Mri Of Migrated Polyethylene Insert Of Mobi-C Implant

HomeRadiologyVol. 300, No. 3 PreviousNext Reviews and CommentaryFree AccessImages in RadiologyMRI of Migrated Polyethylene Insert of Mobi-C ImplantTae Ran Ahn , Ji Young JeonTae Ran Ahn , Ji Young JeonAuthor AffiliationsFrom the Department of Radiology, Gil Medical Center, Gachon University College of Medicine, 21 Namdong-daero, 774 beon-gil, Namdong-gu, Incheon 21565, Republic of Korea.Address correspondence to T.R.A. (e-mail: [email protected]).Tae Ran Ahn Ji Young JeonPublished Online:Jul 13 2021https://doi.org/10.1148/radiol.2021204734MoreSectionsPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In A 47-year-old man visited the emergency department because of abrupt bilateral lower-leg paralysis and decreased anal tone. He had undergone artificial disk replacement of the cervicothoracic junction, or C7–T1, with Mobi-C (Zimmer Biomet) 2 years before. Compressed sensing slice encoding for metal artifact correction sequence MRI of the cervical spine showed posterior migration of the polyethylene insert and resulting cord compression (Figure). The patient underwent emergency surgery where posterior migration of the polyethylene insert was found. A T1 corpectomy with prosthesis removal was successfully performed. After surgery, he underwent rehabilitation for moderate disability with a modified Rankin Scale score of 3 points.Images in a 47-year-old man who visited the emergency department because of abrupt bilateral lower-leg paralysis and decreased anal tone. He had undergone artificial disk replacement of the cervicothoracic junction, or C7–T1, with Mobi-C (Zimmer Biomet) 2 years before. (a) T2-weighted compressed sensing slice encoding for metal artifact correction MRI scan shows posterior and inferior migration of low-signal-intensity polyethylene insert (arrow) in C7–T1 and resulting cord compression and myelopathy. Small amount of anterior epidural fluid is noted inferior to polyethylene insert. (b) Plain radiograph shows superior and inferior metallic endplates in place, but radiolucent polyethylene insert is not visible. (c) Photograph of Mobi-C implant shows central polyethylene insert between two metal plates.Download as PowerPointOpen in Image Viewer The Mobi-C implant consists of a cobalt-chromium alloy endplate with a polyethylene insert (1). At radiography and CT, respectively, each endplate appears radiopaque and has high attenuation, and the polyethylene insert appears radiolucent and has low attenuation. On MRI scans, the polyethylene insert appears with low signal intensity in all pulse sequences (2). Here, the slice encoding for metal artifact correction sequence could help evaluate spinal postoperative prosthetic failure properly by reducing geometric distortion of the metallic implant. There is one previous publication of this complication that was diagnosed with CT myelography (3).Disclosures of Conflicts of Interest: T.R.A. disclosed no relevant relationships. J.Y.J. disclosed no relevant relationships.References1. Petscavage-Thomas JM, Ha AS. Imaging current spine hardware: part 1, cervical spine and fracture fixation. AJR Am J Roentgenol 2014;203(2):394–405. Crossref, Medline, Google Scholar2. Li AE, Sneag DB, Miller TT, Lipman JD, Padgett DE, Potter HG. MRI of Polyethylene Tibial Inserts in Total Knee Arthroplasty: Normal and Abnormal Appearances. AJR Am J Roentgenol 2016;206(6):1264–1271. Crossref, Medline, Google Scholar3. Pitsika M, Nissen J. Spinal cord compression due to nucleus migration from Mobi-C total disc replacement. Br J Neurosurg 2020.10.1080/02688697.2020.1716942. Published online January 24, 2020. Crossref, Medline, Google ScholarArticle HistoryReceived: Dec 30 2020Revision requested: Jan 25 2021Revision received: Jan 30 2021Accepted: Feb 4 2021Published online: July 13 2021Published in print: Sept 2021 FiguresReferencesRelatedDetailsRecommended Articles CT Myelography: Clinical Indications and Imaging FindingsRadioGraphics2020Volume: 40Issue: 2pp. 470-484Postoperative Spinal CT: What the Radiologist Needs to KnowRadioGraphics2019Volume: 39Issue: 6pp. 1840-1861Nontraumatic Spinal Cord Compression: MRI Primer for Emergency Department RadiologistsRadioGraphics2019Volume: 39Issue: 6pp. 1862-1880Spinal Hematomas: What a Radiologist Needs to KnowRadioGraphics2018Volume: 38Issue: 5pp. 1516-1535Fundamentals of Radiation Oncology for Treatment of Vertebral MetastasesRadioGraphics2021Volume: 41Issue: 7pp. 2136-2156See More RSNA Education Exhibits CT Myelography: From Technical Aspects to Imaging EvaluationDigital Posters2022Imaging Assessment Of Foreign Bodies In Head And Neck: Classification And Pictorial GuideDigital Posters2021The Postoperative Spine: A Basic Understanding of Spine Surgical ProceduresDigital Posters2019 RSNA Case Collection Spinal epidural abscess RSNA Case Collection2020Cobb syndromeRSNA Case Collection2021Hirayama DiseaseRSNA Case Collection2021 Vol. 300, No. 3 Metrics Altmetric Score PDF download