Original Mirels Score for Metastatic Long-Bone Lesions
A source-specific guide to the 1989 score, historical risk table, threshold conflict, and safe interpretation.
Use the source-locked interpreter: Original Mirels Score for Metastatic Long-Bone Lesions (1989)
What this route implements
The calculator reproduces the original additive score for an intact metastatic long-bone lesion assessed clinically and on reviewed plain radiographs. It does not analyze images, derive a lesion-size ratio, calculate a proprietary model, or select treatment.
The source categories are:
| Domain | 1 point | 2 points | 3 points | | --- | --- | --- | --- | | Site | Upper-limb long bone | Lower-limb long bone except trochanteric femur | Trochanteric region of femur | | Pain | Mild | Moderate | Functional | | Lesion nature | Blastic | Mixed | Lytic | | Size | Less than one third | One third through two thirds inclusive | More than two thirds |
“Functional” is the source pain category. It should not be replaced by a generic “severe” label. Size is a clinician-selected categorical estimate from radiographs, not a numeric fraction submitted to the calculator.
Original cohort and historical lookup
Mirels retrospectively assessed 78 long-bone lesions in 38 patients. The lesions were scored before irradiation, received irradiation without prophylactic fixation, and were observed for fracture over six months.
| Total | Historical fracture observation | | ---: | ---: | | 4 | 0% | | 5 | 0% | | 6 | 0% | | 7 | 4% | | 8 | 15% | | 9 | 33% | | 10 | 72% | | 11 | 96% | | 12 | 100% |
These values describe a small historical cohort. They are not individualized current probabilities, certainty statements, or proof that a particular treatment is safe.
Score 8 source conflict: the primary PubMed abstract says lesions scoring 8 or higher required fixation before irradiation. The commonly reproduced clinical table instead presents 8 as a clinical-judgment zone and 9 or higher as the fixation threshold. The calculator reports that conflict rather than silently choosing one source statement.
Neutral threshold interpretation
- Totals 4-7: below the commonly used original-model
>=9threshold. This is not a declaration that radiotherapy alone is safe or that fracture cannot occur. - Total 8: the explicit source-conflict zone, with a historical cohort observation of 15%.
- Totals 9-12: meet the commonly used original-model impending-fracture threshold. At total 9, the historical observation is exactly 33%, not greater than 33%. Timely orthopedic or orthopedic-oncology assessment is appropriate, but the score does not mandate fixation.
Management depends on current imaging, lesion mechanics, symptoms, prognosis, systemic disease, goals, and specialist judgment. The route does not determine fixation, radiotherapy, activity or weight-bearing instructions, or any other treatment.
Applicability and transportability
The original score applies to eligible long bones. Spine, pelvis outside the proximal femur, ribs, scapula, skull, small bones, primary bone tumors, benign lesions, completed fractures, stabilized lesions, and cases without reviewed plain radiographs are outside scope.
The original cohort included study-era disease and treatment conditions. Multiple myeloma and previously irradiated lesions therefore receive explicit transportability warnings rather than false contemporary calibration. Low external specificity and observer variability also limit use of the score in isolation.
Modified Mirels systems and proposed upper-limb thresholds such as >=7 are separate models. They are not substituted into this original 1989 calculator.
Sources
- Mirels H. Metastatic disease in long bones. Clin Orthop Relat Res. 1989;(249):256-264. PubMed
- Jawad MU, Scully SP. Classifications in Brief: Mirels’ Classification. PMC
- Damron TA and colleagues. Fracture risk assessment and clinical decision making. PMC
- Long-bone fracture-risk review. PMC
- Evans AR and colleagues. Humeral validation and threshold analysis. PMC
- Mah SJ and colleagues. Internal validation of a modified Mirels system. PMC