ABSTRACT

Objective: To determine the frequency of degenerative disc pathology in patients with ankylosing spondylitis (AS) and explore its association with parameters of disease activity.

Methods: Patients between 15 and 65 years of age diagnosed with AS whose lumbar magnetic resonance imaging records were available in the registry database were enrolled. A total of 88 patients and 440 discs were evaluated. Modic classification was used for endplate degeneration, and the Pfirrmann scale, and the degree of disc herniation were analysed for disc degeneration. Aforementioned parameters were evaluated to determine whether they were associated with erythrocyte sedimentation rate, serum C-reactive protein (CRP) and the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). Values were expressed as frequencies and percentages for categorical variables. Spearman’s test was used for correlation analysis.

Results: Among 440 discs examined, Modic changes were detected in 13% (person count [PC]: 30.7%) and Modic type 2 changes were the most common (disc count [DC]: 8.9%, PC: 25%). The most frequent Pfirrmann change was grade 1 degeneration (DC: 57.7%, 254 discs), and the most common form of disc herniation was bulging disc (DC: 21.7%, PC: 67%). A positive correlation was found between L1-L2 disc herniation and BASDAI activity and between L2-L3 disc herniation and CRP level (p < 0.05).

Conclusion: A high prevalence of Modic type 2 changes and bulging herniation was found. While this study may provide some insight for degenerative disc disease in AS, further studies involving a larger number of patients and a control group are needed.