{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,26]],"date-time":"2026-08-26T22:41:03Z","timestamp":1787784063484,"version":"build-2784847793"},"reference-count":18,"publisher":"Journal of Neurosurgery Publishing Group (JNSPG)","issue":"3","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2004,3]]},"abstract":"<jats:p content-type=\"fine-print\"><jats:italic>Object.<\/jats:italic> 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.<\/jats:p>\n<jats:p content-type=\"fine-print\"><jats:italic>Methods.<\/jats:italic> 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.<\/jats:p>\n<jats:p content-type=\"fine-print\">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\u2014Meier 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.<\/jats:p>\n<jats:p content-type=\"fine-print\"><jats:italic>Conclusions.<\/jats:italic> 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.<\/jats:p>","DOI":"10.3171\/spi.2004.100.3.0245","type":"journal-article","created":{"date-parts":[[2009,5,7]],"date-time":"2009-05-07T16:00:01Z","timestamp":1241712001000},"page":"245-248","source":"Crossref","is-referenced-by-count":50,"title":["Clinical course of patients with ossification of the posterior longitudinal ligament: a minimum 10-year cohort study"],"prefix":"10.3171","volume":"100","author":[{"given":"Shunji","family":"Matsunaga","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Takashi","family":"Sakou","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eiji","family":"Taketomi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Setsuro","family":"Komiya","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1754","reference":[{"key":"b1","series-title":"Spine","doi-asserted-by":"publisher","first-page":"673","DOI":"10.1097\/00007632-199403001-00006","article-title":"Ossification of the posterior longitudinal ligament in evolution in 12 patients.","volume":"19","author":"Epstein","year":"1994"},{"key":"b2","series-title":"Spine","doi-asserted-by":"publisher","first-page":"2247","DOI":"10.1097\/00007632-199510001-00012","article-title":"Long-term follow-up evaluation of surgery for ossification of the posterior longitudinal ligament.","volume":"20","author":"Goto","year":"1995"},{"key":"b3","series-title":"J Am Stat Assoc","doi-asserted-by":"publisher","first-page":"457","DOI":"10.1080\/01621459.1958.10501452","article-title":"Nonparametric estimation from incomplete observations.","volume":"53","author":"Kaplan","year":"1958"},{"key":"b4","series-title":"Guy Hospital Report","first-page":"17","article-title":"On paraplegia depending on the ligament of the spine.","volume":"3","author":"Key","year":"1838"},{"key":"b5","series-title":"Neurosurgery","doi-asserted-by":"publisher","first-page":"212","DOI":"10.1227\/00006123-198608000-00006","article-title":"Ossification of the posterior longitudinal ligament in Caucasians: diagnosis and surgical intervention.","volume":"19","author":"Klara","year":"1986"},{"key":"b6","series-title":"Can J Neurol Sci","doi-asserted-by":"publisher","first-page":"329","DOI":"10.1017\/S0317167100048265","article-title":"Cervical myelopathy secondary to ossification of the posterior longitudinal ligament in a Caucasian patient.","volume":"20","author":"Maroun","year":"1993"},{"key":"b7","series-title":"OPLL: Ossification of the Posterior Longitudinal Ligament.","first-page":"3","article-title":"Epidemiology of ossification of the posterior longitudinal ligament","author":"Matsunaga","year":"1997"},{"key":"b8","series-title":"J Bone Joint Surg Br","first-page":"569","article-title":"Cervical cord compression from ossification of the posterior longitudinal ligament in non-orientals.","volume":"69","author":"McAfee","year":"1987"},{"key":"b9","series-title":"Am J Roentgenol Radium Ther Nucl Med","doi-asserted-by":"publisher","first-page":"365","DOI":"10.2214\/ajr.105.2.365","article-title":"Calcification of the posterior longitudinal ligament: a cause of cervical myelopathy.","volume":"105","author":"Minagi","year":"1969"},{"key":"b10","series-title":"Spine","doi-asserted-by":"publisher","first-page":"531","DOI":"10.1097\/00007632-198607000-00005","article-title":"Extensive simultaneous multisegment laminectomy for myelopathy due to the ossification of the posterior longitudinal ligament in the cervical region.","volume":"11","author":"Miyazaki","year":"1986"},{"key":"b11","series-title":"Brain","doi-asserted-by":"publisher","first-page":"87","DOI":"10.1093\/brain\/95.1.87","article-title":"The pathogenesis of the spinal cord disorder associated with cervical spondylosis.","volume":"95","author":"Nurick","year":"1972"},{"key":"b12","series-title":"Spine","doi-asserted-by":"publisher","first-page":"2024","DOI":"10.1097\/00007632-199310001-00016","article-title":"Magnetic resonance imaging study on the results of surgery for cervical compression myelopathy.","volume":"18","author":"Okada","year":"1993"},{"key":"b13","series-title":"Spine","doi-asserted-by":"publisher","first-page":"126","DOI":"10.1097\/00007632-197706000-00005","article-title":"Ossified posterior longitudinal ligament. 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