Lumbar spine after surgery: examination with intravenous contrast-enhanced CT.

Computed tomography (CT) of the lumbar spine without and with intravenous administration of contrast medium was performed in 143 consecutive patients who had previously had spine surgery for disk herniation and had persistent or recurrent symptoms. Fifty-two patients underwent surgical reexploration. It was possible to make the diagnosis of normal postoperative status, disk herniation, or scarring in 31 (60%) of the 52 patients with the use of CT scans without intravenous contrast medium. CT with intravenous contrast enhancement was useful in 12 of the remaining patients (23%). Enhancement of the margins of a herniated disk occurred in 37 (71%) of the patients. There was near-homogeneous enhancement of postoperative scarring in 34 (65%) patients. Intravenous contrast medium was particularly helpful when disk herniation and scarring were both present, by delineating the margins of a herniated disk and enhancing the entire substance of the scar. In symptomatic postoperative patients, CT of the lumbar spine without intravenous contrast medium should be performed initially. If a definitive diagnosis is not established, CT with intravenous contrast enhancement should be considered.