Sequestrated lumbar intervertebral disc in the posterior epidural space: a report on two cases and review of the literature

BackgroundPosterior epidural migration is an interesting but rare path taken by a prolapsed intervertebral disc fragment. There are only seven cases reported of a similar migration of the disc fragment in the lumbar spine.PurposeTo diagnose the unusual presentation and interpretation of the sequestrated disc in the posterior epidural space.Study designCase report.MethodsTwo cases of migration of the sequestrated disc into the posterior epidural space are presented. In one patient there was weakness of the ankle dorsiflexors, foot invertors, and toe extensors of the left foot, with sensory loss over the back of the calf and over the lateral three toes. The left ankle jerk was also absent. However, in the other case, there was no objective evidence of neurological deficit distally.ResultsGadolinium magnetic resonance imaging scans showed ring enhancement preoperatively. Biopsy of the specimen taken from surgery confirmed it to be sequestrated disc fragment.ConclusionDiagnosis of posterior epidural migration of the sequestrated discs may be difficult. It may present with subtle clinical features even though the disc transgresses through numerous anatomic restraints including the nerve roots in such cases.