3-dimensional computed tomography of ossification of the spinal ligament

Ossification of the posterior longitudinal ligament in the cervical spine was studied 3-dimensionally using computed tomography scans of 32 patients. The images produced were classified into 3 types based on the posterior configuration of the ossification: (1) plank shaped, (2) spindle shaped, or (3) rod shaped. Lesions with radiographically continuous and mixed type ossification on 3-dimensional computed tomography were plank shaped or spindle shaped. Rod shaped type lesions usually were radiographically segmented or showed some other type of ossification. The 3-dimensional computed tomography images change with the growth of ossification. Plank shaped type lesions appear to be the final result of ossification. Three-dimensional computed tomography scans of ossification of the longitudinal ligament are useful for decompressive surgery, providing valuable information regarding the site of concentration of compression of the spinal cord or nerve roots and the choice of surgical procedures.