Comparison of MRI Artifacts of Cervical Disc Replacements Presented at ISASS 2020
Comparison of MRI Artifacts of Cervical Artificial Discs
Pierce Nunley, MD1; Domagoj Coric, MD2; Olivier Clerk-Lamalice, MD-MSc, FRCPC, FIPP3; Kelly Frank, MS1; Marcus Stone, PhD1
1 Spine Institute of Louisiana; 2 Carolina Neurosurgery & Spine Associates; 3 University of Alberta
Presented at the International Society for the Advancement of Spine Surgery (ISASS), February 26, 2020
Cervical disc arthroplasty (CDA) devices currently on the market include significant metallic components that lead to MRI artifacts. These artifacts can obstruct important anatomy (e.g. neural foramen and spinal cord), causing difficulties in post-operative diagnosis. Spinal implants comprised of PEEK have gained favor, in part due to the reduced MRI artifacts. The first PEEK/ceramic CDA is currently undergoing Food and Drug Administration Investigational Device Exemption (IDE) trials. Comparison of MRI artifacts between different CDA devices has not been previously reported in the literature.
This is a retrospective review of patients that received a CDA device at one or two contiguous levels and a post-operative MRI from three centers participating in the PEEK/ceramic CDA device IDE trials. MRI artifacts from four CDA devices were compared to the PEEK/ceramic CDA.
MRIs were performed on 1.5 T MRI machines and included axial T1-weighted, axial T2-weighted, sagittal STIR, sagittal T1-weighted, and sagittal T2-weighted views. The artifacts were measured by a radiologist blinded to the CDA device. Artifact was defined as the distance between the device boundary and the fringe of the artifact in the anterior-posterior (AP) direction (ASTM F2119); calculated as half the difference between the maximum measured AP distance of the artifact minus the AP footprint of the CDA device.
A total of 46 CDA devices comprised of titanium/polyurethane (5 levels), titanium/UHMWPE (10 levels), CCM/UHMWPE (15 levels), titanium ceramic composite (5 levels), and the investigational PEEK/ceramic composition (11 levels) were evaluated.
The investigational PEEK/ceramic device’s artifacts were statistically significantly smaller (p<.05) than those of other evaluated devices (Fig 1). The mean artifacts for other devices ranged from 3.2mm to 6.3mm, and the mean artifacts for the PEEK/ceramic device were ≤ 0.8mm.
The investigational PEEK/ceramic CDA device had statistically smaller MRI artifacts, allowing improved visualization of the surrounding spinal/neural structures and neural foramen on post-operative MRI (Fig 2).
Fig 1: Antero-posterior measurement of artifacts for axial T1, axial T2, sagittal STIR, sagittal T1, and sagittal T2-weighted MR images.
Fig 2: A) Sagittal T2 sequence shows artifacts related to C6-C7 CCM/UHMWPE CDA. B) Sagittal T2 sequence shows artifacts related to C5-C6 PEEK/ceramic CDA.