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.