Ilio-Sacral Pathology

The sacrum is a complex-shaped osseous structure present at the base of the axial spine. This bone plays a vital role in weight-bearing in the ambulant adult. Because of its shape and position, lesions of the sacrum are often slow to present, as there is considerable room from tumor growth in the pelvis. Nonspecific symptoms such as vague lower back pain are frequent early manifestations of lesions in this bone. Fractures and inflammatory diseases often affect the sacrum, in addition to bone-specific tumors and systemic malignancies. Plain radiography is frequently used in initial evaluation, but its efficacy is limited as sacral lesions are often difficult to visualize; because of the shape of the bone itself, its position deep in the pelvis, the presence of overlying soft-tissue structures and the presence of fecal material and bowel gas in the sigmoid colon and rectum.