Loss-free tensile ductility of dual-structure titanium composites via an interdiffusion and self-organization strategy.

The deformation-coordination ability between ductile metal and brittle dispersive ceramic particles is poor, which means that an improvement in strength will inevitably sacrifice ductility in dispersion-strengthened metallic materials. Here, we present an inspired strategy for developing dual-structure-based titanium matrix composites (TMCs) that achieve 12.0% elongation comparable to the matrix Ti6Al4V alloys and enhanced strength compared to homostructure composites. The proposed dual-structure comprises a primary structure, namely, a TiB whisker-rich region engendered fine grain Ti6Al4V matrix with a three-dimensional micropellet architecture (3D-MPA), and an overall structure consisting of evenly distributed 3D-MPA "reinforcements" and a TiBw-lean titanium matrix. The dual structure presents a spatially heterogeneous grain distribution with 5.8 µm fine grains and 42.3 µm coarse grains, which exhibits excellent hetero-deformation-induced (HDI) hardening and achieves a 5.8% ductility. Interestingly, the 3D-MPA "reinforcements" show 11.1% isotropic deformability and 66% dislocation storage, which endows the TMCs with good strength and loss-free ductility. Our enlightening method uses an interdiffusion and self-organization strategy based on powder metallurgy to enable metal matrix composites with the heterostructure of the matrix and the configuration of reinforcement to address the strength-ductility trade-off dilemma.

Rose bengal-decorated rice husk-derived silica nanoparticles enhanced singlet oxygen generation for antimicrobial photodynamic inactivation.

Rice husks are well known for their high silica content, and the RH-derived silica nanoparticles (RH NPs) are amorphous and biocompatible; therefore, they are suitable raw materials for biomedical applications. In this study, rose bengal-impregnated rice husk nanoparticles (RB-RH NPs) were prepared for their potential photosensitization and 1O2 generation as antimicrobial photodynamic inactivation. RB is a halogen-xanthene type's photosensitizer showing high singlet oxygen efficiency, and the superior photophysical properties are desirable for RB in the antimicrobial photodynamic inactivation of bacteria. To enhance the binding of anionic RB to RH NPs, we conducted cationization for the RH NPs using polyethyleneimine (PEI). The control of the RB adsorption state on cationic PEI-modified RH NPs was essential for RB RH-NP photosensitizers to obtain efficient 1O2 generation. Minimizing RB aggregation allowed highly efficient 1O2 production from RB-RH NPs at the molar ratio of RB with the PEI, XRB/PEI. = 0.1. The RB-RH NPs have significant antimicrobial activity against Streptococcus mutans compared to free RB after white light irradiation. The RB-RH NP-based antimicrobial photodynamic inactivation can be employed effectively in treating Streptococcus mutans for dental applications. Supplementary Information: The online version contains supplementary material available at 10.1007/s10853-023-08194-z.

Quantitative Strengthening Evaluation of Powder Metallurgy Titanium Alloys with Substitutional Zr and Interstitial O Solutes via Homogenization Heat Treatment.

The decomposition behavior of ZrO2 particles and uniform distribution of Zr and O solutes were investigated by employing in situ scanning electron microscope-electron backscatter diffraction (SEM-EBSD) analysis and thermogravimetric-differential thermal analysis (TG-DTA) to optimize the process conditions in preparing Ti-Zr-O alloys from the pre-mixed pure Ti powder and ZrO2 particles. The extruded Ti-Zr-O alloys via homogenization and water-quenching treatment were found to have a uniform distribution of Zr and O solutes in the matrix and also showed a remarkable improvement in the mechanical properties, for example, the yield stress of Ti-3 wt.% ZrO2 sample (1144.5 MPa) is about 2.5 times more than the amount of yield stress of pure Ti (471.4 MPa). Furthermore, the oxygen solid-solution was dominant in the yield stress increment, and the experimental data agreed well with the calculation results estimated using the Hall-Petch equation and Labusch model.

Mechanical properties and biocompatibility of titanium with a high oxygen concentration for dental implants.

In order to improve the strength of commercially pure Ti (CP-Ti) for oral implants, the high oxygen content Ti (HOC-Ti) was prepared via powder metallurgy. Its composition and mechanical properties were then characterized. After surface treatment by sandblasting and acid etching (SLA), the surface morphology, wettability and roughness of the HOC-Ti and CP-Ti sample were examined. In an in vitro test that followed an evaluation of the protein adsorption capacity of HOC-Ti, the mouse preosteoblast cells were inoculated onto the specimens to evaluate their biocompatibility, in comparison with those of CP-Ti. The oxygen concentration of the HOC-Ti increased to 0.62 wt%, which is higher than the 0.26 wt% of the CP-Ti, while their compositions and microstructures were very similar. The tensile and compressive yield strength of the HOC-Ti (800 MPa) was improved significantly in comparison to that of the CP-Ti (530 MPa). After surface treatment, a unique structure of micropores with a diameter of 380 nm was observed on the entire surface of the HOC-Ti that facilitates cell adhesion and proliferation. The wettability of the HOC-Ti was obviously superior (p < 0.05). The in vitro study showed that the MC3T3-E1 cells inoculated on the surface of HOC-Ti exhibited a homogeneous microstructure, and the viability was higher than that of the control group on days 4 and 7 (p < 0.05). In addition, the number and differentiation activity of cells that adhered to the surface of the HOC-Ti increased significantly on day 7 (p < 0.05). The experimental results showed that, in view of its mechanical properties and biocompatibility, HOC-Ti is superior to CP-Ti and is promising for oral implant applications.

Synthesis of Al2Ca Dispersoids by Powder Metallurgy Using a Mg-Al Alloy and CaO Particles.

The elemental mixture of Mg-6 wt %Al-1 wt %Zn-0.3 wt %Mn (AZ61B) alloy powder and CaO particles was consolidated by an equal-channel angular bulk mechanical alloying (ECABMA) process to form a composite precursor. Subsequently, the precursor was subjected to a heat treatment to synthesize fine Al2Ca particles via a solid-state reaction between the Mg-Al matrix and CaO additives. Scanning electron microscopy-energy-dispersive spectroscopy (SEM-EDS) and electron probe micro-analysis on the precursor indicated that 4.7-at % Al atoms formed a supersaturated solid solution in the α-Mg matrix. Transmission electron microscopy-EDS and X-ray diffraction analyses on the AZ61B composite precursor with 10-vol % CaO particles obtained by heat treatment confirmed that CaO additives were thermally decomposed in the Mg-Al alloy, and the solid-soluted Ca atoms diffused along the α-Mg grain boundaries. Al atoms also diffused to the grain boundaries because of attraction to the Ca atoms resulting from a strong reactivity between Al and Ca. As a result, needle-like (Mg,Al)2Ca intermetallics were formed as intermediate precipitates in the initial reaction stage during the heat treatment. Finally, the precipitates were transformed into spherical Al2Ca particles by the substitution of Al atoms for Mg atoms in (Mg,Al)2Ca after a long heat treatment.

Serum Metabolomic Profiles for Human Pancreatic Cancer Discrimination.

This study evaluated the clinical use of serum metabolomics to discriminate malignant cancers including pancreatic cancer (PC) from malignant diseases, such as biliary tract cancer (BTC), intraductal papillary mucinous carcinoma (IPMC), and various benign pancreaticobiliary diseases. Capillary electrophoresismass spectrometry was used to analyze charged metabolites. We repeatedly analyzed serum samples (n = 41) of different storage durations to identify metabolites showing high quantitative reproducibility, and subsequently analyzed all samples (n = 140). Overall, 189 metabolites were quantified and 66 metabolites had a 20% coefficient of variation and, of these, 24 metabolites showed significant differences among control, benign, and malignant groups (p < 0.05; Steel-Dwass test). Four multiple logistic regression models (MLR) were developed and one MLR model clearly discriminated all disease patients from healthy controls with an area under receiver operating characteristic curve (AUC) of 0.970 (95% confidential interval (CI), 0.946-0.994, p < 0.0001). Another model to discriminate PC from BTC and IPMC yielded AUC = 0.831 (95% CI, 0.650-1.01, p = 0.0020) with higher accuracy compared with tumor markers including carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9), pancreatic cancer-associated antigen (DUPAN2) and s-pancreas-1 antigen (SPAN1). Changes in metabolomic profiles might be used to screen for malignant cancers as well as to differentiate between PC and other malignant diseases.

Effectiveness of contrast-enhanced endoscopic ultrasound for detecting mural nodules in intraductal papillary mucinous neoplasm of the pancreas and for making therapeutic decisions.

BACKGROUND AND OBJECTIVES: There have been few studies to date evaluating the effectiveness of contrast-enhanced endoscopic ultrasound (CE-EUS) for detecting mural nodules in patients with branch duct-type intraductal papillary mucinous neoplasm (BD-IPMN) of the pancreas. We aim to evaluate the effectiveness of CE-EUS for detecting mural nodules in BD-IPMN. PATIENTS AND METHODS: Of the 427 BD-IPMN patients, 21 patients (4.9%) in whom the presence of mural nodules was suggested by CE computed tomography (CT) or magnetic resonance imaging (MRI), or in whom the presence of nodule-like lesions as shown by fundamental EUS, were examined by CE-EUS. RESULTS: The mean diameter of cystic lesions was 29.8 ± 12.8 mm. The mean diameter of mural nodules was 9.5 ± 5.7 mm. BD-IPMN was detected in the pancreatic head in 16 cases, pancreatic body in 2 cases, and pancreatic tail in 3 cases. The mean follow-up period was 17.2 ± 11.9 months. The detection rates of mural nodule-like lesions in BD-IPMN patients on CT, MRI, and fundamental EUS were 36.8%, 63.2%, and 100%, respectively. The detection rates of true mural nodules in BD-IPMN patients on CT, MRI, and fundamental EUS were 85.7%, 71.4%, and 100%, respectively. The echo levels of mural nodule-like lesions on fundamental EUS were hyperechoic in 6 patients, isoechoic in 9 patients, and hypoechoic in 6 patients. The final diagnosis was mucus lumps in 14 patients and mural nodules in 7 patients. The contrast patterns observed were avascular, isovascular, and hypervascular in 14, 3, and 4 patients, respectively. No patients showed a hypovascular pattern. Fourteen patients showing an avascular pattern were diagnosed as having mucus lumps, and they were able to avoid surgical resection. Of the 7 patients who were diagnosed as having mural nodules, 5 underwent surgical resection. The pathological findings were adenocarcinoma in 2 patients and adenoma in 3 patients. Of the 3 adenoma patients, fundamental EUS demonstrated a hypoechoic area in 1 patient and an isoechoic area in 2 patients. Of the 2 adenocarcinoma patients, 1 each showed a hypoechoic area and a hyperechoic area. It was difficult to distinguish between patients with adenoma and patients with adenocarcinoma using the echo levels obtained from fundamental EUS. CONCLUSIONS: CE-EUS may be useful for avoiding the overdiagnosis of BD-IPMN with mural nodule-like lesions. However, it has difficulty in distinguishing between clearly benign and malignant lesions in BD-IPMN.

Corrosion Behavior and Strength of Dissimilar Bonding Material between Ti and Mg Alloys Fabricated by Spark Plasma Sintering.

Ti and solution treated Mg alloys such as AZ31B (ST), AZ61 (ST), AZ80 (ST) and AZ91 (ST) were successfully bonded at 475 °C by spark plasma sintering, which is a promising new method in welding field. The formation of Ti3Al intermetallic compound was found to be an important factor in controlling the bonding strength and galvanic corrosion resistance of dissimilar materials. The maximum bonding strength and bonding efficiency at 193 MPa and 96% were obtained from Ti/AZ91 (ST), in which a thick and uniform nano-level Ti3Al layer was observed. This sample also shows the highest galvanic corrosion resistance with a measured galvanic width and depth of 281 and 19 µm, respectively. The corrosion resistance of the matrix on Mg alloy side was controlled by its Al content. AZ91 (ST) exhibited the highest corrosion resistance considered from its corrode surface after corrosion test in Kroll's etchant. The effect of Al content in Mg alloy on bonding strength and corrosion behavior of Ti/Mg alloy (ST) dissimilar materials is discussed in this work.

Multicenter, prospective, crossover trial comparing the door-knocking method with the conventional method for EUS-FNA of solid pancreatic masses (with videos).

BACKGROUND AND AIMS: There are currently no prospective, controlled trials of needle puncture speed in EUS-guided FNA (EUS-FNA). In this study, we prospectively evaluated the accuracy of histological diagnosis and the tissue acquisition rate of EUS-FNA by using the door-knocking method (DKM) with a standard 22-gauge needle. METHODS: From November 2013 to August 2014, 82 patients who had solid pancreatic masses underwent EUS-FNA in which the conventional method (CM) and DKM with 2 respective passes in turn were used. The primary outcomes of this study were the accuracy of histological diagnosis and the rates of tissue acquisition in 2 FNA procedures by using these 2 methods. RESULTS: Although the successful tissue acquisition rate for histology was not significantly different with the DKM and CM (91.5% vs 89.0%, P = .37), the high cellularity tissue acquisition rate for histology with the DKM was significantly superior to that with the CM (54.9% vs 41.5%, P = .03). However, adequate quality rate and accuracy were not different in the DKM and CM (78.0% vs 80.5%, P = .42 and 76.8% vs 78.0%, P = .50, respectively). In the transgastric puncture group, although the adequate quality rate and accuracy were similar in the DKM and CM (84.1% vs 79.4%, P = .30 and 84.1% vs 76.2%, P = .11, respectively), the tissue acquisition rate tended to be higher with the DKM than the CM (93.7% vs 85.7%, P = .06). Moreover, the high cellularity tissue acquisition rate was significantly better with the DKM than the CM (63.5% vs 39.7%, P = .002). On the other hand, in the transduodenal puncture group, although the tissue acquisition rate was similar with the DKM and CM (84.2% vs 100%, P = .13), the adequate quality rate and accuracy were significantly lower with the DKM than with the CM (57.9% vs 84.2%, P = .03 and 52.6% vs 84.2%, P = .02, respectively). CONCLUSION: EUS-FNA by using a 22-gauge needle with the DKM did not improve the accuracy of histological diagnosis, but enabled acquisition of a larger amount of tissue specimen by using transgastric puncture. ( TRIAL REGISTRATION: http://www.umin.ac.jp/english/: UMIN000012127.).

Balloon enteroscopy-assisted ERCP in patients with Roux-en-Y gastrectomy and intact papillae (with videos).

BACKGROUND AND AIMS: Balloon enteroscopy-assisted ERCP has provided a marked improvement in the success rate of reaching the papilla and consecutive ERCP procedures in patients with surgically altered anatomy in the Roux-en-Y reconstruction setting. However, limited data are available on the outcome of balloon enteroscopy-assisted ERCP in patients with Roux-en-Y anatomy who have naïve papillae. We retrospectively evaluated the feasibility of balloon enteroscopy-assisted ERCP in Roux-en-Y reconstruction after total or subtotal gastrectomy (RYG) with native papillae. METHODS: We performed 123 ERCP procedures in 109 patients with RYG. Among these patients, 90 consecutive ERCPs in 90 patients with native papillae were included. When selective biliary cannulation failed, the double-guidewire technique, the precut technique, or the rendezvous technique were performed as advanced cannulation methods. RESULTS: The overall success rate of reaching the papilla was 93.5% (115/123). The total procedure success rate was 88.1% (96/109). The adverse event rate was 7.3% (8/109). The success rate of the standard cannulation of the intact papilla was 67.8% (61/90). The final cannulation success rate was 95.6% (86/90) by using advanced cannulation methods. CONCLUSIONS: Standard cannulation of the intact papilla in RYG cases remains challenging and uncertain. The use of various advanced cannulation methods improves the deep cannulation rate. Once selective cannulation succeeds, the treatment success rate is very high.

Current status of preoperative biliary drainage.

Preoperative biliary drainage (PBD) has been thought to be preferable regardless of the site of biliary strictures, e.g., distal or proximal strictures because PBD by endoscopy or interventional radiology decreases postoperative mortality and morbidity rates. However, recently, several studies have revealed that PBD strategy showed an increased mortality rate or a high frequency of surgical site infection. Herein, we reviewed reports in the literature regarding the current status of PBD and investigated the effects of PBD on patients with distal and proximal biliary obstructions due to potentially resectable pancreatobiliary cancers. Our summary demonstrated that there is as yet no optimal PBD method regardless of the distal and proximal biliary strictures because of the small sample size and the lack of better control groups in previous studies. Thus, prospective randomized studies with a large sample size are needed to establish the optimal mode of PBD and to evaluate the potential benefits of PBD in patients with both distal and proximal biliary obstructions.

A newly designed plastic stent for EUS-guided hepaticogastrostomy: a prospective preliminary feasibility study (with videos).

BACKGROUND: There are currently no dedicated plastic stents for EUS-guided hepaticogastrostomy (EUS-HGS). OBJECTIVE: We prospectively evaluated the feasibility and the technical and functional success rates of our newly designed plastic stent for EUS-HGS. DESIGN: Prospective preliminary feasibility study. SETTING: A tertiary-care referral center. PATIENTS: Twenty-three consecutive patients were treated. The reasons for requiring EUS-HGS were periampullary tumor invasion (n=9), altered anatomy (n=7), failed duodenal intubation (n=3), and previous ERCP failure (n=4). INTERVENTIONS: An 8F single-pigtail plastic stent with 4 flanges was placed for EUS-HGS. MAIN OUTCOME MEASUREMENTS: Technical success, clinical success, and adverse events according to the American Society for Gastrointestinal Endoscopy lexicon. RESULTS: All stents were successfully deployed without procedural adverse events (100% technical success rate). Bleeding from the punctured gastric wall occurred in 1 patient 3 days postoperatively. We exchanged the plastic stent for a fully covered self-expandable metal stent. A mild adverse event of self-limited abdominal pain occurred in 3 patients. Treatment success was achieved in all patients. The occlusion rate was 13.7% (3/22) during the median follow-up period (5.0 months, range 0.5-12.5 months). The median duration of stent patency was 4.0 months (range 0.5-9.0 months). There was no stent migration or dislocation during the follow-up period. LIMITATIONS: Small number of patients and lack of a control group. CONCLUSIONS: This newly designed single-pigtail plastic stent dedicated for EUS-HGS was technically feasible and can possibly be used for highly selected patients with advanced malignancy or benign stricture. ( TRIAL REGISTRATION: http://www.umin.ac.jp/english/: UMIN000012993.).

Effectiveness of the J-Tip Guidewire for Selective Biliary Cannulation Compared to Conventional Guidewires (The JANGLE Study).

BACKGROUND: Wire-guided cannulation has become a common biliary cannulation technique worldwide. Different guidewires with various tip shapes and materials have been reportedly used for wire-guided cannulation. However, there are apparently no studies reporting changes in the biliary cannulation rate according to the type of guidewire used. AIMS: We evaluated the effectiveness of the J-tip guidewire for biliary cannulation. METHODS: We conducted a prospective, multicenter, controlled study involving patients with a native papilla who required biliary cannulation. We allocated the patients to the J-tip guidewire or angled-tip guidewire groups (groups J and A, respectively). If biliary cannulation was not achieved within 10 min, the GW was changed and cannulation was continued. RESULTS: Groups J and A consisted of 66 and 65 enrolled patients, respectively. The biliary cannulation rate with a single guidewire for the first 10 min was 84.8 % (56/66) for group J and 80.0 % (52/65) for group A. The final success rate for biliary cannulation was 100 % in both groups. The mean times necessary for biliary cannulation were 285.8 and 267.6 s in group J and group A, respectively. The incidence rates of complications (i.e., all mild pancreatitis) were 3.0 % (2/66) and 6.2 % (4/65) in group J and group A, respectively. The mean amylase concentrations were 168.0 and 297.7 IU/L in group J and group A, respectively. There were no significant differences in any results between both groups. CONCLUSION: The biliary cannulation rate of the J-tip guidewire was not significantly different from those of standard guidewires.

EUS-guided drainage of hepatic abscess and infected biloma using short and long metal stents (with videos).

BACKGROUND: Currently, few reports exist on EUS-guided hepatic abscess drainage (EUS-HAD) and EUS-guided biloma drainage (EUS-BLD) using a metal stent. OBJECTIVE: We evaluated the technical success rate and efficacy of EUS-HAD and EUS-BLD for patients with hepatic abscess (HA) and infected biloma. DESIGN: Retrospective case series. SETTING: Single tertiary referral medical center. PATIENTS: We evaluated 7 HA and 6 infected biloma patients who were treated between August 2013 and August 2014 at Tokyo Medical University Hospital. INTERVENTIONS: EUS-HAD or EUS-BLD using a short (length, 2 or 3 cm) or long (length, 6 or 8 cm) self-expandable fully covered metal stent. MAIN OUTCOME MEASUREMENTS: Technical success, clinical success, and adverse event. RESULTS: The overall technical success rate was 100% in both EUS-HAD and EUS-BLD. The clinical success rates of EUS-HAD and EUS-BLD at the first session were 71.4% and 83.3%, respectively. Direct endoscopic necrosectomy was required in 1 case each of HA and infected biloma. The final clinical success rate was 100%. There were no procedure-related adverse events or cases of recurrence during the follow-up period (median, 83.5 days; range, 24-396 days). LIMITATIONS: Small sample size and no control group. CONCLUSIONS: EUS-HAD and EUS-BLD using a metal stent can be performed safely and effectively for HA and infected biloma.

Initial evaluation of a new plastic pancreatic duct stent for endoscopic ultrasonography-guided placement.

There are currently no plastic pancreatic duct stents that have been designed for endoscopic ultrasonography (EUS)-guided placement. This study prospectively evaluated the feasibility and efficacy of a new, single-pigtail, plastic stent. Eight patients with main pancreatic duct stricture or stenotic pancreatojejunostomy underwent EUS-guided placement of the pancreatic duct stent. The stent was placed successfully in all cases (8/8). Treatment success was achieved in all cases (8/8). A mild adverse event associated with the procedure was observed in one patient but there were no other adverse events during a mean follow-up of 7.4 months. This new pancreatic duct stent appears to be feasible and effective for EUS-guided stenting.

Current status and perspective of endoscopic ultrasonography-guided gastrojejunostomy: endoscopic ultrasonography-guided double-balloon-occluded gastrojejunostomy (with videos).

Surgical intervention and, more recently, endoscopic intervention have been performed for the treatment of malignant gastric outlet obstruction. Recently, endoscopic ultrasonography (EUS)-guided gastrojejunostomy using special devices has been established. In line with this, we have developed a novel EUS-guided double-balloon-occluded gastrojejunostomy (EBOG) using a lumen-apposing biflanged metal stent. Herein, we describe the technique and outcome of EBOG.

Inter-wall bridging induced peeling of multi-walled carbon nanotubes during tensile failure in aluminum matrix composites.

In situ scanning electron microscopy (SEM) observation of a tensile test was performed to investigate the fracturing behavior of multi-walled carbon nanotubes (MWCNTs) in powder metallurgy Al matrix composites. A multiple peeling phenomenon during MWCNT fracturing was clearly observed. Its formation mechanism and resultant effect on the composite strength were examined. Through transition electron microscopy characterizations, it was observed that defective structures like inter-wall bridges cross-linked adjacent walls of MWCNTs. This structure was helpful to improve the inter-wall bonding conditions, leading to the effective load transfer between walls and resultant peeling behaviors of MWCNTs. These results might provide new understandings of the fracturing mechanisms of carbon nanotube reinforcements for designing high-performance nanocomposites.

Endoscopic ultrasound-guided placement of plastic vs. biflanged metal stents for therapy of walled-off necrosis: a retrospective single-center series.

BACKGROUND AND STUDY AIMS: Recently, a novel fully covered and biflanged metal stent (BFMS)dedicated to the drainage of walled-off necrosis(WON) was developed. The aim of this study was to retrospectively evaluate the safety, efficacy, and cost performance of drainage of WON using the novel BFMS compared with a traditional plastic stent. PATIENTS AND METHODS: A total of 70 patients with symptomatic WON were treated under endoscopic ultrasound (EUS) guidance. Initial drainage was conducted using the single gateway technique with placement of one or more plastic stents or a single BFMS.If drainage was unsuccessful,direct endoscopic necrosectomy (DEN)was performed. RESULTS: There were no statistically significant differences in rates of technical success, clinical success,and adverse events between plastics stents and BFMS, despite the size of WON in the BFMS group being significantly larger than that in the plastic stent group (105.6 vs. 77.1 mm; P=0.003).The mean procedure times for the first EUS-guided drainage and for re-intervention were significantly shorter in the BFMS group than in the plastic stent group (28.8±7.1 vs. 42.6±14.2, respectively,for drainage, P<0.001; and 34.9±8.5 vs.41.8±7.6, respectively, for re-intervention, P<0.001). There was no statistically significant difference in the total cost between plastic stent and BFMS use in the treatment of WON ($5352vs. $6274; P=0.25). CONCLUSIONS: Plastic stents and BFMS were safe and effective for the treatment of WON. In particular,BFMS placement appeared to be preferable for initial EUS-guided drainage and additional reintervention(e.g. DEN) as it reduced the procedure time. Prospective randomized controlled trials are warranted.