Posterior epidural migration of an extruded free fragment from a lumbar disc herniation

The majority of symptomatic lumbar disc herniations are located in a posterolateral position with resultant nerve root compression. Although caudal, rostral and lateral migrations of disc fragments are common, posterior epidural migration of an extruded free fragment from a lumbar disc herniation is a rare occurrence and sometimes may cause a dural sac compression with cauda equina syndrome. This retrospective case report describes a 63-year-old man with intractable lower back pain and cauda equina syndrome. Emergency magnetic resonance imaging (MRI) revealed a posterior epidural soft tissue compressing the dural sac. The lesion was hypointense on T1-weighted images, hyperintense on T2-weighted images and showed rim enhancement after intravenous injection of gadolinium. A laminectomy at L3 was performed and the extruded disc fragment was removed with dural sac decompression. Postoperatively the patient’s radicular symptoms completely resolved. At the 2-year follow-up visit, the patient had recovered full motor, sensory and urinary functions. MRI is the modality of choice in the evaluation of an extruded free disc fragment and a cauda equina compression. In such cases a wide decompressive laminectomy is recommended.