Research Professor, Clinical and Applied Anatomy and Pathology
Uppsala University Hospital
Uppsala, Sweden
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Axial section through a severely
degenerated L3–L4 disc of a 70–year–old man who had presented with a
history of low back pain and several episodes of transient radicular
pain in his forties. The facet joints are markedly degenerated and
display advanced reactive hypertrophic changes, rendering the facet
joints a ball–and–socket configuration. This joint hypertrophy
narrows the spinal canal from side to side, but it also severely
encroaches on the neuroforamina which are practically obliterated by
the intrusion of the superior articular processes from below (this
phenomenon is well illustrated in sagittal SLIDE 19). Note also the
ectopic bone fragment in the ligamentam flavum insertion site to the
left (enthesopathy = ligament insertion site ossification). The
discs bulges circumferentially and markedly contributes to foramen
obliteration and encroachment on the spinal canal anteriorly. On
both sides of the midline, old defects of the disc are now invaded
by pink–colored granulation tissue which in turn is surrounded by
white metaplastic disc matrix. The granulation tissue is probably
the result of "neovascularization" of the disc from the epidural
space through clefts or defects in the outer annulus fibrosus.
Neovascularization tissue is highly vascular and cellular
(fibroblasts) and therefore gives rise to signal changes on MR,
especially after Gadolinium contrast enhancement.
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©2000 Wolfgang Rauschning, M.D., Ph.D.
Professor of Clinical Anatomy
Academic
University Hospital
Department of Orthopaedic Surgery
Uppsala, Sweden
Reproduction without permission is prohibited
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