Utility of Preoperative Magnetic Resonance Imaging Myelography for Identifying Dural Defects in Patients with Spinal Extradural Arachnoid Cysts: Case Report

OBJECTIVE: Preoperative magnetic resonance imaging (MRI) myelography scans demonstrated a dural defect in a 50-year-old man with an epidural arachnoid cyst who had a 29-year history of untreated weakness and numbness in both lower limbs. METHODS: MRI scans showed a dorsal intraspinal extradural cystic lesion at the level from Th11 to L1. Although preoperative cine-MRI scans failed to display the dural defect, an MRI myelography scan showed cerebrospinal fluid in the subarachnoid space containing a cyst. RESULTS: The site of shunting between the subarachnoid space and the cyst was visualized as a pulsating flow, void to the right of Th12. We removed the cyst wall and closed the dural defect via laminectomy. CONCLUSION: Because the preoperative MRI myelography scan correctly identified the existence and location of the dural defect, we conclude that MRI myelography is helpful for detecting dural defects in patients with epidural arachnoid cysts.