Magnetic Resonance Imaging Distortion and Targeting Errors from Strong Rare Earth Metal Magnetic Dental Implant Requiring Revision

Özet

Recently, the use of magnetic dental implants has been re-popularized with the introduction of strong rare earth metal, for example,neodymium, magnets. Unrecognized magnetic dental implants can cause critical magnetic resonance image distortions. We reporta case involving surgical failure caused by a magnetic dental implant. A 62-year-old man underwent deep brain stimulation formedically insufficiently controlled Parkinson’s disease. Stereotactic magnetic resonance imaging performed for the first deep brainstimulation showed that the overdenture was removed. However, a dental implant remained and contained a neodymium magnet,which was unrecognized at the time of imaging; the magnet caused localized non-linear distortions that were the largest around thedental magnets. In the magnetic field, the subthalamic area was distorted by a 4.6 mm right shift and counter clockwise rotation.However, distortions were visually subtle in the operation field and small for distant stereotactic markers, with approximately 1–2mm distortions. The surgeon considered the distortion to be normal asymmetry or variation. Stereotactic marker distortion wascalculated to be in the acceptable range in the surgical planning software. Targeting errors, approximately 5 mm on the right sideand 2 mm on the left side, occurred postoperatively. Both leads were revised after the removal of dental magnets. Dental magnetsmay cause surgical failures and should be checked and removed before stereotactic surgery. Our findings should be consideredwhen reviewing surgical precautions and making distortion-detection algorithm improvements.