Sudden onset of cauda equina syndrome resulting from posterior migration of lumbar herniated disc without significant previous neurological signs.

While extruded disc fragments are known to migrate anteriorly, posteriorly, or laterally to the theca sac, posterior migration of the fragments is relatively rare and sudden onset of cauda equina syndrome (CES) caused by the migration is extremely rare. The authors experienced a case of CES that was manifested abruptly with sudden paraplegia caused by posterior migration of the lumbar intervertebral disc. A 74-year old man, who had no prior significant neurologic signs or trauma history, visited our emergency center with paraplegia of both lower extremities occurring suddenly when awakened. On magnetic resonance image (MRI) findings, we could detect ruptured disc herniation with severe lumbar stenosis at the L2-3 level. We performed an emergent decompression, and the right posterior migrated disc fragments at L2-3 were intraoperatively observed. The patient was fully recovered himself on the follow up after 3 months of the operation. In conclusion, early operation can result in better outcome in acute paraplegia caused by the posterior migrated disc fragments.