[Roentgenological and quantitative microradiographic study on ossification of posterior longitudinal ligament].

The purpose of this study was to reveal whether patients with OPLL had increased tendency of ossification in other tissues as well. Firstly patients with OPLL were classified according to radiological characteristics of ossification. Secondly transilial bone biopsy to iliac bone followed by Jowsey's microradiological analysis was performed in each patient with OPLL, patients with osteoporosis and normal individuals. The result is summarized as follows: OPLL is classified radiologically into three groups. Patients with OPLL tend to have ossification of other organs. The trabecular bone area in OPLL is significantly higher than normal and osteoporotic group. The resting surface of OPLL group is lower than normal and the turnover in OPLL is higher than normal group. The bone mineral content is more increased in OPLL group.