Inanimate figure tracing and ex vivo pig stomach models to teach endoscope control and ESD: Description of models and preliminary results.

Abstract Background ESD is the gold standard treatment for large sessile adenomas yet US adoption rates are low. In ESD, tissue is cut only when the scope tip, with hot knife extended, is moving; this requires different skills than needed for snare polypectomy (scope tip held still). Scope tip control and ESD training methods are needed. A program including an inanimate figure tracing model (FTM; Model1), ex vivo pig stomach model (PSM; Model2) and bovine colon model was devised. This paper concerns preliminary results for models 1 and 2.Methods A straight hollow plastic tube with a window cutout 15cm from its end was used for both models (slotted sponge = “anus”). For the FTM a paper with a line figure is placed in the window. After endoscope insertion and positioning the figure is traced with a catheter "pen"; 8 tracings (4 figure types) and 1 pig ESD were done per session. In the PSM a piece of pig stomach and Bovie pad was placed over the window. After “lifting” the mucosa ESD resection of a "polyp" was done. Time/accuracy were tracked for both models as were bowel wall injuries in the PSM.Results A total of 30 FTM sessions and PSM cases were done (2 trainees). Completion times and accuracy improved over 8 FTM sessions for less experienced trainee A but not for trainee B. A total of 29/30 PSM cases were completed. The number of deep muscle injuries decreased with time, however, case length correlated with tissue quality and not number of cases. Lifting and tissue conductivity problems were noted in poor quality tissue.Conclusions Despite model related issues, both models are feasible and allow trainees to learn scope tip control and ESD; clearly, more study is needed. A smaller diameter tube and use of fresh stomach are advised.