MRI safety of the floating mass transducer

MRI scanning in patients implanted with a vibrant soundbridge

“…One patient had bilateral implants, with FMT fixation at the stapes head. Surprisingly, the patient with the bilateral stapes head coupling described no subjective loss of system function, which could have been quite likely as per the results of the temporal bone study 3. It was necessary to refit the AP in this case as well as others (6 out of 12 [50%]).…”

“…The VSB was previously investigated in vitro, where it was found that changes to the FMT position in the middle ear and the transfer function can occur, but no disarticulation of the ossicular chain was found at 1.5 T 3, 4. A report on two patients described no effect on the transfer function, although an acoustic effect was reported with the MRI scanning at 1.5 T 7…”

“…If the FMT is attached to the stapes head, the round window or the oval window, those patients with preoperative different types of mixed hearing loss are good candidates. In vitro observations (temporal bone experiments) have described positional changes of the FMT after MRI scanning, which can impair the transfer function 3. Microscopic observations3 and force measurements in fresh temporal bones4 showed no changes to the ossicular chain integrity from an MRI scan.…”

“…In vitro observations (temporal bone experiments) have described positional changes of the FMT after MRI scanning, which can impair the transfer function 3. Microscopic observations3 and force measurements in fresh temporal bones4 showed no changes to the ossicular chain integrity from an MRI scan. However, the in vitro findings cannot be completely transferred to the in vivo situation.…”

In vivoexperiences with magnetic resonance imaging scans in Vibrant Soundbridge type 503 implantees

“…The Vibrant Soundbridge 502 was initially investigated in vitro . It was observed that changes can occur to the floating mass transducer position in the middle ear and to the transfer function, but no disarticulation of the ossicular chain was found at 1.5 T 8 , 9…”