The diagnosis of sacral lesions.

Clinical courses are reviewed in 4 recent patients with sacral lesions, each of whom was believed on initial clinical evaluation to have symptomatic herniations of intervertebral discs. In each patient pain in the back tended to overshadow radicular symptoms, and sphincteric disturbances were not prominent. Each patient presented some related objective abnormality on general or neurologic examination. The sacral lesion was invariably visible on technically satisfactory plain roentgenograms of the spine and was obvious on sacral tomography. Conventional myelography was useful in defining communication between the lesion and the subarachnoid space, but otherwise typically it was only subtly and nonspecifically abnormal. Computerized tomography (CT) proved to be the most revealing radiographic technique, demonstrating bony detail as well as internal structure and extent of the lesion; in conjunction with metrizamide myelography, CT provided the most definitive anatomical study. The limited utility of angiography in diagnosing these lesions is discussed, as are the respective hazards of and indications for needle biopsy and open surgical exploration.