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Posterior epidural migration of extruded lumbar disk
Surg Neurol 1989;32:31 l-2
311
Brief Communication
Posterior Terry
Epidural Migration
Lichtor,
M.D.,
of Extruded
Lumbar Disk
Ph.D.
Section of Neurological Surgery, The University of Chicago, Chicago, Illinois
Lichtor T. Posterior epidural migration of extruded lumbar disk.
Surg Neurol 1989;32:311-2. Migration of herniated lumbar disks is discussed, and the case of a 61-year-old man with acute lower back pain is reviewed. Free disk fragment; Disk migration
KEY WORDS:
Introduction Herniation fibrosus
of the nucleus pulposus through
in the
lumbar
region
the
is a common
annulus finding.
Some degree of migration has been found in 35% of patients with herniated lumbar disks cl]. The most common path of disk migration is in a posterolateral direction [4], and this migration is restricted by the fibers of the posterior longitudinal ligament. Disk herniations may also occur centrally and laterally. In addition, central disk herniation extending bilaterally has been reported; with these herniations, the lateral extension sometimes involves one or both neural canals. Occasionally, the disk material may penetrate through or around the posterior longitudinal ligament and lie within the epidural fat; in this region the extruded disk may be contiguous with the parent disk or migrate as a separate fragment [I]. Rarely, disk material may penetrate the dura and resemble an intradural tumor. In the cervical region, epidural migration of disk fragments to the anterior and lateral aspects of the cervical spinal canal is also common. There is one reported case, however, of a cervical disk which migrated to the posterior surface of the dural canal 121. This particular disk was calcified extensively, and therefore was thought to be the result of a long-standing disk herniation. There are no reported cases of a lumbar disk which herniated to the posterior surface of the dural sac.
Address reprint requests CO:Terry Lichtor, M.D., Ph.D., Section of Neurosurgery, 2800 West 95th Street, Evergreen Park, Illinois 60642. Received May 4, 1989; accepted June 6, 1989. 0 1989 by Elsevier
Science Publishing
Co., Inc.
Case Report A 6I-year-old man who had undergone a lumbar fusion at the level of L3-L5 10 years previously presented with an acute onset of severe lower back pain radiating to both thighs. The previous surgery was done following a traumatic injury to his back; the myelogram that had been obtained at that time showed no disk herniation. The pain was especially severe on any movement of the lower back, but was not associated with any weakness. There was no improvement with conservative therapy. Neurologic exam was remarkable for radicular pain on straight leg raising of either leg to 45” and some diminished pinprick sensation over the L3 dermatome region bilaterally. In addition, both ankle and knee reflexes were depressed. A magnetic resonance image (MRI) of the lumbar spine was obtained which demonstrated no evidence of disk herniation (Figure 1). However, at the L2-L3 level there was evidence of hypertrophy of the ligamentum flavum along with degenerative facet disease, and a soft tissue density was seen posterior to the dura. A myelogram was then obtained which showed a posterior extradural defect at L2-L3 with anterior compression of the caudal sac, and there was grade 1 spondylolisthesis at this level. A postmyelogram computed tomography (CT) examination demonstrated the presence of an epidural mass with a disk density (90 HU) posterior to the caudal sac at L2-L3 in addition to facet degeneration (Figure 2). This patient was taken to surgery where a wide decompressive laminectomy was done at L2. At the lower aspect of the lamina of L2, the ligamenturn flavum was hypertrophied and removed. Beneath this a soft tissue mass was found and removed; the pathologic examination revealed fibroelastic tissue (ligamenta flava) and nucleus pulposus tissue. Postoperatively the patient’s radicular symptoms completely resolved.
Discussion This is the first reported case of a lumbar disk herniation with migration to the posterior aspect of the caudal sac. 0090.3019/89/$3.50
312
Surg Neural 1989;32:311-12
Lichtor
Figure 1. SagirtaI MRI demonstrates a soft tissue density in the posterior epidural space at L2-L3. There is no evidence for disk herniation.
The surgical treatment for this rare variation of a common problem is certainly straightforward. In this particular patient with a lumbar fusion at L3-L5, there is most likely more movement at the L2-L3 level than that usually encountered; this may therefore lead to disk herniation. However, the origin of this particular herniated disk is not clear. Certainly the MRI examination did not demonstrate disk herniation at any level, and this imaging modality has been shown to be accurate for detecting the interspace of origin in most cases of sequestered lumbar disks [3}. The postmyelogram CT examination was the most sensitive modality in diagnosing this rare case of a herniated lumbar nucleus pulposus.
Figure 2. Postmyelogram CT examination shows extradural material disk density (90 HU) at the L2-L3 level (a.~&, compressing the cauc sac (~z,DE&&) anteriorly. The s&r is in the region of the vertebr body/disk interspace. Facet hypertrophy is also present.
References Fries JW, Abodeely DA, Vijungco JG, Yeager VL, Gaffey WR. Computed tomography of herniated and extruded nucleus pulposus. J Comput Assist Tomogr 1982;6:874-87. Manabe S, Tateishi A. Epidural migration of extruded cervical disc and its surgical treatment. Spine 1986;11:873-8. Masaryk TJ, Ross JS, Medic MT, Boumphrey F, Bohlman H, Wilber G. High-resolution MR imaging of sequestered lumbar intervertebral disks. Am J Roentgen 1988;150:1155-62. Williams AL, Haughton VM, Syvertsen A. Computed of herniated nucleus pulposus. in diagnosis 1980;135:95-9.
tomography Radiology
311
Brief Communication
Posterior Terry
Epidural Migration
Lichtor,
M.D.,
of Extruded
Lumbar Disk
Ph.D.
Section of Neurological Surgery, The University of Chicago, Chicago, Illinois
Lichtor T. Posterior epidural migration of extruded lumbar disk.
Surg Neurol 1989;32:311-2. Migration of herniated lumbar disks is discussed, and the case of a 61-year-old man with acute lower back pain is reviewed. Free disk fragment; Disk migration
KEY WORDS:
Introduction Herniation fibrosus
of the nucleus pulposus through
in the
lumbar
region
the
is a common
annulus finding.
Some degree of migration has been found in 35% of patients with herniated lumbar disks cl]. The most common path of disk migration is in a posterolateral direction [4], and this migration is restricted by the fibers of the posterior longitudinal ligament. Disk herniations may also occur centrally and laterally. In addition, central disk herniation extending bilaterally has been reported; with these herniations, the lateral extension sometimes involves one or both neural canals. Occasionally, the disk material may penetrate through or around the posterior longitudinal ligament and lie within the epidural fat; in this region the extruded disk may be contiguous with the parent disk or migrate as a separate fragment [I]. Rarely, disk material may penetrate the dura and resemble an intradural tumor. In the cervical region, epidural migration of disk fragments to the anterior and lateral aspects of the cervical spinal canal is also common. There is one reported case, however, of a cervical disk which migrated to the posterior surface of the dural canal 121. This particular disk was calcified extensively, and therefore was thought to be the result of a long-standing disk herniation. There are no reported cases of a lumbar disk which herniated to the posterior surface of the dural sac.
Address reprint requests CO:Terry Lichtor, M.D., Ph.D., Section of Neurosurgery, 2800 West 95th Street, Evergreen Park, Illinois 60642. Received May 4, 1989; accepted June 6, 1989. 0 1989 by Elsevier
Science Publishing
Co., Inc.
Case Report A 6I-year-old man who had undergone a lumbar fusion at the level of L3-L5 10 years previously presented with an acute onset of severe lower back pain radiating to both thighs. The previous surgery was done following a traumatic injury to his back; the myelogram that had been obtained at that time showed no disk herniation. The pain was especially severe on any movement of the lower back, but was not associated with any weakness. There was no improvement with conservative therapy. Neurologic exam was remarkable for radicular pain on straight leg raising of either leg to 45” and some diminished pinprick sensation over the L3 dermatome region bilaterally. In addition, both ankle and knee reflexes were depressed. A magnetic resonance image (MRI) of the lumbar spine was obtained which demonstrated no evidence of disk herniation (Figure 1). However, at the L2-L3 level there was evidence of hypertrophy of the ligamentum flavum along with degenerative facet disease, and a soft tissue density was seen posterior to the dura. A myelogram was then obtained which showed a posterior extradural defect at L2-L3 with anterior compression of the caudal sac, and there was grade 1 spondylolisthesis at this level. A postmyelogram computed tomography (CT) examination demonstrated the presence of an epidural mass with a disk density (90 HU) posterior to the caudal sac at L2-L3 in addition to facet degeneration (Figure 2). This patient was taken to surgery where a wide decompressive laminectomy was done at L2. At the lower aspect of the lamina of L2, the ligamenturn flavum was hypertrophied and removed. Beneath this a soft tissue mass was found and removed; the pathologic examination revealed fibroelastic tissue (ligamenta flava) and nucleus pulposus tissue. Postoperatively the patient’s radicular symptoms completely resolved.
Discussion This is the first reported case of a lumbar disk herniation with migration to the posterior aspect of the caudal sac. 0090.3019/89/$3.50
312
Surg Neural 1989;32:311-12
Lichtor
Figure 1. SagirtaI MRI demonstrates a soft tissue density in the posterior epidural space at L2-L3. There is no evidence for disk herniation.
The surgical treatment for this rare variation of a common problem is certainly straightforward. In this particular patient with a lumbar fusion at L3-L5, there is most likely more movement at the L2-L3 level than that usually encountered; this may therefore lead to disk herniation. However, the origin of this particular herniated disk is not clear. Certainly the MRI examination did not demonstrate disk herniation at any level, and this imaging modality has been shown to be accurate for detecting the interspace of origin in most cases of sequestered lumbar disks [3}. The postmyelogram CT examination was the most sensitive modality in diagnosing this rare case of a herniated lumbar nucleus pulposus.
Figure 2. Postmyelogram CT examination shows extradural material disk density (90 HU) at the L2-L3 level (a.~&, compressing the cauc sac (~z,DE&&) anteriorly. The s&r is in the region of the vertebr body/disk interspace. Facet hypertrophy is also present.
References Fries JW, Abodeely DA, Vijungco JG, Yeager VL, Gaffey WR. Computed tomography of herniated and extruded nucleus pulposus. J Comput Assist Tomogr 1982;6:874-87. Manabe S, Tateishi A. Epidural migration of extruded cervical disc and its surgical treatment. Spine 1986;11:873-8. Masaryk TJ, Ross JS, Medic MT, Boumphrey F, Bohlman H, Wilber G. High-resolution MR imaging of sequestered lumbar intervertebral disks. Am J Roentgen 1988;150:1155-62. Williams AL, Haughton VM, Syvertsen A. Computed of herniated nucleus pulposus. in diagnosis 1980;135:95-9.
tomography Radiology