An Unusual Intraoperative Lumbar Disc Herniation Migrating into the Posterior Epidural Space

Abstract

Background: The migration of a herniated fragment of the intervertebral disc towards posterior epidural space remains an exceptional phenomenon and Its clinical presentation is not unequivocal. Its diagnosis in modern imaging can cause confusion with other lesions of the posterior epidural space. We report an unusual migration of a herniated disc fragment into the posterior epidural. Method: we describe a case of an unusual migration of disc fragment into the posterior epidural space admitted in Neurosurgery department of University Teaching Hospital of Cotonou in 2019. Result: A 33-year-old man was admitted for progressive bilateral radiculopathy, gait disturbances and constipation. The clinical examination noted a moderate perineum and right buttock hypoesthesia, a flaccid paraparesis, bilatéral straight leg raising limitation (45°). The right patellar and achilean reflexes were depressed. MRI of the lumbar spine showed a right L4L5 herniated disc and its migration into the anterolateral epidural space. Surgery was performed with posterior approach. After an L4 and L5 laminectony, we discovered a very compressive large fragment of L4L5 intervertebral disc. The fragment was delicately dissociated from its dural adhesions. Histological examination confirmed the fibrocartilaginous nature of the sample. The post-operative period was uneventful. Three months post-operatively, he had regained his autonomy with a strength score of 5/5 in both pelvic limbs. Conclusion: Migration of intervertebral disc fragment into the posterior epidural space is a rare phenomenon. Diagnosis errors are possible. In case of posterior migration with cauda equina syndrom, we recommend laminectomy with removal of herniated disk fragment. This approach remains a simple and secure.