Delayed-Onset Leg Weakness Caused by Posterior Migration of a Herniated Disc to the Thecal Sac Mimicking Epidural Hematoma in a Flexion-Distraction Injury of the Lumbar Spine: A Case Report / 대한척추외과학회지

STUDY DESIGN: Case report. OBJECTIVES: To document the first known case of posterior migration of a herniated disc in a lumbar flexion-distraction injury. SUMMARY OF LITERATURE REVIEW: Lumbar disc herniation is sometimes confused with epidural hematoma, especially when the disc migrates posterior to the thecal sac. There has been no report of posterior migration of a herniated disc after a lumbar flexion-distraction injury. MATERIALS AND METHODS: A 47-year-old woman with no pertinent medical history was diagnosed with a flexion-distraction injury of the L2–L3 vertebrae after a motor vehicle accident. The patient had no neurological deficit initially. Magnetic resonance imaging (MRI) showed a space-occupying lesion with T2 hyperintensity and T1 isointensity on the dorsal side of the thecal sac at L2–L3. After posterior lumbar fixation and fusion, progressive leg weakness occurred 1 week postoperatively. RESULTS: A second operation revealed no evidence of epidural hematoma, but a sequestrated disc. Decompression and sequestrectomy were performed, and the patient's neurological status had recovered fully at 4 months postoperatively. CONCLUSIONS: This case highlights the potential for posterior migration of a herniated disc with flexion-distraction injuries of the thoracolumbar spine. Discontinuity of the posterior annulus fibrosus on MRI may aid the distinction of posterior migration of a herniated disc from epidural hematoma. Because posterior migration of a herniated disc is associated with progressive neurological deficits, surgeons must consider decompression surgery when such herniation is suspected, even in the absence of neurological symptoms.

Analysis of the Risk Factors for Posterior Migration of Single Cage after Transforminal Lumbar Interbody Fusion / 대한정형외과학회잡지

PURPOSE: To analyze the risk factors for posterior migration of a single cage after transforminal lumbar interbody fusion (TLIF). MATERIALS AND METHODS: This study was conducted retrospectively on 48 patients (60 discs) who were followed-up for 1 year after TLIF from January 2015 to January 2017. The patients were divided into two groups: group 1 containing 16 patients (17 discs) with cage migration and group 2 containing 32 patients (43 discs) without it. Information related to cage migration, such as the demographic factors, shape of disc, level and location of the cage inserted, and disc height change, was acquired from the medical records and radiologic images, and the possibility for generating posterior migration of cage was evaluated statistically. RESULTS: The demographic factors and cage-inserted level were similar in the two groups (16 patients in group 1, 32 patients in group 2). In the migration group, number of patients with a pear-type disc, 9 patients, was significantly larger; the disc height change, 1.8 mm, was significantly smaller; and the cage was located frequently on non-center in the anteriorposterior view and center in the lateral view in 9 and 15 out of 16 patients, respectively. CONCLUSION: A pear-type disc shape, small disc height change, cage with non-center on the anteriorposterior view and non-anterior on the lateral view are the risk factors for posterior migration. These factors are important for preventing posterior migration of the cage.

Paraparesis due to Posterior Migration of Ruptured Disc in the Adjacent Segment after Spinal Fusion: Unusual Junctional Problem / 대한척추외과학회지

Posterior epidural migration of sequestered lumbar disc fragments is an uncommon event. We present here an especially uncommon case involving a patient with paraparesis that was due to posterior migration of a ruptured disc in the adjacent segment after spinal fusion. The patient had a herniated lumbar disc in a diseased spinal junction with sequestered fragments that were located posterior to the thecal sac.

Posterior Epidural Migration of a Sequestrated Intervertebral lumbar Disc with Cauda Equina Syndrome: Two Cases Report / 대한척추외과학회지

Posterior epidural migration of a sequestrated intervertebral lumbar disc with cauda equina syndrome is quite rare. This paper reports two unusual cases of posterior epidural migration of a sequestrated intervertebral lumbar disc with cauda equina syndrome to emphasize the importance of early diagnosis and complete decompression.

Posterior Migration of Extruded Lumbar Disc Fragments

HNP (Herniation of the necleus pulposus) generally occurs at ventral portion of lumbar thecal sac due to the anatomical position. We report two unusual cases of herniated dorsal portion of lumbar thecal sac causing diagnostic difficulties. Two patients with posteriorly migrated epidural disc fragments were evaluated with plain X-ray, and magnetic resonance imaging. These patients responded well to operation with complete relief of symptoms. Definite diagnosis of posteriorly located disc fragments is difficult because the radiological images of disc fragments may mimic those of other more common posterior epidural lesions.