Mirels proposes a weighted scoring system to predict pathologic fracture through metastatic long bone lesions. Four factors (site, pain, lesion type, size) are each scored 1 to 3 for a maximum of 12. The study tests whether the combined score outperforms any single risk factor.
When you see a long bone metastasis, run the Mirels score before deciding on radiation versus fixation. Score each of four variables 1 to 3: site, pain, lesion type, size.
The decision rule: a score of 9 or higher is diagnostic of impending fracture and warrants prophylactic fixation before irradiation, because radiating a mechanically compromised bone risks a completed fracture in a poor surgical candidate.
A score of 7 or lower (about 5% fracture risk) can be irradiated alone. A score of 8 is the gray zone: get a CT to better characterize the lesion and weigh surgical risk against a 15% fracture probability.
The key teaching point is that the combined score beats any single factor. Do not fixate on lesion size or pain alone. Functional pain and lytic destruction over two-thirds of the cortex are the strongest individual warning signs, but the summed score is what should drive management.
Mirels proposes a weighted scoring system to predict pathologic fracture through metastatic long bone lesions. Four factors (site, pain, lesion type, size) are each scored 1 to 3 for a maximum of 12. The study tests whether the combined score outperforms any single risk factor.
When you see a long bone metastasis, run the Mirels score before deciding on radiation versus fixation. Score each of four variables 1 to 3: site, pain, lesion type, size.
The decision rule: a score of 9 or higher is diagnostic of impending fracture and warrants prophylactic fixation before irradiation, because radiating a mechanically compromised bone risks a completed fracture in a poor surgical candidate.
A score of 7 or lower (about 5% fracture risk) can be irradiated alone. A score of 8 is the gray zone: get a CT to better characterize the lesion and weigh surgical risk against a 15% fracture probability.
The key teaching point is that the combined score beats any single factor. Do not fixate on lesion size or pain alone. Functional pain and lytic destruction over two-thirds of the cortex are the strongest individual warning signs, but the summed score is what should drive management.