The origin and fate of herniated lumbar intervertebral disc tissue.
METHODS
In a clinicopathologic study, disc tissue collected from surgery and from cadaveric spines was examined to test an hypothesis about the pathogenesis of herniation.


OBJECTIVE
To determine the origin and fate of herniated lumbar intervertebral disc tissue.


BACKGROUND
Previous studies have ascribed herniated disc tissue to the nucleus, anulus, or endplate, or combinations of the three. One study describes it as newly synthesized fibrocartilage. Regardless of its origin, peripheral neovascularization of disc fragments has been described and may be related to pain symptoms.


METHODS
Disc tissue was collected after extrusion and was examined histologically to determine its origin and fate. To test the hypothesis that sequestration results from migration of isolated, degenerate fragments of nucleus pulposus through preexisting tears in the anulus fibrosus, cadaveric lumbar disc were examined in detail.


RESULTS
Ninety-eight percent of sequestrations contained some nuclear material indicating that nucleus pulposus is the principal substance extruded from the disc. None contained anulus alone. Although vascular repair was present in 89% of specimens, it did not correlate with several clinical parameters.


CONCLUSIONS
The autopsy study confirmed the model of nuclear fragmentation, migration, and extrusion along radiating anular clefts. Neovascularization of extruded fragments bore no relationship with duration of sciatic pain symptoms or clinical outcome.
Division of Tissue Pathology, University of Adelaide, Australia.
R J
RJ
Moore
B
B
Vernon-Roberts
R D
RD
Fraser
O L
OL
Osti
M
M
Schembri
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D005260:Female; D006801:Humans; D007403:Intervertebral Disc / Q000473:pathology*; D007405:Intervertebral Disc Displacement / Q000473:pathology* / Q000601:surgery; D008159:Lumbar Vertebrae / Q000473:pathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009389:Neovascularization, Pathologic / Q000473:pathology*; D010146:Pain / Q000209:etiology