The pathology of ligamentum flavum in degenerative lumbar disease.
METHODS
A pathologic study of the ligamentum flavum in degenerative lumbar disease.


OBJECTIVE
To elucidate the clinical significance of each pathologic finding of the ligamentum flavum.


BACKGROUND
In many reports, researchers observed the ligamentum flavum removed partially during surgery and did not evaluate the whole image of the ligamentum flavum. In addition, there are only a few reports that examined the possible association between various histologic findings and clinical findings. And, thus, there are many unclear points in the clinical significance indicated by each pathologic finding.


METHODS
The study participants were 50 patients with degenerative lumbar diseases who underwent surgical decompression with removal of the ligamentum flavum of the affected spinal level. Tissue specimens of the removed ligamentum flavum in cross section were prepared, and changes in the elastic fibers and collagen fibers were evaluated in three grades to evaluate the whole image. In addition, we observed the presence or absence of any focal lesions and statistically analyzed the possible association between these histologic findings and clinical symptoms or image findings.


RESULTS
In regard to the association between histologic findings and clinical symptoms or image findings, calcification was observed in significantly older patients, who tended to have low scores in preoperative JOA score, and was frequently observed in patients with cauda equina symptoms. Patients with ossification had a significantly greater % slip, and chondroid cells were frequently observed in patients with spondylolisthesis.


CONCLUSIONS
Various pathologic findings provided important foundations for discussing the pathogenesis of lesions in ligamentum flavum. Calcification was frequently observed in elderly patients and those with cauda equina symptoms, and these patients tended to have severer preoperative symptoms. Chondroid cells were frequently observed in patients with spondylolisthesis, and patients with ossification had a greater % slip, suggesting involvement of mechanical load in ossification of ligaments. The pathologic findings were significantly related to the clinical features, and these findings will be profitable for understanding the pathogenesis of degenerative lumbar disease.
Department of Orthopaedic Surgery, Programs for Applied Biomedicine, Division of Clinical Medical Science, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan. teruo@hiroshima-u.ac.jp
Teruaki
T
Okuda
Itsushi
I
Baba
Yoshinori
Y
Fujimoto
Nobuhiro
N
Tanaka
Tadayoshi
T
Sumida
Hideki
H
Manabe
Yuzo
Y
Hayashi
Mitsuo
M
Ochi
D000368:Aged; D002114:Calcinosis / Q000473:pathology; D005260:Female; D006801:Humans; D017843:Ligamentum Flavum / Q000473:pathology*; D008159:Lumbar Vertebrae; D008297:Male; D008875:Middle Aged; D013130:Spinal Stenosis / Q000175:diagnosis / Q000473:pathology*; D013168:Spondylolisthesis / Q000175:diagnosis / Q000473:pathology*