Object. Ossification of the posterior longitudinal ligament (OPLL) may produce quadriplegia. The course of future neurological deterioration in patients with radiographic evidence of OPLL, however, is not known. The authors conducted a long-term follow-up cohort study of more than 10 years to clarify the clinical course of this disease progression.
Methods. A total of 450 patients, including 304 managed conservatively and 146 treated by surgery, were enrolled in the study. All patients underwent neurological and radiographical follow-up examinations for a mean of 17.6 years. Myelopathy was graded using Nurick classification and the Japanese Orthopaedic Association scale.
Fifty-five (17%) of 323 patients without myelopathy evident at the first examination developed myelopathy during the follow-up period. Risk factors associated with the evolution of myelopathy included greater than 60% OPLL-induced stenotic compromise of the cervical canal, and increased range of motion of the cervical spine. Using Kaplan—Meier analysis, the myelopathy-free rate in patients without first-visit myelopathy was 71% after 30 years. A significant difference in final functional outcome was not observed between nonsurgical and surgical cases in which preoperative Nurick grades were 1 or 2. In patients with Nurick Grade 3 or 4 myelopathy, however, only 12% who underwent surgery eventually became wheelchair bound or bedridden compared with 89% of those managed conservatively. Surgery proved ineffective in the management of patients with Grade 5 disease.
Conclusions. Results of this long-term cohort study elucidated the clinical course of OPLL following conservative or surgical management. Surgery proved effective for the management of patients with Nurick Grades 3 and 4 myelopathy.
EpsteinNE: Ossification of the posterior longitudinal ligament in evolution in 12 patients.Spine19:673–6811994Epstein NE: Ossification of the posterior longitudinal ligament in evolution in 12 patients. Spine 19:
MatsunagaSSakouT: Epidemiology of ossification of the posterior longitudinal ligamentYonenobuKSakouTOnoK (eds): OPLL: Ossification of the Posterior Longitudinal Ligament.Tokyo: Springer-Verlag19973–17OPLL: Ossification of the Posterior Longitudinal Ligament.
NurickS: The pathogenesis of the spinal cord disorder associated with cervical spondylosis.Brain95:87–1001972Nurick S: The pathogenesis of the spinal cord disorder associated with cervical spondylosis. Brain 95:
ResnickDGuerraJJrRobinsonCAet al: Association of diffuse idiopathic skeletal hyperostosis (DISH) and calcification and ossification of the posterior longitudinal ligament.AJR Am J Roentgenol131:1049–10531978AJR Am J Roentgenol 131: