Prediction of spinal epidural metastases

Context: Early diagnosis and treatment of spinal epidural metastases (SEM) is of the utmost importance to present neurological deficit due to spinal c ord compression. Magnetic resonance imaging (MRI) has become the final tool in that diagnostic process. However, access to MRI is still limited in the Netherlands, requiring cost-effective use. It is generally acknowledged th at patients with systemic cancer who present with a radiculopathy or myelop athy should undergo an MRI. However, the diagnostic policy in patients with systemic cancer who present with recently developed back pain is still a m atter of debate. Objective: To identify the patients with back pain in whom MRI can safely b e omitted because of a low risk of SEM. Methods: In a prospective series of 170 consecutive patients with cancer wi th recently developed back pain, prediction of spinal metastatic disease (S MD) and especially SEM was studied by means of a multivariate risk analysis of the parameters of the standard neurological evaluation (medical history , neurological examination, and plain films of the whole spine). Magnetic r esonance imaging was used as the criterion standard. We calculated the risk implications of omitting MRI in patients with an estimated risk below diff erent cutoff points. Results: Spinal metastatic disease was diagnosed in 80 patients (47%); of t hese, 31 had SEM. A metastatic abnormality on plain films was the strongest independent predictor for SMD. Other important predictors were night pain, progressive pain, and Karnofsky score. Advanced age, exacerbation of pain during recumbency, and osteoporotic fracture imply a low risk of SMD. Night pain and the Karnofsky score proved to be the main predictors for SEM. A p lain film showing an osteoporotic fracture strongly decreased the risk of S EM. The discriminating value of the multivariate analysis was too low, and too few patients can be excluded from undergoing MRI on the basis of the st andard neurological checkup. To identify all the patients with SMD (P<.01), MRI would be excluded in only 7 patients. Identification of all patients w ith SEM (P<.001) reduced the number of MRIs by 21 at the expense of plain f ilms of the whole spine for any patient. Conclusions: Selection of patients with cancer with back pain at risk of SE M was not possible with the standard neurological checkup. After intake by the neurologist, the next step should be MRI of the whole spine.