PURPOSE AND MATERIAL: Contrast-enhanced MR imaging of the spine after surgery for lumbar disk herniation almost always shows pathologic changes. To investigate to what extent these changes are correlated to patients' actual clinical symptoms, we compared the postoperative MR findings in 19 asymptomatic patients with 42 symptomatic patients (43 levels).
Methods: The asymptomatic patients underwent MR examination one year after surgery. Twenty-six of the symptomatic patients underwent MR one year or less after surgery, and in 16 patients (17 levels) MR was performed more than one year after surgery.
Results: Sixteen percent of the asymptomatic and 42% of the symptomatic patients had disk herniation at the level of previous surgery. Most of the herniated disks were found in the symptomatic patients less than one year after surgery. The amount of epidural scar tissue, displacement and thickening of nerve roots, and compression of the dural sac were also studied. Disk herniation as a probable cause of recurrent sciatica was a common finding among symptomatic patients examined one year or less after surgery. In comparing asymptomatic patients and symptomatic patients with more than one year between surgery and MR examination, no significant radiologic differences, including disk herniation, were found.