Surgical Strategies in the Management of Sequestrated Disc Herniations in the Lumbar and Cervical Spines

Abstract

Orief et al. have reported six cases of sequestrated disc herniation, five in the lumbar spine and one in the cervical spine, which regressed in the follow-up magnetic resonance imaging (MRI) corresponding to neurological improvement. We also experienced the same kind of cases of cervical and lumbar disc herniations in the repeated MRI several months after the initial study. With their thorough review of the literature, they concluded that the possible mechanism of resorption of the sequestrated disc was dehydration and inflammationmediated resorption as a foreign body in the vascular-rich epidural space, which seemed to be quite reasonable. Ahn et al. (1) reported an interesting observation on effect of the transligamentous lumbar disc herniation on their regression and clinical outcome. Of 36 patients with symptomatic lumbar disc herniations that were treated conservatively and followed up by MRI, 25 decreased in size. Ten (56%) of 18 subligamentous herniations, 11 (79%) of 14 transligamentous herniations, and all 4 (100%) of sequestrated herniations were reduced in size. The authors concluded that transligamentous extension of herniated discs through the ruptured ligament was important to its reduction in size than its initial size of the herniated discs. Komori et al. (3) emphasized the importance of contrast-enhanced MRI in conservative treatment of lumbar disc herniations. In all cases of migrated discs, circular enhancement was visualized on contrastenhanced MRI, and 17 (77%) of 22 cases showed gradual thickening of enhanced area and decrease in size of migrated discs. The herniated discs disappeared in nine and markedly decreased in seven, corresponding to their good clinical course of sciatica. They concluded that contrast-enhanced MRI was a useful prognostic parameter.