[The reliability of computer tomography in the diagnosis of recurrent symptoms after lumbar disc operations].

In 67 patients with recurrent complaints after operations of herniated lumbar disks, the CT findings were compared with the results of the subsequent second operation. Postoperative complications as haemorrhages or inflammations appear as localised or diffuse densities within the spinal canal in the operated segment and can be diagnosed without difficulty. The differentiation between a true recurrent herniation and scar formation is difficult, mainly within the first 4 weeks after operation. Even with the administration of iv. contrast medium, the diagnostic accuracy is not higher than 70%. In addition to the enhancement effect, which is not always reliable, the shape, position and density of a suspected structure can be used as diagnostic criteria.