Mirels classification is a system used to predict the highest risk of pathological fracture among long bones affected by metastases
- based on site, location, matrix and/or presence of pain
Classification
- 1 point
- upper limb
- involving <1/3 of bone diameter
- blastic/sclerotic lesion
- mild pain
- 2 points
- lower limb
- involving 1/3-2/3 of bone diameter
- mixed sclerotic/lytic lesion
- moderate pain
- 3 points
- trochanteric region
- involves >2/3 of bone diameter
- lytic lesion
- functional pain
This will give a minimum score of four and a maximum score of 12
- a score of >=9 suggests that prophylactic fixation should be performed (1,2)
- for score 8 lesions
- treatment is based on clinical judgement and for lower scores clinical management and radiotherapy is suggested
The overall sensitivity of the Mirel classification predicting fracture is approximately 90%
- however specificity is only 35%
- this means that there will be unnecessary fixations) leading to debate about its usefulness (1,3)
Reference:
- Jawad MU, Scully SP. In brief: classifications in brief: Mirels' classification: metastatic disease in long bones and impending pathologic fracture. Clin. Orthop. Relat. Res. 2010;468 (10): 2825-7
- Rockwood CA, Bucholz RW, M.D. CC et-al. Rockwood and Green's Fractures in Adults. Lippincott Williams & Wilkins. (2010) ISBN:1605476773
- Piccioli A, Spinelli MS, Maccauro G. Impending fracture: A difficult diagnosis. (2014) Injury. 45 Suppl 6: S138-41. doi:10.1016/j.injury.2014.10.038