[The clinical causes of the thoracic ossification of ligamentum flavum].

OBJECTIVE: To assess the different causes of thoracic ossification of the ligamentum flavum (TOLF). METHODS: From July 1989 to November 2005, 142 cases were diagnosed the TOLF, in which 121 were operated. The lesions were classified into three types on the basis of the clinical result: (1) In such primary group (Group 1, 90 cases), without incorporation disease and Ca, P and AKP was all normal; (2) In systemic ossified TOLF group (Group 2, 30 cases), 6 cases ankylosing spondylitis, 3 cases DISH, 10 cases fluorosis, 11 cases OPLL; (3) In local spine disease group (Group 3, 22 cases), 5 cases fracture in spine, 4 cases spine TB, 13 cases posterior marginal intraosseous cartilaginous node. Such clinical feature was analysed, moreover surveyed the thoracic kyphosis angle, upper thoracic kyphosis angle, lower thoracic kyphosis angle and the vertebra body wedge change. The effect was assessed using Epstein Scale. RESULTS: (1) In Group 1, the mainly type was connected type (67/90, 74%). The ossified ligamentum flavum was mainly located at the lower thoracic and thoracic-lumber levels. The local type was less. In Group 2, the mainly type was connected type (21/30, 70%). The local type was none. The lesions figure was the most. In Group 3, the local type was the most (18/22, 82%). (2) In Group 1, the ossified ligamentum flavum was mainly located at the upper and lower thoracic levels (225/486, 47%). In Group 2, mainly located at the whole thoracic, some include cervix and lumber. In Group 3, mainly location was related with the location of primary disease. (3) In group 1, the curve was normal in 81% (73/90) of cases. In Group 2, the curve was abnormal in 87% (26/30) of cases. In Group 3, the curve was normal in the 82% (18/22) of cases. CONCLUSIONS: The TOLF relates with systemic ossify disease, the change of load on the spine, aging and so on. It should be classified according to its causes.

[The research of bone morphogenetic protein expression, CT value and mature degree of ossification in the thoracic ossification of ligamentum flavum].

OBJECTIVE: To investigate the correlation of pathology, bone morphogentic protein (BMP) expression, CT value with the ossification of thoracic ligamentum flavum (TOLF) to afford the evidence to choose appropriate treatment methods. METHODS: Twenty-three patients aged 35 - 65 years old had TOLF in my hospital as case. Their courses of disease were 2 months to 9 years. The values of blood calcium, blood phosphorus and AKP in them were normal. The 5 peoples aged 21 - 35 years old who presented fracture of thoracic but not the ligamentum flavum ossification were selected as control. We excluded those who have DISH, ankylosing spondylitis, fluorosis and other disease related with TOLF. The lesion locus were scanned and mensurated by CT. The pathology characteristics were classified into immature ossification and mature ossification by general observation, histology examination. BMP were measured by the immunohistochemical (IHC) staining techniques. RESULTS: The CT value was significantly higher in the case group (547.2 +/- 131.4) than controlled group (137.7 +/- 10.6) (t = 6.922, P = 0.000). Further, the CT value in the mature ossification (702.9 +/- 17.7) was significantly higher than the immature (480.5 +/- 180.2) (t = 5.623, P = 0.000). In addition, BMP both expressed negative in the mature ossification and the controlled group, but positive in the immature ossification. BMP expression was significantly different between the immature ossification and the mature (chi2 = 70.000, P = 0.000). CONCLUSIONS: The CT values, pathological types and BMP expression results are similar to evaluate the ossification degrees of ligamentum flavum, and then could be indirectly judged the maturation degrees of TOLF by CT to confirm the treatment methods before operation.