Assessing The Predictive Efficacy of Preoperative MRI Findings in Determining the Location of Dural Defects Associated with Spinal Extradural Arachnoid Cysts

Purpose To evaluate the diagnostic utility of four preoperative MRI findings in identifying the location of dural defects associated with spinal extradural arachnoid cyst (SEAC) to optimize surgical planning. Materials and Methods Fifteen patients with symptomatic SEAC who underwent surgery between 2003 and 2023 were analyzed retrospectively. The following preoperative MRI features were independently evaluated by two radiologists: the septation sign, extraforaminal extension with or without bone remodeling, the C-sign, and the flow-void sign. The accuracy of each finding in predicting the location of surgically confirmed dural defects was assessed. Results The septation sign was observed in all patients (100%), with the accuracy of predicting the location of the dural defect ranging from 80% to 87%. Extraforaminal extension was also identified in all patients, with a similar accuracy of (80%–87%). The C-sign and flow-void signs were less frequently observed (40%–47% and 47%–93%, respectively), with accuracies in predicting the dural defect location ranging from 71%–83% and 71%–79%, respectively. Inter-reader agreement was highest for the C-sign and flow-void sign (100%), followed by extraforaminal extension (93%) and the septation sign (80%). Conclusion Recognition of MRI features—the septation sign, extraforaminal extension with or without bone remodeling, the C-sign, and the flow-void sign—may aid in localizing dural defects. These imaging markers may support surgical planning for SEAC.