Computational Study of the Effect of Orthopedic Plates on Gradient Field-Induced Peripheral Nerve Stimulation in MRI

Motivation: To understand whether orthopedic plates implanted in patients affect the risk of peripheral nerve stimulation (PNS) induced by MRI gradient fields. Goal(s): To assess if activation thresholds for PNS are altered by the presence of nearby orthopedic plates. Approach: A combined approach of using anatomical electromagnetic and neurophysiological modeling was employed to evaluate the stimulation threshold for specific nerves, both with and without the implanted plate. Results: Orthopedic implants can significantly reduce nerve stimulation thresholds by up to 80%. Some reduced thresholds were close to PNS safety limits, indicating a notably lower safety margin for patients with implants compared to those without. Impact: The observed reduction in PNS thresholds suggests that individualized risk assessments may be necessary for MRI screenings of patients with orthopedic implants.