{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,29]],"date-time":"2026-09-29T07:02:15Z","timestamp":1790665335459,"version":"4.1.0"},"reference-count":13,"publisher":"SAGE Publications","issue":"7","license":[{"start":{"date-parts":[[2026,4,13]],"date-time":"2026-04-13T00:00:00Z","timestamp":1776038400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,4,13]],"date-time":"2026-04-13T00:00:00Z","timestamp":1776038400000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"content-domain":{"domain":["journals.sagepub.com"],"crossmark-restriction":true},"short-container-title":["Global Spine Journal"],"published-print":{"date-parts":[[2026,9]]},"abstract":"<jats:sec>\n                    <jats:title>Study Design<\/jats:title>\n                    <jats:p>Cadaveric biomechanical analysis.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Objectives<\/jats:title>\n                    <jats:p>The specific vertebral region that contributes most critically to pedicle screw fixation remains controversial. This study evaluates screw anchorage under cyclic fatigue loading to determine how bone quality affects the relative contributions of the pedicle and vertebral body to stability.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>\n                      Twelve human lumbar vertebrae (L1\u2013L4) from donors aged 71.3 \u00b1 14.2\u00a0years were selected, including six with normal bone density (&gt;120\u00a0mg\/cm\n                      <jats:sup>3<\/jats:sup>\n                      ) and six osteoporotic (&lt;80\u00a0mg\/cm\n                      <jats:sup>3<\/jats:sup>\n                      ). Each vertebra was bilaterally instrumented with the largest self-tapping polyaxial screws fitting the inner cortical diameter. One pedicle received a 35\u00a0mm screw, and the contralateral pedicle received the longest screw without cortical breach. Screw side and specimen order were randomized. Sinusoidal cranial-caudal loading at 0.5\u00a0Hz was applied, starting at 100\u00a0N and increasing by 1\u00a0\n                      <jats:italic toggle=\"yes\">N<\/jats:italic>\n                      per cycle, until 5.4\u00a0mm screw head displacement (\u223c20\u00b0) was reached.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      In healthy vertebrae, mean fatigue loads were similar for short (315.6 \u00b1 148.7\u00a0\n                      <jats:italic toggle=\"yes\">N<\/jats:italic>\n                      ) and long screws (309.0 \u00b1 138.3\u00a0\n                      <jats:italic toggle=\"yes\">N<\/jats:italic>\n                      ). In osteoporotic bone, long screws (230.9 \u00b1 55.0\u00a0\n                      <jats:italic toggle=\"yes\">N<\/jats:italic>\n                      ) showed significantly greater fatigue resistance than short screws (175.1 \u00b1 45.5\u00a0\n                      <jats:italic toggle=\"yes\">N<\/jats:italic>\n                      ;\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      = .045). Short screws in osteoporotic vertebrae also failed after fewer cycles than long screws in osteoporotic vertebrae (\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      = .047) and short screws in healthy bone vertebrae (\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      = .049).\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>In healthy vertebrae, screw anchorage is mainly pedicular, and extending screw length into the vertebral body adds no benefit. In osteoporotic bone, overall fixation strength declines, but vertebral body contribution increases, so longer screws provide significantly greater stability, whereas shorter screws remain adequate in healthy bone.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1177\/21925682261442309","type":"journal-article","created":{"date-parts":[[2026,4,13]],"date-time":"2026-04-13T22:42:57Z","timestamp":1776120177000},"page":"3335-3342","update-policy":"https:\/\/doi.org\/10.1177\/sage-journals-update-policy","source":"Crossref","is-referenced-by-count":2,"title":["Influence of Screw Length and Bone Quality on Pedicle Screw Anchorage Under Cyclic Fatigue Loading"],"prefix":"10.1177","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0009-0004-7146-7879","authenticated-orcid":false,"given":"Friederike Eva","family":"Roch","sequence":"first","affiliation":[{"name":"University of G\u00f6ttingen"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bet\u00fcl","family":"Tekin","sequence":"additional","affiliation":[{"name":"University of G\u00f6ttingen"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3086-4278","authenticated-orcid":false,"given":"Katharina","family":"J\u00e4ckle","sequence":"additional","affiliation":[{"name":"University of G\u00f6ttingen"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marc-Pascal","family":"Meier","sequence":"additional","affiliation":[{"name":"University of G\u00f6ttingen"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Friederike","family":"Klockner","sequence":"additional","affiliation":[{"name":"University of G\u00f6ttingen"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hassan","family":"Awan Malik","sequence":"additional","affiliation":[{"name":"University of G\u00f6ttingen"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wolfgang","family":"Lehmann","sequence":"additional","affiliation":[{"name":"University of G\u00f6ttingen"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9812-4658","authenticated-orcid":false,"given":"Lukas","family":"Weiser","sequence":"additional","affiliation":[{"name":"University of G\u00f6ttingen"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4357-4886","authenticated-orcid":false,"given":"Paul Jonathan","family":"Roch","sequence":"additional","affiliation":[{"name":"University of G\u00f6ttingen"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"179","published-online":{"date-parts":[[2026,4,13]]},"reference":[{"key":"e_1_3_5_2_2","first-page":"9","volume-title":"Lumbar Spine Online Textbook","author":"Defino H","year":"2025","unstructured":"Defino H, Galbusera F, Wilke HJ. 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