{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,30]],"date-time":"2025-10-30T11:28:44Z","timestamp":1761823724647},"reference-count":24,"publisher":"Journal of Neurosurgery Publishing Group (JNSPG)","issue":"2","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["SPI"],"published-print":{"date-parts":[[2015,8]]},"abstract":"<jats:sec>\n<jats:title>OBJECT<\/jats:title>\n<jats:p>Safe and effective insertion of occipital bone screws requires morphological analysis of the occipital bone, which is poorly documented in the literature. The authors of this study present morphological data for determining the area of screw placement for optimal internal fixation.<\/jats:p><\/jats:sec>\n<jats:sec>\n<jats:title>METHODS<\/jats:title>\n<jats:p>The subjects of this institutional review board-approved retrospective study were 105 individuals without head and neck disease who underwent CT imaging at the authors\u2019 hospital. There were 55 males and 50 females, with a mean age of 57.1 years (range 20\u201391 years). Measurements using CT were taken according to a matrix of 55 points following a grid with 1-cm spacing based on the external occipital protuberance (EOP).<\/jats:p><\/jats:sec>\n<jats:sec>\n<jats:title>RESULTS<\/jats:title>\n<jats:p>The maximum thickness of the occipital bone was at the level of the EOP at 16.4 mm. Areas with thicknesses &gt; 8 mm were more frequent at the EOP and up to 2 cm in all directions, as well as up to 1 cm in all directions at a height of 1 cm inferiorly, and up to 3 cm from the EOP inferiorly. The male group tended to have a thicker occipital bone than the female group, and the differences were significant around the EOP. The ratio of the trabecular bone to the occipital bone thickness was &gt; 30% in the central region. At positions more than 2 cm laterally, the ratio was &lt; 15%, and the ratio gradually decreased further laterally.<\/jats:p><\/jats:sec>\n<jats:sec>\n<jats:title>CONCLUSIONS<\/jats:title>\n<jats:p>Screws that are 8 mm long can be placed in the area extending 2 cm laterally from the EOP at the level of the superior nuchal line and approximately 3 cm inferior to the center. These results suggest that it may be possible to effectively insert a screw over a wider area than the conventional reference range.<\/jats:p><\/jats:sec>","DOI":"10.3171\/2014.11.spine14624","type":"journal-article","created":{"date-parts":[[2015,5,15]],"date-time":"2015-05-15T14:35:22Z","timestamp":1431700522000},"page":"254-258","source":"Crossref","is-referenced-by-count":9,"title":["Mapping occipital bone thickness using computed tomography for safe screw placement"],"prefix":"10.3171","volume":"23","author":[{"given":"Tomonori","family":"Morita","sequence":"first","affiliation":[{"name":"Departments of Orthopedic Surgery and"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tsuneo","family":"Takebayashi","sequence":"additional","affiliation":[{"name":"Departments of Orthopedic Surgery and"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hiroyuki","family":"Takashima","sequence":"additional","affiliation":[{"name":"Departments of Orthopedic Surgery and"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mitsunori","family":"Yoshimoto","sequence":"additional","affiliation":[{"name":"Departments of Orthopedic Surgery and"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kazunori","family":"Ida","sequence":"additional","affiliation":[{"name":"Departments of Orthopedic Surgery and"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Katsumasa","family":"Tanimoto","sequence":"additional","affiliation":[{"name":"Departments of Orthopedic Surgery and"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hirofumi","family":"Ohnishi","sequence":"additional","affiliation":[{"name":"Public Health, Sapporo Medical University School of Medicine, Sapporo, Hokkaido; and"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hiroyoshi","family":"Fujiwara","sequence":"additional","affiliation":[{"name":"Department of Orthopedic Surgery, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Masateru","family":"Nagae","sequence":"additional","affiliation":[{"name":"Department of Orthopedic Surgery, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Toshihiko","family":"Yamashita","sequence":"additional","affiliation":[{"name":"Departments of Orthopedic Surgery and"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1754","reference":[{"key":"b1-spine14624","series-title":"Spine (Phila Pa 1976)","doi-asserted-by":"publisher","first-page":"1425","DOI":"10.1097\/00007632-199907150-00007","article-title":"Posterior occipitocervical reconstruction using cervical pedicle screws and plate-rod systems","volume":"24","author":"Abumi","year":"1999"},{"key":"b2-spine14624","series-title":"Spine (Phila Pa 1976)","doi-asserted-by":"publisher","first-page":"530","DOI":"10.1097\/01.brs.0000154715.88911.ea","article-title":"Occipitocervical fixation: long-term results","volume":"30","author":"Deutsch","year":"2005"},{"key":"b3-spine14624","series-title":"Spine (Phila Pa 1976)","doi-asserted-by":"publisher","first-page":"1725","DOI":"10.1097\/00007632-199608010-00002","article-title":"An anatomic study of the thickness of the occipital bone. 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