Repeat Mri Within 90 Days in Patients with Spine Infections Does Not Lead to a Change in Patient Management: A Retrospective Study.

BACKGROUND: Spine infections are associated with significant morbidity and mortality. Despite Infectious Diseases Society of America (IDSA) guidelines recommending treatment be assessed through clinical examination and inflammatory markers rather than routine magnetic resonance imaging (MRI), repeat MRIs are frequently obtained. The clinical utility and consequences of repeat MRI in this setting remain unclear. METHODS: We performed a retrospective singleinstitution study of adult patients with infectious spine pathology who underwent repeat MRI between January 2019 and December 2023. Patients were stratified by timing of repeat MRI (≤90 days vs >90 days from index MRI). The primary outcome was surgical intervention prompted by repeat MRI findings. Secondary outcomes included changes in physical examination prior to repeat MRI, need for fast-acting anxiolytic medication, and acute kidney injury. RESULTS: A total of 222 repeat MRIs were identified in 141 patients. Of these, 163 (73%) were performed ≤90 days and 59 (27%) were performed >90 days from the index MRI. Patients undergoing repeat MRI >90 days were significantly more likely to undergo spine surgery (p=0.04) and to have a documented change in physical examination prior to imaging (p<0.001). Repeat MRI ≤90 days was not associated with increased surgical intervention. Overall, 30% of repeat MRIs required pre-procedure anxiolytic medication, with higher rates in the ≤90-day cohort (p=0.04). AKI occurred after 9/164 (5%) repeat MRIs, with no difference between groups. CONCLUSION: Repeat MRI within 90 days in patients with spine infections rarely alters surgical management and is often obtained in the absence of clinical deterioration. Clinical examination appears to be a more reliable indicator of treatment response. These findings support IDSA guidelines recommending selective use of repeat MRI and highlight potential patient-centered consequences of unnecessary imaging.Level of Evidence: III.