***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: OBJECTIVES Endoscopic necrosectomy is effective in the treatment of  walled-off necrosis ( WON )  , and is preferred to surgical approaches , however complication and mortality rates remain high with few centers regularly employing the technique . Lack of a st and ardized approach may also contribute to these limitations . METHODS Prior to the study , a multidisciplinary team applied st and ardized care assessment and management plan principles to develop and optimize a systematic approach for the management of WON . Preoperative , postoperative , and endoscopic management were st and ardized . Patient preparation , room set-up , technical features ( EUS-guidance , cold-access with balloon dilation , fragmentation of necrosis on the initial procedure , antibiotic lavage , double pigtail stents ) , and discontinuation of PPIs to encourage auto-digestion of necrosis were included . This study employed a consecutive prospect i ve clinical registry to assess the clinical outcomes of this st and ardized approach . RESULTS 60 consecutive patients underwent 1.58 ± 0.1 necrosectomies , with debridement accomplished on the initial procedure in 98.3 % . 39 patients ( 65 % ) required only one session . Clinical resolution occurred in 86.7 % , with radiologic confirmation . Percutaneous drainage was required in 8 patients during follow-up , and 4 of these later required surgery . Serious adverse events occurred in 3.3 % of patients , and there was no mortality . CONCLUSIONS The st and ardized technique employed in this series was associated with lower rates of adverse events , morbidity , and mortality than prior large series . Use of a systematic approach , and integrating elements of this method may improve the risk profile of endoscopic necrosectomy and allow broader adoption Aims . We attempted to establish some guidelines for the selection of transmural stents during endoscopic drainage of PFCs by retrospective review of the clinical data obtained from three tertiary hospitals . Patients and Methods . Clinical data of 93 patients with attempted endoscopic drainage of symptomatic PFCs were obtained through chart review and prospect i ve follow-up . Results . Treatment success for acute pseudocyst ( n = 67 ) , chronic pseudocyst ( n = 9 ) , and WOPN ( n = 17 ) was 95.3 % , 100 % , and 88.2 % , respectively ( P = 0.309 ) . Clinical success for single-stent drainage was 93.9 % ( 46/49 ) versus 97.4 % ( 37/38 ) for multiple-stent drainage ( P = 0.799 ) . Secondary infection for single-stent drainage was 18.4 % ( 9/49 ) versus 5.3 % ( 2/38 ) for multiple-stent drainage ( P = 0.134 ) . Secondary infection for stent diameter less than or equal to 8.5 F was 3.4 % ( 1/29 ) versus 17.2 % ( 10/58 ) for stent diameter larger than or equal to 10 F ( P = 0.138 ) . Conclusion . EUS-guided transmural drainage is an effective therapy for PFCs . Single-stent transmural drainage of PFCs is enough and does not seem to influence clinical success . The number or diameter of stents does not seem to be associated with secondary infection BACKGROUND Walled-off pancreatic necrosis often leads to severe clinical deterioration necessitating open debridement or endoscopic necrosectomy . A new EUS-based approach was devised to manage this condition by creating multiple transluminal gateways to facilitate effective drainage of the necrotic contents . OBJECTIVE To compare treatment outcomes between patients with walled-off pancreatic necrosis managed endoscopically by a multiple transluminal gateway technique ( MTGT ) or a conventional drainage technique ( CDT ) .  DESIGN Retrospective study . SETTING Tertiary-care referral center . PATIENTS This study involved patients with severe acute pancreatitis complicated by walled-off pancreatic necrosis managed endoscopically . INTERVENTION In MTGT , 2 or 3 transmural tracts were created by using EUS guidance between the necrotic cavity and the GI lumen . While one tract was used to flush normal saline solution via a nasocystic catheter , multiple stents were deployed in others to facilitate drainage of necrotic contents . In the CDT , two stents with a nasocystic catheter were deployed via 1 transmural tract . MAIN OUTCOME MEASUREMENTS Resolution of symptoms , radiological findings on follow-up CT , and the need for subsequent surgery or endoscopic necrosectomy . RESULTS Of 60 patients with symptomatic walled-off pancreatic necrosis , 12 ( 3 women , mean age 55.1 years ) were managed by MTGT and 48 ( 12 women , mean age 55.2 years ) by CDT .  Treatment was successful in 11 of 12 ( 91.7 % ) patients managed by MTGT versus 25 of 48 ( 52.1 % ) managed by CDT ( P = .01 ) . Although 1 patient in the MTGT cohort required endoscopic necrosectomy , in the CDT cohort , 17 required surgery , 3 underwent endoscopic necrosectomy , and 3 died of multiple-organ failure . Treatment success was more likely for patients treated by MTGT than by CDT ( adjusted odds ratio = 9.24 ; 95 % confidence interval , 1.08 - 79.02 ; P = .04 ) when we adjusted for the size of the walled-off pancreatic necrosis and pancreatic duct stent placement . LIMITATIONS Selective patient population . CONCLUSION The EUS-guided MTGT is an effective treatment option for the management of symptomatic walled-off pancreatic necrosis because it obviates the need for surgery and endoscopic necrosectomy and its attendant procedure-related morbidity . Prospect i ve studies are required to confirm these preliminary but promising data BACKGROUND Direct endoscopic necrosectomy ( DEN ) for treatment of walled-off pancreatic necrosis ( WOPN ) has been performed as an alternative to operative or percutaneous therapy . OBJECTIVE To report the largest combined experience of DEN performed for WOPN . DESIGN Retrospective chart review . SETTING Six U.S. tertiary medical centers . PATIENTS A total of 104 patients with a history of acute pancreatitis and symptomatic WOPN since 2003 . INTERVENTIONS DEN for WOPN . MAIN OUTCOME MEASUREMENTS Resolution or near-resolution of WOPN without the need for surgical or percutaneous intervention and procedural complications . RESULTS Successful resolution was achieved in 95 of 104 patients ( 91 % ) . Of the patients in whom it failed , 5 died during follow-up before resolution , 2 underwent operative drainage for persistent WOPN , 1 required surgery for massive bleeding on fistula tract dilation , and 1 died periprocedurally . The mean time to resolution from the initial DEN was 4.1 months . The first débridement was performed a mean of 63 days after the initial onset of acute pancreatitis . In 73 % , the entry was transgastric with median tract dilation diameter of 18 mm . The median number of procedures was 3 with 2 débridements . Complications occurred in approximately 14 % and included 5 retrogastric perforations/pneumoperitoneum , which were managed nonoperatively . Univariate analysis identified a body mass index > 32 as a risk factor for failed DEN . LIMITATIONS Retrospective , highly specialized centers . CONCLUSIONS This large , multicenter series demonstrates that transmural , minimally invasive endoscopic débridement of WOPN performed in the United States is an efficacious and reproducible technique with an acceptable safety profile Objectives Infected walled-off pancreatic necrosis ( WOPN ) is a complication of acute pancreatitis requiring intervention . Surgery is associated with considerable morbidity . Percutaneous catheter drainage ( PCD ) , initial therapy in the step-up approach , minimizes complications . Direct endoscopic necrosectomy ( DEN ) has demonstrated safety and efficacy . We compared outcome and health care utilization of DEN versus step-up approach . Methods This was a matched cohort study using a prospect i ve registry . Twelve consecutive DEN patients were matched with 12 step-up approach patients . Outcomes were clinical resolution after primary therapeutic modality , new organ failure , mortality , endocrine or exocrine insufficiency , length of stay , and health care utilization . Results Clinical resolution in 11 of 12 patients after DEN versus 3 of 12 step-up approach patients after PCD ( P < 0.01 ) . Nine step-up approach patients required surgery ; 7 of these experienced complications . Direct endoscopic necrosectomy result ed in less new antibiotic use , pulmonary failure , endocrine insufficiency , and shorter length of stay ( P < 0.05 ) . Health care utilization was lower after DEN by 5.2:1 ( P < 0.01 ) . Conclusions Direct endoscopic necrosectomy may be superior to step-up approach for WOPN with suspected or established infection . Primary PCD generally delayed definitive therapy . Given the higher efficacy , shorter length of stay , and lower health care utilization , DEN could be the first-line therapy for WOPN , with primary PCD for inaccessible or immature collection 
    Output:
    
Evidence suggests that MSs are superior for WON resolution , with fewer bleeding events , trend toward less occlusion and perforation rate , but increased migration rate compared with PSs