%) PP and 12 (40%) WON. Technical success was achieved in all 30 patients. Clinical success was achieved in 60% cirrhotic patients and 92% non-cirrhotics (P = 0.12). Procedure-related adverse events were 60% in cirrhotic and 28% non-cirrhotic (P = 0.62). Moreover, fatal adverse events were statistically more common in cirrhotics compared with non-cirrhotics (0 vs 40%;P = 0.023). Successful stent removal following resolution of the PFC, was 60% in cirrhotics and 80% in non-cirrhotics (P = 0.57). Post-procedure length of hospitalization was 18.6 ± 20.3 d in cirrhotics and 5.6 ± 13.7 d in non-cirrhotics (P = 0.084). CONCLUSION EUS-guided management of PFC using SEMS placement has a high technical and clinical success rate in non-cirrhotics. However, in cirrhotics caution must be exercised given the high morbidity and mortality as evidenced by our cohort, particularly for the endoscopic debridement of WONs. Larger, multicenter studies are warranted to further characterize the risk profile and outcomes in these patients.