Posterior and anterior epidural and intradural migration of the sequestered intervertebral disc: Three cases and review of the literature

Context: Dorsal migration of the sequestered lumbar intervertebral disc is an unusual and underrecognized pattern of lumbar disc herniation associated with pain and neurological deficit. Findings: Three patients presented with lower limb- and low back pain. MR imaging showed intracanalicular mass lesions with compression of the spinal cord and allowed precise localization of lesions in the extradural or intradural space. Diagnosis was straightforward for the patients with the posterior and anterior epidural disc fragments, whereas various differential diagnostic considerations were entertained for the patient with the intradural mass lesion. All patients underwent surgical removal of the sequestered disc fragments, and recovered full motosensory function. Surgical repair of the dura mater due to CSF leak was required for the patient with intradural disc herniation.