Magnets for therapy in the GI tract

CantillionMurphy_headshotPádraig Cantillon-Murphy, PhD, from the School of Engineering at University College Cork, in Cork, Ireland discusses this article, “Magnets for therapy in the GI tract: a systematic review.”

This systematic review examined the increasing interest in the use of magnets and magnetic materials for therapeutic purposes in the gastrointestinal tract. The review analyzes 47 publications across clinical and pre-clinical experience in 6 distinct applications; (1) compression anastomosis (both bilioenteric and gastroenteric), (2) anchoring, (3) retraction, (4) sphincter augmentation, (5) feeding tube placement and (6) tumor marking. The review was prompted by the considerable uptake in the use of magnets by the clinical community, often without the requisite technical input. By analyzing reported uses of magnets and their success in the therapeutic setting (both clinical and pre-clinical), it is hoped that the review will provide a more scientific basis for the selection and specification of magnetic materials in future studies. In addition, it was felt that there has been a lot of hype surrounding magnets in some quarters, as evidenced by the increased commercial and published activity in the field in recent years. While simple to use and promising for certain applications, the use of magnets needs to be better understood by the clinical community before the magnets become part of everyday mainstream treatments.

Figure 5. The intracorporeal magnetic anchoring and guidance system camera from the MAGS system.(44) The magnet and camera are housed inside a 7.5-cm enclosure that may be laparoscopically deployed and anchored in vivo. Reproduced with kind permission of the authors.

The principal challenge of permanent magnet technology is the lack of control over the magnet’s strength or attractive force which varies non-linearly with separation to its mating material. Electromagnets, which are controlled by an electrical current, tend to be relatively complex to control and more bulky than permanent magnets. A hybrid approach which combines the best of both technologies would appear ideally suited for a number of the applications examined (e.g., retraction, anchoring, feeding tube placement).

Magnetic compression anastomosis is the best understood and most common therapeutic application of magnets. However clinical outcomes such as repeatability, circumferential integrity of the anastomosis, and comparative assessment against hand-sewn or stapled anastomosis need to be better understood before these techniques become more widespread. The long term safety of magnetic devices remains a concern while uncertainty in the global supply of neodymium should not be underestimated by medical device manufacturers.

Our research group has recently reported (Tugwell et al., IEEE Trans Biomed Eng. 2015 Mar; 62(3):842-8) the first use of electropermanent magnet technology for surgical retraction ( in the pre-clinical setting. This technology, which combines the form factor of permanent magnets with the controllability of electromagnets, may be suitable for further investigation across a number of therapeutic applications in surgery and endoscopy.

Read the abstract for this article here.

The information presented in Endoscopedia reflects the opinions of the authors and does not represent the position of the American Society for Gastrointestinal Endoscopy (ASGE). ASGE expressly disclaims any warranties or guarantees, expressed or implied, and is not liable for damages of any kind in connection with the material, information, or procedures set forth.

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