Three-dimensional analysis of intervertebral range of motion in ossification of the posterior longitudinal ligament of the cervical spine

骨化明显为连续性骨化，分为2种类型：1)桥接，桥接椎间节段的前或后纵韧带厚且连续骨化，前屈曲时ROM为0.3°，旋转时ROM为0.2°；2)非桥接，骨化本身或骨化与椎体之间有微小间隙，前屈曲时ROM为4.9°，旋转时ROM为4.0°。这些发现表明，大多数使用传统放射学分类系统分类的连续型骨化具有活动节段。CT扫描上桥接和非桥接的区别可以作为动态因素的有用预测指标。

Ossifications, which were obviously of the continuous type, were divided into 2 types: 1) bridging with thick, continuous ossification of the anterior or posterior longitudinal ligament bridging intervertebral segments and with an ROM of 0.3° in AP flexion and 0.2° in rotation; and 2) nonbridging with a minute gap in the ossification itself or between the ossification and vertebra and with an ROM of 4.9° in AP flexion and 4.0° in rotation. These findings indicate that most continuous-type ossifications that are categorized using the conventional radiographic classification system have mobile segments. The discrimination between bridging and nonbridging on CT scans can be a useful predictive index for dynamic factors.