[Updates on ossification of posterior longitudinal ligament. Clinical results and problems of posterior decompression for OPLL of the cervical spine].

Clinical results of expansive laminoplasty (ELAP) for ossification of the posterior longitudinal ligament (OPLL) of the cervical spine are satisfactory and are preserved for long period. ELAP is also thought to be easier and safer procedure than anterior fusion for OPLL of the cervical spine. However, appropriate decompression can not be achieved by ELAP without sufficient dorsal shift of the spinal cord, because pathological lesion exists ventral to the spinal cord in patients with OPLL. Kyphotic alignment, high OPLL occupying ratio, hill-shaped ossification are considered to be risk factors contributing to inappropriate decompression. To acquire satisfactory operative results, careful consideration for the indication of ELAP should be necessary for each patient.