A simple and reproducible training model for endoscopic hepatico-gastrostomy

Aims Interventional endoscopic ultrasound sonography (EUS) is playing an increasingly important part in the training of interventional endoscopists. Among bilio-pancreatic applications, EUS-Guided hepatico-gastrostomy (HGS) is one of the most difficult to acquire and there is no standardized model to boost the learning curve for operators. Our aim was to develop a model reproducing the 4 main stages of an HGS procedure: 1) Location with the linear probe of the left liver (ideally segment III with dilated bile ducts); 2) Needle puncture, opacification and placement of a guidewire in the bile ducts; 3) Confection of a path using a cystotome, and 4) Placement of a partially or fully covered metal stent between the stomach and the bile ducts. We present here a simple, reliable and cost-effective model for HGS training.

Methods 

Gastric wall We use a pig stomach whose esophagus is fixed around a PVC tube (to introduce the device) and whose duodenum is sutured to allow insufflation of the gastric pouch (EASIE model widely described and used in therapeutic endoscopy workshops).

Artificial liver Made using 200-bloom edible gelatin mixed with agar-agar at 30°C. The resulting mixture is hyperechoic and quite similar to liver parenchyma. Biliary tract: Shapable cylindrical shells filled with water ice are immersed frozen in gelatin in the desired shape. As the gelatin cools, it hardens but the ice melts, creating a liquid enclave within the gelatin.

Assembly: The porcine gastric pouch is placed in contact with the hardened gelatin block, through which the tubular structure filled with colored water is clearly visible by EUS. The gelatin block is replaced for each new procedure.

Results This model was tested in real-life conditions on 20 students during the Interventional Endoscopy Curriculum in 2023-2024, and then perfected to facilitate assembly: the bile ducts were initially made using plastic tube molds, which take a long time to position, whereas the use of immersed ice cubes reduces manufacturing time. Gelatin can be reused from morning to afternoon by melting it in the microwave and then remolding it with new water ices. Adding agar to gelatin at low temperature makes the mixture hyperechoic, unlike pure gelatin. Compared with published models using complex 3D printing, it is economical and requires little material, while accurately reproducing the realization of a HGS.

Conclusions This model mimics, in a simple and easily reproducible way, the conditions for performing an HGS with the use of guides, cystotomes and stents under ultrasound and fluoroscopic control. It will be validated during the 2024-2025 interventional endoscopy training workshop of the interventional endoscopy curriculum, incorporating progress curves and feedback from students and expert supervisors. This model can be derived by modifying the gelatin target to obtain biliary ramifications, finer bile ducts or even targets for drainage of collections or choledoco-duodenostomy.

Publikationsverlauf

Artikel online veröffentlicht:
27. März 2025