Aug 2018 Medical Design & Outsourcing
The FDA has given Envoy Medical’s Esteem middle-ear implant clearance for MR-conditional labelling in both 1.5 and 3.0 Tesla (T) scanning environments. Envoy introduced the Esteem, the first fully implantable device to treat hearing loss in the U.S., in 2010. Surgeons and audiologists who work closely with hearing implants are often asked about a device’s compatibility with MRI. It has been seen as a limitation of middle ear implants that all of them were contra-indicated for “high-resolution” 3.0 T scans, and all but one were also contra-indicated for 1.5 T.
“MRI scans are widely used and seen as a preferred imaging tool across a variety of situations,” Brent Lucas, Envoy Medical’s CEO, said in a prepared statement. “We did not want people to have to make a choice between our device and the chance that they will need an MRI in the future. MR-conditional approval at both 1.5 and 3.0 Tesla gives Esteem patients the peace of mind that they can safely undergo certain MRIs without having to endure the additional surgeries, hassles, and costs to have the device partially or fully removed beforehand.”
Patient safety during MRI scans is clearly the most important consideration when talking about whether an implantable medical device can undergo an MRI scan. Another important concern is the quality of the resulting image and how much distortion or “artifact” was created by the implanted medical device being present in the body. “Most other implanted hearing devices contain magnets for one purpose or another. Some have a magnet that directly interacts with the middle ear bones while others have a magnet under the scalp to hold an external sound processor in place,” said Paul Mazanec, Envoy Medical’s chief technology officer. “The Esteem does not contain any implanted magnets, which obviously reduces safety and comfort risks associated with magnetic coupling during MRI, but it also helps minimise the amount of image distortion around the implant. It is one thing to be able to get an MRI with an implant, that’s obviously great, but it is even better to know that the implant you have causes less image distortion and artifact than other devices around the implant itself, especially if you need an MRI of the head or neck.”