{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,14]],"date-time":"2026-08-14T20:32:48Z","timestamp":1786739568813,"version":"build-2736575974"},"reference-count":46,"publisher":"Ovid Technologies (Wolters Kluwer Health)","issue":"3","license":[{"start":{"date-parts":[[2026,5,1]],"date-time":"2026-05-01T00:00:00Z","timestamp":1777593600000},"content-version":"unspecified","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0"}],"content-domain":{"domain":["lww.com","ovid.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2026,5]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Objective:<\/jats:title>\n                    <jats:p>To compare computed tomography (CT) scan-based morphometric measures associated with atlanto-occipital joint (AOJ) instability between Chiari malformation type I (CMI) patients and controls and to examine associations between these measures, clinical symptoms, and established craniocervical\/posterior fossa morphometrics in CMI.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Materials and Methods:<\/jats:title>\n                    <jats:p>\n                      Four AOJ-related morphometric measures were evaluated on CT: condyle\u2013C1 interval (CCI), C1 socket depth-to-length ratio (DL ratio), condyle depth-to-depth ratio (CD ratio), and atlas tilt angle. Measurements were compared between CMI (\n                      <jats:italic toggle=\"yes\">n<\/jats:italic>\n                      = 45) and controls (\n                      <jats:italic toggle=\"yes\">n<\/jats:italic>\n                      = 55). Within CMI, associations were tested between AOJ measures and symptom variables, as well as 13 established craniocervical\/posterior fossa morphometrics.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results:<\/jats:title>\n                    <jats:p>\n                      Mean CCI was slightly larger in CMI than in controls (1.00 vs. 0.91 mm,\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      &lt; 0.05). DL ratio, CD ratio, and atlas tilt angle did not differ significantly between groups. Within CMI, CCI showed a modest association with hypermobility (\n                      <jats:italic toggle=\"yes\">r<\/jats:italic>\n                      = 0.34,\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      &lt; 0.05). Moderate correlations were observed between AOJ measures and selected morphometrics, suggesting relationships between AOJ geometry and posterior fossa\/craniocervical anatomy.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion:<\/jats:title>\n                    <jats:p>Among the AOJ measures examined, only CCI demonstrated a small but statistically significant group difference and a modest association with hypermobility in CMI. The shape of the AOJ curvature was not different between CMI and control. However, further investigation of AOJ-related morphometrics as potential contributors to symptom heterogeneity among CMI patients is necessary.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.4103\/jcvjs.jcvjs_44_26","type":"journal-article","created":{"date-parts":[[2026,5,20]],"date-time":"2026-05-20T09:00:25Z","timestamp":1779267625000},"page":"236-243","update-policy":"https:\/\/doi.org\/10.1097\/lww.0000000000001000","source":"Crossref","is-referenced-by-count":0,"title":["An examination of atlanto-occipital curvature in adult Chiari malformation type 1 and control groups"],"prefix":"10.4103","volume":"17","author":[{"given":"Mahsa","family":"Karamzadeh","sequence":"first","affiliation":[{"name":"Department of Bioengineering, Northeastern University, Boston, MA, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mohamad Motaz","family":"Al Samman","sequence":"additional","affiliation":[{"name":"Department of Bioengineering, Northeastern University, Boston, MA, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rick","family":"Labuda","sequence":"additional","affiliation":[{"name":"Conquer Chiari, Wexford, PA, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rafeeque A.","family":"Bhadelia","sequence":"additional","affiliation":[{"name":"Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jonathan A.","family":"Millard","sequence":"additional","affiliation":[{"name":"Department of Biomedical Sciences, Edward Via College of Osteopathic Medicine, Blacksburg, VA, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Paul D","family":"Bishop","sequence":"additional","affiliation":[{"name":"Department of Vascular Surgery, Cleveland Clinic, Cleveland, OH, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Philip A.","family":"Allen","sequence":"additional","affiliation":[{"name":"Department of Psychology, University of Akron, Akron, OH, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Thomas J","family":"Fultz","sequence":"additional","affiliation":[{"name":"Department of Vascular Surgery, Cleveland Clinic, Cleveland, OH, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Scott B.","family":"Raymond","sequence":"additional","affiliation":[{"name":"Neurological Institute, Cleveland Clinic, Cleveland, OH, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jenny P.","family":"Tsai","sequence":"additional","affiliation":[{"name":"Neurological Institute, Cleveland Clinic, Cleveland, OH, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Muhammad Shazam","family":"Hussain","sequence":"additional","affiliation":[{"name":"Cerebrovascular Center, Cleveland Clinic, OH, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rouzbeh","family":"Amini","sequence":"additional","affiliation":[{"name":"Department of Bioengineering, Northeastern University, Boston, MA, USA"},{"name":"Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Francis","family":"Loth","sequence":"additional","affiliation":[{"name":"Department of Bioengineering, Northeastern University, Boston, MA, USA"},{"name":"Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"276","published-online":{"date-parts":[[2026,5,20]]},"reference":[{"key":"R1-20260520","doi-asserted-by":"crossref","first-page":"1005","DOI":"10.1097\/00006123-199905000-00042","article-title":"Chiari I malformation redefined:Clinical and radiographic findings for 364 symptomatic patients","volume":"44","author":"Milhorat","year":"1999","journal-title":"Neurosurgery"},{"key":"R2-20260520","first-page":"215","article-title":"Chiari malformations:Diagnosis, treatments and failures","volume":"58","author":"Abd-El-Barr","year":"2014","journal-title":"J Neurosurg Sci"},{"key":"R3-20260520","doi-asserted-by":"crossref","first-page":"e9","DOI":"10.1016\/j.wneu.2019.05.098","article-title":"Chiari I malformation:Opinions on diagnostic trends and controversies from a panel of 63 international experts","volume":"130","author":"Bolognese","year":"2019","journal-title":"World Neurosurg"},{"key":"R4-20260520","doi-asserted-by":"crossref","first-page":"161","DOI":"10.3171\/2014.10.PEDS14295","article-title":"Pediatric and adult Chiari malformation type I surgical series 1965-2013:A review of demographics, operative treatment, and outcomes","volume":"15","author":"Arnautovic","year":"2015","journal-title":"J Neurosurg Pediatr"},{"key":"R5-20260520","doi-asserted-by":"crossref","first-page":"242","DOI":"10.25259\/SNI_377_2019","article-title":"Multidimensional, patient-reported outcome after posterior fossa decompression in 79 patients with Chiari malformation type I","volume":"10","author":"De Vlieger","year":"2019","journal-title":"Surg Neurol Int"},{"key":"R6-20260520","doi-asserted-by":"crossref","first-page":"116","DOI":"10.3171\/2014.10.SPINE14176","article-title":"Is atlantoaxial instability the cause of Chiari malformation?Outcome analysis of 65 patients treated by atlantoaxial fixation","volume":"22","author":"Goel","year":"2015","journal-title":"J Neurosurg Spine"},{"key":"R7-20260520","doi-asserted-by":"crossref","first-page":"110740","DOI":"10.1016\/j.mehy.2021.110740","article-title":"A new hypothesis for the pathophysiology of symptomatic adult Chiari malformation Type I","volume":"158","author":"Labuda","year":"2022","journal-title":"Med Hypotheses"},{"key":"R8-20260520","doi-asserted-by":"crossref","first-page":"636","DOI":"10.4184\/asj.2015.9.4.636","article-title":"Craniovertebral junction instability:A review of facts about facets","volume":"9","author":"Goel","year":"2015","journal-title":"Asian Spine J"},{"key":"R9-20260520","doi-asserted-by":"crossref","first-page":"2925","DOI":"10.1007\/s00701-020-04557-6","article-title":"Chiari malformation type I and basilar invagination originating from atlantoaxial instability:A literature review and critical analysis","volume":"162","author":"Meyer","year":"2020","journal-title":"Acta Neurochir (Wien)"},{"key":"R10-20260520","doi-asserted-by":"crossref","first-page":"131","DOI":"10.1016\/j.nec.2022.09.006","article-title":"Craniovertebral junction instability in the setting of Chiari malformation","volume":"34","author":"Dastagirzada","year":"2023","journal-title":"Neurosurg Clin N Am"},{"key":"R11-20260520","doi-asserted-by":"crossref","first-page":"186","DOI":"10.14245\/ns.1938138.069","article-title":"A review of a new clinical entity of 'central atlantoaxial instability':Expanding horizons of craniovertebral junction surgery","volume":"16","author":"Goel","year":"2019","journal-title":"Neurospine"},{"key":"R12-20260520","doi-asserted-by":"crossref","first-page":"66","DOI":"10.3171\/2024.1.PEDS23229","article-title":"The role of occipital condyle and atlas anomalies on occipital cervical fusion outcomes in Chiari malformation type I with syringomyelia:A study from the park-reeves syringomyelia research consortium","volume":"34","author":"Yahanda","year":"2024","journal-title":"J Neurosurg Pediatr"},{"key":"R13-20260520","doi-asserted-by":"crossref","first-page":"194","DOI":"10.1007\/s12311-021-01289-w","article-title":"Adult age differences in self-reported pain and anterior CSF space in Chiari malformation","volume":"21","author":"Garc\u00eda","year":"2022","journal-title":"Cerebellum"},{"key":"R14-20260520","doi-asserted-by":"crossref","first-page":"299","DOI":"10.3171\/2024.7.SPINE24370","article-title":"Correlation of anterior CSF space in the cervical spine with Chicago Chiari outcome scale score in adult females","volume":"42","author":"Allen","year":"2025","journal-title":"J Neurosurg Spine"},{"key":"R15-20260520","doi-asserted-by":"crossref","first-page":"e921","DOI":"10.1016\/j.wneu.2020.06.076","article-title":"Chiari 1 formation redefined-clinical and radiographic observations in 388 surgically treated patients","volume":"141","author":"Goel","year":"2020","journal-title":"World Neurosurg"},{"key":"R16-20260520","doi-asserted-by":"crossref","first-page":"847","DOI":"10.4184\/asj.2017.11.6.847","article-title":"Computed tomography-based occipital condyle morphometry in an Indian population to assess the feasibility of condylar Screws for occipitocervical fusion","volume":"11","author":"Srivastava","year":"2017","journal-title":"Asian Spine J"},{"key":"R17-20260520","doi-asserted-by":"crossref","first-page":"470","DOI":"10.1016\/j.wneu.2020.01.150","article-title":"Occipital condyle screw placement in patients with Chiari malformation:A radiographic feasibility analysis and cadaveric demonstration","volume":"136","author":"Kirnaz","year":"2020","journal-title":"World Neurosurg"},{"key":"R18-20260520","doi-asserted-by":"crossref","first-page":"201","DOI":"10.1016\/j.wneu.2021.05.033","article-title":"Role of atlas assimilation in the context of craniocervical junction anomalies","volume":"151","author":"Joaquim","year":"2021","journal-title":"World Neurosurg"},{"key":"R19-20260520","doi-asserted-by":"crossref","first-page":"1755","DOI":"10.1007\/s00381-019-04284-z","article-title":"Chiari malformation and atlantoaxial instability:Problems of co-existence","volume":"35","author":"Chatterjee","year":"2019","journal-title":"Childs Nerv Syst"},{"key":"R20-20260520","doi-asserted-by":"crossref","first-page":"191","DOI":"10.1016\/j.clineuro.2004.07.014","article-title":"Morphometric analysis of human occipital condyle","volume":"107","author":"Naderi","year":"2005","journal-title":"Clin Neurol Neurosurg"},{"key":"R21-20260520","doi-asserted-by":"crossref","first-page":"161","DOI":"10.1007\/s00276-019-02344-2","article-title":"Morphometric analysis of occipital condyles using alternative imaging technique","volume":"42","author":"Gumussoy","year":"2020","journal-title":"Surg Radiol Anat"},{"key":"R22-20260520","doi-asserted-by":"crossref","first-page":"1569","DOI":"10.1007\/s00701-021-04714-5","article-title":"Feasibility of occipital condyle screw placement in patients with Chiari malformation type I:A computed tomography-based morphometric study","volume":"163","author":"Wan","year":"2021","journal-title":"Acta Neurochir (Wien)"},{"key":"R23-20260520","doi-asserted-by":"crossref","first-page":"149","DOI":"10.1016\/j.wneu.2023.09.112","article-title":"The effect of posterior fossa decompression surgery on brainstem and cervical spinal cord dimensions in adults with Chiari malformation type 1","volume":"180","author":"Karamzadeh","year":"2023","journal-title":"World Neurosurg"},{"key":"R24-20260520","doi-asserted-by":"crossref","first-page":"392","DOI":"10.4103\/jcvjs.jcvjs_160_25","article-title":"Atlantal facet geometry in Chiari I malformation","volume":"16","author":"Millard","year":"2025","journal-title":"J Craniovertebr Junction Spine"},{"key":"R25-20260520","doi-asserted-by":"crossref","first-page":"5472","DOI":"10.3390\/jcm11185472","article-title":"The small posterior cranial fossa syndrome and Chiari malformation Type 0","volume":"11","author":"Bogdanov","year":"2022","journal-title":"J Clin Med"},{"key":"R26-20260520","doi-asserted-by":"crossref","first-page":"731","DOI":"10.1007\/s10439-018-02175-z","article-title":"Quantification of cerebellar crowding in type I Chiari malformation","volume":"47","author":"Biswas","year":"2019","journal-title":"Ann Biomed Eng"},{"key":"R27-20260520","doi-asserted-by":"crossref","first-page":"521","DOI":"10.1016\/j.wneu.2020.02.182","article-title":"Posterior fossa dimensions of Chiari malformation patients compared with normal subjects:Systematic review and meta-analysis","volume":"138","author":"Botelho","year":"2020","journal-title":"World Neurosurg"},{"key":"R28-20260520","doi-asserted-by":"crossref","first-page":"1117","DOI":"10.1007\/s00701-010-0636-3","article-title":"Mechanisms of cerebellar tonsil herniation in patients with Chiari malformations as guide to clinical management","volume":"152","author":"Milhorat","year":"2010","journal-title":"Acta Neurochir (Wien)"},{"key":"R29-20260520","first-page":"e1891","article-title":"Occipital neuralgia in Chiari I malformation:Two different events or two different faces of the same event?","volume":"9","author":"Tondo","year":"2017","journal-title":"Cureus"},{"key":"R30-20260520","doi-asserted-by":"crossref","first-page":"12","DOI":"10.1080\/02688697.2020.1823940","article-title":"A morphometric study of the atlanto-occipital joint in adult patients with Chiari malformation type I","volume":"38","author":"Wan","year":"2024","journal-title":"Br J Neurosurg"},{"key":"R31-20260520","doi-asserted-by":"crossref","first-page":"837","DOI":"10.1227\/neu.0000000000002284","article-title":"Exploring the pathogenesis of atlanto-occipital instability in Chiari malformation with type II basilar invagination:A systematic morphological study","volume":"92","author":"Huang","year":"2023","journal-title":"Neurosurgery"},{"key":"R32-20260520","doi-asserted-by":"crossref","first-page":"514","DOI":"10.1227\/01.NEU.0000290897.77448.1F","article-title":"Atlanto-occipital dislocation:Part 1 \u2013Normal occipital condyle-C1 interval in 89 children","volume":"61","author":"Pang","year":"2007","journal-title":"Neurosurgery"},{"key":"R33-20260520","doi-asserted-by":"crossref","first-page":"227","DOI":"10.3171\/2019.4.PEDS1968","article-title":"Morphometric changes at the craniocervical junction during childhood","volume":"24","author":"Bapuraj","year":"2019","journal-title":"J Neurosurg Pediatr"},{"key":"R34-20260520","doi-asserted-by":"crossref","first-page":"952","DOI":"10.3174\/ajnr.A4543","article-title":"Normal development and measurements of the occipital condyle-C1 interval in children and young adults","volume":"37","author":"Smith","year":"2016","journal-title":"AJNR Am J Neuroradiol"},{"key":"R35-20260520","doi-asserted-by":"crossref","first-page":"535","DOI":"10.3171\/2015.6.SPINE15226","article-title":"Computed tomography parameters for atlantooccipital dislocation in adult patients:The occipital condyle-C1 interval","volume":"24","author":"Martinez-Del-Campo","year":"2016","journal-title":"J Neurosurg Spine"},{"key":"R36-20260520","doi-asserted-by":"crossref","first-page":"27","DOI":"10.1007\/s10143-023-02249-0","article-title":"Craniocervical instability in patients with Ehlers-Danlos syndromes:Outcomes analysis following occipito-cervical fusion","volume":"47","author":"Henderson","year":"2024","journal-title":"Neurosurg Rev"},{"key":"R37-20260520","first-page":"211","article-title":"Quantification of iris concavity","volume":"5","author":"Amini","year":"2010","journal-title":"J Ophthalmic Vis Res"},{"key":"R38-20260520","doi-asserted-by":"crossref","first-page":"529","DOI":"10.1055\/s-0035-1569058","article-title":"The Application of the revised condyle-C1 interval method to diagnose traumatic atlanto-occipital dissociation in adults","volume":"6","author":"Dahdaleh","year":"2016","journal-title":"Global Spine J"},{"key":"R39-20260520","doi-asserted-by":"crossref","first-page":"837","DOI":"10.1227\/neu.0000000000002284","article-title":"Exploring the pathogenesis of atlanto-occipital instability in Chiari malformation with type II basilar invagination:A systematic morphological study","volume":"92","author":"Huang","year":"2023","journal-title":"Neurosurgery"},{"key":"R40-20260520","doi-asserted-by":"crossref","first-page":"100173","DOI":"10.1016\/j.wnsx.2023.100173","article-title":"Chiari I malformation management in patients with heritable connective tissue disorders","volume":"18","author":"Clarke","year":"2023","journal-title":"World Neurosurg\u00d7"},{"key":"R41-20260520","doi-asserted-by":"crossref","first-page":"23","DOI":"10.1016\/j.neurad.2017.06.006","article-title":"A morphometric assessment of type I Chiari malformation above the McRae line:A retrospective case-control study in 302 adult female subjects","volume":"45","author":"Houston","year":"2018","journal-title":"J Neuroradiol"},{"key":"R42-20260520","doi-asserted-by":"crossref","first-page":"915","DOI":"10.1007\/s10143-018-01070-4","article-title":"Cervical medullary syndrome secondary to craniocervical instability and ventral brainstem compression in hereditary hypermobility connective tissue disorders:5-year follow-up after craniocervical reduction, fusion, and stabilization","volume":"42","author":"Henderson","year":"2019","journal-title":"Neurosurg Rev"},{"key":"R43-20260520","doi-asserted-by":"crossref","first-page":"454","DOI":"10.3340\/jkns.2015.58.5.454","article-title":"Stereological and morphometric analysis of MRI Chiari malformation type-1","volume":"58","author":"Alko\u00e7","year":"2015","journal-title":"J Korean Neurosurg Soc"},{"key":"R44-20260520","doi-asserted-by":"crossref","first-page":"2202","DOI":"10.1007\/s00586-016-4410-y","article-title":"Morphometric features of posterior cranial fossa are different between Chiari I malformation with and without syringomyelia","volume":"25","author":"Yan","year":"2016","journal-title":"Eur Spine J"},{"key":"R45-20260520","doi-asserted-by":"crossref","first-page":"111093","DOI":"10.1016\/j.jbiomech.2022.111093","article-title":"Statistical shape models of the posterior cranial fossa and hindbrain volumes may provide a more robust clinical metric for Chiari malformation","volume":"137","author":"Lloyd","year":"2022","journal-title":"J Biomech"},{"key":"R46-20260520","doi-asserted-by":"crossref","first-page":"175","DOI":"10.4103\/tcmj.tcmj_62_20","article-title":"Embryological considerations and evaluation of congenital anomalies of craniovertebral junction:A single-center experience","volume":"33","author":"Ravikanth","year":"2021","journal-title":"Tzu Chi Med J"}],"container-title":["Journal of Craniovertebral Junction and Spine"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.ovid.com\/10.4103\/jcvjs.jcvjs_44_26","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,14]],"date-time":"2026-08-14T19:30:05Z","timestamp":1786735805000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.ovid.com\/10.4103\/jcvjs.jcvjs_44_26"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,5]]},"references-count":46,"journal-issue":{"issue":"3","published-print":{"date-parts":[[2026]]}},"URL":"https:\/\/doi.org\/10.4103\/jcvjs.jcvjs_44_26","relation":{},"ISSN":["0974-8237","0976-9285"],"issn-type":[{"value":"0974-8237","type":"print"},{"value":"0976-9285","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,5]]},"assertion":[{"value":"2026-02-06","name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2026-02-20","name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}}]}}