Endoscopic management of malignant biliary obstructions.

Malignant biliary obstruction (MBO), both distal and hilar, represents an ensemble of different clinical conditions frequently encountered in everyday practice. Given the frequent unresectability of the disease at presentation and the increasing indications for neoadjuvant chemotherapy, endoscopic biliary drainage is generally required during the course of the disease. With the widespread use of interventional endoscopic ultrasound (EUS) and the introduction of dedicated devices, EUS-guided biliary drainage has rapidly gained acceptance, together with transpapillary endoscopic biliary drainage and the percutaneous approach. This comprehensive review describes the current role of endoscopy for distal and hilar MBO supported by evidence, with a focus on the current hot topics in this field.

Endoscopic Ultrasound-Guided Drainage of Pancreatic Fluid Collections: Not All Queries Are Already Solved.

Pancreatic fluid collections (PFCs) are well-known complications of acute pancreatitis. The overinfection of these collections leads to a worsening of the prognosis with an increase in the morbidity and mortality rate. The primary strategy for managing infected pancreatic necrosis (IPN) or symptomatic PFCs is a minimally invasive step-up approach, with endosonography-guided (EUS-guided) transmural drainage and debridement as the preferred and less invasive method. Different stents are available to drain PFCs: self-expandable metal stents (SEMSs), double pigtail stents (DPPSs), or lumen-apposing metal stents (LAMSs). In particular, LAMSs are useful when direct endoscopic necrosectomy is needed, as they allow easy access to the necrotic cavity; however, the rate of adverse events is not negligible, and to date, the superiority over DPPSs is still debated. Moreover, the timing for necrosectomy, the drainage technique, and the concurrent medical management are still debated. In this review, we focus attention on indications, timing, techniques, complications, and particularly on aspects that remain under debate concerning the EUS-guided drainage of PFCs.

Metal stent and percutaneous endoscopic necrosectomy as dual approach for the management of complex walled-off pancreatic necrosis.

Pancreatic fluid collections (PFCs) are one of the local complications of acute pancreatitis and include walled-off pancreatic necrosis (WOPN), which are complex entities with challenging management. The infection of pancreatic necrosis leads to a poorer prognosis, with a growth of the mortality rate up to 30%. The primary strategy for managing PFCs is a minimally invasive step-up approach, with endosonography-guided transmural drainage and debridement as the preferred and less invasive method. Percutaneous drainage (PCD) can be the technique of choice when endoscopic drainage is not feasible, for example for early PFCs without a mature wall or for the anatomic location and extension to the paracolic gutter of the collection. As PCD alone may be ineffective, especially when a great amount of necrosis is present, a percutaneous endoscopic necrosectomy (PEN) has been proposed, showing interesting results. The technique consists of the placement of an esophageal fully or partially covered self-expandable metal stent (SEMS) percutaneously into the collection and a direct debridement can be performed using a flexible endoscope through the SEMS. In this review, we will discuss about the role of metal stent and PEN for the management of complex walled-off pancreatic necrosis.

Endoscopic Management of Bleeding in Altered Anatomy after Upper Gastrointestinal Surgery.

Postoperative non variceal upper gastrointestinal haemorrhage may occur early or late and affect a variable percentage of patients-up to about 2%. Most cases of intraluminal bleeding are an indication for urgent Esophagogastroduodenoscopy (EGD) and require endoscopic haemostatic treatment. In addition to the approach usually adopted in non-variceal upper haemorrhages, these cases may be burdened with difficulties in terms of anastomotic tissue, angled positions, and the risk of further complications. There is also extreme variability related to the type of surgery performed, in the context of oncological disease or bariatric surgery. At the same time, the world of haemostatic devices available in digestive endoscopy is increasing, meeting high efficacy rates and attempting to treat even the most complex cases. Our narrative review summarises the current evidence in terms of different approaches to endoscopic haemostasis in upper bleeding in altered anatomy after surgery, proposing an up-to-date guidance for endoscopic clinicians and at the same time, highlighting areas of future scientific research.

Direct Endoscopic Necrosectomy of a Recurrent Walled-Off Pancreatic Necrosis at High Risk for Severe Bleeding: A Hybrid Technique Using a Dedicated Device.

Direct endoscopic necrosectomy (DEN) is a challenging procedure for the debridement of walled-off pancreatic necrosis (WOPN), which may be complicated by several adverse events, primarily bleeding which may require radiological embolization or even surgery. The lack of dedicated devices for this purpose largely affects the possibility of safely performing DEN which increases the risk of complications. We present the case of a 63 years-old man who underwent an endoscopic ultrasound (EUS)-guided drainage of a WOPN, and who was readmitted one month after stent removal with clinical, endoscopic, and radiological signs of infected necrosis involving the splenic artery. A second EUS-guided drainage was performed, with clear visualization of the arterial vessel in the midst of a large amount of solid necrosis. Due to the high risk of major bleeding during DEN, a hybrid procedure in the angiographic room was performed, in order to identify and avoid, under fluoroscopic control, the splenic artery during the entire procedure guide, which was successfully performed using the EndoRotor system. We hereby review the current literature regarding DEN using the EndoRotor system. The case reported, with a literature overview, may help the management of these patients affected by benign but life-threatening conditions which involve a multidisciplinary setting.

Usefulness of Contrast-Enhanced Endoscopic Ultrasound (CH-EUS) to Guide the Treatment Choice in Superficial Rectal Lesions: A Case Series.

INTRODUCTION: Large rectal lesions can conceal submucosal invasion and cancer nodules. Despite the increasing diffusion of high-definition endoscopes and the importance of an accurate morphological evaluation, a complete assessment in this setting can be challenging. Endoscopic ultrasound (EUS) plays an established role in the locoregional staging of rectal cancer, although this technique has a tendency toward the over-estimation of the loco-regional (T) staging. However, there are still few data on contrast-enhanced endoscopic ultrasound (CH-EUS), especially if this ancillary technique may increase the accuracy for predicting invasive nodules among large rectal lesions. MATERIAL AND METHODS: Consecutive large (≥20 mm) superficial rectal lesions with high-definition endoscopy, characterized by focal areas suggestive for invasive cancer/2B type according to JNET classification, were considered for additional standardized evaluation via CH-EUS with Sonovue ©. RESULTS: From 2020 to 2023, we evaluated 12 consecutive superficial rectal lesions with sizes ranging from 20 to 180 mm. This evaluation provided additional elements to support the therapeutic decision made. Lesions were treated with surgical (3/12) or endoscopic treatment (9/12) according to their morphology and CH-EUS evaluation. CONCLUSION: Contrast-enhanced endoscopic ultrasound can provide an additional evaluation for large and difficult-to-classify rectal lesions. In our experience, CH-EUS staging corresponded to the final pathological stages in 9/12 (75%) lesions, improving the distinction between T1 and T2 lesions. Larger prospective studies and randomized trials should be conducted to support and standardize this approach.

The Use of PuraStat® in the Management of Walled-Off Pancreatic Necrosis Drained Using Lumen-Apposing Metal Stents: A Case Series.

Background and Objectives: Bleeding is one of the most feared and frequent adverse events in the case of EUS-guided drainage of WOPN using lumen-apposing metal stents (LAMSs) and of direct endoscopic necrosectomy (DEN). When it occurs, its management is still controversial. In the last few years, PuraStat, a novel hemostatic peptide gel has been introduced, expanding the toolbox of the endoscopic hemostatic agents. The aim of this case series was to evaluate the safety and efficacy of PuraStat in preventing and controlling bleeding of WOPN drainage using LAMSs. Materials and Methods: This is a multicenter, retrospective pilot study from three high-volume centers in Italy, including all consecutive patients treated with the novel hemostatic peptide gel after LAMSs placement for the drainage of symptomatic WOPN between 2019 and 2022. Results: A total of 10 patients were included. All patients underwent at least one session of DEN. Technical success of PuraStat was achieved in 100% of patients. In seven cases PuraStat was placed for post-DEN bleeding prevention, with one patient experiencing bleeding after DEN. In three cases, on the other hand, PuraStat was placed to manage active bleeding: two cases of oozing were successfully controlled with gel application, and a massive spurting from a retroperitoneal vessel required subsequent angiography. No re-bleeding occurred. No PuraStat-related adverse events were reported. Conclusions: This novel peptide gel could represent a promising hemostatic device, both in preventing and managing active bleeding after EUS-guided drainage of WON. Further prospective studies are needed to confirm its efficacy.

Endoscopic Management of Postoperative Esophageal and Upper GI Defects-A Narrative Review.

Anastomotic defects are deleterious complications after either oncologic or bariatric surgery, leading to high morbidity and mortality. Besides surgical revision in early stages or instable patients, endoscopic treatment has become the mainstay. To date, many options for endoscopic treatment in this setting exist, including fully covered metal stent placement, endoscopic vacuum therapy (EVT), endoscopic internal drainage with pigtail placement (EID), leak closure with through the scope or over the scope clips, endoluminal suturing, fibrin glue sealing and a combination of all these techniques. Current evidence is mostly based on retrospective single and multicenter studies. No guidelines exist in this important field. Treatment options have to be chosen upon each case individually, taking into account clinical and anatomic criteria, such as timing, size, infectious wound complications and hemodynamic stability. Local expertise and availability of treatment devices need to be taken into account whenever choosing a treatment strategy. This review aimed to present current treatment options in terms of effectiveness, advantages and disadvantages in order to guide the clinician for his decision making. Additionally, we aimed to provide a treatment algorithm.

Recent developments in small bowel endoscopy: the "black box" is now open!

Over the last few years, capsule endoscopy has been established as a fundamental device in the practicing gastroenterologist's toolbox. Its utilization in diagnostic algorithms for suspected small bowel bleeding, Crohn's disease, and small bowel tumors has been approved by several guidelines. The advent of double-balloon enteroscopy has significantly increased the therapeutic possibilities and release of multiple devices (single-balloon enteroscopy and spiral enteroscopy) aimed at improving the performance of small bowel enteroscopy. Recently, some important innovations have appeared in the small bowel endoscopy scene, providing further improvement to its evolution. Artificial intelligence in capsule endoscopy should increase diagnostic accuracy and reading efficiency, and the introduction of motorized spiral enteroscopy into clinical practice could also improve the therapeutic yield. This review focuses on the most recent studies on artificial-intelligence-assisted capsule endoscopy and motorized spiral enteroscopy.

Traces of a prehistoric and potentially tsunamigenic mass movement in the sediments of Lake Thun (Switzerland).

Mass movements constitute major natural hazards in the Alpine realm. When triggered on slopes adjacent to lakes, these mass movements can generate tsunami-like waves that may cause additional damage along the shore. For hazard assessment, knowledge about the occurrence, the trigger and the geomechanical and hydrogeological mechanisms of these mass movements is necessary. For reconstructing mass movements that occurred in or adjacent to lakes, the lakes's sedimentary record can be used as an archive. Here, we present a prehistorical mass-movement event, of which the traces were found in an alpine lake, Lake Thun, in central Switzerland. The mass movement is identified by large blocks on the bathymetric map, a chaotic to transparent facies on the reflection seismic profiles, and by a mixture of deformed lake sediments and sandy organic-rich layers in the sediment-core record. The event is dated at 2642-2407 cal year BP. With an estimated volume of ~ 20 × 106 m3 it might have generated a wave with an initial amplitude of > 30 m. In addition to this prehistorical event, two younger deposits were identified in the sedimentary record. One could be dated at 1523-1361 cal year BP and thus can be potentially related to an event in 598/599 AD documented in historical reports. The youngest deposit is dated at 304-151 cal year BP (1646-1799 AD) and is interpreted to be related to the artificial Kander river deviation into Lake Thun (1714 AD). Supplementary Information: The online version contains supplementary material available at 10.1186/s00015-022-00405-0.

A Robust Workflow for Acquiring and Preprocessing Ambient Vibration Data from Small Aperture Ocean Bottom Seismometer Arrays to Extract Scholte and Love Waves Phase-Velocity Dispersion Curves.

The phase-velocity dispersion curve (DC) is an important characteristic of the propagation of surface waves in sedimentary environments. Although the procedure for DC estimation in onshore environments using ambient vibration recordings is well established, the DC estimation in offshore environments using Ocean Bottom Seismometers (OBS) array recordings of ambient vibrations presents three additional challenges: (1) the localization of sensors, (2) the orientation of the OBS horizontal components, and (3) the clock error. Here, we address these challenges in an inherent preprocessing workflow to ultimately extract the Love and Scholte wave DC from small aperture OBS array measurements performed between 2018 and 2020 in Lake Lucerne (Switzerland). The arrays have a maximum aperture of 679 m and a maximum deployment water depth of 81 m. The challenges related to the OBS location on the lake floor are addressed by combining the multibeam bathymetry map and the backscatter image for the investigated site with the differential GPS coordinates of the OBS at recovery. The OBS measurements are complemented by airgun surveys. Airgun data are first used to estimate the misorientation of the horizontal components of the OBS and second to estimate the clock error. To assess the robustness of the preprocessing workflow, we use two array processing methods, namely the three-component high-resolution frequency-wavenumber and the interferometric multichannel analysis of surface waves, to estimate the dispersion characteristics of the propagating Scholte and Love waves for one of the OBS array sites. The results show the effectiveness of the preprocessing workflow. We observe the phase-velocity dispersion curve branches in the frequency range between 1.2 and 3.2 Hz for both array processing techniques. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00024-021-02923-8.

Subaqueous geomorphology and delta dynamics of Lake Brienz (Switzerland): implications for the sediment budget in the alpine realm.

Non-invasive techniques such as seismic investigations and high-resolution multibeam sonars immensely improved our understanding of the geomorphology and sediment regimes in both the lacustrine and the marine domain. However, only few studies provide quantifications of basin wide-sediment budgets in lakes. Here, we use the combination of high-resolution bathymetric mapping and seismic reflection data to quantify the sediment budget in an alpine lake. The new bathymetric data of Lake Brienz reveal three distinct geomorphological areas: slopes with intercalated terraces, a flat basin plain, and delta areas with subaquatic channel systems. Quasi-4D seismic reflection data allow sediment budgeting of the lake with a total sediment input of 5.54 × 106 t sediment over 15 years of which three-quarter were deposited in the basin plain. Lake Brienz yields extraordinarily high sedimentation rates of 3.0 cm/yr in the basin plain, much more than in other Swiss lakes. This can be explained by (i) its role as first sedimentary sink in a high-alpine catchment, and by (ii) its morphology with subaquatic channel-complexes allowing an efficient sediment transfer from proximal to distal areas of the lake.

A tsunamigenic delta collapse and its associated tsunami deposits in and around Lake Sils, Switzerland.

Large lacustrine mass movements and delta collapses are increasingly being considered as potential tsunamigenic sources and therefore hazardous for the population and infrastructure along lakeshores. Although historical reports document tsunami events in several lakes in Switzerland, and although the propagation of lake tsunamis has been studied by numerical wave modeling, only little is known about on- and offshore lacustrine tsunami deposits. In Lake Sils, Switzerland, a large prehistoric mass-movement deposit originating from the Isola Delta with a minimum estimated volume of 6.5 × 106 m3 and a basinal thickness of > 6 m in the seismic record has been identified by previous studies and radiocarbon dated to around 700 Common Era. Here, we combine (i) comprehensive sedimentological investigation of sediment cores recovered from the on- and offshore settings, (ii) mineralogical fingerprinting of the inflows from key catchments to characterize sediment provenance, and (iii) numerical tsunami modeling, to test the hypothesis of a tsunamigenic delta collapse in Lake Sils. We observe a clastic event deposit consisting of coarse-grained, fining-upward sand overlying an organic-rich peat deposit in the shallow water. This layer thins and fines landward on the coastal plain. Toward the deeper water (20-40 m), the deposit transforms into a thicker and more heterogeneous sediment package with multiple sequences of fining-upward sand and a well-pronounced clay cap at the top. Radiocarbon dating of the peat underlying the event deposit yields a maximum age of 225-419 calibrated  Common Era. The tsunami models, which indicate wave heights reaching up to 5 m, simulate areas of inundation that coincide with the location of event deposits. Based on our results, we propose that the historically undocumented Isola Delta collapse generated a basin-wide tsunami that inundated the lakeshore, transporting large amounts of unconsolidated sediment along the lakeshore toward the coastal plain and into the deeper lake basin. SUPPLEMENTARY INFORMATION: The online version of this article (10.1007/s11069-021-04533-y) contains supplementary material, which is available to authorized users.