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

Endoscopic submucosal dissection training: evaluation of an ex vivo training model with continuous perfusion (ETM-CP) for hands-on teaching and training in China

BACKGROUND

The existing ex vivo models of endoscopic submucosal dissection (ESD) cannot simulate intraoperative hemorrhage well. We aimed to establish an ESD training method by applying an ex vivo training model with continuous perfusion (ETM-CP).

METHODS

Four training sessions were conducted for 25 novices under the guidance of 2 experts. Eventually, 10 novices completed ESD operations on a total of 89 patients after the training. The resection effectiveness, resection speed, complication rate, and novice performance before and after the training were compared. The data regarding the effects of the training and the model were gathered through a questionnaire survey.

RESULTS

In terms of the simulation effect of the model, ETM-CP was evaluated as similar to the live pig in all aspects (P > 0.05). The questionnaire analysis revealed that the ESD theoretical knowledge, skill operation, and self-confidence of novices were improved after the training (P < 0.05). The resection time per unit area had a correlation with the number of training periods (rs = - 0.232). For novice performance, the resection time per unit area was shortened (P < 0.05). There was no difference in patient performance between the novice group and the expert group after the training in terms of en bloc resection, R0 resection, complication rate, endoscopic resection bleeding (ERB) score, muscularis propria injury (MPI) score, and resection time per unit area (P > 0.05).

CONCLUSION

The ETM-CP is effective for ESD training.

Live endoscopy events (LEEs): European Society of Gastrointestinal Endoscopy Position Statement - Update 2021

The European Society of Gastrointestinal Endoscopy (ESGE) is dedicated to improving the quality of gastrointestinal endoscopy, including through educational activities such as live endoscopy events (LEEs). The primary goal of LEEs should be to facilitate the improvement of endoscopic patient care through the acquisition of best endoscopic practice. Patients should not expect additional benefit from being treated during a LEE compared to a routine setting. There is limited available evidence on LEE safety but to date there is no indication that patients are at increased risk from participation. Pre-recorded cases with live facilitation can also be used to fulfill learning outcomes. Establishing an endoscopic curriculum with clear learning outcomes is important to structure attendees' learning, assess course outcomes, and allow appropriate targeting of courses to learner experience. Increasingly, LEEs are streamed online and therefore the necessary measures should be taken to ensure that patients have given appropriate consent and that their anonymity has been safeguarded. ESGE recommends that an endoscopist who is not participating in the live demonstrations is named as patient advocate, and that patient safety should must be prioritized throughout. In all ESGE-organized LEEs the intended learning outcomes, procedural indications and descriptions, attendee feedback, and adverse events should be recorded and submitted in a post-event report to ESGE.

Prevention and Management of Complications and Education in Endoscopic Submucosal Dissection

Endoscopic submucosal dissection (ESD) is considered superior to endoscopic mucosal resection as an endoscopic resection because of its higher en bloc resection rate, but it is more difficult to perform. As ESD techniques have become more common, and the range of treatment by ESD has expanded, the number of possible complications has also increased, and endoscopists need to manage them. In this report, we will review the management of critical complications, such as hemorrhage, perforation, and stenosis, and we will also discuss educational methods for acquiring and improving ESD skills.

Learning colorectal endoscopic submucosal dissection: a prospective learning curve study using a novel ex vivo simulator

BACKGROUND

Endoscopic submucosal dissection (ESD) is increasingly being used in Asia as a minimally invasive therapy to eradicate large laterally spreading superficial tumors in the colon. To date, the learning curve and effectiveness of ex vivo simulators in colonic ESD training remain unclear. The aim of the study is to determine the learning curve of colonic ESD in an ex vivo simulator.

METHODS

We conducted a prospective study of colon ESD in ex vivo porcine colons in a prototype simulator. Three endoscopists with prior experience in gastric ESD but with no experience in colonic ESD each performed 30 ESD resections on standardized lesions in the rectosigmoid and left colon of the porcine simulator. Procedure time, en bloc resection status, and perforation were recorded.

RESULTS

All 90 lesions were resected using the ESD technique. The mean time of procedure was 49.6 min (standard deviation 29.6 min). The aggregate rate of perforation was 14.4% and the aggregate rate of non-en bloc resection was 5.6%. Using a composite quality score integrating complications and procedural time, it was found that there was a significant difference between two local polynomial regression lines when using a cut-point at the 9th procedure (p = 0.04), reflecting the point at which most of the learning curve is traversed.

CONCLUSIONS

In this study, there were significant improvements realized in colonic ESD performance after 9 colon ESD procedures in ex vivo specimens. Although training will depend on endoscopist skill and expertise, we suggest at least 9 ex vivo procedures prior to moving to live animal or proctored training in colonic ESD.

Tips for safety in endoscopic submucosal dissection for colorectal tumors

In Japan, endoscopic submucosal dissection (ESD) becomes one of standard therapies for large colorectal tumors. Recently, the efficacy of ESD has been reported all over the world. However, it is still difficult even for Japanese experts in some situations. Right-sided location, large tumor size, high degree of fibrosis, difficult manipulation is related with the difficulty. However, improvements on ESD devices, suitable strategies, and increase of operators' experiences enable us to solve these problems. In this chapter, we introduce recent topics about various difficult factors of colorectal ESD and the tips such as strategy, devices, injection, and traction method [Pocket-creation method (PCM) etc.].

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.

Colorectal endoscopic submucosal dissection from a Western perspective: Today’s promises and future challenges

Over the last few years, endoscopic submucosal dissection (ESD) has shown to be effective in the management of early colorectal neoplasms, particularly in Asian countries where the technique was born. In the Western world, its implementation has been slow and laborious. In this paper, the indications for ESD, its learning model, the available methods to predict the presence of deep submucosal invasion before the procedure and the published outcomes from Asia and Europe will be reviewed. Since ESD has several limitations in terms of learning achievement in the West, and completion of the procedure for the first cases is difficult in our part of the world, a short review on colorectal assisted ESD has been included. Finally, other endoscopic and surgical treatment modalities that are in competition with colorectal ESD will be summarized.

Colorectal endoscopic submucosal dissection: Recent technical advances for safe and successful procedures

Endoscopic submucosal dissection (ESD) is very useful in en bloc resection of large superficial colorectal tumors but is a technically difficult procedure because the colonic wall is thin and endoscopic maneuverability is poor because of colonic flexure and extensibility. A high risk of perforation has been reported in colorectal ESD. To prevent complications such as perforation and unexpected bleeding, it is crucial to ensure good visualization of the submucosal layer by creating a mucosal flap, which is an exfoliated mucosa for inserting the tip of the endoscope under it. The creation of a mucosal flap is often technically difficult; however, various types of equipment, appropriate strategy, and novel procedures including our clip-flap method, appear to facilitate mucosal flap creation, improving the safety and success rate of ESD. Favorable treatment outcomes with colorectal ESD have already been reported in many advanced institutions, and appropriate understanding of techniques and development of training systems are required for world-wide standardization of colorectal ESD. Here, we describe recent technical advances for safe and successful colorectal ESD.

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.

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.

[Endoscopic submucosal dissection]

Endoscopic submucosal dissection (ESD) was developed in Japan but has now also become permanently established in various centers in Europe. ESD is an endoscopic en bloc mucosal resection technique for the treatment of early cancers with a diameter >1 cm and also superficial precancerous lesions, which could only be removed unsatisfactorily in several fragments or with uncertain lateral safety margins using previous loop excision procedures. Using ESD a lesion is excised after circular marking and generous submucosal injection with a safety margin of approximately 5 mm and subsequently resected at the level of the submucosa with a 1-3 mm short diathermic knife. ESD requires high technical skills in interventional endoscopy and is more time-consuming than snare resection techniques. However, numerous studies have shown a clear superiority for ESD with respect to the R0 resection rate and the local recurrence rate. The present article gives a current review of the use of ESD in the upper and lower gastrointestinal tract and demonstrates perspectives of the procedure.

Prediction and treatment of difficult cases in colorectal endoscopic submucosal dissection

Purpose. The aim of this study was to examine the characteristics of difficult cases and the learning curve in colorectal endoscopic submucosal dissection (ESD). Methods. We studied 518 colorectal tumors treated by ESD. Patients were divided into 2 groups such as the difficult ESD group and non-difficult ESD group in view of procedure time and procedure speed, respectively. The clinical features in each group were analyzed, and we also examined cases with severe fibrosis. Furthermore, we divided all cases into 5 periods according to experience of ESDs and investigated the rates of difficult and perforation cases. Results. In view of both procedure time and procedure speed, there were significant differences about mean tumor size, rates of severe fibrosis and perforation, and en bloc resection rate between the two groups. Severe fibrosis was detected in protruding tumors >40 mm in diameter. With respect to the learning curve, the rate of difficult and perforation cases decreased significantly in the late periods compared to the first period. Conclusions. Large tumor size, high rates of severe fibrosis and perforation, and low rate of en bloc resection are related with difficult ESD cases. The increasing of experiences can decrease the rate of difficult cases and perforation.

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.