Does ossification of the posterior longitudinal ligament progress after laminoplasty? Radiographic and clinical evidence of ossification of the posterior longitudinal ligament lesion growth and the risk factors for late neurologic deterioration.

Ossification of the posterior longitudinal ligament (OPLL) is a disease process characterized by progressive growth and calcification resulting in spinal canal compromise and serious neurological sequelae in advanced cases. Historically, OPLL has most commonly been treated with posterior surgical decompression. Although this procedure indirectly decompresses the spinal cord, it does not address the offending pathological entity, and further growth of the lesion may result in delayed neurological deterioration. This fact is particularly relevant because a number of long-term studies have revealed both longitudinal and transverse disease progression in individuals treated both surgically and conservatively. Despite these high rates of radiographically documented progression, however, the rate of neurological decline in patients undergoing posterior surgery with laminoplasty is low. In this article, the authors review the pathophysiology of OPLL, evidence of disease progression, and outcome data addressing conservative and surgical treatments.