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    Patent Pending

    Mirels’ Criteria for Prophylactic Fixation

    Predicts risk of pathologic fracture in patients with long bone metastasis.
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    INSTRUCTIONS

    Use in patients with known long bone metastasis. Do not use if history of fracture or previous irradiation.

    When to Use
    Pearls/Pitfalls

    Patients with known long bone metastasis, without history of fracture or previous irradiation.

    • Shown to have greater variability in agreement when scored by medical and radiation oncologists, to whom these patients are most likely to present.
    • Can only be used to predict fracture risk in long bones (i.e., not in vertebral mets).
    • Better validated than the earlier Harrington Criteria.
    • While the original paper describes the size of the lesion as a percentage of the cortex, in practice it is classified as a percentage of the width (diameter) of the bone at that level.
    • Predicts fracture risk in the 6 months after radiotherapy, which may not be relevant for many patients (i.e., if no plans for radiotherapy and/or short life expectancy).
    Upper limb
    +1
    Lower limb
    +2
    Trochanteric region
    +3
    Less than 1/3 of bone diameter
    +1
    1/3 to 2/3 of bone diameter
    +2
    More than 2/3 of bone diameter
    +3
    Blastic
    +1
    Mixed
    +2
    Lytic
    +3
    Mild
    +1
    Moderate
    +2
    Functional
    +3

    Result:

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    Next Steps
    Evidence
    Creator Insights

    Advice

    In addition to Mirels’ Criteria, consider patient-specific factors such as comorbidities, predicted survival, other sites of disease, activity level, and bone mineral density when deciding whether or not to recommend prophylactic fixation.

    Formula

    Addition of selected points:

     

    Score

    1

    2

    3

    Site of lesion

    Upper limb

    Lower limb

    Trochanteric region

    Size of lesion

    <⅓ of bone diameter

    ⅓-⅔ of bone diameter

    >⅔ of bone diameter

    Nature of lesion

    Blastic

    Mixed

    Lytic

    Pain

    Mild

    Moderate

    Functional

    Facts & Figures

    Interpretation:

    Score

    Fracture risk*

    Recommendation

    ≤7

    0-4%

    Safe to irradiate with minimal risk of fracture

    8

    15%

    Consider prophylactic fixation

    ≥9

    >33%

    Prophylactic fixation indicated

    *At 6 months post-irradiation.

    Dr. Hilton Mirels

    About the Creator

    Hilton Mirels, MD, is an orthopaedic surgeon and has been in practice for almost 40 years. He completed his training at the University of the Witwatersrand in Johannesburg, South Africa. Dr. Mirels is best known for his eponymous criteria for long bone fracture.

    To view Dr. Hilton Mirels's publications, visit PubMed

    About the Creator
    Dr. Hilton Mirels