INTRODUCTION

Endoscopic management by endoscopic ultrasound(EUS)-guided drainage and endoscopic necrosectomy has become the preferred treatment of walled-off pancreatic necrosis (WOPN) after necrotizing pancreatitis as it is minimally invasive and has lower morbidity compared to surgery[1,2]. Pancreatic pseudocysts can be relatively easily drained by insertion of plastic stents but the drainage of WOPN requires large caliber drainage or multi-stenting to empty the necrotic debris and often the remaining necrotic material has to be extracted by endoscopic necrosectomy[3-5]. The use of conventional plastic stents has limitations when treating WOPN because their narrow lumen is often prematurely occluded by necrotic debris[3].

（2）在财务报销方面，虽然差旅费和培训费、会议费文件众多，但文件间口径不统一，使用时感觉模棱两可；外出活动通知有时候没有明确是会议还是培训，致使财务人员无法判断该适用什么文件去计算补贴；票据方面，组织单位往往开具文件规定范围外的票据，比如培训时出具往来款收据，在老师回单位报销时，财务人员碍于情面或疏忽大意予以了支付，这就造成教育资金的不当支出。

The development of large caliber, specially designed lumen apposing fully covered self-expanding metal stents (FCSEMS) has provided new options for the drainage of peripancreatic fl uid collections and improved clinical outcome[4-7].

Previously Rana et al[8] demonstrated that transmural drainage of non-bulging WOPN using plastic stents and nasocystic drains can be safely and effectively achieved non- fl uoroscopically by endoscopic ultrasound guidance.The EUS-visibility during EUS-guided placement of metal stents has not been studied previously. However,the avoidance of radiation exposure and fluoroscopy would improve the availability of this outcome changing procedure for critically ill patients as it could be performed at the bedside.

Therefore, in this two-center, single arm study we investigated whether the transmural insertion of FCSEMS for large caliber drainage of WOPN is safely possible by EUS guidance only, avoiding fluoroscopy.For this purpose, we aimed to assess the EUS-visibility of all procedural steps that are required for EUS-guided transmural insertion of FCSEMS.

MATERIALS AND METHODS

From May 2014 we started a prospectively maintained database to audit clinical outcome of EUS-guided therapy of pancreatic fluid collections. EUS-guided transmural drainage of walled-off necrosis by FCSEMS insertion performed between May 2014 and August 2017 were analysed. Participating centers were the John Radcliffe Hospital in Oxford, United Kingdom and the Caritas Hospital in Bad Mergentheim, Germany.

当然，这都是比较低级小儿科的方式，这位人士还透露，更高层次往往是参股外部公司的方式，这种方式更隐蔽，甚至披上了合法的外衣。

射流原理如图1所示。当流体Q1在v1的高速下进入特殊形状容腔，会在容腔喉部(a处)形成负压，对周围流体形成抽吸作用，最终携带被吸入的流体Q2以v2的速度混合成流体Q3从出口流出。a处负压越大，射流效果越好。

The observational nature of the study was established with the respective Health Research Authority and Trust R and D department. The study was therefore registered locally in accordance with Trust clinical governance guidelines. All authors had access to the study data and had reviewed and approved the final manuscript.

Patients underwent EUS-guided FCSEMS insertion only if computed tomography or MRCP had con firmed WOPN based on the revised Atlanta classification[9] and the patients were symptomatic due to gastric outlet obstruction or biliary obstruction, or ongoing infection and fever despite intravenous antibiotic therapy. EUS-guided transluminal drainage of the pancreatic collection was performed at least four weeks after onset of pancreatitis to allow for sufficient demarcation of the necrotic tissue. Patients were informed in detail about the risks and bene fits of the endoscopic treatment and surgical and endoscopic alternatives. Informed consent was obtained from all patients before the endoscopic procedure.

Using a linear scanning therapeutic echoendoscope(EG 3870 Pentax Inc., Tokyo, Japan) EUS-guided drainage was performed in the endoscopy unit under endotracheal intubation and monitoring by an anaesthetic team. Doppler guidance was used to avoid intervening blood vessels and the optimal site for transmural access was selected giving the closest distance between necrotic fluid collection and the gastroduodenal lumen.Transmural access into the WOPN was achieved using a cystotome (Cook Endoscopy, Winston-Salem, NC, United States) or directly the Hot AxiosTM electrocautery system(Xlumena Inc., Mountain View, CA, United States).

A 0.035-inch guidewire was advanced under EUS-guidance and coiled at least twice into the cavity to stabilize the position. The new tract was enlarged using the diathermy of the cystotome or the AxiosTM electrocautery system before the stent delivery system(AxiosTM or NAGITM stent, TaeWoong Medical, Gyeonggido, South Korea) was introduced over the guidewire.For correct positioning, the opening of the distal fl ange in the cavity and slow withdrawal of the entire delivery system until the distal flange was in contact with the wall was controlled by EUS while the opening of the proximal fl ange was then observed endoscopically.

The EUS visibility of each step involved in the transmural stent insertion was assessed by the operators as “visible” or “not visible”: (1) Access to the cyst by needle or cystotome; (2) insertion of a guide wire; (3)introducing of the diathermy and delivery system; (4)opening of the distal flange; and (5) slow withdrawal until contact of distal fl ange to cavity wall.

Final correct position of the FCSEMS was con firmed endoscopically when the liquid content of the WOPN emptied through the stent into the gastric lumen.Fluoroscopy was not used at any time during the procedure.

As clinically indicated, endoscopic necrosectomy was performed through the large diameter metal stent[10].When the collection had shrunk to less than 4 cm on ultrasound or computed tomography after at least 6 wk follow-up the metal stent was endoscopically removed.Additional pigtail plastic stents were not inserted during this study, neither through the FCSEMS to prevent stent migration nor after removal of the FCSEMS.

Further imaging after stent removal was reviewed to assess recurrence of pancreatic collections.

Primary outcome of this study was the technical feasibility of EUS-guided FCSEMS placement without fl uoroscopy and the EUS visibility of the different steps during stent insertion. Technical success was defined as correct positioning of the transmural FCEMS without using fluoroscopy during the procedure. Secondary outcome parameters included adverse events and clinical outcome.

Statistical analysis

Informed consent statement: Informed consent was obtained from all patients.

我们知道现实总是与虚拟相对的，自然而然地，实体经济也是与虚拟经济相对的一个概念。在多数中国人的理解中，实体经济就是将实物的经济资本当作对象进行投资与运营的一系列经济活动。20世纪末，我国的成思危教授开始对实体经济这个概念进行深入的探索与研究，从成教授的研究结果中可以得出这样一个结论，实体经济把物质资料作为基础和媒介，集物料的生产、分配、交换和消费等诸多经济活动为一体。之后的许多经济学者也都对实体经济进行过深入的分析讨论，习近平总书记和李克强总理也先后就实体经济发表过讲话。

RESULTS

From the prospective database, 27 consecutive patients with symptomatic walled-off necrosis after necrotizing pancreatitis were identified who were referred for EUS-guided insertion of FCSEMS to drain the fl uid content and necrotic debris. Patient demographics and indications for endoscopic intervention are given in Table 1.

性诱剂的主要组成部分是诱芯和诱捕器。每个诱捕器需至少配置一枚诱芯，对害虫能起到一定的诱导作用，即通过模拟雌性害虫所散发出的一种可引诱雄性害虫前来交尾的微量化学物质。当性诱剂引诱到大批量的雄性害虫后，从源头上遏制了害虫的数量[3]。

Technical feasibility

In 2 patients large diameter traversing arteries within the cavity were detected by Doppler during the orientating EUS, therefore the insertion of FCSEMS was not attempted to avoid possible erosion of the vessels by the stent edges with reducing collection size. In one patient a plastic stent was inserted instead, the other suffered a spontaneous haemorrhage into the necrotic cavity a week later and was found to have a necrotic tumour at surgery.

In all other patients, the EUS-guided insertion of the FCSEMS was technically successful achieving correct stent positioning without any fl uoroscopy (92.6%) (Table 2).

EUS visibility

(1) Access to the cyst by needle or cystotome could be endosonographically visualized in all 25 patients; (2)insertion of a guide wire could be monitored on EUS in all patients, however, the visibility of the entire coiling of the wire was limited in 6 patients with large amounts of debris within the cavity (＞ 30%); (3) introduction of the diathermy and delivery system was clearly seen,both in all NAGITM as well as all Hot AxiosTM stents. The diathermy produces artefacts on EUS during transmural transition but the caliber difference between guidewire and diathermy/delivery system is clearly visible within the fluid filled cavity; (4) opening of the distal flange could be clearly observed using all stents; and (5)the slow withdrawal of the opened distal flange until reaching contact to the cavity wall could be continuously monitored with both stent types in all patients (Figure 1).

Adverse events and clinical outcome

14 Anderloni A, Attili F, Carrara S, Galasso D, Di Leo M, Costamagna G, Repici A, Kunda R, Larghi A. Intra-channel stent release technique for fluoroless endoscopic ultrasound-guided lumenapposing metal stent placement: changing the paradigm. Endosc Int Open 2017; 5: E25-E29 [PMID: 28337480 DOI: 10.1055/s-0042-122009]

Overall procedure-related adverse events occurred in 3 of 25 patients (12.0%); one patient developed self-limiting bleeding, two patients were readmitted with fever and a blocked stent and subsequently underwent endoscopic necrosectomy. In one of the readmitted patients the stent migrated spontaneously after 4 wk but the WOPN had already resolved. There was no procedure-related mortality (Table 2).

After 8 wk the WOPN had resolved in all but one patient (96.0%) to a diameter of less than 4 cm. The patient with persistent WOPN had deep extensions of the inflammatory cavity into the retrocolic gutter requiring additional percutaneous drainage.

13 Itoi T, Binmoeller KF, Shah J, Sofuni A, Itokawa F, Kurihara T, Tsuchiya T, Ishii K, Tsuji S, Ikeuchi N, Moriyasu F. Clinical evaluation of a novel lumen-apposing metal stent for endosonography-guided pancreatic pseudocyst and gallbladder drainage (with videos). Gastrointest Endosc 2012; 75: 870-876 [PMID: 22301347 DOI: 10.1016/j.gie.2011.10.020]

There were no adverse events at the time of stent removal. From the 24 patients with successful resolution of the WOPN, 20 had further imaging (ultrasound, CT or MRCP) after six months. None had reoccurrence of pancreatic collections indicating disconnected pancreatic tail syndrome. Four patients did not have follow-up of more than 8 wk available as they had been discharged back to the referring hospitals.

DISCUSSION

The endoscopic management of WOPN has been simplified by technical advances in EUS and the development of specially designed, dumbbell-shaped, fully covered large caliber stents which can be placed endoscopically in a few or even only one step[5,11-13]. In contrast to plastic stents, the radial expansive forces of FCSEMS and the lumen-apposing design avoid leakage of fl uid along the newly created transmural tract. The wide fl anges should prevent dislodgment and migration.

Usually, FCSEMS are placed under EUS-guidance with fluoroscopic control of guidewire insertion, tract enlargement and stent deployment. In these series, we could show that all the steps required for endoscopic transmural insertion of FCSEMS into a WOPN can be visualized and safely monitored by EUS without the need for fl uoroscopy. Although we used different stents due to availability and preference in the different centres,the EUS visibility of both types during all steps of the procedure was excellent: The cystotome access, the insertion of the guidewire, the transmural advancing ofthe diathermy and delivery system, the opening of the distal fl ange and the correct positioning by withdrawal to the wall of the WOPN could be controlled and displayed by EUS in all patients.

On the other hand, the endosonographic visibility of access needle, guide-wire, cystotome and stent delivery system might depend on the debris content within the WOPN. None of the WOPNs in this series had debris of more than 50% but we only very rarely see WOPN with debris filling more than 50% of the cavity.

此外，在限幅机构与探测器一同飞行工作阶段以及钻取采样作业全工作过程中，限幅机构将受到随机的振动载荷以及钻具的横向负载：

Fluoroscopy has not been applied in any of the transgastric stent insertions in this study. It might be argued that the availability of fl uoroscopy is important should adverse events occur during the procedure.However, the most common complications related to EUS-guided transluminal stent insertion into pancreatic collections can be managed endoscopically or recognized endosonographically as well. In case of massive bleeding it might be helpful to in fl ate a balloon within the stent to achieve tamponade. Stent dislocation or incorrect positioning is recognized endoscopically and usually requires repeating the procedure.

Recently, an intra-channel release technique has been described for the hot axios stent which also enables a fluoroless placement[14]. However, it remains unclear whether fluoroscopy has been used additionally in these cases and the visibility of the deployment steps has not been reported. Another retrospective recent study reports on 25 selected patients in whom EUS-guided stent insertion was safely performed without fl uoroscopy[15].

The strength of our study is the fact that we included consecutive patients and systematically assessed the visibility of all procedure steps. Another advantage is that we tested the EUS-visibility of two types of stents,a lumen apposing and another FCSEMs, the most commonly inserted metal stents for the purpose of WOPN drainage.

综合以上结论，给予护士正确的社会支持，有利于降低护士的职业倦怠感和工作压力，可提升护士工作效率和积极性。社会利用度、社会支持和管理及人际关系、时间分配及工作量、职业倦怠感、护理专业工之间呈现出负相关性。

In nine patients endoscopic necrosectomy to extract obstructing necrotic material from the stent was required. The large diameter of the stents allows the direct endoscopic access and the anchoring flanges prevent stent dislodgment during the endoscopic debridement of the necrotic cavity.

For 20 patients imaging follow-up after 6 mo was available. None of these patients had signs of reoccurrence of a peripancreatic collection after removal of the FCSEMS as would be expected in case of disconnected pancreatic tail syndrome. The large diameter of the newly created track between pancreatic cavity and gastric lumen by the FCSEMS might facilitate persistence of a pancreaticogastric fistula if the pancreatic tail cannot drain via the papilla.

11 Walter D, Will U, Sanchez-Yague A, Brenke D, Hampe J, Wollny H, López-Jamar JM, Jechart G, Vilmann P, Gornals JB, Ullrich S, Fähndrich M, de Tejada AH, Junquera F, Gonzalez-Huix F,Siersema PD, Vleggaar FP. A novel lumen-apposing metal stent for endoscopic ultrasound-guided drainage of pancreatic fluid collections: a prospective cohort study. Endoscopy 2015; 47: 63-67[PMID: 25268308 DOI: 10.1055/s-0034-1378113]

Our study has some limitations. The endoscopists evaluated the visibility of the different procedure steps themselves during the intervention. The procedures were not recorded and images were not evaluated by a second person. Also, we are tertiary centers practicing advanced endoscopic ultrasound procedures and our results may not be replicated in other centers. However,we believe that patients with complex WOPN should be treated in expert centers with multidisciplinary teams and expertise in pancreatic surgery. In addition, our study was not randomized or controlled and the sample size was relatively small. Ideally, a larger randomized study with a control arm using EUS and fluoroscopic imaging should be conducted.

In conclusion, all procedural steps during EUS-guided insertion of FCSEMS are well visualized by EUS. Nonfl uoroscopic EUS-guided transmural insertion of FCSEMS for drainage of WOPN is feasible and appears to be safe and effective. Without the need for fluoroscopy and radiation exposure, EUS-guided drainage of WOPN with insertion of FCSEMS can become a bedside intervention for critically ill patients.

ARTICLE HIGHLIGHTS

Research background

Transluminal placement of specially designed fully covered self-expandable and lumen-apposing metal stents (FCSEMS) has improved the management and clinical outcome of walled-off pancreatic necrosis (WOPN). Most often this procedure is performed under fl uoroscopy after EUS-guided access.

俄罗斯认为俄罗斯是欧洲的俄罗斯，但是却注定漂泊。横跨欧亚的国土和以前蛮荒的历史让他之于亚洲、欧洲仿佛是禽鸟、野兽之间的蝙蝠。纵使它历史绵长，自认承拜占庭之正统；纵使它幅员辽阔，坐拥世界上最大的版图。

Research motivation

Without the need for fl uoroscopy EUS-guided drainage using large diameter metal stents would also become available in endoscopy units and at the bedside of critically ill patients. This procedure is often crucial for the management of patients with complex pancreatic necrosis.

Research objectives

The principal aim of this study is to assess the feasibility and safety of fl uoroless, purely EUS-guided insertion of self-expandable and lumen-apposing stents for the drainage of walled-off pancreatic necrosis.

Research methods

In 27 consecutive patients, we investigated the EUS-visibility of all procedural steps required to insert a fully covered self-expandable metal stent as transluminal drainage of walled-off pancreatic necrosis. EUS-visibility, technical success, outcome and adverse events were analysed.

Research results

All procedural steps could be visualised by EUS alone. Fluoroscopy was avoided in all patients undergoing transmural stent placement. EUS-guided insertion of the FCSEMS was technically successful achieving correct stent positioning in 92.6%.

Research conclusions

Institutional review board statement: After discussion with the local Ethics Service, they considered this observational project to be an audit rather than a research project, therefore ethical approval was not required.

Research perspectives

Large multi-center studies and prospective registries would provide more information on the use of EUS-guided WOPN drainage as bedside intervention,its safety and long-term outcome, the best time intervals when to remove the metal stents.

REFERENCES

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The sound of river flow is big at the early autumn, it would snow heavily in the course of whole autumn.

4 Vazquez-Sequeiros E, Baron TH, Pérez-Miranda M, Sánchez-Yagüe A, Gornals J, Gonzalez-Huix F, de la Serna C, Gonzalez Martin JA, Gimeno-Garcia AZ, Marra-Lopez C, Castellot A,Alberca F, Fernandez-Urien I, Aparicio JR, Legaz ML, Sendino O, Loras C, Subtil JC, Nerin J, Perez-Carreras M, Diaz-Tasende J, Perez G, Repiso A, Vilella A, Dolz C, Alvarez A, Rodriguez S,Esteban JM, Juzgado D, Albillos A; Spanish Group for FCSEMS in Pancreas Collections. Evaluation of the short- and longterm effectiveness and safety of fully covered self-expandable metal stents for drainage of pancreatic fluid collections: results of a Spanish nationwide registry. Gastrointest Endosc 2016; 84:450-457.e2 [PMID: 26970012 DOI: 10.1016/j.gie.2016.02.044]

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9 Banks PA, Bollen TL, Dervenis C, Gooszen HG, Johnson CD,Sarr MG, Tsiotos GG, Vege SS, Acute Pancreatitis Classification Working Group. Classification of acute pancreatitis-2012: revision of the Atlanta classification and definitions by international consensus 2013; 102-111

10 Seifert H, Wehrmann T, Schmitt T, Zeuzem S, Caspary WF.Retroperitoneal endoscopic debridement for infected peripancreatic necrosis. Lancet 2000; 356: 653-655 [PMID: 10968442 DOI:10.1016/S0140-6736(00)02611-8]

洪子诚先生认为“镜头”即诗的意象，从而对北岛早期诗歌中的意象群展开分析。他提出了两组基本的意象群。一个是作为理想世界、人道世界的象征物存在的，如天空、鲜花、红玫瑰、橘子、土地、野百合等。另一个带有否定色彩和批判意味，如网，生锈的铁栅栏，颓败的墙，破败的古寺等，“表示对人的正常的、人性的生活的破坏、阻隔，对人的自由精神的禁锢。”[5]北岛早期的诗意象的涵义过于确定。到了《触电》这里，我们会发现其意象的设置与北岛早期诗歌有明显的不同。《触电》中的意象，如“握手”，所指不明，与日常生活和传统意象都有距离和阻隔，只给读者一模糊的感知，却难以找到词语明确地与之对应。

整备质量(kg) .......................................1665

12 Binmoeller KF, Shah J. A novel lumen-apposing stent for transluminal drainage of nonadherent extraintestinal fluid collections. Endoscopy 2011; 43: 337-342 [PMID: 21264800 DOI:10.1055/s-0030-1256127]

为提高充电连续性和可靠性，本文所研究的基于波束成形的一对一无线充电流程如图2所示。增加了扫描、充电完成判断2个环节，并包含NS次扫描，以及扫描到接收端后允许的k次充电子过程。其中，NS≤NSmax，NSmax=2π/θ为波束扫描一周所需次数，θ为单波束角度；充电子过程包含4个环节：连接→读写数据→充电→充电完成判断，k≤K。本文中，令K=3[11]。

In nine patients, endoscopic necrosectomy through the large diameter metal stent became necessary due to incomplete clearance of debris or stent occlusion by obstructing necrotic tissue and/or infection.

15 Yoo J, Yan L, Hasan R, Somalya S, Nieto J, Siddiqui AA.Feasibility, safety, and outcomes of a single-step endoscopic ultrasonography-guided drainage of pancreatic fluid collections without fl uoroscopy using a novel electrocautery-enhanced lumenapposing, self-expanding metal stent. Endosc Ultrasound 2017; 6:131-135 [PMID: 28440239 DOI: 10.4103/2303-9027.204814]