Posterior epidural migration of a lumbar disc fragment: a series of 6 cases

Abstract

<jats:sec> <jats:title>Object</jats:title> <jats:p>The migration of a lumbar intervertebral disc fragment to the posterior epidural space is a rare complication of lumbar disc herniation (LDH), mostly diagnosed intraoperatively. The authors describe a series of 6 patients with a posterior epidural migration of a lumbar intervertebral disc fragment (PEMLIF) and provide a systematic review of the literature.</jats:p></jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>The authors undertook a retrospective case series of patients with PEMLIF who underwent surgery for LDH between February 2007 and June 2010. In 6 (1.04%) of 572 patients a diagnosis of PEMLIF was established. In addition, a systematic review of the literature produced 41 additional cases reported since 1973. The authors analyzed epidemiological, clinical, and imaging features, as well as surgical treatment and outcome of this infrequent form of LDH.</jats:p></jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>This study represents the largest case series to analyze the distinguishing features of PEMLIF. Including the authors' cases, 37 male (78.72%) and 10 female (21.28%) patients (mean age 54.08 years) appear in the literature. Although the predominant clinical disturbance was related to cauda equina compression in 22 patients (46.80%), 19 patients (40.42%) presented with typical symptoms of sciatica or anterior thigh pain. In 27 patients (57.44%), PEMLIFs were localized at high lumbar levels. Magnetic resonance imaging was used in 36 cases. The PEMLIF appeared iso- to hypointense on T1-weighted imaging and had a variable intensity on T2-weighted imaging. After administration of Gd, 85.71% of lesions exhibited a peripheral ring. The preoperative diagnosis was never related to PEMLIF in 68% of cases. The PEMLIF was totally resected in all patients. An additional discectomy was performed in 31 patients (65.95%). Information was incomplete in 1 case. Of the remaining 46 patients, all improved postoperatively: total recovery was achieved in 33 cases (71.74%), subtotal recovery in 2 cases (4.35%), and improvement in 11 cases (23.91%). The postoperative outcome appeared not to depend on the duration or the degree of preoperative neurological deficits or the size of disc fragment.</jats:p></jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>The migration of a lumbar intervertebral disc fragment to the posterior epidural space is a rare event, occurring in an advanced working-age population. Clinical presentation is indistinguishable from the typical LDH, but overall cauda equina symptoms are far more common. High lumbar levels are more affected. Magnetic resonance imaging characteristics are difficult to differentiate from those of other entities. Ring enhancement after Gd administration is common. Outcomes in patients with cauda equina symptoms appear better than those in patients with standard ventral compression.</jats:p></jats:sec>

PEMLIF—a tale of two stories

“…PEMLIF as quoted in the literature is very rare. A recent review of literature by Akhaddar et al found that the total number of cases was only about 41 (10). This generally occurs in the setting of a degenerating spine pathology and patients usually give a previous history of backache like our second patient.…”

Posterior epidural migration of sequestered lumbar disc fragment causing cauda equina syndrome

“…In PEM of the lumbar disc, men outnumber the female with the ratio of 4 to1 and the patients of middle age are mostly affected 1,5,8,[10][11][12] .…”

“…Decision for urgent surgery should be the first step toward the elimination of pain and averting neurological deficit, particularly in the subjects with cauda equina syndrome. Removal of the sequestrated disc fragment can be achieved through hemilaminectomy 1,5,6 . Hopefully, the outcome is good in majority of the patients suffering from this pathology.…”

“…Review of reported cases revealed that half of the cases were manifested with radiculopathy and the other half with cauda equina syndrome [1][2][3][4][5]8,12 . The plain radiographs does not give too much information, in particular with consideration of disc height which remains normal because of the rapidity of the events in PEM.…”

“…Since these radiological features mimic those of other common posterior epidural lesions, definite preoperative diagnosis cannot be made in all of the cases 3,10 . Differential diagnosis based both on clinical and radiological features include rapid expansion of a pre-existing synovial cyst, hemorrhagic juxtafacet cysts, gout, cystic schwannomas, tumors and abscess 1,[3][4][5]6,[8][9][10] . Decision for urgent surgery should be the first step toward the elimination of pain and averting neurological deficit, particularly in the subjects with cauda equina syndrome.…”