{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,22]],"date-time":"2026-04-22T01:58:27Z","timestamp":1776823107695,"version":"3.51.2"},"reference-count":14,"publisher":"Journal of Neurosurgery Publishing Group (JNSPG)","issue":"2","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["SPI"],"published-print":{"date-parts":[[2009,2]]},"abstract":"<jats:sec>\n<jats:title>Object<\/jats:title>\n<jats:p>The authors assessed the clinical course in patients with a narrowed cervical spinal canal caused by ossification of the posterior longitudinal ligament (OPLL), but who have no or only mild myelopathy. Additionally, the authors analyzed the factors contributing to the development and aggravation of myelopathy in patients with OPLLinduced spinal canal stenosis.<\/jats:p><\/jats:sec>\n<jats:sec>\n<jats:title>Methods<\/jats:title>\n<jats:p>Between 1997 and 2004, the authors selected treatments for patients with cervical OPLL in whom the residual space available for the spinal cord was \u2264 12 mm. Treatment decisions were based on the severity of myelopathy at presentation. Twenty-one patients with no or mild myelopathy (defined as a Japanese Orthopaedic Association [JOA] scale score \u2265 14 points) received conservative treatment, with a mean follow-up period of 4.5 years. In 20 patients with moderate or severe myelopathy (JOA scale score &lt; 14 points), the authors performed surgery via an anterior approach. The clinical course in these patients was assessed with the JOA scale and the OPLL types were classified. The authors evaluated the range of motion between C-1 and C-7, the developmental segmental sagittal diameter, the percentage of spinal canal diameter occupied by the OPLL (% ratio), and the residual space available for the spinal cord on cervical radiographs; T2-weighted MR images were examined for high signal changes (HSCs).<\/jats:p><\/jats:sec>\n<jats:sec>\n<jats:title>Results<\/jats:title>\n<jats:p>In the conservative treatment group, 8 patients showed improvement, 12 remained unchanged, and 1 patient's condition became slightly worse during the observation period. Fifteen patients in this group had mixedtype, 3 had continuous-type, 2 had localized-type, and 1 had a segmental-type OPLL. In the surgically treated group, there were 12 patients with segmental-type, 10 patients with mixed-type, and 1 with localized-type OPLL. The mean range of motion at C1\u20137 was 36.4\u00b0 in the conservatively treated group and 46.5\u00b0 in the surgical group (p &lt; 0.05). No significant difference was seen between the groups in terms of developmental segmental sagittal diameter, % ratio, or residual space available for the cord. No HSCs were noted in the conservative group, while 17 patients in the surgical group had HSCs (p &lt; 0.05).<\/jats:p><\/jats:sec>\n<jats:sec>\n<jats:title>Conclusions<\/jats:title>\n<jats:p>In the present study, the authors demonstrate that the mobility of the cervical spine and the type of OPLL are important factors contributing to the development and aggravation of myelopathy in patients with OPLLinduced spinal canal stenosis. The authors advocate conservative treatment in most patients with OPLLs who have no or only mild myelopathy, even in the presence of spinal canal narrowing.<\/jats:p><\/jats:sec>","DOI":"10.3171\/2008.10.spi08480","type":"journal-article","created":{"date-parts":[[2011,2,23]],"date-time":"2011-02-23T21:39:08Z","timestamp":1298497148000},"page":"122-128","source":"Crossref","is-referenced-by-count":44,"title":["Cervical myelopathy in patients with ossification of the posterior longitudinal ligament"],"prefix":"10.3171","volume":"10","author":[{"given":"Macondo","family":"Mochizuki","sequence":"first","affiliation":[{"name":"Department of Orthopaedic Surgery, Numazu City Hospital, Shizuoka; and"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Atsuomi","family":"Aiba","sequence":"additional","affiliation":[{"name":"Department of Orthopaedic Surgery, Numazu City Hospital, Shizuoka; and"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mitsuhiro","family":"Hashimoto","sequence":"additional","affiliation":[{"name":"Department of Orthopaedic Surgery, Numazu City Hospital, Shizuoka; and"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Takayuki","family":"Fujiyoshi","sequence":"additional","affiliation":[{"name":"Spine Section, Department of Orthopaedic Surgery, Chiba University Graduate School of Medicine, Chiba, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Masashi","family":"Yamazaki","sequence":"additional","affiliation":[{"name":"Spine Section, Department of Orthopaedic Surgery, Chiba University Graduate School of Medicine, Chiba, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1754","reference":[{"key":"b1-0100122","series-title":"Radiology","doi-asserted-by":"publisher","first-page":"789","DOI":"10.1148\/radiol.2213010365","article-title":"Intramedullary high signal intensity on 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