Antimigration Effects of the Number of Flaps on a Plastic Stent: Three-Dimensionally Printed Pancreatic Phantom and Ex Vivo Studies

Abstract

Stent migration is a significant obstacle to successful stent placement. There has been no investigation of the effect and quantitative interpretation of flaps attached to a plastic stent (PS) on antimigration. The antimigration effects of the number of flaps on a PS in a 3D-printed pancreatic phantom (3DP) and extracted porcine pancreas (EPP) were investigated. Four PS types were used in this study: stent without flaps (type 1), stent with two flaps (type 2), stent with four horizontally made flaps (type 3), and stent with four vertically made flaps (type 4). The stents were measured and compared for antimigration force (AMF) in the 3DP and EPP using a customized measuring method and an integrated measuring device. The mean maximum AMFs (MAMFs) in types 2, 3, and 4 were significantly higher than that in type 1 (all p < 0.001). Moreover, the mean MAMFs in types 3 and 4 were significantly higher than that in type 2 (all p < 0.001). When the flaps were removed from the pancreatic duct, the AMF decreased rapidly. As the number of flaps increased, the antimigration effects significantly increased in the 3DP and EPP. However, the direction of the flaps did not affect the MAMF. The position of the flaps attached to the surface of the stent affected the AMF.