Guy Fierens1,2,3, Nina Standaert4, Ronald Peeters5, Christ Glorieux1, and Nicolas Verhaert3,4
1Physics and Astronomy, KU Leuven, Leuven, Belgium, 2Cochlear Technology Centre Belgium, Mechelen, Belgium, 3Neurosciences, KU Leuven, Leuven, Belgium, 4Otorhinolaryngology, KU Leuven, Leuven, Belgium, 5Radiology, UZ Leuven, Leuven, Belgium
Synopsis
Patients
suffering from disabling hearing loss are often treated via the implantation of
an active auditory implant. Even though the use of MRI is often needed in a
post-operative follow-up or for the diagnosis of other pathologies. Using MRI
in this patient group however raises some concern due to several possible
patient risks. The presented work provides an overview of the most commonly
occurring adverse events by analyzing data reported to the Food and Drug
Administration and the MEDLINE and EMBASE literature databases.
Introduction
Magnetic resonance imaging (MRI) has become the gold-standard for the
diagnosis of many pathologies due to its ability to create high-resolution
images of soft tissue without requiring using ionizing radiation1. Use of MRI in patients with auditory
implants can however raise concern due to mutual interactions between the
implant and the scanner that create a potential patient risk. Over the years,
implantable hearing systems like cochlear implants, middle ear implants and
implantable bone conductors have become an established treatment option for
patients suffering from a disabling hearing loss, leading to an increased
number of patients being implanted1. In addition to the high
likelihood of having to undergo an MRI scan during a patient’s life1,
several of these specific patients require post-operative follow-up using MRI2,3.
In the past two decades, industry and academics have been working
intensely on trying to identify all possible interactions that could lead to
patient harm, including methods how to test the severity and likelihood of
these risks. These efforts have led to the definition of a number of industry
standards, describing which tests an implant manufacturer has to do to
demonstrate device safety4 and how these values should be reported
towards clinicians and patients5,6. In parallel, researchers have
been investigating different methods to characterize7 and mitigate8
patient risk for patients with these type of implants, of which part of these
efforts are summarized in a complete literature review9.
Despite these extensive efforts by both industry and academia, there is
still a risk of patient harm during MRI. The presented work describes the most
common adverse events reported to the Food and Drug Administration (FDA) for
these devices by analyzing data available in the Manufacturer and User Facility
Device Experience (MAUDE) database and adverse events reported in literature by
searching the Medical English Literature database (MEDLINE, U.S. National
Library of Medicine, Bethesda, MD, US) and the Exerpta Medica database (EMBASE,
Elsevier, Amsterdam, NL). Materials and methods
Data
is extracted from the MAUDE database by searching for adverse events within the
last ten years. Literature containing adverse events is extracted from the MEDLINE
and EMBASE databases. Adverse events reported for devices of the four major
auditory implant manufacturers are extracted by searching both for events in
which the manufacturer is given, but also where the manufacturers or their
devices are referenced. Data is further filtered in Matlab (Mathworks, Nattick,
MA, USA) to exclude records not focusing on auditory devices and duplicates. Results and discussion
Complex interactions can occur between an implant and the
electromagnetic fields present during MRI. The magnitude and type of these
interactions affects to which risks a patient with an implant can be exposed
during, before or after scanning. Thanks to the efforts of industry and
academia, many risks can be quantified or mitigated. Nonetheless, there still
remain different risks associated with exposing these patients to an MRI
examination. In part this is the result of the inability to prove safety as
such, but more as an effort to characterize the risk of harm10. Care
must always be taken to minimize patient risk and increase the diagnostic value
of the MRI examination in a clinical setting in addition to the technical
device labels.
Dislocation of the internal magnet remains one of the key reported risks,
together with the induction of discomfort or pain around the implantation site
of the device magnet due to MRI-induced displacement forces. Other risks
include hearing pounding or ringing sounds during MRI or device migration. The
type of adverse events reported to the authorities agrees with findings reported
by other authors1,7,9,11. At the time of writing this document, the interpretation
of the data is ongoing. The complete results of this analysis will be presented
at the conference.Acknowledgements
G. Fierens and N. Standaert have contributed equally to this work.References
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