Background Tumor necrosis factor alpha (TNFα) have been identified as possible causes of Non-specific low back pain (LBP). This raises question of the influence of TNFα-inhibition at the development of degenerative changes as seen on magnetic resonance imaging (MRI).
Objectives The aim of this report was to assess the degree of degenerative changes in ax-SpA patients before and after 3 and 5 years treatment with TNFα-inhibitors.
Methods Forty ax-SpA patients (mean age 40.7 yrs (SD 10.8), 80% males, 120 discs), with sacroiliitis on MRI, a BASDAI of >30 mm and clinical indication for TNFα inhibitor therapy. MRI of the lumbar spine were obtained before initiation of TNFα inhibitor therapy (baseline), and after 3 and 5 years follow-up. The MRI-scans were evaluated for degenerative changes. The findings were reported as “present” or “not present” and at follow-up as “unchanged”, “deteriorated” or “improved”. The results were compared with available data from healthy controls and non-specific LBP.
Results At baseline 16 patients (40%) had a normal MRI, 22 (55%) decreased signal, 14 (35%) height reduction, 9 (23%) disc herniation, 2 (5%) Modic Type 1, 1 (3%) Modic Type 2, 3 (7%) Schmorl's node, 3 (7%) HIZ. Among 120 discs in total, 26 (22%) had decreased signal, 17 (14%) height reduction, 12 (10%) disc herniation, 2 (2%) Modic Type 1, 1 (1%) Modic Type 2, 5 (4%) Schmorl's node, and 3 (3%) HIZ.
At 3 years follow-up, development of the following new degenerative changes was noted: 7 discs (6.0%) showed decreased signal and 3 (3%) height reduction, disc herniation, Modic type 1 and Schmorl's nodes. Corresponding numbers from 3 to 5 years' follow-up were: 3 disc (3.6%) decreased signal, 2 (1.7) Modic Type 1 and 1 (1.0%) Schmorls nodes. There were improvement in 4 (3%) with respect to disc herniation, Modic type 1 and HIZ.
Conclusions The frequency of degeneration at baseline was comparable to the general population and patients with non-specific LBP, 16 - 50% [1.2]. The discs undergo morphological and cellular changes with age. However, in this study the progression and development of decreased signal, disc herniation and Modic type 1 were less pronounced than expected (14 - 42% progression in 4 years have been reported in non-specific LBP patients).  Surprisingly, there was a small improvement of the degeneration of the discs.
Conclusion The study suggest that the included patients with ax-SpA treated with TNFα-inhibition seemed to develop less degeneration in the lower lumbar spine over 5 years than expected from previous data from healthy persons and patients with LBP.
Keller, A., et al., Are Modic changes prognostic for recovery in a cohort of patients with non-specific low back pain? Eur Spine J, 2012. 21(3): p. 418-24.
Cheung, K.M., et al., Prevalence and pattern of lumbar magnetic resonance imaging changes in a population study of one thousand forty-three individuals. Spine (Phila Pa 1976), 2009. 34(9): p. 934-40.
Kjaer, P., et al., Magnetic resonance imaging and low back pain in adults: a diagnostic imaging study of 40-year-old men and women. Spine (Phila Pa 1976), 2005. 30(10): p. 1173-80.
Disclosure of Interest : None declared