A J Syms1, G W Petermann. 1. House Ear Clinic and House Ear Institute, Los Angeles, California 90057, USA.
Abstract
OBJECTIVE: To assess the magnetic resonance imaging (MRI) compatibility of stapes prostheses. DATA SOURCES: 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. CONCLUSION: Manufacturing variability could lead to stapes prostheses being MRI incompatible. Each prosthesis should be tested before implantation for ferromagnetic properties.
OBJECTIVE: To assess the magnetic resonance imaging (MRI) compatibility of stapes prostheses. DATA SOURCES: 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. CONCLUSION: Manufacturing variability could lead to stapes prostheses being MRI incompatible. Each prosthesis should be tested before implantation for ferromagnetic properties.