In vitro porcine training model for colonic endoscopic submucosal dissection: an inexpensive and safe way to acquire a complex endoscopic technique. Surg Endosc. 2010;24:2439-2443. [PMID: 20333407 DOI: 10.1007/s00464-010-0982-5]

Safe and Efficient Procedures and Training System for Endoscopic Submucosal Dissection

Recent improvements in endoscopists' skills and technological advances have allowed endoscopic submucosal dissection (ESD) to become a standard treatment in general hospitals. As this treatment entails a high risk of accidental perforation or hemorrhage, therapeutic procedures and training methods that enable ESD to be conducted more safely and efficiently are constantly being developed. This article reviews the therapeutic procedures and training methods used to improve the safety and efficiency of ESD and describes the ESD training system used in a Japanese university hospital at which the number of ESD procedures has gradually increased in a newly established Department of Digestive Endoscopy. During the establishment of this department, the ESD perforation rate was zero among all procedures, including those conducted by trainees.

Endoscopic resection of superficial bowel neoplasia: The unmet needs in the Egyptian practice

BACKGROUND

Management of superficial bowel neoplasia (SBN) in early stages is associated with better outcomes. The last few decades experienced a paradigm shift in the management of SBN with the introduction of advanced endoscopic resection techniques (ERTs). However, there are no clear data about the aspects of ERTs in Egypt despite the growing gastroenterology practice.

AIM

To investigate the knowledge, attitude, and practice of ERTs toward management of SBN among Egyptian practitioners and the suitability of the endoscopy units’ infrastructures toward these techniques.

METHODS

An online 2-pages questionnaire was used. The first page comprised demographic data, and questions for all physicians, about the knowledge (11 questions) of and attitude (5 questions) toward ERTs as a therapeutic option for SBN. The second page investigated the practice of ERTs by endoscopists (6 questions) and the infrastructures of their endoscopy units (14 questions). The survey was disseminated through July 2021 and the data were collected in an excel sheet and later analyzed anonymously.

RESULTS

The complete responses were 833/2300 (36.2%). The majority of the participants were males (n = 560, 67.2%), middle-aged (n = 366, 43.9%), consultants (n = 464, 55.7%), gastroenterologists (n = 678, 81.4%), spending ≥ 15 years in practice (n = 368, 44.2%), and were working in university hospitals (n = 569, 68.3%). The majority correctly identified the definition of SBN (88.4%) and the terms polypectomy, endoscopic mucosal resection (EMR), and endoscopic submucosal dissection (ESD) (92.1%, 90.2%, and 89.1% respectively). However, 26.9%, 43.2% and 49.5% did not recognize the clear indication of polypectomy, EMR, and ESD respectively. Although 68.1% of physicians are convinced about the ERTs for management of SBN; only 8.9% referred all candidate cases for ERTs. About 76.5% of endoscopists had formal training in the basic polypectomy techniques while formal training for EMR and ESD was encountered only in 31.9% and 7.2% respectively. About 71.6% and 88.4% of endoscopists did not perform EMR or ESD in the last one year. Consequently, the complication rate reported by endoscopists was limited to 18.1% (n = 103) of endoscopists. Only 25.8% of endoscopists feel confident in the management of ERTs-related complications and a half (49.9%) were not sure about their competency. Regarding the endoscopy units’ infrastructures, only 4.2% of the centers had their endoscopes 100% armed with optical enhancements and 54.4% considered their institutions ready for managing ERTs-related complications. Only 18.3% (n = 104) of endoscopists treated their complicated cases surgically because the most frequent ERTs-related complications were procedural bleeding (26.7%), and perforations (17%).

CONCLUSION

A significant deficiency was reported in the knowledge and attitude of Egyptian practitioners caring for patients with SBN toward ERTs. The lack of trained endoscopists in both EMR and ESD in part is due to unsuitable infrastructures of many endoscopy units.

Endoscopic resection of superficial bowel neoplasia: The unmet needs in the Egyptian practice

BACKGROUND

Management of superficial bowel neoplasia (SBN) in early stages is associated with better outcomes. The last few decades experienced a paradigm shift in the management of SBN with the introduction of advanced endoscopic resection techniques (ERTs). However, there are no clear data about the aspects of ERTs in Egypt despite the growing gastroenterology practice.

AIM

To investigate the knowledge, attitude, and practice of ERTs toward management of SBN among Egyptian practitioners and the suitability of the endoscopy units’ infrastructures toward these techniques.

METHODS

An online 2-pages questionnaire was used. The first page comprised demographic data, and questions for all physicians, about the knowledge (11 questions) of and attitude (5 questions) toward ERTs as a therapeutic option for SBN. The second page investigated the practice of ERTs by endoscopists (6 questions) and the infrastructures of their endoscopy units (14 questions). The survey was disseminated through July 2021 and the data were collected in an excel sheet and later analyzed anonymously.

RESULTS

The complete responses were 833/2300 (36.2%). The majority of the participants were males (n = 560, 67.2%), middle-aged (n = 366, 43.9%), consultants (n = 464, 55.7%), gastroenterologists (n = 678, 81.4%), spending ≥ 15 years in practice (n = 368, 44.2%), and were working in university hospitals (n = 569, 68.3%). The majority correctly identified the definition of SBN (88.4%) and the terms polypectomy, endoscopic mucosal resection (EMR), and endoscopic submucosal dissection (ESD) (92.1%, 90.2%, and 89.1% respectively). However, 26.9%, 43.2% and 49.5% did not recognize the clear indication of polypectomy, EMR, and ESD respectively. Although 68.1% of physicians are convinced about the ERTs for management of SBN; only 8.9% referred all candidate cases for ERTs. About 76.5% of endoscopists had formal training in the basic polypectomy techniques while formal training for EMR and ESD was encountered only in 31.9% and 7.2% respectively. About 71.6% and 88.4% of endoscopists did not perform EMR or ESD in the last one year. Consequently, the complication rate reported by endoscopists was limited to 18.1% (n = 103) of endoscopists. Only 25.8% of endoscopists feel confident in the management of ERTs-related complications and a half (49.9%) were not sure about their competency. Regarding the endoscopy units’ infrastructures, only 4.2% of the centers had their endoscopes 100% armed with optical enhancements and 54.4% considered their institutions ready for managing ERTs-related complications. Only 18.3% (n = 104) of endoscopists treated their complicated cases surgically because the most frequent ERTs-related complications were procedural bleeding (26.7%), and perforations (17%).

CONCLUSION

A significant deficiency was reported in the knowledge and attitude of Egyptian practitioners caring for patients with SBN toward ERTs. The lack of trained endoscopists in both EMR and ESD in part is due to unsuitable infrastructures of many endoscopy units.

Comparison of sodium alginate-based and sodium hyaluronate-based submucosal injection materials based on rheological analysis

As a viscous high-performance submucosal injection material (SIM) used in endoscopic submucosal dissection (ESD), sodium alginate-based SIM (SA-SIM) was recently introduced as high-performance SIM equivalent to sodium hyaluronate-based SIM (HA-SIM) in Japan. However, a comprehensive, detailed comparison of SA and HA is yet to be performed. In this study, we precisely measured the viscoelastic properties, submucosal elevation height (SEH), and injection pressure (IP). Furthermore, we compared the outcomes of ESD using an ex vivo ESD model. There was no significant difference in SEHs between HA-SIM and SA-SIM at all post-injection times, and the IP of the SA-SIM injection was significantly higher than that of the HA-SIM injection in all conditions (P < 0.0001). The viscosity at high shear rates of SA-SIM was higher than that of HA-SIM; this result was consistent with SEH/IP measurement results. No significant difference was observed in ESD procedure time and total volume of injected SIM between HA-SIM and SA-SIM (18.1 ± 6.7 and 17.8 ± 6.0 min, P = 0.8987; 13.3 ± 5.3 and 11.6 ± 5.9 ml, P = 0.4658, respectively). Although SA-SIM was slightly more difficult to inject than HA-SIM, there was no significant difference in performance between the materials. Thus, this basic study demonstrated that SA-SIM can be used for endoscopic treatment as well as HA-SIM, and supported previous clinical research data.

Differences between two sodium hyaluronate-based submucosal injection materials currently used in Japan based on viscosity analysis

In Japan, two 0.4% sodium hyaluronate (HA)-based submucosal injection materials (SIMs) are currently used in endoscopic submucosal dissection (ESD): MucoUp (HA-Mc) and Ksmart (HA-Ks). HA-Mc and HA-Ks have the same concentration and are, thus, construed by most endoscopists to have no difference. Nevertheless, visual observation conveys the impression that HA-Ks have a higher viscosity than HA-Mc, suggesting that HA-Ks performs better than HA-Mc. This study aimed to examine the differences between HA-Mc and HA-Ks. HA-Ks exhibited higher viscosity due to greater weight-average molecular weight compared with HA-Mc. HA-Ks had significantly greater submucosal elevation height (SEH) than HA-Mc; the SEH of HA-Ks-80% (80% dilution of HA-Ks) was the same as that of HA-Mc. The ESD procedure time was significantly shorter with HA-Ks than with HA-Mc (15.2 ± 4.1 vs. 19.5 ± 5.9; P = 0.049). The total injection volume for HA-Ks was significantly lower than that for HA-Mc (10.8 ± 3.6 vs. 14.4 ± 4.6; P = 0.045). However, no significant difference in these items was observed between HA-Mc and HA-Ks-80%. HA-Mc and HA-Ks were considered to be almost the same. Nonetheless, HA-Ks exhibited higher viscosity and SIM performance than HA-Mc. HA-Ks-80% had almost the same performance as HA-Mc. Thus, understanding SIM performance and characteristics requires a focus on the viscosity of SIMs.

An innovative next-generation endoscopic submucosal injection material with a 2-step injection system (with video)

BACKGROUND AND AIMS

Next-generation submucosal injection materials (SIMs) with higher performance and flexibility than the current SIMs (eg, 0.4% sodium hyaluronate solution [HA]) are expected to improve the outcomes of endoscopic submucosal dissection (ESD) but are difficult to develop. We developed a next-generation SIM by devising a 2-solution-type SIM comprising 2.0% calcium chloride solution (Ca) and 0.4% sodium alginate solution (SA) and evaluated its performance.

METHODS

Viscoelasticity, submucosal elevation height, and injection pressure of HA, SA, and the next-generation SIM were measured. Outcomes of ESDs on pseudo-lesions in ex vivo porcine stomach/colon models were compared.

RESULTS

The dramatic increase in SA viscoelasticity with the addition of Ca facilitated the formation of highly viscous submucosal cushions that can be controlled by endoscopists. The submucosal elevation height of the next-generation SIM was significantly higher than that of HA or SA with the same injection pressure. The ESD procedure time using the next-generation SIM was significantly shorter than that using HA or SA (14.2 ± 6.1 vs 29.2 ± 9.1 minutes, P = .0004, or 14.2 ± 6.1 vs 29.1 ± 5.9 minutes, P <.0001). Furthermore, the total injection volume for the next-generation SIM was considerably lower than that for HA or SA (7.0 ± 0.9 vs 17.2 ± 3.4 mL, P <.0001, or 7.0 ± 0.9 vs 16.2 ± 2.9 mL, P <.0001).

CONCLUSIONS

We developed an ideal next-generation SIM that achieved high performance and high flexibility in ex vivo models. Our findings warrant further investigations in a patient population.

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.

Review on colorectal endoscopic submucosal dissection focusing on the technical aspect

BACKGROUND

Endoscopic submucosal dissection (ESD) enables removal of broad-based colorectal polyps or lateral spreading tumors with a higher rate of en bloc resection and a lower risk of local recurrence. However, it is technically demanding. Over the past 20 years, various equipment and innovative techniques have been developed to reduce the difficulty of ESD. The information in the literature is scattered. Our aim is to provide a comprehensive review on the setup and technical aspects of colorectal ESD.

METHODS

We searched the PubMed database and systemically reviewed all original and review articles related to colorectal ESD. Further manual search according to reference lists of identified articles were done. The selected articles were categorized and reviewed. Original figures were created to help readers understand some of the ESD techniques.

RESULTS

A total of 216 articles were identified, in which 25 of them were review articles and 191 of them were original articles. They were categorized and reviewed. An in-depth appraisal of the setting, equipment, and technical aspects of colorectal ESD was performed.

CONCLUSIONS

Although ESD is a technically demanding procedure that requires expert endoscopic skills, it can be mastered. With good peri-procedural preparation, sufficient knowledge of the equipment, and thorough understanding of the useful endoscopic tricks and maneuvers, colorectal ESD can be performed smoothly and safely.

Construction of a preoperative scoring system to predict the difficulty level of colorectal endoscopic submucosal dissection

Background

We attempted to examine the factors contributing to the difficulty in performance of colorectal ESD, with the aim of constructing a scoring system that could help in prediction of the difficulty level of the procedure.

Methods and materials

The data were analyzed from two viewpoints: to determine the factors contributing to 1) non-en bloc resection and the factors contributing to 2) a slow resection speed. Factors falling under these two categories contributing to difficulty in performance of ESD were extracted and used to construct a scoring system. The validity of this scoring system was evaluated by calculating the correlation between the score and the resection speed in a different dataset.

Results

Based on the results of our analysis, we assigned scores for various factors as follows: 4 points for EMR of a scarred lesion, 1 point for tumors with a diameter of ≥ 30 mm, 2 points for lesions located in the liver/splenic flexure, 1 point for lesions located in the transverse colon, 3 points for LST-NG-PD/depressed lesions, 1 point for protruded lesions and LST-NG-F lesions (range 0–10). In the validation study, the rank correlation coefficient between the score according to the scoring system and the resection speed was -0.130, representing a weak and negative correlation (P = 0.03). We defined the difficulty level depending on the sum of the scores: 0–2, low difficulty level; 3–5, intermediate difficulty level; ≥ 6, high difficulty level. The average resection speed was 12.6 mm²/min in the group with scores of 0–2, 8.1 mm²/min in the group with scores of 3–5, and 5.5 mm²/min in the group with scores of ≥ 6 (11.2 mm²/min in all lesions).

Conclusion

Our colorectal ESD scoring system would be useful for selection of operators with the appropriate skill level in the procedure for colorectal ESD cases.

Endoscopic submucosal dissection: a cognitive task analysis framework toward training design

BACKGROUND

One of the major impediments to the proliferation of endoscopic submucosal dissection (ESD) training in Western countries is the lack of sufficient experts as instructors. One way to address this gap is to develop didactic systems, such as surgical simulators, to support the role of trainers. Cognitive task analysis (CTA) has been used in healthcare for the design and improvement of surgical training programs, and therefore can potentially be used for design of similar systems for ESD.

OBJECTIVE

The aim of the study was to apply a CTA-based approach to identify the cognitive aspects of performing ESD, and to generate qualitative insights for training.

MATERIALS AND METHODS

Semi-structured interviews were designed based on the CTA framework to elicit knowledge of ESD practitioners relating to the various tasks involved in the procedure. Three observations were conducted of expert ESD trainers either while they performed actual ESD procedures or at a training workshop. Interviews were either conducted over the phone or in person. Interview participants included four experts and four novices. The observation notes and interviews were analyzed for emergent qualitative themes and relationships.

RESULTS

The qualitative analysis yielded thematic insights related to four main cognition-related categories: learning goals/principles, challenges/concerns, strategies, and decision-making. The specific insights under each of these categories were systematically mapped to the various tasks inherent to the ESD procedure.

CONCLUSIONS

The CTA approach was applied to identify cognitive themes related to ESD procedural tasks. Insights developed based on the qualitative analysis of interviews and observations of ESD practitioners can be used to inform the design of ESD training systems, such as virtual reality-based simulators.

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.

The efficacy of endoscopic submucosal dissection for colorectal tumors extending to the dentate line

PURPOSE

Although endoscopic submucosal dissection (ESD) is becoming the mainstay of the treatment strategies, rather than surgical treatment, for colorectal tumors extending to the dentate line, ESD is technically more difficult. This study was aimed at assessing the usefulness of ESD for the treatment of colorectal tumors extending to the dentate line.

METHODS

This study included 531 patients with colorectal tumors who underwent colorectal ESD between 2008 and 2015. They were divided into three groups: rectal tumors extending to the dentate line (anorectal group), those not extending to the dentate line (proximal rectal group), and colonic tumors (colonic group), and a retrospective comparative analysis was carried out.

RESULTS

Of the total patients, 18 (3.4%) had lesions extending to the dentate line area. The procedure times were 103.4 ± 84.0, 80.4 ± 64.3, and 71.8 ± 52.3 min, respectively (P = 0.0318). All the patients in the anorectal group were operated by operators who had performed at least 20 colorectal ESDs (P < 0.0001). No significant difference among the three groups was found in the en bloc resection rate, complete resection rate, or curative resection rate. Although no significant difference in the incidence of perforation was observed among the three groups, intraoperative bleeding was observed in 61% of the patients in the anorectal group (P < 0.0001).

CONCLUSIONS

ESD is an effective treatment strategy for colorectal tumors extending to the dentate line. However, it seems that anorectal ESD, which is technically more difficult than colorectal ESD, should be performed by operators with ample experience in performing ESD.

Feasibility of colorectal endoscopic submucosal dissection (ESD) carried out by endoscopists with no or little experience in gastric ESD

BACKGROUND AND AIM

Colorectal endoscopic submucosal dissection (ESD) is recommended to be carried out only by endoscopists with sufficient experience in gastric ESD. However, early gastric carcinoma is less common in Western countries than in Japan, and endoscopic maneuverability differs between the stomach and colorectum. We assessed the feasibility of colorectal ESD carried out by endoscopists with no or little experience in gastric ESD.

METHODS

We analyzed en bloc resection, R0 resection and perforation rates in 180 consecutive colorectal ESD carried out by three endoscopists who had no or <5 cases of experience in gastric ESD. We also identified factors associated with R0 resection failure.

RESULTS

Overall en bloc and R0 resection rates were 93.3% (168/180) and 82.2% (148/180), respectively. All 11 cases with perforation were treated endoscopically. Dividing 180 cases into three learning phases (early, middle, or late phases), the en bloc and R0 resection rates increased from 88.3% and 75.0% in the early phase to 98.3% and 88.3% in the late phase, respectively. Perforation rate also improved from 10.0% to 3.3%. Factors associated with R0 resection failure were location at junctions (odds ratio: 6.8, 95% CI: 1.9-27.5), preoperative factors reflecting fibrosis (5.8, 1.9-19.0), and late phase (0.2, 0.1-0.7).

CONCLUSION

Endoscopists without experience in gastric ESD carried out colorectal ESD safely. In the early and middle phases (≤40 cases), they should treat mainly rectal lesions but may also resect lesions in the colon avoiding flexures. Lesions located at junctions and those with preoperative factors reflecting fibrosis should be resected after completing 40 procedures.

Simulator training in gastrointestinal endoscopy - From basic training to advanced endoscopic procedures

Simulator-based gastrointestinal endoscopy training has gained acceptance over the last decades and has been extensively studied. Several types of simulators have been validated and it has been demonstrated that the use of simulators in the early training setting accelerates the learning curve in acquiring basic skills. Current GI endoscopy simulators lack the degree of realism that would be necessary to provide training to achieve full competency or to be applicable in certification. Virtual Reality and mechanical simulators are commonly used in basic flexible endoscopy training, whereas ex vivo and in vivo models are used in training the most advanced endoscopic procedures. Validated models for the training of more routine therapeutic interventions like polypectomy, EMR, stenting and haemostasis are lacking or scarce and developments in these areas should be encouraged.

Endoscopic ultrasound-guided inoculation of transmissible venereal tumor in the colon: A large animal model for colon neoplasia

Background:

To develop and evaluate the feasibility of emerging interventions, animal models with accurate anatomical environment are required.

Objectives:

We aimed to establish a clinically relevant colorectal tumor model with canine transmissible venereal tumor (CTVT) utilizing endoscopic ultrasound (EUS) imaging guidance.

Design:

Survival study using a canine model.

Setting:

Endoscopic animal research laboratory at a tertiary cancer center.

Materials and Methods:

This study involved five canines.

Interventions:

A colorectal tumor model was established and evaluated in five canines under cyclosporine immune suppression. Under endoscopic imaging guidance, saline was injected into the submucosal layer forming a bleb. Subsequently, CTVT was inoculated into the bleb under EUS guidance. Endoscopy was the primary method of assessing tumor growth. Tumors developed in 60-130 days. Upon detection of lesions >1 cm, the animals were euthanized and the tumors were harvested for histopathological characterization.

Main outcome measurements:

Success rate of tumor growth. The presence or absence of vasculature inside tumors.

Results:

Colorectal tumor successfully developed in three out of the five animals (60%). Among the ones with tumor growth, average inoculated CTVT volume, incubation time, and tumor size was 1.8 cc, 65.7 days, and 2.0 cm, respectively. The two animals without tumor growth were observed for >100 days. In all the tumors, vascular structure was characterized with CD31 imunohistochemical stain.

Limitations:

Small number of animals.

Conclusion:

We succeeded in creating a new colorectal tumor canine model with CTVT utilizing EUS.

Usefulness of training using animal models for colorectal endoscopic submucosal dissection: is experience performing gastric ESD really needed?

BACKGROUND AND STUDY AIMS

Despite the clinical advantages of colorectal endoscopic submucosal dissection (ESD), an effective training system, especially for Western endoscopists, has been challenging to establish. Herein, we propose a novel training program using ex vivo animal models and evaluate the learning curve of colorectal ESD trainees without gastric ESD experience.

PATIENTS AND METHODS

A total of 80 colorectal lesions were prospectively collected and removed by two novice operators. Before human ESD procedures, they received ESD training using an ex vivo porcine "proximal colon" model, which simulates a lumen with many folds and flexions. To assess the validity of our training system, the self-completion and en bloc R0 resection rates, the operation time, and prevalence of complications were compared between the first and latter period. Moreover the factors associated with prolonged operation time were evaluated.

RESULTS

The overall rates of self-completion and en bloc R0 resection were 98 % (78/80) and 100 % (80/80), respectively. The operation time during the first period was significantly longer than that during the latter period (86 ± 50 minutes vs. 60 ± 36 minutes, P = 0.01). Regarding complications, only two cases of perforations and delayed hemorrhage were observed during the first period; however, all of the complications were successfully managed endoscopically. The presence of fibrosis was identified as a significant independent predictor of a prolonged operation time during the first period (coefficient, 5.90; 95 %CI, 2.36 - 9.44, P = 0.002).

CONCLUSIONS

Our trainees achieved high rates of self-completion and R0 resection without severe complications even during the first 20 cases, suggesting that our training programs using ex vivo animal models are useful for trainees without gastric ESD experience.

STUDY REGISTRATION

UMIN000013566.

In vivo porcine training model for laparoscopic Roux-en-Y choledochojejunostomy

Purpose

The purpose of this study was to develop a porcine training model for laparoscopic choledochojejunostomy (CJ) that can act as a bridge between simulation models and actual surgery for novice surgeons. The feasibility of this model was evaluated.

Methods

Laparoscopic CJ using intracorporeal sutures was performed on ten animals by a surgical fellow with no experience in human laparoscopic CJ. A single layer of running sutures was placed in the posterior and anterior layers. Jejunojejunostomy was performed using a linear stapler, and the jejunal opening was closed using absorbable unidirectional sutures (V-Loc 180).

Results

The average operation time was 131.3 ± 36.4 minutes, and the CJ time was 57.5 ± 18.4 minutes. Both the operation time and CJ time showed a steady decrease with an increasing number of cases. The average diameter of the CBD was 6.4 ± 0.8 mm. Of a total of ten animals, eight were sacrificed after the procedure. In two animals, a survival model was evaluated. Both pigs recovered completely and survived for two weeks, after which both animals were sacrificed. None of the animals exhibited any signs of bile leakage or anastomosis site stricture.

Conclusion

The porcine training model introduced in this paper is an adequate model for practicing laparoscopic CJ. Human tissue simulation is excellent.

Impact of formal training in endoscopic submucosal dissection for early gastrointestinal cancer: A systematic review and a meta-analysis

AIM: To summarize the clinical impact of a formal training for the effectiveness and safety of endoscopic submucosal dissection for gastrointestinal cancer.

METHODS: We searched databases including PubMed, EMBASE and the Cochrane Library and Science citation Index updated to August 2014 to include eligible articles. In the Meta-analysis, the main outcome measurements were en bloc resection rate, local recurrence rate (R0) and the incidence of procedure-related complications (perforation, bleeding).

RESULTS: En bloc resection was high for both, dissecting stomach tumors with an overall percentage of 93.2% (95%CI: 90.5-95.8) and dissecting colorectal tumors with an overall percentage of 89.4% (95%CI: 85.1-93.7). Although the number of studies reporting R0 resection (the dissected specimen was revealed free of tumor in both vertical and lateral margins) was small, the overall estimates for R0 resection were 81.4% (95%CI: 72-90.8) for stomach and 85.9% (95%CI: 77.5-95.5) for colorectal tumors, respectively. The analysis showed that the percentage of immediate perforation and bleeding were very low; 4.96 (95%CI: 3.6-6.3) and 1.4% (95%CI: 0.8-1.9) for colorectal tumors and 3.1% (95%CI: 2.0-4.1) and 4.8% (95%CI: 2.8-6.7) for stomach tumors, respectively.

CONCLUSION: In order to obtain the same rate of success of the analyzed studies it is a necessity to create training centers in the western countries during the “several years” of gastroenterology residence first only to teach EGC diagnose and second only to train endoscopic submucosal dissection.

Endoscopic submucosal dissection in the colorectum: Feasibility in the Canadian setting

Endoscopic submucosal dissection is a minimally invasive endoscopic technique for the removal of gastrointestinal tumours that is increasingly being used for colonic neoplasms to spare resection of colon in selected patients. Colonic endoscopic submucosal dissection is technically challenging and was initially pioneered in Japan but increasingly used in selected western centres. Its use in Canada is currently limited, and the authors review the challenges and opportunities, in addition to the unique training infrastructure required to practice the procedure under supervision. Specific tools are required to perform endoscopic submucosal dissection and meticulous attention to detail is essential. The authors provide a combined Japanese and Canadian perspective to this technique, and discuss training and performance of endoscopic submucosal dissection as well as potential indications.

Training methods and models for colonoscopic insertion, endoscopic mucosal resection, and endoscopic submucosal dissection

Colonoscopic examination is considered an effective examination for the detection of colorectal cancers. Additionally, early colorectal cancers can be resected using endoscopic techniques such as endoscopic mucosal resection and endoscopic submucosal dissection. However, those examinations and treatments need special techniques. Various training methods are practiced to acquire such endoscopic techniques throughout the world. In clinical cases, magnetic positioning devices help endoscopic insertion by less experienced endoscopists. There is a physical model made by polyvinyl chloride and a virtual simulator for training of colonoscopic insertion. Various techniques including a method to apply pressure to the abdomen and consideration for patient's pain can be trained using these models. In view of extensive training of endoscopic mucosal resection and endoscopic submucosal dissection, animal models are useful and actually used. Live animal models of minipig, which entails blood flow, are ideal and used frequently, but are cumbersome to prepare. On the other hand, ex vivo animal models using intestine of porcine and bovine are convenient for preparation and less expensive. Unique ex vivo animal models with blood flow have been developed recently and techniques for hemostasis can be practiced. With respect to a method of training for colorectal endoscopic submucosal dissection, a stepwise system has been adopted throughout the world. Thus, first they observe the expert's technique, then practice training of animal models, and finally, they perform clinical rectal cases. The system is useful for a safe and definite procedure. In this review, we reveal various training methods for colonoscopic examinations and treatments.

Role of observation of live cases done by Japanese experts in the acquisition of ESD skills by a western endoscopist

AIM: To evaluate the role of observation of experts performing endoscopic submucosal dissection (ESD) in the acquisition of ESD skills.

METHODS: This prospective study is documenting the learning curve of one Western endoscopist. The study consisted of three periods. In the first period (pre-observation), the trainee performed ESDs in animal models in his home institution in the United States. The second period (observation) consisted of visit to Japan and observation of live ESD cases done by experts. The observation of cases occurred over a 5-wk period. During the third period (post-observation), the trainee performed ESD in animal models in a similar fashion as in the first period. Three animal models were used: live 40-50 kg Yorkshire pig, explanted pig stomach model, and explanted pig rectum model. The outcomes from the ESDs done in the animal models before and after observation of live human cases (main study intervention) were compared. Statistical analysis of the data included: Fisher’s exact test to compare distributions of a categorical variable, Wilcoxon rank sum test to compare distributions of a continuous variable between the two groups (pre-observation and post-observation), and Kruskal-Wallis test to evaluate the impact of lesion location and type of model (ex-vivo vs live pig) on lesion removal time.

RESULTS: The trainee performed 38 ESDs in animal model (29 pre-observation/9 post-observation). The removal times post-observation were significantly shorter than those pre-observation (32.7 ± 15.0 min vs 63.5 ± 9.8 min, P < 0.001). To minimize the impact of improving physician skill, the 9 lesions post-observation were compared to the last 9 lesions pre-observation and the removal times remained significantly shorter (32.7 ± 15.0 min vs 61.0 ± 7.4 min, P = 0.0011). Regression analysis showed that ESD observation significantly reduced removal time when controlling for the sequence of lesion removal (P = 0.025). Furthermore, it was also noted a trend towards decrease in failure to remove lesions and decrease in complications after the period of observation. This study did not find a significant difference in the time needed to remove lesions in different animal models. This finding could have important implications in designing training programs due to the substantial difference in cost between live animal and explanted organ models. The main limitation of this study is that it reflects the experience of a single endoscopist.

CONCLUSION: Observation of experts performing ESD over short period of time can significantly contribute to the acquisition of ESD skills.

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)

BACKGROUND

A prototype endoscope was designed to improve visualization and dissection of tissue with the use of 2 working channels with different deflections.

OBJECTIVE

To evaluate the efficacy and operability of a prototype endoscope in comparison with a conventional double-channel endoscope for rectal endoscopic submucosal dissection (ESD).

DESIGN

Randomized, prospective, controlled, ex vivo study.

SETTING

Academic medical center.

METHODS

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.

MAIN OUTCOME MEASUREMENTS

An independent observer recorded procedure time, specimen size, en bloc resection, and perforation rate.

RESULTS

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.

LIMITATIONS

Ex vivo study.

CONCLUSION

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.

Training in endoscopic submucosal dissection

Endoscopic submucosal dissection (ESD) represents an important advancement in the therapy of early neoplastic gastrointestinal lesions by providing higher en-bloc curative resection rate with lower recurrence compared to endoscopic mucosal resection (EMR) and by sparing the involved organ and protecting patient’s quality of life. Despite these advantages ESD is associated with long procedure times and a higher rate of complications, making ESD a challenging procedure which requires advanced endoscopic skills. Thus, there has been a recognized need for structured training system for ESD to enhance trainee experience and, to reduce the risks of complications and inadequate treatment. ESD has a very flat learning curve. However, we do not have uniformly accepted benchmarks for competency. Nevertheless, it appears that, in Japan, more than 30 supervised gastric ESD procedures are required to achieve technical proficiency and minimize complications. A number of training algorithms have been proposed in Japan with the aim to standardize ESD training. These algorithms cannot be directly applied in the West due to substantial differences including the availability of highly qualified mentors, the type of pathology seen, choice of devices, and trainee’s background. We propose a training algorithm for Western physicians which integrates both hands-on training courses, animal model work as well as visits to expert centers. No specific preceptor training programs have been yet developed but there is a consensus that these programs are important for permeation of ESD worldwide.

Training in endoscopic submucosal dissection

Endoscopic submucosal dissection (ESD) represents an important advancement in the therapy of early neoplastic gastrointestinal lesions by providing higher en-bloc curative resection rate with lower recurrence compared to endoscopic mucosal resection (EMR) and by sparing the involved organ and protecting patient's quality of life. Despite these advantages ESD is associated with long procedure times and a higher rate of complications, making ESD a challenging procedure which requires advanced endoscopic skills. Thus, there has been a recognized need for structured training system for ESD to enhance trainee experience and, to reduce the risks of complications and inadequate treatment. ESD has a very flat learning curve. However, we do not have uniformly accepted benchmarks for competency. Nevertheless, it appears that, in Japan, more than 30 supervised gastric ESD procedures are required to achieve technical proficiency and minimize complications. A number of training algorithms have been proposed in Japan with the aim to standardize ESD training. These algorithms cannot be directly applied in the West due to substantial differences including the availability of highly qualified mentors, the type of pathology seen, choice of devices, and trainee's background. We propose a training algorithm for Western physicians which integrates both hands-on training courses, animal model work as well as visits to expert centers. No specific preceptor training programs have been yet developed but there is a consensus that these programs are important for permeation of ESD worldwide.

Prevention and management of complications of and training for colorectal endoscopic submucosal dissection

Endoscopic submucosal dissection (ESD) is reported to be an efficient treatment with a high rate of en bloc resection for large colorectal tumors in Japan and some other Western and Asian countries. ESD is considered less invasive than laparoscopic colectomy. However, ESD carries a higher risk of perforation than endoscopic mucosal resection (EMR). Various devices and training methods for colorectal ESD have been developed to solve the difficulties. In this review, we describe the complications of colorectal ESD and prevention of those complications. On the other hand, colorectal ESD is difficult for less-experienced endoscopists. The unique step-by-step ESD training system is performed in Japan. Additionally, appropriate training, including animal model training, for colorectal ESD should be acquired before working on clinical cases.

Endoscopic knot tying: In vitro assessment in a porcine stomach model

AIM: To determine if surgical knotting performed via endoscopy is an effective closure method for natural orifice translumenal endoscopic surgery.

METHODS: The proposed method was tested on an in vitro pig stomach model using standard endoscopy suite materials. A single use laparoscopy trocar (Versaport Plus manufactured by Tyco Healthcare) was fixed onto a plastic rectangular box in a horizontal position. A fresh pig stomach was tightly attached via its esophageal end to the trocar opening on the inner side of the box. The stomach cavity was closed at the duodenal end with Kocher forceps. A standard upper gastrointestinal endoscope fitted at its tip with a transparent plastic cap was introduced into the stomach through the outer trocar opening, so that the passage of the surgical trocar would mimic the passage of an esophagus. The stomach was subsequently inflated, followed by irrigation and washing. A neutral electrode of an electrocautery unit was placed inside the plastic box, underneath the pig stomach. The stomach’s outer surface was kept moist using normal saline in order to maintain the natural elasticity and to ensure good contact with the electrode.

RESULTS: The submucosal space on the anterior face of the stomach was accessed using the technique of endoscopic submucosal dissection. First, a site on the anterior face of the stomach was chosen, near the angle. Then, saline was injected into the submucosa with a standard endoscopic needle, so as to create a 20 mm diameter elevation. A linear 15 mm vertical incision was created at its center using a Dual Knife (KD650U manufactured by Olympus). This incision was used to access the submucosal space, and about 10 mm was dissected on both sides of the incision. The endoscope was then pushed through to the outside of the stomach after dilating a small puncture made by the Dual Knife in the muscularis propria, which simulated the peritoneoscopy procedure. Then, a 0.025” guidewire (Jagwire/450 cm manufactured by Boston Scientific) was inserted into the puncture, followed by a dilating balloon (Quantum TT manufactured by Cook Medical) that was used to enlarge the aperture orifice. After withdrawing the scope back into the stomach, the procedure continued with guidewires being passed from the submucosal space into the gastric lumen through small orifices on the left and right sides of the mucosal opening. These orifices were made with the Dual Knife, and the guidewires were inserted via a guiding catheter (HGC-6 manufactured by Cook Medical). As the guidewires were pulled outside of the stomach, they were replaced with a single surgical suture that had been initially attached to their tip and was now untied. Finally, one loop of this surgical suture was formed on the exterior. One loop end was fixed while the opposite suture end was pulled by biopsy forceps through the endoscope channel as the scope was inserted into the stomach. The loop was advanced until it approached and fixed the two mucosal incision margins. Three alternating loops were made in this manner to create a genuine tight surgical knot.

CONCLUSION: Endoscopic knotting of the gastric wall is feasible, but an in vitro survival study is necessary to validate clinical significance.

Possibility of ex vivo animal training model for colorectal endoscopic submucosal dissection

PURPOSE

Colorectal endoscopic submucosal dissection (ESD) has not been standardized due to technical difficulties and requires extensive training for reliability. Ex vivo animal model is convenient, but has no blood flow. The objective of this study is to evaluate the characteristics of various ex vivo animal models including a blood flow model for colorectal ESD training and the usefulness of practicing endoscopic hemostasis and closure using an animal model.

METHODS

Harvested porcine cecum, rectum, and stomach and bovine cecum and rectum were analyzed regarding ease of mucosal injection, degree of submucosal elevation, and status of the proper muscle layer. Ex vivo animal model with blood flow was made using the bovine cecum. The vessel around the cecum was detached, and red ink was injected. Endoscopic hemostasis for perioperative hemorrhage and endoscopic closure for perforation were performed in this model.

RESULTS

Mucosal injection was easily performed in the bovine cecum and rectum. Submucosal elevation was low in the bovine cecum, while the proper muscle layer was not tight in the porcine rectum and bovine cecum. Endoscopic hemostasis were accomplished in six (60 %) out of ten procedures of the ex vivo blood flow model. In two non-experts, the completion rates of endoscopic closure were 40 and 60 % in the first five procedures. These rates became 100 % in the last five procedures.

CONCLUSIONS

We have evaluated the characteristics of various ex vivo animal models and shown the possibility of training for endoscopic hemostasis and endoscopic closure in the ex vivo animal model.

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

BACKGROUND

Endoscopic submucosal dissection (ESD) has revolutionized the resection of GI superficial neoplasms, but adoption in Western countries is significantly delayed.

OBJECTIVE

To evaluate a stepwise colorectal endoscopic submucosal dissection (ESD) learning and operative training protocol.

DESIGN

Prospective study in the Western setting.

SETTING

This study took place in a nonacademic hospital with one endoscopist expert in therapeutic endoscopy but novice in ESD.

PATIENTS

Indications for ESD were superficial neoplasms 20 mm and larger without ulcerations or fibrosis.

INTERVENTION

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.

MAIN OUTCOME MEASUREMENTS

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.

RESULTS

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.

LIMITATIONS

Single-center design.

CONCLUSIONS

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.

ESD Hands-on Course Using Ex Vivo and In Vivo Models in South Korea

Endoscopic submucosal dissection (ESD) is an established treatment for gastric neoplasias especially in regions with a high volume of gastric cancer. Although ESD has many advantages over endoscopic mucosal resection, ESD is technically more difficult and can result in severe complications. Therefore establishment of an effective training system is required to help endoscopists climb the ESD learning curve. Although a standard training system for ESD remains to be established, some centers are incorporating ex vivo and/or in vivo animal models to provide a safe and effective means of ESD training. However, it is unknown if these animal models are more effective than other programs. Moreover the efficacy of the animal model may vary according to socio-economic status and the volume of gastric cancer. In this article we introduce the basic and advanced ESD training model using the ex vivo and in vivo animal model from South Korea and review the associated literature from other regions.

Ex vivo and in vivo models for endoscopic submucosal dissection training

Endoscopic submucosal dissection is a technically challenging but highly effective technique for the treatment of well selected early neoplasms in the digestive tract. Although it is frequently performed in East Asian countries, the Western world has not adopted this technique yet, probably due in part to the difficulty to learn it. Ex vivo and in vivo animal models are invaluable tools to overcome at least the beginning of the learning curve, although the initial step is the acquisition of basic knowledge about early diagnosis of neoplasias, and observing real procedures in expert centers. The practical issues, advantages, and disadvantages of the ex vivo and in vivo models are discussed.

The learning curve for endoscopic submucosal dissection in an established experimental setting

INTRODUCTION

Endoscopic submucosal dissection (ESD) has become a standard therapy for early gastric neoplasia, particularly in Asian countries. From a safety and efficacy standpoint, simulation training may empower the endoscopist to be able to learn the basic tenets of ESD in a safe, controlled and supervised setting before attempting first in humans.

METHODS AND PROCEDURES

This study was designed as a prospective ex vivo study. Ex vivo porcine organs were utilized in the EASIE-R endoscopic simulator. A total of 150 artificial lesions, each 2 × 2 cm in size, were created in fresh ex vivo porcine stomachs at six different anatomical sites (fundus anterior and posterior, body anterior and posterior, antrum anterior and posterior). Three examiners (2 beginners, 1 expert) participated in this study. All parameters (procedure time, specimen size, en-bloc resection status, perforation) were recorded by an independent observer for each procedure.

RESULTS

All 150 lesions were successfully resected using the ESD technique by the three endoscopists. After 30 ESD cases, the two novices performed ESD with a 100% en-bloc resection rate and without perforation. For the procedures performed by the novices, the total procedure time and perforation rate in the last 30 cases were significantly lower than during the first 30 cases (p < 0.05).

CONCLUSIONS

Our study suggests that performing 30 ESD resections in an ex vivo simulator leads to a significant improvement in safety and efficiency of performing the ESD technique.

Current opinions for endoscopic submucosal dissection for colorectal tumors from our experiences: indications, technical aspects and complications

Endoscopic submucosal dissection (ESD) was first applied in the resection of large colorectal tumors 10 years ago. Frequent complications and technical difficulties were serious problems at first, but were gradually improved with experience. Here, we describe the indications, technical aspects and management of complications of ESD for colorectal tumors. In 2009, we introduce the use of small tip insulation-tipped diathermic (IT) knife. Features separating it from the IT knife and IT Knife2 are a smaller ceramic tip and small round disk at the root of the tip. During submucosal dissection, the small tip IT knife could dissect large pieces of tissue intact. This allows us to shorten the procedure time, particularly the submucosal dissection component. A total of 146 ESD for 140 patients were performed between January 2009 and July 2011. En bloc, and en bloc and R0 resection rates were 92.5% and 83.6%, respectively. Median procedural time was 48.5 min for 40.5 mm specimens. Perforation and delayed bleeding occurred in 2.1% and 1.4%, respectively. We successfully performed ESD for colorectal tumors with a shortened procedure time while preserving quality and safety.

[Endoscopic submucosal dissection: only for expert endoscopists?]

Endoscopic submucosal dissection (ESD) can be applied to early gastrointestinal cancers. This technique was developed to achieve radical curative resection and to reduce unnecessary surgical interventions. ESD was designed in eastern countries and is not widely used in the West. Although ESD represents a major therapeutic advance in endoscopy and is performed with curative intent, the complication rate (hemorrhage, perforation) is higher than reported in other techniques, requiring from endoscopists the acquirement of technical skill and experience through a structured and progressive training program to reduce the morbidity associated with this technique and increase its potential benefits. Although there is substantial published evidence on the applications and results of ESD, there are few publications on training in this technique and a standardized training program is lacking. The current article aims to describe the various proposals for training, as well as the basic principles of the technique, its indications, and the results obtained, since theoretical knowledge that would guide endoscopists during the clinical application of ESD is advisable before training begins. Training in an endoscopic technique has a little value without knowledge of the technique's aims, the situations in which it should be applied, and the results that can be expected.

Routine and advanced polypectomy techniques

The performance of colon polypectomy has proven to be one of the most impactful services provided by today's endoscopist. Advancements in instrumentation and endoscopic techniques have been studied intensely by endoscopists over the past decade in order to expand their extent of resection capabilities to large and complex polyps. Much of the research in the past year has focused on the safety and efficacy of performing endoscopic mucosal resection (EMR), endoscopic submucosal dissection (ESD), and combined laparascopic-endoscopic resections (CLER). Experts have published case-series, multicenter studies, and even nationwide results on the use of these methods for complex polypectomy. Because of the novelty and increased risk of these procedures, recent research has also focused on the prevention, identification and management of complications related to polypectomy, particularly bleeding and perforation. This manuscript will review the recent literature addressing basic and advanced colon polypectomy techniques.

Ex vivo pig training model for esophageal endoscopic submucosal dissection (ESD) for endoscopists with experience in gastric ESD

BACKGROUND

Esophageal endoscopic submucosal dissection (ESD) has developed in recent years because of its high rate of en bloc resection. However, for many endoscopists, technical difficulty and risks of complications are great barriers to performing esophageal ESD. In this study, we developed an original training model for esophageal ESD using isolated pig esophagus and assessed this ex vivo model in endoscopists with experience in gastric ESD.

METHODS

Three endoscopists without experience in esophageal ESD but with some experience in gastric ESD performed esophageal ESD of artificial lesions in 10 consecutive sessions using this ex vivo model. The en bloc resection rate, operation time, number of muscularis propria layer injuries, and presence of perforation were recorded. We evaluated the effectiveness of this training in the three endoscopists by comparing results from the first five sessions (former period) with those from the last five sessions (latter period).

RESULTS

All three endoscopists achieved en bloc resections in all trials. In the former period, injury to the muscularis propria layer for each of the three endoscopists occurred a mean of 2.2 (1-3), 0.6 (0-1), and 3.2 (1-6) times, respectively. Perforation occurred in one session performed by one endoscopist. In the latter period, the mean number of muscularis propria layer injuries for each of the three endoscopists decreased to 0.2 (0-1), 0.2 (0-1), and 0.8 (0-2), respectively. The time of operation shortened from 35.0 (25-40), 36.4 (30-50), and 29.8 (23-43) min to 23.0 (16-31), 25.6 (23-28), and 29.2 (21-37) min, respectively.

CONCLUSIONS

This original ex vivo training model was helpful to endoscopists with experience in gastric ESD in acquiring the basic skills for performing esophageal ESD.

Endoscopic submucosal dissection for colonic lesions: why and how should we do it?

Endoscopic submucosal dissection (ESD) is a safe and effective alternative to surgery for large non-polypoid colonic lesions and early colorectal carcinoma. In this article, we discuss the development, efficacy and safety of ESD. As the incidence of colorectal cancer is rapidly increasing in Asia, we advocate standardization of ESD program, including patient selection, hardware prerequisites, and training of operators.

Endoscopic colorectal imaging and therapy

PURPOSE OF REVIEW

Colorectal cancer screening and prevention is a pivotal element in every gastroenterologist practice. Recent advances in imaging technology and treatment opened the field for endoscopic management of large flat colorectal polyps and early cancer.

RECENT FINDINGS

High-definition white light colonoscopy allowed for better characterization of colon polyps, particularly flat lesions. Chromoendoscopy facilitated the identification of colon polyps as well as better endoscopic polyp characterization, with strong correlation with final pathological diagnosis, opening the field of 'virtual' biopsy. One particular technology, confocal endomicroscopy can magnify an image approximately 1000 times resembling optical microscopy with very good correlation with histology. Endoscopic mucosal resection has gained great acceptance to manage flat colorectal polyps with the two major complications being bleeding and perforation, both now under 5% in experienced hands. Endoscopic submucosal resection was developed to increase en-bloc resection (less residual disease) of a flat colorectal lesion but one has to accept a higher perforation rate around 10%.

SUMMARY

Current technology allows for better polyp identification and characterization, which can be managed endoscopically.