THE SIGNIFICANCE OF THE CERVICAL SOFT DISC HERNIATION IN THE OSSIFICATION OF THE POSTERIOR LONGITUDINAL LIGAMENT

The significance and role of cervical soft disc hernia in ossification of the posterior longitudinal ligament were investigated based on 54 surgical cases. The types of ossification of the posterior longitudina l ligament were divided into three sub-types: segmental, continuous, a nd mixed types. In the current series, there were 29 segmental type, 1 2 continuous type, and 13 mixed type. In the 29 segmental type, 23 pat ients had accompanying cervical disc hernias (79%). In the 12 continuo us type, only 2 patients (17%), and in the 13 mixed type, 5 patients ( 33%), had accompanying disc hernias. According to the current study, a n essential difference exists between the segmental type and the conti nuous or mixed types. In addition, the current result seems to indicat e that, at least in the segmental type, disc herniation is not the pro moting or initiating factor of ossification of the posterior longitudi nal ligament, but that, in these cases, the fragility of the posterior longitudinal ligament may increase the chance of a disc hernia.