{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,31]],"date-time":"2026-10-31T23:25:40Z","timestamp":1793489140237,"version":"4.5.0"},"reference-count":25,"publisher":"Journal of Neurosurgery Publishing Group (JNSPG)","issue":"3","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2020,3]]},"abstract":"<jats:sec><jats:title>OBJECTIVE<\/jats:title><jats:p>Cervical deformity (CD) is difficult to define due to the high variability in normal cervical alignment based on postural- and thoracolumbar-driven changes to cervical alignment. The purpose of this study was to identify whether patterns of sagittal deformity could be established based on neutral and dynamic alignment, as shown on radiographs.<\/jats:p><\/jats:sec><jats:sec><jats:title>METHODS<\/jats:title><jats:p>This study is a retrospective review of a prospective, multicenter database of CD patients who underwent surgery from 2013 to 2015. Their radiographs were reviewed by 12 individuals using a consensus-based method to identify severe sagittal CD. Radiographic parameters correlating with health-related quality of life were introduced in a two-step cluster analysis (a combination of hierarchical cluster and k-means cluster) to identify patterns of sagittal deformity. A comparison of lateral and lateral extension radiographs between clusters was performed using an ANOVA in a post hoc analysis.<\/jats:p><\/jats:sec><jats:sec><jats:title>RESULTS<\/jats:title><jats:p>Overall, 75 patients were identified as having severe CD due to sagittal malalignment, and they formed the basis of this study. Their mean age was 64 years, their body mass index was 29 kg\/m<jats:sup>2<\/jats:sup>, and 66% were female. There were significant correlations between focal alignment\/flexibility of maximum kyphosis, cervical lordosis, and thoracic slope minus cervical lordosis (TS-CL) flexibility (r = 0.27, 0.31, and \u22120.36, respectively). Cluster analysis revealed 3 distinct groups based on alignment and flexibility. Group 1 (a pattern involving a flat neck with lack of compensation) had a large TS-CL mismatch despite flexibility in cervical lordosis; group 2 (a pattern involving focal deformity) had focal kyphosis between 2 adjacent levels but no large regional cervical kyphosis under the setting of a low T1 slope (T1S); and group 3 (a pattern involving a cervicothoracic deformity) had a very large T1S with a compensatory hyperlordosis of the cervical spine.<\/jats:p><\/jats:sec><jats:sec><jats:title>CONCLUSIONS<\/jats:title><jats:p>Three distinct patterns of CD were identified in this cohort: flat neck, focal deformity, and cervicothoracic deformity. One key element to understanding the difference between these groups was the alignment seen on extension radiographs. This information is a first step in developing a classification system that can guide the surgical treatment for CD and the choice of fusion level.<\/jats:p><\/jats:sec>","DOI":"10.3171\/2019.9.spine19730","type":"journal-article","created":{"date-parts":[[2019,11,15]],"date-time":"2019-11-15T23:10:54Z","timestamp":1573859454000},"page":"353-359","source":"Crossref","is-referenced-by-count":33,"title":["The morphology of cervical deformities: a two-step cluster analysis to identify cervical deformity patterns"],"prefix":"10.3171","volume":"32","author":[{"given":"Han Jo","family":"Kim","sequence":"first","affiliation":[{"name":"Department of Orthopedics, Hospital for Special Surgery, New York;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sohrab","family":"Virk","sequence":"additional","affiliation":[{"name":"Department of Orthopedics, Hospital for Special Surgery, New York;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jonathan","family":"Elysee","sequence":"additional","affiliation":[{"name":"Department of Orthopedics, Hospital for Special Surgery, New York;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Peter","family":"Passias","sequence":"additional","affiliation":[{"name":"Department of Orthopedics, NYU Langone Orthopedic Hospital, New York, New York;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christopher","family":"Ames","sequence":"additional","affiliation":[{"name":"Department of Neurological Surgery, UCSF School of Medicine, San Francisco, California;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christopher I.","family":"Shaffrey","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Duke University Medical Center, Durham, North Carolina;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gregory","family":"Mundis","sequence":"additional","affiliation":[{"name":"San Diego Center for Spinal Disorders, La Jolla, California;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Themistocles","family":"Protopsaltis","sequence":"additional","affiliation":[{"name":"Department of Orthopedics, NYU Langone Orthopedic Hospital, New York, New York;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Munish","family":"Gupta","sequence":"additional","affiliation":[{"name":"Department of Orthopaedic Surgery, Washington University, St. Louis, Missouri;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eric","family":"Klineberg","sequence":"additional","affiliation":[{"name":"Department of Orthopaedic Surgery, UC Davis Health, Sacramento, California;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Justin S.","family":"Smith","sequence":"additional","affiliation":[{"name":"Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia; and"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Douglas","family":"Burton","sequence":"additional","affiliation":[{"name":"Department of Orthopedic Surgery, University of Kansas Medical Center, Kansas City, Kansas"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Frank","family":"Schwab","sequence":"additional","affiliation":[{"name":"Department of Orthopedics, Hospital for Special Surgery, New York;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Virginie","family":"Lafage","sequence":"additional","affiliation":[{"name":"Department of Orthopedics, Hospital for Special Surgery, New York;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Renaud","family":"Lafage","sequence":"additional","affiliation":[{"name":"Department of Orthopedics, Hospital for Special Surgery, New York;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"_","family":"_","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1754","reference":[{"issue":"22 Suppl 1","key":"b1","series-title":"Spine (Phila Pa 1976)","doi-asserted-by":"publisher","first-page":"S149","DOI":"10.1097\/BRS.0b013e3182a7f449","article-title":"Cervical radiographical alignment: comprehensive assessment techniques and potential importance in cervical myelopathy","volume":"38","author":"Ames CP","year":"2013","unstructured":"Ames CP, Blondel B, Scheer JK, Schwab FJ, Le Huec JC, Massicotte EM, : Cervical radiographical alignment: comprehensive assessment techniques and potential importance in cervical myelopathy. Spine (Phila Pa 1976) 38 (22 Suppl 1):S149\u2013S160, 201310.1097\/BRS.0b013e3182a7f449"},{"key":"b2","series-title":"J Neurosurg Spine","doi-asserted-by":"publisher","first-page":"673","DOI":"10.3171\/2014.12.SPINE14780","article-title":"Reliability assessment of a novel cervical spine deformity classification system","volume":"23","author":"Ames CP","year":"2015","unstructured":"Ames CP, Smith JS, Eastlack R, Blaskiewicz DJ, Shaffrey CI, Schwab F, : Reliability assessment of a novel cervical spine deformity classification system. J Neurosurg Spine 23:673\u2013683, 201510.3171\/2014.12.SPINE1478026273762"},{"key":"b3","series-title":"J Neurosurg Spine","doi-asserted-by":"publisher","first-page":"269","DOI":"10.3171\/2013.5.SPINE121067","article-title":"A standardized nomenclature for cervical spine soft-tissue release and osteotomy for deformity correction: clinical article","volume":"19","author":"Ames CP","year":"2013","unstructured":"Ames CP, Smith JS, Scheer JK, Shaffrey CI, Lafage V, Deviren V, : A standardized nomenclature for cervical spine soft-tissue release and osteotomy for deformity correction: clinical article. J Neurosurg Spine 19:269\u2013278, 20132382928710.3171\/2013.5.SPINE121067"},{"key":"b4","series-title":"Eur Spine J","doi-asserted-by":"publisher","first-page":"982","DOI":"10.1007\/s00586-005-0927-1","article-title":"Validation of new clinical quantitative analysis software applicable in spine orthopaedic studies","volume":"15","author":"Champain S","year":"2006","unstructured":"Champain S, Benchikh K, Nogier A, Mazel C, Guise JD, Skalli W: Validation of new clinical quantitative analysis software applicable in spine orthopaedic studies. Eur Spine J 15:982\u2013991, 20061596570810.1007\/s00586-005-0927-1"},{"key":"b5","series-title":"Spine (Phila Pa 1976)","doi-asserted-by":"publisher","first-page":"1795","DOI":"10.1097\/BRS.0000000000001698","article-title":"Predicting cervical alignment required to maintain horizontal gaze based on global spinal alignment","volume":"41","author":"Diebo BG","year":"2016","unstructured":"Diebo BG, Challier V, Henry JK, Oren JH, Spiegel MA, Vira S, : Predicting cervical alignment required to maintain horizontal gaze based on global spinal alignment. Spine (Phila Pa 1976) 41:1795\u20131800, 201610.1097\/BRS.0000000000001698"},{"key":"b6","series-title":"Global Spinal Alignment: Principles, Pathologies, and Procedures","first-page":"3","article-title":"Spinal alignment versus spinal balance","author":"Dubousset J","year":"2015","unstructured":"Dubousset J, Challier V, Farcy JP, Schwab FJ, Lafage V: Spinal alignment versus spinal balance, in Haid RW, Shaffrey CI, Youssef JA,  (eds): Global Spinal Alignment: Principles, Pathologies, and Procedures. St. Louis: Quality Medical Publishing, 2015, pp 3\u201310"},{"key":"b7","series-title":"Global Spinal Alignment: Principles, Pathologies, and Procedures","first-page":"117","article-title":"Cervical region","author":"Fontes RT","year":"2015","unstructured":"Fontes RT: Cervical region, in Haid RW, Shaffrey CI, Youssef JA,  (eds): Global Spinal Alignment: Principles, Pathologies, and Procedures. St. Louis: Quality Medical Publishing, 2015, pp 117\u2013124"},{"key":"b8","series-title":"Spine (Phila Pa 1976)","doi-asserted-by":"publisher","first-page":"E739","DOI":"10.1097\/BRS.0b013e31817f1f8b","article-title":"Dropped head deformity due to cervical myopathy: surgical treatment outcomes and complications spanning twenty years","volume":"33","author":"Gerling MC","year":"2008","unstructured":"Gerling MC, Bohlman HH: Dropped head deformity due to cervical myopathy: surgical treatment outcomes and complications spanning twenty years. Spine (Phila Pa 1976) 33:E739\u2013E745, 200810.1097\/BRS.0b013e31817f1f8b"},{"key":"b9","series-title":"Spine (Phila Pa 1976)","doi-asserted-by":"publisher","first-page":"2024","DOI":"10.1097\/01.brs.0000179086.30449.96","article-title":"The impact of positive sagittal balance in adult spinal deformity","volume":"30","author":"Glassman SD","year":"2005","unstructured":"Glassman SD, Bridwell K, Dimar JR, Horton W, Berven S, Schwab F: The impact of positive sagittal balance in adult spinal deformity. Spine (Phila Pa 1976) 30:2024\u20132029, 200510.1097\/01.brs.0000179086.30449.96"},{"key":"b10","series-title":"Spine (Phila Pa 1976)","doi-asserted-by":"publisher","first-page":"371","DOI":"10.1097\/BRS.0000000000001221","article-title":"Impact of cervical sagittal alignment parameters on neck disability","volume":"41","author":"Iyer S","year":"2016","unstructured":"Iyer S, Nemani VM, Nguyen J, Elysee J, Burapachaisri A, Ames CP, : Impact of cervical sagittal alignment parameters on neck disability. Spine (Phila Pa 1976) 41:371\u2013377, 201610.1097\/BRS.0000000000001221"},{"key":"b11","series-title":"Neurosurgery","doi-asserted-by":"publisher","first-page":"108","DOI":"10.1227\/NEU.0000000000001193","article-title":"Natural head posture in the setting of sagittal spinal deformity: validation of chin-brow vertical angle, slope of line of sight, and McGregor\u2019s slope with health-related quality of life","volume":"79","author":"Lafage R","year":"2016","unstructured":"Lafage R, Challier V, Liabaud B, Vira S, Ferrero E, Diebo BG, : Natural head posture in the setting of sagittal spinal deformity: validation of chin-brow vertical angle, slope of line of sight, and McGregor\u2019s slope with health-related quality of life. Neurosurgery 79:108\u2013115, 201610.1227\/NEU.000000000000119326702836"},{"key":"b12","series-title":"Spine J","doi-asserted-by":"publisher","first-page":"2493","DOI":"10.1016\/j.spinee.2015.08.067","article-title":"Validation of a new computer-assisted tool to measure spino-pelvic parameters","volume":"15","author":"Lafage R","year":"2015","unstructured":"Lafage R, Ferrero E, Henry JK, Challier V, Diebo B, Liabaud B, : Validation of a new computer-assisted tool to measure spino-pelvic parameters. Spine J 15:2493\u20132502, 20152634324310.1016\/j.spinee.2015.08.067"},{"key":"b13","series-title":"Global Spinal Alignment: Principles, Pathologies, and Procedures","first-page":"124","article-title":"Cervicothoracic region","author":"Lau AA","year":"2015","unstructured":"Lau AA, Fehlings M: Cervicothoracic region, in Haid RW, Shaffrey CI, Youssef JA,  (eds): Global Spinal Alignment: Principles, Pathologies, and Procedures. St. Louis: Quality Medical Publishing, 2015, pp 124\u2013148"},{"key":"b14","series-title":"World Neurosurg","doi-asserted-by":"publisher","first-page":"e61","DOI":"10.1016\/j.wneu.2017.12.024","article-title":"Drivers of cervical deformity have a strong influence on achieving optimal radiographic and clinical outcomes at 1 year after cervical deformity surgery","volume":"112","author":"Passias PG","year":"2018","unstructured":"Passias PG, Bortz C, Horn S, Segreto F, Poorman G, Jalai C, : Drivers of cervical deformity have a strong influence on achieving optimal radiographic and clinical outcomes at 1 year after cervical deformity surgery. World Neurosurg 112:e61\u2013e68, 201810.1016\/j.wneu.2017.12.02429248781"},{"key":"b15","series-title":"Eur Spine J","doi-asserted-by":"publisher","first-page":"1111","DOI":"10.1007\/s00586-016-4653-7","article-title":"Cervical sagittal deformity develops after PJK in adult thoracolumbar deformity correction: radiographic analysis utilizing a novel global sagittal angular parameter, the CTPA","volume":"26","author":"Protopsaltis T","year":"2017","unstructured":"Protopsaltis T, Bronsard N, Soroceanu A, Henry JK, Lafage R, Smith J, : Cervical sagittal deformity develops after PJK in adult thoracolumbar deformity correction: radiographic analysis utilizing a novel global sagittal angular parameter, the CTPA. Eur Spine J 26:1111\u20131120, 20172743769010.1007\/s00586-016-4653-7"},{"key":"b16","series-title":"J Neurosurg Spine","doi-asserted-by":"publisher","first-page":"153","DOI":"10.3171\/2014.11.SPINE1441","article-title":"How the neck affects the back: changes in regional cervical sagittal alignment correlate to HRQOL improvement in adult thoracolumbar deformity patients at 2-year follow-up","volume":"23","author":"Protopsaltis TS","year":"2015","unstructured":"Protopsaltis TS, Scheer JK, Terran JS, Smith JS, Hamilton DK, Kim HJ, : How the neck affects the back: changes in regional cervical sagittal alignment correlate to HRQOL improvement in adult thoracolumbar deformity patients at 2-year follow-up. J Neurosurg Spine 23:153\u2013158, 20152597807710.3171\/2014.11.SPINE1441"},{"key":"b17","series-title":"Spine (Phila Pa 1976)","doi-asserted-by":"publisher","first-page":"2070","DOI":"10.1097\/BRS.0000000000000641","article-title":"Postoperative cervical sagittal imbalance negatively affects outcomes after surgery for cervical spondylotic myelopathy","volume":"39","author":"Roguski M","year":"2014","unstructured":"Roguski M, Benzel EC, Curran JN, Magge SN, Bisson EF, Krishnaney AA, : Postoperative cervical sagittal imbalance negatively affects outcomes after surgery for cervical spondylotic myelopathy. Spine (Phila Pa 1976) 39:2070\u20132077, 201410.1097\/BRS.0000000000000641"},{"key":"b18","series-title":"Spine (Phila Pa 1976)","doi-asserted-by":"publisher","first-page":"932","DOI":"10.1097\/BRS.0000000000000330","article-title":"Effect of cervical kyphotic deformity type on the motion characteristics and dynamic spinal cord compression","volume":"39","author":"Ruangchainikom M","year":"2014","unstructured":"Ruangchainikom M, Daubs MD, Suzuki A, Hayashi T, Weintraub G, Lee CJ, : Effect of cervical kyphotic deformity type on the motion characteristics and dynamic spinal cord compression. Spine (Phila Pa 1976) 39:932\u2013938, 201410.1097\/BRS.0000000000000330"},{"key":"b19","series-title":"J Neurosurg Spine","doi-asserted-by":"publisher","first-page":"141","DOI":"10.3171\/2013.4.SPINE12838","article-title":"Cervical spine alignment, sagittal deformity, and clinical implications: a review","volume":"19","author":"Scheer JK","year":"2013","unstructured":"Scheer JK, Tang JA, Smith JS, Acosta FL Jr, Protopsaltis TS, Blondel B, : Cervical spine alignment, sagittal deformity, and clinical implications: a review. J Neurosurg Spine 19:141\u2013159, 20132376802310.3171\/2013.4.SPINE12838"},{"key":"b20","series-title":"Spine (Phila Pa 1976)","doi-asserted-by":"publisher","first-page":"E803","DOI":"10.1097\/BRS.0b013e318292b7b9","article-title":"Radiographical spinopelvic parameters and disability in the setting of adult spinal deformity: a prospective multicenter analysis","volume":"38","author":"Schwab FJ","year":"2013","unstructured":"Schwab FJ, Blondel B, Bess S, Hostin R, Shaffrey CI, Smith JS, : Radiographical spinopelvic parameters and disability in the setting of adult spinal deformity: a prospective multicenter analysis. Spine (Phila Pa 1976) 38:E803\u2013E812, 201310.1097\/BRS.0b013e318292b7b9"},{"key":"b21","series-title":"(Phila Pa 1976)","doi-asserted-by":"publisher","first-page":"1077","DOI":"10.1097\/BRS.0b013e31823e15e2","article-title":"Scoliosis Research Society\u2014Schwab Adult Spinal Deformity Classification: a validation study","volume":"37","author":"Schwab F","year":"2012","unstructured":"Schwab F, Ungar B, Blondel B, Buchowski J, Coe J, Deinlein D, : Scoliosis Research Society\u2014Schwab Adult Spinal Deformity Classification: a validation study. Spine (Phila Pa 1976) 37:1077\u20131082, 201210.1097\/BRS.0b013e31823e15e2"},{"key":"b22","series-title":"World Neurosurg","doi-asserted-by":"publisher","first-page":"228","DOI":"10.1016\/j.wneu.2016.04.020","article-title":"Assessment of surgical treatment strategies for moderate to severe cervical spinal deformity reveals marked variation in approaches, osteotomies, and fusion levels","volume":"91","author":"Smith JS","year":"2016","unstructured":"Smith JS, Klineberg E, Shaffrey CI, Lafage V, Schwab FJ, Protopsaltis T, : Assessment of surgical treatment strategies for moderate to severe cervical spinal deformity reveals marked variation in approaches, osteotomies, and fusion levels. World Neurosurg 91:228\u2013237, 20162708626010.1016\/j.wneu.2016.04.020"},{"key":"b23","series-title":"Neurosurgery","doi-asserted-by":"publisher","first-page":"716","DOI":"10.1093\/neuros\/nyx028","article-title":"The health impact of adult cervical deformity in patients presenting for surgical treatment: comparison to United States population norms and chronic disease states based on the EuroQuol-5 Dimensions Questionnaire","volume":"80","author":"Smith JS","year":"2017","unstructured":"Smith JS, Line B, Bess S, Shaffrey CI, Kim HJ, Mundis G, : The health impact of adult cervical deformity in patients presenting for surgical treatment: comparison to United States population norms and chronic disease states based on the EuroQuol-5 Dimensions Questionnaire. Neurosurgery 80:716\u2013725, 20172836852410.1093\/neuros\/nyx028"},{"key":"b24","series-title":"Neurosurgery","doi-asserted-by":"publisher","first-page":"561","DOI":"10.1093\/neuros\/nyx388","article-title":"Cervical spine deformity\u2014part 2: management algorithm and anterior techniques","volume":"81","author":"Tan LA","year":"2017","unstructured":"Tan LA, Riew KD, Traynelis VC: Cervical spine deformity\u2014part 2: management algorithm and anterior techniques. Neurosurgery 81:561\u2013567, 201710.1093\/neuros\/nyx38828934448"},{"key":"b25","series-title":"Neurosurgery","doi-asserted-by":"publisher","first-page":"662","DOI":"10.1227\/NEU.0b013e31826100c9","article-title":"The impact of standing regional cervical sagittal alignment on outcomes in posterior cervical fusion surgery","volume":"71","author":"Tang JA","year":"2012","unstructured":"Tang JA, Scheer JK, Smith JS, Deviren V, Bess S, Hart RA, : The impact of standing regional cervical sagittal alignment on outcomes in posterior cervical fusion surgery. Neurosurgery 71:662\u2013669, 20122265339510.1227\/NEU.0b013e31826100c9"}],"container-title":["Journal of Neurosurgery: Spine"],"original-title":[],"link":[{"URL":"https:\/\/thejns.org\/view\/journals\/j-neurosurg-spine\/32\/3\/article-p353.xml","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/thejns.org\/downloadpdf\/journals\/j-neurosurg-spine\/32\/3\/article-p353.xml","content-type":"text\/html","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/thejns.org\/downloadpdf\/journals\/j-neurosurg-spine\/32\/3\/article-p353.xml","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,4,15]],"date-time":"2023-04-15T22:55:53Z","timestamp":1681599353000},"score":1,"resource":{"primary":{"URL":"https:\/\/thejns.org\/view\/journals\/j-neurosurg-spine\/32\/3\/article-p353.xml"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,3]]},"references-count":25,"journal-issue":{"issue":"3"},"URL":"https:\/\/doi.org\/10.3171\/2019.9.spine19730","relation":{},"ISSN":["1547-5654"],"issn-type":[{"value":"1547-5654","type":"print"}],"subject":[],"published":{"date-parts":[[2020,3]]}}}