{
    "abstract": "Study designAn umbrella systematic review.ObjectiveTo identify historically recognized injury characteristics that may affect treatment decisions of traumatic C2 injuries and help improve the description of the \"modifiers\" presented in the AO Upper Cervical Injury Classification (UCIC).MethodsWe performed an umbrella review of systematic reviews evaluating studies about the management of axis fractures that identify potential modifiers in the treatment of these injuries. These modifiers were grouped according to the new AO UCIC.ResultsEight systematic reviews were included. They were divided into three groups: (1) Axis body fractures - one study, (2) Hangman\u00b4s fractures - one study, and (3) Odontoid fractures, six studies. For axis body fractures, most injuries were treated non-operatively, except some Benzel type 3 fractures (AO Type A) with displacement or severe comminution (M1). Hangman\u00b4s fractures classified as Effendi I and Levine-Edwards I and II were treated non-operatively with success, with no modifiers identified for non-union or instability. For Levine-Edwards type IIA and III surgery was generally recommended, but these should be classified as AO type B and C respectively without a need for modifiers. For odontoid fractures, fractures in the dens base, with displacement, or in elderly patients were associated with non-union (M1) and patients' specific factors (surgical condition) seem to affect the decision of treatment (M3) for considering surgery.ConclusionsWe identified from the literature some axis injury characteristics that seem to affect the treatment decision in historical series. Knowledge of these modifiers may further enhance the system's clinical utility.",
    "authors": [
        {
            "affiliation": "Neurosurgery Division, Department of Neurology, State University of Campinas, Campinas-Sao Paulo, Brazil.",
            "firstname": "Andrei F",
            "initials": "AF",
            "lastname": "Joaquim"
        },
        {
            "affiliation": "Department of Orthopaedic Surgery and Traumatology, Inselspital, University Hospital, University of Bern, Bern, Switzerland.",
            "firstname": "Sebastian F",
            "initials": "SF",
            "lastname": "Bigdon"
        },
        {
            "affiliation": "Department of Orthopaedic Surgery, Policlinica Gipuzkoa, Gipuzkoa, Spain.",
            "firstname": "Gaston",
            "initials": "G",
            "lastname": "Camino-Willhuber"
        },
        {
            "affiliation": "Department of Orthopedics, University Medical Centers, Utrecht, the Netherlands.",
            "firstname": "Cumhur F",
            "initials": "CF",
            "lastname": "\u00d6ner"
        },
        {
            "affiliation": "Center for Spinal and Scoliosis Surgery, Malteser Waldkrankenhaus St. Marien Erlangen, Erlangen, Germany.\nDepartment of Orthopedics and Traumatology, Paracelsus Private Medical University Nuremberg, Nuremberg, Germany.",
            "firstname": "Klaus J",
            "initials": "KJ",
            "lastname": "Schnake"
        },
        {
            "affiliation": "Department of Orthopaedic Surgery and Sports Medicine, Harborview Medical Center, University of Washington, Seattle, WA, USA.",
            "firstname": "Richard",
            "initials": "R",
            "lastname": "Bransford"
        },
        {
            "affiliation": "Department of Spine and Rehabilitation, Sri Balaji Action Medical Institute, New Delhi, India.",
            "firstname": "Harvinder Singh",
            "initials": "HS",
            "lastname": "Chhabra"
        },
        {
            "affiliation": "Department of Orthopaedic and Trauma Surgery, Faculty of Medicine, Assiut University, Assiut, Egypt.",
            "firstname": "Mohammad",
            "initials": "M",
            "lastname": "El-Skarkawi"
        },
        {
            "affiliation": "Department of Orthopaedic Surgery, Rothman Institute at Thomas Jefferson University Hospital, Philadelphia, PA, USA.",
            "firstname": "Alexander R",
            "initials": "AR",
            "lastname": "Vaccaro"
        },
        {
            "affiliation": "Department of Orthopaedic Surgery, Rothman Institute at Thomas Jefferson University Hospital, Philadelphia, PA, USA.",
            "firstname": "Gregory D",
            "initials": "GD",
            "lastname": "Schroeder"
        },
        {
            "affiliation": null,
            "firstname": null,
            "initials": null,
            "lastname": null
        }
    ],
    "conclusions": null,
    "copyrights": null,
    "doi": "10.1177/21925682251333300\n10.1179/2045772313Y.0000000158\n10.1097/01.CNE.0000383190.33761.f2\n10.1186/s13018-022-03147-9\n10.1016/j.spinee.2022.08.005\n10.1016/j.spinee.2022.11.005\n10.1093/neuros/nyz464\n10.1136/bmj.n71\n10.1136/bmj.j4008\n10.1097/BSD.0000000000000309\n10.1136/bmj.39489.470347\n10.1227/00006123-198508000-00006\n10.1097/00007632-199708150-00009\n10.3171/spi.2000.93.2.0227\n10.1302/0301-620x.81b3.9109\n10.3171/2009.7.SPINE0991\n10.1007/s00586-005-0918-2\n10.1007/s00586-012-2452-3\n10.1227/NEU.0000000000000942\n10.1177/21925682231157316\n10.3171/2023.6.SPINE22920\n10.1007/s00586-023-07779-1\n10.1016/j.jamcollsurg.2017.11.005\n10.1177/21925682241288187",
    "journal": "Global spine journal",
    "keywords": [
        "C2",
        "axis fractures",
        "axis injuries",
        "treatment",
        "upper cervical trauma"
    ],
    "methods": null,
    "publication_date": "2025-03-29",
    "pubmed_id": "40156313\n24559418\n35568925\n4434035\n7263741\n3772485\n3945481\n35964830\n36396008\n31642504\n33782057\n28935701\n29176489\n18436948\n8027803\n2809718\n4033879\n9280020\n11012053\n10872369\n8877952\n3175749\n19951016\n16235100\n22941218\n26378359\n27163167\n37084350\n37877937\n37439865\n29155268\n39327898",
    "results": null,
    "title": "The AO Spine Upper Cervical Injury Classification System (AO UCIC) - An Umbrella Review of Traumatic Axis Injuries Factors that May Affect Treatment Decision.",
    "xml": "<Element 'PubmedArticle' at 0x788504bb89a0>"
}