To compare the clinical outcomes of endoscopic biliary drainage (EBD) with those of percutaneous transhepatic biliary drainage (PTBD) in patients with resectable hilar cholangiocarcinoma (HCCA) and ...evaluate the effect of EBD and PTBD on tumor prognosis.
PubMed, EMBASE, and Cochrane Library databases were searched for articles about the comparison between PTBD and EBD. Data were analyzed by Revman 5.3.
PTBD showed a lower risk of drainage-related complications than EBD (OR, 2.73; 95%CI, 1.52-4.91; P < .05). PTBD was also associated with lower risk of pancreatitis (OR, 8.47; 95%CI, 2.28-31.45; P < .05). The differences in preoperative cholangitis, R0 resection, blood loss and recurrence showed no statistically significance between EBD and PTBD (all P > .05). Several literatures have reported the tumor implantation metastasis after PTBD. Since no well-designed prospective randomized controlled studies have explored in this depth, this article is unable to draw conclusions on this aspect.
PTBD is a reasonable choice for PBD, and EBD should only be used as preoperative drainage for HCCA by more experienced physicians. There is a greater need to design prospective randomized controlled studies to obtain high-level evidence-based medicinal proof. It is worth noting that, whether EBD or PTBD, accurate selective biliary drainage should be the trend.
Endoscopic ultrasound-guided gallbladder drainage (EUS-GBD) has been introduced as an alternative to percutaneous transhepatic gallbladder drainage for the treatment of acute cholecystitis in ...non-surgical candidates. A systematic review of the English language literature through PubMed search until June 2014 was conducted. One hundred and fifty-five patients with acute cholecystitis treated with EUS-GBD in eight studies and 12 case reports, and two patients with EUS-GBD for other causes were identified. Overall, technical success was obtained in 153 patients (97.45%) and clinical success in 150 (99.34%) patients with acute cholecystitis. Adverse events developed in less than 8% of patients, all of them managed conservatively. EUS-GBD has been performed with plastic stents, nasobiliary drainage tubes, standard or modified tubular self-expandable metal stents (SEMS) and lumen-apposing metal stents (LAMS) by different authors with apparently similar outcomes. No comparison studies between stent types for EUS-GBD have been reported. EUS-GBD is a promising novel alternative intervention for the treatment of acute cholecystitis in high surgical risk patients. Feasibility, safety and efficacy in published studies from expert centers are very high compared to currently available alternatives. Further studies are needed to establish the safety and long-term outcomes of this procedure in other practice settings before EUS-GBD can be widely disseminated.
The impact of controlled drainage (CD) on the groundwater table (GWT), drainage outflow, surface runoff, and nitrogen reduction at the drainage system scale in the Wielkopolska region was analyzed in ...this study. Based on field research, mainly by monitoring of GWT changes in 2019–2020, the DRAINMOD model was calibrated and validated. Hydrological soil water balance simulations were carried out with 36 and 9 combinations for CD and free drainage (FD), respectively. The modelling period was March-September for 10 different dry, wet, and normal years from the period of 1961 to 2020. The next step was to use the results of drainage outflow modelling and chemical constituent analyses of drainage water samples to determine NO3-N concentrations and calculate NO3-N pollution loads. As a result of the simulations, the importance of the timing of the start of the outflow retention in the adopted model variants was determined, indicating the earliest assumed date of 1 March. The appropriate CD start date as well as the initial GWT has a significant impact on the effectiveness of CD application in reducing the volume of drainage outflow and reducing the amount of NO3-N entering open water with it. The application of CD under the conditions of the analyzed drainage facility makes it possible to retain up to 22 kg of NO3-N per hectare.
The introduction of lumen-apposing metal stents (LAMS) for endoscopic ultrasound (EUS)-guided drainages has marked a turning point in the field of interventional ultrasound and it is gathering ...worldwide diffusion in different clinical settings. Nevertheless, the procedure may conceal unexpected pitfalls. LAMS misdeployment is the most frequent cause of technical failure and it can be considered a procedure-related adverse event when it hampers the conclusion of the planned procedure or results in significant clinical consequences. Stent misdeployment can be managed successfully by endoscopic rescue maneuvers to allow the completion of the procedure. To date, no standardized indication is available to guide an appropriate rescue strategy depending on the type of procedure or of misdeployment.
To evaluate the incidence of LAMS misdeployment during EUS-guided choledochoduodenostomy (EUS-CDS), gallbladder drainage (EUS-GBD) and pancreatic fluid collections drainage (EUS-PFC) and to describe the endoscopic rescue strategies adopted under the circumstance.
We conducted a systematic review of the literature on PubMed by searching for studies published up to October 2022. The search was carried out using the exploded medical subject heading terms "lumen apposing metal stent", "LAMS", "endoscopic ultrasound" and "choledochoduodenostomy" or "gallbladder" or "pancreatic fluid collections". We included in the review on-label EUS-guided procedures namely EUS-CDS, EUS-GBD and EUS-PFC. Only those publications reporting EUS-guided LAMS positioning were considered. The studies reporting a technical success rate of 100% and other procedure-related adverse events were considered to calculate the overall rate of LAMS misdeployment, while studies not reporting the causes of technical failure were excluded. Case reports were considered only for the extraction of data regarding the issues of misdeployment and rescue techniques. The following data were collected from each study: Author, year of publication, study design, study population, clinical indication, technical success, reported number of misdeployment, stent type and size, flange misdeployed and type of rescue strategy.
The overall technical success rate of EUS-CDS, EUS-GBD and EUS-PFC was 93.7%, 96.1%, and 98.1% respectively. Significant rates of LAMS misdeployment have been reported for EUS-CDS, EUS-GBD and EUS-PFC drainage, respectively 5.8%, 3.4%, and 2.0%. Endoscopic rescue treatment was feasible in 86.8%, 80%, and 96.8% of cases. Non endoscopic rescue strategies were required only in 10.3%, 16% and 3.2% for EUS-CDS, EUS-GBD, and EUS-PFC. The endoscopic rescue techniques described were over-the-wire deployment of a new stent through the created fistula tract in 44.1%, 8% and 64.5% and stent-in-stent in 23.5%, 60%, and 12.9%, respectively for EUS-CDS, EUS-GBD, and EUS-PFC. Further therapeutic option were endoscopic rendezvous in 11.8% of EUS-CDS and repeated procedure of EUS-guided drainage in 16.1% of EUS-PFC.
LAMS misdeployment is a relatively common adverse event in EUS-guided drainages. There is no consensus on the best rescue approach in these cases and the choice is often made by the endoscopist relying upon the clinical scenario, anatomical characteristics, and local expertise. In this review, we investigated the misdeployment of LAMS for each of the on-label indications focusing on the rescue therapies used, with the aim of providing useful data for endoscopists and to improve patient outcomes.
The performance of urban drainage systems is typically examined using hydrological and hydrodynamic models where rainfall input is uniformly distributed, i.e., derived from a single or very few rain ...gauges. When models are fed with a single uniformly distributed rainfall realization, the response of the urban drainage system to the rainfall variability remains unexplored. The goal of this study was to understand how climate variability and spatial rainfall variability, jointly or individually considered, affect the response of a calibrated hydrodynamic urban drainage model. A stochastic spatially distributed rainfall generator (STREAP – Space-Time Realizations of Areal Precipitation) was used to simulate many realizations of rainfall for a 30-year period, accounting for both climate variability and spatial rainfall variability. The generated rainfall ensemble was used as input into a calibrated hydrodynamic model (EPA SWMM – the US EPA's Storm Water Management Model) to simulate surface runoff and channel flow in a small urban catchment in the city of Lucerne, Switzerland. The variability of peak flows in response to rainfall of different return periods was evaluated at three different locations in the urban drainage network and partitioned among its sources. The main contribution to the total flow variability was found to originate from the natural climate variability (on average over 74 %). In addition, the relative contribution of the spatial rainfall variability to the total flow variability was found to increase with longer return periods. This suggests that while the use of spatially distributed rainfall data can supply valuable information for sewer network design (typically based on rainfall with return periods from 5 to 15 years), there is a more pronounced relevance when conducting flood risk assessments for larger return periods. The results show the importance of using multiple distributed rainfall realizations in urban hydrology studies to capture the total flow variability in the response of the urban drainage systems to heavy rainfall events.
The Denitrification Decomposition model (DNDC) has known limitations for simulating soil hydrology which can strongly influence biogeochemical processes. For this study, DNDC's soil hydrological ...framework was enhanced by including a new sub-model for mechanistic tile drainage, improved water flux, root growth dynamics, and a deeper and heterogeneous soil profile. Comparisons were then conducted against the Root Zone Water Quality Model (RZWQM2), using measurements of soil water storage, runoff, and drainage in eastern Canada and the US Midwest. Simulation of soil water storage (DNDC 0.81 ≤ d ≤ 0.90; RZWQM2 0.76 ≤ d ≤ 0.84), daily water flow (DNDC 0.76 ≤ d ≤ 0.88; RZWQM2 0.77 ≤ d ≤ 0.90) and nitrogen loading to tile drains were improved post-development. DNDC was able to capture the observed differences in water and N losses between conventional drainage and controlled drainage management with sub-irrigation. The enhancements to DNDC's hydrological framework should enable the development of improved biogeochemical processes.
•Developed Canada DNDC to improve simulation of soil hydrology and tile drainage.•Incorporated a fluctuating water table, heterogeneous profile and root functions.•DNDC performed similarly to RZWQM2 for yields, hydrology and tile drainage.•DNDC was improved for simulating soil water, daily drainage, and N loading.
Background Controversy exists over the preferred technique of preoperative biliary drainage (PBD) in patients with hilar cholangiocarcinoma (HCA). The goal of this retrospective study was to identify ...the preferred technique of PBD for HCA. Methods A total of 128 consecutive patients with HCA diagnosed between September 1999 and December 2009 who underwent PBD were included in this study. The study compared outcomes of endoscopic nasobiliary drainage (ENBD), endoscopic biliary stenting (EBS), and percutaneous transhepatic biliary drainage (PTBD) in patients with HCA. Results There were no significant differences in preoperative laboratory data, rates of major hepatectomy, or decompression periods among the 3 groups. Complications were significantly more frequent in the EBS group compared with either the ENBD or PTBD group (p < 0.05). Drainage tube occlusion with cholangitis was significantly more common in the EBS group compared with either the ENBD or PTBD group (p < 0.0001). Patients in the PTBD group experienced serious complications including vascular injury (8%) and cancer dissemination (4%). Patients in the ENBD and EBS groups had mild post-endoscopic retrograde cholangiopancreatography pancreatitis (5%). Conversion procedures were significantly more common in the EBS group compared with the ENBD and PTBD groups (p < 0.05). There was no significant difference in postsurgical morbidity or mortality among the 3 groups. Conclusions Drainage tube occlusion with cholangitis was a frequent complication associated with EBS. PTBD was associated with serious complications such as vascular injury and cancer dissemination. ENBD was found to be the most suitable method for initial PBD management in patients with HCA.
We investigated the scaling and topology of engineered urban drainage networks (UDNs) in two cities, and further examined UDN evolution over decades. UDN scaling was analyzed using two power law ...scaling characteristics widely employed for river networks: (1) Hack's law of length (L)‐area (A)
L∝Ah and (2) exceedance probability distribution of upstream contributing area (δ)
P(A≥δ)∼aδ−ɛ. For the smallest UDNs (<2 km2), length‐area scales linearly (h ∼ 1), but power law scaling (h ∼ 0.6) emerges as the UDNs grow. While
P(A≥δ) plots for river networks are abruptly truncated, those for UDNs display exponential tempering
P(A≥δ)=aδ−ɛexp(−cδ). The tempering parameter c decreases as the UDNs grow, implying that the distribution evolves in time to resemble those for river networks. However, the power law exponent ɛ for large UDNs tends to be greater than the range reported for river networks. Differences in generative processes and engineering design constraints contribute to observed differences in the evolution of UDNs and river networks, including subnet heterogeneity and nonrandom branching.
Plain Language Summary
We show that urban drainage networks (UDNs) evolve to the state topologically similar to rivers: UDNs exhibit self‐similarity as they grow beyond a small threshold size, like river networks. We present the gradual emergence of two power laws for UDNs ‐ Hack's law and the size distribution ‐ during decadal growth of two distinct cities. Although an initial UDN reflects the strong influence of engineering design, expanding UDN along with urban growth leads to a scale‐invariant topology. The power laws emerge during growth with exponents similar to those seen for rivers. The inevitability of the self‐similar topology has significant implications for managing urban drainage infrastructure in the rapidly urbanizing world, with increasing demands on reliable provision of critical services to growing populations.
Key Points
Urban drainage networks are self‐similar, obeying power law scaling similar to those reported for river networks
As urban drainage networks grow, their topology becomes similar with that of river networks in terms of power law truncation
River and urban drainage networks differ in the space‐filling constraint and the configuration at the scale below the power law threshold
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