Endoscopic Mucosal Resection, Submucosal Dissection, and Full Thickness Resection Techniques

Endoscopic Mucosal Resection, Submucosal Dissection, and Full Thickness Resection Techniques

Juergen Hochberger1, Edris Wedi2, Peter Koehler3, SongSa Dammer4, and Thomas Brunk1

1 Vivantes Klinikum im Friedrichshain, Berlin, Germany

2 Sana Klinikum Offenbach, Offenbach, Germany

3 Federal Research Institute for Animal Health (FLI) Mariensee, Neustadt, Germany

4 St. Bernward-Hospital, Hildesheim, Germany


Endoscopic resection (ER) started with the introduction of snare polypectomy in the colon, esophagus, cardia, and stomach in Germany and in Japan at the end of the 1960s and beginning of 1970s [1].

Polypectomy as the name says is useful for the removal of polypoid lesions. The technique frequently fails when a soft standard snare is applied to remove an only slightly elevated lesion. With the introduction of saline‐assisted polypectomy in 1973 by Deyhle et al., the removal of flat lesions was facilitated [1]. This technique is nowadays the classic “endoscopic mucosal resection” (EMR) [25]. Mechanical alternatives include the use of a stiff monofilament snare to be pressed into the mucosa or the aspiration of mucosa into a plastic cap mounted onto the distal end of the endoscope [6, 7]. The cap is preloaded with a special fine asymmetrical snare placed into a narrow inner rim at the distal end of the cylinder and closed once the mucosal “mushroom” has been aspirated [7]. A common practice in the esophagus and cardia is today the aspiration of the mucosa into a transparent cylinder with externally deployable rubber bands, ligate a pseudo‐mushroom after mucosal aspiration, and to consecutively snare it off underneath the rubber band [8, 9].

Recently, “Underwater EMR” has gained increasing interest [10, 11]. The bowel is filled with water during EMR and conventional snare resection carried out. A recent metanalysis showed an improved “en bloc” resection rate as well as a lower recurrence rate [1214].

The search for techniques to resect even large mucosal areas with early gastric cancer and to get a thorough histopathologic diagnosis led to the development of “endoscopic submucosal dissection” (ESD) in Japan at the end of the 1990s [1520]. The concept is based on a freehand needle‐knife technique as applied in needle‐knife sphincterotomy for difficult access to the biliary or pancreatic duct in ERCP. A large submucosal fluid cushion serves as protective layer when the lesion is first isolated by means of a circular cut outside a safety zone marked beforehand by fine coagulation dots placed around the margins of the lesion. After this circumferential incision, the lesion is separated from the muscolaris propria at the level of the submucosa. This gives the technique the name of “submucosal dissection.” Various knives and special tools have been developed for this scope. The latest development in the field of endoscopic resection is “Endoscopic Full Thickness Resection” using an over‐the‐scope clip (OTSC)‐based system (eFTRD; Ovesco Corp; Tuebingen Germany) [1821]. An area up to 2 cm in the extra‐papillary duodenum and 3 cm in the lower gastrointestinal (GI) tract can be resected including the entire gastrointestinal wall. In the stomach, the situation is not clear yet as the gastric wall is thick. The system includes the principle of over‐the‐scope clip (OTSC) plus endoscopic cap resection of 90% of the tissue inside the macroclip using a flexible braided snare. After marking the area to be removed by fine coagulation dots including a safety zone of 2–3 mm around the lesion, the resection area is drawn into the transparent cylinder of the device by means of a grasping forceps and then kept in place by suction. A nitinol OTSC macroclip is then fired in order to form a tissue mushroom. Third, a snare fitted within the tip of the OTSC cylinder is closed via the external snare handle and current is applied to resect the tissue inside the OTSC about 2 mm over the base of the tissue mushroom. The technique is especially helpful for the treatment of circumscript recurrent adenoma on a scar in the colon.

In the following section, the key steps for proper acquisition of EMR, ESD, and endoscopic full thickness resection device (eFTRD) techniques as well as the prerequisites are explained. There is no doubt that a theoretical explanation of the techniques even when illustrated by images, schemes, and video sequences does not replace a one‐to‐one supervised preclinical and clinical teaching situation. However, we hope you will find some helpful tips for your daily practice.

Endoscopic mucosal resection

EMR techniques to be considered

Common EMR techniques according to organs


  • Saline‐assisted snare resection of flat lesions (classic “EMR”)
  • Resection of flat lesions using a stiff snare without prior injection


  • CapEMR
  • Band and snare technique


  • Cap resection for lesions up to 1 cm
  • Saline‐assisted snare resection of flat lesions (classic “EMR”)

Small intestine:

  • Saline‐assisted snare resection of flat lesions (classic “EMR”)

Special EMR techniques not considered

  • EMR via double‐channel endoscope “Pull and snare”
  • EMR via Machuuchi tube
  • Endoscopic resection techniques for submucosal tumors [23]
  • Other rarely applied techniques

Procedures to be considered

EMR is carried out in the entire gastrointestinal tract according to the same principle. Preferred localizations are colo‐rectum, stomach, esophagus, and small intestine. It can be part of any primarily diagnostic intervention in these organs, for example, within preventive colonoscopy. Accordingly, it can also be part of gastroscopy, enteroscopy, and endoscopic retrograde cholangiopancreatography (ERCP) procedures. As described above, EMR can be carried our as standard or as “Underwater EMR” after previous filling of the bowel segment with water, e.g., for the resection of colon polyps [1214].

Prerequisite level of expertise for endoscopic mucosal resection (EMR)

There is a large variety in the level of expertise needed for EMR depending on the lesion itself as well as the resection technique applied. As important as the mechanical act itself is today a daily training concerning the proper evaluation and classification of lesions according to endoscopic criteria for dysplasia and malignancy. Prerequisite training must also include submucosal injection using saline and marking of lesions that should be resected.

Supervised training in EMR mostly starts start in the second year of fellowship and should be taught together with injection and clip hemostasis after trainees have gathered sufficient experience in unsupervised gastroscopy and colonoscopy [22, 24] (Figure 19.1). An exact number is not known, but 50 unsupervised colonoscopies plus 100 unsupervised gastroscopies could be a good starting point for the first supervised steps in EMR. The learner should begin with uncomplicated colo‐rectal polyps of less than 2 cm and easy to reach, as for example, in the rectum.

More sophisticated techniques and EMRs of lesions found in more difficult locations such as the duodenum, the esophagus, or the stomach do require a far higher level of expertise and a prerequisite competence in complication management (defect closure and bleeding control) [22].

Schematic illustration of endoscopic learning pyramid for stepwise clinical skills acquisition in gastrointestinal endoscopy and the possible complementary use of training simulators.

Figure 19.1 Endoscopic “learning pyramid” for stepwise clinical skills acquisition in gastrointestinal endoscopy and the possible complementary use of training simulators.

(From Hochberger et al. [22] with permission of the authors).

Special considerations

The necessary skills for EMR are best obtained in an initial “hands‐on” training course and subsequent clinical guidance by an experienced endoscopist. It is a prerequisite that the trainee is familiar with indications for EMR. The trainee must know contraindications for endoscopic procedures in general and in particular for EMR. Specifically, the trainee has to be able to anticipate and to act upon procedure‐related complications during and after EMR.

Specific technical and cognitive skills for endoscopic resection techniques

EMR as well as all other endoscopic resection techniques discussed here require sufficient mastery of the following cognitive skills:

  • Indication and contraindications for the procedure
  • Proper localization of the lesion according to established land marks.
  • Ability to discriminate submucosal from mucosal lesions and to classify lesions macroscopically according to the Paris classification
  • The ability to properly describe colorectal, duodenal, and jejunal intestinal polyps over 2 cm in size additionally according to their growth pattern and rough surface structure according to the Japanese classification for Laterally Spreading Tumors (LSTs)
  • Ability to properly classify the surface microstructure of the lesion using a high‐resolution endoscope ± digital or conventional chromoendoscopy in order to properly judge endoscopic resectability and malignant potential (Kudo, NICE, JNET etc.)
  • Ability to select the proper endoscopic resection tools as well as instruments for the management of adverse events (AEs) like coag grasper, hemoclips, OTSC macroclips etc.
  • Ability to properly mark a lesion e.g. 5 cm cranially and caudally to the lesion with tattooing and metal clips in case of highly suspicious malignancy or resection by a colleague in a referral center
  • Ability to decide if the intervention is better postponed until the opportunity to have an appropriate discussion with the patient (and relatives) and if biopsies are helpful, or if it is rather appropriate and indicated to proceed directly to the intervention during the same procedure as a particular lesion is detected
  • Ability to adequately judge the need for an anesthesiologic, surgical, interventional, or endoscopic back‐up in case of complications or clinical deterioration of the patient and to correctly organize pre‐interventional logistics and inform colleagues potentially involved in elective difficult interventions
  • Ability to properly judge time frame, accessories, personal qualification and that of the assistant; the need for potential back‐up to carry out the procedure with a high probability of success and low risk of complications for the patient. In elective resections, these points have to be part of an adequate time management and planning of resources in the forefront, no later than the day before the intervention
  • Correct interpretation of clinical signs and symptoms during as well as following the procedure, such as abdominal pain due to bloating versus an “acute abdomen” due to perforation after colonoscopic or duodenal interventions
  • Available diagnostic measures and imaging techniques for the detection of procedure‐related complications (e.g., computed tomography (CT) scan; US; plain abdominal X‐ray film)
  • Evaluation of the histologic result. This is true for an uneventful course but also in the case of complications that may lead to the necessity of endoscopic or surgical management
  • Scheduling of endoscopic follow‐up surveillance intervals according to the histologic result
  • Management of late complications such as strictures or local tumor recurrences, non‐surgical, or surgical

Equipment for EMR

The proper endoscope

Length, stiffness, and width of the instrumentation channel of the endoscope used play an important role for the success, ease, and potential complication management of the procedure.

For delineation of the lesion and possible marking of the resection area with coagulation dots, the endoscope with the best optical quality and features such as digital chromoendoscopy and if available Zoom function should be used. In the upper GI tract, this is often a slim, high‐resolution standard gastroscope (e.g., Olympus 190 series; Olympus Japan; Fuji 760 Z or R; Fujifilm Japan) whereas in the colon standard colonoscopes often provide the best optical quality available. For the resection/therapeutic intervention itself, the change to a therapeutic high‐resolution gastroscope with a channel of 3.8 mm is advisable. It allows rapid clearance of the resection bed in case of bleeding by rinsing and effective suction and may be crucial for the successful outcome of the intervention. For the duodenum, including the papilla a duodenoscope is often helpful or the appropriate instrument. At the level of the lower duodenal knee and in the third part of the duodenum, a standard or pediatric colonoscope may be advisable. In the rectum, a therapeutic gastroscope may prove favorable as it is easier to maneuver than a long routine colonoscope. Especially for resections over the hemorrhoidal plexus in the distal rectum, the short instrument proves helpful. EMR in the jejunum is possible by means of a pediatric colonoscope up to 30–50 cm distal to the ligament of Treitz. In principle, EMR can be carried out in the entire small intestine, for example, in familiar adenomatous polyposis (FAP) patients by means of a therapeutic double‐balloon or motor‐driven spiral enteroscope (e.g., EN580T Fujifilm, Japan; Olympus PowerSpiral PSF‐1, Olympus Tokyo, Japan). EMRs of tumors of the papilla of Vater (Figure 19.2) require advanced skills in ERCP and have to be discussed separately. Special locations of EMRs have been described, such as the pharynx and hypopharynx or in the common bile duct on the percutaneous–transhepatic route [25, 26].

Equipment independent of the procedure

Adequate monitoring and supervision during sedation

Sedation should be carried out according to national guidelines. In cases of severe comorbidity or extremely complex interventions, general anesthesia should be considered. EMR procedures in large lesions or with technically difficult anatomical access may take considerable time, for example, up to 2–3 hours.

Photo depicts essential accessories for interventional endoscopy: CO2 insufflation (left) and water flush pump (right).

Figure 19.2 Essential accessories for interventional endoscopy: CO2 insufflation (left) and water flush pump (right).

CO2 insufflation

CO2 insufflation is today the standard for diagnostic and especially therapeutic endoscopy in the entire GI tract. CO2 is absorbed 300 times faster than room air by the intestine and exhausted in exhaled air. In reduces the risk of an “abdominal compartment syndrome” with the risk of vomiting and aspiration in long therapeutic colonic interventions, the risk of over‐extension of the small intestine in upper GI interventions or colonic interventions in the right‐sided colon and finally favors rapid re‐absorption by the peritoneum in case of macro‐ or micro‐perforation. Most manufacturers provide specific insufflation devices for their endoscopes (Figure 19.2).

Endoscopic flush pump

A separate flush pump (e.g., “Endowasher” Griessat Endotechnik, Solingen, Germany) operated by a foot switch and coupled in by means of a separate “jet channel” Y‐adapter at the level of the biopsy valve facilitates the removal of debris, blood, or mucus. This way, the water pump can be operated without taking the instrument out of the accessory channel during irrigation and seems essential for ER techniques (Figure 19.2).

Organ‐specific equipment

The equipment for EMR depends on the individual lesion and anatomical situation and the resection technique planned. Criteria to select specific equipment include size, macroscopic appearance, and location of the target lesion, and may vary considerably.


  • Standard or pediatric colonoscope
  • Saline‐assisted EMR

    • Injection needle 21G (0.7 mm) with saline ± epinephrine, for example, 1:250,000 and indigocarmine blue 0.002%
    • Different stiff snares of a size of 15–35 mm (standard snares have often a size of 20–25 mm)
    • Hemoclips for colonoscopic use
    • Polyp trap to be interposed into the endoscope suction at the level of the attachment to the endoscope light source
    • Polyp retrieval net (e.g., Roth net, US Endoscopy, Mentor, OH, USA)


  • High‐resolution standard diameter adult gastroscope
  • For CapEMR

    • Injection needle 21G (0.7 mm) with saline ± epinephrine, for example, 1:250,000 and indigocarmine blue 0.002%
    • Oblique or straight transparent cap with inner rim (Olympus Optical, Tokyo, Japan) adopted to the outer diameter of the endoscope (e.g., Cap No. 3 for many standard gastroscopes)
    • 25 mm multifilament asymmetrical snare (which fits all types of caps; Olympus Optical, Tokyo, Japan)

  • Hemoclips for use in the upper (or lower) GI tract
  • For band and snare EMR technique

    • Ready available kit with multiligation cylinder equipped with six rubber bands and special hexagonal snare (Cook Medical, Winston‐Salem, USA; Figure 19.6; Boston Scientific Natick, MA)
    • Alternatively, a variceal band ligation set plus standard snare in case of a single lesion
    • Polyp retrieval net (e.g., Roth net, US Endoscopy, Mentor, OH, USA) for retrieval from the gastric fundus
    • Polyp trap in case of the use of a large channel gastroscope to be considered (interposed between suction tube and endoscope)


  • High‐resolution gastroscope
  • Saline‐assisted EMR

    • Injection needle 21G (0.7 mm) with saline ± epinephrine, for example, 1:250,000 and indigocarmine blue 0.002%
    • Different stiff snares of size 15–35 mm.
    • Hemoclips for use in the upper (or lower) GI tract Polyp trap to be interposed into the endoscope suction at the level of the attachment to the endoscope light source
    • Polyp retrieval net (e.g., Roth Net, US Endoscopy, Mentor, OH, USA)
    • Polyp trap in case of the use of a large channel gastroscope to be considered (interposed between suction tube and endoscope)


  • High‐resolution gastroscope and therapeutic side‐viewing duodenoscope. In the third part of the duodenum, a pediatric colonoscope is often helpful
  • Saline‐assisted EMR

    • Injection needle 21–23G (0.7–0.5 mm) with saline ± epinephrine, e.g., 1:250,000 and indigocarmine blue 0.002%
    • Different snares of a size of 15–20 mm
    • Hemoclips for use in the upper or lower GI tract.

      [Note: When a side‐viewing duodenoscope is usedrotable (blue), MicroTech endoscopy clips (MicroTech Endoscopy, An Arbor, Mi) are preferred

    • Polyp trap to be interposed into the endoscope suction at the level of the attachment to the endoscope light source
    • Polyp retrieval net (e.g., Roth net, US Endoscopy, Mentor, OH, USA) helpful in case particles are first deposited in the gastric fundus and then removed together

Major and minor papilla

  • EMR of ampullary lesions is addressed separately in Chapter 27 and will require additional ERCP related devices and accessories and on occasion EUS equipment (Figure 19.3).

Jejunum and deep small intestine

  • Therapeutic enteroscope, for example, therapeutic double‐balloon enteroscope (e.g., Fujinon EN450T5)
  • Pediatric colonoscope 175 cm for the first 30–50 cm of the jejunum often feasible. For interventions using a pediatric colonoscope or enteroscope of max. 200 cm, standard colonoscopy equipment often works
  • Saline‐assisted EMR in double‐balloon enteroscopy/enteroscope (DBE)

    • Injection needle 23G (0.5 mm) 270 cm long with saline ± epinephrine, for example, 1:250,000 and indigocarmine blue 0.002%
    • Special DBE snares of size 15–25 mm
    • Hemoclips DBE (Olympus Optical, Tokyo, Japan) or for use in the lower GI tract (e.g., Boston Scientific, Natick, MA)
    • Polyp trap to be interposed into the endoscope suction at the level of the attachment to the endoscope light source
    • Polyp retrieval net (e.g., Roth net, US Endoscopy, Mentor, OH) in case of retrieval after interdisposition in the fundus of the stomach.

Salvage accessories

  • “Over‐the‐scope clip,” “bear trap” (OTSC; e.g., Ovesco Tuebingen, Germany): The over‐the‐scope macroclip exists in various sizes and configurations. The configuration is similar to the working principle of a bear trap. A Nitinol macroclip is mounted on a transparent housing attached to the distal end of the endoscope. The clip is released similar to the elastic rubber bands in variceal band ligation by means of a traction “wire” made of heavy‐duty suture line. Before application, the target area is pulled or sucked into the cylinder [27].
  • In ulcer hemostasis, usually the traumatic type (t‐type) is preferred in order to guarantee a secure capture of the sometimes scarred wound ground. However, for perforation closure in the small or large intestine with a thin wall, the atraumatic type (a‐type) with rounded teeth is usually preferred. In the upper GI tract and the colon, an OTSC of wall in order to avoid secondary perforation 17.5 mm (type 11) is used. Exclusively for use in the upper GI tract, a thinner 16.5 mm (type 10) exists and exclusively for the rectum a larger 21 mm (type 12) model is available, each as traumatic or atraumatic type.

Patient preparation

Focus on informed consent

To justify EMR within a procedure, it has to be covered within the informed consent of the patient prior to the intervention. If EMR appears to be indicated during a primarily diagnostic intervention, the physician has to decide if he needs additional information for example, a rectal ultrasound or magnetic resonance imaging (MRI) of the lesser pelvis to exclude invasive growth or if it seems justified to proceed to resection within the same session. Furthermore, it has to be cleared if alternative treatment options have been discussed sufficiently and if the patient would be ready to accept that she/he needs hospitalization after a complex procedure. Especially in the upper GI tract without the necessity of a special preparation and easy and fast access, it is rather recommended to come back in a second session than to proceed to an invasive procedure without having discussed the next steps sufficiently with the patient.

Patient condition and alternative treatment options

EMR in difficult locations or large lesions may require a long‐lasting procedure. Fitness of the patient for prolonged sedation during this intervention and complication management has to be checked early. For special interventions, anesthesia may be required for airway management. Furthermore, the intervention has to be seen in an interdisciplinary context and alternatives be balanced. Is this the best treatment option for the patient also in the eyes of his relatives or of a general surgeon? Often, it is better to postpone an elective intervention if conditions are not optimal or patient and relatives not thoroughly convinced of the procedure.

Patient preparation

The general preparation is according to the “carrier procedure,” for example, gastroscopy or colonoscopy. Special medication such as anticoagulants should be discontinued according to national guidelines and individual recommendations, for example, of the attending cardiologist [28].

c19i001 Key steps for proper technique in EMR (see Video 19.1)

Evaluation of the lesion

EMR is focused on the removal of epithelial lesions. The first step to an exact evaluation of the lesion is optimal visualization. One should always inspect the entire lesion, including the proximal and lateral margins. Debris or stools should completely be flushed off the lesion and its proximity. Within the last decade, new technical features such as digital chromoendoscopy (NBI, BLI, LCI, I‐scan), zoom and high‐resolution endoscopy (HRE) have added a significant diagnostic yield to standard video endoscopes [29]. Optical contrast such as NBI or BLI can help to better delineate the margins of the lesion and to evaluate the surface structure and the so‐called “pit pattern” [30]. Already by optical appearance, an experienced endoscopist may correctly classify a lesion as suspicious or endoscopically treatable about 80% of the time [31]. However, especially in the upper GI tract and in the rectum, noninvasive imaging such as EUS, CT, or MRI may add significant information on local lymph node status and invasion depth. The value of submucosal (sm) injection as diagnostic tool will be discussed in the next section. In uncertain cases, clip marking 1–2 cm from the lesion, exact determination of the location, biopsies, and a second examination with more information may be a good alternative [32].

Image described by caption.

Figure 19.3 (a, b) Endoscopic snare resection of a large 2.5 cm × 3 cm ampullary tumor using a side‐viewing endoscope: 5 Fr polyurethane drainage still in place. Endoscopic ultrasound (EUS) and ERCP with pancreatic and biliary sphincterotomy and bi‐ductal stenting had been performed 2 weeks earlier to guarantee a safe ductal access even in case of complications. (c–e) Generous submucosal injection using a Carr‐Locke spiral 25G injection needle (US Endoscopy, USA) and a saline/epinephrine solution (1:250,000) with 0.002% indigocarmine blue addition. (f) A complete lifting of the lesion is achieved as important diagnostic criterion for endoscopic respectability. (g–j) Piecemeal EMR is carried out using a 25 mm multifilament snare (Griessat Endotechnik Corp., Solingen, Germany). (k) Macroscopically adenoma‐free resection base as final result. (l, m) As last step, a new pancreatic and biliary drainage is implanted to prevent fluid retention.


In case of suspected or proven early malignant lesions, a prior marking including a safety zone of at least 3 mm from the lesion should be performed using thermocoagulation. The by far easiest tool to use is Argon plasma coagulation (APC) (e.g., 25 W, 0.3 L gas flow “forced coag” in the VIO generator; ERBE Medizintechnik, Tuebingen, Germany). Alternatives are, for example, the tip of a snare at the lowest Wattage possible in order to avoid a thermal injury and secondary perforation of the entire wall.

Submucosal injection

Submucosal injection can help in two senses as diagnostic tool. Adding indigocarmine blue to the injection solution (e.g., Indigo CarminTM, American Regent, Shirley, NY, 1.5–2 mL of a commercial 0.8% solution to a bag of 500 cc of saline) turns the underground to a mid blue after submucosal injection while the lesion remains bright. This leads to a sharp delineation of even shallow lateral margins.

Furthermore, the ease to separate layers at the level of the submucosa and the degree of adhesion serve as important diagnostic tools. In case of a clear “lifting” of the entire lesion, resection is almost always possible. A so‐called “non‐lifting sign” of the lesion with central adherence and lateral bulging, in the extreme case similar to a floating tire, always signalizes an increased perforation risk or the risk of incomplete resection. An insufficient or only moderate lifting is not always equivalent to malignant infiltration but may occur due to local scarring and prior inflammation, for example, in flat adenomata in the colon or in case of prior incomplete attempts at resection. However, a “non‐lifting” even after generous fluid injection makes the lesion suspicious and should raise the question whether it is better to continue resection or better to take biopsies and send the patient either to an expert center, or in case of proven malignancy send the patient directly to the surgeon.

We favor submucosal injection due to the reasons mentioned. However, for single instruments/techniques, namely the “ligate and snare” technique using rubber bands for tissue ligation prior to resection, it seems that a larger tissue volume of mucosa can be accomplished without prior submucosal injection. Furthermore, some authors prefer to not use submucosal injection in combination with a stiff monofilament snare [33]. The addition of epinephrine to the injection substance is contradictory in the literature [34].

An important practical point in submucosal injection is that in contrast to ulcer hemostasis where the needle is rather pressed into the tissue to avoid leakage of fluid, in case of EMR‐/ESD‐injection, the target layer is the very superficial submucosa. Wall perforation of the needle leading to transmural leakage during further injection and the following resection procedure should be avoided. The needle is first advanced from the catheter and held about 1–2 mm over the mucosal surface. The assistant is asked to start injection. Only when fluid leaves the needle, it is advanced with a sharp “go” to just perforate the mucosa and then immediately pulled back 2–3 mm. This will lead to a typical submucosal blowing up of the mucosa. Trainees must be made aware that if the needle is deeply stuck into the tissue and nothing happens, the fluid is being injected beyond the organ wall. We use a standard 23G shielded universal injection needle (Interject; Boston Scientific, Natick, MA USA) for all EMR and ESD procedures.

New injection substances for EMR and ESD show the advantage of a higher viscosity with longer lasting fluid cushion and have been cleared by FDA (e.g., Eleview; Aries Pharmaceuticals, San Diego, CA, USA; ORISE™; Boston Scientific, Natick, MA).

Resection techniques for EMR

In this chapter, we limit our discussion to the description in detail of the three most common EMR techniques applied.

Classic EMR (lift and cut technique; saline‐assisted snare resection)

Aim of the technique is to enable the resection of flat lesions in which a conventional snare would slip over the pathology (Figure 19.4). The technique is the most popular EMR technique applied especially for the removal of non‐pedunculated colorectal polyps. Technically, submucosal injection of saline or a glycerol solution (e.g., Glycerol 10%, Fresenius Kabi, Germany) provides a soft fluid cushion into which the snare can easily be pressed. A bulging of the mucosa to the interior of the snare provides a higher friction and better grip of the snare filaments when the snare is closed. This increases the tissue volume per cut. Resection proceeds often easier and faster after the first specimen has been removed. A clear step between the muscular resection base and the mucosal surface facilitates subsequent cuts. Following the first resection, the snare is placed, for example, with the left side into the mucosal defect and the right side is placed onto the lesion elevated by submucosal injection. Pressing the snare onto the ground and closing it slowly, the next piece of mucosa to the right is resected. This is repeated until the entire lesion as well as a lateral safety margin has been removed. The technique is therefore often called “piecemeal resection” in case of a larger resection area and multiple particles.

It is advisable to start at the lateral margins of the lesion, incorporating a “safety margin” of 2–3 mm in order to reduce the risk for local recurrences (Figure 19.4). The tissue fragments removed are mostly sucked off via the instrumentation channel and collected in a “polyp trap.” Alternatively, larger fragments can be removed my means of a retrieval net (e.g., “Roth net,” US Endoscopy, Mentor, OH). Care should be taken that the particles are placed in a sufficient quantity of formalin and sufficiently large specimen container.


CapEMR uses the principle to suck the lesion into a straight or oblique transparent “distal attachment cap” (Figure 19.5). Caps are provided in different diameters and have an inner rim at their distal end.

Photo depicts (a–e) Indigocarmine blue colorant for improved delineation of flat lesions and later resection margins.

Figure 19.4 (a–e) Indigocarmine blue colorant for improved delineation of flat lesions and later resection margins. “Indigo” is added in a small quantity to the saline/±epinephrine submucosal injection fluid (0.5 mL of indigo into 500 cc of saline): flat laterally spreading colonic adenoma clearly visible for piecemeal resection of a lateral safety zone together with the lesion. (f, g) Complete clip adaptation of the margins in a patient at increased bleeding risk.

The cap resection technique implies the use of a special 25 mm asymmetrical multifilament snare in the form of the head of a dolphin to be placed into the distal inner rim of the cylinder. As this maneuver needs training and the application is more complicated nowadays, the equally effective “band and snare” technique is often the preferred method.

At first, the endoscope is gently introduced into the upper esophagus. Pressing the rinsing and the suction button of the endoscope at the same time removes mucus from the inner side of the cylinder and leads to a clear vision. At first, a marking of the area to be resected is performed, e.g., using an APC probe (18 W, “forced,” 0.5 seconds pulses forced coag, ERBE VIO prograde probe), including a sufficient safety zone of adjacent inconspicuous tissue (minimum 2–3, recommended 5 mm).

In the case of a circumscript Barrett’s cancer, the surrounding Barrett’s epithelium may be resected at the same time or just the prominent part with secondary thermal ablation [35, 36], an initial marking of the resection field is performed, extending at least 3 mm around the lesion. In case of an area exceeding 15 mm, “en bloc” resection using the ESD technique is preferred over EMR (see “Endoscopic submucosal dissection” section).

As a second step, the mucosa is generally lifted by submucosal injection using pure saline or recently favoured, a viscous solution such as a 6% glycerol solution (e.g., Glycerosteril; Fresenius‐Kabi, Germany) with an adjunct of indigocarmine blue (0.5 mL of 2% indigocarmine added to 500 cc of the basic solution). One should not be afraid of “overinjection” as passing by with the endoscope from cranially to caudally after a short time the fluid will rapidly disappear.

Image described by caption.

Figure 19.5 (a–f) Cap resection (EMRc) for a flat “high‐grade intraepithelial neoplasia (synonymous to “high‐grade dysplasia”) (HG‐IEN) at the upper end of a long segment Barrett’s esophagus: (a) “distal attachment” caps (Olympus Optical, Tokyo, Japan) of various sizes with straight or oblique distal ends according to H. Innoe, Japan. (b) Target area is identified and marked. (c) After marking the 25 mm asymmetrical snare is placed into the inner rim of the cylinder. (d) The lesion aspirated into the transparent cylinder and the snare closed. The lesion with the surrounding safety area appears like a mushroom captured in the snare after releasing the suction. (e) Resection bed after electrosurgical resection. (f) Resection specimen stretched out and pinned on cork before histopathological evaluation (see also Video 1.5).

For deposition of the snare within the cylinder, the transparent hood is gently pushed against normal mucosa, for example, in the proximal esophagus, in order to not disturb the lesion itself until the snare is properly seated along the rim of the cylinder. The snare catheter with the snare closed is then advanced until it can be seen within the cylinder. The assistant has then to slowly open the snare the way it is deployed in a clockwise fashion onto the inner rim of the distal cylinder. This just as much that the snare surrounds completely the cylinder but does not protrude over the rim into the lumen. The snare catheter is then fixed with the little finger of the left hand at the endoscope in order to avoid dislocation from the inner rim while the endoscopist is moving. The cylinder tip is then moved to the targeted tissue, suction is applied until a full “red‐out” of the cylinder with tissue. The snare is quickly and completely closed before the suction is released and the snare is slightly advanced as cutting current is applied to resect the lesion. Not to start resection before release of the captured “mushroom” in order to allow the muscularis propria layer to stretch out completely is mandatory in order to avoid local perforation. The popularity of this technique has decreased within the last years due to the simplicity of the “band and snare” technique with premounted kits (see “Band and snare” section) and the increased spread of “ESD” (see “Endoscopic submucosal dissection” section) for larger lesions.

Time should not be wasted to take off the specimen at this point but rather to go back to the esophagus again and see if there is any bleeding or wall defect. Both should be fixed immediately in the case that either of this has occurred.

Multiple resections can be accomplished this way in the same session.

After resection, care should be given to hemostasis of small vessels using coagulation forceps or hemoclips.

“Band and snare” EMR

A technically simple method to resect focal Barrett’s mucosa with a visible lesion up to 10 mm is the so‐called “ligate and cut” technique [16, 34], e.g., using the “Duette” system (Cook Medical Bloomington, Indiana) [17, 37]. A transparent cylinder with six rubber bands similar to the “sixshooter” variceal band ligation device is mounted on the distal end of the endoscope. In contrast to the variceal band ligator set, the EMR set has a different handle and contains a hexagonal snare that can be introduced into the instrumentation channel via an additional access port in the handle (Figure 19.6).

Photo depicts Band and snare mucosal resection kit (Duette, Cook Medical, Winston-Salem, USA). A hexagonal monofilic snare (a) is used in combination with a special multiligation system (b) for repeated mucosal aspiration, rubber band ligation, and snare resection under the rubber band.

Figure 19.6 “Band and snare” mucosal resection kit (“Duette,” Cook Medical, Winston‐Salem, USA). A hexagonal monofilic snare (a) is used in combination with a special multiligation system (b) for repeated mucosal aspiration, rubber band ligation, and snare resection under the rubber band.

The technique is applied without prior injection. The mucosa is sucked into the cylinder and the band is fired. The snare is introduced and resection of the created ligation mushroom underneath the band is carried out. Immediately after the next band is placed adjacent to the previous resection site in order to avoid tissue bridges. Wall perforations using the ligate and cut technique are rare [17, 38].

Endoscopic submucosal dissection

ESD is composed of a sequence of different steps:

  1. Identification and marking of the lesion with a sufficient lateral safety margin
  2. Submucosal injection and tissue elevation
  3. Circumferential or partial incision around the lesion
  4. Submucosal dissection with “en bloc” removal of the lesion and retrieval
  5. Careful hemostasis with occlusion of vessels at the resection base using a coag grasper or short‐arm hemoclips
  6. Preparation of the specimen for histopathologic evaluation.

In the following section, we will go through the different steps of ESD

Lesions to be considered for ESD

Procedures to be considered for ESD in the upper and lower GI tract are mucosal cancers, lesions containing high‐grade intraepithelial neoplasia or lesions suspect for early cancer exceeding the size of (10–) 15 mm which cannot be safely resected “en bloc” for complete histopathologic work‐up using snare resection techniques [39].

Skills for ESD and who should do it

Prerequisite level of expertise and skill for learning ESD

ESD is currently a technique for the “high‐end” endoscopist requiring a long practice in interventional endoscopy and complication management. ESD originated in Japan and is a relatively new procedure in the Western world. The prerequisites and the learning curve to perform a “safe” and sufficiently fast ESD still have to be defined [35, 39]. ESD is a “freehand” needle‐knife technique similar to needle‐knife sphincterotomy when gaining access to the common bile duct in difficult ERCP situations. In the beginning, ESD is time‐consuming and carries an increased complication risk, especially for perforation [34,3638, 40].

Special considerations for ESD

Initial steps in learning ESD should be accompanied by a training program and expert teaching. Early training steps include a progressive approach to the technique in “ex vivo” pig stomachs. Training in live pigs is a useful next step to acquire ESD hemostasis skills and to train the technique in an environment with natural GI motility, elasticity and bleeding. For clinical practice, a close student–teacher relationship and sufficient phases of watching the procedure seem important before a student goes to unsupervised clinical ESD. At least 20 ESD procedures in animal/ex vivo models are required before the trainee reaches a sufficient speed and safety for limited “en bloc” resections (<30 mm) preferentially in the gastric antrum or rectum. ESGE recommends that at least the first 10 procedures in humans should be done under the supervision of an ESD‐proficient endoscopist [35]. Systematic training programs will help to avoid pitfalls in this undoubtedly fascinating technique.

Specific technical and cognitive skills for ESD

To start ESD, an extensive experience in complication management in the upper and lower GI tract and several years of experience in interventional endoscopy are required including EMR for benign and early malignant lesions. Table 19.1 shows the recommendations of the European Society of Gastrointestinal Endoscopy (ESGE) for Training in ESD [35].

Equipment for ESD

General considerations on ESD equipment

The equipment for ESD depends much on the individual preferences and resection technique used [22, 34, 40]. For lesions located in the lower and upper GI‐tract standard gastroscopes and colonoscopes may be used. However, our personal preference is a slim therapeutic high resolution (HR) gastroscope (Fujinon EG 760 CT; Fujifilm Medical, Tokyo, Japan;) with the advantage of a large suction channel. Especially, in a strongly vascularized environment as in the distal rectum, a large channel for suction is of major advantage.

Table 19.1 List of recommendations for training in Endoscopic Submucosal Dissection (ESD) of the European Society of Gastrointestinal Endoscopy (ESGE). From Pimentel Nunez et al. [35].

  1. Skills/competence to start ESD

    • Advanced endoscopy diagnostic practice is advised before initiating ESD training
    • Training in ESD should be considered only by fully trained endoscopists.
    • Proficiency in EMR and adverse event management is recommended before starting ESD training
    • Knowledge of the “ESD theory” is necessary before and during training

  2. Training

    • Live conferences and meetings are suggested before and during ESD training
    • ESGE discourages the starting of initial ESD training in humans
    • Practice on animal and/or ex vivo models is useful to gain the basic ESD skills. ESGE recommends performing at least 20 ESD procedures in these models before human practice, with the goal of at least eight en bloc complete resections in the last 10 training cases, with no perforation
    • ESGE recommends supervision during training as it seems effective in improving the skills of trainees
    • In order to understand strategies and risk management, ESGE recommends observation of experts performing ESD in tertiary referral centers. At least 20 ESD procedures observed and five procedures as assistant, ideally within a short period of time, are recommended
    • Performance of ESD in humans should start on carefully selected lesions, ideally small (<30 mm), located in the antrum or in the rectum for the first 20 procedures (initial period). Beginning human practice in the colon is not recommended
    • ESGE recommends that at least the first 10 procedures in humans should be done under the supervision of an ESD‐proficient endoscopist

  3. Knowledge and maintaining competence

    • Endoscopists involved in ESD should have specific knowledge of the instrumentation, technique, and electrosurgical equipment
    • Endoscopists performing ESD should be able to correctly estimate the probability of performing a curative resection based on the characteristics of the lesion and should know the benefit/risk relationship of ESD when compared with other therapeutic alternatives
    • Endoscopists performing ESD should know how to interpret the histopathology findings of the ESD specimen, namely the criteria for low risk resection (“curative”), local risk resection, and high risk resection (“non‐curative”), as well as their implications
    • Ideally, endoscopists properly trained in ESD should start performing ESD at their own center only after an ESD expert has confirmed that they have the knowledge and skills to start performing ESD
    • ESD should be performed only in a setting where early and delayed complications can be managed adequately, namely with the possibility of admitting patients to a ward, and access to appropriate emergency surgical teams for the organ being treated with ESD. In addition, centers performing ESD should have access to expert gastrointestinal pathology
    • In order to maintain proficiency in ESD, ESGE recommends a minimum case load of 25 ESD procedures per year
    • All procedures should be registered in a prospective database covering items such as endoscopic classification, location and size of the lesion, technique used, en bloc resection rate, complication rates, time of procedure, R0 resection rate, and final histopathology (including type of resection). En bloc resection rates should be above 90%, and the perforation rate should be below 3%, with a lower than 1% need for surgery because of complications

Essential equipment for ESD

Upper GI tract, recto‐sigmoid, left‐sided colon

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Jul 31, 2022 | Posted by in GASTOINESTINAL SURGERY | Comments Off on Endoscopic Mucosal Resection, Submucosal Dissection, and Full Thickness Resection Techniques
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