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

Ryou, Marvin; Cantillon-Murphy, Padraig; Shaikh, Sohail N.; Azagury, Dan; Ryan, Michele B.; Lang, Jeffrey H.; Thompson, Christopher C.

doi:10.1016/j.gie.2011.09.051

« Previous Next »Gastrointestinal Endoscopy
Volume 75, Issue 4 , Pages 888-892.e1, April 2012

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

Marvin Ryou, MD
- Division of Gastroenterology, Brigham & Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
Padraig Cantillon-Murphy, PhD
- Department of Electrical Engineering, University College Cork, Cork, Ireland
Sohail N. Shaikh, MD
- Section of Gastroenterology, University of Arizona College of Medicine, University Medical Center, Tuscon, Arizona, USA
Dan Azagury, MD
- Department of Surgery, Brigham & Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
Michele B. Ryan, MS
- Division of Gastroenterology, Brigham & Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
Jeffrey H. Lang, ScD
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
Christopher C. Thompson, MD, MSc, FACG, FASGE
- Division of Gastroenterology, Brigham & Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
- Reprint requests: Christopher Thompson, MD, Division of Gastroenterology, 75 Francis St, Boston, MA 02115

Received 28 July 2011; accepted 30 September 2011. published online 09 January 2012.

Background

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.

Objective

To develop and test magnetic pancreaticobiliary stents and retrieval system in ex-vivo and in-vivo porcine models.

Setting

Animal laboratory.

Design

Benchtop and animal study.

Animals

5 pigs.

Interventions

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.

Main Outcome Measurements

Technical feasibility.

Results

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.

Limitations

Animal study, small numbers.

Conclusions

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.