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

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. 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. The median time for localization of all SMTs was 40.1 seconds for experts and 38.5 seconds for novices ( = 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 ( = 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 ( = 0.38). There was a higher rate of mucosal injury and muscular perforation in the novice group (8 vs 0;  = 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 ( = 0.38). One mucosal injury was incurred by a novice. The rate of dissection in the stomach and the oesophagus was not statistically different ( = 0.620). All participants voted that the model provides a realistic simulation and recommended it for training. 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.