Endoscopic Submucosal Dissection Experts Research Articles

Impact of Traction Direction in Traction-Assisted Gastric Endoscopic Submucosal Dissection (with Videos)

BackgroundThe impact of traction direction in traction-assisted gastric endoscopic submucosal dissection (ESD) has not been adequately investigated. A clip with line (CWL) is a classical single-directional traction device. In contrast, a spring and loop with clip (SLC; S–O clip) is a newly developed multidirectional traction device.AimsTo investigate the impact of traction direction in gastric ESD by comparing the procedure-related outcomes of CWL-assisted ESD (CWL-ESD) and SLC-assisted ESD (SLC-ESD).MethodsWe retrospectively examined 140 patients with superficial gastric neoplasms who underwent SLC-ESD or CWL-ESD by a single ESD expert during November 2017–September 2020. The traction direction was classified based on the endoscopic finding in the following five categories: proximal, diagonally proximal, vertical, diagonally distal, and distal. In SLC-ESD, we set vertical traction, using the multidirectional traction function. Propensity score matching was conducted to compensate for the differences in lesion size, injection function of electrosurgical knife, ulcerative lesion, lesion location, and lesion position. The primary outcome was gastric ESD procedure time.ResultsPropensity score matching created 42 pairs. The median gastric ESD procedure time in the SLC-ESD group was significantly shorter than that in the CWL-ESD group (28.3 min vs. 51.0 min, P = 0.022). All traction direction in the SLC-ESD group was vertical, while only 16.7% in the CWL-ESD group. En bloc resection was attained without perforation in all the patients in both groups.ConclusionOur findings suggest that SLC can provide vertical traction, which reduces the gastric ESD procedure time.Graphical Multidirectional traction devices can provide vertical traction in most cases of gastric ESD, unlike single-directional traction devices. Vertical traction may reduce the gastric ESD procedure time.

Learning curve for peroral endoscopic myotomy in therapeutic endoscopy experts and nonexperts: Large single-center experience.

Reports on learning curve for peroral endoscopic myotomy (POEM) in therapeutic endoscopy nonexperts are limited. We aimed to assess the number of cases required to achieve POEM proficiency for endoscopic submucosal dissection (ESD) experts and nonexperts. This is a retrospective study at the largest POEM referral center in Japan. POEM between April 2014 and December 2020 were included. Nonexperts and ESD experts were divided by training phases: A, 1-20; B, 21-40; C, 41-60; D, 61-80; and E, 81-100 cases. Primary outcome was operation time, and the phase to reach target time (83 min) was investigated. Secondary outcomes were clinical success rate, adverse events, and post-POEM gastroesophageal reflux disease (GERD). Five hundred and sixty-six cases were performed by 14 nonexperts, and 555 cases by 15 ESD experts. As the primary outcome, operation time in nonexperts was: A, 95 (79-115.8); B, 86.5 (71-105); C, 80 (70-100); D, 73 (64.5-100.5); and E, 73.5 (57.8-88.8) min, while in ESD experts: A, 90 (74-128); B, 77 (70-92); and C, 77 (70-93.5) min (median [interquartile range]). Operation time decreased significantly as experience increased in both groups (P < 0.001), and nonexperts required 41-60 cases to achieve proficiency, while experts required 21-40 cases. As secondary outcomes, in nonexperts, clinical success was 96.9-100%, adverse events were 5.0-9.2%, symptomatic GERD was 11.8-26.5%, and proton pump inhibitor (PPI) intake was 11.5-18.7% in each phase. While in experts, clinical success was 96.2-100%, adverse events were 3.0-5.8%, symptomatic GERD was 14.6-22.0%, and PPI intake was 12.6-17.9%. There were no significant differences among training phases. Non-ESD experts require more cases to achieve proficiency in POEM. These results are useful for establishing POEM training programs and institutional implementation of the procedure.

Novel image enhancement technology that helps find bleeding points during endoscopic submucosal dissection of gastric neoplasms.

The management of bleeding during endoscopic submucosal dissection (ESD) is critical and related to the procedure time. We collaborated on a new image enhancement algorithm with parameter optimization for clinical use being developed by FUJIFILM Co. and processed white light image data offline to evaluate the effectiveness of this technology. This study aims to evaluate the clinical usefulness of this technology. Eighteen video scenes of bleeding points from five gastric ESDs were selected and processed by the new image enhancement algorithm. The time until a bleeding point was found, visibility of a bleeding point, and color abnormality of the submucosal layer were evaluated by ESD experts, ESD trainees, and endoscopy trainees. The color differences between the bleeding point and the surroundings in CIE-L*a*b* color space were calculated in the original and enhanced images. The time until a bleeding point was found in the enhanced videos was significantly shorter than that in the original videos (11.10s vs 13.85s) (P=0.017). On a 5-point (-2 to +2) Likert scale of visibility, the enhanced image was slightly superior to the original (+0.45), and the appearance of the submucosa was comparable between images (+0.14). The color difference among the bleeding areas on the enhanced images was significantly larger than that on the original images (10.93 vs 8.36). This novel image enhancement algorithm emphasizes the color difference between a bleeding point and the surrounding area, which would help find bleeding points faster during ESD for the less experienced endoscopists.

Asurvey of physician training and credentialing in endoscopic submucosal dissection in the United States.

Endoscopic submucosal dissection (ESD) is technically challenging, has a longer learning curve and a greater complication rate than most new endoscopic procedures. Formal training and credentialing guidelines for ESD are currently lacking in the United States (US). To survey ESD experts across the US to determine their learning process and obtain their opinion on how training and credentialing for ESD should develop. Anonymous electronic survey. ASGE members who are practicing US endoscopists. The survey was developed by iterative revisions of questions administered to three investigators who have been performing ESD for > 5years. The final survey was distributed electronically to US endoscopists who had previously attended ESD expert conferences. Thirty-five (58.3%) of 60 practicing ESD experts responded to the survey. A majority (91%) were in university-based, community, or tertiary care hospitals. All practitioners practiced on porcine explants and observed live ESD procedures as part of the training. Out of the participants, 75.8% received formal supervised hands-on training on porcine explants and/or humans before performing ESD independently. Fifty percent indicated that their facility had written guidelines specifically for ESD credentialing. Four out of 5 felt that credentialing requirements should include attending weekend ESD courses, observing live procedures, practicing on explants, and advanced endoscopic training in interventional endoscopy such as an additional year of fellowship. Survey completion rate of 58.3%. ESD training should include practicing on explants, observation of live procedures, training in interventional endoscopy, and attending educational courses. Credentialing guidelines for ESD based on expert opinion need to be developed in the US.

Development and clinical outcomes of an endoscopic submucosal dissection fellowship program: early united states experience

Adoption of endoscopic submucosal dissection (ESD) in the USA is challenging due to limited training opportunities. We describe the development of an ESD fellowship program in the USA and evaluate outcomes of ESD performed during this experience. A 1-year ESD fellowship was implemented under close supervision from a recognized ESD expert. The curriculum was tailored to the trainee based on their background and prior endoscopic training. Under the expert's discretion, the trainee started by assisting cases and was gradually allowed to begin performing portions of ESD, with increasing difficulty as determined by technical progress, until complete procedures could be performed. Technical characteristics, outcomes, and adverse events were recorded. A total of 72 consecutive ESD cases were performed during the training period, in which the trainee assisted/observed 19 cases, partially performed 18 cases, and mainly performed 26 cases. Mean lesion diameter was 44.5mm, with 79.2% colorectal cases. The trainee more frequently performed procedures with lower degree of fibrosis (p = 0.016). En bloc, complete, and curative resection was achieved in 84.7, 81.2, and 76.8% of cases, with no significant differences in resection outcomes or adverse events from trainee involvement. ESD can be safely and effectively taught within a 1-year advanced endoscopy fellowship. This was possible in the USA, even with limited gastric lesions, due to a progression focusing on easier portions of complex ESD procedures and advancing as technical progress allowed. Importantly, there was no increase in adverse event rate with trainee involvement in complex ESD cases.

Endoscopic Mucosal Resection with Circumferential Mucosal Incision for Colorectal Neoplasms: Comparison with Endoscopic Submucosal Dissection and between Two Endoscopists with Different Experiences.

Background/AimsEndoscopic mucosal resection with circumferential mucosal incision (CMI-EMR) may offer benefits comparable to those of endoscopic submucosal dissection (ESD), while requiring less technical proficiency than ESD.MethodsWe retrospectively compared the outcomes of CMI-EMR (n=34) and size-matched ESD (n=102), which were performed by a Korean endoscopist for colorectal epithelial lesions of 20–35 mm. Procedural parameters of CMI-EMRs performed by an American ESD novice (n=30) were compared with those performed by the Korean endoscopist.ResultsThe lesion size was 22.3±3.9 mm and 22.9±2.4 mm in the CMI-EMR and size-matched ESD groups, respectively (p=0.730). The resection time was 12.7±7.0 minutes in the CMI-EMR group and 45.6±30.1 minutes in the ESD group (p<0.001). The en bloc resection rate was 94.1% in the CMI-EMR group and 100% in the ESD group (p=0.061). There were no differences in the en bloc resection and complication rates of CMI-EMRs between a Korean and an American endoscopist.ConclusionsFor the treatment of moderate-size colorectal lesions, CMI-EMR showed a trend toward lower en bloc resection rate, but required shorter procedure time than ESD. CMI-EMR outcomes were similar when performed by a Korean ESD expert and an American ESD novice.

Video-based supervision for training of endoscopic submucosal dissection.

Adoption of endoscopic submucosal dissection (ESD) in Western countries has been limited by the difficulty in learning the procedure. Although a porcine model is commonly used for ESD training, without expert guidance the procedure is difficult to master. The availability of Western ESD experts is limited, and expert supervision through a remote video-based system may be a practical method for Western endoscopists to learn ESD. The aim of this study was to assess the value of video-based remote evaluation in supervising ESD training. Two Western endoscopists performed ESD training procedures in an ex vivo porcine model at least every 2 weeks until competency was achieved. Competency was defined as consistent en bloc resection of a 3-cm area within 30 minutes, and without perforation, using the proper ESD technique. A Japanese ESD expert at the National Cancer Center in Tokyo, Japan, analyzed the training videos, scored them, and provided written feedback for improvement after each training session and before the trainee's next training session. Endoscopist 1 reached competency at 23 procedures and endoscopist 2 reached competency at 25 procedures. No difference in skill improvement between the two endoscopists was noted. One trainee subsequently completed eight ESD procedures in patients, with curative en bloc resection and no complications. A standardized ESD training program including educational presentations/videos and preclinical animal training with expert guidance through a remote video-based system is an effective tool for learning ESD techniques in preparation for performing the procedure in humans.

Enhancing proficiency in performing endoscopic submucosal dissection (ESD) by using a prototype robotic endoscope.

Background and study aims: One of the challenges in performing endoscopic submucosal dissection (ESD) is the lack of counter traction during submucosal dissection. MASTER (Master and Slave Transluminal Endoscopic Robot) was designed to allow performance of complex endoluminal procedures using two arms with excellent control. This study aimed to compare the performance of ESD between endoscopists and novices using MASTER. Methods: This is a prospective study comparing the differences in performing ESD using MASTER in an ex vivo porcine stomach model among individuals with or without experience in surgery and endoscopy. Multiple standardized lesions of 20 mm2 were pre-marked on an ex vivo porcine stomach. Each participant received basic training in controlling MASTER before the ESD procedure. The operative time and size of specimen obtained by each participant were noted. Results: Nine individuals (three ESD expert endoscopists, three ESD non-expert endoscopists, and three non-clinician novices) participated in the experiment. All participants completed the ESD procedure for en bloc resection of standardized lesions using EndoMASTER without perforation. The mean times (mean ± SD) taken by ESD expert endoscopists, ESD non-expert endoscopists, and novices to complete Robotic ESD were 122 ± 58 s, 203 ± 150 s, and 561 ± 496 s, respectively. There was no statistically significant difference in the mean operative time to complete the ESD between the three groups (P = 0.242). When the performance of the six endoscopists was compared to that of the three novices, the endoscopists took an average of 162 ± 111 s to complete the ESD, while the non-clinicians required an average of 561 ± 496 s (P = 0.085). Conclusions: There was a trend to shorter operative time when comparing endoscopists to non-endoscopists in performing ESD using MASTER. The use of MASTER enabled the novice without endoscopy experience to complete the ESD procedure.

High-pressure injection of glycerol with HybridKnife for ESD is feasible and increases the ease and speed of the procedure: an in vivo study in pigs and first use in human

The HybridKnife water-jet system (ERBE, Tubingen, Germany) has been shown to increase dissection speed and decreased the risk of perforation during endoscopic submucosal dissection (ESD). Glycerol mixture is a viscous, long-lasting solution preferentially used by Japanese ESD experts. The combination of the HybridKnife system with a glycerol solution has not been evaluated to date. A prospective non-randomised comparative study of ESD with HybridKnife injecting of either a glycerol mixture or normal saline was performed. Twenty dissections (ten per group) were performed on four anaesthetised domestic mini-pigs. Dissection speed (mm(2)/min), size of the specimen (mm(2)), duration (min), en bloc resection rate, and bleeding and perforation rates were prospectively recorded. An evaluation of operator comfort and perception of safety (dissection score) was performed using a visual analogue scale with 0 being the worst score and 10 the best. High-pressure injection of the glycerol mixture and dissection with the HybridKnife was feasible without complications. Dissection was significantly more rapid (1.67-fold) with glycerol injection than normal saline injection (27.44 vs. 16.44mm(2)/min; p<0.001). The dissection score was significantly higher in the glycerol group than in the normal saline group (5.9 vs. 2.9; p<0.001). No differences were observed in the rates of en bloc resection, bleeding and perforation. Seven first human cases were also easy without need of preliminary incision and technical complication. High-pressure jet injection of glycerol with HybridKnife for ESD is feasible and increases the speed and safety of the procedure compared with use of normal saline.

How to establish endoscopic submucosal dissection in Western countries.

Endoscopic submucosal dissection (ESD) has been invented in Japan to provide resection for cure of early cancer in the gastrointestinal tract. Professional level of ESD requires excellent staging of early neoplasias with image enhanced endoscopy (IEE) to make correct indications for ESD, and high skills in endoscopic electrosurgical dissection. In Japan, endodiagnostic and endosurgical excellence spread through personal tutoring of skilled endoscopists by the inventors and experts in IEE and ESD. To translocate this expertise to other continents must overcome two fundamental obstacles: (1) inadequate expectations as to the complexity of IEE and ESD; and (2) lack of suitable lesions and master-mentors for ESD trainees. Leading endoscopic mucosal resection-proficient endoscopists must pioneer themselves through the long learning curve to proficient ESD experts. Major referral centers for ESD must arise in Western countries on comparable professional level as in Japan. In the second stage, the upcoming Western experts must commit themselves to teach skilled endoscopists from other referral centers, in order to spread ESD in Western countries. Respect for patients with early gastrointestinal cancer asks for best efforts to learn endoscopic categorization of early neoplasias and skills for ESD based on sustained cooperation with the masters in Japan. The strategy is discussed here.

Tu1427 Postoperative Stricture After Endoscopic Submucosal Dissection for Large Colorectal Tumors

Tu1426 Endoscopic Submucosal Dissection (ESD) of Large Sessile and Flat Neoplastic Lesions in the Colon: a Single-Center Series With 83 Procedures From Europe Malte Sauer, Ralf Hildenbrand, Reinhard Bollmann, Bernd Sido, Franz Ludwig Dumoulin* Dept. of Medicine and Gastroenterology, Gemeinschaftskrankenhaus Bonn, Bonn, Germany; Department of General and Abdominal Surgery, Gemeinschaftskrankenhaus Bonn, Bonn, Germany; Pathology, Institute for Pathology Bonn Duisdorf, Bonn, Germany Introduction: Endoscopic resection of sessile or flat colorectal neoplasia larger than 20mm is usually performed as piecemeal endoscopic mucosal resection (EMR). The disadvantage is the uncertainty of complete resection with reported recurrence rates between 20-30%. In contrast, endoscopic submucosal dissection (ESD) allows en bloc resection of larger sessile or flat lesions. Colorectal ESD is technically demanding and a higher perforation rate has been reported. Currently, there is little experience with this technique in the US and in Europe with only a few series of ESD in the rectum and sigmoid colon and virtually no data on ESD in the proximal colon. The study aimed at the evaluation of efficacy and safety of this method in a western setting. Patients and Methods: Between October 2012 and November 2013 81 consecutive patients were referred for endoscopic treatment of 83 flat neoplastic lesions O 20mm (rectum / sigmoid colon 23%; localization more proximal: 77%; median size 35mm (10-100mm)). ESDs were carried out by a single endoscopist after prior training (animal model, tutorials) with Japanese ESD experts. Procedures were performed using dual knife (Olympus Medical Company, Japan) and VAIO electrosurgical unit (Erbe Elektromedizin, Germany). Results: Mean procedure time was 103 minutes (20-600). Endoscopic en bloc resection rate was 79,5%, histologically confirmed complete resection was achieved in 49,4% of the procedures with high grade intraepithelial neoplasia or early colorectal cancer in 36% of the cases. We observed complications in 10 patients: microperforations (nZ8; 9.6%) which were clipped without relevant clinical consequences and delayed bleedings requiring transfusion (nZ2; 2,4%). Median length of hospital stay was 3 days (1-6 days), the 30 day mortality rate was 0%. The rate of histologically confirmed complete resection increased from 40% for ESD procedures #1-40 to 58% for ESD procedures #41-83 (pZ 0.09). Conclusions: Colorectal ESD is feasible in the western setting with procedure time and complication rates comparable to published series from Asia. The rate of histologically confirmed complete resection needs further improvement.

Desirable training of endoscopic submucosal dissection: further spread worldwide.

Endoscopic submucosal dissection (ESD) is an excellent treatment because of its high curative resection rate and low local recurrence rate. However, its technical difficulty prevents from its permeation worldwide. For further permeation of ESD, the establishment of an appropriate training system is essential. In Japan, trainee endoscopists who have had prerequisites for ESD, that is to say, basic knowledge and skills, start ESD in accordance with a stepwise training system under close supervision by experts. The trainers select an appropriate lesion in human for each step of developments in ESD techniques. In Western countries there are few ESD experts at present, so an ex vivo animal model training must play a major role in the training system. It is desirable that these training systems should be constructed by some authorized organizations such as Japan Gastroenterological Endoscopy Society (JGES).

Prospective, randomized comparison of a prototype endoscope with deflecting working channels versus a conventional double-channel endoscope for rectal endoscopic submucosal dissection in an established experimental simulation model (with video)

A prototype endoscope was designed to improve visualization and dissection of tissue with the use of 2 working channels with different deflections. To evaluate the efficacy and operability of a prototype endoscope in comparison with a conventional double-channel endoscope for rectal endoscopic submucosal dissection (ESD). Randomized, prospective, controlled, ex vivo study. Academic medical center. A total of 80 standardized artificial lesions measuring 3 × 3 cm were created approximately 5 cm from the anal verge in fresh ex vivo porcine colorectal specimens. Two endoscopists each completed 20 cases with the prototype endoscope and 20 cases with the conventional endoscope. An independent observer recorded procedure time, specimen size, en bloc resection, and perforation rate. For the ESD novice, the mean submucosal dissection time (10.5 ± 3.8 vs 14.9 ± 7.3 minutes; P = .024) and total procedure time (18.1 ± 5.2 vs 23.6 ± 8.2 minutes; P = .015) were significantly shorter in the prototype group in comparison with the conventional group. For the ESD expert, there was no significant difference between the mean circumferential resection, submucosal dissection, and total procedure time (prototype group 14.2 ± 6.0 minutes, conventional group 14.2 ± 8.8 minutes; P = .992). The overall perforation and en bloc resection rates were not significantly different between groups. Ex vivo study. In this ex vivo prospective comparison study, there was a technical advantage for the ESD novice with the prototype endoscope that resulted in a shorter procedure time, which was not observed for cases performed by the ESD expert.

Stepwise training in rectal and colonic endoscopic submucosal dissection with differentiated learning curves

Endoscopic submucosal dissection (ESD) has revolutionized the resection of GI superficial neoplasms, but adoption in Western countries is significantly delayed. To evaluate a stepwise colorectal endoscopic submucosal dissection (ESD) learning and operative training protocol. Prospective study in the Western setting. This study took place in a nonacademic hospital with one endoscopist expert in therapeutic endoscopy but novice in ESD. Indications for ESD were superficial neoplasms 20 mm and larger without ulcerations or fibrosis. Training consisted of 5 unsupervised ESDs on isolated stomach, an observation period at an ESD expert Japanese center, 1 supervised ESD on isolated stomach, and retraining on 1 rectal ESD under supervision. The operative training on patients was performed without supervision moving from the rectum to the colon according to the competence achieved. Competence was defined as an 80% en bloc resection rate plus a statistically significant reduction in operating time per square centimeter. Learning curves were calculated based on consecutive blocks of 5 procedures. From February 2009 to February 2012, 30 rectal and 30 colonic ESDs were performed. The rectal ESD learning curve showed that the en bloc resection rate was 80% after 5 procedures (P = not significant); the operating time per square centimeter significantly decreased after 20 procedures (P = .0079); perforation occurred in 1 patient. The colonic ESD learning curve showed that the en bloc resection rate was 80% after 20 procedures (P = not significant); the operating time per square centimeter significantly decreased after 20 procedures (P = .031); perforations occurred in 2 patients. Single-center design. A minimal intensive training seems sufficient for endoscopists expert in therapeutic procedures to take up ESD in a not overly arduous incremental method with separate and sequential learning curves for the rectum and colon.

SAFETY AND EFFICACY OF COLORECTAL ENDOSCOPIC SUBMUCOSAL DISSECTION BY THE TRAINEE ENDOSCOPISTS

The colorectum is known to be the most difficult organ to perform endoscopic submucosal dissection (ESD), however, the training has not been sufficiently established. In our hospital, the essential condition to start colorectal ESD was to experience at least 30 gastric ESD and to have sufficient knowledge and techniques beforehand. Rectal ESD were initially performed under supervision of ESD experts. According to their technical acquisition, the ESD experts allocated lesions to the trainees from smaller lesions in the distal colon to larger lesions in the proximal colon. We retrospectively investigated the outcomes of 92 and 23 colorectal ESD performed by two trainee endoscopists (A/B) who gained experience on our training scheme. The rates of en bloc/complete resection for A and B were 92.4%/73.9% and 95.7%/65.2%, respectively. The rates of bleeding/perforation, which occurred only with A, were 1.1%/3.3%, respectively. Intraoperative perforation occurred in one case (4.3%) in the later period. In the later period, en bloc resection rate remained high in spite of the difficult lesions. Our training scheme enabled trainees to perform colorectal ESD effectively and safely from the initial period. Step-by-step accumulation of cases such as from the rectum to the colon may be desirable for the introduction of colorectal ESD.

TERMINOLOGY FOR TRAINING OF ENDOSCOPIC SUBMUCOSAL DISSECTION

Like many other advanced endoscopic skills, to master the skill of endoscopic submucosal dissection (ESD) requires training for a novice. The general medical terminology should be used similarly even in case of ESD training. However, it is not common for everyone to recall the same meaning from one medical term. Therefore, it is necessary to unify the meaning of medical terms and review their usage in a meeting to achieve a consensus. For this purpose, terms used in the upper gastrointestinal session, Endoscopic Forum Japan 2011, entitled 'Towards further penetration of ESD techniques - what is the role of Japanese ESD experts?', were determined beforehand as shown. Additionally, the present educational approach of ESD in Japan is simply outlined in this article.

Endoscopic Submucosal Dissection (ESD) Training and Performing ESD with Accurate and Safe Techniques

Introduction of endoscopic submucosal dissection (ESD) has brought about a renaissance in therapeutic endoscopy. For the globalization and universalization of ESD, the number of physicians who can perform ESD has rapidly increased with general ex vivo and in vivo training using animal models and hand-on courses. In this focused review series, world-renowned ESD experts described the published studies or their own precious experiences about ESD training and performing ESD with accurate and safe techniques. First, Dr. Adolfo Parra-Blanco reviewed on ex vivo and in vivo models for ESD training. Next, Dr. Joo Young Cho described detailed practical settings and current status of hands-on courses using ex vivo and in vivo models in Korea. Dr. Takashi Toyonaga described quality controlled ESD and basic techniques to prevent complications. Dr. Tsuneo Oyama reviewed recently published methods to facilitate ESD. Dr. Jae-Young Jang reviewed the usefulness of magnifying and narrow band imaging to measure the depth of invasion before ESD.

Training model for teaching endoscopic submucosal dissection of gastric tumors

The elevated risk of complications and technical complexity of endoscopic submucosal dissection (ESD) has limited its implementation in our medical system. To design and evaluate a training program for learning the ESD technique. Four endoscopists with no experience with ESD underwent a 4-step training program: 1) review of the existing literature, didactic material, and theoretical aspects of ESD; 2) ESD training in an ex-vivo animal model; 3) ESD training in an in-vivo animal model (supervised by ESD expert); and 4) ESD performance in a patient. A standard gastroscope and an ESD knife (IT, Flex or Hook-knife Olympus) were employed. The classical ESD technique was performed: rising of the lesion, circumferential incision, and submucosal dissection. Ex-vivo animal model: 6 x swine stomach/esophagus -cost < 100 euro; 6 x ESD: antrum (n = 2), body (n = 3) and fundus/cardia (n = 1)-; size of resected specimen: 4-10 cm; ESD duration: 105-240 minutes; therapeutic success: 100%; complications: perforation (1/6: 16%) sealed with clips. In-vivo animal model: 6 ESD (antrum/body of stomach: 4; esophagus: 2); size: 2-5 cm; duration: 40-165 minutes; success: 100%; complications: 0%. ESD of a gastric lesion located in the antrum/body; size: 3 cm; duration 210 minutes; a complete resection was achieved; no complications. The results of the present study support the usefulness of this model for learning ESD in our system.

Is it possible to predict the procedural time of endoscopic submucosal dissection for early gastric cancer?

Endoscopic submucosal dissection (ESD) has been expected to be a possible curative treatment, especially for node-negative early gastric cancer (EGC). We investigated the influential factors on the procedural time of gastric ESD with a Flex knife for the estimation. In 222 intestinal-type EGC resected by ESD experts with established techniques, age, sex, location, circumference, gross type, tumor size, tumor depth, ulcerative findings, the period of ESD, the operator, and the experience of the operator were retrospectively analyzed. Predictors with a significant difference, as determined by multivariate analysis, were used to compose a predictive formula of procedural time. Location, gross type, tumor depth, ulcerative findings, and tumor size were considered influential factors on the procedural time by univariate analysis. Location in the upper-third of the stomach, presence of ulcerative findings, and > 20 mm in size were independent factors, as determined by multivariate analysis. Procedural time (min) was nearly equal to the maximal tumor size (mm) multiplied by 2.5, and an additional 40 min was required if the tumor was located in the upper-third of the stomach or had ulcerative findings (in both situations, an additional 80 min was needed). The procedural time of ESD with a Flex knife for EGC can be predicted by tumor size, location, and existence of ulcerative findings. The estimation of procedural time may be very useful to determine the operation schedule.

Feasibility of electrocautery snaring as the final step of endoscopic submucosal dissection for stomach epithelial neoplasms

Endoscopic submucosal dissection (ESD) is a novel endoluminal technique that permits the resection of gastric neoplasms. To analyse the feasibility of snaring as the final step of ESD. One hundred and ninety-nine consecutive gastric neoplasms resected by four ESD experts from January 2004 to May 2007 were investigated. Forty-five (22.6%) were finally resected finally using a snare. Rates of en bloc resection, complete (R0 plus en bloc) resection, mean operation time, and complications were assessed between the snaring and the non-snaring groups. En bloc resection rate was significantly lower and delayed bleeding rate was significantly higher in the snaring group than in the non-snaring group (91.1% [41/45] vs. 100% [154/154], 11.1% [5/45] vs. 1.9% [3/154], respectively), although complete resection rate (86.7% [39/45] vs. 92.9% [143/154]) and mean operation time (70.2 min vs. 75.8 min) were not significantly different between the two groups. Six perforation cases (3 [6.7%] in the snaring group, 3 [1.9%] in the non-snaring group) were observed, but snaring did not lead to perforation in any case. When the subjects were divided into small (< or = 2 cm) and large (> 2 cm) tumours, en bloc resection rate in large tumours was still significantly different between the groups (76.9% [10/13] vs. 100% [67/67]), whereas in small tumours it was no longer significantly different (96.9% [31/32] vs. 100% [87/87]). Snaring may facilitate successful ESD for smaller tumours, but multiple-piece resection should be taken into account especially for larger tumours.