{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,25]],"date-time":"2026-06-25T04:00:31Z","timestamp":1782360031489,"version":"3.54.5"},"reference-count":24,"publisher":"SAGE Publications","issue":"7","license":[{"start":{"date-parts":[[2022,2,28]],"date-time":"2022-02-28T00:00:00Z","timestamp":1646006400000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"funder":[{"name":"International Spine Study Group"}],"content-domain":{"domain":["journals.sagepub.com"],"crossmark-restriction":true},"short-container-title":["Global Spine Journal"],"published-print":{"date-parts":[[2023,9]]},"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>Objective<\/jats:title>\n                    <jats:p>Investigate the patterns of fused lumbar alignment in patients requiring revision surgery for proximal junctional kyphosis (PJK).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Fifty patients (67.8 yo, 76% female) with existing thoraco-lumbar fusion (T10\/12 to pelvis) and indicated for surgical correction for PJK were included. To investigate patterns of radiographic alignment prior to PJK revision, unsupervised 2-step cluster analysis was run on parameters describing the fused lumbar spine (PI-LL) to identify natural independent groups within the cohort. Clusters were compared in terms of demographics, pre-operative alignment, surgical parameters, and post-operative alignment. Associations between pre- and post-revision PJK angles were investigated using a Pearson correlation analysis.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Analysis identified 2 distinct patterns: Under-corrected (UC, n = 12, 32%) vs over-corrected (OC, n = 34, 68%) with a silhouette of .5. The comparison demonstrated similar pelvic incidence (PI) and PJK angle but significantly greater deformity for the UC vs OC group in terms of PI-LL, PI-LL offset, pelvic tilt, and sagittal vertebral axis. The surgical strategy for PJK correction did not differ between the 2 groups in terms of approach, American Society of Anesthesiologists grade, decompression, use of osteotomy, interbody fusion, or fusion length. The post-revision PJK angle significantly correlated with the amount of PJK correction within the OC group but not within the UC group.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>This study identified 2 patterns of lumbar malalignment associated with severe PJK: over vs under corrected. Despite the difference in PJK etiology, both patterns underwent the same revision strategy. Future analysis should look at the effect of correcting focal deformity alone vs correcting focal deformity and underlying malalignment simultaneously on recurrent PJK rate.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1177\/21925682211047461","type":"journal-article","created":{"date-parts":[[2022,2,28]],"date-time":"2022-02-28T05:04:25Z","timestamp":1646024665000},"page":"1737-1744","update-policy":"https:\/\/doi.org\/10.1177\/sage-journals-update-policy","source":"Crossref","is-referenced-by-count":14,"title":["Patterns of Lumbar Spine Malalignment Leading to Revision Surgery for Proximal Junctional Kyphosis: A Cluster Analysis of Over- Versus Under-Correction"],"prefix":"10.1177","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4820-1835","authenticated-orcid":false,"given":"Renaud","family":"Lafage","sequence":"first","affiliation":[{"name":"Department of Orthopedics, Hospital for Special Surgery, New York, NY, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Peter","family":"Passias","sequence":"additional","affiliation":[{"name":"Department of Orthopedics, NYU Langone Orthopedic Hospital, New York, NY, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Basel","family":"Sheikh Alshabab","sequence":"additional","affiliation":[{"name":"Department of Orthopedics, Hospital for Special Surgery, New York, NY, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shay","family":"Bess","sequence":"additional","affiliation":[{"name":"Denver International Spine Center, Presbyterian St Luke\u2019s\/Rocky Mountain Hospital for Children, Denver, CO, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0467-5534","authenticated-orcid":false,"given":"Justin S.","family":"Smith","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, University of Virginia Medical Center, Charlottesville, VA, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eric","family":"Klineberg","sequence":"additional","affiliation":[{"name":"Department of Orthopaedic Surgery, University of California Davis, Sacramento, CA, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2170-3592","authenticated-orcid":false,"given":"Han Jo","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Orthopedics, Hospital for Special Surgery, New York, NY, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jonathan","family":"Elysee","sequence":"additional","affiliation":[{"name":"Department of Orthopedics, Hospital for Special Surgery, New York, NY, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christopher","family":"Shaffrey","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Duke University Medical Center, Durham, NC, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Douglas","family":"Burton","sequence":"additional","affiliation":[{"name":"Department of Orthopaedics, University of Kansas Medical Center, Kansas City, KS, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Richard","family":"Hostin","sequence":"additional","affiliation":[{"name":"Department of Orthopaedic Surgery, Baylor Scoliosis Center, Dallas, TX, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gregory","family":"Mundis","sequence":"additional","affiliation":[{"name":"Department Of Orthopedics, Scripps Clinic, San Diego, CA, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Frank","family":"Schwab","sequence":"additional","affiliation":[{"name":"Department of Orthopedics, Hospital for Special Surgery, New York, NY, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Virginie","family":"Lafage","sequence":"additional","affiliation":[{"name":"Department of Orthopedics, Hospital for Special Surgery, New York, NY, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"name":"On behalf of the International Spine Study Group","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"179","published-online":{"date-parts":[[2022,2,28]]},"reference":[{"key":"bibr1-21925682211047461","doi-asserted-by":"publisher","DOI":"10.1097\/BRS.0b013e31817c0428"},{"key":"bibr2-21925682211047461","doi-asserted-by":"publisher","DOI":"10.1097\/BRS.0b013e3181ae2ab2"},{"key":"bibr3-21925682211047461","doi-asserted-by":"publisher","DOI":"10.1097\/BRS.0000000000000627"},{"key":"bibr4-21925682211047461","doi-asserted-by":"publisher","DOI":"10.4184\/asj.2016.10.3.593"},{"key":"bibr5-21925682211047461","doi-asserted-by":"publisher","DOI":"10.1177\/0363546508315040"},{"key":"bibr6-21925682211047461","doi-asserted-by":"publisher","DOI":"10.1097\/BRS.0b013e3181b2e17e"},{"key":"bibr7-21925682211047461","doi-asserted-by":"publisher","DOI":"10.1097\/BRS.0b013e3181c8f35d"},{"key":"bibr8-21925682211047461","first-page":"199","volume":"31","author":"Mendoza-Lattes S","year":"2011","journal-title":"Iowa Orthop J"},{"key":"bibr9-21925682211047461","doi-asserted-by":"publisher","DOI":"10.1097\/BRS.0b013e3181eeaee2"},{"key":"bibr10-21925682211047461","doi-asserted-by":"publisher","DOI":"10.1097\/BRS.0000000000000266"},{"key":"bibr11-21925682211047461","doi-asserted-by":"publisher","DOI":"10.1097\/BRS.0000000000000246"},{"key":"bibr12-21925682211047461","doi-asserted-by":"publisher","DOI":"10.1097\/BRS.0000000000002146"},{"key":"bibr13-21925682211047461","doi-asserted-by":"publisher","DOI":"10.1007\/s00586-014-3454-0"},{"key":"bibr14-21925682211047461","doi-asserted-by":"publisher","DOI":"10.1016\/j.wneu.2018.08.242"},{"key":"bibr15-21925682211047461","doi-asserted-by":"publisher","DOI":"10.3171\/2018.9.SPINE18239"},{"key":"bibr16-21925682211047461","doi-asserted-by":"publisher","DOI":"10.1097\/BRS.0000000000001171"},{"key":"bibr17-21925682211047461","doi-asserted-by":"publisher","DOI":"10.1007\/s00586-005-0927-1"},{"key":"bibr18-21925682211047461","doi-asserted-by":"publisher","DOI":"10.1097\/BRS.0000000000003233"},{"key":"bibr19-21925682211047461","doi-asserted-by":"publisher","DOI":"10.1007\/s00586-020-06620-3"},{"key":"bibr20-21925682211047461","doi-asserted-by":"publisher","DOI":"10.1097\/BRS.0b013e3182a63c29"},{"key":"bibr21-21925682211047461","doi-asserted-by":"publisher","DOI":"10.1097\/BRS.0000000000002146"},{"key":"bibr22-21925682211047461","doi-asserted-by":"publisher","DOI":"10.1016\/j.spinee.2016.07.062"},{"key":"bibr23-21925682211047461","doi-asserted-by":"publisher","DOI":"10.1038\/135128a0"},{"key":"bibr24-21925682211047461","doi-asserted-by":"publisher","DOI":"10.1097\/BRS.0000000000001664"}],"container-title":["Global Spine Journal"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1177\/21925682211047461","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.sagepub.com\/doi\/full-xml\/10.1177\/21925682211047461","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1177\/21925682211047461","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,4,29]],"date-time":"2026-04-29T07:17:50Z","timestamp":1777447070000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.sagepub.com\/doi\/10.1177\/21925682211047461"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,2,28]]},"references-count":24,"journal-issue":{"issue":"7","published-print":{"date-parts":[[2023,9]]}},"alternative-id":["10.1177\/21925682211047461"],"URL":"https:\/\/doi.org\/10.1177\/21925682211047461","relation":{},"ISSN":["2192-5682","2192-5690"],"issn-type":[{"value":"2192-5682","type":"print"},{"value":"2192-5690","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,2,28]]}}}