Untutored training pathway to achieve competence in esophagogastric endoscopic submucosal dissection in a Western center.

BACKGROUND AND AIMS: Endoscopic submucosal dissection (ESD) has a long learning curve. The aim of this study was to assess the efficacy of an ESD unsupervised training model for experienced endoscopists. METHODS: Stepwise training included a visit to a high-volume center, unsupervised training on an ex vivo porcine model, and in vivo human upper GI cases with anatomic progression. Performance measures included en bloc resection, R0 resection, adverse event rates, and operating time. RESULTS: After observation of 30 esophagogastric ESDs and 15 untutored ex vivo ESDs, 5 human cases of distal gastric ESDs were performed, followed by 55 unselected esophagogastric cases. En bloc and R0 resection rates were 93.0% and 80.7%, respectively. Operating time was 14.0 min/cm2 in the stomach and 25.1 min/cm2 in the esophagus, with evidence of a learning curve for esophageal ESDs (first block 30.26 min/cm2 vs second block 14.81 min/cm2, P = .01). CONCLUSIONS: Untutored training for esophagogastric ESD is feasible and allows endoscopists, experienced in therapeutic endoscopy, to achieve the required standards toward competency.

Intelligent surgical workflow recognition for endoscopic submucosal dissection with real-time animal study.

Recent advancements in artificial intelligence have witnessed human-level performance; however, AI-enabled cognitive assistance for therapeutic procedures has not been fully explored nor pre-clinically validated. Here we propose AI-Endo, an intelligent surgical workflow recognition suit, for endoscopic submucosal dissection (ESD). Our AI-Endo is trained on high-quality ESD cases from an expert endoscopist, covering a decade time expansion and consisting of 201,026 labeled frames. The learned model demonstrates outstanding performance on validation data, including cases from relatively junior endoscopists with various skill levels, procedures conducted with different endoscopy systems and therapeutic skills, and cohorts from international multi-centers. Furthermore, we integrate our AI-Endo with the Olympus endoscopic system and validate the AI-enabled cognitive assistance system with animal studies in live ESD training sessions. Dedicated data analysis from surgical phase recognition results is summarized in an automatically generated report for skill assessment.

Learning curve of endoscopic submucosal dissection (ESD) with prevalence-based indication in unsupervised Western settings: a retrospective multicenter analysis.

BACKGROUND AND AIMS: As there is still no consensus about the adequate training strategy for ESD in Western countries, we evaluated unsupervised prevalence-based learning curves including detailed organ-specific subgroup analysis. METHODS: The first 120 ESDs of four operators (n = 480) were divided into three groups (1: ESD 1-40, 2: ESD 41-80, 3: ESD 81-120). Outcome parameters were rates of technical success, en bloc and R0 resection, the resection speed, rates of conversion to EMR, curative resection, adverse events, surgery due to adverse events, and recurrence. In addition, we analyzed the achievement of quality benchmarks indicating levels of expertise. RESULTS: After exclusion of pretreated lesions, 438 procedures were enrolled in the final analysis. Technical success rates were > 96% with significant improvements regarding rate of en bloc resection (from 82.6 to 91.2%), resection speed (from 4.54 to 7.63 cm2/h), and rate of conversion to EMR (from 22.0 to 8.1%). No significant differences could be observed for rates of R0 resection (65.9 vs. 69.6%), curative resection (55.8 vs. 55.7%), adverse events (16.3 vs. 11.7%), surgery due to adverse events (1.5 vs. 1.3%), and recurrence (12.5 vs. 4.5%). Subgroup and benchmark analysis revealed an improvement in esophageal, gastric, and rectal ESD with achievement of competence levels for the esophagus and stomach within 80 and most of the benchmarks for proficiency level within 120 procedures. Some of the benchmarks could also be achieved in rectal ESD. CONCLUSIONS: This trial confirms safety and feasibility of unsupervised ESD along the initial learning curve with prevalence-based indication and exclusion of colonic cases.

Endoscopic Mucosal Resection and Endoscopic Submucosal Dissection.

Therapeutic endoscopy is an emerging field within general surgery. This article explores the evidence for and usage of endoscopic mucosal resection and endoscopic submucosal dissection throughout the gastrointestinal tract. We aim to educate surgeons and provide an understanding of these techniques. With education and appropriate training, the surgeon will gain confidence and hopefully adopt these tools into their daily practice.

Current status and trend in training for endoscopic submucosal dissection: A nationwide survey in Korea.

BACKGROUND: Although endoscopic submucosal dissection (ESD) is widely used, the current status and trend in its training have yet to be fully evaluated. We aimed to investigate how ESD endoscopists have been trained in actual clinical practice. METHODS: Endoscopists aged <45 years who have completed a gastroenterology fellowship or were currently in a fellowship for ≥2 years were included. We conducted a nationwide survey on the ESD training experiences of these endoscopists. RESULTS: Among 79 young Korean endoscopists invited to participate in the survey, 68 (86.1%) trained in 24 major hospitals responded to the questionnaire. Twenty, 25, and 23 participants belonged to the second-year fellow, <5 years after training, and ≥5 years after training groups, respectively. Sixty-nine percent of the participants observed ≥50 ESD cases before starting ESD under supervision by an expert endoscopist. Additionally, 22% experienced ≥20 supervised ESDs during the training period. The proportion of the participants who underwent a hands-on course differed among the groups (≥5 years after training, 13.0%; <5 years after training, 40.0%; and second-year fellow, 50.0%; P = 0.027). ESD under supervision, observation, and hands-on course were the preferred methods for learning ESD (91.1%, 80.9%, and 35.3%, respectively). Overall, 42.6% of the participants were satisfied with their training program. More experience in supervised ESD (≥20 cases) was associated with an increased satisfaction (odds ratio, 6.65; 95% confidence interval, 1.62-36.31). CONCLUSIONS: Observation and performance of ESD under the supervision of an expert endoscopist are the primary methods for learning ESD. Hands-on course program has been used more frequently in recent years.

Task Deconstruction of Colonic Endoscopic Submucosal Dissection (cESD): An Expert Consensus.

BACKGROUND: Slow adoption of colonic ESD (cESD) in the US is multifactorial due to: lack of clinical training construct (e.g., gastric ESD in Japan), complication risks, and technical difficulty. More than 28,000 patients/year undergo colonic resection for benign lesions that could be managed effectively with cESD. Selected patients could avoid surgery if procedural adoption of cESD increased due to more accessible training. Current US cESD training is scarce, and existing programs are piecemeal. There is a need to develop an effective national training program for practicing endoscopists. A prerequisite to training development is a comprehensive task list delineating procedural steps. The aim of this work was to describe an evidence-based method of deconstructing cESD into the essential steps to provide a task list to guide teaching and assessment. METHODS: Subject-matter experts (SMEs) performed a literature review to create an initial procedural step list. Eleven clinical cESD SMEs and four educational SMEs formed a 'cESD Working Group' to develop consensus regarding steps. Through a two-stage modified Delphi process, a consensus on a comprehensive standard cESD deconstructed task list was reached. The aim was to standardize cESD teaching to efficiently bring a novice to safe performance. RESULTS: A literature review identified eight initial cESD steps. First-round Delphi consensus was gained on seven steps. Semi-structured focus group discussions resulted in consensus on a modified version of 7 of the initial steps, with addition of two steps. Consensus on procedural actions needed to perform each step was achieved after the hands-on laboratory. The final result was a ten-step deconstructed task list for standard cESD. CONCLUSION: The development of a standardized cESD procedural task list provides a foundation to safely and efficiently teach cESD to practicing endoscopists. This list can be used to develop a training pathway to increase procedural adoption. Selected patients currently undergoing colonic resections could benefit from increased adoption of cESD.

Efficacy of traction, using a clip-with-thread, for esophageal endoscopic submucosal dissection for esophageal lesions with fibrosis in an ex vivo pig training model.

BACKGROUND/AIMS: Endoscopic submucosal dissection (ESD) of recurrent esophageal carcinoma is technically difficult to perform due to submucosal fibrosis that develops after definitive chemoradiation therapy. Therefore, our aim was to evaluate the usefulness of clip-with-thread traction for ESD of esophageal lesions with submucosal fibrosis. MATERIALS AND METHODS: Four endoscopists excised 16 lesions by ESD in an ex vivo pig training model. Mock lesions (30 mm in diameter) were created, including a 10-mm area of submucosal fibrosis in the center of each lesion. Each endoscopist performed two ESDs with traction (ESD-T) and two without traction (ESD-N). The primary outcome was the time required for submucosal dissection. Secondary outcomes were the rate of en bloc (complete) resection and perforation during the procedure, and the total amount of solution injected. RESULTS: All esophageal ESDs were completed. The median dissection time was significantly shorter for the ESD-T group (median 12.5 min, interquartile range 10.2-14.5) when comparing to the ESD-N group (median 18.0 min, interquartile range 14.6-19.2) (P=0.040). The en bloc resection rate was 100% in both groups, with a rate of complete resection of 87.5% and a rate of perforation of 37.5% for both groups. The median amount of solution injected was not significantly different between the ESD-T (18.0 ml) and ESD-N (20.5 ml) groups (P=0.526). CONCLUSION: Clip-with-thread traction improved the performance of ESD for lesions with submucosal fibrosis. However, the method might not reduce the risk of perforation, which remains an important clinical issue to resolve.

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

BACKGROUND/AIMS: 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. METHODS: 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. RESULTS: 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 44.5 mm, 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. CONCLUSIONS: 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.

How to Learn and Perform Endoscopic Submucosal Dissection and Full-Thickness Resection in the Colorectum in the United States.

Pioneered in Japan to address the limitations of endoscopic mucosal resection in the stomach, endoscopic submucosal dissection (ESD) has been applied throughout the gastrointestinal tract, including the colorectum. ESD is technically challenging and has been slowly gaining traction in the West. However, for the committed and resourceful endoscopist, proficiency in ESD can still be achieved. Moreover, improvement in techniques and devices are likely to ease the learning curve while improving procedural duration, safety, and efficacy of colorectal ESD. This article reviews challenges and methods in learning ESD in the United States and provides a primer on performing ESD and full-thickness resection in the colorectum.

[The animal models using live pigs in the application and development of endoscopic submucosal dissection training].

Endoscopic submucosal dissection (ESD) is the gold standard technique for performing en bloc resection of large superficial tumors in the upper and lower gastrointestinal tract. It has not started in China until early 2006, when it was introduced at Endoscopy Center of Zhongshan Hospital. However, ESD is technically more difficult and can result in more complications, limiting its development in China. At present, reports about ESD training system in China are still not available. Therefore, our center continuously explored and gradually established structured training courses relied on the live pig model. Between 2009 and 2013, we held 23 hands-on ESD training workshops with 550 endoscopists. Questionnaires were distributed via e-mail, and there were 460 participants performing ESD in a step-up approach on the live pigs. More than one half of trainees could perform ESD with en bloc resection in the imaginary "lesion" of colon and stomach, and there were higher rates of hemorrhage and perforation occurring in colorectal ESD as compared to gastric ESD. After graduating from our hands-on workshop, up to over 90% of participants started ESD practice in their home hospitals. It was mostly provided by high-grade hospitals (IIIA) which played a major role as tertiary referral centers, covering almost all provinces and major cities in China. The training on live pig model revealed to be safe and effective as a prior step to its application in humans. It may enable novice endoscopists to acquire ESD skills and start performing ESD as soon as possible. The role of adequate training is of course to influence the spread of this technique and promote ESD development around China.

Suture pulley countertraction method reduces procedure time and technical demand of endoscopic submucosal dissection among novice endoscopists learning endoscopic submucosal dissection: a prospective randomized ex vivo study.

BACKGROUND AND AIMS: The lack of reliable countertraction in endoscopic submucosal dissection (ESD) contributes to its technical demand and increased procedure time. We aimed to prospectively evaluate the efficacy of the suture pulley countertraction method in endoscopists new to both suturing and ESD. METHODS: Two 30-mm circular lesions were created in an ex vivo porcine stomach model. Endoscopists considered novices for both endoscopic suturing and ESD were randomized to either traditional or suture pulley ESD first and performed ESD using each technique. Procedure time was recorded including time of circumferential incision, suture pulley placement, and submucosal dissection. After completion of each ESD, participants graded the difficulty of the procedure using the National Aeronautical and Space Administration (NASA) Task Load Index. RESULTS: Thirteen participants (8 fellows, 5 attendings) completed the study using both methods. Mean total procedure time was shorter using suture pulley ESD compared with traditional ESD (26.7 ± 7.3 vs 59.4 ± 20.4 minutes, P < .001). The suture pulley required a mean 6.2 ± 2.1 minutes to place. Submucosal dissection time was shorter using suture pulley ESD compared with traditional ESD (8.4 ± 2.9 vs 47.2 ± 16.3 minutes, P < .001). All 7 individual indices and total score on the NASA Task Load Index were significantly improved using the suture pulley ESD method (P < .001). CONCLUSIONS: The suture pulley countertraction method significantly decreases procedure time and technical demand of ESD among endoscopists at all skill levels who are new to ESD. The results of this study have potential implications for ESD training in the United States.

A task and performance analysis of endoscopic submucosal dissection (ESD) surgery.

BACKGROUND: ESD is an endoscopic technique for en bloc resection of gastrointestinal lesions. ESD is a widely-used in Japan and throughout Asia, but not as prevalent in Europe or the US. The procedure is technically challenging and has higher adverse events (bleeding, perforation) compared to endoscopic mucosal resection. Inadequate training platforms and lack of established training curricula have restricted its wide acceptance in the US. Thus, we aim to develop a Virtual Endoluminal Surgery Simulator (VESS) for objective ESD training and assessment. In this work, we performed task and performance analysis of ESD surgeries. METHODS: We performed a detailed colorectal ESD task analysis and identified the critical ESD steps for lesion identification, marking, injection, circumferential cutting, dissection, intraprocedural complication management, and post-procedure examination. We constructed a hierarchical task tree that elaborates the order of tasks in these steps. Furthermore, we developed quantitative ESD performance metrics. We measured task times and scores of 16 ESD surgeries performed by four different endoscopic surgeons. RESULTS: The average time of the marking, injection, and circumferential cutting phases are 203.4 (σ: 205.46), 83.5 (σ: 49.92), 908.4 s. (σ: 584.53), respectively. Cutting the submucosal layer takes most of the time of overall ESD procedure time with an average of 1394.7 s (σ: 908.43). We also performed correlation analysis (Pearson's test) among the performance scores of the tasks. There is a moderate positive correlation (R = 0.528, p = 0.0355) between marking scores and total scores, a strong positive correlation (R = 0.7879, p = 0.0003) between circumferential cutting and submucosal dissection and total scores. Similarly, we noted a strong positive correlation (R = 0.7095, p = 0.0021) between circumferential cutting and submucosal dissection and marking scores. CONCLUSIONS: We elaborated ESD tasks and developed quantitative performance metrics used in analysis of actual surgery performance. These ESD metrics will be used in future validation studies of our VESS simulator.

Competency assessment for gastric endoscopic submucosal dissection using an endoscopic part-task training box.

BACKGROUND: Objective assessment of endoscopist competency is important. Recently, the endoscopic part-task training box (Thompson Endoscopic Skills Trainer [TEST]) was developed to assess endoscopist competency. We aimed to evaluate the ability of the TEST to assess competency during endoscopic procedures, especially endoscopic submucosal dissection (ESD). METHODS: Twenty-three physicians were included in this study. Correlations between TEST scores and the following factors were evaluated: years of endoscopic experience, number of esophagogastroduodenoscopies (EGDs) performed, number of colonoscopies (CSs) performed, cecal intubation rate, number of gastric ESDs performed, gastric ESD procedure time/lesion size (min/mm2), and gastric ESD self-completion rate. Also, correlation coefficients between the number of gastric ESDs performed and each of gastric ESD procedure time/lesion size and gastric ESD self-completion rate were calculated. RESULTS: TEST scores showed strong correlations to different factors: years of experience in endoscopy: 0.957 (p < 0.01); number of EGDs: 0.947 (p < 0.01); number of CSs: 0.947, (p < 0.01); number of gastric ESDs: 0.924 (p < 0.01); gastric ESD procedure time/lesion size: - 0.9 (p < 0.01); self-completion rate of gastric ESDs: 0.857 (p < 0.005). The number of gastric ESDs performed was not more strongly correlated to procedure time of gastric ESDs or self-completion rate of gastric ESDs compared to TEST scores (- 0.824 (p < 0.01) and 0.704 (p < 0.05), respectively). TEST scores of endoscopists with a cecal intubation rate ≥ 90% were > 380, while the scores of physicians with a gastric ESD self-completion rate ≥ 90% were > 700. CONCLUSIONS: TEST score correlates with both basic and advanced endoscopic procedures. TEST is therefore a promising option for assessing endoscopist competency, and might be useful for providing threshold scores as competency markers for specific endoscopic procedures such as gastric ESD.

Comparison of Endoscopic Submucosal Dissection for Primary and Recurrent Colorectal Lesions: A Single-Center European Study.

INTRODUCTION: Endoscopic submucosal dissection (ESD) is an acknowledged endoscopic technique for the management of early gastrointestinal neoplasia. The clinical experience and the research from the Eastern ESD centers show that experienced endoscopists can successfully treat even the most demanding recurrent colorectal lesions. AIM: The aim of this study was to analyze the clinical outcomes of the management of recurrent colorectal lesions in comparison with those of primary lesions in the setting of high-volume European center. METHODS: A retrospective analysis of 298 cases (228 primary lesions and 70 recurrent lesions) performed by a single endoscopist was carried out. Evaluating learning curves for both primary and recurrent lesions, cumulative sum analysis was performed. RESULTS: Primary lesions had ∼9% higher R0 resection rate (86.84% versus 78.51%). Yet, this difference did not reach statistical significance (P = .091). The presence of recurrent lesion and lengthy procedure (≥150 min) are risks factors of R1 resection, whereas rectal localization of the lesion was associated with lower risk of R1 resection. The cumulative R0 of 80% was achieved at 36th procedure in the primary lesions group, whereas for the recurrent lesions it was reached at 50th procedure (overall 229 procedures). CONCLUSIONS: Our study underlines the importance of proper experience in ESD before the management of recurrent lesions. Even after the completion of high volume of primary lesions, first recurrent lesions can pose a challenge. Nevertheless, the final outcomes are promising, as the complications do not pose a serious risk to the patients and high R0 resection rate can be achieved in a reasonable timeframe.

How to master endoscopic submucosal dissection in the USA.

Endoscopic submucosal dissection (ESD) is an established technique for the endoscopic therapy of dysplastic and early cancerous lesions throughout the gastrointestinal tract. The procedure requires both a sophisticated knowledge for lesion characterization and high-level endoscopic skills. As a result, the learning curve is very steep and, in Japan, it takes years to gain proficiency under the traditional Master-Apprentice teaching model. At present, as a result of multiple limitations, this training model is not applicable to the USA. Nevertheless, a unique, multipronged, stepwise approach has emerged as a viable pathway to train US endoscopists in ESD. Although this approach deserves refinement, it has already led to the expansion of ESD in the USA, has contributed to the widening of the indications for ESD, and has further developed ESD techniques. Multiple challenges remain, but they can be overcome by active collaboration between Japanese and US endoscopists and professional societies. The robust interest in ESD in the USA has drawn industry attention with a few innovations already coming to fruition and many more in development.

USEFULNESS OF GASTRIC SUBMUCOSAL DISSECTION DEPTH TO EVALUATE SKILL ACQUIREMENT IN SHORT TERM TRAINING COURSES IN ESD: AN EXPERIMENTAL STUDY.

BACKGROUND: Endoscopic submucosal dissection (ESD) is a complex endoscopic procedure, with high rates of adverse events and technical difficulties. To overcome that problem, many training centers published the importance of animal models for skill acquirement in ESD. However, no study has used the submucosal dissection depth (DSUB) as a parameter to evaluate the learning curve in ESD, which might be a relevant factor since an optimal resection plane is important to achieve a curative resection and avoid intraoperative complications. OBJECTIVE: This study aimed to assess ESD skill acquirement after short-term training sessions by evaluating the submucosal dissection depth (DSUB) and the association with adverse events. METHODS: This experimental study included 25 experienced endoscopists in therapeuthic procedures (>5years) and 75 specimens resected by ESD (three resections / endoscopist). Learning parameters (resection time, size, en bloc resection rate, bleeding, perforation and submucosal dissection depth) were prospectively evaluated. The percentages of DSUB of all specimens resected were calculated. RESULTS: All specimens were resected from the gastric body (n=75). The mean size of the resected specimens was 23.97±7.2 mm. The number of adverse events, including bleeding, perforation, and death, were 17 (22.67%), 3 (4%), and 0 cases, respectively. The average mean time by the third dissection decreased from 28.44±9.73 to 18.72±8.81 min (P<0.001). The proportion of DSUB in the bleeding and non-bleeding group were respectively 37.97%±21.13% and 68.66%±23.99%, indicating a significant association between DSUB and bleeding incidence (P<0.001). The ROC curve analysis indicated a cut-off point of 61% (sensitivity, 64%; specificity, 94%) of submucosal dissection depth associated with bleeding. Therefore, when ESD was performed at a depth of >61% of the submucosal layer, the risk for bleeding during the procedure decreased (PPV, 0.97; 95% CI, 0.85-0.99). CONCLUSION: Improvement in the learning curve in ESD and a better cognitive ability were seen by the third dissection in these short term training courses. And a significant association between DSUB and the risk of bleeding.

Implementation of mentor-assisted colorectal endoscopic submucosal dissection in Sweden; learning curve and clinical outcomes.

OBJECTIVE: It's still challenging to introduce colorectal (CR) ESD in Western countries. We assessed the feasibility of introducing and implementing CR-ESD in Sweden with hiring Japanese expert as a supervisor. METHODS: We analyzed 71 consecutive CR-ESD cases performed by two endoscopists who had no (endoscopist A (E-A)) or 20 cases (endoscopist B (E-B)) of experience in ESD. E-A performed rectal lesions while E-B performed lesions in any locations. Factors associated with failure in en bloc resection and in self-accomplishment were analyzed. RESULTS: Overall en bloc and R0 resection rates were 80.3% and 70.4%. Adverse event occurred in 7.0% including two perforations, two post-operative hemorrhage and one delayed perforation. Only case with delayed perforation underwent surgical treatment. Total self-accomplishment rate was 50% (10/20) for E-A, and 37.3% (19/51) for E-B. Dividing each performer's cases into three learning phases, self-accomplishment rates increased from 42.9% to 83.3% for E-A, and from 29.4% to 70.6% for E-B, as well as en bloc resection rates from 71.4% to 100% for E-A, and from 52.9% to 94.1% for E-B. Multivariate analysis revealed that location upper than rectum, lesions with formerly taken biopsy and lesions larger than 30mm were significantly associated with en bloc resection failure. CONCLUSIONS: Implementation of CR-ESD with hiring Japanese supervisor for certain period was safe for patients and effective for good learning curve.

A aplicação da profundidade de dissecção da submucosa gástrica na avaliação do aprendizado em ESD: um estudo experimental / Usefulness of gastric submucosal dissection depth to evaluate skill acquirement in short term training courses in esd: an experimental study

ABSTRACT BACKGROUND: Endoscopic submucosal dissection (ESD) is a complex endoscopic procedure, with high rates of adverse events and technical difficulties. To overcome that problem, many training centers published the importance of animal models for skill acquirement in ESD. However, no study has used the submucosal dissection depth (DSUB) as a parameter to evaluate the learning curve in ESD, which might be a relevant factor since an optimal resection plane is important to achieve a curative resection and avoid intraoperative complications. OBJECTIVE: This study aimed to assess ESD skill acquirement after short-term training sessions by evaluating the submucosal dissection depth (DSUB) and the association with adverse events. METHODS: This experimental study included 25 experienced endoscopists in therapeuthic procedures (>5years) and 75 specimens resected by ESD (three resections / endoscopist). Learning parameters (resection time, size, en bloc resection rate, bleeding, perforation and submucosal dissection depth) were prospectively evaluated. The percentages of DSUB of all specimens resected were calculated. RESULTS: All specimens were resected from the gastric body (n=75). The mean size of the resected specimens was 23.97±7.2 mm. The number of adverse events, including bleeding, perforation, and death, were 17 (22.67%), 3 (4%), and 0 cases, respectively. The average mean time by the third dissection decreased from 28.44±9.73 to 18.72±8.81 min (P<0.001). The proportion of DSUB in the bleeding and non-bleeding group were respectively 37.97%±21.13% and 68.66%±23.99%, indicating a significant association between DSUB and bleeding incidence (P<0.001). The ROC curve analysis indicated a cut-off point of 61% (sensitivity, 64%; specificity, 94%) of submucosal dissection depth associated with bleeding. Therefore, when ESD was performed at a depth of >61% of the submucosal layer, the risk for bleeding during the procedure decreased (PPV, 0.97; 95% CI, 0.85-0.99). CONCLUSION: Improvement in the learning curve in ESD and a better cognitive ability were seen by the third dissection in these short term training courses. And a significant association between DSUB and the risk of bleeding.

RESUMO CONTEXTO: A técnica de ESD (Endoscopic Submucosal Dissection) é um procedimento endoscópico de grande complexidade, com alto índice de complicações e dificuldades técnicas. Para superar este problema, muitos centros de treinamento em endoscopia vêm publicando a aplicabilidade dos modelos animais para a aquisição de competência em ESD. Entretanto, a profundidade de ressecção nunca foi utilizada como parâmetro de aprendizagem, o que pode ser um fator relevante a ser ensinado, dado que atingir o plano de dissecção ideal é de suma importância para uma ressecção curativa e na prevenção de complicações intraoperatórias. OBJETIVO: Analisar o aprendizado em ESD em treinamentos de curta duração através da avaliação da profundidade de submucosa ressecada; e sua associação com complicações. MÉTODOS: Estudo experimental; incluídos 25 endoscopistas com experiência em procedimentos terapêuticos (> 5anos) e 75 peças ressecadas por ESD sendo uma média de três resseções por endoscopista. Os parâmetros de aprendizagem (tempo de ressecção, tamanho, taxa de ressecção em bloco, sangramento, perfuração e análise histológica da camada submucosa) foram prospectivamente avaliados. A percentagem de profundidade de submucosa ressecada foi calculada. RESULTADOS: Todas as ressecções foram realizadas no corpo gástrico (n=75). O tamanho médio das peças ressecadas foi de 23,97±7,2 mm. O número de complicações como sangramento, perfuração e morte foram respectivamente, 17 (22,67%), 3 (4%) e 0 casos. Na terceira dissecção, tempo médio do procedimento diminuiu de 28,44±9,73 para 18,72±8,81 minutos (P<0,001). O grupo que teve sangramento durante o procedimento ressecou 37,97%±21,13% da camada submucosa e o grupo sem sangramento ressecou 68,66%±23,99%, demonstrando uma associação significante entre a profundidade de dissecção submucosa e a incidência de sangramento (P<0,001). De acordo com a análise de curva ROC, o valor de corte da profundidade de submucosa ressecada para a ocorrência de sangramento é de 61% (64% sensibilidade, 94% especificidade), logo quando o ESD é realizado em uma profundidade maior do que 61% da camada submucosa o risco de sangramento durante o procedimento diminui (VPP=0,97; IC95%:0,85-0,99). CONCLUSÃO: O modelo de treinamento de curta duração possibilitou um aprendizado da técnica de ESD mostrando uma melhora cognitiva dos alunos já na terceira dissecção. Existe uma associação significativa entre a profundidade de ressecção da submucosa com o risco de sangramento.