Sacral destruction: foraminal lines revisited.

Although imaging techniques have improved greatly in recent years, plain radiography remains the initial imaging method for evaluation of patients with low back pain. The sacrum, in particular, is a difficult structure to evaluate. In reviewing 12 cases, the authors found an unacceptably high rate of missed sacral metastases (83%). Using a photograph and a radiograph of two bony pelvic specimens to represent normal anatomy and the normal appearance of the sacral foraminal lines, sacral destruction is illustrated in six cases. All lesions were neoplastic and most were metastatic. In each case there was destruction of one or more sacral lines. The importance of careful observation for symmetric appearance of these lines is emphasized.