A comparative study to evaluate disc degeneration on magnetic resonance imaging in patients with chronic low back pain and asymptomatic individuals

Objectives: The present study aimed to investigate the association of disc degeneration with low back pain and the effect of ageing on disc degeneration in low back pain versus asymptomatic individuals. Methodology: A total of 50 patients with chronic low back pain (Group A) were compared to 25 healthy controls (Group B). Both the groups were subjected to magnetic resonance imaging of the lumbar spine and the disc degeneration was measured by the Pfirrmann grading system. The study group (Group A) was further sub-grouped into A(1) (lumbar spondylosis, n= 11), A(2) (mechanical back pain, n=-13) and A(3) (lumbar disc herniation, n= 26). Results: There was a statistically significant difference in degeneration at the L4-L5 ( p= 0.001) and L5-S1 disc levels (p= 0.001) between the two groups and contiguous disc involvement was more in low back pain patients. The subgroups of group A showed no statistically significant difference. Age showed a strong positive correlation (r > 0.5) at all the lumbar levels (except at the L5-S1, r= 0.487) with Pfirrmann grading in Group A ( p= 0.001). There was a weak positive correlation (r = 0.414) between age and Pfirrmann grade in the controls (p= 0.04) at the L4-L5 level only. Conclusions: Significantly higher Pfirrmann grading on magnetic resonance imaging was found at the L4-5 and L5-S1 levels in symptomatic patients suggesting higher involvement of these levels. Progressive disc degeneration is seen with ageing but in patients with low back pain, it is significantly accelerated.