{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,24]],"date-time":"2026-09-24T01:59:37Z","timestamp":1790215177542,"version":"4.1.0"},"reference-count":8,"publisher":"Scientific Scholar","content-domain":{"domain":["surgicalneurologyint.com"],"crossmark-restriction":true},"short-container-title":[],"abstract":"\nBackground: <\/jats:title>\nThe healing process after C1-C2 posterior screw fixation (C1-C2 PSF) for odontoid fractures is not well understood. Here, we evaluated such processes and identified factors potentially contributing to pseudoarthroses following fusions for Type II odontoid fractures.<\/jats:p>\n<\/jats:sec>\n\nMethods: <\/jats:title>\nPre- and post-operative cervical radiographs and computed tomography (CT) images from 15 patients with preoperative Type II odontoid fractures who underwent C1-C2 PSF were retrospectively reviewed.<\/jats:p>\n<\/jats:sec>\n\nResults: <\/jats:title>\nCT images identified three areas of bone fusion: The primary fracture site in the dens (9\/15 patients, 60%), the atlanto-dental interspace (ADI) (10\/15, 67%), and C1-C2 interlaminar space after onlay bone grafting (4\/15, 27%). All patients showed bone fusion in at least one of three areas, while only one patient (6.7%) achieved bone fusion in all three areas. With these overall criteria, nine of 15 patients (60%) were considered fused, while six patients (40%) were determined to exhibit pseudoarthroses. Univariate analyzes showed that the preoperative C2-C7 SVA for the nonunion group was significantly larger versus the union group, and bone fusion at the level of the ADI was significantly more common in the nonunion versus the union group.<\/jats:p>\n<\/jats:sec>\n\nConclusion: <\/jats:title>\nCT studies identified three anatomical areas where bone fusion likely occurs after C1-C2 PSF. Increased sagittal balance in the cervical spine may negatively impact the fusion of odontoid fractures. Further, bone fusion occurring at other sites, not the primary fracture location, through stress shielding may contribute to delayed or failed fusions.<\/jats:p>\n<\/jats:sec>","DOI":"10.25259\/sni_198_2022","type":"journal-article","created":{"date-parts":[[2022,3,31]],"date-time":"2022-03-31T09:33:54Z","timestamp":1648719234000},"page":"116","update-policy":"https:\/\/doi.org\/10.25259\/crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Healing process of Type II odontoid fractures after C1-C2 posterior screw fixation: Predictive factors for pseudoarthrosis"],"prefix":"10.25259","volume":"13","author":[{"given":"Satoshi","family":"Yamaguchi","sequence":"first","affiliation":[{"name":"Department of Neurosurgery, University of Iowa Hospitals and Clinics, Iowa City, United States,"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Brian J.","family":"Park","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, University of Iowa Hospitals and Clinics, Iowa City, United States,"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Masaaki","family":"Takeda","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima City, Hiroshima, Japan,"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Takafumi","family":"Mitsuhara","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima City, Hiroshima, Japan,"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kiyoharu","family":"Shimizu","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima City, Hiroshima, Japan,"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pei-Fu","family":"Chen","sequence":"additional","affiliation":[{"name":"Department of Anesthesiology, Far Eastern Memorial Hospital, New Taipei City, Taiwan."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Royce W.","family":"Woodroffe","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, University of Iowa Hospitals and Clinics, Iowa City, United States,"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"10894","published-online":{"date-parts":[[2022,3,31]]},"reference":[{"key":"10.25259\/SNI_198_2022\/ref-1","doi-asserted-by":"crossref","first-page":"1663","DOI":"10.2106\/00004623-197456080-00017","article-title":"Fractures of the odontoid process of the axis","volume":"56","author":"Anderson","year":"1974","journal-title":"J Bone Joint Surg Am"},{"key":"10.25259\/SNI_198_2022\/ref-2","doi-asserted-by":"crossref","first-page":"274","DOI":"10.1055\/s-0034-1376192","article-title":"The fate of Type II odontoid fractures after posterior atlantoaxial fusion: Where does healing occur?","volume":"76","author":"Bisson","year":"2015","journal-title":"J Neurol Surg A Cent Eur Neurosurg"},{"key":"10.25259\/SNI_198_2022\/ref-3","doi-asserted-by":"crossref","first-page":"313","DOI":"10.1097\/BSD.0000000000000872","article-title":"Odontoid fractures: A critical review of current management and future directions","volume":"32","author":"Carvalho","year":"2019","journal-title":"Clin Spine Surg"},{"key":"10.25259\/SNI_198_2022\/ref-4","doi-asserted-by":"crossref","first-page":"43","DOI":"10.1007\/s00402-018-3050-6","article-title":"Mortality, complication, and fusion rates of patients with odontoid fracture: The impact of age and comorbidities in 204 cases","volume":"139","author":"Charles","year":"2019","journal-title":"Arch Orthop Trauma Surg"},{"key":"10.25259\/SNI_198_2022\/ref-5","doi-asserted-by":"crossref","first-page":"e1087","DOI":"10.1016\/j.wneu.2018.05.172","article-title":"Odontoid fracture in patients age >75 years surgically managed by the harms technique: Bone healing and 1-year mortality rate in 57 cases","volume":"116","author":"Faure","year":"2018","journal-title":"World Neurosurg"},{"key":"10.25259\/SNI_198_2022\/ref-6","doi-asserted-by":"crossref","first-page":"e242","DOI":"10.5435\/JAAOS-D-17-00277","article-title":"The healing rate of Type II odontoid fractures treated with posterior atlantoaxial screw-rod fixation: A retrospective review of 77 patients","volume":"27","author":"Huang","year":"2019","journal-title":"J Am Acad Orthop Surg"},{"key":"10.25259\/SNI_198_2022\/ref-7","doi-asserted-by":"crossref","first-page":"e417","DOI":"10.1016\/j.wneu.2017.09.198","article-title":"Predisposing factors of fracture nonunion after posterior C1 lateral mass screws combined with C2 pedicle\/laminar screw fixation for Type II odontoid fracture","volume":"109","author":"Wang","year":"2018","journal-title":"World Neurosurg"},{"key":"10.25259\/SNI_198_2022\/ref-8","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1186\/s13018-017-0702-0","article-title":"The comparison of clinical outcome of fresh Type II odontoid fracture treatment between anterior cannulated screws fixation and posterior instrumentation of C1-2 without fusion: A retrospective cohort study","volume":"13","author":"Yuan","year":"2018","journal-title":"J Orthop Surg Res"}],"container-title":["Surgical Neurology 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