Long-term transmural drainage of pancreatic fluid collections with double pigtail stents following lumen-apposing metal stent placement improves recurrence-free survival in disconnected pancreatic duct syndrome.

OBJECTIVES: Disconnected pancreatic duct syndrome (DPDS) is the most common cause of pancreatic fluid collection (PFC) recurrence. While long-term transmural drainage with plastic stents is the preferred endoscopic approach, there is a paucity of literature on patients undergoing initial drainage with lumen-apposing metal stents (LAMS). We describe our experience managing patients with DPDS. METHODS: A retrospective review of a prospectively maintained database (November 2015-September 2020) was performed looking at clinical outcomes and overall survival for patients undergoing endoscopic management of PFCs using LAMS. The primary outcome was to assess recurrence-free survival in PFC patients with DPDS managed with or without double pigtail stents (DPS) replacement after LAMS removal. RESULTS: Of 96 patients with PFCs, 48 with DPDS were included in the study. The median follow-up was 20.1 months. LAMS replacement with DPS was successful in 21/48 (43.8%) patients. Recurrence was seen in 1/21 (5%) patients with DPS replacement and 10/27 (37%) without DPS replacement. In multivariable models, a longer duration of LAMS placement was negatively associated with successful DPS replacement (odds ratio 1.33, 95% confidence interval [CI] 1.11, 1.59, P = 0.0019) and successful LAMS replacement with DPS in patients with DPDS improved recurrence-free survival (hazard ratio 0.09, 95% CI 0.01, 0.83, P = 0.033). CONCLUSION: In patients with PFCs and DPDS, early replacement of LAMS with DPS improves the likelihood of successful long-term transmural drainage and decreases recurrences.

Modified frailty index predicts postoperative outcomes in older gastrointestinal cancer patients.

BACKGROUND AND OBJECTIVES: Frailty disproportionately impacts older patients with gastrointestinal cancer, rendering them at increased risk for poor outcomes. A frailty index may aid in preoperative risk stratification. We hypothesized that high modified frailty index (mFI) scores are associated with adverse outcomes after tumor resection in older, gastrointestinal cancer patients. METHODS: Patients (60-90 years old) who underwent gastrointestinal tumor resection were identified in the 2005-2012 NSQIP Participant Use File. mFI was defined by 11 previously described, preoperative variables. Frailty was defined by an mFI score >0.27. The postoperative course was evaluated using univariate and multivariate analysis. RESULTS: 41 455 patients (mean age 72.4 years, 47.4% female) were identified. The most prevalent form of cancer was colorectal (69.3%, n = 28 708) and 2.8% of patients were frail (n = 1,164). Frail patients were significantly more likely to have increased length of stay (11.7 vs 9.0 days), major complications (29.1% vs 17.9%), and 30-day mortality (5.6% vs 2.5%), (all P < 0.001). Multivariate analysis identified mFI as an independent predictor of major complications (OR 1.52, 95%CI 1.39-1.65, P < 0.001) and 30-day mortality (OR 1.48, 95%CI 1.24-1.75, P < 0.001). CONCLUSIONS: mFI was associated with the incidence of postoperative complications and mortality in older surgical patients with gastrointestinal cancer.

Feasibility of real-time location systems in monitoring recovery after major abdominal surgery.

BACKGROUND: Early mobilization after major abdominal surgery decreases postoperative complications and length of stay, and has become a key component of enhanced recovery pathways. However, objective measures of patient movement after surgery are limited. Real-time location systems (RTLS), typically used for asset tracking, provide a novel approach to monitoring in-hospital patient activity. The current study investigates the feasibility of using RTLS to objectively track postoperative patient mobilization. METHODS: The real-time location system employs a meshed network of infrared and RFID sensors and detectors that sample device locations every 3 s resulting in over 1 million data points per day. RTLS tracking was evaluated systematically in three phases: (1) sensitivity and specificity of the tracking device using simulated patient scenarios, (2) retrospective passive movement analysis of patient-linked equipment, and (3) prospective observational analysis of a patient-attached tracking device. RESULTS: RTLS tracking detected a simulated movement out of a room with sensitivity of 91% and specificity 100%. Specificity decreased to 75% if time out of room was less than 3 min. All RTLS-tagged patient-linked equipment was identified for 18 patients, but measurable patient movement associated with equipment was detected for only 2 patients (11%) with 1-8 out-of-room walks per day. Ten patients were prospectively monitored using RTLS badges following major abdominal surgery. Patient movement was recorded using patient diaries, direct observation, and an accelerometer. Sensitivity and specificity of RTLS patient tracking were both 100% in detecting out-of-room ambulation and correlated well with direct observation and patient-reported ambulation. CONCLUSION: Real-time location systems are a novel technology capable of objectively and accurately monitoring patient movement and provide an innovative approach to promoting early mobilization after surgery.

Hydrodynamics of fossil fishes.

From their earliest origins, fishes have developed a suite of adaptations for locomotion in water, which determine performance and ultimately fitness. Even without data from behaviour, soft tissue and extant relatives, it is possible to infer a wealth of palaeobiological and palaeoecological information. As in extant species, aspects of gross morphology such as streamlining, fin position and tail type are optimized even in the earliest fishes, indicating similar life strategies have been present throughout their evolutionary history. As hydrodynamical studies become more sophisticated, increasingly complex fluid movement can be modelled, including vortex formation and boundary layer control. Drag-reducing riblets ornamenting the scales of fast-moving sharks have been subjected to particularly intense research, but this has not been extended to extinct forms. Riblets are a convergent adaptation seen in many Palaeozoic fishes, and probably served a similar hydrodynamic purpose. Conversely, structures which appear to increase skin friction may act as turbulisors, reducing overall drag while serving a protective function. Here, we examine the diverse adaptions that contribute to drag reduction in modern fishes and review the few attempts to elucidate the hydrodynamics of extinct forms.

Circulation of hydraulically ponded turbidity currents and the filling of continental slope minibasins.

Natural depressions on continental margins termed minibasins trap turbidity currents, a class of sediment-laden seafloor density driven flow. These currents are the primary downslope vectors for clastic sediment, particulate organic carbon, and microplastics. Here, we establish a method that facilitates long-distance self-suspension of dilute sediment-laden flows, enabling study of turbidity currents with appropriately scaled natural topography. We show that flow dynamics in three-dimensional minibasins are dominated by circulation cell structures. While fluid rotation is mainly along a horizontal plane, inwards spiraling flow results in strong upwelling jets that reduce the ability of minibasins to trap particulate organic carbon, microplastics, and fine-grained clastic sediment. Circulation cells are the prime mechanism for distributing particulates in minibasins and set the geometry of deposits, which are often intricate and below the resolution of geophysical surveys. Fluid and sediment are delivered to circulation cells by turbidity currents that runup the distal wall of minibasins. The magnitude of runup increases with the discharge rate of currents entering minibasins, which influences the amount of sediment that is either trapped in minibasins or spills to downslope environs and determines the height that deposits onlap against minibasin walls.

Clinical outcomes of long-term transmural drainage with double pigtail stents in disconnected pancreatic duct syndrome.

Background: Disconnected pancreatic duct syndrome (DPDS) is a common cause of recurrent pancreatic fluid collections (PFCs), often requiring repeat drainage. Following initial drainage with lumen apposing metal stents (LAMS), replacement with transmural double pigtail stents (DPS) has been shown to be a viable drainage modality mitigating the risk of recurrence. The sparsity of literature on the consequences of this strategy requires further investigation. We analyze our outcomes of long-term transmural drainage with DPS in patients with DPDS and assess the safety and efficacy of this technique. Methods: This retrospective review of a prospectively maintained database from November 2015-May 2022 included all patients with DPDS who underwent removal of LAMS and replacement with long-term transmural DPS. Patient demographics, collection characteristics, drainage technique and outcomes, as well as follow-up data was collected and analyzed using descriptive statistics. Results: There were 139 patients who underwent endoscopic drainage of PFCs with LAMS during the study period. Seventy-eight patients [walled-off necrosis (n=65) and pseudocysts (n=13)] were found to have DPDS. Of these, 44 patients underwent successful LAMS removal followed by replacement with DPS and were included in the analysis. The median age was 57 years and 14 (32%) were female. The median stent dwell time was 394 days [interquartile range (IQR) 245, 853 days]. Spontaneous stent migration was seen in seven patients (16%), one of whom developed a PFC recurrence which was managed conservatively. The second recurrence was seen in a patient with indwelling DPS which did not require further intervention. There were no locoregional adverse events secondary to long-term indwelling DPS. Among the 28 patients who were followed for a year, three patients developed new-onset diabetes, and chronic pancreatitis (CP) changes in the disconnected segment were seen in eight patients, five of whom required pancreatic enzyme supplementation. Conclusions: Placement of long-term transmural DPS is an effective modality for preventing collection re-accumulation with a favorable safety profile. Randomized prospective studies are essential to investigate the optimal removal timing of indwelling stents to prevent loco-regional complications. Given the realized risk of CP in the disconnected pancreas, follow-up cross sectional imaging may help guide further therapy.

Analysis of adverse events with lumen apposing metal stents for drainage of pancreatic fluid collections.

Background and study aims Innovations in endoscopic management of pancreatic fluid collections (PFCs) using lumen apposing metal stents (LAMS) have rendered it a preferred approach for drainage of PFCs. These advances have not come without concern for adverse events (AEs). We present our experience with LAMS for drainage of PFCs and analyze factors that contribute to LAMS-related AEs. Patients and methods From November 2015 to October 2021, a retrospective analysis was performed of patients undergoing endoscopic management of PFCs using LAMS. All AEs were classified as either early (<48 hours) or late (>48 hours). Univariate and multivariate analysis were performed using logistic regression to assess the relationship between independent variables and AEs. Results A total of 119 patients with symptomatic PFCs underwent endoscopic drainage with LAMS. There were 16 AEs (12.4%). These included systemic inflammatory response syndrome (SIRS) (n=2), stent occlusion (n=5), bleeding (n=7), and stent migration (n=2). Univariate analysis of risk of AEs showed that no variables approached statistical significance. Of the seven patients who developed bleeding, five had pseudoaneurysms following LAMS placement and underwent angioembolization by an interventional radiologist. The average time to bleeding was 9.3 days (standard deviation 7.3) with all bleeding events occurring within 3 weeks. In a multivariate model, pseudocysts and presence of paracolic gutter extension were associated with an increased risk of bleeding. Conclusions Endoscopists should be aware of the risk factors for LAMS-related bleeding and tailor their drainage strategy, including utilization of plastic stents for drainage of pseudocysts and adherence to a strict imaging interval and follow-up protocol.

Delayed endoscopic necrosectomy improves hospital length of stay and reduces endoscopic interventions in patients with symptomatic walled-off necrosis.

Objectives: Advancements in the endoscopic management of walled-off necrosis using lumen apposing metal stents have improved outcomes over its surgical and percutaneous alternatives. The ideal procedural technique and timing of direct endoscopic necrosectomy (DEN) have yet to be clarified. Methods: From November 2015 to June 2021, a retrospective comparative cohort analysis was performed comparing clinical outcomes for patients undergoing immediate DEN (iDEN) versus delayed DEN (dDEN). Subgroups were identified based on the quantification of necrosis. Wilcoxon two-sample tests were used to compare continuous variables and Fisher's exact test was used to compare categorical variables. Results: A total of 80 patients underwent DEN for management of walled-off necrosis (iDEN = 43, dDEN = 37). Technical success was achieved in all patients. Clinical success was seen in 39 (91%) patients in the iDEN group and 34 (92%) in the dDEN group. Amongst iDEN patients, the mean number of necrosectomies was 2.5 (standard deviation [SD] 1.4) in comparison to 1.5 (SD 1.0) for dDEN (p-value = 0.0011). The median index hospital length of stay was longer with iDEN than dDEN (7.5 days vs. 3.0 days respectively, p-value = 0.010). Subgroup analysis was performed based on the percentage of necrosis (<25% vs. >25% necrosis). iDEN was associated with more necrosectomies than dDEN regardless of the percentage of necrosis (p = 0.017 and 0.0067, respectively). Conclusion: Patients undergoing dDEN had a shorter index hospital stay and fewer necrosectomies than iDEN. The large diameter of lumen apposing metal stents permits adequate drainage allowing a less aggressive approach thereby improving clinical outcomes and avoiding unnecessary interventions.

Endoscopic management of hemorrhagic pancreatic fluid collections: A propensity-matched analysis.

Objectives: Hemorrhagic pancreatic fluid collections (hPFC) are a complication of pancreatitis with an unknown influence on prognosis. Advancements in endoscopic management of PFC have improved results over their surgical and percutaneous alternatives. We performed a propensity-matched analysis comparing clinical outcomes in hemorrhagic and non-hemorrhagic PFC (nhPFC). Methods: From November 2015 to November 2021, a retrospective comparative cohort analysis was performed comparing clinical outcomes for patients with hPFC and nhPFC managed with lumen-apposing metal stents. Propensity score matching was used to balance the two subgroups. Wilcoxon two-sample tests were used to compare continuous variables and Fisher's exact test was used to compare categorical variables. Kaplan-Meier method was used to estimate overall survival. Results: Fifteen patients with hPFC were matched with 30 nhPFC patients. Technical and clinical success was similar in both groups. The median length of hospitalization was 6 days in the hPFC group and 3 days in the nhPFC group (p = 0.23); however, more hPFC patients required intensive care unit admission post-procedure (33.3% vs. 16.7%, p = 0.26). Patients with hPFC were more likely to be readmitted to the hospital within 30 days (33.3% vs. 6.7%, p = 0.032). Mortality at 3 months (13% vs 3%, p = 0.25) and 6 months (27% vs. 7%, p = 0.09) was higher in the hPFC cohort. The 1-year survival estimate was 73.3% (standard error = 11.4) in the hPFC group and 88.9% (6.1) in the nhPFC group (p = 0.16). Conclusions: Patients with hPFC are more likely to be readmitted to the hospital within 30 days and have worse clinical outcomes.

Inadequacy of fluvial energetics for describing gravity current autosuspension.

Gravity currents, such as sediment-laden turbidity currents, are ubiquitous natural flows that are driven by a density difference. Turbidity currents have provided vital motivation to advance understanding of this class of flows because their enigmatic long run-out and driving mechanisms are not properly understood. Extant models assume that material transport by gravity currents is dynamically similar to fluvial flows. Here, empirical research from different types of particle-driven gravity currents is integrated with our experimental data, to show that material transport is fundamentally different from fluvial systems. Contrary to current theory, buoyancy production is shown to have a non-linear dependence on available flow power, indicating an underestimation of the total kinetic energy lost from the mean flow. A revised energy budget directly implies that the mixing efficiency of gravity currents is enhanced.

Endoscopic management of cystic duct stones and Mirizzi's syndrome: experience at an academic medical center.

Background and study aims Cystic duct stones (CDS) are challenging to treat with conventional ERCP techniques due to the small diameter and tortuous nature of the cystic duct. There have been limited studies focused on endoscopic management of CDS. We present our experience managing CDS endoscopically and demonstrate that new advances in endoscopic technology have rendered CDS easier to manage. Patients and methods From 2013 to 2020, we prospectively maintained a database of patients undergoing endoscopic management of CDS. ERCP was performed in all patients, and if unsuccessful in removing stones, cholangioscopy with electrohydraulic lithotripsy (EHL) was utilized. All patients were followed in clinic for outcomes. Results Of 5,123 ERCPs performed at our institution during the study period, 21 patients were diagnosed with CDS. Six patients were successfully treated with conventional ERCP alone. Cholangioscopy with EHL was used in 15 patients undergoing 18 procedures to achieve stone clearance. CDS clearance was achieved in all patients. There was one adverse event (post-ERCP pancreatitis). Spyglass DS was associated with a significant decrease in average procedure time in comparison to first-generation SpyGlass (89.3 vs. 54.4 minutes, P  = 0.004). Thirteen patients (87 %) were discharged from the hospital within 24 hours. The median follow-up duration was 23.2 months. Conclusions Endoscopy should be the preferred management strategy for CDS, especially in patients with prior cholecystectomy. Surgical outcomes have been associated with high patient morbidity and hospital length of stay. Our case series is the largest cohort of CDS patients successfully managed with cholangioscopy and EHL in the United States.

Endoscopic Management of Pancreatic Fluid Collections.

Pancreatic fluid collections (PFCs) are a common sequela of pancreatitis. Most PFCs can be managed conservatively, but symptomatic PFCs require either surgical, percutaneous, or endoscopic intervention. Recent advances in the therapeutics of PFCs, including the step-up approach, endoscopic ultrasound-guided transmural drainage with lumen apposing metal stents, and direct endoscopic necrosectomy, have ushered endoscopy to the forefront of PFCs management and have allowed for improved patient outcomes and decreased morbidity. In this review, we explore the progress and future of endoscopic management of PFCs.

Hydrodynamic efficiency in sharks: the combined role of riblets and denticles.

We investigate the influence of smooth and ribletted shark skin on a turbulent boundary layer flow. Through laser Doppler anemometry (LDA) the role of riblets in combination with the shark skin denticle is established for the first time. Our results show that smooth denticles behave like a typical rough surface when exposed to an attached boundary layer. Drag is increased for the full range of tested dimensionless denticle widths,w+≈ 25-80, wherew+is the denticle width,w, scaled by the friction velocity,uτ, and the kinematic viscosity,ν. However, when riblets are added to the denticle crown we demonstrate there is a significant reduction in drag, relative to the smooth denticles. We obtain a modest maximum drag reduction of 2% for the ribletted denticles when compared to the flat plate, but when compared to the smooth denticles the difference in drag is in excess of 20% forw+≈ 80. This study enables a new conclusion that riblets have evolved as a mechanism to reduce or eliminate the skin friction increase due to the presence of scales (denticles). The combination of scales and riblets is hydrodynamically efficient in terms of skin-friction drag, while also acting to maintain flow attachment, and providing the other advantages associated with scales, e.g. anti-fouling, abrasion resistance, and defence against parasites.

Gastrointestinal and hepatic manifestations of COVID-19: A systematic review and meta-analysis.

Background and Aim: This review investigates the role of gastrointestinal and hepatic manifestations in COVID-19, particularly with regard to the prevalence of isolated gastrointestinal (GI) symptoms. Methods: We searched PubMed, Embase, and Cochrane library for COVID-19 publications from 1 December 2019 to 18 May 2020. We included any study that reported the presence of GI symptoms in a sample of >5 COVID-19 patients. Data collection and risk of bias assessment were performed independently by two reviewers. Where ≥3 studies reported data sufficiently similar to allow calculation of a pooled prevalence, we performed random effects meta-analysis. Results: This review included 17 776 COVID-19 patients from 108 studies. Isolated GI symptoms only occurred in 1% (95% confidence interval [CI] 0-6%) of patients. GI symptoms were reported in 20% (95% CI 15-24%) of patients. The most common were anorexia (21%, 95% CI 15-27%), diarrhea (13%, 95% CI 11-16%), nausea or vomiting (8%, 95% CI 6-11%), and abdominal pain (4%, 95% CI 2-6%). Transaminase elevations were present in 24% (95% CI 17-31%) of patients. Higher prevalence of GI symptoms were reported in studies published after 1st April, with prevalence of diarrhea 16% (95% CI 13-20), nausea or vomiting 12% (95% CI 8-16%), and any GI symptoms 24% (95% CI 18-34%). GI symptoms were associated with severe COVID-19 disease (odds ratio [OR] 2.1, 95% CI 1.3-3.2), but not mortality (OR 0.90, 95% CI 0.52-1.54). Conclusions: Patients with isolated GI symptoms may represent a small but significant portion of COVID-19 cases. When testing resources are abundant, clinicians should still consider testing patients with isolated GI symptoms or unexplained transaminase elevations for COVID-19. More recent studies estimate higher overall GI involvement in COVID-19 than was previously recognized.

Endoscopic Management of Malignant Biliary Stricture.

A biliary stricture is an area of narrowing in the extrahepatic or intrahepatic biliary system. The majority of biliary strictures are caused by malignancies, particularly cholangiocarcinoma and pancreatic adenocarcinoma. Most malignant biliary strictures are unresectable at diagnosis. Treatment of these diseases historically required surgical procedures, however, the development of endoscopic techniques has provided alternative minimally invasive treatment options to improve patient quality of life and survival with unresectable disease. While endoscopic retrograde cholangiopancreatography with stent placement has been the cornerstone of biliary drainage for decades, cutting edge endoscopic developments, including radiofrequency ablation and endoscopic ultrasound-guided biliary drainage, offer new therapy options to patients that historically have a poor quality of life and a grim prognosis. In this review, we explore the endoscopic techniques that have contributed to revolutionary advancements in the endoscopic management of malignant biliary strictures.

Antegrade Therapy for Management of Choledocholithiasis through Endoscopic Ultrasound-Guided Hepaticogastrostomy in a Patient with Surgically Altered Gastrointestinal Anatomy.

Endoscopic ultrasound-guided hepaticogastrostomy (EUS-HG) is a technique used to access the biliary tree in patients with surgically altered anatomy. Additionally, development of EUS-HG fistula permits intraductal therapy, thereby preventing patients from requiring surgery or percutaneous transhepatic biliary drainage (PTBD), thus decreasing morbidity. This clinical vignette describes an 83-year-old man with a history of gangrenous cholecystitis requiring cholecystectomy, partial gastrectomy, and Roux-en-Y gastrojejunostomy who presented to an outside hospital with abdominal pain and fever and found to have cholangitis and choledocholithiasis. He underwent two endoscopic retrograde cholangiopancreatography (ERCP) procedures at an outside hospital which were unsuccessful due to an inaccessible major papilla in the setting of the patient's surgically altered anatomy. On arrival to Wake Forest, the patient underwent EUS-HG with successful biliary drainage and resolution of cholangitis. He returned for ERCP three months later with balloon sphincteroplasty, cholangioscopy, and electrohydraulic lithotripsy (EHL) performed through the existing metal stent (hepaticogastrostomy), resulting in stone fragmentation and antegrade removal with balloon sweeps. Repeat cholangioscopy post-EHL and balloon sweeps showed complete duct clearance with no residual stones. The hepaticogastrostomy stent was subsequently removed, and the patient recovered without any complications.

The Diagnostic Dilemma of Malignant Biliary Strictures.

The differential diagnosis for biliary strictures is broad. However, the likelihood of malignancy is high. Determining the etiology of a biliary stricture requires a comprehensive physical exam, laboratory evaluation, imaging, and ultimately tissue acquisition. Even then, definitive diagnosis is elusive, and many strictures remain indeterminant in origin. This literary review examines the diagnostic dilemma of biliary strictures and presents innovations in both histochemical and endoscopic techniques that have increased the diagnostic power of differentiating benign and malignant strictures. The field of tissue biopsy is revolutionizing with the advent of free DNA mutation profiling, fluorescence in situ hybridization (FISH), and methionyl t-RNA synthetase 1 (MARS 1), which allow for greater testing sensitivity. Endoscopic ultrasound, endoscopic retrograde cholangiopancreatography (ERCP), cholangioscopy, confocal laser endomicroscopy, and intraductal ultrasound build upon existing endoscopic technology to better characterize strictures that would otherwise be indeterminate in etiology. This review uses recent literature to insert innovative technology into the traditional framework of diagnostic methods for malignant biliary strictures.