Correlation of the Severity of Lumbar Disc Degeneration, Using a Validated Classification, with Provocative Discography

Background: Over several decades, investigators have been trying to identify the painful degenerate disc. Their work included two main methods. The first was to set criteria on the radiological investigations, mainly the MRI scan, to describe the severity of the degenerative disc disease (DDD); and the second was to perform discographies. Neither of these two methods precluded the need for the other. Purpose: Using Pfirrmann's classification, we correlated the static MRI images, for the severity of disc degeneration, with the dynamic lumbar discography, aiming at improving the identification of painful 'discogenic' intervertebral segments. Study Design: Prospective cohort study. Patient Sample and Method: 69 patients (45 females, 24 males). The average age was 38.9 years (range 20-56). All patients had DDD on lumbar MRI scans. The severity of DDD was graded using Pfirrmann's classification. A total of 162 discographies were performed using "miss the facet joint, double needle technique". Outcome Measures: During discography typical or concordant pain only was regarded as positive. Among each of the five Pfirrmann grades, the percentage of positive discographies was calculated. Significance and correlation were then investigated using the Chi-squared and Spearman's correlation tests. Results: The percentages of positive provocative discography for concordant pain among the five Pfirrmann's grade were 0%, 9.1%, 71.4%, 100% and 100% respectively. Statistical analysis showed a high correlation between the severity of DDD on MRI scan and the result of the provocative discography. Conclusion: The higher the grade of segmental DDD, the more likely it will be painful on discography. All discs showing Pfirmann grade IV and V disease were painful on discography.