Cervical ossified posterior longitudinal ligament: Etiology and surgical perspectives

The risk factors for developing myelopathy are its occurrence at a younger age, an increased cervical range of motion, the presence of a continuous or mixed type of OPLL, an OPLL occupancy ratio 30-60%, the space available for the cord of 6 to 9 mm, and OPLL fragments that are more laterally deviated as visible on an axial CT image. Modifications in the anterior approach like the “anterior floating method,” (that is, leaving a thin shell of the drilled posterior cortical shell of the OPLL floating on the anterior surface of the dura in case it is not separable from the dura) and an oblique corpectomy (drilling the vertebral body in an oblique trajectory to access the posterior osteophytic bar with OPLL to preserve the anterior vertebral body segment and cervical spinal stability)[12] try to offset the complications associated with the anterior approach. The ‘anterior floating method' obviates neurological deterioration in case the OPLL is causing significant cord compression and cannot be separated from the anterior dura; an oblique corpectomy prevents the occurrence of spinal instability due to the performance of corpectomy that includes the drilling of both anterior and posterior parts of the vertebral body from an oblique angulation, and therefore, obviates the need for a bone graft.