The Tokyo Metropolitan Industrial Technology Research Center has developed the world's first functional "Stent 1" in collaboration with Tokyo Medical University, University of Fukui, and Keio University.It has unprecedented properties that combine the advantages of conventional stents, and it enables palliative therapy using stents for a long period of time, leading to a significant reduction in the burden on cancer patients and medical professionals.
When the bile duct is obstructed due to pancreatic cancer, bile is not discharged and jaundice develops.Since jaundice is accompanied by fever and nausea, a stent (a tubular medical device that expands the tube from the inside) is endoscopically placed in the bile duct to perform palliative therapy to drain bile.Stent materials are mainly plastic and metal, and plastic stents can be removed but clog early.The metal stent has a wide lumen and shows long-term patency, but the cancer invades from the mesh and cannot be removed.For this reason, the development of a stent that "shows long-term patency and can be removed" has been long-awaited.
The research group focused on polyvinyl alcohol (PVA) hydrogel, which expands when it contains water. PVA is safe for living organisms and can produce sturdy hydrogels.This time, we have developed the world's first self-expandable stent for bile duct drainage using this PVA hydrogel.
This stent is delivered endoscopically to the bile duct in a dry state, and after placement in the bile duct, it self-expands due to swelling due to body fluid such as bile, and the lumen expands.The inner diameter after swelling (about 5 mm) exceeds the inner diameter of a commercially available plastic stent (maximum 3.3 mm), and long-term patency is expected.In the experiment, it was confirmed that the prepared bile duct stent prototype could dilate the pig bile duct.
The newly developed stent is a completely new one that combines the advantages of the current stent, and is expected to significantly reduce the burden on patients and medical professionals who require stent placement in the future.
