Magnetic pancreaticobiliary stents and retrieval system: Obviating the need for repeat endoscopy (with video)

Division of Gastroenterology, Brigham & Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Gastrointestinal endoscopy (Impact Factor: 5.37). 01/2012; 75(4):888-892.e1. DOI: 10.1016/j.gie.2011.09.051
Source: PubMed


Plastic stents are routinely placed in the pancreaticobiliary system to facilitate drainage. A second endoscopy is often required for stent removal. We have developed magnetic pancreaticobiliary stents that can be removed by using an external hand-held magnet, thereby obviating the need for a second endoscopy.
To develop and test magnetic pancreaticobiliary stents and retrieval system in ex-vivo and in-vivo porcine models.
Animal laboratory.
Benchtop and animal study.
5 pigs.
Design: Computer simulations determined both the optimal design of cylindrical magnets attached to the distal aspect of existing plastic stents and the optimal design of the external hand-held magnet. Benchtop ex-vivo experiments measured magnetic force to validate the design. In-vivo analysis: In 5 Yorkshire pigs, magnetic stents were deployed into the common bile duct by using a conventional duodenoscope. An external hand-held magnet was applied for stent removal. Stent insertion and removal times were recorded.
Technical feasibility.
Magnetic stents of varying lengths and calibers were successfully created. In ex-vivo testing, the capture distance was 10.0 cm. During in-vivo testing, the magnetic stents were inserted and removed easily. The mean insertion and removal times were 3.2 minutes and 33 seconds, respectively.
Animal study, small numbers.
Magnetic pancreaticobiliary stents and associated retrieval system were successfully designed and tested in the acute porcine model. An external, noninvasive means of stent removal potentially obviates the need for a second endoscopy, which could represent a major gain both for patients and in health care savings.

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    • "This work has been demonstrated in vitro via a plastic phantom and in vivo in the porcine model [10]. Other work includes that of the Development Endoscopy Laboratory at Harvard who have demonstrated removal of pancreatic and biliary stents in pigs by means of magnetic coupling [11], [12]. Kume et al. demonstrated porcine laparoscopic cholecystectomy [13] and colonic resection [14] with the aid of magnetic retraction. "
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