Costovertebral and costotransverse joint involvement in spondylarthritis by routine chest computed tomography

Background In spondyloarthritis (SpA) patients, costovertebral (CV) and costotransverse (CTr) joint are affected however these involvements are not routinely examined in clinical practice. Clinical characteristics of these involvements need further assessment. Objectives In this study, we aimed to determine the characteristics of CV and CTr joint involvements in SpA patients by routine chest computed tomography (CT). Methods SpA patients who have been requested a chest CT for any reason between January 2010 and December 2020 were retrieved from medical records and included in this retrospective cross-sectional analysis. Of these subjects, 281 had a diagnosis of SpA confirmed with patients records and sacroiliac imaging. After the patient population was created, the patients were sorted according to the registration number and divided into groups of ten. One patient was selected from each group. Thirty age- and sex-matched rheumatoid arthritis (RA) patients and 30 healthy controls were selected. Thorax CT were re-examined for CV and CTr joints by an experienced radiologist. All joints were classified as: Normal (0); suspicious [1], mild [2], moderate [3], and severe [4]. A total of 44 joints were evaluated for each patient, 24 CV and 20 CTr joints. Results Of the SpA patients, 206 (73.3%) were diagnosed with AS, 63 (22.4%) with psoriatic arthritis (PsA), and 12 (4.3%) with non-radiographic axial SpA (nr-AxSpA). 34 (54%) of PsA patients had axial PsA. Total scores of CV joint were different between diseases (AS 35 (0-96), PsA 16 (0-73), axial PsA 16 (0-73), peripheral PsA 20 (1-53), nr-AxSpA 6.5 (0-42), RA 15.5 (0-50), healthy control 13 (0-48) (p<0.001)) (Figure 1). Similarly, total scores of CTr joint were different between diseases (AS 16 (0-80), PsA 13 (0-34), axial PsA 12 (0-34), peripheral PsA 14 (0-32), nr-AxSpA 14 (2-31), RA 6.5 (0-24), healthy control 4 (0-20) (p<0.001)). In AS patients, 123 were male and 83 were female. Male AS patients had higher CV and CTr scores than female AS patients (Male CV score:52 (0-96) CTr score:20 (0-80); Female CV score:22 (0-96), CTr score:12 (0-79), p<0.001). In male AS patients, strong negative correlations between chest expansion and joint involvement of CV (r=-0.612, p<0.001) and CTr (r=-0.618, p<0.001) were found. In addition, strong positive correlations were observed between CV joints and lumbar modified stoke ankylosing spondylitis spinal score (mSASSS) (r=0.742 p<0.001), CV joints and cervical mSASSS score (r=0.754 p<0.001), CTr joints and lumbar mSASSS score (r=0.638 p<0.001), CTr and cervical mSASSS score (r=0.654 p<0.001). Conclusion In this study, we have found that CV and CTr joint involvement on thorax CT were more severe in AS patients and were associated with mSASSS and it negatively affects chest expansion. In a study with 25 AS patients, CV and CTr joint involvements were 80% and 60%, respectively and negative correlation with chest expansion were observed [1]. Another study showed moderate correlation mSASSS and arthritis of CV or CTr joints in AxSpA patients with MRI [2]. Our results are in line with the literature. In the light of these results, it may be beneficial to evaluate these joints, which have the potential to be overlooked clinically, and to initiate patients with CTr and CV joint involvement in exercise programs in the early period. References [1]Cerrahoglu L, Unlu Z, Can M, et al. (2002) Lumbar stiffness but not thoracic radiographic changes relate to alteration of lung function tests in ankylosing spondylitis. Clin Rheumatol. 21(4):275-279. [2]Kim JG, Jung JY, Lee J, et al. (2022) Can whole spine magnetic resonance imaging predict radiographic progression and inflammatory activity in axial spondyloarthritis? Joint Bone Spine. 89(4):105352. Figure 1. Distribution of costovertebral joint scores according to diseases AS: Ankylosing spondylitis, AxPsA: Axial psoriatic arthritis, nr-AxSpA: non-radiographic axial spondyloarthritis, PsA: psoriatic arthritis, RA: rheumatoid arthritis Acknowledgements: NIL. Disclosure of Interests None Declared.