{
  "abstract": "Study DesignNarrative review.ObjectiveTo clarify nuances when applying the AO Spine Primary Infection Classification.MethodsThe international validation of the AO Spine Primary Infection Classification System was successful but recurring themes caused confusion. This included the exact definition and reasons for infections to transition between categories, definition of canal involvement or neural compression and whether an epidural infection superimposed on degenerative disease escalates infection severity. There was uncertainty regarding handling of multi-level or junctional infection and clinicians encountered difficulty applying the modifiers.ResultsThe difference between a Type 0 and Type 1 infection is reasonably distinct given the former is purely extraspinal whilst the latter involves spondylodiscitis or osteomyelitis without canal involvement. Type 2 infections include those with any canal involvement, regardless of whether CSF effacement occurs, in the absence of neural compression. The spinal canal is defined as the compartment dorsal to the posterior longitudinal ligament and excludes infections that are ventral to this ligament but bow into the canal. Any neural compression of the thecal sac centrally or within the foramen escalates categorization to a Type 3 infection.ConclusionsPrimary spinal infections have the potential to rapidly progress and cause devastating neurological deficits. The introduction of the AO Spine Primary Infection Classification establishes a universal language to communicate disease severity. We clarify common nuances encountered during international validation of this system including definition of canal involvement and relevance of CSF effacement, whether foraminal involvement constitutes neural compression and the nomenclature concerning multi-level or junctional disease.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Spine and Neurotrauma, National Trauma Research Institute, Melbourne, VIC, Australia.",
    "Department of Neurosurgery, The Alfred Hospital, Melbourne, VIC, Australia.",
    "Department of Neurosurgery, Royal Melbourne Hospital, Parkville, VIC, Melbourne.",
    "Department of Orthopaedic Surgery, Rothman Institute, Thomas Jefferson University Hospital, Philadelphia, PA, USA.",
    "Department of Neurosurgery, Prince Mohammed Bin Abdulaziz Hospital, Riyadh, Saudi Arabi.",
    "Department of Orthopaedic and Trauma Surgery, Faculty of Medicine, Assiut University, Assiut, Egypt.",
    "Combined Neurosurgical and Orthopedic Spine Program, Vancouver General Hospital, University of British Columbia, Vancouver, Canada.",
    "Center for Spinal Surgery and Neurosurgery, Berufsgenossenschaftliche Unfallklinik Frankfurt Am Main, Frankfurt-Ost, Germany.",
    "Department of Neurosurgery, LMU University Hospital, Munich, Germany.",
    "Department of Orthopaedics, University of Utah, Salt Lake City, UT, USA.",
    "Department of Orthopaedic Surgery, Stanford University, Redwood City, CA, USA.",
    "Department of Orthopaedic Surgery, Sri Balaji Action Medical Institute, New Delhi, India.",
    "Harborview Medical Center, University of Washington, Seattle, WA, USA.",
    "Neurosurgery Division, Department of Neurology, State University of Campinas, Campinas, Sao Paulo, Brazil.",
    "Central Clinical School, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, VIC, Australia."
  ],
  "article_type": "review article",
  "arxiv": null,
  "author_total": 13,
  "authors": [
    {
      "affs": [
        0,
        1,
        2
      ],
      "name": "Barry Ting Sheen Kweh",
      "orcid": "0000-0001-9130-1543"
    },
    {
      "affs": [
        3
      ],
      "name": "Alexander R Vaccaro"
    },
    {
      "affs": [
        3
      ],
      "name": "Gregory Schroeder"
    },
    {
      "affs": [
        4
      ],
      "name": "Mohamed Aly",
      "orcid": "0000-0001-5221-8288"
    },
    {
      "affs": [
        5
      ],
      "name": "Mohammad El-Sharkawi",
      "orcid": "0000-0001-6177-7145"
    },
    {
      "affs": [
        6
      ],
      "name": "Charlotte Dandurand",
      "orcid": "0000-0002-4520-6454"
    },
    {
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        7,
        8
      ],
      "name": "Jonathan Neuhoff"
    },
    {
      "affs": [
        9
      ],
      "name": "Brian Karamian",
      "orcid": "0000-0003-0512-6019"
    },
    {
      "affs": [
        10
      ],
      "name": "Grace Xiong"
    },
    {
      "affs": [
        11
      ],
      "name": "Harvinder Singh Chhabra"
    },
    {
      "affs": [
        12
      ],
      "name": "Richard Bransford",
      "orcid": "0000-0003-2293-5774"
    },
    {
      "affs": [
        13
      ],
      "name": "Andrei Fernandes Joaquim",
      "orcid": "0000-0003-2645-0483"
    },
    {
      "affs": [
        0,
        1,
        14
      ],
      "name": "Jin Wee Tee"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/f07j2w0n7k0ms.bib",
  "cited_by": 0,
  "doi": "10.1177/21925682261498682",
  "fulltext_url": "https://europepmc.org/articles/PMC13669232",
  "id": "f07j2w0n7k0ms",
  "issns": [
    "2192-5682",
    "2192-5690"
  ],
  "landing_url": "https://europepmc.org/article/MED/42874070",
  "language": "eng",
  "licence": "CC-BY-NC-ND",
  "licence_label": "CC BY-NC-ND",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "2746|Infectious Diseases and Tuberculosis"
    ]
  ],
  "openalex": "W7221830878",
  "pdf_url": "https://europepmc.org/articles/PMC13669232?pdf=render",
  "pmcid": "PMC13669232",
  "pmid": "42874070",
  "published": "2026-10-14",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/f07j2w0n7k0ms.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:46Z",
      "native_id": "MED:42874070",
      "source": "europepmc",
      "url": "https://europepmc.org/article/MED/42874070"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "openalex:2746|Infectious Diseases and Tuberculosis",
      "subfield": "surgery"
    }
  ],
  "title": "Practical Application of the AO Spine Primary Infection Classification System: Clarifying Definitions, Borderline Cases and Common Misinterpretations.",
  "title_text": "Practical Application of the AO Spine Primary Infection Classification System: Clarifying Definitions, Borderline Cases and Common Misinterpretations.",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:46Z",
  "url": "https://research.draconitic.com/paper/f07j2w0n7k0ms",
  "venue": "Global spine journal",
  "versions": []
}