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erforming Double-Balloonnteroscopy: The Utility of the Erlangen EndoTrainer

ndrea May, MD, PhD

Double-balloon enteroscopy (DBE) is now an established method for endoscopic visual-ization of the deep small bowel. DBE is not only a diagnostic tool, but also makes it possibleto take biopsy samples and perform endoscopic therapeutic interventions. However, DBEis a complex examination and should therefore only be performed by experienced endos-copists after appropriate training. The best method of teaching DBE and improving theacquisition of competence appears to be through step-by-step training. Lectures andvideos are very useful during the initial steps, whereas hands-on training with animalmodels and demonstration of live DBE procedures are the main components used forproviding training in and teaching of DBE. Ex vivo pig models, such as the modifiedErlangen EndoTrainer, are useful methods to teach DBE.Tech Gastrointest Endosc 10:54-58. © 2008 Published by Elsevier Inc.

KEYWORDS double balloon enteroscopy, skills, enteroscopy, endoscopy

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ouble-balloon enteroscopy (DBE) has become an estab-lished endoscopic examination method for both diag-

osis and treatment of suspected or known small-bowel dis-ases.1-5 As it is a complex examination method for which aonsiderable amount of endoscopic experience is a prerequi-ite, the questions arise of how the DBE technique can best beommunicated to users, how the learning curve can be pos-tively influenced, and how skills in DBE can be enhanced.

A step-by-step learning procedure must be regarded as usefulere (Fig. 1). The fundamental basis for carrying out DBE suc-essfully is familiarity with pathological findings in the smallowel, which can be very well illustrated using image and videoxamples and case studies. Equally important is communicatinghe technical basis for DBE, both with regard to the enteroscopesnd also the principle of the technique. The second step involveshe observation of live procedures in patients, conducted byxperienced DBE investigators, as well as hands-on training us-ng a fresh ex vivo model. The final step involves “one-on-one”raining with a senior endoscopist who is experienced in DBE.he first two learning stages are easily communicated in the

ramework of 1-day workshops.

orkshop Designixty national and international workshops, with a total of32 participants, have been conducted in Wiesbaden be-

epartment of Internal Medicine II, HSK Wiesbaden (Teaching Hospital ofthe University of Mainz), Wiesbaden, Germany.

ddress reprint requests to Andrea May, MD, PhD, Department of InternalMedicine II, HSK Wiesbaden, Ludwig-Erhard-Strasse 100, 65199 Wies-

nbaden, Germany. E-mail: ADinahMay@aol.com

4 1096-2883/08/$-see front matter © 2008 Published by Elsevier Inc.doi:10.1016/j.tgie.2007.12.004

ween January 2004 and June 2006. The workshops weretructured into 2 major parts, each of which was in turnubdivided into 3 parts. The workshops started with a lectureresenting general and technical data concerning DBE, asell as the results in comparison with other endoscopic mo-alities in the small bowel (eg, capsule endoscopy, push en-eroscopy, and intraoperative enteroscopy). This was fol-owed by a live examination of a patient with suspected ornown small-bowel disease, after which training withands-on enteroscopy using the Erlangen EndoTrainer wasrovided. After a break, further training with the Endo-rainer was possible if some of the course participants were

nterested in this. The course continued with a presentationnd discussion of interesting case reports, a report on expe-ience with DBE in Wiesbaden and in the published litera-ure, and a special section with tips and tricks—particularlyor therapeutic interventions with DBE—depending on thearticipants’ level of experience. After this, another live dem-nstration was performed. At the end of the workshop, thereas a further opportunity to discuss important points and

xchange experiences. Each participant receives a certificatet the end of the day.

rlangen EndoTrainerhe principle of DBE has been described in detail previ-usly1,2 and is illustrated in a simplified diagram in Figure. Although this enteroscopy technique appears to beuite simple, it is often hard to picture it in operation,specially at the beginning of the learning curve with the

ew technique. The development of an ex vivo model

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DBE and the Erlangen EndoTrainer 55

sing animal intestines has been a very important step ineaching DBE in this respect.

The model is based on the Erlangen EndoTrainer, whichas developed in 1992 for teaching upper gastrointestinal

ndoscopy and endoscopic retrograde cholangiopancreatog-aphy (ERCP).6-9 It consists of a human-shaped dummy andpecially prepared porcine upper visceral organ packages.he organ package is attached to the dummy using severalutures that are made immediately before the model is pre-ared for the training course. For the special conditionseeded in DBE, the model was modified, and the wholeuodenum and 150-200 cm of small bowel were pre-ared.9 The dummy’s anatomy is completed with a headroduced with synthetic material that allows realistic in-ertion of the enteroscope into the mouth and passagehrough the esophagus and stomach. For training in DBE,transparent ventral shell or open dummy was chosen to

llow visual orientation and visualization of the way inhich the small bowel is threaded onto the overtube dur-

ng the push-and-pull procedures (Fig. 3).This model is highly suitable for illustrating the princi-

le of DBE, including the associated stresses to which themall bowel is exposed due to the shearing and tractionorces exerted during the individual push-and-pull ma-euvers. It allows the anatomic features of the small bowelo be studied, and important points that need to be taken

Lectures, including video clips:

Pathological findings in the small bowel

Value of the endoscopic modalities

Technical background of the DBE device

Demonstration of live procedures by experienced DBE investigators

Hands-on training using an ex-vivo animal model

“One-on-one” training with a

senior DB endoscopist

Step 1

Step 2

Step 3

igure 1 Teaching of double-balloon endoscopy. (Color version ofgure is available at www.techgiendoscopy.com.)

Overtub

Overtuigure 2 Diagram illustrating the principle of double-alloon endoscopy. Yellow, a deflated balloon; or-nge, an inflated balloon. (Color version of figure isvailable at www.techgiendoscopy.com.)

nto account during DBE can be displayed in a veryraphic way, eg, the optimal positioning of the device inhe small bowel and the effect that air insufflation duringnteroscopy and the trapping of air between the small-owel folds has on the process of threading the smallowel onto the overtube. The model also allows hands-onraining, in which users can practice the sequences of in-ividual steps. Training in therapeutic interventions can ofourse also be provided with the model. The major disad-antage and limitation of this model is that it can be onlysed for training in the oral DBE procedure. The experi-nce of the Murcia group has been that the best way of

igure 3 In vitro animal model using a modified ErlangenndoTrainer.

Endoscope

Endoscope

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Overtube Endoscope

Overtube Endoscope

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56 A. May

roviding training with the anal route is to use a live dogodel (personal communication, Enrique Pérez-Cuadrado,urcia, Spain, at the 2nd International DBE Meeting, Berlin,ermany, June 16th, 2007).

utcomeseasurement of the

nsertion Depth during Enteroscopyhe ex vivo pig model described above was also used toalidate a method for measuring the insertion depth.hen the small bowel is being threaded onto the overtube

igure 4 Air trapping in the small bowel. (Color version of figure isvailable at www.techgiendoscopy.com.)

y means of repeated push-and-pull procedures (Fig. 2), its virtually impossible to be certain of the insertion depthf the enteroscope and to estimate the length of the smallowel that has been visualized, or to determine the loca-ion of any pathological findings without additional assis-ance. In contrast to conventional push enteroscopy, ra-iographic checking of the enteroscope’s position is notelpful for determining the depth of insertion, since in theptimal case, the repeated push-and-pull procedures al-ays create the same, or a similar, radiographic image, as

he loops that form during the push procedure resolveuring the pull procedure. Another method of measure-ent was therefore needed. The idea was that the depth of

nsertion of the endoscope into the small bowel can bestimated by recording the net advancement of the endo-cope for each push-and-pull maneuver on a standardizedocumentation sheet. At the end of the examination, or ifrelevant finding was seen, all of the figures recorded are

dded and the length of small bowel that has been visual-zed can be estimated. This method allows rough estima-ion of the insertion depth and an approximate location ofhe pathological findings seen during enteroscopy, andas been described in detail previously.6

peed and Depth of Insertionne of the most important points for fast and especially deep

nsertion is air insufflation during the DBE procedure. Thearger the amount of air that is insufflated during insertion ofhe endoscope and pulling back of the endoscope and thevertube, and the smaller the amount of air that is sucked outetween the individual steps of the push-and-pull maneu-

Figure 5 (A) Fluoroscopic imageof an optimal position for the oralroute. (B) Fluoroscopic image ofan optimal position for the analroute. (C) Fluoroscopic image ofcomplete enteroscopy using oraldouble-balloon endoscopy.

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DBE and the Erlangen EndoTrainer 57

ers, the greater the space that is needed on the overtube forhreading the small bowel (Fig. 4). Due to this air trapping,he overtube quickly becomes “full” of small bowel; no moremall bowel can be threaded onto the overtube, and the DBErocedure has to be stopped, independently of the depth of

nsertion achieved up to that point. This can be illustratedery clearly with the EndoTrainer model.

To reduce the amount of air insufflation needed when themall bowel is empty of air and liquid and “stuck together” inpatient, an injection of water combined with simethicone,

or example (to reduce bubble formation) can be recom-ended, as the small bowel opens up quickly after fluid

njection. The use of CO2 instead of air might also solve thisroblem in the future.The next point that has to be considered is the straight-

ning of the scope and resolving of loops formed duringnsertion of the scope and during pulling back of the scopend the overtube. The fewer the loops that have formed,he deeper the enteroscopy that can be expected, and com-lete enteroscopy may even be possible. This is easilyemonstrated thanks to the transparent ventral shell in thepen dummy. When patients are being examined, the usef fluoroscopic monitoring during the straightening pro-ess is helpful, especially at the start of the learning curvend in difficult situations, such as those caused by adhe-ions due to prior abdominal surgery. Figure 5 showsuoroscopic images of the optimal positions of the scope

or the oral and anal approaches and of a complete en-eroscopy with oral DBE.

Choosing the prone position for oral DBE leads to a certainmount of compression of the patient’s abdomen, which cane helpful during advancement, at least in patients with aormal or increased body mass index. In thin patients, thedditional use of a rigid pillow may be helpful.

In my own experience and opinion, the P-type scope (Fu-inon EN-450P5/20) is more useful for deep insertion or evenomplete enteroscopy during oral DBE, as the instrument isore flexible and robust than the thicker T-type (FujinonN-450T5).

nsertion of Accessorieshen the enteroscope is positioned deep in the small bowel,

t can sometimes be difficult to insert accessories, eg, thinrgon plasma coagulation probes or injection needles. Appli-ation of approximately 2 mL of silicone oil into the workinghannel just before using the accessories facilitates their ad-ancement. In the case of injection needles, it is very impor-ant to use needles with a stiff catheter and a sharp tip on theeedle. In addition, the endoscopist has to take care thathe tip of the enteroscope is not flexed too much and thathere are no small loops (Fig. 6). During teaching with thendoTrainer, these factors can easily be demonstrated with

he “open” small bowel. In the case of a DBE procedure in aatient, fluoroscopic monitoring is helpful for visualizing theroblem and changing the position of the enteroscope.

eaching Therapeuticnterventions with the EndoTrainerll of the therapeutic endoscopic interventions that are famil-

ar in conventional endoscopy can also be performed in the

eep small bowel using DBE. However, there are a few factorshat make these interventions more difficult. First, there is aong scope with a thin working channel and consequentlyong, thin probes, making very careful handling necessary.espite the balloons, which help stabilize the position of the

cope, it is sometimes tricky to obtain a good, stable positionor difficult procedures, eg, for resecting large polyps. Inddition, the lumen is narrower in the small bowel than in thetomach or colon, for example, and the small-bowel wall isery thin, comparable to the right-sided colon. The latteroint in particular can be demonstrated very impressivelysing argon plasma coagulation with different energy levelsr marking a position with india ink, for example.

ummaryBE is a complex examination and should therefore only beerformed by experienced endoscopists. The best method ofeaching DBE is step-by-step training. Lectures and videosre very useful during the initial steps, whereas hands-onraining with animal models and demonstration of live DBErocedures are the main components used for providingraining in and teaching of DBE. Ex vivo pig models, such ashe modified Erlangen EndoTrainer, are preferable.

eferences. Yamamoto H, Sekine Y, Sato Y, et al: Total enteroscopy with a nonsurgical

steerable double-balloon method. Gastrointest Endosc 53:216-220, 2001. May A, Nachbar L, Wardak A, et al: Double-balloon enteroscopy: pre-

liminary experience in patients with obscure gastrointestinal bleeding or

igure 6 The flexed tip of the enteroscope and a small loop of thenteroscope.

chronic abdominal pain. Endoscopy 35:985-991, 2003

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. Heine GD, Hadithi M, Groenen MJ, et al: Double-balloon enteros-copy: indications, diagnostic yield, and complications in a series of275 patients with suspected small-bowel disease. Endoscopy 38:42-48, 2006

. Sun B, Shen R, Cheng S, et al: The role of double-balloon enteroscopy indiagnosis and management of incomplete small-bowel obstruction. En-doscopy 39:511-515, 2007

. Zhong J, Ma T, Zhang C, et al: A retrospective study of the application ondouble-balloon enteroscopy in 378 patients with suspected small-boweldiseases. Endoscopy 39:208-215, 2007

. Neumann M, Mayer G, Ell C, et al: The Erlangen Endo-Trainer: life-like

simulation for diagnostic and interventional endoscopic retrogradecholangiography. Endoscopy 32:906-910, 2000

. Neumann M, Hochberger J, Felzmann T, et al: Part 1: The ErlangerEndo-Trainer. Endoscopy 33:887-890, 2001

. Neumann M, Siebert T, Rausch J, et al: Scorecard endoscopy: a pilotstudy to assess basic skills in trainees for upper gastrointestinal endos-copy. Langenbecks Arch Surg 387:386-391, 2003

. May A, Nachbar L, Schneider M, et al: Push-and-pull enteroscopy usingthe double-balloon technique: method of assessing depth of insertionand training of the enteroscopy technique using the Erlangen Endo-

Trainer. Endoscopy 37:66-70, 2005