Usefulness of 3D Turbo SE Magnetic Resonance Imaging for Identifying the Dural Defect of Spinal Extradural Arachnoid Cyst—A Case Report—

Abstract

A 25 year old woman presented with progressive pain in the anterior aspect of her left thigh. Neurologically, no objective abnormality was identified. Neuroimaging studies including cine magnetic resonance imaging MRI , magnetic resonance MR myelography, and computed tomography CT myelography showed an extradural cystic mass, probably containing cerebral spinal fluid, at the left lateral intracanalicular space from vertebral levels T12 L2. Although the above methods failed to visualize any dural defect, 3D Turbo SE MRI revealed a possible dural defect adjacent to the left L1 nerve root where neural tissue was somewhat incarcerated. Using a minimally invasive posterior approach L1 hemilaminectomy with partial hemilaminectomy of T12 and L2 , the cyst wall was removed as much as possible. Neural tissue, presumably the cauda equina, protruded into the cyst cavity through the small dural defect. After removing the neural tissue into the dural canal, the dural defect was simply sutured. Fibrin glue was used to reinforce this suture for water tightness. Microscopically, the cyst wall consisted of fibrous tissue with an inner single cell lining. Soon after the surgery, her pain was relieved. No recurrence has been observed so far. In order to carry out minimally invasive surgery for the treatment of an extradural arachnoid cyst, it was necessary to identify dural defect s. However, even by using cine MRI, MR myelography, or CT myelography, the definitive diagnosis was difficult. In our case, 3D Turbo SE MRI was useful for detecting a dural defect. 3D Turbo SE MRI can show multi angle images in a shorter examination time. In view of the form of the dural canal, 3D Turbo SE MRI is feasible in the assessment of a dural defect. Therefore, this neuroimaging method seems to be an indispensable tool for the diagnosis of extradural extra arachnoid cysts.