{
  "abstract": "Kambin's triangle is a useful geometric model for lumbar transforaminal access, but the clinically usable corridor is patient specific because the exiting nerve root, dorsal root ganglion (DRG), traversing neural structures, anatomic variants, and disease-related displacement may alter the contemplated path. We evaluated volumetric magnetic resonance imaging (MRI) root mapping as a method for characterizing nerve-root anatomy relevant to patient-specific transforaminal trajectory planning. This retrospective descriptive MRI-anatomy study analyzed 76 selected patients who underwent volumetric 3D T2-weighted MRI root mapping between March 1, 2022 and March 12, 2026 during evaluation of symptomatic lumbar levels before contemplated transforaminal or percutaneous disc access. Sixteen earlier contrast-assisted cases are mentioned only as historical technique-development context and were not included in the MRI analysis. Multiplanar, oblique, and curved reconstructions were reviewed collaboratively by a radiologist with musculoskeletal/spine imaging involvement and the operating surgeon/radiology team. Trajectory assessment distinguished anatomically favorable, borderline, and unfavorable/high-risk relationships, including dimensional incompatibility and direct neural trajectory conflict. Nine of the 76 patients (11.8%) demonstrated one of the two predefined nerve-root findings relevant to the intended transforaminal trajectory. Four unique patients had double or variant nerve roots occupying the intended Kambin corridor. Five additional unique patients had displacement of the exiting nerve root into the planned cannula trajectory; three were considered unfavorable/high-risk and two borderline. The two groups did not overlap. The abnormalities were identified at L4-5 in five patients, L5-S1 in three, and L3-4 in one. The remaining 67 patients did not demonstrate either predefined finding and are not interpreted as a validated safe comparator group. None of the nine relevant cases generated a material disagreement regarding the root-course abnormality or its relationship to the contemplated trajectory. Volumetric MRI may identify patient-specific neural anatomy relevant to transforaminal trajectory and route planning. Its contribution is trajectory-oriented visualization rather than proof of procedural safety or diagnostic superiority over routine MRI. The observed frequency in this selected symptomatic-level cohort is descriptive and should not be interpreted as the population prevalence of aberrant nerve-root anatomy.",
  "abstract_shown": true,
  "affiliations": [
    "RIWO Spine Center of Excellence, Department of Neurosurgery, Foundation Hospital Centro Médico Campinas, Campinas, Brazil.",
    "Division of Personalized Pain Research and Education, Center for Advanced Spine Care of Southern Arizona, Tucson, AZ, USA.",
    "Department of Orthopaedics, Fundación Universitaria Sanitas, Bogotá D.C., Colombia.",
    "Department of Orthopedics, Hospital Universitário Gaffrée e Guinle, Universidade Federal do Estado do Rio de Janeiro, Rio de Janeiro, Brazil.",
    "Department of Orthopedic Surgery, University of Arizona Tucson Campus, Tucson, AZ, USA.",
    "Centre for Musculoskeletal Surgery (CMSC), Berlin, Germany.",
    "Klinik für Unfall-, Hand- und Wiederherstellungschirurgie, Universitätsklinikum des Saarlandes, Homburg, Germany.",
    "Próton Radiologia, Hospital Centro Médico Campinas, Campinas, Brazil.",
    "Department of Orthopaedic Surgery & Sports Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA.",
    "Latin American Endoscopic Spine Surgeons LESS Invasiva Academy, Bogotá D.C., Colombia.",
    "Grupo de Investigación en Ortopedia y Traumatología, Departamento de Ortopedia y Traumatología, Clínica Colsanitas S.A., Bogotá D.C., Colombia.",
    "Programa de Ortopedia y Traumatología, Facultad de Medicina, Fundación Universitaria Sanitas, Bogotá D.C., Colombia.",
    "Unidad de Investigación, Fundación Universitaria Sanitas, Bogotá D.C., Colombia."
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 8,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Antonio Roth Vargas",
      "orcid": "0000-0003-0343-9687"
    },
    {
      "affs": [
        1,
        2,
        3,
        4,
        5,
        6
      ],
      "name": "Kai-Uwe Lewandrowski",
      "orcid": "0000-0001-7842-2914"
    },
    {
      "affs": [
        7
      ],
      "name": "Alexandre Borges",
      "orcid": "0000-0002-5707-7565"
    },
    {
      "affs": [
        5
      ],
      "name": "Celine C Akta",
      "orcid": "0009-0008-7472-9212"
    },
    {
      "affs": [
        8
      ],
      "name": "Theresa J C Pazionis",
      "orcid": "0000-0003-3894-3605"
    },
    {
      "affs": [
        5
      ],
      "name": "Tom Folkerts",
      "orcid": "0009-0008-6597-8348"
    },
    {
      "affs": [
        5
      ],
      "name": "Matthias Pumberger",
      "orcid": "0000-0002-0885-7370"
    },
    {
      "affs": [
        9,
        10,
        11,
        12
      ],
      "name": "Jorge Felipe Ramírez León",
      "orcid": "0000-0003-2145-0417"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/5rr6nmqwkqfjy.bib",
  "cited_by": 0,
  "doi": "10.21037/jss-2026-0180",
  "fulltext_url": "https://europepmc.org/articles/PMC13739642",
  "id": "5rr6nmqwkqfjy",
  "issns": [
    "2414-469X",
    "2414-4630"
  ],
  "landing_url": "https://europepmc.org/article/MED/42996268",
  "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",
      "2732|Spine and Intervertebral Disc Pathology"
    ]
  ],
  "openalex": "W7223809721",
  "pdf_url": "https://europepmc.org/articles/PMC13739642?pdf=render",
  "pmcid": "PMC13739642",
  "pmid": "42996268",
  "published": "2026-10-23",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/5rr6nmqwkqfjy.ris",
  "sources": [
    {
      "first_seen": "2026-11-09T15:20:34Z",
      "native_id": "MED:42996268",
      "source": "europepmc",
      "url": "https://europepmc.org/article/MED/42996268"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "openalex:2732|Spine and Intervertebral Disc Pathology",
      "subfield": "surgery"
    }
  ],
  "title": "When the safe triangle is unsafe: volumetric magnetic resonance imaging root mapping for patient-specific assessment of Kambin's triangle before transforaminal lumbar disc procedures.",
  "title_text": "When the safe triangle is unsafe: volumetric magnetic resonance imaging root mapping for patient-specific assessment of Kambin's triangle before transforaminal lumbar disc procedures.",
  "type": "peer-reviewed",
  "updated_at": "2026-11-09T15:20:34Z",
  "url": "https://research.draconitic.com/paper/5rr6nmqwkqfjy",
  "venue": "Journal of spine surgery (Hong Kong)",
  "versions": []
}