{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,5]],"date-time":"2026-09-05T00:47:47Z","timestamp":1788569267676,"version":"build-2803163510"},"reference-count":25,"publisher":"SAGE Publications","issue":"4","license":[{"start":{"date-parts":[[2025,10,15]],"date-time":"2025-10-15T00:00:00Z","timestamp":1760486400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"},{"start":{"date-parts":[[2025,10,15]],"date-time":"2025-10-15T00:00:00Z","timestamp":1760486400000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"funder":[{"name":"Schroeder Arthritis Institutes, University Health Network and UHN foundation"}],"content-domain":{"domain":["journals.sagepub.com"],"crossmark-restriction":true},"short-container-title":["Global Spine Journal"],"published-print":{"date-parts":[[2026,5]]},"abstract":"<jats:sec>\n                    <jats:title>Study design<\/jats:title>\n                    <jats:p>Retrospective cohort study.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Objectives<\/jats:title>\n                    <jats:p>Despite several recognized risk factors, PJK remains a common postoperative occurrence in adult spinal deformity surgery. This study aims to identify a significant preoperative sagittal alignment parameter that is associated with vertebral loading at the proximal junction and can predict the likelihood of proximal junctional kyphosis (PJK).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Fifty-five consecutive patients who underwent fusion surgery from lower thoracic (T9-T11) to the pelvis were included in this retrospective study. Based on the preoperative slope of the level above the upper-instrumented vertebrae (UIV+1), patients were stratified into two groups: posterior and anterior UIV+1 slope. Patient-specific musculoskeletal (MSK) models were created from pre and immediate postoperative EOS images. Pre and postoperative radiographic parameters, and normalized vertebral loading at UIV and UIV+1 were compared.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>6\/21 (28.6%) patients with posterior UIV+1 slope developed PJK, while the incidence of PJK for anterior UIV+1 slope was 24\/34 (70.6%). Average normalized shear difference of UIV+1 in PJK and non-PJK patients was 0.19 and 0.1 for posterior slope patients, whereas for anterior slope patients, they were 0.3 and 0.18 respectively. Statistically significant associations were revealed between UIV+1 slope, shear force and risk of PJK development.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>Utilizing mathematical and musculoskeletal analyses with clinical correlation, we were able to demonstrate UIV+1 slope as a local sagittal alignment risk factor that affects shear force at UIV\/UIV+1, influencing PJK risk. Considering UIV+1 slope as a local alignment risk factor for PJK development may provide insight regarding UIV selection and alignment goals during preoperative planning.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1177\/21925682251387966","type":"journal-article","created":{"date-parts":[[2025,10,16]],"date-time":"2025-10-16T00:49:52Z","timestamp":1760575792000},"page":"1814-1823","update-policy":"https:\/\/doi.org\/10.1177\/sage-journals-update-policy","source":"Crossref","is-referenced-by-count":2,"title":["Importance of UIV+1 Slope on Shear Force and Risk of PJK Development: Mathematical and Musculoskeletal Modeling With Clinical Confirmation"],"prefix":"10.1177","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0009-0007-1055-2350","authenticated-orcid":false,"given":"Fatemeh","family":"Alavi","sequence":"first","affiliation":[{"name":"Osteoporosis and Women\u2019s Health Research, Toronto General Hospital, University Health Network (UIHN), Toronto, ON, Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8640-7076","authenticated-orcid":false,"given":"Christopher J.","family":"Nielsen","sequence":"additional","affiliation":[{"name":"University Health Network"},{"name":"(UHN)"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Raja","family":"Rampersaud","sequence":"additional","affiliation":[{"name":"University Health Network"},{"name":"(UHN)"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Angela M.","family":"Cheung","sequence":"additional","affiliation":[{"name":"Osteoporosis and Women\u2019s Health Research, Toronto General Hospital, University Health Network (UIHN), Toronto, ON, Canada"},{"name":"University Health Network"},{"name":"(UHN)"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9173-8443","authenticated-orcid":false,"given":"Stephen","family":"Lewis","sequence":"additional","affiliation":[{"name":"University Health Network"},{"name":"(UHN)"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"179","published-online":{"date-parts":[[2025,10,15]]},"reference":[{"key":"e_1_3_3_2_2","doi-asserted-by":"publisher","DOI":"10.1097\/BRS.0b013e318271319c"},{"key":"e_1_3_3_3_2","doi-asserted-by":"publisher","DOI":"10.1097\/BRS.0b013e31826d611b"},{"key":"e_1_3_3_4_2","doi-asserted-by":"publisher","DOI":"10.1097\/BRS.0000000000000627"},{"key":"e_1_3_3_5_2","doi-asserted-by":"publisher","DOI":"10.1007\/s00586-016-4534-0"},{"key":"e_1_3_3_6_2","first-page":"199","article-title":"Proximal junctional kyphosis in adult reconstructive spine surgery results from incomplete restoration of the lumbar lordosis relative to the magnitude of the thoracic kyphosis","volume":"31","author":"Mendoza-Lattes S","year":"2011","unstructured":"Mendoza-Lattes S, Ries Z, Gao Y, Weinstein SL. Proximal junctional kyphosis in adult reconstructive spine surgery results from incomplete restoration of the lumbar lordosis relative to the magnitude of the thoracic kyphosis. 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