Abstract
Introduction
Experimental studies have demonstrated accelerated disc degeneration after various intradiscal procedures. However, there are only a few long-term follow-up studies using MRI images to confirm the progressive disc degeneration after discography. The aim of this study is to evaluate disc degeneration after discography over 5-year follow-up and to determine possible risk factors for enhancing disc degenerations after discography
Material and Methods
239 subjects with chronic low back pain underwent multi-level discography to confirm discogenic pain in our institute from January 2006 to June 2009. Thirty-eight subjects who did not operate due to negative study with normal (Grade 1 and 2) to moderate (Grade 3) disc degeneration prior to discography and followed for more than 5 years were enrolled in our study. The routine multi-level discography technique and determination of positive study using original work by Walsh et al was performed in all study subjects. Pre- and post-discography MRI and CT scan were analyzed by two blind independent observers to evaluate degree of disc and endplate degenerations. The progression of disc degeneration was analyzed for correlation with 1) subjects demographic data, 2) pre-discography disc degeneration, 3) levels of discography and 4) discography findings.
Results
Mean age of the subjects at time of discography was 38.1 ± 6.4 years and mean time to final MRI follow-up was 68.0 ± 3.1 months. 2-level discography was done in 19 subjects and 3-level in 18; total 92 disc (L2/3: 5, L3/4: 30, L4/5: 36, L5/S1: 21) There was progression of disc degeneration in 23 disc (23.9%); 5 (6.4%) from normal and 18 (19.5%) from moderate disc degeneration group. There were 16 (17.3%) new disc herniation and 9 (9.7%) new HIZ, however, there was no significant difference between the locations of herniation. Moreover, the differences of mean disc height and endplate degeneration were not statistically significant. The progression of disc degeneration was significantly higher in young age group (<35 years), lower level disc group (L4/5 and L5/S1) and moderate (Grade 3 to 4) disc degeneration group. Multi-level injection, failed discography (annulography) and higher grade of discography findings revealed no positive correlation with progression of disc degeneration.
Conclusion
Diagnostic discography resulted in accelerated disc degeneration in 5-year follow-up study. However, MR findings suggested that annulus puncture with small gauze needle may not be the cause of new disc herniation. Younger age, lower level disc and advanced degeneration prior to discography were the risk factors for progression of disc degeneration. Careful consideration of risk and benefit should be used in recommending procedures involving disc injection.