Improved model for teaching interventional EUS

Background: A swine model was previously developed for teaching endoscopic ultrasound (EUS). The purpose of this study was to improve this model and develop a method for creating focal lesions for EUS imaging and intervention. Methods: Experiments were performed in farm pigs (Sus scrofa) under general anesthesia. Under real-time EUS guidance attempts were made to create a submucosal lesion and a focal mediastinal lesion, to perform EUS-guided fine-needle aspiration of the pancreas, and to confirm the site of injection during 'sham' EUS-guided celiac block. Results: A hypoechoic, submucosal mass was created in the stomach, which was then imaged by EUS and punctured trans-gastrically. Injection of saline solution in the mediastinum created a pseudo-mediastinal lymph node. A needle was then advanced trans-esophageally into the mediastinum to mimic EUS-guided fine-needle aspiration of a mediastinal lymph node. Abdominal exploration of the pigs after euthanasia confirmed injection of the sham celiac block around the celiac ganglion. Conclusion: The swine model is not only useful for teaching normal EUS anatomy, but it may be a useful model for teaching EUS-guided intervention.