Gastrointestinal endoscopy currently includes many therapeutic methods that are technically challenging and frequently associated with a significant risk of complications. Several issues such as the limited number of clinical cases and practice in emergency situations, and technical difficulty may limit the opportunity for training, and increased exposure in more relaxed situations would be desirable. Moreover, providing the patient with the best possible standard of care is a must. Animal models are the most easily available simulators. Training in these models has been recommended for several complex techniques, among which hemostasis, endoscopic ultrasound, endoscopic retrograde cholangiopancreatography, and endoscopic submucosal dissection are reviewed here. Ex vivo models are much easier to set up and, from an ethical standpoint, they should be used for the initial step in training whenever possible before moving on to in vivo models. Although simulation with animal models has been the subject of a good number of studies, very few of them have evaluated the impact on clinical outcomes, and clearly more studies are needed. Nevertheless, available evidence does suggest that practicing on animal models has an influence on the learning curve and facilitates the acquisition of skills in the complex endoscopic techniques reviewed.
