Does discography injure normal discs? An analysis of repeat discograms.

This study was done to look for evidence of damage to a healthy disc resulting from diagnostic discography. Thirty-four patients had undergone a second discogram at 80 lumbar levels. There were 22 men and 12 women. The mean interval between discograms was 16.7 months (range, 3-38). Of 42 levels that were reported to be radiologically normal on the first discogram, ten were reported to be abnormal on the second discogram (24%). On review of these films, the abnormality was in fact present on the first discogram at two levels, and the second discogram was normal at two levels (radiologist error). Fusions had been done in three patients at adjacent levels between discograms. A compression fracture was present in adjacent vertebrae at two levels. Only one level was found to be truly abnormal on the second discogram for no obvious reason. The authors found no evidence that diagnostic discography damaged a normal disc.