Discography in Failed Back Syndrome

Gordon Tang, MD
Andrew Silverstein, MD
Regis Haid, MD
Gerald Rodts, MD (Atlanta, GA)

Introduction:

Discography is well described for the diagnosis of discogenic pain. However, its use has not been studied in patients who have failed prior lumbar surgery. We aim to determine the utility of discography in this patient subgroup.

Methods:

Retrospective review of 75 patients with prior lumbar surgery who underwent 197 discograms. Forty–one patients underwent subsequent operative intervention and were followed for a minimum of 6 months (avg= l9 months).

Results:

Fifty–five percent of patients had recreation of familiar pain during discography. Eight patients had recreation of familiar pain at multiple levels. Positive rates by level were as follows: L1–2, 0%(0/6); L2–3,10% (2/20); L3–4, 20% (11/47); L4–5, 20% (11/63) and L5–S, 41% (25/61). Thirty–three percent had a positive discogram at the level of their prior operation while nine patients reported recreation of pain at a level adjacent to a fusion. Sixty–eight percent of patients with positive discograms had greater than four out of ten pain at other levels. Half of all discograms had degenerative morphology with annular tears in an additional 20%. Forty–one patients has subsequent surgery consisting of 14 posterior fusions, 20 anterior fusions and six circumferential including 27 interbody fusions. Forty–six percent of surgical patients had a satisfactory outcome as defined by return to employment, lack of persistent narcotic use and pain characterized as minimal to mild. Patients with a good surgical outcome were as likely to have a positive discogram as patients with poor outcome (68% vs. 67%). Patients with good outcomes were significantly less likely to have workman's compensation claims, 26% vs. 61%, respectively (P less than 0.05).

Conclusion:

Although fusion in patients with failed back syndrome can be beneficial, discography in this setting demonstrates a high positive rate and is not a determinant factor in outcome. Abnormal morphology is commonplace and patients frequently report multiple levels of pain. In patients with failed back syndrome, discography should be interpreted with caution and may be best applied to limit fusion length.