Background: There is increasing evidence that spinal cord injury without radiologic abnormalities (SCIWORA) is underreported in adults. The increasing availability of magnetic resonance imaging (MRI) has added substantial information, but there remains considerable disagreement concerning definition as well as diagnostic and therapeutic measures. Furthermore, the interpretability of the literature is constrained by the lack of a reliable classification system based on the morphologic abnormalities visualized by MRI. A comprehensive systematic review was performed to identify all the data published concerning adults experiencing SCIWORA. To assess a potential correlation between clinical and imaging findings, we developed a novel MRI classification system.
Methods: Database searches were conducted for studies on SCIWORA in adults using PubMed and OvidSP. Inclusion criteria were (1) traumatic spinal cord injury with neurologic deficit, (2) absence of fractures and/or dislocations of the spinal column, and (3) a mature skeleton. Data collected included clinical and radiologic findings. MRI patterns and clinical course were correlated.
Results: Sixty-three articles reporting 1,393 patients were identified, of which 44 studies reported 1,132 cases with MRI imaging. At admission, neurologic deficit assessed by the American Spinal Injury Association impairment scale (AIS) in 567 patients was A in 19.1%, B in 18.5%, C in 39.7%, and D in 22.8%. At final follow-up, these were 6.5%, 4.8%, 20.1%, and 44.3%, respectively. In 7.1%, no MRI abnormalities (Type I) were detected, and 92.9% exhibited abnormal scan results (Type II). Of the latter, 11.7% revealed extraneural (Type IIa), 36.9% revealed intraneural (Type IIb), and 44.3% revealed combined abnormalities (Type IIc). Statistical analysis of neurologic impairment at admission and follow-up revealed significant differences in outcome between patients with different imaging findings.
Conclusion: This review emphasizes the prognostic value of spinal MRI for adults with SCIWORA. Using the MRI classification system in future reports will enhance comparability and interpretability and might improve our understanding of the condition.