[Calcification of cervical ligamentum flavum--analysis of calcium compounds and histopathological findings].
We operated 3 patients with cervical myelopathy due to calcification of ligamentum flavum (CLF). Specimens collected surgically were subjected to X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy (Raman) analysis and also histopathological examination. The calcium compounds deposited were calcium pyrophosphate dihydrate (CPPD) in Case 1, apatite in Case 2, and a double-layer structure with an outer CPPD layer and an inner carbonate apatite layer in Case 3. Histopathologically, CPPD deposition in Case 1 could be distinguished from apatite deposition in Case 2 and 3 by hematoxylin-eosin stain. Chondrocytes were observed in all 3 cases, suggesting the chondrocytes may have played a role in calcification in these three cases. To date, 62 cases of CLF (including the present cases) have been reported, and analysis of calcium compound has been performed for 29 of them. Of these 29, 15 were analyzed as calcium phosphate compounds, 9 as CPPD and 4 cases as mixed crystals like Case 3. However the analysis method and result about CPPD are no problem, the analysis result of calcium phosphate compounds depends on the using methods. Calcium phosphate or undetectable compounds was identified by XRD as hydroxyapatite (HAp), and by FTIR as calcium phosphate or undetectable compound. Analysis of calcium phosphate compounds should be condacted and identified by XRD, FTIR, and Raman. We propose two possible mechanisms for the formation of the double-layer structure in Case 3: one is formation of apatite first followed by deposition of CPPD outside, and the other is formation of CPPD first followed by conversion of CPPD in the central region to apatite. What the process of formation of the double-layer was in this cases remains unclear.
Higashi
S
S
Department of Orthopaedic Surgery, Dokkyo University School of Medicine, Tochigi.
Hamada
J
J
Ono
W
W
Tamai
K
K
Saotome
K
K
D000368:Aged; D001031:Apatites / Q000032:analysis; D002114:Calcinosis / Q000378:metabolism* / Q000473:pathology*; D002131:Calcium Pyrophosphate / Q000032:analysis*; D005260:Female; D006801:Humans; D017843:Ligamentum Flavum / Q000737:chemistry; D008875:Middle Aged; D009140:Musculoskeletal Diseases / Q000378:metabolism* / Q000473:pathology*
D001031:Apatites; C030782:carboapatite; D002131:Calcium Pyrophosphate