||In an attempt to determine the expected long-term
appearance of the lumbar spine in patients who have undergone successful
lumbar discectomy, follow-up magnetic resonance (MR) examinations were performed
on 23 patients (26 levels). All patients in the study had undergone at surgery
at least one year prior to the study. All patients met rigorous criteria
for a successful outcome. In nine cases, the postoperative study indicated
a virtually total resolution of the previously identified disc herniations.
In 13 cases, the study noted moderate, persistent posterior contour defects
in the disc that contributed to persistent mass effect on the thecal sac
or corresponding nerve root. In the remaining four cases, the postoperative
study indicated virtually no change in the apparent contour of the posterior
disc margin. Gadolinium contrast examinations demonstrated enhancement of
the persistent contour abnormalities in 18 of 19 disc levels, suggesting
the common presence of fibrosis, which was at times "mass-like,"
in these successful patients. These findings suggest that localized discal
contour abnormalities morphologically simulating recurrent disc herniations
and variably contributing to mass effect, may be commonly encountered in
long-term follow-up imaging studies of successful discectomy patients.