Magnetic resonance imaging of stapes prostheses.
OBJECTIVE
To assess the magnetic resonance imaging (MRI) compatibility of stapes prostheses.


METHODS
A comprehensive review of the English literature evaluating MRI compatibility of stapes prostheses. Multiple series of stapes prostheses from different manufactures placed in a 1.5-tesla MRI field to determine ferromagnetic properties.


RESULTS
When MRI was first introduced, reports demonstrated the MRI compatibility of stapes prostheses. The testing was performed on single copies of various prostheses from several manufacturers. Although implant manufacturers have indicated MRI compatibility, several reports of variable ferromagnetic properties of aneurysm clips have been reported. This variability has led to rotation of the clips and hemorrhage in patients with supposed MRI-compatible clips. These findings suggest that testing single stapes prostheses from a manufacturer might not completely assess the safety of MRI on patients with stapes prostheses. We performed MRI compatibility testing on several series of stapes prostheses from Xomed Surgical Products and Smith & Nephew Richards. Two series of Xomed stapes prostheses were found to have ferromagnetic properties.


CONCLUSIONS
Manufacturing variability could lead to stapes prostheses being MRI incompatible. Each prosthesis should be tested before implantation for ferromagnetic properties.
House Ear Clinic and House Ear Institute, Los Angeles, California 90057, USA.
A J
AJ
Syms
G W
GW
Petermann
D003257:Consumer Product Safety; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000009:adverse effects* / Q000379:methods; D008280:Magnetics; D008422:Materials Testing; D009998:Ossicular Prosthesis / Q000145:classification / Q000592:standards* / Q000600:supply & distribution; D011356:Product Labeling; D011474:Prosthesis Design; D011475:Prosthesis Failure