An innovative ex-vivo porcine upper gastrointestinal model for submucosal tunnelling endoscopic resection (STER).

Background and study aims: Submucosal tunnelling endoscopic resection (STER) is a novel endoscopic technique to remove submucosal tumour (SMT). We propose a novel, low cost simulator for training of techniques for STER. Patients and methods: The model consisted of an ex-planted porcine oesophagus, stomach and duodenum with marbles embedded surgically in the submucosal plane. Two expert endoscopists with experience in submucosal tunnelling and 5 board-certified endoscopists with no experience in submucosal tunnelling were recruited. Participants were asked to perform a diagnostic endoscopy and 2 STER procedures, 1 in the oesophagus and 1 in the stomach. They also answered a structured questionnaire. Factors including operative time, mucosal and muscular injury rate, injection volume and accuracy of endoscopic closure were assessed. Results: The median time for localization of all SMTs was 40.1 seconds for experts and 38.5 seconds for novices (P = 1.000). For esophageal STER, the length of mucosal incisions and tunnelling distances were comparable between the 2 groups. The median volume injected by the novice group was significantly lower than the experts (15 mL vs 42.5 mL (P = 0.05). The median tunnelling time per length was 25.9 seconds/mm for the experts and 40.8 seconds/mm for the novice group (P = 0.38). There was a higher rate of mucosal injury and muscular perforation in the novice group (8 vs 0; P = 0.05). For gastric STER, the length of mucosal incisions and tunnel distances were comparable between the 2 groups. The median tunnelling time per length for the experts was 23.3 seconds/mm and 34.6 seconds/mm for the novice group (P = 0.38). One mucosal injury was incurred by a novice. The rate of dissection in the stomach and the oesophagus was not statistically different (P = 0.620). All participants voted that the model provides a realistic simulation and recommended it for training. Conclusions: STER is an advanced endoscopic technique where its indication is currently explored. Experienced and novice STER endoscopists have expressed the usefulness of this model as a training tool. This low-cost model can be used for future research in STER.