There have been few innovations in the management of penetrating trauma of the flank and back since that reported by Peck and Berne in 1981. During 1984-1985 our Trauma Service treated 119 patients with injuries in these areas. In 56 patients management was based on the results of the contrast-enhanced CT enema (CECTE), a computerized tomographic technique designed to delineate all of the retroperitoneal viscera by simultaneously opacifying the small bowel, duodenum, colon, GU tract, and major vessels. Specific radiographic findings were present on 44 scans. Twelve scans were negative. Six scans were considered indications for angiography because of the proximity of the identified missile wounds or their hematomas to major vascular structures. One of these arteriograms revealed a renal artery pseudoaneurysm which would otherwise have remained undiagnosed. In 30 cases the penetrating wounds were well delineated by CECTE, and their nature and location were considered appropriate for nonoperative management. None required subsequent exploration. In eight cases CECTE demonstrated that the wounds were located so as to place specific viscera at risk for significant injury, but no definite injury was identified. Five of these patients were successfully managed by further evaluation and close observation, two were explored, and one signed out of the hospital. No scan demonstrated extravasation from a hollow viscus. Overall, 52 of our 56 patients (92%) were successfully managed nonoperatively on the basis of the interpretation of their CECTE findings. CECTE can be useful in the management of stable patients with penetrating trauma to the back and flank by identifying the nature and location of the resulting retroperitoneal injuries.(ABSTRACT TRUNCATED AT 250 WORDS)