Effects of an extended MRI approval of an implantable spinal cord stimulation device on compliance with manufacturer's recommendations.

Abstract

Objective: The current approval for all available spinal cord stimulation (SCS) devices set several limitations for magnetic resonance imaging (MRI). As a result, most of the necessary examinations are not possible within the scope of the restrictive approvals and, if legally permitted, must be carried out off-label. This retrospective subgroup analysis investigates if the currently extended MRI approval of one specific device allows more MRI scans to be conducted within the manufacturer's recommendations.

Materials and methods: Technical MRI data (saved in the DICOM headers) and medical treatment data for all MRI examinations on patients with Proclaim® implantable pulse generators (IPG; Proclaim® spinal cord stimulation systems, Abbott Laboratories, Plano, TX, USA) were examined. Due to a major change in our standard operating procedures for MRI scans in 2019, the two time periods (before and after 2019) were separately analyzed.

Results: We identified 62 MRI scans with the IPG. The entire implanted system was approved for MRI examinations in just over 50% of the cases, regardless of old and new approval. Options for lead placement were expanded in the new approval; however, this did not significantly improve the number of MR conditional devices. By contrast, for a higher specific absorption rate, significantly more scans within the recommendations are possible in Period 2 (p = 0.011). However, the number of possible scans did not reach statistical significance in Period 1 (p = 0.078). No device-related adverse events were noted.

Conclusion: The new MRI approval is suitable for performing more scans within the manufacturer's specifications. Cervical leads remain problematic because longer leads are required, and the lower impedances inhibit the MRI mode.