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Neuroradiology Case of the Week

Case 210

Jerry Lee, MD and Per-Lennart Westesson, MD, PhD, DDS

Clinical Presentation: A 57-year-old male with a history of back pain with left sided radiculopathy.

Radiological Findings:

Figure 1. Sagittal T2 weighed imaging demonstrates a single fragment of extruded disk herniation lying posterior to the vertebral body of L3.  It lies between the vertebral body and the posterior longitudinal ligament.

Figure 2. 

Figure 3. 

Figure 4. 

Figure 5.
Axial T2 (Figs. 2 and 3) and T1-weighted imaging (Figs. 4 and 5) demonstrate the fragment posterior to the L3 vertebral body in the left paracentral region extending into the left lateral recess and left neural foramen.

Diagnosis: Free disk fragment (sequestered disk)

Discussion: A free disk fragment is an extruded disk herniation which is no longer in continuity with the parent disk material The sequestered disk fragment may lie at the disk level, either anterior or posterior to the posterior longitudinal ligament, or can migrate inferior to, or less commonly, superior to the parent disk level. Free disk fragments may extend over two disk levels and be multiple in number. The lateral recesses or superiorly into the neural foramina are favorite locations for migration. In about half of the cases, the fragment consists predominantly of nuclear material, and the other half predominantly endplate material. Rarely, free disk fragments may extend into the thecal sac where they are properly referred to as “intradural disk herniations.”

References:

  1. Atlas, SW. Magnetic Resonance Imaging of the Brain and Spine. Vol 2, 3rd ed. 2002, LWW, Philadelphia; pg 1659
  2. Zimmerman RA, Bilaniuk L. Neuroimaging: Clinical and Physical Principles.New York: Springer, 2000.
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