Bilsky ESCC Epidural spinal cord compression (ESCC / Bilsky) scale

{
  "categories": [
    {
      "outcome_code": "0",
      "label": "bone_only",
      "epidural_tumor": "absent",
      "thecal_sac_deformation": "absent",
      "cord_abutment": "absent",
      "cord_compression": "absent",
      "CSF_around_cord": "preserved"
    },
    {
      "outcome_code": "1a",
      "label": "epidural_impingement",
      "epidural_tumor": "present",
      "thecal_sac_deformation": "absent",
      "cord_abutment": "absent",
      "cord_compression": "absent",
      "CSF_around_cord": "preserved"
    },
    {
      "outcome_code": "1b",
      "label": "thecal_sac_deformation_without_cord_abutment",
      "epidural_tumor": "present",
      "thecal_sac_deformation": "present",
      "cord_abutment": "absent",
      "cord_compression": "absent",
      "CSF_around_cord": "preserved"
    },
    {
      "outcome_code": "1c",
      "label": "cord_abutment_without_compression",
      "epidural_tumor": "present",
      "thecal_sac_deformation": "present",
      "cord_abutment": "present",
      "cord_compression": "absent",
      "CSF_around_cord": "no_interposed_CSF_at_contact_but_no_cord_compression"
    },
    {
      "outcome_code": "2",
      "label": "cord_compression_with_residual_CSF",
      "epidural_tumor": "present",
      "thecal_sac_deformation": "present",
      "cord_abutment": "present",
      "cord_compression": "present",
      "CSF_around_cord": "visible"
    },
    {
      "outcome_code": "3",
      "label": "cord_compression_without_residual_CSF",
      "epidural_tumor": "present",
      "thecal_sac_deformation": "present",
      "cord_abutment": "present",
      "cord_compression": "present",
      "CSF_around_cord": "not_visible"
    }
  ],
  "applicability": {
    "intended_use": "Describe the maximal degree of neoplastic epidural spinal cord compromise at each involved level, principally in metastatic spine disease.",
    "reference_image": "Axial T2-weighted MRI at the site of most severe compression; use the full multiplanar examination to localize the level, confirm tumor extent and avoid a partial-volume classification.",
    "required_anatomy": "A spinal cord level where epidural tumor, thecal sac, spinal cord and surrounding CSF can be assessed.",
    "outside_scope": [
      "mechanical_instability_or_pathologic_fracture_scoring_use_SINS_separately",
      "non_neoplastic_epidural_abscess_hematoma_disc_or_postoperative_material",
      "intramedullary_or_intradural_extramedullary_tumor_without_neoplastic_epidural_extension",
      "treatment_selection_without_tumor_radiosensitivity_prior_radiation_stability_neurology_and_systemic_fitness"
    ]
  },
  "acquisition_and_quality_gate": {
    "suspected_MSCC_current_MRI": "When metastatic spinal cord compression is clinically suspected with neurologic signs or symptoms, current NICE guidance calls for MRI as soon as possible and always within 24 hours; an elective classification workflow must not delay that pathway.",
    "whole_spine_protocol_context": "Current NICE guidance uses sagittal T1 and/or STIR through the whole spine, sagittal T2 to show cord or cauda-equina compression, and supplementary axial imaging through every significant abnormality.",
    "grade_plane": "Assign the ESCC grade on axial T2 at maximal compression, cross-checked against sagittal and adjacent axial images.",
    "technical_failure": "Motion, incomplete coverage, severe artifact or absent axial T2 at the maximal level makes the grade indeterminate; do not infer it from a single sagittal image."
  },
  "grading_algorithm": [
    {
      "step": 1,
      "question": "Is tumor confined to bone without epidural extension?",
      "if_yes": "0",
      "if_no": "continue"
    },
    {
      "step": 2,
      "question": "Is there epidural impingement without thecal-sac deformation?",
      "if_yes": "1a",
      "if_no": "continue"
    },
    {
      "step": 3,
      "question": "Is the thecal sac deformed but the cord not abutted?",
      "if_yes": "1b",
      "if_no": "continue"
    },
    {
      "step": 4,
      "question": "Does tumor abut the cord without deforming/compressing it?",
      "if_yes": "1c",
      "if_no": "continue"
    },
    {
      "step": 5,
      "question": "Is the cord compressed but CSF remains visible around it?",
      "if_yes": "2",
      "if_no": "continue"
    },
    {
      "step": 6,
      "question": "Is the cord compressed with no visible surrounding CSF?",
      "if_yes": "3",
      "if_no": "ungradable_or_wrong_scope"
    }
  ],
  "boundary_rules": {
    "grade_0_1a": "The decisive boundary is epidural extension: bone-only disease is 0; epidural impingement that has not deformed the thecal sac is 1a.",
    "grade_1a_1b": "Thecal-sac deformation moves 1a to 1b even before cord contact.",
    "grade_1b_1c": "Actual cord abutment moves 1b to 1c; proximity without demonstrable contact is not 1c.",
    "grade_1c_2": "Cord contact alone is 1c; deformation/compression of the cord is required for 2.",
    "grade_2_3": "Residual visible CSF around a compressed cord is 2; complete loss of visible CSF at the maximal compression site is 3.",
    "adjacent_uncertainty": "If a boundary feature cannot be resolved, return the adjacent-grade interval and the missing discriminator rather than a false exact grade."
  },
  "per_level_and_study_synthesis": {
    "level_rule": "Grade every clinically relevant involved cord level separately and identify the axial image/series used.",
    "headline_rule": "The study headline may name the highest grade, but it must retain all other levels rather than collapsing multilevel disease into one patient-level code.",
    "required_companions": [
      "vertebral_and_posterior_element_tumor_extent",
      "epidural_direction_and_craniocaudal_length",
      "cord_signal_abnormality",
      "pathologic_fracture_or_retropulsion",
      "alignment",
      "paraspinal_extension"
    ],
    "progression_rule": "On follow-up, preserve the prior level-specific grade, treatment interval and direction of change; do not overwrite trajectory with only the new maximum."
  },
  "cauda_equina_and_conus_boundary": {
    "original_scale": "The original definitions refer to spinal cord compression.",
    "current_emergency_scope": "Modern MSCC pathways also address cauda-equina compression, so urgent clinical handling still applies below the conus.",
    "agent_rule": "If the morphology is adapted to a cauda-equina level, label it explicitly as an adaptation and describe root/CSF effacement directly; do not imply identical original validation."
  },
  "NOMS_integration": {
    "neurologic": "Combine ESCC morphology with myelopathy, radiculopathy and the neurologic examination; ESCC is the radiographic component, not the complete neurologic assessment.",
    "oncologic": "Tumor histology, radiosensitivity, molecular context and prior radiation determine whether conventional radiation, stereotactic radiation or decompression is feasible.",
    "mechanical": "Score or describe stability separately, commonly with SINS. A low ESCC grade can coexist with an unstable painful fracture, and a high ESCC grade does not itself encode instability.",
    "systemic": "Performance status, systemic disease burden, comorbidity, expected tolerance, available options and goals of care constrain treatment.",
    "low_grade_context": "In NOMS, grades 0, 1a and 1b are low-grade epidural disease and are often considered for radiation-first treatment when there is no mechanical instability, but this is conditional on oncologic and systemic factors.",
    "grade_1c_context": "The original NOMS publication identifies uncertainty regarding the role and durability of radiosurgery for grade 1c; do not silently treat 1c as either the low-grade or high-grade algorithm.",
    "high_grade_context": "Grades 2 and 3 are high-grade ESCC. Except for highly radiosensitive tumors, NOMS commonly considers decompression before radiation; current ASTRO guidance conditionally favors surgery plus postoperative radiation over radiation alone in appropriate patients with cord or cauda-equina compression.",
    "non_autonomous_rule": "No ESCC category autonomously orders surgery, radiation, steroid treatment, transfer or surveillance."
  },
  "urgency_and_clinical_override": {
    "red_flags": [
      "new_or_progressive_weakness",
      "gait_decline_or_loss_of_ambulation",
      "sensory_level",
      "new_bowel_or_bladder_dysfunction",
      "myelopathy",
      "rapidly_progressive_radicular_deficit"
    ],
    "action_rule": "Known or suspected cancer plus cord/cauda-equina compression symptoms is an oncologic emergency requiring immediate local MSCC escalation; do not wait for an exact ESCC grade.",
    "clinical_fields_to_capture": [
      "neurologic_baseline",
      "time_of_onset_and_rate_of_decline",
      "ambulation",
      "bowel_and_bladder_status",
      "pain_and_mechanical_features",
      "corticosteroid_status",
      "prior_spine_treatment"
    ]
  },
  "evidence_and_risk_interpretation": {
    "reliability": "The 2010 study validated reproducible six-category MRI morphology among readers; reliability does not make the scale a standalone outcome model.",
    "ordinal_warning": "Increasing grade represents increasing epidural compromise, but it is not a calibrated individual probability of paralysis, recovery or survival.",
    "treatment_evidence_warning": "NOMS, NICE and ASTRO provide decision context beyond the scale. Their recommendations must be applied to the actual clinical population, tumor and local pathway rather than copied as grade-only commands."
  },
  "agent_output_contract": [
    "exact_level_and_maximal_axial_T2_image",
    "exact_ESCC_grade_or_adjacent_grade_uncertainty",
    "epidural_extent_direction_and_length",
    "cord_compression_and_cord_signal_separately",
    "fracture_alignment_and_mechanical_stability_context_separately",
    "neurologic_red_flags_and_time_course_when_available",
    "tumor_histology_radiosensitivity_prior_radiation_and_systemic_context_when_available",
    "explicit_urgent_escalation_if_MSCC_is_suspected",
    "no_grade_only_treatment_or_prognostic_probability"
  ],
  "missing_input_behavior": [
    "If axial T2 at maximal compression is unavailable or nondiagnostic, return ungradable and request/identify the missing sequence rather than assigning from sagittal images alone.",
    "If cord contact versus compression cannot be resolved, return 1c-versus-2 and name cord deformation plus residual CSF as the unresolved features.",
    "If compression is present but residual CSF cannot be assessed, return 2-versus-3 rather than guessing.",
    "If neurologic status is absent, report imaging morphology only and withhold urgency based on symptoms, functional prognosis and treatment selection.",
    "If pathology, prior radiation, stability or systemic fitness is absent, do not produce a NOMS treatment recommendation."
  ],
  "supporting_sources": [
    {
      "role": "primary_scale",
      "citation": "Bilsky et al. J Neurosurg Spine. 2010;13:324-328",
      "doi": "10.3171/2010.3.SPINE09459",
      "pmid": "20809724"
    },
    {
      "role": "multidisciplinary_framework",
      "citation": "Laufer et al. Oncologist. 2013;18:744-751",
      "doi": "10.1634/theoncologist.2012-0293",
      "pmcid": "PMC4063402"
    },
    {
      "role": "current_emergency_pathway",
      "citation": "NICE NG234. 2023",
      "url": "https://www.nice.org.uk/guidance/ng234/chapter/recommendations"
    },
    {
      "role": "current_radiation_guideline",
      "citation": "Alcorn et al. Pract Radiat Oncol. 2024",
      "doi": "10.1016/j.prro.2024.04.018",
      "pmid": "38788923"
    }
  ],
  "source_locator": "Bilsky et al. 2010, DOI 10.3171/2010.3.SPINE09459, abstract and six-point definitions for axial T2 grading and reliability; Laufer et al. 2013, PMC4063402, Neurologic Assessment and Oncologic Assessment sections and Figure 1 for low/high-grade NOMS integration and the grade 1c uncertainty; NICE NG234 recommendations 1.5.2-1.5.5 for urgent MRI and sequences; ASTRO 2024 guideline abstract for cord/cauda-equina compression treatment context."
}