Clinical endoscopic intervention of the pancreaticobiliary tree
[endoscopic retrograde cholangiopancreatography (ERCP)] often concludes
with the insertion of a temporary plastic stent to reduce the risk of
post-ERCP complications by promoting continued flow of bile and
pancreatic fluids. This stent is later removed once the patient has
fully recovered, but today this necessitates a second endoscopic
intervention. The final goal of this work is to obviate the second
intervention. This is to be achieved by adding a magnetic ring to the
stent such that the stent is removed using a hand-held magnet, held in a
suitable position ex vivo . This paper details the design, optimization, and both ex vivo and in vivo
testing of the magnetized stent and hand-held magnet, which has been
accomplished to date. The optimized design for the hand-held magnet and
the modified stent with a magnetic attachment performs in line with
simulated expectations, and successful retrieval is achieved in the
porcine ex vivo setting at 9-10 cm separation. This is comparable
to the mean target capture distance of 10 cm between the entry point to
the biliary system and the closest cutaneous surface, determined from
random review of clinical fluoroscopies in ten human patients.
Subsequently, the system was successfully tested in vivo in the
acute porcine model, where retrieval at an estimated separation of 5-6
cm was captured on endoscopic video. These initial results indicate that
the system may represent a promising approach for the elimination of a
second endoscopic procedures following placement of pancreatic and
biliary stents.